לוח שנה משולב

Humans and animals tend to behave differently when learning from rewarding or aversive feedback, and the amygdala is hypothesized to play a role in these differences. Here, we studied neural mechanisms of learning and decision making in reward and punishment, namely post-stimulus rehearsal, balancing of exploration and exploitation and generalization. To study post-stimulus rehearsal in amygdala neurons, we investigated spike-sequences across simultaneously recorded neurons of non-human primates, while they learned to discriminate between aversive and pleasant tone-odor associations. We showed that valence specific sequences across amygdala neurons rehearsed the coding of the recent association, so they can serve as a coding mechanism that enhances memory formation by rehearsal of the recent association. Next, to examine neural coding of exploration under rewards and punishments, we recorded single neurons while human subjects were engaged in a probabilistic decision-making task with gain and loss conditions, and found more exploration when subjects tried to minimize their losses. We found two mechanisms of explorational choices: one is executed through firing rate of single neurons in the temporal cortex and amygdala and is shared across valence, and the other is executed by an increase in noise in amygdala neurons, and is specific to the loss condition. Finally, we found that over-generalization around a loss-conditioned tone was accompanied by a similar over response of amygdala neurons. Together, this work expands the knowledge of neural mechanisms that enhance learning and improves decision making, specifically in complex environments that include opportunities for rewards and risks for punishments.
Zoom link: https://weizmann.zoom.us/j/96622589021?pwd=Tkh1RWk0OFhaVFE0SW9KeU84Q1cvZz09

Meeting ID: 966 2258 9021
Password: 022196

Using mammalian skin as a model, Prof. Elaine Fuchs studies the remarkable properties
of tissue stem cells to replenish dying cells and repair wounds, and how the cells know
which tasks to perform and when. She explores how stem cells sense and communicate
with other cells in their environment. Aiming at advancing therapeutics, she dissects how
communication networks malfunction in inflammation, aging, and cancers.

Dipolar interactions are fundamentally different from the usual van der Waals forces in real gases. Besides its anisotropy the dipolar interaction is nonlocal and as such allows for self organized structure formation, like in many different fields of physics. Although the bosonic dipolar quantum liquid is very dilute, stable droplets and supersolids as well as honeycomb or labyrinth patterns can be formed due to the presence of quantum fluctuations beyond the mean field theory.