Interhemispheric asymmetry during NREM sleep in the dog

Area of Science:

• Neuroscience
• Comparative Psychology
• Sleep Science

Background:

• Functional hemispheric asymmetry is observed in various species during sleep.
• While dogs exhibit asymmetry during wakefulness, their sleep-related neural activity remains uninvestigated.

Purpose of the Study:

• To investigate interhemispheric neural asymmetry in family dogs during non-rapid eye movement (NREM) sleep.
• To analyze EEG recordings from dogs during polysomnography to understand sleep brain activity.

Main Methods:

• Utilized non-invasive polysomnography to record EEG from 19 family dogs over two separate nap sessions.
• Focused analysis on the first two sleep cycles of 3-hour afternoon naps to capture high sleep pressure and reduce inter-dog variance.
• Assessed hemispheric asymmetry during NREM sleep using bilateral EEG channels and analyzed specific frequency bands (slow, alpha, sigma, beta).

Main Results:

• A left hemispheric predominance in the slow frequency range was detected in the first sleep cycle of the initial recording.
• Greater absolute hemispheric asymmetry was observed in the alpha, sigma, and beta frequency ranges during the second sleep cycle compared to the first.
• Differences between recordings and sleep cycles suggest potential adaptation processes, though distinct from human patterns.

Conclusions:

• The study provides initial evidence of hemispheric asymmetry in dogs during NREM sleep.
• Findings indicate potential species-specific patterns of neural activity during canine sleep.
• Further research is needed to fully elucidate the nature and implications of hemispheric asymmetry in dogs during sleep.