This research was supported by start-up funds to FD. KS was supported by a summer studentship from the Alberta Heritage Foundation for Medical Research. FD was supported by a Young Investigator Award from the National Alliance for Research on Schizophrenia and Depression, and a CPRF Award from the Canadian Psychiatric Research Foundation. The authors wish to thank Peter Seres for assistance with data collection and Kristina Suen for assistance with data analysis.

1. Stimuli, Task Design, and Experimental Protocol
Our stimuli are created using Poser 7.0 (<a href="http://poser.smithmicro.com/poser.html">http://poser.smithmicro.com/poser.html</a>), and they are presented using CIGAL (<a href="http://www.nitrc.org/projects/cigal/">http://www.nitrc.org/projects/cigal/</a>).
<ol>
<li>The task consists of a series of ten-second animated videos of non-verbal guest-host interactions in a business setting. The subject views the guest being greeted by a host (social interaction condition) or a cardboard cut-out of a host (no social interaction/control condition).</li>
<li>The host may display behaviours that are inviting to further social interaction (approach condition), or behaviours that may indicate lack of interest in further interaction (avoid condition).</li>
<li>In addition to this basic manipulation of the type of behaviour displayed by the host, other manipulations may also be included. For instance, in some of the trials (typically half) the characters may shake hands, as part of the greeting protocol, whereas in others they do nothing. This manipulation allows investigation of the effect of formal physical touch on behaviour4, which may also be expected to have different significance depending on the cultural background of the viewer (e.g., Western vs. East-Asian).</li>
<li>Other manipulation may involve the change of the viewer&#x2019;s perspective from personal (Me) to impersonal (Other). This manipulation aims at tapping into neural networks associated with self-referential processing5, and allows identification of responses that are modulated by personal engagement6,7(e.g., exacerbation of the impact of avoid behaviour, if taken personally). The alternation between these two perspectives can be cued at the beginning of each trial. </li>
<li>Videos are followed by rating screens that are asking the subject to rate the host on competence, trustworthiness, and interest in doing business on a 5-point Likert scale (0 = not at all / 4 = very much); these ratings should be counterbalanced across trials, to avoid order effects. </li>
<li>Characters in videos are counterbalanced for displayed behaviour (approach vs. avoid), ethnic background (Caucasian vs. Non-Caucasian), shirt colour, and hairstyle. Basic aspects that may influence social interactions (e.g., attractiveness) should also be controlled for (e.g., by off-line ratings of the hosts), to ensure that there are no systematic differences between trial categories, and thus avoid possible confounds (e.g., if hosts displaying avoid behaviour also have overall lower attractiveness scores). Finally, given the evidence that interactions with female-hosts are more effective in influencing decisions (e.g., financial) 4, in our current study all hosts were females, but the gender of the hosts can also be counterbalanced across trials &#x2013; e.g., 50% females vs. 50% males.</li>
<li>The experiment is split into runs/blocks of trials, to allow participants time to rest, and avoid massive data loss in case of equipment malfunction. Also, to avoid biased data loss, ideally the conditions/trials should be equally represented in each block, according to each manipulation (e.g., social interaction, gender, shake/no-shake). Run order is also counterbalanced between participants. Each run begins with six seconds of a fixation, to allow stabilisation of the MR signal. An inter-trial interval of 8 seconds follows each movie-trial and ends each run/block.</li>
<li>It should be noted that, while compared to experimental designs involving static stimuli the present design has increased ecological validity in identifying neural correlates of social cognition, this approach also poses limitations and challenges. One such challenge is posed by the need to maintain the "background" aspects (e.g., the environment where social interactions occur or the non-relevant aspects of behaviour) as constant as possible, in the context of manipulating the behavioural variables of interest (e.g., gestures distinguishing the targeted social interactions), which may be difficult to accomplish in conditions where dynamic stimuli are used. Nevertheless, we believe that the present approach reaches a reasonable trade-off between the goal of increasing ecological validity of stimuli used in social neuroscience studies and the constraints associated with the involvement of brain imaging tools that require reasonable control of the experimental manipulations to allow valid inferences about the neural correlates of targeted behaviours.</li>
</ol>
2. Preparing the Subject for the Scan
Subjects are typically recruited on the basis of their age, health, first language, and individual risk factors for MRI scanning, such as metallic joint replacements. However, depending of the purpose of the study, other factors may also be considered, including race/ethnic background, socio-economic status, and history of drug use. All subjects provide written informed consent prior to running the experimental protocol, which is approved by an Ethics Board.
Prior to Entering the scanning room
<ol>
<li>On the day of scanning, participants are asked to complete questionnaires that assess their current state of mind, to ensure that they are not overly anxious or depressed before the experiment 8, 9. These assessments can also be used in conjunction with fMRI data, to investigate how the emotional state at the time of scanning may influence the participants&#x2019; responses. Also, in conjunction with post-scanning assessments, these initial evaluations can be used to make sure that the participants&#x2019; overall emotional state does not change dramatically as a result of their participation in the experiment. Finally, other behavioural/personality assessments can also be made, to further investigate how individual variations in particular aspects of personality that influence responses in social contexts (e.g., social anxiety, trustworthiness) may influence participants&#x2019; responses during the study 10, 11.</li> 
<li>Prior to the scan, the participant is informed in detail of the scanning procedures, and is given specific instructions for the behavioural task (described below). To avoid discomfort and increased familiarity with the task, the participant is also given an abbreviated practice run for the task.</li>
</ol>
Entering the scanning room
<ol start="3">
<li>The subject is instructed to lie supine on the scanning bed, with additional cushioning for the head, to ensure comfort during the scan and to minimize movement. To further minimize head movement, the non-adhesive side of a length of tape may be wrapped lightly around the subject&#x2019;s forehead. If preferred, cushioning may also be placed under the raised knees of the subject, to reduce lower back muscular tension.</li>
<li>Subjects are given ear protection (ear plugs) as well as isolation headphones to communicate with the experimenter during the MRI scan.</li>
<li>The subject&#x2019;s right hand is positioned comfortably on the response box, thus allowing the left hand to be used for support or for other measurements (e.g., skin conductance responses). An emergency stop button should also be placed nearby, so that the subject may indicate any urgent need to stop the scanner.</li>
<li>Before starting data collection, it is critical to make sure that the subject can see the screen projection clearly, for stimulus presentation, and that the response buttons work properly.</li>
</ol>
3. Data Recording and Processing
Scanning Parameters 
We collected MRI data using a 1.5 Tesla Siemens Sonata scanner for MRI recordings. Our anatomical images were 3D MPRAGE anatomical series (repetition time, TR = 1600 ms; echo time TE = 3.82 ms; number of slices = 112; voxel size = 1 x 1 x 1mm), and functional images consisted of series of 28 functional slices (voxel size = 4x4x4 mm), acquired axially using an echoplanar sequence (TR = 2000 ms; TE = 40 ms; field of view FOV = 256 x 256mm), thus allowing for full-brain coverage.
Data Analysis
We use Statistical Parametric Mapping (SPM2/SPM5) in combination with in-house Matlab-based tools. Pre-processing involves typical steps: quality assurance, TR alignment, motion correction, co-registration, normalization, and smoothing (8 mm&sup3; kernel) 12. 
<ol>
<li>Data analysis combines voxel-wise and region of interest (ROI) approaches to compare brain activity associated with the conditions of interest (e.g., social interaction vs. non-social interaction).</li> 
<li>Whole-brain voxel-wise analyses produce statistical maps that identify larger networks of brain regions associated with processing that underlies the assessment of social interactions, and ROI analyses allows targeted investigation of the response in specific brain-regions, which are a priori identified as being part of the social cognition network (Figure 1A). ROI analyses are also used to extract the fMRI signal for illustration purposes (Figure 1B). We used an intensity threshold of p=0.001 and an extent threshold of 10 contiguous voxels. In addition to these typical methods involved in data analysis, other ways of analyzing data may also be employed as complementary approaches in studies investigating the neural correlates of social cognition 13, 14.</li>
<li>Finally, correlations of brain imaging data with behavioural data (e.g., trustworthiness ratings) and/or scores indexing personality measures (e.g., trait anxiety) can also be performed, to investigate how brain activity co-varies with individual differences in behaviour and personality.</li>
</ol>
4. Representative Results
<img src="/files/ftp_upload/2379/2379fig1.jpg" alt="Figure 1"/> 
Figure 1. Increased activity in the social cognition network in response to observing social interactions. Comparison of social interaction vs. no-interaction/control trials revealed activity in typical social cognition brain regions, including the superior temporal sulcus (STS, a), the lateral and medial prefrontal cortex (mPFC, b &amp; d, respectively), and the amygdala (AMY, c). The "activation maps" are superimposed on high resolution brain images displayed in lateral (left- and right-side panels) and coronal (middle panel) views; the color bars indicate the gradient of t values of the activation maps (based on data from 15 participants), reflecting brain activity time-locked to the onsets of approach/avoid behaviours. The line graphs illustrate the time courses of the fMRI signal, extracted from functional ROIs for each trial type and TR (1 TR = 2 seconds). L = Left; R = Right.

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No conflicts of interest declared.

The experimental design introduced here allows investigation of the neural correlates of observing and interpreting body language. This design has the potential to advance our knowledge concerning brain mechanisms involved in social interactions, and to extend theoretical models of how we combine perception of different types of body language or social concepts such as trustworthiness to make decisions in interactive social environments 3. Such knowledge can be applied in a variety of personal and business settings, and can improve our understanding of clinical deficits in social interaction. The success of this design depends on proper task manipulation, involvement of ecologically valid stimuli, and careful data collection

brain imaging investigation of the neural correlates of observing virtual social interactions

The ability to gauge social interactions is crucial in the assessment of others&#x2019; intentions. Factors such as facial expressions and body language affect our decisions in personal and professional life alike 1. These "friend or foe" judgements are often based on first impressions, which in turn may affect our decisions to "approach or avoid". Previous studies investigating the neural correlates of social cognition tended to use static facial stimuli 2. Here, we illustrate an experimental design in which whole-body animated characters were used in conjunction with functional magnetic resonance imaging (fMRI) recordings. Fifteen participants were presented with short movie-clips of guest-host interactions in a business setting, while fMRI data were recorded; at the end of each movie, participants also provided ratings of the host behaviour. This design mimics more closely real-life situations, and hence may contribute to better understanding of the neural mechanisms of social interactions in healthy behaviour, and to gaining insight into possible causes of deficits in social behaviour in such clinical conditions as social anxiety and autism 3.

Watch this Scientific Journal Video about Brain Imaging Investigation of the Neural Correlates of Observing Virtual Social Interactions at JoVE.com

Brain Imaging Investigation of the Neural Correlates of Observing Virtual Social Interactions

This article demonstrates an experimental design in which whole-body animated characters are used in conjunction with functional magnetic resonance imaging (fMRI) to investigate the neural correlates of observing virtual social interactions.

The ability to gauge social interactions is crucial in the assessment of others&#x2019; intentions. Factors such as facial expressions and body language ...

brain-imaging-investigation-neural-correlates-observing-virtual

Nanyang Technological University

Research

JoVE Journal

Neuroscience

11.5K Views.  University of Alberta. This article demonstrates an experimental design in which whole-body animated characters are used in conjunction with functional magnetic resonance imaging (fMRI) to investigate the neural correlates of observing virtual social interactions.

Video: Brain Imaging Investigation of the Neural Correlates of Observing Virtual Social Interactions

Combining Behavioral Endocrinology and Experimental Economics: Testosterone and Social Decision Making

Behavioral endocrinological research in humans as well as in animals suggests that testosterone plays a key role in social interactions. Studies in rodents have shown a direct link between testosterone and aggressive behavior1 and folk wisdom adapts these findings to humans, suggesting that testosterone induces antisocial, egoistic or even aggressive behavior2. However, many researchers doubt a direct testosterone-aggression link in humans, arguing instead that testosterone is primarily involved in status-related behavior3,4. As a high status can also be achieved by aggressive and antisocial means it can be difficult to distinguish between anti-social and status seeking behavior.
We therefore set up an experimental environment, in which status can only be achieved by prosocial means. In a double-blind and placebo-controlled experiment, we administered a single sublingual dose of 0.5 mg of testosterone (with a hydroxypropyl-&beta;-cyclodextrin carrier) to 121 women and investigated their social interaction behavior in an economic bargaining paradigm. Real monetary incentives are at stake in this paradigm; every player A receives a certain amount of money and has to make an offer to another player B on how to share the money. If B accepts, she gets what was offered and player A keeps the rest. If B refuses the offer, nobody gets anything. A status seeking player A is expected to avoid being rejected by behaving in a prosocial way, i.e. by making higher offers.
The results show that if expectations about the hormone are controlled for, testosterone administration leads to a significant increase in fair bargaining offers compared to placebo. The role of expectations is reflected in the fact that subjects who report that they believe to have received testosterone make lower offers than those who say they believe that they were treated with a placebo. These findings suggest that the experimental economics approach is sensitive for detecting neurobiological effects as subtle as those achieved by administration of hormones. Moreover, the findings point towards the importance of both psychosocial as well as neuroendocrine factors in determining the influence of testosterone on human social behavior.

The procedure described in this protocol shows that testosterone administration and folk beliefs about testosterone may be associated with directly opposed social behaviors.

Behavioral endocrinological research in humans as well as in animals suggests that testosterone plays a key role in social interactions. Studies in ...

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 ...

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 ...

Extinction Training During the Reconsolidation Window Prevents Recovery of Fear

Fear is maladaptive when it persists long after circumstances have become safe. It is therefore crucial to develop an approach that persistently prevents the return of fear. Pavlovian fear-conditioning paradigms are commonly employed to create a controlled, novel fear association in the laboratory. After pairing an innocuous stimulus (conditioned stimulus, CS) with an aversive outcome (unconditioned stimulus, US) we can elicit a fear response (conditioned response, or CR) by presenting just the stimulus alone1,2 . Once fear is acquired, it can be diminished using extinction training, whereby the conditioned stimulus is repeatedly presented without the aversive outcome until fear is no longer expressed3. This inhibitory learning creates a new, safe representation for the CS, which competes for expression with the original fear memory4. Although extinction is effective at inhibiting fear, it is not permanent. Fear can spontaneously recover with the passage of time. Exposure to stress or returning to the context of initial learning can also cause fear to resurface3,4.
Our protocol addresses the transient nature of extinction by targeting the reconsolidation window to modify emotional memory in a more permanent manner. Ample evidence suggests that reactivating a consolidated memory returns it to a labile state, during which the memory is again susceptible to interference5-9. This window of opportunity appears to open shortly after reactivation and close approximately 6hrs later5,11,16, although this may vary depending on the strength and age of the memory15. By allowing new information to incorporate into the original memory trace, this memory may be updated as it reconsolidates10,11. Studies involving non-human animals have successfully blocked the expression of fear memory by introducing pharmacological manipulations within the reconsolidation window, however, most agents used are either toxic to humans or show equivocal effects when used in human studies12-14. Our protocol addresses these challenges by offering an effective, yet non-invasive, behavioral manipulation that is safe for humans.
By prompting fear memory retrieval prior to extinction, we essentially trigger the reconsolidation process, allowing new safety information (i.e., extinction) to be incorporated while the fear memory is still susceptible to interference. A recent study employing this behavioral manipulation in rats has successfully blocked fear memory using these temporal parameters11. Additional studies in humans have demonstrated that introducing new information after the retrieval of previously consolidated motor16, episodic17, or declarative18 memories leads to interference with the original memory trace14. We outline below a novel protocol used to block fear recovery in humans.

Conditioned fear can be diminished through an inhibitory process called extinction, but can resurface under conditions such as the passage of time or exposure to stress. Our protocol presents a novel way of preventing fear recovery by introducing extinction during the reconsolidation window (the re-storage phase of a reactivated memory).

Fear is maladaptive when it persists long after circumstances have become safe. It is therefore crucial to develop an approach that persistently prevents ...

Co-analysis of Brain Structure and Function using fMRI and Diffusion-weighted Imaging

The study of complex computational systems is facilitated by network maps, such as circuit diagrams. Such mapping is particularly informative when studying the brain, as the functional role that a brain area fulfills may be largely defined by its connections to other brain areas. In this report, we describe a novel, non-invasive approach for relating brain structure and function using magnetic resonance imaging (MRI). This approach, a combination of structural imaging of long-range fiber connections and functional imaging data, is illustrated in two distinct cognitive domains, visual attention and face perception. Structural imaging is performed with diffusion-weighted imaging (DWI) and fiber tractography, which track the diffusion of water molecules along white-matter fiber tracts in the brain (Figure 1). By visualizing these fiber tracts, we are able to investigate the long-range connective architecture of the brain. The results compare favorably with one of the most widely-used techniques in DWI, diffusion tensor imaging (DTI). DTI is unable to resolve complex configurations of fiber tracts, limiting its utility for constructing detailed, anatomically-informed models of brain function. In contrast, our analyses reproduce known neuroanatomy with precision and accuracy. This advantage is partly due to data acquisition procedures: while many DTI protocols measure diffusion in a small number of directions (e.g., 6 or 12), we employ a diffusion spectrum imaging (DSI)1, 2 protocol which assesses diffusion in 257 directions and at a range of magnetic gradient strengths. Moreover, DSI data allow us to use more sophisticated methods for reconstructing acquired data. In two experiments (visual attention and face perception), tractography reveals that co-active areas of the human brain are anatomically connected, supporting extant hypotheses that they form functional networks. DWI allows us to create a "circuit diagram" and reproduce it on an individual-subject basis, for the purpose of monitoring task-relevant brain activity in networks of interest.

We describe a novel approach for simultaneous analysis of brain function and structure using magnetic resonance imaging (MRI). We assess brain structure with high-resolution diffusion-weighted imaging and white-matter fiber tractography. Unlike standard structural MRI, these techniques allow us to directly relate anatomical connectivity to functional properties of brain networks.

The study of complex computational systems is facilitated by network maps, such as circuit diagrams. Such mapping is particularly informative when ...

Peering into the Dynamics of Social Interactions: Measuring Play Fighting in Rats

Play fighting in the rat involves attack and defense of the nape of the neck, which if contacted, is gently nuzzled with the snout. Because the movements of one animal are countered by the actions of its partner, play fighting is a complex, dynamic interaction. This dynamic complexity raises methodological problems about what to score for experimental studies. We present a scoring schema that is sensitive to the correlated nature of the actions performed. The frequency of play fighting can be measured by counting the number of playful nape attacks occurring per unit time. However, playful defense, as it can only occur in response to attack, is necessarily a contingent measure that is best measured as a percentage (#attacks defended/total # attacks X 100%). How a particular attack is defended against can involve one of several tactics, and these are contingent on defense having taken place; consequently, the type of defense is also best expressed contingently as a percentage. Two experiments illustrate how these measurements can be used to detect the effect of brain damage on play fighting even when there is no effect on overall playfulness. That is, the schema presented here is designed to detect and evaluate changes in the content of play following an experimental treatment.

Play fighting in the rat involves attack and defense of the nape of the neck, which if contacted, is gently nuzzled with the snout. Because the movements of one animal are countered by the actions of its partner, play fighting is a complex, dynamic interaction. This dynamic complexity raises methodological problems about what to score for experimental studies. We present a scoring schema that is sensitive to the correlated nature of the actions performed. Two experiments illustrate how these measurements can be used to detect the effect of brain damage on play fighting even when there is no effect on overall playfulness. That is, the schema presented here is designed to detect and evaluate changes in the content of play following an experimental treatment.

Play fighting in the rat involves attack and defense of the nape of the neck, which if contacted, is gently nuzzled with the snout. Because the movements ...

A Computer-assisted Multi-electrode Patch-clamp System

The patch-clamp technique is today the most well-established method for recording electrical activity from individual neurons or their subcellular compartments. Nevertheless, achieving stable recordings, even from individual cells, remains a time-consuming procedure of considerable complexity. Automation of many steps in conjunction with efficient information display can greatly assist experimentalists in performing a larger number of recordings with greater reliability and in less time. In order to achieve large-scale recordings we concluded the most efficient approach is not to fully automatize the process but to simplify the experimental steps and reduce the chances of human error while efficiently incorporating the experimenter's experience and visual feedback. With these goals in mind we developed a computer-assisted system which centralizes all the controls necessary for a multi-electrode patch-clamp experiment in a single interface, a commercially available wireless gamepad, while displaying experiment related information and guidance cues on the computer screen. Here we describe the different components of the system which allowed us to reduce the time required for achieving the recording configuration and substantially increase the chances of successfully recording large numbers of neurons simultaneously.

Multi-electrode patch-clamp recordings constitute a complex task. Here we show how, by automating of many of the experimental steps, it is possible to accelerate the process leading to qualitative improvement in performance and number of recordings.

The patch-clamp technique is today the most  well-established method for recording electrical activity from individual  neurons or their subcellular ...

Imaging Neural Activity in the Primary Somatosensory Cortex Using Thy1-GCaMP6s Transgenic Mice

The mammalian brain exhibits marked symmetry across the sagittal plane. However, detailed description of neural dynamics in symmetric brain regions in adult mammalian animals remains elusive. In this study, we describe an experimental procedure for measuring calcium dynamics through dual optical windows above bilateral primary somatosensory corticies (S1) in Thy1-GCaMP6s transgenic mice using 2-photon (2P) microscopy. This method enables recordings and quantifications of neural activity in bilateral mouse brain regions one at a time in the same experiment for a prolonged period in vivo. Key aspects of this method, which can be completed within an hour, include minimally invasive surgery procedures for creating dual optical windows, and the use of 2P imaging. Although we only demonstrate the technique in the S1 area, the method can be applied to other regions of the living brain facilitating the elucidation of structural and functional complexities of brain neural networks.

Imaging Neural Activity in the Primary Somatosensory Cortex Using Thy1-GCaMP6s Transgenic Mice

We describe an experimental procedure for measuring neuronal activity through dual optical windows above bilateral primary somatosensory corticies (S1) in Thy1-GCaMP6s transgenic mice using 2-photon (2P) microscopy in vivo.

The mammalian brain exhibits marked symmetry across the sagittal plane. However, detailed description of neural dynamics in symmetric brain regions in ...