The Bayesian brain and cooperative communication in schizophrenia

Abstract

The act of will and the action of the body are not two different states…; they do not stand in the relation of cause and effect but are one and the same thing…. The action of the body is nothing but the act of will …. translated into perception. -Arthur Schopenhauer, 1819 1 Our social world is an ever-changing milieu in which boundless verbal and nonverbal signals are generated by fellow humans. To ensure our survival, we must perceive certain regularities from the complexity that surrounds us. A failure to meet this daily challenge may prove costly for some; social encounters trigger several psychiatric symptoms, while social withdrawal reduces their intensity, at least temporarily. 2 For example, disorganization (or formal thought disorder), one of the central features of schizophrenia, presents primarily as a disruption in cooperative communication that occurs in a social context. Though many technical advances now allow us to study "socially" interacting agents in the laboratory (for example, see Kingsbury and colleagues 3 ), psychiatric symptoms are rarely studied in the context of neural mechanisms of social encounters. To tackle this challenge, we need empirical tools to study the dynamic neural framework of social interaction, starting from a 2-person perspective. In this editorial, we first present such a tool: an emerging "active inference" perspective of cooperative communication between 2 individuals. We then introduce the 2-brain problem of formal thought disorder in schizophrenia as an exemplar case of its utility and map resulting theoretical expectations to known signs of this construct. Lastly, we highlight several experimental opportunities that arise from casting of formal thought disorder in the active inference framework.

Clinical and Computational Speech Measures are Associated with Social Cognition in Schizophrenia Spectrum Disorders

“…Overall, the results support our initial hypotheses and are consistent with the active inference model of discourse which posits that accurate updating of priors based on internal and external (including social) cues is required for receptive and productive language (Brown and Kuperberg, 2015; Palaniyappan and Venkatasubramanian, 2022). Emotion processing (or alternatively, simulation) and mentalization could therefore be considered crucial components of linguistic functioning.…”

“…Both are linked to canonical SSD neural pathways and brain systems (Green et al, 2015; Kircher et al, 2018); clinically, both are related to poor outcomes and decreased functioning (Bowie et al, 2011; Couture et al, 2006; Schmidt et al, 2011; Tan et al, 2014). Several have suggested that social cognitive impairments and speech disturbances may share these characteristics not by coincidence - but rather, they are causally related to one another and to the pathogenesis of psychosis in general (Palaniyappan and Venkatasubramanian, 2022; Wible, 2012).…”

“…The Bayesian active inference model of discourse can be interpreted to imply a direct link between social cognition and speech (Brown and Kuperberg, 2015; Palaniyappan and Venkatasubramanian, 2022; Vasil et al, 2020). Simplistically, this model describes an active feedback process where the speaker monitors internal and, critically, external signals during speech production.…”

Language Network Dysfunction and Formal Thought Disorder in schizophrenia

“…Secondly, a computational linguistic readout may mathematically formalize the aberrant language behavior in FTD, but it does not in itself clarify the physiological steps needed to produce it, or the ways in which the LN realizes these steps. A generative model of how brain activity results in FTD is required to fill this gap (see [120,121]). Third, when using NLP approaches in psychosis, FTD is a latent (or hidden) psychopathological construct that we purport to measure using quantifiable linguistic readouts; the relationship between the parameters of the latent construct and the observational data needs rigorous model based testing, ideally in terms of comparing the evidence for competing models.…”

Language Network Dysfunction and Formal Thought Disorder in Schizophrenia

“…Secondly, a computational linguistic readout may mathematically formalise the aberrant language behavior in FTD, but it does not in itself clarify the physiological steps needed to produce it, or the ways in which the LN realizes these steps. A generative model of how brain activity results in FTD is required to fill this gap (see [121,122]). Third, when using NLP approaches in psychosis, FTD is a latent (or hidden) psychopathological construct that we purport to measure using quantifiable linguistic readouts; the relationship between the parameters of the latent construct and the observational data needs rigorous model based testing, ideally in terms of comparing the evidence for competing models.…”