Abstract
Purpose :
Feedforward and feedback signaling are critical for sensory information processing across the cortical hierarchy. In awake mice, simple visual stimuli evoke two traveling waves that span much of a cortical hemisphere: a fast (30-50Hz) feedforward wave and a slow (3-6 Hz) feedback wave. If these waves denote critical elements of visual processing, the delivery of hypnotic doses of anesthesia should impair their propagation patterns.
Methods :
To explore how arousal state affects the spatiotemporal properties of visual evoked responses, we performed high density electrocorticography recordings (128 channels) in mice (n = 32) during wakefulness or under mechanistically distinct anesthetics.
Results :
We demonstrate that simple visual stimuli evoke fast oscillations over the cortical surface in all mice, regardless of anesthetic state. However, attributes of fast feedforward waves including single trial reliability, signal to noise, and spatial activation pattern, are disrupted in drug specific manner. Conversely, visual stimuli fail to evoke large amplitude slow oscillations in animals under any of the anesthetics tested. Moreover, evoked slow waves observed in anesthetized animals resemble those elicited from weak stimuli in awake animals.
Conclusions :
We find that while feedforward waves are affected by the anesthesia in a drug specific manner, feedback waves are abolished by all anesthetic agents tested. Thus, the ability to generate feedback waves might be a unifying signaling pathway necessary for visual perception.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.