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Updated: May 8, 2026
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Stimulating the Lip Motor Cortex with Transcranial Magnetic Stimulation
Published on: June 14, 2014
A circuit for motor cortical modulation of auditory cortical activity
Anders Nelson1, David M Schneider, Jun Takatoh
1Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Summary
The motor cortex sends signals to the auditory cortex, suppressing sound processing during movement. This neural circuit helps distinguish self-generated sounds from external stimuli.
Area of Science:
- Neuroscience
- Auditory system research
- Motor control mechanisms
Background:
- Normal hearing requires distinguishing self-generated sounds from external sounds.
- Neural circuits transmitting motor commands to the auditory system are crucial but poorly understood.
- Cortical interactions between motor and auditory areas are implicated in auditory comprehension and hallucinations.
Purpose of the Study:
- To characterize the circuitry transmitting motor-related signals to the auditory cortex in mice.
- To elucidate the synaptic organization and function of the motor-auditory cortex pathway.
Main Methods:
- Retrograde viral tracing to identify projections from the medial agranular motor cortex (M2) to the auditory cortex.
- In vitro and in vivo electrophysiology (whole-cell, intracellular), optogenetics, and pharmacology.
- Sound playback experiments to assess the functional impact of M2 activation on auditory cortical activity.
Main Results:
- Neurons in superficial and deep layers of M2 directly project to the auditory cortex.
- M2 axons form excitatory synapses but primarily suppress auditory cortical neuron activity via feedforward inhibition.
- Direct M2 activation suppresses spontaneous and evoked activity in auditory cortical neurons, dependent on timing.
Conclusions:
- A corticocortical circuit from M2 to the auditory cortex is identified, capable of transmitting motor-related signals.
- This circuit likely plays a role in movement-related suppression of auditory cortical activity.
- Understanding this pathway offers insights into auditory processing during movement and pathological states.
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