Biology subjects

Barnby, J. M.

Publications and source records attributed to Barnby, J. M..

4 recordsLinked to original sources

bioRxiv2026

Corpus Callosum Dysgenesis impairs metacognition: evidence from multi-modality and multi-cohort replications

The corpus callosum is the largest commissure in the mammalian brain and plays a major role in supporting cognitive processes required for adapting to complex environments. Individuals born with Corpus Callosum Dysgenesis (CCD), characterized by malformations of the corpus callosum, commonly exhibit deficits in social navigation, abstract problem-solving, decision-making, and self-awareness. Metacognition is a key cognitive process that supports these functions; however, it has yet to be tested comprehensively in individuals with CCD. Over three experiments, and three CCD cohorts, we tested the impact of this neurodevelopmental disorder on perceptual accuracy, confidence judgements, and metacognitive efficiency using two variants of a Random Dot Kinematogram task within lab, online, and VR conditions. We found that individuals with CCD typically displayed normal perceptual accuracy but failed to adjust their confidence judgements in line with task difficulty. Computational modelling revealed that this difference was explained by lower metacognitive efficiency driven by consistently lower metacognitive sensitivity. Together, these results provide evidence that the corpus callosum plays a crucial role in supporting metacognition.

neuroscience↗

bioRxiv2023

The role of serotonin and of perceived social differences in infering the motivation of others

Attributing motives to others is a crucial aspect of mentalizing, can be biased by prejudice, and also is affected by common psychiatric disorders. It is therefore important to understand in depth the mechanisms underpinning it. Toward improving models of mentalizing motives, we hypothesized that people quickly infer whether others motives are likely beneficial or detrimental, then refine their judgment ( Classify-refine). To test this, we used a modified Dictator game, a game theoretic task, where participants judged the likelihood of intent to harm vs. self-interest in economic decisions. Toward testing the role of serotonin in judgments of intent to harm, we delivered the task in a week-long, placebo vs. Citalopram study. Computational model comparison provided clear evidence for the superiority of Classify-refine models over traditional ones, strongly supporting the central hypothesis. Further, while Citalopram helped refine attributions about motives through learning, it did not induce more positive initial inferences about others motives. Finally, model comparison indicated a minimal role for racial bias within economic decisions for the large majority of our sample. Overall, these results support a proposal that classify-refine social cognition is adaptive, although relevant mechanisms of Serotonergic antidepressant action will need to be studied over longer time spans.

neuroscience↗

bioRxiv2023

D2/D3 dopamine supports the precision of mental state inferences and self-relevance of joint social outcomes

Striatal dopamine is important in paranoid attributions, although its computational role in social inference remains elusive. We employed a simple game theoretic paradigm and computational model of intentional attributions to investigate the effects of dopamine D2/D3 antagonism on ongoing mental state inference following social outcomes. Haloperidol, compared to placebo, enhanced the impact of partner behaviour on beliefs about the harmful intent of partners, and increased learning from recent encounters. These alterations caused significant changes to model covariation and negative correlations between self-interest and harmful intent attributions. Our findings suggest haloperidol improves belief flexibility about others and simultaneously reduces the self-relevance of social observations. Our results may reflect the role of D2/D3 dopamine in supporting self-relevant mentalisation. Our data and model bridge theory between general and social accounts of value representation. We demonstrate initial evidence for the sensitivity of our model and short social paradigm to drug intervention and clinical dimensions, allowing distinctions between mechanisms that operate across traits and states. Data AvailabilityAll data and code are available online: https://github.com/josephmbarnby/Barnby_etal_2023_D2D3Modelling Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=152 SRC="FIGDIR/small/539031v6_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@8bd39borg.highwire.dtl.DTLVardef@1f18845org.highwire.dtl.DTLVardef@2986b4org.highwire.dtl.DTLVardef@4abd90_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2019

Dopamine modulates paranoid social inferences: a double-blind, within-subject, randomised control study in a healthy population.

Altered dopamine transmission is thought to influence the formation of persecutory delusions. However, despite extensive evidence from clinical studies there is little experimental evidence on how modulating the dopamine system changes social attributions related to paranoia, and the salience of beliefs more generally. 27 healthy male participants received 150mg L-DOPA, 3mg haloperidol, or placebo in a double blind, randomised, placebo-controlled study, over three within-subject sessions. Participants completed a multi-round Dictator Game modified to measure social attributions, and a measure of belief salience spanning themes of politics, religion, science, morality, and the paranormal. We preregistered predictions that altering dopamine function would affect i) attributions of harmful intent and ii) salience of paranormal beliefs. As predicted, haloperidol reduced attributions of harmful intent across all conditions compared to placebo. L-DOPA reduced attributions of harmful intent in fair conditions compared to placebo. Unexpectedly, haloperidol increased attributions of self-interest for opponents decisions. There was no change in belief salience within any theme. These results could not be explained by scepticism or subjective mood. Our findings demonstrate the selective involvement of dopamine in social inferences related to paranoia in healthy individuals.

neuroscience↗