Fronto-parietal Cortical Circuits Encode Accumulated Evidence with a Diversity of Timescales

Abstract

Decision-making in dynamic environments often involves accumulation of evidence, in which new information is used to update beliefs and select future actions. Using in vivo cellular resolution imaging in voluntarily head-restrained rats, we examined the responses of neurons in frontal and parietal cortices during a pulse-based accumulation of evidence task. Neurons exhibited activity that predicted the animal's upcoming choice, previous choice, and graded responses that reflected the strength of the accumulated evidence. The pulsatile nature of the stimuli enabled characterization of the responses of neurons to a single quantum (pulse) of evidence. Across the population, individual neurons displayed extensive heterogeneity in the dynamics of responses to pulses. The diversity of responses was sufficiently rich to form a temporal basis for accumulated evidence estimated from a latent variable model. These results suggest that heterogeneous, often transient sensory responses distributed across the fronto-parietal cortex may support working memory on behavioral timescales. VIDEO ABSTRACT.

Neural Correlates of Cognition in Primary Visual versus Neighboring Posterior Cortices during Visual Evidence-Accumulation-based Navigation

“…5 H). Our results are also compatible with other experimental observations of increasing timescales along a cortical hierarchy (Murray et al 2014;Runyan et al 2017;Dotson et al 2018;Schmolesky et al 1998) , and furthermore show that even regions as early as V1 contain across-trial information about choice, reward, and sensory history, as previously reported in frontoparietal areas (Morcos and Harvey 2016;Scott et al 2017;Akrami et al 2018) . A gradual increase in timescales across brain areas suggest that each area may contribute incrementally to the persistence of information, and if so, our data support that this process also includes the visual cortices.…”

“…In trials with sparse occurrences of preferred-side cues, the activities of these cells tended to return to baseline following a fairly stereotyped impulse response. Individually they thus seemed to code only information about momentary cues, although as a population they can form a more persistent stimulus memory (Goldman 2009;Scott et al 2017;Miri et al 2011) . Interestingly, the amplitudes of these cells' responses seemed to be variable in a structured way, both across time in a trial, as well as across trials where the mouse made right vs. left choices (columns in Fig.…”

The complexity dividend: when sophisticated inference matters

“…Adaptivity is achieved in our models using a bank of different integration timescales, consistent with multiple reports describing different integration timescales in the brain (Gläscher & Büchel, 2005;Hasson et al, 2008;Bromberg-Martin et al, 2010;Bernacchia et al, 2011;Bornstein & Daw, 2012;Honey et al, 2012;Hasson et al, 2015;Meder et al, 2017;Scott et al, 2017;Runyan et al, 2017). In our formulation, the estimates obtained from these different integration timescales are weighted optimally and combined to produce a single output (Wilson et al, 2013(Wilson et al, , 2018.…”

Choice History Biases Subsequent Evidence Accumulation

“…Relatedly, neurophysiological work on ongoing activity has inferred multiple, hierarchically organized, timescales in different cortical regions (Honey et al, 2012;Murray et al, 2014;Chaudhuri et al, 2015;Runyan et al, 2017;Scott et al, 2017). The history-dependent evidence accumulation biases we have uncovered here might index the interplay between these different effective timescales with long-timescale accumulators at higher stages biasing short-timescale accumulators at intermediate stages of the cortical hierarchy.…”

“…Neural signals reflecting previous choices have been found across the sensorimotor pathways of the cerebral cortex, from sensory to associative and motor regions (Gold et al, 2008;de Lange et al, 2013;Akaishi et al, 2014;Pape and Siegel, 2016;Purcell and Kiani, 2016a;St. John-Saaltink et al, 2016;Thura et al, 2016;Hwang et al, 2017;Scott et al, 2017).…”