Past events

Although animals are known to heavily rely on chemical signals for intraspecies communication, the matter of human chemical communication remains greatly contentious. I will present evidence supporting the claim that humans, just like other animals, rely on bodily-odors to effectively navigate the social world. First, I will present a quantification of people’s overt olfactory-sampling behavior. Of approximately 400 respondents, 94% acknowledged engaging in smelling their close relationships, and approximately 60% acknowledged sniffing strangers. Next, we tested if this olfactory information is employed for socially-relevant behavioral decisions, such as trust, a key element in human socialization. We found that subliminal exposure to body-odor increased implicit trustworthiness attributed to anthropomorphic non-humans. Finally, I will describe the effect of a specific body-volatile, Hexadecanal (HEX), on human impulsive aggression. Using validated behavioral paradigms, we observed a remarkable dissociation: sniffing HEX blocked aggression in men, but triggered aggression in women. Using functional brain imaging, we uncovered a pattern of brain activity mirroring behavior: In both men and women, HEX increased activity in an area implicated in the perception of social cues. Hex then modulated functional connectivity in a brain network implicated in aggressive behavior in a sex-dependent manner. Altogether, the thesis puts forward the hypothesis that chemosignals are a form of human social communication. Under this premise, human sampling behavior of self and others’ body-volatiles provides one with important information that, in turn, affects behaviors central to human society, such as trust and aggression. Zoom link to join: https://weizmann.zoom.us/j/98031517872?pwd=U0EvNG5EdGJBL24zWmpKUlY1akdnZz09 Meeting ID: 980 3151 7872 Password: 976632

During early life the neural code must develop to appropriately transform sensory inputs into behavioural outputs. However little is known about how developments in neural representations directly impact on behaviour. By combining behavioural analysis with 2-photon calcium imaging at multiple timepoints from 4 to 15 dpf in the optic tectum of developing zebrafish larvae, we demonstrate a link between the maturity of neural coding in the visual brain and developmental changes in visually-guided behavior. We show that visually-driven hunting behavior improves from 4 to 15 days post-fertilization, becoming faster and more accurate. During the same period population activity in parts of the optic tectum refines, improving decoding and information transmission for particular spatial positions. Together these results show that developmental signatures of an emerging neural code can be directly related to observable properties of behaviour. Please click the link below to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

The brain is rife with feedback connections within and between its regions, which almost inevitably should give rise to dynamic activity in the underlying neuronal populations. In the taste system of awake rats, neurons sequentially transition between activity states that correlate with taste perceptions such as identity, palatability, and novelty. In my talk I will present the current knowledge regarding taste information processing in the taste system and will add our recent description of sub-second novelty information transmission through a new circuit. Next, I will present unpublished data showing the dynamic changes in neuronal activity as taste memory is acquired and consolidated across 12 hours in behaving rats. Last, I will show how taste learning helps us investigating the early, pre-pathological, stages of Alzheimer’s disease. Zoom link to join: https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09 Meeting ID: 966 0803 3618 Password: 564068 Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

According to the hierarchical predictive-coding framework, regularities in the environment are used by the nervous system for predicting the input, and deviations from this prediction are transmitted as ‘prediction errors’. However, regularities may be based on more than one dimension and may be based on different time windows. Multiple predictions, sometimes contradicting, may be formed simultaneously and it is not clear how the brain deals with this situation. I will present evidence from scalp and intracranial EEG (in humans) showing that different parts of auditory cortex and frontal cortices are involved in predictions in multiple time scales for the same events. These predictions do not obey a simple hierarchy.