Feedback optimizes neural coding and perception of natural stimuli.

Area of Science:

• Neuroscience
• Sensory processing
• Computational neuroscience

Background:

• Sensory neurons are thought to optimize information processing by tuning to natural stimulus statistics.
• The neural mechanisms enabling this optimization, particularly the role of feedback, remain largely unknown.

Purpose of the Study:

• To investigate the mechanisms by which feedback pathways mediate optimized neural encoding of naturalistic stimuli.
• To determine if temporal whitening, a form of spectral equalization, is involved in this process.

Main Methods:

• Electrophysiological recordings in the weakly electric fish, *Apteronotus leptorhynchus*.
• Analysis of neural responses to naturalistic stimuli and spectral properties.
• Investigation of direct and indirect feedback pathways from higher brain areas.

Main Results:

• Descending feedback pathways differentially modulate neural responses.
• Indirect feedback selectively attenuates low-frequency responses, creating a high-pass tuning curve.
• Higher brain neurons exhibit both broadband and high-pass tuning, performing temporal whitening.

Conclusions:

• Descending input plays a critical role in optimizing sensory neuron responses to natural stimuli through temporal whitening.
• This mechanism enhances neural encoding by counteracting the decaying spectral power of natural stimuli.
• The findings suggest a conserved mechanism for sensory processing across species.