4 December 2024: Using computational modelling to explore excitatory and inhibitory function in cortical circuits in schizophrenia

Rick Adams
Centre for Medical Image Computing and Institute for Cognitive Neuroscience
University College London

The hypothesis that excitatory and inhibitory functioning in neural circuits is ‘imbalanced’ in schizophrenia (and psychosis spectrum disorders) is well known, but the details of this imbalance are unclear. I have used dynamic causal modelling of M/EEG data from people with schizophrenia diagnoses to estimate excitatory and inhibitory cell function in vivo. This work implies that a lack of pyramidal cell excitability is a core dysfunction in the disorder, but also that psychosis symptoms may be due – conversely – to disinhibition. Symptoms may therefore be the price the brain pays to restore function in imbalanced circuits.

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20 November 2024: No man is an island? Exploring impairments in semantic cognition and communication as pathways toward interpersonal computational psychiatry

Isaac Fradkin
Department of Psychology
The Hebrew University of Jerusalem

Comprehensible communication is critical for social functioning and well-being. In psychopathology, incoherent discourse is classically associated with psychotic disorders, where social difficulties are also prevalent. Yet, understanding the mechanisms driving incoherent discourse, and those linking it to social difficulties is particularly challenging for two main reasons. First, people do not express everything that comes to mind, rendering inferences from observed discourse to underlying mechanisms a challenge. Second, real-life communication involves complex interpersonal dynamics, and thus cannot be satisfactorily studied in classic single-person experiments. I will present a novel approach for studying the interplay between latent intrapersonal mechanisms and interpersonal dynamics in communication, using a simple word association task. First, I will present data from a recent transdiagnostic study, showing a specific relationship between alterations in discourse and socially contextualized psychiatric dimensions. Computational modeling of associative thinking in this sample has further demonstrated a differential involvement of semantic and executive impairments in different psychiatric dimensions. Then, I will show preliminary data from a multiplayer free association task, demonstrating how associative output and associative thinking can affect interpersonal impressions, and how people normally adapt to social contexts and social feedback. Together, these results highlight the importance and feasibility of studying computational mechanisms in psychiatry within interactive social contexts.     

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