Survey of spiking in the mouse visual system reveals functional hierarchy

Abstract

The mammalian visual system, from retina to neocortex, has been extensively studied at both anatomical and functional levels. Anatomy indicates the cortico-thalamic system is hierarchical, but characterization of cellular-level functional interactions across multiple levels of this hierarchy is lacking, partially due to the challenge of simultaneously recording activity across numerous regions. Here, we describe a large, open dataset (part of the Allen Brain Observatory) that surveys spiking from units in six cortical and two thalamic regions responding to a battery of visual stimuli. Using spike cross-correlation analysis, we find that inter-area functional connectivity mirrors the anatomical hierarchy from the Allen Mouse Brain Connectivity Atlas. Classical functional measures of hierarchy, including visual response latency, receptive field size, phase-locking to a drifting grating stimulus, and autocorrelation timescale are all correlated with the anatomical hierarchy. Moreover, recordings during a visual task support the behavioral relevance of hierarchical processing. Overall, this dataset and the hierarchy we describe provide a foundation for understanding coding and dynamics in the mouse cortico-thalamic visual system..

Directly interfacing brain and deep networks exposes non-hierarchical visual processing

“…The deep learning revolution in neuroscience began when layers of DCNNs were related to regions along the ventral visual stream in an early-to-early and late-to-late pattern of correspondence between brain regions and model layers ( 3 – 5 ) (fig 1A). This correspondence supported the view that the ventral stream is a hierarchy in which ever more complex features and higher-level information are encoded as one moves from early visual areas like V1 or V4 to inferotemporal (IT) cortex ( 6 – 8 ).…”

Frontal circuit specialisations for decision making

“…The average resting time constant of each cortical area corresponds closely to its position in the anatomical hierarchy and the number of recurrent excitatory connections in that area (Chaudhuri et al, 2015). More recently, similar organising principles of resting time constants have also been found in the rodent (Siegle et al, 2021) and human brain (Demirtaş et al, 2019;Gao et al, 2020;Vidaurre et al, 2018). Several studies have also shown that neurons with longer resting time constants are more likely to be functionally involved in temporally extended cognitive tasks (Cavanagh et al, ,2016(Cavanagh et al, , , 2018Fascianelli et al, 2019;Nishida et al, 2014;Wasmuht et al, 2018).…”

Hierarchy in sensory processing reflected by innervation balance on cortical interneurons

“…To assess the significance of the hierarchy levels of cortical and thalamic areas, we generated 500 sampled connectivity data of the same size via bootstrapping and then computed the hierarchy scores of the cortical and thalamic areas using the bootstrapped connectivity data, following the method of Siegle et al ( 23 ). We found that in the hierarchy constructed from both CC and TC connections, only the hierarchy scores of thalamic areas SMT and AM/AD/AV/IAD are not significantly different ( P = 0.74, Wilcoxon signed-rank test).…”