title: Re-entry waves of Leao's spreading depression between neocortex and caudate nucleus.
abstract: About 40% of spreading depression (SD) waves elicited from the parieto-occipital cortex of anesthetised rats penetrated through the temporal lobe structures (amygdala) into the caudate nucleus. Almost 70% of these SD waves did not terminate in the caudate but returned to the cortex and spread through it toward the site of SD initiation. Longer cortico-caudate (5.9 +/- 0.1 min) than caudate-cortical (4.7 +/- 0.2 min) conduction times suggest that SD enters and leaves caudate through routes of different length. SD waves elicited by KCl microinjection into the caudate reached frontal and parieto-occipital cortical electrodes with latencies indicating that the transit point is 5 mm closer to the rostral than to the caudal electrode. The region best satisfying this condition corresponds to rostral claustrum. The directionally biased SD conduction through the transit zone provides a re-entry path for cortico-caudate-cortical SD propagation and forms thus a natural reverberator the small dimensions of which preclude generation of repetitive SD waves.
authors.affiliation: Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow.
authors.forename: L V
authors.initials: LV
authors.lastname: Vinogradova
authors.forename: V I
authors.initials: VI
authors.lastname: Koroleva
authors.forename: J
authors.initials: J
authors.lastname: Bures
mesh_terms: D000818:Animals; D002421:Caudate Nucleus / Q000033:anatomy & histology / Q000502:physiology*; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology*; D013181:Cortical Spreading Depression; D004558:Electric Stimulation; D005071:Evoked Potentials; D009778:Occipital Lobe / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology; D051381:Rats