Visual evoked feedforward-feedback traveling waves organize neural activity across the cortical hierarchy in mice

Sensory processing is distributed among many brain regions that interact via feedforward and feedback signaling. Neuronal oscillations have been shown to mediate intercortical feedforward and feedback interactions. Yet, the macroscopic structure of the multitude of such oscillations remains unclear. Here, we show that simple visual stimuli reliably evoke two traveling waves with spatial wavelengths that cover much of the cerebral hemisphere in awake mice. 30-50 Hz feedforward waves arise in primary visual cortex (V1) and propagate rostrally, while 3-6 Hz feedback waves originate in the association cortex and flow caudally. The phase of the feedback wave modulates the amplitude of the feedforward wave and synchronizes firing between V1 and parietal cortex. Altogether, these results provide direct experimental evidence that visual evoked traveling waves percolate through the cerebral cortex and coordinate neuronal activity across broadly distributed networks mediating visual processing. Processing sensory stimuli requires coordinated activation of neurons broadly distributed across many distant cortical sites, yet it is not clear how this coordination is accomplished in the brain. Here, the authors show that visual stimuli reliably evoke traveling waves of activity that percolate through the cortex and orchestrate neuronal firing across primary visual and association cortices.

Automated summary

Sensory processing involves interaction between various brain regions through feedforward and feedback signaling. This study demonstrates that visual stimuli elicit traveling waves of activity in awake mice, with 30-50 Hz feedforward waves originating in the primary visual cortex and propagating forward, while 3-6 Hz feedback waves originate in the association cortex and propagate backward. The phase of the feedback wave modulates the amplitude of the feedforward wave and synchronizes firing across different cortical areas.