Cortico-thalamo-cortical interactions modulate electrically evoked EEG responses in mice
Leslie D. Claar, Irene Rembado, Jacqulyn R. Kuyat, Scott J. Russo, Lydia C. Marks, Shawn R. Olsen, Christof Koch
bioRxiv March 28, 2023 preprint DOI: 10.7554/elife.84630 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental animal study |
|---|---|
| Population | Mice |
| Key findings | In awake mice, deep cortical stimulation evokes a brief excitation followed by a 120 ms off period and rebound excitation in cortex and thalamus, with a late EEG component; these responses are reduced during running and absent under isoflurane anesthesia, suggesting cortico-thalamo-cortical interactions underlie consciousness-related EEG complexity. |
Abstract
Perturbational complexity analysis predicts the presence of consciousness in volunteers and patients by stimulating the brain with brief pulses, recording electroencephalographic (EEG) responses, and computing their spatiotemporal complexity. We examined the underlying neural circuits in mice by directly stimulating cortex while recording with EEG and Neuropixels probes during wakefulness and isoflurane anesthesia. When mice are awake, stimulation of deep cortical layers reliably evokes locally a brief pulse of excitation, followed by a bi-phasic sequence of 120 ms profound off period and a rebound excitation. A similar pattern, partially attributed to burst spiking, is seen in thalamic nuclei, and is associated with a pronounced late component in the evoked EEG. We infer that cortico-thalamo-cortical interactions drive the long-lasting evoked EEG signals elicited by deep cortical stimulation during the awake state. The cortical and thalamic off period and rebound excitation, and the late component in the EEG, are reduced during running and absent during anesthesia.