All methods described here have been approved by the Internal Review Board for human subject research at the University of Kansas, Lawrence, KS.
1. Selecting Participants
<ol>
	<li>Use right-handed participants for DVF research. In rare cases (10%), left-handed individuals are lateralized for language processing in the right hemisphere, which would result in scalp-recorded ERP components with non-typical topographical distributions.</li>
	<li>Have participants complete the Edinburgh Handedness Inventory9 to determine strong right-handedness. Scores of eight or higher indicate strong right-handedness.</li>
</ol>
2. Stimuli
<ol>
	<li>Request a research copy of the International Affective Picture System (IAPS)10 via the Center for the Study of Emotion and Attention&#39;s website11. Select stimuli from the IAPS according to the specifications in steps 2.2-2.4. The IAPS comes with an image file for each stimulus and a tab-delimited text file containing the normed ratings of valence and arousal for each image.
	<ol>
		<li>Use a spreadsheet program to view the norms and make the stimuli selections. For a complete list of the stimuli selected for O&#39;Hare, Atchley, and Young (2016) see Table 1. 
		NOTE: This stimulus set provides norms for the rated valence and arousal of emotional stimuli. The norms for the stimuli were created via participant ratings on the Self-Assessment Mannequin10. This scale depicts a graphic figure that ranges from a frowning, unhappy figure to a smiling, happy figure for valence, and a relaxed, sleepy figure to an excited, wide-eyed figure for arousal. Valence is rated on a 9-point Likert scale with 1 equaling the most unpleasant (frowning, unhappy figure) and 9 equaling the most pleasant (smiling, happy figure). Arousal is also rated on a 9-point Likert scale with 1 equaling the least arousing (relaxed, sleepy figure) and 9 equaling the most arousing (excited, wide-eyed figure). The components of each image that evoke emotional responses are located centrally in each image.</li>
	</ol>
	</li>
	<li>Create three valence groups of images with 60 images in each group: unpleasant, pleasant and neutral, using the norms provided in the IAPS manual12.
	<ol>
		<li>To do this, sort the IAPS images by their average valence rating. Unpleasant stimuli range in average valence rating from 1 to 3.99. Neutral stimuli range in average valence rating from 4 to 6.99. Pleasant stimuli range in average valence rating from 7 to 9. Each valence group must significantly differ from each other in average valence rating with no overlap in their ranges.</li>
		<li>Confirm that valence groups significantly differ from each other using independent samples t-tests13. Picture complexity across the image groups is not controlled as image complexity has not been found to influence the LPP14.</li>
	</ol>
	</li>
	<li>Within both the unpleasant and pleasant valence stimuli, create high and medium arousal subgroups of 30 images each.</li>
	<li>Within the neutral valence stimuli, create medium and low arousal subgroups. High arousal subgroups range in average arousal ratings from 4.30 to 8.70 and do not significantly differ from each other on average arousal rating. Medium arousal subgroups range in average arousal ratings from 2.40 to 7.29 and do not significantly differ from each other on average arousal rating. The low arousal subgroup ranges in average arousal ratings from 1.4-5.44.</li>
	<li>Once the stimuli have been selected, test them (via t-tests)13 to ensure the stimuli groups are reliably different. 
	NOTE: Each of the arousal subgroups (high, medium, and low) must significantly differ from each other in average arousal rating, but arousal subgroups within a valence group do not significantly differ from each other in valence. This allows for examination of 1) valence effects alone, 2) arousal effects alone, and 3) interactive effects between valence and arousal.</li>
	<li>Using an image-editing software program, resize the final stimulus images to ensure that they will be presented at 17.06 horizontal and 10.85 vertical degrees of visual angle on the stimulus-presentation monitor.
	<ol>
		<li>Calculate the visual angle (V) using the formula, V = 2arctan(S/2D)15, where S = the height or width of a visual object, and D = the distance from the viewer&#39;s pupil to the visual object. The size of the stimulus images will depend upon the distance between the participant&#39;s pupils and the stimulus-presentation monitor (D).</li>
	</ol>
	</li>
	<li>Create mask stimuli for backward masking of the image stimuli. Mask stimuli consist of an array of backward slashes (i.e., &#34;\&#34;) that match the spatial dimensions of the images. Create a textbox that has the same dimensions in pixels as the image stimuli in an image-editing software program. Enter backward slashes into the textbox until they fill the entire space without changing the dimensions specified. Save this textbox as an image to create the mask stimulus.</li>
	<li>For the DVF paradigm, create the image-presentation slides to be loaded into the stimulus presentation software.
	<ol>
		<li>In an image-editing software program, center a fixation mark (&#34;+&#34;) in the middle of the image. Place your first stimulus image centered vertically with its right edge 3&#176; of visual angle to the left of the fixation mark.</li>
		<li>Create a brown rectangle with the same dimensions as the stimulus image and place it also centered vertically with its left edge 3-degrees of visual angle to the right of the fixation mark. Save this arrangement as the left visual field presentation of this stimulus image.</li>
		<li>Switch the location of the stimulus image and the brown rectangle and save this arrangement as the right visual field presentation of this stimulus image. Do this for all stimulus images (Figure 1).</li>
	</ol>
	</li>
	<li>For the DVF paradigm, create the mask-presentation slides to be loaded into the stimulus presentation software in the same manner as was done for the image-presentation slides. Place the mask image on both sides of the fixation mark with both inner edges 3-degrees of visual angle from the fixation mark (Figure 2). Save this arrangement as the mask stimulus for the DVF paradigm.</li>
</ol>
3. Experimental Equipment
<ol>
	<li>Use Silver-Silver chloride (Ag-AgCl) active-electrodes or other EEG electrodes to record EEG from scalp positions according to the international 10-20 system16. Position one additional electrode above and another below the right eye to record vertical eye movements.</li>
	<li>Use EEG acquisition software for data acquisition with a sampling rate of 250-500 Hz, depending upon equipment specifications. For a detailed consideration of EEG acquisition parameters see Luck (2014)17.</li>
	<li>Present stimuli via an stimulus-presentation software package18 on a computer with a mirrored 24-inch stimulus-presentation liquid crystal display monitor (1,920 x 1,200 resolution) that is in a separate, electrically-shielded, and sound attenuated room. Place only the mirrored monitor within the shielded room, while keeping the computer out of the experimental room reduces electrical noise. Sound attenuation reduces the occurrence of auditory-evoked potentials in the EEG data. The stimulus-presentation software package must allow for users to set the presentation durations and screen locations of stimuli.</li>
</ol>
4. Preparing the Participant
<ol>
	<li>Have participants complete informed, written consent prior to providing any data.</li>
	<li>Have participants complete a demographic survey to provide sex, age, handedness, native language, vision, and neurological history. Collect sex and age for reporting in final study dissemination. Use all other demographic information to determine if the participant meets the criteria for inclusion in the study: right-handed (assessed via the Edinburgh Handedness Inventory), native English speaker collected via self-report (or native to the language used in the study instructions), normal or correct-to-normal vision, and no history of neurological trauma.</li>
	<li>Apply EEG electrodes onto the participant. Any EEG montage that covers occipital-parietal regions of the scalp is appropriate for recording the LPP response.</li>
	<li>Seat participants in a dark, electrically-shielded, sound-attenuated room. Use a chin rest to stabilize the head and minimize movement. Position the chin rest the correct distance away from the stimulus-presentation monitor to maintain the D variable used in the visual angle calculations. Place a keyboard (or response box) in front of the participant for response collection via their right hand.</li>
	<li>Check the data signal to ensure that all channel impedances are less than 50 kiloohms17.</li>
	<li>Instruct participants to passively view the image stimuli without shifting their eyes away from the center of the screen. Display a fixation mark (&#34;+&#34;) at the center of the screen to help participants fixate17. Instruct the participant that there will be a recognition quiz following each block of images, so it is important that they pay attention. Each participant only completes the CVF or the DVF paradigm, creating a between-subjects design. 
	NOTE: Both CVF and DVF paradigms can be conducted on the same participant to create a within-subjects design. If this is done, counterbalance the order of the two paradigms to control for any familiarity effects with the stimuli.</li>
</ol>
5. Central Visual Field (CVF) Paradigm
NOTE: In the CVF paradigm, randomly present image stimuli at the center of the screen. Each trial consists of a 500 ms central fixation (&#34;+&#34;) followed by a 150 ms presentation of the stimulus, followed by a backward mask that varies randomly in presentation duration between 2,000-4,000 ms. Jittered presentation duration for the mask serves to reduce any anticipatory ERP responses to the onset of the next trial20.
<ol>
	<li>To specify the presentation durations and stimuli locations create separate presentation slides for the fixation, the stimulus images, and the mask stimulus in your stimulus-presentation software.
	<ol>
		<li>For the presentation of the fixation mark, specify the presentation of the plus sign symbol (&#34;+&#34;) centered both vertically and horizontally and set the duration to 500 ms. This can be done through the properties for this slide.</li>
		<li>For the presentation of the stimulus, enter the image file names for the stimuli into a matrix or list object.</li>
		<li>On the image-presentation slide, place an image object centered both vertically and horizontally, and link this object to the list of image file names to load the image stimuli. Set the matrix or list object with the image file names to randomly select from the list without replacement of already selected stimuli. Set the duration of the image-presentation slide to 150 ms.</li>
		<li>For the mask-presentation slide, again place an image object centered both vertically and horizontally. This object can be directly linked to the mask image file by entering the file name in its properties. Set the duration of the mask-presentation slide to randomly vary between 2,000-4,000 ms.</li>
	</ol>
	</li>
	<li>Present image stimuli in four experimental blocks of 45 trials each (180 trials total). Each block has an equal number of stimuli from the valence/arousal conditions. This can be accomplished by creating four separate matrices or list objects with the image file names, each containing 7-8 images from each valence-arousal group (e.g., in list 1 there can be 7 high-arousing unpleasant images and in list 2 there can be 8 high-arousing unpleasant images). Participants passively view the image stimuli on each trial.</li>
	<li>Following each block, give a 10-item recognition test to ensure participants pay attention during the passive viewing portion of the study. Display six items on the recognition test from the preceding block and four items that are new. Select these six items so that they represented all categories of valence and arousal. Have participants respond via key press using their right hand indicating which stimuli they previously viewed.</li>
</ol>
6. Divided Visual Field (DVF) Paradigm
NOTE: The DVF paradigm is identical to the CVF paradigm, including the size of the image stimuli, except present each image stimulus laterally, to the left or right of the fixation mark using the image-presentation slides created in step 2.7 (see Figure 3)4.
<ol>
	<li>Present each image once in the left visual field and once in the right visual field. Present all stimuli in a fully randomized order.</li>
	<li>As each stimulus is presented twice, double the number (8) of experimental blocks and recognition tests for a total of 360 trials.</li>
	<li>Pair each image stimulus with the simultaneous presentation of a solid brown rectangle identical in stimulus dimensions on the opposite side of the fixation. This is done to reduce reflexive saccades to the stimulus. Additionally, the presentation duration of 150 ms is shorter than most saccade latencies21, meaning that if the participant shifts his/her eyes to the stimulus, it will be masked before the participant can fixate on it22.</li>
	<li>Present each stimulus and its paired brown rectangle with their inside edge 3&#176; of visual angle from the fixation. This is done to assure that the stimuli fall entirely within the regions of the retinas that are processed by only one hemisphere4.</li>
	<li>Backward mask both the stimulus and the brown rectangle using the same criteria and procedure as was done in the CVF paradigm20.</li>
</ol>
7. Data Analysis
<ol>
	<li>Remove any participant scoring less than 50 percent (chance) on the recognition test from the data, as it cannot be assured that he/she was paying attention to the stimuli.</li>
	<li>Preprocess and analyze EEG data using an EEG software package23. Filter data offline with a continuous 0.01-30 Hz bandpass, mark data fluctuating 200 &#956;v within a 100 ms time window as bad, correct eye blink artifacts using an average template generated from each individual participant, manually remove horizontal eye shifts from the data following visual inspection, and rereference data using the common average rereference24,25.</li>
	<li>Compute epochs of 1,000 ms after the onset of the stimuli according to a 200 ms pre-stimulus baseline26.</li>
	<li>Use visual inspection of the waveforms and the ERP literature to determine the topography of the LPP27. In this study, the LPP centered on channel CPz. In this case, average channels CPz, Pz, Cz, CP1 and CP2 together to create a representation of the LPP.</li>
	<li>In the DVF data, conduct a laterality analysis comparing the LPP amplitude across left occipital-parietal channels and right occipital-parietal channels to ensure that the DVF presentations did not shift the typical topography of the LPP component. Conduct paired-samples t-tests between channel pairs CP1 and CP2, CP3 and CP4, C1 and C2, C3 and C4, P1 and P2, and P3 and P4 respectively to ensure that they do not significantly differ from each other on average amplitude.</li>
	<li>As the LPP is a long, sustained component, extract two different LPP epochs: early (400-700 ms post-stimulus onset) and late (700-1,000 ms post-stimulus onset).</li>
	<li>Analyze the CVF LPP data via a 3 (Valence: unpleasant, pleasant, and neutral) by 2 (Epoch: early and late) within-groups analysis of variance (ANOVA) to ensure that the typical LPP effect of emotional stimuli generating larger LPP responses than neutral stimuli is present. This analysis is done to affirm that the stimuli were processed normally.</li>
	<li>To examine the interactive effects of valence and arousal on the LPP conduct a 2 (Valence: unpleasant and pleasant) by 2 (Arousal: high and low) by 2 (Epoch: early and late) within-groups ANOVA on the CVF LPP data.</li>
	<li>To examine the effects of hemisphere of presentation, conduct the ANOVA specified in section 7.8 with the additional factor of Hemisphere: left and right on the DVF LPP data.</li>
</ol>

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The authors have nothing to disclose.

In this study, manipulations of stimulus valence and arousal were used with the DVF paradigm to test theories of lateralized processing of emotion as they apply to the motivated attention network. However, DVF methodologies can be used to explore any lateralized processing of visual information. What is critical when using DVF paradigms is the control of the stimuli presentation to ensure that the information is isolated to one hemisphere for initial processing. There are several key steps to the DVF paradigm that contribute to this aspect of the research.
First, participants are instructed to keep their eyes fixated at the center of the screen. A fixation mark, bilateral dummy stimulus (or placeholder), and a head-stabilizing chin rest are used to assist participants with maintaining this fixation. Nonetheless, participants will occasionally shift their gaze to the laterally presented stimuli. Trials in which an eye shift occurred should not be included in the analyses, as fixating on the stimulus allows both hemispheres to receive the information simultaneously. In ERP research, horizontal eye shifts can be detected in the EEG data, and those trials can be removed. In behavioral research, it may be necessary to continuously use a mirror or eye tracking to monitor eye movements.
In addition to controlling for eye shifts, stimuli need to be presented in a manner that prevents bilateral processing. To do this, it is recommended that stimuli appear no less than 3&#176; of visual angle from the fixation. It is also important not to present stimuli too laterally, where visual acuity will decline. Stimuli extending beyond 10&#176; of visual angle from the fixation are at risk for low visual acuity (see reference4 for a detailed discussion). Additionally, stimuli need to be presented below the average express saccade latency (150 ms)21. Express saccades are reflexive eye shifts to changes in the visual field, such as a stimulus appearing. Additionally, displaying a backward mask following the offset of the stimulus disrupts any early, bilateral processing of the stimulus22. Presenting the mask stimulus immediately after the experimental stimulus does add another visual stimulus to the ERP window, possibly contaminating the resulting ERP components. However, consistently using the mask stimulus across all trials of interest still allows for the examination of the effects of stimulus variables, such as valence and arousal, beyond these basic visual processing effects, as they should cancel out across the comparison of conditions.
EEG and ERPs are one way to assess the impact of lateralized processing of stimuli. It is important when using these methodologies to know if the ERP components you intend to analyze are subject to shifting their topographies following lateralized presentations of stimuli. For the LPP, previous DVF studies did not find topographical shifts29,30, but other ERP components may be sensitive to visual field side of presentation. Larger ERP amplitudes are indices of additional processing resources being used to process any given presentation of a stimulus. For example, in this study, larger LPP responses were found in the late epoch for high-arousing unpleasant images presented to the left hemisphere. This is interpreted as the left hemisphere engaging in more elaborate processing of these stimuli compared to the right hemisphere or compared to pleasant or neutral stimuli.
Behavioral tasks can also be used to assess the effects of lateralized processing of stimuli. In this case, changes in accuracy or reaction time in response to the lateralized presentations of stimuli can be interpreted as differences in the efficiency of the two hemispheres in processing that type of information. For example, both accuracy and reaction time differences between hemispheres of presentation have been found in DVF semantic priming tasks31.
DVF paradigms can be limited in that the presentation duration of the stimuli must be kept below 150 ms to prevent saccades and bilateral processing. As such, complex stimuli that require longer processing may be inappropriate for this methodology. Further, DVF paradigms can only be used to make inferences about processing in an entire cerebral hemisphere. Investigating processing within specific brain regions at a finer level than cerebral hemisphere is not possible with DVF techniques alone. If specific brain regions are part of the research question, neuroimaging or ERP techniques must be used in concert with the DVF paradigm.
DVF paradigms provide an avenue for studying lateralized processing in the brain without the need for neuroimaging equipment. This makes the study of the brain more accessible to all researchers. In the study of lateralized processing of emotional information, future studies that pair DVF presentations of systematically controlled emotional stimuli with a behavioral task can further explore the unique contributions of each cerebral hemisphere to our emotional experience.

Several theories on lateralized processing have been posited for the two cerebral hemispheres. Among these include theories of emotional processing. The valence model1 proposes that the left hemisphere is specialized for pleasant emotions, while the right hemisphere is specialized for unpleasant emotions. The right hemisphere dominance hypothesis2 proposes that the right hemisphere is specialized for processing all emotional information compared to the left hemisphere. Finally, the Circumplex Theory3 proposes that in addition to frontal asymmetries for valence, the posterior regions of the right hemisphere are specialized for processing all high-arousing emotions. In order to test these lateralized theories of processing, methodologies that can differentiate processing between the two hemispheres must be used. While neuroimaging techniques can provide this information, they are often not readily accessible to most research scientists. Further, many standard cognitive paradigms, even when coupled with neuroimaging methodologies, do not isolate information processed within each hemisphere. Divided visual field (DVF) methodologies provide an avenue for behavioral and psychophysiological scientists to test lateralized theories of processing without the use of neuroimaging techniques.
DVF methodologies are based on the knowledge that a stimulus presented to one visual field is initially received and processed by the contralateral hemisphere4. DVF methodologies utilize lateralized presentations of stimuli at short intervals to allow one cerebral hemisphere to receive the information before the other5. As such, stimuli presented briefly to the right visual field are processed contralaterally by the left hemisphere, and stimuli presented to the left visual field are processed by the right hemisphere. In this manner, differences in initial processing of the information in a single hemisphere can be examined. For example, it is well established that the left hemisphere is specialized for processing linguistic information (for a meta-analysis see reference6). Research using DVF paradigms demonstrate increased processing speed when words are presented to the left hemisphere (i.e., displayed in the right visual field) compared to when presented to the right hemisphere.
In order to assess the processing differences between the two hemispheres, measures with finer temporal resolution than behavioral reaction times may be needed. Event-related potentials (ERPs) derived from human electroencephalography (EEG) data have a temporal resolution on the order of milliseconds (ms). As such, using ERP techniques in concert with DVF methodologies allows for a refined assessment of processing differences between the two hemispheres. Initially, central visual field (CVF) presentations of the stimuli can be used to replicate established ERP effects. Then, DVF presentations of the stimuli can be used to examine the unique contributions of each hemisphere to the propagation of these ERP effects. Of particular interest for the current study7, the late positive potential (LPP) has been identified as an ERP component sensitive to the emotional arousal of a stimulus8. Interestingly, the LPP has not been found to consistently differentiate between unpleasant and pleasant stimuli, but rather, responds equally to emotional stimuli relative to neutral stimuli. This study was designed to test the lateralized processing of emotion theories using the LPP as an index of motivated attention toward emotional stimuli between the two hemispheres.
Further, this study systematically examines both the valence and arousal dimensions of the emotion stimuli across early and late manifestations of the LPP. These stimulus manipulations in combination with both CVF and DVF stimulus presentations are unique to the literature, as they allow for examining the unique and interactive influences of valence, arousal, and hemisphere of processing on the propagation of the LPP. As such, the influence of immediacy for action signaled by unpleasant compared to pleasant stimuli, which should differentially engage motivated attention and thus the LPP, can be explored.

<table><tbody><tr><td>64-channel Ag-AgCl active electrodes</td><td>Cortech Solutions</td><td>DA-AT-ESP32102064A/DA-AT-ESP32102064B</td><td>EEG electrodes for data collection</td></tr><tr><td>ActiveTwo Base System</td><td>Cortech Solutions</td><td>DA-AT-BCBS</td><td>Digitizes and ampliphies EEG data at 500 Hz</td></tr><tr><td>E-Prime Professional 2.0</td><td>Psychology Software Tools</td><td>NA</td><td>Stimulus presentation software, available at https://www.pstnet.com/eprime.cfm</td></tr><tr><td>CURRY 7.0</td><td>Compumedics Neuroscan</td><td>NA</td><td>EEG/ERP data processing and analysis, available at http://compumedicsneuroscan.com/products/by-name/curry/</td></tr></tbody></table>

central and divided visual field presentation of emotional images to measure hemispheric differences in motivated attention

Two dominant theories on lateralized processing of emotional information exist in the literature. One theory posits that unpleasant emotions are processed by right frontal regions, while pleasant emotions are processed by left frontal regions. The other theory posits that the right hemisphere is more specialized for the processing of emotional information overall, particularly in posterior regions.
Assessing the different roles of the cerebral hemispheres in processing emotional information can be difficult without the use of neuroimaging methodologies, which are not accessible or affordable to all scientists. Divided visual field presentation of stimuli can allow for the investigation of lateralized processing of information without the use of neuroimaging technology. 
This study compared central versus divided visual field presentations of emotional images to assess differences in motivated attention between the two hemispheres. The late positive potential (LPP) was recorded using electroencephalography (EEG) and event-related potentials (ERPs) methodologies to assess motivated attention. Future work will pair this paradigm with a more active behavioral task to explore the behavioral impacts on the attentional differences found.

To replicate previous research on the LPP, both LPP responses to unpleasant and pleasant images should be larger than LPP responses to neutral images. This is confirmed by the CVF analysis, which finds the LPP in the early epoch to be significantly larger to unpleasant (M = 1.90 &#956;v) and pleasant (M = 1.71 &#956;v) images compared to neutral images (M = 0.72 &#956;v), but unpleasant and pleasant images are not found to be significantly different from each other. Interestingly, in the late epoch, the LPP is found to be larger for unpleasant (M = 1.19 &#956;v) compared to pleasant images (M = 0.56 &#956;v).
To examine the effects of hemisphere of processing on the LPP response to emotional images, differences in the LPP between the hemispheres of presentation are of interest. In this study, the LPP is found to be larger in the early epoch compared to the late epoch for all image presentations except for high-arousing unpleasant images presented to the left hemisphere. These images are not found to elicit significantly different LPP responses between the two epochs (see Table 2). In other words, the LPP response to high-arousing unpleasant images is sustained in comparison to medium-arousal unpleasant images and all pleasant images. This finding can be used to inform the theories of lateralized emotion processing. In particular, these data support theories of emotion processing that propose the right hemisphere is specialized for general emotion identification, while the left hemisphere is specialized for creating specific action plans in response to emotional stimuli28. Here, it appears that the left hemisphere engages high-arousing unpleasant images for longer, possibly to address the need for action or not.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56257/56257fig1.jpg" /> 
Figure 1: A schematic of the Divided Visual Field (DVF) paradigm. Each trial consists of a centrally presented fixation (&#34;+&#34;) for 500 ms, followed by a lateralized stimulus presentation that is paired with a brown rectangle for 150 ms, followed by a backward mask for a random interval between 2,000-4,000 ms. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56257/56257fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56257/56257fig2.jpg" /> 
Figure 2: Mask Presentation for DVF Paradigm. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56257/56257fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/56257/56257fig3.jpg" /> 
Figure 3: The DVF paradigm is identical to the CVF paradigm, including the size of the image stimuli, except present each image stimulus laterally, to the left or right of the fixation mark using the image-presentation slides. <a href="https://cloudflare-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/56257/56257fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>High-Arousing Unpleasant</td>
			<td>Medium-Arousing Unpleasant</td>
			<td>High-Arousing Pleasant</td>
			<td>Medium-Arousing Pleasant</td>
			<td>Medium-Arousing Neutral</td>
			<td>Low-Arousing Neutral</td>
		</tr>
		<tr>
			<td>3500</td>
			<td>9000</td>
			<td>8300</td>
			<td>1600</td>
			<td>1080</td>
			<td>2271</td>
		</tr>
		<tr>
			<td>6360</td>
			<td>2750</td>
			<td>4607</td>
			<td>2341</td>
			<td>1030</td>
			<td>2280</td>
		</tr>
		<tr>
			<td>9300</td>
			<td>9432</td>
			<td>5629</td>
			<td>7230</td>
			<td>2810</td>
			<td>7234</td>
		</tr>
		<tr>
			<td>3150</td>
			<td>6311</td>
			<td>8034</td>
			<td>1590</td>
			<td>8010</td>
			<td>7700</td>
		</tr>
		<tr>
			<td>6315</td>
			<td>9265</td>
			<td>4608</td>
			<td>2345</td>
			<td>9913</td>
			<td>2210</td>
		</tr>
		<tr>
			<td>3400</td>
			<td>9320</td>
			<td>8400</td>
			<td>1999</td>
			<td>6930</td>
			<td>2221</td>
		</tr>
		<tr>
			<td>6230</td>
			<td>2276</td>
			<td>8180</td>
			<td>1463</td>
			<td>7560</td>
			<td>5120</td>
		</tr>
		<tr>
			<td>6300</td>
			<td>3181</td>
			<td>8490</td>
			<td>4622</td>
			<td>1303</td>
			<td>7590</td>
		</tr>
		<tr>
			<td>2683</td>
			<td>3051</td>
			<td>4290</td>
			<td>1500</td>
			<td>1112</td>
			<td>4233</td>
		</tr>
		<tr>
			<td>9620</td>
			<td>9911</td>
			<td>8170</td>
			<td>2331</td>
			<td>6900</td>
			<td>2516</td>
		</tr>
		<tr>
			<td>6370</td>
			<td>9420</td>
			<td>8080</td>
			<td>7352</td>
			<td>2780</td>
			<td>4000</td>
		</tr>
		<tr>
			<td>6200</td>
			<td>3061</td>
			<td>8470</td>
			<td>2224</td>
			<td>2690</td>
			<td>5534</td>
		</tr>
		<tr>
			<td>6313</td>
			<td>6243</td>
			<td>8370</td>
			<td>8497</td>
			<td>5535</td>
			<td>2490</td>
		</tr>
		<tr>
			<td>9800</td>
			<td>9006</td>
			<td>8501</td>
			<td>8210</td>
			<td>7211</td>
			<td>7180</td>
		</tr>
		<tr>
			<td>9921</td>
			<td>9340</td>
			<td>4220</td>
			<td>2650</td>
			<td>1935</td>
			<td>2830</td>
		</tr>
		<tr>
			<td>9910</td>
			<td>9561</td>
			<td>8190</td>
			<td>2310</td>
			<td>6314</td>
			<td>9070</td>
		</tr>
		<tr>
			<td>9810</td>
			<td>3300</td>
			<td>4676</td>
			<td>4610</td>
			<td>7820</td>
			<td>7224</td>
		</tr>
		<tr>
			<td>6560</td>
			<td>3101</td>
			<td>4690</td>
			<td>1721</td>
			<td>1101</td>
			<td>2383</td>
		</tr>
		<tr>
			<td>6212</td>
			<td>3180</td>
			<td>4687</td>
			<td>8090</td>
			<td>7503</td>
			<td>2272</td>
		</tr>
		<tr>
			<td>6570</td>
			<td>2205</td>
			<td>4659</td>
			<td>2352</td>
			<td>5970</td>
			<td>7920</td>
		</tr>
		<tr>
			<td>6540</td>
			<td>9280</td>
			<td>4689</td>
			<td>5460</td>
			<td>9582</td>
			<td>7031</td>
		</tr>
		<tr>
			<td>6415</td>
			<td>9415</td>
			<td>4670</td>
			<td>2303</td>
			<td>1240</td>
			<td>9210</td>
		</tr>
		<tr>
			<td>6821</td>
			<td>9342</td>
			<td>8186</td>
			<td>2208</td>
			<td>9402</td>
			<td>9401</td>
		</tr>
		<tr>
			<td>9050</td>
			<td>9220</td>
			<td>4680</td>
			<td>8540</td>
			<td>3210</td>
			<td>2480</td>
		</tr>
		<tr>
			<td>6260</td>
			<td>9560</td>
			<td>8030</td>
			<td>2395</td>
			<td>1390</td>
			<td>7595</td>
		</tr>
		<tr>
			<td>2730</td>
			<td>9140</td>
			<td>5470</td>
			<td>4641</td>
			<td>2230</td>
			<td>2590</td>
		</tr>
		<tr>
			<td>6510</td>
			<td>9421</td>
			<td>4660</td>
			<td>4700</td>
			<td>1945</td>
			<td>7025</td>
		</tr>
		<tr>
			<td>6312</td>
			<td>9301</td>
			<td>8200</td>
			<td>5480</td>
			<td>1230</td>
			<td>2215</td>
		</tr>
		<tr>
			<td>9600</td>
			<td>9181</td>
			<td>5621</td>
			<td>7260</td>
			<td>2410</td>
			<td>7186</td>
		</tr>
		<tr>
			<td>9250</td>
			<td>9435</td>
			<td>8185</td>
			<td>8461</td>
			<td>9411</td>
			<td>2441</td>
		</tr>
	</tbody>
</table>
Table 1: Stimuli ID numbers for selected stimuli for O&#39;Hare, Atchley and Young (2016) from the IAPS sorted by arousal and valence groups.
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td></td>
			<td colspan="2">Left Hemisphere</td>
			<td>Right Hemisphere</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td>Early Epoch</td>
			<td>Late Epoch</td>
			<td>Early Epoch</td>
			<td>Late Epoch</td>
		</tr>
		<tr>
			<td>High-Arousing Unpleasant</td>
			<td>2.839</td>
			<td>2.629</td>
			<td>2.48</td>
			<td>0.968*</td>
		</tr>
		<tr>
			<td>High-Arousing Pleasant</td>
			<td>2.521</td>
			<td>1.783*</td>
			<td>3.03</td>
			<td>1.8*</td>
		</tr>
	</tbody>
</table>
Table 2: Mean LPP amplitudes for the DVF analysis.

Watch this Scientific Journal Video about Central and Divided Visual Field Presentation of Emotional Images to Measure Hemispheric Differences in Motivated Attention at JoVE.com

Central and Divided Visual Field Presentation of Emotional Images to Measure Hemispheric Differences in Motivated Attention

This study compared central versus divided visual field presentations of emotional images to assess differences in motivated attention between the two hemispheres. The late positive potential (LPP) was recorded using electroencephalography (EEG) and event-related potentials (ERPs) methodologies to assess motivated attention.

Two dominant theories on lateralized processing of emotional information exist in the literature. One theory posits that unpleasant emotions are processed ...

central-divided-visual-field-presentation-emotional-images-to-measure

Nanyang Technological University

Research

JoVE Journal

Behavior

7.5K Views.  University of Massachusetts Dartmouth. Deze studie vergeleken centraal versus verdeelde gezichtsveld presentaties van emotionele beelden te beoordelen van de verschillen in gemotiveerde aandacht tussen de twee hemisferen. Het laat positieve potentieel (LPP) werd opgenomen met behulp van elektro-encefalografie (EEG) en gebeurtenis-gerelateerde mogelijkheden (ERPs) methoden te beoordelen gemotiveerd aandacht.

Video: Central and Divided Visual Field Presentation of Emotional Images to Measure Hemispheric Differences in Motivated Attention

Measurement of Fronto-limbic Activity Using an Emotional Oddball Task in Children with Familial High Risk for Schizophrenia

Adolescence is a critical developmental period where the early symptoms of schizophrenia frequently emerge. First-degree relatives of people with schizophrenia who are at familial high risk (FHR) may show similar cognitive and emotional changes. However, the neurological changes underlying the emergence of these symptoms remain unclear. This study sought to identify differences in frontal, striatal, and limbic regions in children and adolescents with FHR using functional magnetic resonance imaging. Groups of 21 children and adolescents at FHR and 21 healthy controls completed an emotional oddball task that relied on selective attention and the suppression of task-irrelevant emotional information. The standard oddball task was modified to include aversive and neutral distractors in order to examine potential group differences in both emotional and executive processing. This task was designed specifically to allow for children and adolescents to complete by keeping the difficulty and emotional image content age-appropriate. Furthermore, we demonstrate a technique for suitable fMRI registration for children and adolescent participants. This paradigm may also be applied in future studies to measure changes in neural activity in other populations with hypothesized developmental changes in executive and emotional processing.

This paper describes how to use the emotional oddball task and fMRI to measure brain activation in children and adolescents at familial high risk for schizophrenia (FHR).&#160;FMRI was used to measure differences in fronto-striato-limbic regions during an emotional oddball task. Children with FHR exhibited abnormal functional activation during adolescence.

Adolescence is a critical developmental period where the early symptoms of schizophrenia frequently emerge. First-degree relatives of people with ...

Brain Imaging Investigation of the Neural Correlates of Emotional Autobiographical Recollection

Recollection of emotional autobiographical memories (AMs) is important to healthy cognitive and affective functioning 1 - remembering positive AMs is associated with increased personal well-being and self-esteem 2, whereas remembering and ruminating on negative AMs may lead to affective disorders 3. Although significant progress has been made in understanding the brain mechanisms underlying AM retrieval in general (reviewed in 4, 5), less is known about the effect of emotion on the subjective re-experience of AMs and the associated neural correlates. This is in part due to the fact that, unlike the investigations of the emotion effect on memory for laboratory-based microevents (reviewed in 6, 7-9), often times AM studies do not have a clear focus on the emotional aspects of remembering personal events (but see 10). Here, we present a protocol that allows investigation of the neural correlates of recollecting emotional AMs using functional magnetic resonance imaging (fMRI). Cues for these memories are collected prior to scanning by means of an autobiographical memory questionnaire (AMQ), therefore allowing for proper selection of emotional AMs based on their phenomenological properties (i.e., intensity, vividness, personal significance). This protocol can be used in healthy and clinical populations alike.

We present a protocol that allows investigation of the neural correlates of recollecting emotional autobiographical memories, using functional magnetic resonance imaging. This protocol can be used with both healthy and clinical participants.

Recollection of emotional autobiographical memories (AMs) is important to healthy cognitive and affective functioning 1 - remembering positive AMs is ...

Neuroscience

Brain Imaging Investigation of the Neural Correlates of Emotion Regulation

The ability to control/regulate emotions is an important coping mechanism in the face of emotionally stressful situations. Although significant progress has been made in understanding conscious/deliberate emotion regulation (ER), less is known about non-conscious/automatic ER and the associated neural correlates. This is in part due to the problems inherent in the unitary concepts of automatic and conscious processing1. Here, we present a protocol that allows investigation of the neural correlates of both deliberate and automatic ER using functional magnetic resonance imaging (fMRI). This protocol allows new avenues of inquiry into various aspects of ER. For instance, the experimental design allows manipulation of the goal to regulate emotion (conscious vs. non-conscious), as well as the intensity of the emotional challenge (high vs. low). Moreover, it allows investigation of both immediate (emotion perception) and long-term effects (emotional memory) of ER strategies on emotion processing. Therefore, this protocol may contribute to better understanding of the neural mechanisms of emotion regulation in healthy behaviour, and to gaining insight into possible causes of deficits in depression and anxiety disorders in which emotion dysregulation is often among the core debilitating features.

We present a protocol that allows investigation of the neural correlates of deliberate and automatic emotion regulation, using functional magnetic resonance imaging. This protocol can be used in healthy participants, both young and older, as well as in clinical patients.

The ability to control/regulate emotions is an important coping mechanism in the face of emotionally stressful situations. Although significant progress ...

Brain Imaging Investigation of the Memory-Enhancing Effect of Emotion

Emotional events tend to be better remembered than non-emotional events1,2. One goal of cognitive and affective neuroscientists is 
to understand the neural mechanisms underlying this enhancing effect of emotion on memory. A method that has proven particularly influential in the 
investigation of the memory-enhancing effect of emotion is the so-called subsequent memory paradigm (SMP). This method was originally used to investigate the 
neural correlates of non-emotional memories3, and more recently we and others also applied it successfully to studies of emotional memory (reviewed in4, 5-7). 
Here, we describe a protocol that allows investigation of the neural correlates of the memory-enhancing effect of emotion using the SMP in conjunction with 
event-related functional magnetic resonance imaging (fMRI). An important feature of the SMP is that it allows separation of brain activity specifically 
associated with memory from more general activity associated with perception. Moreover, in the context of investigating the impact of emotional stimuli, 
SMP allows identification of brain regions whose activity is susceptible to emotional modulation of both general/perceptual and memory-specific processing. 
This protocol can be used in healthy subjects8-15, as well as in clinical patients where there are alterations in the neural correlates of emotion perception 
and biases in remembering emotional events, such as those suffering from depression and post-traumatic stress disorder (PTSD)16, 17.

We present a protocol that uses functional magnetic resonance imaging to investigate the neural correlates of the memory-enhancing effect of emotion. This protocol allows identification of brain activity specifically linked to memory-related processing, contrary to more general perceptual processing, and can be used with healthy and clinical populations.

Emotional events tend to be better remembered than non-emotional events1,2. One goal of cognitive and affective neuroscientists is 
to understand the ...

Brain Imaging Investigation of the Impairing Effect of Emotion on Cognition

Emotions can impact cognition by exerting both enhancing (e.g., better memory for emotional events) and impairing (e.g., increased emotional distractibility) effects (reviewed in 1). Complementing our recent protocol 2 describing a method that allows investigation of the neural correlates of the memory-enhancing effect of emotion (see also 1, 3-5), here we present a protocol that allows investigation of the neural correlates of the detrimental impact of emotion on cognition. The main feature of this method is that it allows identification of reciprocal modulations between activity in a ventral neural system, involved in 'hot' emotion processing (HotEmo system), and a dorsal system, involved in higher-level 'cold' cognitive/executive processing (ColdEx system), which are linked to cognitive performance and to individual variations in behavior (reviewed in 1). Since its initial introduction 6, this design has proven particularly versatile and influential in the elucidation of various aspects concerning the neural correlates of the detrimental impact of emotional distraction on cognition, with a focus on working memory (WM), and of coping with such distraction 7,11, in both healthy 8-11 and clinical participants 12-14.

We present a protocol that allows investigation of the neural mechanisms mediating the detrimental impact of emotion on cognition, using functional magnetic resonance imaging. This protocol can be used with both healthy and clinical participants.

Emotions can impact cognition by exerting both enhancing (e.g., better memory for emotional events) and impairing (e.g., increased emotional ...

The Emotional Stroop Task: Assessing Cognitive Performance under Exposure to Emotional Content

The emotional Stroop effect (ESE) is the result of longer naming latencies to ink colors of emotion words than to ink colors of neutral words. The difference shows that people are affected by the emotional content conveyed by the carrier words even though they are irrelevant to the color-naming task at hand. The ESE has been widely deployed with patient populations, as well as with non-selected populations, because the emotion words can be selected to match the tested pathology. The ESE is a powerful tool, yet it is vulnerable to various threats to its validity. This report refers to potential sources of confounding and includes a modal experiment that provides the means to control for them. The most prevalent threat to the validity of existing ESE studies is sustained effects and habituation wrought about by repeated exposure to emotion stimuli. Consequently, the order of exposure to emotion and neutral stimuli is of utmost importance. We show that in the standard design, only one specific order produces the ESE.

The emotional Stroop effect (ESE) is the result of longer naming latencies to ink colors of emotion words than those of neutral words. This report refers to potential sources of confounding and includes a modal experiment that provides the means to control for them.

The emotional Stroop effect (ESE) is the result of longer naming latencies to ink colors of emotion words than to ink colors of neutral words. The ...

Conscious and Non-conscious Representations of Emotional Faces in Asperger's Syndrome

Several neuroimaging studies have suggested that the low spatial frequency content in an emotional face mainly activates the amygdala, pulvinar, and superior colliculus especially with fearful faces1-3. These regions constitute the limbic structure in non-conscious perception of emotions and modulate cortical activity either directly or indirectly2. In contrast, the conscious representation of emotions is more pronounced in the anterior cingulate, prefrontal cortex, and somatosensory cortex for directing voluntary attention to details in faces3,4. Asperger&#39;s syndrome (AS)5,6 represents an atypical mental disturbance that affects sensory, affective and communicative abilities, without interfering with normal linguistic skills and intellectual ability. Several studies have found that functional deficits in the neural circuitry important for facial emotion recognition can partly explain social communication failure in patients with AS7-9. In order to clarify the interplay between conscious and non-conscious representations of emotional faces in AS, an EEG experimental protocol is designed with two tasks involving emotionality evaluation of either photograph or line-drawing faces. A pilot study is introduced for selecting face stimuli that minimize the differences in reaction times and scores assigned to facial emotions between the pretested patients with AS and IQ/gender-matched healthy controls. Information from the pretested patients was used to develop the scoring system used for the emotionality evaluation. Research into facial emotions and visual stimuli with different spatial frequency contents has reached discrepant findings depending on the demographic characteristics of participants and task demands2. The experimental protocol is intended to clarify deficits in patients with AS in processing emotional faces when compared with healthy controls by controlling for factors unrelated to recognition of facial emotions, such as task difficulty, IQ and gender.

An EEG experimental protocol is designed to clarify the interplay between conscious and non-conscious representations of emotional faces in patients with Asperger&#39;s syndrome. The technique suggests that patients with Asperger&#39;s syndrome have deficits in non-conscious representation of emotional faces, but have comparable performance in conscious representation with healthy controls.

Several neuroimaging studies have suggested that the low spatial frequency content in an emotional face mainly activates the amygdala, pulvinar, and ...

Correlating Behavioral Responses to fMRI Signals from Human Prefrontal Cortex: Examining Cognitive Processes Using Task Analysis

The aim of this methods paper is to describe how to implement a neuroimaging technique to examine complementary brain processes engaged by two similar tasks. Participants' behavior during task performance in an fMRI scanner can then be correlated to the brain activity using the blood-oxygen-level-dependent signal. We measure behavior to be able to sort correct trials, where the subject performed the task correctly and then be able to examine the brain signals related to correct performance. Conversely, if subjects do not perform the task correctly, and these trials are included in the same analysis with the correct trials we would introduce trials that were not only for correct performance. Thus, in many cases these errors can be used themselves to then correlate brain activity to them. We describe two complementary tasks that are used in our lab to examine the brain during suppression of an automatic responses: the stroop1 and anti-saccade tasks. The emotional stroop paradigm instructs participants to either report the superimposed emotional 'word' across the affective faces or the facial 'expressions' of the face stimuli1,2. When the word and the facial expression refer to different emotions, a conflict between what must be said and what is automatically read occurs. The participant has to resolve the conflict between two simultaneously competing processes of word reading and facial expression. Our urge to read out a word leads to strong 'stimulus-response (SR)' associations; hence inhibiting these strong SR's is difficult and participants are prone to making errors. Overcoming this conflict and directing attention away from the face or the word requires the subject to inhibit bottom up processes which typically directs attention to the more salient stimulus. Similarly, in the anti-saccade task3,4,5,6, where an instruction cue is used to direct only attention to a peripheral stimulus location but then the eye movement is made to the mirror opposite position. Yet again we measure behavior by recording the eye movements of participants which allows for the sorting of the behavioral responses into correct and error trials7 which then can be correlated to brain activity. Neuroimaging now allows researchers to measure different behaviors of correct and error trials that are indicative of different cognitive processes and pinpoint the different neural networks involved.

The goal of our research is to correlate behavior to brain activity. Accurate behavioral measures and imaging techniques allow us to elucidate brain-behavior relationships.

The aim of this methods paper is to describe how to implement a neuroimaging technique to examine complementary brain processes engaged by two similar ...

Assessing Binocular Central Visual Field and Binocular Eye Movements in a Dichoptic Viewing Condition

Macular degeneration typically results in heterogeneous binocular central visual defects. Currently available approaches to assess central visual field, like the microperimetry, can test only one eye at a time. Therefore, they cannot explain how the defects in each eye affect the binocular interaction and real-world function. Dichoptic stimulus presentation with a gaze-controlled system could provide a reliable measure of monocular/binocular visual fields. However, dichoptic stimulus presentation and simultaneous eye-tracking are challenging because optical devices of instruments that present stimulus dichoptically (e.g., haploscope) always interfere with eye-trackers (e.g., infrared video-based eye-trackers). Therefore, the goals were 1) to develop a method for dichoptic stimulus presentation with simultaneous eye-tracking, using 3D-shutter glasses and 3D-ready monitors, that is not affected by interference and 2) to use this method to develop a protocol for assessing central visual field in subjects with central vision loss. The results showed that this setup provides a practical solution for reliably measuring eye-movements in dichoptic viewing condition. In addition, it was also demonstrated that this method can assess gaze-controlled binocular central visual field in subjects with central vision loss.

Presented here is a protocol for assessing binocular eye movements and gaze-controlled central visual field screening in participants with central vision loss.

Macular degeneration typically results in heterogeneous binocular central visual defects. Currently available approaches to assess central visual field, ...

The Split Brain

Source: Laboratories of Jonas T. Kaplan and Sarah I. Gimbel&#8212;University of Southern California
The study of how damage to the brain affects cognitive functioning has historically been one of the most important tools for cognitive neuroscience. While the brain is one of the most well protected parts of the body, there are many events that can affect the functioning of the brain. Vascular issues, tumors, degenerative diseases, infections, blunt force traumas, and neurosurgery are just some of the underlying causes of brain damage, all of which may produce different patterns of tissue damage that affect brain functioning in different ways.
The history of neuropsychology is marked by several well-known cases that led to advances in the understanding of the brain. For instance, in 1861 Paul Broca observed how damage to the left frontal lobe resulted in aphasia, an acquired language disorder. As another example, a great deal about memory has been learned from patients with amnesia, such as the famous case of Henry Molaison, known for many years in the neuropsychology literature as &#34;H.M.,&#34; whose temporal lobe surgery led to a profound deficit in forming certain kinds of new memories.
While the observation and testing of patients with focal brain damage has provided neuroscience with insight into the functioning of the brain, great care must be taken in designing tests to reveal the specific nature of the deficit. Also, because the brain is a complex network of interconnected neurons, damage to one brain region can affect functioning in regions far away from the damage. To demonstrate how brain damage can affect connections among brain regions, this video examines the case of the so-called split brain.
The corpus callosum is a large bundle of fibers that connects the left and right hemispheres of the brain. It is one of the largest white matter tracts in the brain and can be easily recognized on a sagittal view of the midline of the brain. In the 1960s, neurosurgeons discovered that cutting the corpus callosum could be a successful treatment for certain kinds of epilepsy, which involves uncontrollable neural activity spreading through the brain. People who underwent the split-brain operation had their two hemispheres surgically separated, such that the left and right hemispheres were no longer able to communicate. This condition allowed experimenters to probe the functions of the left and right hemisphere independently, to learn about the relative abilities, and about the nature of communication between them.
This video demonstrates how to test a split-brain patient to reveal some of the differences between the two hemispheres of the brain and to see some dramatic consequences of such a disconnection. The original versions of these experiments were developed by Michael Gazzaniga and colleagues1, 2 and later were elaborated upon by others;3 the version presented here incorporates more recent modernizations of the methodology.

Testing Cognitive Abilities in Split-brain Patients Using Visual Stimuli

Source: Laboratories of Jonas T. Kaplan and Sarah I. Gimbel&#8212;University of Southern California
The study of how damage to the brain affects cognitive ...

Central and Divided Visual Field Presentation of Emotional Images to Measure Hemispheric Differences in Motivated Attention

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