Spike Timing Neural Model of Motion Perception and Decision Making

Abstract

The paper presents a hierarchical spike timing neural network model developed in NEST simulator aimed to reproduce human decision making in simplified simulated visual navigation tasks. It includes multiple layers starting from retina photoreceptors and retinal ganglion cells (RGC) via thalamic relay including lateral geniculate nucleus (LGN), thalamic reticular nucleus (TRN), and interneurons (IN) mediating connections to the higher brain areas—visual cortex (V1), middle temporal (MT), and medial superior temporal (MTS) areas, involved in dorsal pathway processing of spatial and dynamic visual information. The last layer—lateral intraparietal cortex (LIP)—is responsible for decision making and organization of the subsequent motor response (saccade generation). We simulated two possible decision options having LIP layer with two sub-regions with mutual inhibitory connections whose increased firing rate corresponds to the perceptual decision about motor response—left or right saccade. Each stage of the model was tested by appropriately chosen stimuli corresponding to its selectivity to specific stimulus characteristics (orientation for V1, direction for MT, and expansion/contraction movement templates for MST, respectively). The overall model performance was tested with stimuli simulating optic flow patterns of forward self-motion on a linear trajectory to the left or to the right from straight ahead with a gaze in the direction of heading.

The interaction between elapsed time and decision accuracy differs between humans and rats

“…It remains unclear to us whether and how other classes of models (19,37,(42)(43)(44)(45)) might account for both species' data, but this is an interesting question for future research. It is hoped that exploring this question will lead to model refinements and help distinguish among alternative theories (46).…”

“…We therefore recruited a second cohort of 55 new subjects (Phase 2). In an effort to reduce inter-subject variability, the enrollment criteria specified a narrower age range (18)(19)(20)(21)(22)(23)(24)(25) and required that the subject was not currently taking any psychiatric medication, in addition to normal or corrected vision and hearing (by self-report). To improve motivation, compensation was linked to performance (number of correct responses, or "points" earned).…”

“…The accuracy and timing of sensory discriminations have been used to study mechanisms of decision-making for over a century (1). In particular, a visual random dot coherent motion task (2,3 ) has been extensively used to study decision-making in human and monkeys (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). In each trial, many small high-contrast dots are plotted at random locations in part of the visual field of a subject.…”

The Interaction Between Elapsed Time and Decision Accuracy Differs Between Humans and Rats

“…It remains unclear to us whether and how other classes of models (Wang, 2002; Wong et al, 2007; Beck et al, 2008; Latimer et al, 2015; Koprinkova-Hristova et al, 2019; Zoltowski et al, 2019) might account for both species’ data, but this is an interesting question for future research. It is hoped that exploring this question will lead to model refinements and help distinguish among alternative theories (Churchland and Kiani, 2016).…”

“…The accuracy and timing of sensory discriminations have been used to study mechanisms of decision-making for over a century (Heitz, 2014). In particular, a visual random dot coherent motion task (Britten et al, 1992, 1996) has been extensively used to study decision-making in human and monkeys (Newsome et al, 1989; Shadlen et al, 1996; Shadlen and Newsome, 2001; Mazurek et al, 2003; Huk and Shadlen, 2005; Palmer et al, 2005; Gold and Shadlen, 2007; Churchland et al, 2008; Kiani et al, 2008; Hanks et al, 2011; Bollimunta and Ditterich, 2012; Bollimunta et al, 2012; Purcell and Kiani, 2016; Yates et al, 2017; Shushruth et al, 2018; Alamia et al, 2019; Koprinkova-Hristova et al, 2019; Shooshtari et al, 2019; Olianezhad et al, 2019). In each trial, many small high-contrast dots are plotted at random locations in part of the visual field of a subject.…”