Whisker map organization in somatosensory cortex of awake, behaving mice

Abstract

The whisker map in rodent somatosensory cortex is well characterized under anesthesia, but its organization during awake sensation, when cortical coding can differ strongly, is unknown. Using a novel behavioral task, we measured whisker receptive fields and maps in awake mice with 2-photon calcium imaging in vivo. During a whisker-attentive task, layer 2/3 pyramidal neurons were sharply tuned, with cells tuned to different whiskers intermixed in each column. This salt-and-pepper organization consisted of small clusters of similarly-tuned neurons superimposed on a mean subcolumnar map. Parvalbumin interneurons had broader tuning, and were more homogeneously tuned to the columnar whisker. During a sound-attentive task, whisker tuning of pyramidal cells was less heterogeneous in each column, and firing correlations increased. Thus, behavioral demands modulate fine-scale map structure, and decorrelate the whisker map during whisker-attentive behavior.

VIP interneurons in mouse whisker S1 exhibit sensory and action-related signals during goal-directed behavior

“…This is shown in the rank-ordered receptive field for only the whisker-responsive cells which had their CW at the center of the piezo array (BW tuning preference = 0.48 ± 0.01), which was not significantly different from the remaining dataset (BW tuning preference = 0.51 ± 0.02; p = 0.085, Wilcoxon rank-sum test). Whisker tuning of VIP cells (BW tuning preference = 0.49 ± 0.01; see Figure S1C for CW centered tuning curves) was slightly broader than previously reported for PYR cells in awake mice 16 , consistent with VIP tuning for other sensory features in visual 17 and auditory cortex 18 .…”

“…41.8% of VIP cells in a given column were tuned the CW, 20.3% were tuned to neighboring whiskers in the same row, 11.5% in same arc, 14.9% at diagonal positions and 11.5% at further on the whisker pad (Figure 1O). The fraction of VIP cells with tuning that matches the CW is similar to that for PYR cells in awake mice 16 . This fraction (% CW/BW match) declined as function of distance from the column center (Figure 1P).…”

“…This average whisker response was greatest at the reference column center, and gradually fell off across the width of multiple barrel columns. Thus, VIP cells showed whisker tuning with average correct somatotopy in S1, but with an intermixed organization with very high local scatter, similar to PYR cells in mouse S1 16 . The above analysis of whisker tuning included both VIP cells driven only by whisker stimuli and those activated by both whisker stimuli and licks.…”

“…Thus, VIP cells were tuned to specific whiskers. In mouse barrel cortex, L2/3 pyramidal cells tuned to different whiskers are intermixed in each column in salt-andpepper organization [15][16] . We examined the tuning organization of VIP cells in the whisker map (Figure 1G).…”

The sensorimotor strategies and neuronal representations of tactile shape discrimination in mice

“…Indeed, neurons in thalamorecipient layer 4 typically respond best to stimulation of an anatomically corresponding whisker. However, outside of L4 the preference for any particular whisker is much weaker (Brecht et al, 2003;Clancy et al, 2015;Jacob et al, 2008;De Kock et al, 2007;Peron et al, 2015;Pluta et al, 2017;Ramirez et al, 2014), and indeed attending to whisker input decreases somatotopy (Wang et al, 2019).…”