Burst spiking encodes exploratory whisker touch

28 June 2021

Teams at the VU Amsterdam, Heidelberg University, Center of Advanced European Studies and Research (Bonn) and Max Planck Institute for Neurobiology (Martinsried) achieve next step in understanding how sensory information is represented across different cell-types of primary somatosensory (barrel) cortex of behaving rats. Their findings were published in Communications Biology.

Diversity of cell-types that collectively shape the cortical microcircuit ensures the necessary computational richness to orchestrate a wide variety of behaviors. The information content embedded in spiking activity of identified cell-types remain unclear to a large extent. Here, we recorded spike responses upon whisker touch of anatomically identified excitatory cell-types in primary somatosensory cortex in naive, untrained rats. We find major differences across layers and cell-types. The temporal structure of spontaneous spiking contains high-frequency bursts (≥100 Hz) in all morphological cell-types but a significant increase upon whisker touch is restricted to layer L5 thick-tufted pyramids (L5tts) and thus provides a distinct neurophysiological signature. We find that whisker touch can also be decoded from L5tt bursting, but not from other cell-types. We observed high-frequency bursts in L5tts projecting to different subcortical regions, including thalamus, midbrain and brainstem. We conclude that bursts in L5tts allow accurate coding and decoding of exploratory whisker touch.

Left panel: Example trace of Layer 5 thick tufted neuron with sliding window to obtain spiking characteristics and associated behavior. High-frequency bursts are highlighted in red, accompanied by red asterisks.
Middle panel: decoding performance was calculated as the area under the receiver operating characteristic curve (AUROC curve) and figure panel illustrates AUROC values as a function of cell type.
Right panel: Cumulative distribution of absolute AUROC value as a function of cell-type (Kolmogorov–Smirnov test for comparison of two distributions, L5tt vs rest, p < 0.01).

From: deKock et al, CommsBiol 2021
doi: 10.1038/s42003-021-02241-8