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Updated: Dec 29, 2025
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Stereotactically-guided Ablation of the Rat Auditory Cortex, and Localization of the Lesion in the Brain
Published on: October 11, 2017
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Auditory cortex shapes sound responses in the inferior colliculus
Jennifer M Blackwell1,2, Alexandria Mh Lesicko1, Winnie Rao1
1Department of Otorhinolaryngology, University of Pennsylvania, Philadelphia, United States.
Elife
|February 1, 2020
Summary
Activating auditory cortex (AC) excitatory feedback to the inferior colliculus (IC) increases IC spontaneous activity and reduces sound selectivity. Inhibiting AC neurons or feedback projections did not alter IC responses, revealing excitatory feedback
Area of Science:
- Neuroscience
- Auditory Neuroscience
- Systems Neuroscience
Background:
- The auditory cortex (AC) extensively projects to the inferior colliculus (IC), influencing auditory processing.
- Previous methods for studying AC-IC interactions lacked cell-type specificity.
Purpose of the Study:
- To investigate the causal role of cortico-collicular feedback projections in modulating IC sound responses using optogenetics.
- To determine if specific AC inhibitory interneuron subtypes (PV, SST) control IC activity via feedback.
Main Methods:
- Optogenetic activation and suppression of cortico-collicular feedback projections in mice.
- Optogenetic modulation of parvalbumin-positive (PV) and somatostatin-positive (SST) inhibitory interneurons in the AC.
- Electrophysiological recording of IC neuronal responses to sound stimuli.
Main Results:
- Activation of excitatory cortico-collicular feedback increased IC spontaneous firing rates.
- Feedback activation decreased the stimulus selectivity of IC neurons.
- Suppression of feedback projections or modulation of AC PV/SST interneurons had no significant effect on IC sound responses.
Conclusions:
- Excitatory feedback from the auditory cortex directly influences IC spontaneous activity and stimulus encoding.
- Cortico-collicular feedback impacts auditory processing, but inhibition-driven AC activity does not appear to modulate IC sound responses through these pathways.
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