Feedback generates a second receptive field in neurons of the visual cortex

Area of Science:

• Neuroscience
• Visual System Processing
• Sensory Neuroscience

Background:

• Sensory pathways link organs to the brain, defining classical receptive fields (ffRF) for stimulus excitation.
• Neurons can be excited by stimuli outside their ffRF, suggesting context-dependent processing, but mechanisms remain unclear.

Purpose of the Study:

• To elucidate the mechanisms generating neuronal excitation by stimuli outside the classical feedforward receptive field (ffRF).
• To characterize a newly identified feedback receptive field (fbRF) in the mouse visual cortex.

Main Methods:

• Investigated feedback projections onto excitatory neurons in the mouse primary visual cortex.
• Stimulated both ffRF and fbRF to compare response characteristics.
• Utilized anesthesia and silencing of higher visual areas to assess response modulation.
• Examined receptive field properties of feedback inputs and neuronal location across cortical layers.

Main Results:

• Feedback projections create a second receptive field (fbRF) driven by stimuli outside the ffRF.
• fbRF stimulation elicits slower, delayed responses compared to ffRF stimulation.
• Responses are reduced by anesthesia and silencing of higher visual areas.
• fbRF and ffRF are mutually antagonistic, with specific inhibitory neuron populations showing differential responses.

Conclusions:

• The fbRF complements the ffRF, enabling neurons to use visual context for predictive processing.
• Feedback projections contribute to estimating missing information and detecting stimulus feature differences across visual space.
• The fbRF mechanism is crucial for integrating contextual information in the visual system.