Rat Prefrontal Cortex Inactivations during Decision Making Are Explained by Bistable Attractor Dynamics

Abstract

Two-node attractor networks are flexible models for neural activity during decision making. Depending on the network configuration, these networks can model distinct aspects of decisions including evidence integration, evidence categorization, and decision memory. Here, we use attractor networks to model recent causal perturbations of the frontal orienting fields (FOF) in rat cortex during a perceptual decision-making task (Erlich, Brunton, Duan, Hanks, & Brody, 2015 ). We focus on a striking feature of the perturbation results. Pharmacological silencing of the FOF resulted in a stimulus-independent bias. We fit several models to test whether integration, categorization, or decision memory could account for this bias and found that only the memory configuration successfully accounts for it. This memory model naturally accounts for optogenetic perturbations of FOF in the same task and correctly predicts a memory-duration-dependent deficit caused by silencing FOF in a different task. Our results provide mechanistic support for a "postcategorization" memory role of the FOF in upcoming choices.

A cortico-collicular pathway for motor planning in a memory-dependent perceptual decision task

“…2). These data support a role of the M2-SC pathway in maintaining choice memory 46 . Consistent with this interpretation, comparing perturbation effects in task trials with short versus long delays revealed stronger impairment as delay duration increased ( Fig.…”

Error-correcting dynamics in visual working memory

“…Previous work has emphasized the impact of noise on working memory, arguing this causes a memory to diffuse away from its original state (1,23,24). Our results suggest that underlying attractor dynamics have a significant influence on working memory representations.…”

“…Attractor dynamics are thought to reduce the impact of neural noise in long-term memory (20,21) and decision making (22,23) and have been hypothesized to play a similar role in working memory (24)(25)(26). Indeed, our results show attractor dynamics within mnemonic space limit the impact of random diffusion, reducing errors in working memory.…”

Lapses in perceptual decisions reflect exploration

“…However, considerable controversy remains as to which computations were affected by those disruptions. The effects were largely interpreted in terms of traditional ideal observer models, and thus attributed to perceptual biases (Guo et al, 2018), leaky accumulation (Erlich et al, 2015) or post categorization biases (Piet et al, 2017; Erlich et al, 2015). However, the asymmetric effects on lapses seen in these studies resembled the effects of the reward manipulations in our task, hinting that they may actually arise from action value changes.…”