Ventromedial prefrontal cortex subregion contributions to human safety estimation
Poster No:
758
Submission Type:
Abstract Submission
Authors:
Sarah Tashjian1, Joseph Cussen2, Wenning Deng3, Bo Zhang3, Dean Mobbs3
Institutions:
1University of Melbourne, Carlton, Victoria, 2University of Melbourne, Parkvilel, Victoria, 3California Institute of Technology, Pasadena, CA
First Author:
Co-Author(s):
Introduction:
Pivotal to self-preservation is the ability to identify when we are safe and when we are in danger. Previous studies have focused on safety estimations based on the features of external threats but do not consider how the brain integrates other key factors, including estimates about our ability to protect ourselves. Here we examine the neural systems underlying the online dynamic encoding of safety. We test two primary hypotheses regarding the functioning of safety neural circuitry: (1) that the neural systems involved in representing threat and protection are dissociable, and (2) that the brain integrates threat and protective information to confer a safety meta-representation. We hypothesize a candidate region for human safety coding is the ventromedial prefrontal cortex (vmPFC).
Methods:
In two preregistered samples using a novel Safety Estimation Task (N=100 behavioral; N=30 functional magnetic resonance imaging, fMRI; https://osf.io/hw3r9), we examined how subjects evaluated different types of safety information (Safety Prediction), as well as how they integrated information to estimate safety when perceptually identical stimuli changed in value (Safety Meta-representation). As a comparison, we examined neural activation when safety was certain during the outcome phase (Safety Recognition). We also tested how safety estimation changed as a function of experience (Safety Value Updating) in a separate task administered before and after the Safety Estimation Task. We examined safety coding at the whole-brain level but focused on the contributions of the vmPFC as a hypothesized safety coding hub. No prior study to our knowledge has systematically manipulated both threat and protection concerning safety judgments.
Results:
The vmPFC emerged as a robust hub of human safety coding during safety estimation, including Safety Prediction, Meta-representation, Recognition, and Value Updating, with specific tuning to protective information. Subjects were quicker to detect safety when presented with self-relevant protective stimuli compared to when presented with externally-relevant threat stimuli. Neurally, vmPFC activation parametrically increased as protection increased in safety value. Threat stimuli, in contrast, activated sensory and defensive neural systems. Despite equivalent experimentally established safety probabilities for threat and protection stimuli, only protection evoked activation in the vmPFC. Subjects meta-represented the first stimulus when evaluating the second stimulus, despite the absence of perceptual information about the first stimulus. Multivariate connectivity revealed a safety network consisting of the anterior and posterior vmPFC, dorsal and ventral striatum, ACC, and insula. Threat and protection networks showed a shift in hub organization from the posterior to anterior vmPFC.
·Behavioral results showed subjects reached the safety detection threshold faster when protection was presented first, showing biased predictions based on stimulus type.
·Overlapping neural response for each task phase, highlighting the role of the vmPFC in responding to safety increases.
Conclusions:
The vmPFC coded safety during all task states (Prediction, Meta-representation, Recognition, Value Updating). Activation was primarily identified in area 14m, with Safety Recognition and Value Updating extending to area 10. We identified a gradient from the posterior to the anterior part of vmPFC area 14m with activation extending more anterior as safety increased in certainty. This gradient supports the possibility of subparcellation of area 14m into smaller areas with posterior and anterior distinction, and aligns with the broader organizational gradient of the prefrontal cortex. The posterior vmPFC encoded simpler representations of threat whereas the anterior vmPFC encoded more complex safety associations. Results support our theoretical work identifying the anterior vmPFC as pivotal to integrating the value of self-relevant stimuli to influence the higher-order construction of affective processes, including safety (Tashjian et al., 2021 TICS). Our work is situated in a broader understanding that the vmPFC supports self-referential processing and identifies a role for the vmPFC in integrating threat into the broader narrative of the self.
Emotion, Motivation and Social Neuroscience:
Reward and Punishment 2
Emotion and Motivation Other
Higher Cognitive Functions:
Higher Cognitive Functions Other 1
Modeling and Analysis Methods:
fMRI Connectivity and Network Modeling
Novel Imaging Acquisition Methods:
BOLD fMRI
Keywords:
Affective Disorders
Cognition
Cortex
FUNCTIONAL MRI
Learning
Meta-Cognition
Multivariate
NORMAL HUMAN
Pre-registration
1|2Indicates the priority used for review