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Translaminar recurrence from layer 5 suppresses superficial cortical layers.
Koun Onodera1,2,3, Hiroyuki K Kato4,5,6
1Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Nature Communications
|May 13, 2022
Summary
Deep layer 5 (L5) feedback projections suppress superficial layer activity in the auditory cortex, sharpening feature selectivity. This inhibitory recurrence enhances sensory processing by refining spectro-temporal integration.
Area of Science:
- Neuroscience
- Auditory Cortex Research
- Sensory Processing
Background:
- Information flow in the sensory cortex is traditionally viewed as feedforward, with deep layers (L5) as output.
- Recurrent excitatory projections from L5 to superficial layers (L2/3) exist but their function is unclear.
Purpose of the Study:
- To investigate the functional impact of L5 feedback projections on sensory processing in the primary auditory cortex.
- To elucidate the circuitry and effects of L5 feedback on superficial layer activity.
Main Methods:
- Layer-selective optogenetic manipulations in the primary auditory cortex.
- Analysis of neuronal activity and response properties.
Main Results:
- L5 feedback inputs suppress superficial layer activity, irrespective of arousal level.
- This suppression is mediated by translaminar circuitry (intratelencephalic neurons) and subcortical projections (pyramidal tract neurons).
- L5 activation sharpens tone-evoked responses in superficial layers in both frequency and time domains.
Conclusions:
- Deep layer 5 feedback establishes a translaminar inhibitory recurrence.
- This inhibitory recurrence sharpens feature selectivity in superficial cortical layers.
- Findings reveal a novel mechanism for cortical spectro-temporal integration.
