Mixed Representations of Sound and Action in the Auditory Midbrain

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Computational Neuroscience

Background:

• Linking sensory input to behavioral consequences is crucial for brain function.
• Neocortical and limbic systems exhibit "mixed representations" integrating sensory and task variables.
• The extent of such integration in subcortical auditory pathways remains unclear.

Purpose of the Study:

• To investigate integrative computations in the auditory midbrain during behavior.
• To determine if inferior colliculus (IC) neurons represent a joint code of sensory, action, and outcome variables.
• To explore the role of the auditory midbrain in complex auditory tasks.

Main Methods:

• Cellular-resolution two-photon calcium imaging in the superficial shell layers of the mouse inferior colliculus (IC).
• Behavioral paradigm: head-fixed mice performing a reward-based psychometric auditory task.
• Analysis of neural population activity in relation to auditory cues, actions, and trial outcomes.

Main Results:

• Individual shell IC neurons exhibit activity reflecting auditory cues, mouse actions, and task outcomes.
• Neural population activity trajectories diverge based on the mouse's behavioral choice.
• Classifier models trained on pre-action neural activity can predict trial outcomes.

Conclusions:

• Auditory midbrain neurons in the IC encode a joint representation of sound, actions, and task-dependent variables.
• The shell IC contributes to integrating sensory information with behavioral context and outcomes.
• This population code in the auditory midbrain supports complex auditory-guided behavior.