Multi-finger receptive field properties in primary somatosensory cortex: A revised account of the spatiotemporal integration functions of area 3b

• Published in: Cell reports (Cambridge) Vol. 42; no. 3; p. 112176
• Main Authors: Trzcinski, Natalie K., Hsiao, Steven S., Connor, Charles E., Gomez-Ramirez, Manuel
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 28-03-2023; Elsevier
• Subjects: area 3b; Brain Mapping; CP: Neuroscience; cross-finger; Fingers; Hand; haptics; integration; monkey; multi-digit; multi-finger; non-human primate; orientation; receptive field; somatosensory; Somatosensory Cortex; Touch; area 3b; orientation; monkey; CP: Neuroscience; somatosensory; receptive field; haptics; non-human primate; RF; integration; multi-finger; multi-digit; cross-finger
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2023.112176

The leading view in the somatosensory system indicates that area 3b serves as a cortical relay site that primarily encodes (cutaneous) tactile features limited to individual digits. Our recent work argues against this model by showing that area 3b cells can integrate both cutaneous and proprioceptive information from the hand. Here, we further test the validity of this model by studying multi-digit (MD) integration properties in area 3b. In contrast to the prevailing view, we show that most cells in area 3b have a receptive field (RF) that extends to multiple digits, with the size of the RF (i.e., the number of responsive digits) increasing across time. Further, we show that MD cells’ orientation angle preference is highly correlated across digits. Taken together, these data show that area 3b plays a larger role in generating neural representations of tactile objects, as opposed to just being a “feature detector” relay site.
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•Area 3b cells have receptive fields that span multiple fingers•Response latency is faster in cells with a multi- vs. single-finger receptive field•Area 3b cells’ receptive field size increases as a function of time•Area 3b cells’ orientation preference is systematically phase-shifted across fingers
Trzcinski et al. show that area 3b cells have receptive fields (RFs) that span multiple fingers, a finding that runs counter to the leading RF model in somatosensory neocortex. The emergence of multi-fingers RFs is driven by feedback mechanisms, with cells’ cross-finger orientation preference phase-shifted to optimally encode curved objects.