Evolúcia - Etológia - Neurobiológia

Devendra Singh

Glenn E. Weisfeld, Carol C. Weisfeld

Helen Fisher, Arthur Aron, Debra Mashek, Haifang Li, Greg Strong, Lucy L. Brown

Monica Maranesi,1 Alessandro Livi,2 Leonardo Fogassi,2 Giacomo Rizzolatti,1 and Luca Bonini1
1Istituto Italiano di Tecnologia (IIT), Brain Center for Social and Motor Cognition (BCSMC), 43125 Parma, Italy and 2University of Parma, Department of Neuroscience, 43125 Parma, Italy
A fundamental capacity of social animals consists in the predictive representation of upcoming events in the outside world, such as the actions of others. Here,wetested the activity of ventral premotor area F5 mirror neurons (MNs) while monkeys observed an experimenter performing (Action condition) or withholding (Inaction condition) a grasping action, which could be predicted on the basis of previously presented auditory instructions. Many of the recorded MNs discharged only during action observation (Action MNs), but one-third also encoded the experimenter’s withheld action (Inaction MNs). Interestingly, while most of ActionMNsexhibited reactive discharge during action observation, becoming active after the go signal, the majority of InactionMNsshowed predictive discharge.MNpopulation activity as a whole displayed an overall predictive activation pattern, becoming active, on average, 340msbefore the go signal. Furthermore,MNs became active earlier when the observed action was performed in the monkeys’ extrapersonal rather than peripersonal space, suggesting that context-based neural prediction of others’ actions plays different roles depending on the monkeys’ ability to interact with the
observed agent.

Susanne G Mueller, Peter Ng, Thomas Neylan, Scott Mackin, Owen Wolkowitz, Synthia Mellon, Xiaodan Yan, Janine Flory, Rachel Yehuda, Charles R. Marmar, Michael W. Weiner
Posttraumatic stress disorder (PTSD) is characterized by atrophy within the prefrontal-limbic network. Graph analysis was used to investigate to what degree atrophy in PTSD is associated with impaired structural connectivity within prefrontal limbic network (restricted) and how this affects the integration of the prefrontal limbic network with the rest of the brain (whole-brain). 85 male veterans (45 PTSD neg, 40 PTSD pos) underwent volumetric MRI on a 3T MR. Subfield volumes were obtained using a manual labeling scheme and cortical thickness measurements and subcortical volumes from FreeSurfer. Regression analysis was used to identify regions with volume loss. Graph analytical Toolbox (GAT) was used for graph-analysis. PTSD pos had a thinner rostral anterior cingulate and insular cortex but no hippocampal volume loss. PTSD was characterized by decreased nodal degree (orbitofrontal, anterior cingulate) and clustering coefficients (thalamus) but increased nodal betweenness (insula, orbitofrontal) and a reduced small world index in the whole brain analysis and by orbitofrontal and insular nodes with increased nodal degree, clustering coefficient and nodal betweenness in the restricted analysis. PTSD associated atrophy in the prefrontal-limbic network results in an increased structural connectivity within that network that negatively affected its integration with the rest of the brain.

Evolution and Pathology
Edited by
Martin Brune
Centre for Psychiatry and Psychotherapy, University of Bochum, Germany
Hedda Ribbert
Centre for Psychiatry and Psychotherapy, University of Bochum, Germany
Wulf Schiefenhovel
Human Ethology Group,Max-Planck-Society, Andechs
Centre for Human Sciences, University ofMunich, Germany