Cortico-thalamo-cortical interactions modulate electrically evoked EEG responses in mice

Area of Science:

• Neuroscience
• Computational Neuroscience
• Systems Neuroscience

Background:

• Perturbational complexity analysis (PCA) assesses brain complexity to predict consciousness.
• Understanding the neural circuits underlying PCA is crucial for its clinical application.

Purpose of the Study:

• To investigate the neural circuits in mice that generate the EEG complexity observed during PCA.
• To compare brain responses during wakefulness and anesthesia.

Main Methods:

• Direct cortical stimulation in mice.
• Simultaneous electroencephalography (EEG) and Neuropixels probe recordings.
• Analysis of neural activity during wakefulness and isoflurane anesthesia.

Main Results:

• Deep cortical stimulation in awake mice evoked a local excitation, followed by a 120 ms 'off' period and rebound excitation.
• Thalamic nuclei showed a similar pattern, linked to a late EEG component, suggesting cortico-thalamo-cortical involvement.
• This 'off' period and rebound were reduced during locomotion and abolished during anesthesia.

Conclusions:

• Cortico-thalamo-cortical interactions are critical for generating long-lasting EEG signals during deep cortical stimulation in awake states.
• The observed neural dynamics are state-dependent, being diminished during movement and absent under anesthesia.