Midbrain local circuits shape sound intensity codes.


Midbrain local circuits shape sound intensity codes.


Grimsley Calum Alex; Sanchez Jason Tait; Sivaramakrishnan Shobhana


Frontiers in neural circuits




Hierarchical processing of sensory information requires interaction at multiple levels along the peripheral to central pathway. Recent evidence suggests that interaction between driving and modulating components can shape both top down and bottom up processing of sensory information. Here we show that a component inherited from extrinsic sources combines with local components to code sound intensity. By applying high concentrations of divalent cations to neurons in the nucleus of the inferior colliculus in the auditory midbrain, we show that as sound intensity increases, the source of synaptic efficacy changes from inherited inputs to local circuits. In neurons with a wide dynamic range response to intensity, inherited inputs increase firing rates at low sound intensities but saturate at mid-to-high intensities. Local circuits activate at high sound intensities and widen dynamic range by continuously increasing their output gain with intensity. Inherited inputs are necessary and sufficient to evoke tuned responses, however local circuits change peak output. Push-pull driving inhibition and excitation create net excitatory drive to intensity-variant neurons and tune neurons to intensity. Our results reveal that dynamic range and tuning re-emerge in the auditory midbrain through local circuits that are themselves variable or tuned.


inferior colliculus; Animals; Mice; Neurons/physiology; Acoustic Stimulation; Auditory Perception/*physiology; Inferior Colliculi/*physiology; Auditory Pathways/*physiology; Auditory Threshold/physiology; high divalents; local circuits; monosynaptic; Neural Inhibition/*physiology; sound intensity


Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).






Grimsley Calum Alex; Sanchez Jason Tait; Sivaramakrishnan Shobhana, “Midbrain local circuits shape sound intensity codes.,” NEOMED Bibliography Database, accessed April 12, 2024, https://neomed.omeka.net/items/show/5136.