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[Inhibition with light flashes of negative delta-waves in the rabbit visual cortex]
Abstract:
To elucidate the nature of negative and positive phases of background delta-waves (BDW), their interaction with evoked potentials was studied in the rabbit visual cortex. BDW appeared after injection of drugs synchronizing ECoG: amyzyl, aminozin, barbiturates, and during asphyxia. The flashes evoked slow positive responses lasting about 0.5 to 1.0 s. These responses blocked the negative BDW. The results of the study and published data suggest that background delta-activity consists of segments which reflect the desynchronized state and correspond to positive BDW, and of segments which reflect active inhibition in the cerebral cortex and correspond to negative BDW.
Insights
Background delta-waves (BDW) in rabbit visual cortex involve positive and negative phases. Positive BDW correlate with desynchronization, while negative BDW indicate cortical inhibition, blocking evoked potentials.
Area of Science:
- Neuroscience
- Cortical electrophysiology
- Sleep and anesthesia research
Context:
- Background delta-waves (BDW) are prominent in electrocorticography (ECoG).
- Understanding BDW phases is crucial for interpreting cortical states.
- Previous studies linked BDW to synchronized ECoG activity.
Purpose:
- To investigate the nature of positive and negative phases of background delta-waves (BDW).
- To examine the interaction between BDW and evoked potentials in the rabbit visual cortex.
- To differentiate the neural correlates of positive and negative BDW.
Summary:
- BDW were induced using synchronizing drugs (amyzyl, aminozin, barbiturates) and asphyxia in rabbits.
- Evoked potentials, elicited by flashes, manifested as slow positive responses (0.5-1.0 s).
- These evoked responses effectively blocked the negative phase of BDW, suggesting an inhibitory mechanism.
Impact:
- Suggests positive BDW segments reflect cortical desynchronization.
- Indicates negative BDW segments correspond to active cortical inhibition.
- Provides insights into the dynamic interplay between cortical activity and inhibition.