Amplitude modulations of cortical sensory responses in pulsatile evidence accumulation

Abstract

How does the brain internally represent a sequence of sensory information that jointly drives a decision-making behavior? Studies of perceptual decision-making have often assumed that sensory cortices provide noisy but otherwise veridical sensory inputs to downstream processes that accumulate and drive decisions. However, sensory processing in even the earliest sensory cortices can be systematically modified by various external and internal contexts. We recorded from neuronal populations across posterior cortex as mice performed a navigational decision-making task based on accumulating randomly timed pulses of visual evidence. Even in V1, only a small fraction of active neurons had sensory-like responses time-locked to each pulse. Here we focus on how these 'cue-locked' neurons exhibited a variety of amplitude modulations from sensory to cognitive, notably by choice and accumulated evidence. These task-related modulations affected a large fraction of cue-locked neurons across posterior cortex, suggesting that future models of behavior should account for such influences.

Multiple timescales of sensory-evidence accumulation across the dorsal cortex

“…The towers were visible for 200 ms, and appeared at different positions in each trial, obeying spatial Poisson processes of different underlying rates on the rewarded and non-rewarded side. Compatible with our previous reports (Koay et al, 2020;Pinto et al, 2018Pinto et al, , 2019 , task performance was modulated by the difference in tower counts between the right and left sides (Fig. 1C, n = 20).…”

“…Decisions under uncertainty can be potentially solved in the brain through a chain of largely feedforward computations progressing from stimulus processing to accumulation of evidence to post-accumulation categorization and decision, with different brain areas implementing different steps of the process (Brincat et al, 2018;Brody and Hanks, 2016;Erlich et al, 2015;Gold and Shadlen, 2007;Hanks et al, 2015;Yartsev et al, 2018) . On the other hand, neural correlates of decisions relying on evidence accumulation have been found in a number of cortical and subcortical structures, in both primates and rodents (Ding and Gold, 2010;Hanks et al, 2015;Horwitz and Newsome, 1999;Kim and Shadlen, 1999;Koay et al, 2020;Krueger et al, 2017;Murphy et al, 2020;Orsolic et al, 2019;Scott et al, 2017;Shadlen and Newsome, 2001;Wilming et al, 2020;Yartsev et al, 2018) . Likewise, we have previously shown that, when mice must accumulate evidence over several seconds to make a navigational decision, the inactivation of widespread dorsal cortical areas leads to behavioral deficits, and that these areas encode multiple behavioral variables, including evidence (Pinto et al, 2019) .…”

“…A commonly studied type of time-extended decision making happens under perceptual uncertainty, which requires the gradual accrual of sensory evidence (Bogacz et al, 2006;Brody and Hanks, 2016;Brunton et al, 2013;Carandini and Churchland, 2013;Gold and Shadlen, 2007;Morcos and Harvey, 2016;Newsome et al, 1989;Odoemene et al, 2018;Stine et al, 2020;Sun and Landy, 2016;Tsetsos et al, 2012;Waskom and Kiani, 2018) . Neural correlates of decisions relying on evidence accumulation have been found in a number of cortical and subcortical structures, in both primates and rodents ( Brincat et al, 2018;Ding and Gold, 2010;Erlich et al, 2015;Hanks et al, 2015;Horwitz and Newsome, 1999;Kim and Shadlen, 1999;Koay et al, 2020;Krueger et al, 2017;Murphy et al, 2020;Orsolic et al, 2021;Scott et al, 2017;Shadlen and Newsome, 2001;Wilming et al, 2020;Yartsev et al, 2018) . Likewise, we have previously shown that, when mice must accumulate evidence over several seconds to make a navigational decision, the inactivation of widespread dorsal cortical areas leads to behavioral deficits, and that these areas encode multiple behavioral variables, including evidence (Pinto et al, 2019) .…”

A compact spatial map in V2 visual cortex

“…Although there is a lack of direct intrinsic projections between V2 and hippocampus, spatial and directional representations of V2 might be influenced by the hippocampal spatial information through indirect cortico-cortical connections such as the RSC, which is known to encode cortical spatial and directional signals (Mao et al, 2017; Mao et al, 2018; van Strien et al, 2009). Development of large-scale multi-site in vivo electrophysiological recording techniques may prove crucial to provide a complete picture of sensory coding of visual systems (Buzsaki et al, 2015; Koay et al, 2020; Siegle et al, 2021). Converging evidence has shown that higher-order visual areas such as V2 may encode additional non-visual cognitive cues including the location, direction and motion.…”

Distributed context-dependent choice information in mouse posterior cortex

“…Furthermore, the distribution of movement, perceptual, and decision variables over cortical space is not constrained by area boundaries (e.g., retinotopically defined), thus challenging a precise localization of these signals 21,27 . Task demands, such as the need to accumulate sensory evidence [28][29][30][31][32][33][34][35][36][37] or to engage shortterm memory mechanisms 20,25,28,[38][39][40][41][42][43][44][45][46][47][48] , and the targeted sensory modality 20,32,37,49 , all profoundly affect the strength and multi-network distribution of choice signals (reviewed in Supplementary Table 1). These complex dependences have been demonstrated in a series of inactivation studies that have profoundly changed our view of posterior parietal networks in decision computations.…”