Intracortical Inputs to Neurons in Layer 4 of Primary Auditory Cortex

Intracortical Inputs to Neurons in Layer 4 of Primary Auditory Cortex Public Deposited

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Kratz, Megan
- Affiliation: School of Medicine, UNC Neuroscience Center, Neuroscience Curriculum

Abstract

Primary auditory cortex (A1) is organized tonotopically. However, individual neurons in A1 respond to a wider range of sound frequencies than would be predicted by their thalamic inputs, which suggests the existence of cross-frequency intracortical inputs. We use photostimulation in slices of mouse A1 that contain the entire tonotopic map to identify cross-frequency intracortical inputs to Layer 4 (L4) neurons. We find that L4 neurons receive intracortical inputs from L4 and L6 neurons in columns ~300 μm caudal and/or rostral to the cell, in addition to local columnar input. These lateral inputs are most likely tuned to different frequencies than the neuron that receives them. This result suggests that L4 neurons receive inputs that have a harmonic relationship to their best frequencies. These lateral connections may be part of a circuit that allows A1 to detect auditory objects with specific harmonic structure.

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