Past events

Navigation, the ability to reach a desired goal location, is a complex behavior that occurs in complex environments. It requires the animal to know its own location in the environment, but also be attentive to other things in the environment that could influence its route – such as the navigational goal or other alternative goals, landmarks and obstacles along the route, as well as other conspecifics it may encounter. Despite the complexity and richness of real-world navigation, most studies of the neural basis of navigation were done in small empty setups. During my PhD, I focused on how the hippocampus represents navigation in more naturalistic and dynamic scenarios. In my first PhD project I found a vectorial representation of spatial goals in the bat hippocampus, which could support goal-directed navigation. In my second PhD project I found that during dynamic ‘cross-overs’ between two bats, hippocampal neurons switched from representing the bat’s self-position to a conjunctive representation of position × distance to the other bat – an extremely rapid neuronal switch. Taken together, in my PhD I studied the neural basis of dynamic natural navigation by adding more naturalistic aspects of navigation – such as navigation to goals and collision-avoidance behavior – and this allowed me to reveal interesting and surprising new representations in the hippocampus. 

Aggression and dominance hierarchy are basic social behaviors that are essential for the survival and reproductive success of most mammalian species. Typically, they are displayed whenever conspecifics have to compete for limited resources, such as food, water, territory, or access to mates. As a result, and due to sexual selection, intra-sexual competition is higher in males compared to females as fertile females are a limited resource to males. Thus, males often express a higher level of aggression and are most likely to form a dominance hierarchy in a group. Therefore, most studies of the biological basis of intra-sexual aggression and dominance hierarchy have been focused on males. However, it has long been observed that females also compete with each other and can form dominant hierarchies. In this study, we aimed to investigate the role of OT+ PVN neurons in the aggression of wild-derived female mice by comparing them to males. Wild-derived mice were chosen for their higher levels of aggression compared to the lab mouse strains, which might have lost these behavioral traits due to artificial selection and socially restricted environment while in captivity. To manipulate OT+ PVN neurons, we established a wild OT:Cre mouse line by backcrossing wild-derived mice with transgenic lab mice and validated that its phenotype resembles the wild-derived mice. Using these novel wild-backcrossed OT:Cre (Wild-BX) mice, we found that OT+ PVN neurons of females are activated due to agonistic interaction. Next, we virally ablated, using Casp3, or activated, using DREADD, OT+ PVN neurons in wild-BX males and females, and performed a standard resident-intruder assay (RI) to examine territorial aggression towards same-sex adults and unfamiliar pups. We found that ablation of OT+ PVN neurons in wild-BX females reduces adult and pup-directed aggression and increases sniffing behavior. In contrast, activation of this neuronal population promotes aggressive behavior toward adults and pups and decrees sniffing behavior. In males, similar manipulations did not affect either of these aggressive or sniffing behaviors, except a weak impact on pup-directed aggression. Moreover, by examining group behavior in a semi-natural environment, we found that ablation of OT+ PVN neurons suppresses dominant hierarchy formation in groups of wild-BX females. In contrast, activation strengthened the hierarchy and increased agonistic behavior in the group. In males, in contrast to the RI, the OT+ PVN ablation delayed the formation of the hierarchy and increased the anxiety in the group, whereas activation weakened the hierarchy and increased pro-social behavior. These findings suggest that OT PVN neurons have a sexually-dimorphic effect in aggression and dominance hierarchy behaviors, and they emphasize the importance of investigating both sexes in ethologically-relevant animal models and social contexts, in the study of socially relevant neuromodulators. Zoom link: https://weizmann.zoom.us/j/96648920836?pwd=OXlvV0NPTHIrVHNLYUpvZ2lNTnJZdz09 Meeting ID: 966 4892 0836 Password: 248477

Making decisions, attending to certain items, and manipulating information in working memory are fundamental behaviors that rely on specific neural circuitry. Throughout my research I have contributed to understanding such behaviors in human and in nonhuman primates but found that despite tremendous advances in the field, we still lack a mechanistic understanding of what goes wrong in conditions such as dementia or autism. My long-term research goal is to determine the circuits that support cognitive behavior, in health and disease. In my talk, I present three key contributions I have made towards uncovering neuronal circuits for cognition in the macaque, an animal model whose neural circuitry affords unique insight into human brain function. First, I demonstrate the utility of rigorous psychophysical frameworks in determining the causal contribution of key brain regions to behavior in a perceptual decision-making task. Next, I describe how causal manipulations of brain areas involved in attentional control can be used to identify hitherto unknown areas and reveal new functional circuits in support of selective attention and object recognition. Finally, I show how computational analyses of population data reveal circuits within circuits with distinct roles in supporting working memory. I end the talk by presenting my future research directions and approach: to leverage my experience studying how we select from external information (from sensory signals) to investigate how we select from internal information (from information stored in visual working memory). By blending theory-driven experiments with large-scale electrophysiological recording and circuit-specific causal manipulations in behaving macaques, I aim to uncover how we select relevant information from working memory, and equally important, how we fail to do so when struck by disorders of executive or memory function.

Naturalistic experimental paradigms in neuroimaging arose from a pressure to test the validity of models we derive from highly controlled experiments in real-world contexts. In many cases, however, such efforts led to the realization that models developed under particular experimental manipulations failed to capture much variance outside the context of that manipulation. The critique of non-naturalistic experiments is not a recent development; it echoes a persistent and subversive thread in the history of modern psychology. The brain has evolved to guide behavior in a multidimensional world with many interacting variables. The assumption that artificially decoupling and manipulating these variables will lead to a good understanding of the brain may be untenable. Recent advances in artificial neural networks provide an alternative computational framework to model cognition in natural contexts. In contrast to the simplified and interpretable hypotheses we test in the lab, these models do not learn simple, human-interpretable rules or representations of the world. Instead, they use local computations to interpolate over task-relevant manifolds in high-dimensional parameter space. Counterintuitively, over-parameterized deep neural models are parsimonious and straightforward, as they provide a versatile, robust solution for learning a diverse set of functions in natural contexts. Naturalistic paradigms should not be deployed as an afterthought if we hope to build models of brain and behavior that extend beyond the laboratory into the real world. In my talk, I will discuss the relevance of deep neural models to cognition in the context of natural language and deep language models. Zoom link- https://weizmann.zoom.us/j/95406893197?pwd=REt5L1g3SmprMUhrK3dpUDJVeHlrZz09 Meeting ID: 954 0689 3197 Password: 750421