Biology subjects

McFadyen, J.

Publications and source records attributed to McFadyen, J..

5 recordsLinked to original sources

bioRxiv2025

Biased replay of aversive and uncertain outcomes underlies irrational decision making

Humans often make irrational decisions when facing uncertain or aversive future events despite careful deliberation. How we make choices, including irrational ones1,2, has been the object of extensive study both behaviourally and neurally3-6 and is the focus of influential behavioural economic theories7-9. Yet, little is known about how these (irrational) decisions are carved out in the brain. Here, using magnetoencephalography (MEG), we show that the construction and outcome evaluation of irrational decisions involves rapid, sequential state reactivation, or "replay."10. During deliberation, we show that forward replay is biased towards choice options with more negative and uncertain outcomes, with this bias further amplified immediately preceding irrational choice. Likewise, post-decision evaluation relates to replay in a choice-dependent manner. Following irrational choices, relief-like signals were evident as stronger backward replay of worse counterfactual options, while after rational decisions, regret-like signals appeared as stronger backward replay of better counterfactual options. Together, these findings suggest that neural replay shapes both the formation and reflection of irrational decisions, and poise replay as a candidate mechanism underlying pervasive decision biases in humans.

neuroscience↗

bioRxiv2021

Differential replay for reward and punishment paths predicts approach and avoidance

Planning is thought to involve neural replay, where states relevant to a task goal are rapidly reactivated in sequence. It remains unclear if, during planning, replay of a path relates to an actual prospective choice. Here, using magnetoencephalography (MEG), we studied participants while they planned to either approach or avoid an uncertain environment that contained paths leading to reward and to punishment. We show significant planning-related forward sequential replay with state-to-state transitions in the range of 20 to 90 ms. Replay of rewarding paths was boosted prior to a decision to avoid, and attenuated prior to a decision to approach. Crucially, a trial-by-trial bias in replaying punishing paths predicted an irrational choice to approach when a prospective environment was more risky, an effect that was particularly marked in more anxious participants. The findings reveal a coupling between the content of forwards replay and rational choice behaviour, such that replay prioritises an online representation of potential reward.

neuroscience↗

bioRxiv2021

Neural and computational processes of accelerated perceptual awareness and decisions: A 7T fMRI Study

Rapidly detecting salient information in our environments is critical for survival. Visual processing in subcortical areas like the pulvinar and amygdala have been shown to facilitate unconscious processing of salient stimuli. It is unknown, however, if and how these areas might interact with cortical networks to facilitate faster conscious perception of salient stimuli. Here we investigated these neural processes using 7T functional Magnetic Resonance Imaging (fMRI) in concert with computational modelling while participants (n = 32) engaged in a breaking continuous flash suppression paradigm (bCFS) in which fearful and neutral faces are initially suppressed from conscious perception but then eventually "breakthrough" into awareness. We found that participants reported faster breakthrough times for fearful faces compared to neutral faces. Drift-diffusion modelling suggested that perceptual evidence was accumulated at a faster rate for fearful faces compared to neutral faces. For both neutral and fearful faces, faster response times coincided with greater activity in the amygdala (specifically within its subregions, including superficial, basolateral and amygdalo-striatal transition area) and the insula. Faster rates of evidence accumulation coincided with greater activity in frontoparietal regions and the occipital lobe, as well as the amygdala. Overall, our findings suggest that hastened perceptual awareness of salient stimuli recruits the amygdala and, more specifically, is driven by accelerated evidence accumulation in fronto-parietal and visual areas. In sum, we have uncovered and mapped distinct neural computations that accelerate perceptual awareness of visually suppressed faces.

neuroscience↗

bioRxiv2019

Surprising threats accelerate evidence accumulation for conscious perception

Our survival depends on how well we can rapidly detect threats in our environment. To facilitate this, the brain is faster to bring threatening or rewarding visual stimuli into conscious awareness than neutral stimuli. Unexpected events may indicate a potential threat, and yet we tend to respond slower to unexpected than expected stimuli. It is unclear if or how these effects of emotion and expectation interact with ones conscious experience. To investigate this, we presented neutral and fearful faces with different probabilities of occurance in a breaking continuous flash suppression (bCFS) paradigm. Across two experiments, we discovered that fulfilled prior expectations hastened responses to neutral faces but had either no significant effect (Experiment 1) or the opposite effect (Experiment 2) on fearful faces. Drift diffusion modelling revealed that, while prior expectations accelerated stimulus encoding time (associated with the visual cortex), evidence was accumulated at an especially rapid rate for unexpected fearful faces (associated with activity in the right inferior frontal gyrus). Hence, these findings demonstrate a novel interaction between emotion and expectation during bCFS, driven by a unique influence of surprising fearful stimuli that expedites evidence accumulation in a fronto-occipital network.

neuroscience↗

bioRxiv2018

An afferent subcortical white matter pathway to the amygdala facilitates fear recognition

Our ability to rapidly detect threats is thought to be subserved by a subcortical pathway that quickly conveys visual information to the amygdala. This neural shortcut has been demonstrated in animals but has rarely been shown in the human brain. Importantly, it remains unclear whether such a pathway might influence neural activity and behaviour. We conducted a multimodal neuroimaging study of 622 participants from the Human Connectome Project. We applied probabilistic tractography to diffusion-weighted images, reconstructing a subcortical pathway to the amygdala from the superior colliculus via the pulvinar. We then computationally modelled the flow of neural activity during a face-viewing task and found strong evidence for a functionally-afferent subcortical pathway. Critically, individuals with greater fibre density in this pathway also had stronger dynamic coupling and enhanced fearful face recognition. Our findings provide converging evidence for the recruitment of an afferent subcortical route to the amygdala in the human brain that facilitates fear recognition.

neuroscience↗