Mount Sinai Projects
Gu / Schiller labs
Nicotine-Related Beliefs Induce Dose-Dependent Responses in the Human Brain (Gu lab)
Beliefs have a powerful influence on our behavior, yet their neural mechanisms remain elusive. Here we investigate whether beliefs could impact brain activities in a way akin to pharmacological dose-dependent effects. Nicotine-dependent humans were told that nicotine strength in an electronic cigarette was either ‘low’, ‘medium’ or ‘high’, while nicotine content was held constant. After vaping, participants underwent functional neuroimaging and performed a decision-making task known to engage neural circuits affected by nicotine. Beliefs about nicotine strength induced dose-dependent responses in the thalamus, a key binding site for nicotine, but not in other brain regions such as the striatum. Nicotine-related beliefs also parametrically modulated the connectivity between the thalamus and ventromedial prefrontal cortex, a region important for decision-making. These findings reveal a high level of precision in the way beliefs influence the brain, offering mechanistic insights into humans’ heterogeneous responses to drugs and a pivotal role of beliefs in addiction.
Neural patterns dissociate traumatic from sad autobiographical memories in PTSD (Schiller lab)
For people with post-traumatic stress disorder (PTSD), recall of traumatic memories often displays as intrusions that differ profoundly from processing of ‘regular’ negative memories. These mnemonic features fueled theories speculating a unique cognitive state linked with traumatic memories. Yet, to date, little empirical evidence supports this view. Here we examined neural activity of patients with PTSD who were listening to narratives depicting their own memories. An intersubject representational similarity analysis of cross-subject semantic content and neural patterns revealed a differentiation in hippocampal representation by narrative type: semantically similar, sad autobiographical memories elicited similar neural representations across participants. By contrast, within the same individuals, semantically similar trauma memories were not represented similarly. Furthermore, we were able to decode memory type from hippocampal multivoxel patterns. Finally, individual symptom severity modulated semantic representation of the traumatic narratives in the posterior cingulate cortex. Taken together, these findings suggest that traumatic memories are an alternative cognitive entity that deviates from memory per se.
Intracranial signatures of Social Norm Encoding (Gu Lab)
Social norms and their enforcement are fundamental for society. The ability to dynamically detect and adapt to deviations from norms is central to individuals' normal social functioning.
We capitalize on microelectrode recordings during deep brain stimulation surgeries to study neuronal activity during social decision making conjointly with neuroeconomics-inspired behavioral modeling.
Computation of threat in
the human amygdala (Schiller lab)
When facing danger, an organism is tasked with learning the precursors of threat. The amygdala is a brain region central for the encoding of threat across species. However, which threat information is encoded at the single-neuron level in the human brain is unclear. To begin and answer this question, we capitalize on an single-unit recordings from surgical patients undergoing intracranial EEG.