Contribution of somatosensory cortex to evoked cerebellar blood flow responses.
Projections from the trigeminocerebellar pathway and the somatosensory cortex coincide spatially in the granule cell layer of Crus I/II of the cerebellar hemisphere. A biphasic field potential was seen: one peak at 10 ms (trigeminal input) and another at 20 ms (somatosensory input). Linear correlation analysis revealed only a weak coupling between somatosensory input and cerebellar blood flow responses to infraorbital nerve stimulation. In separate experiments, cortical spreading depression attenuated the field potential peak at 20 ms while blood flow responses remained unaltered. Thus, trigeminocerebellar activity explained the evoked blood flow responses. Our data provide further evidence that activity-dependent blood flow responses are context-sensitive and that interaction between excitatory neuronal circuits targeting the same cells may occlude vascular responses.
Piilgaard
Henning
H
Department of Medical Physiology, Panum Institute, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark. hphansen@mfi.ku.dk
Lauritzen
Martin
M
D000200:Action Potentials / Q000502:physiology; D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D001808:Blood Vessels / Q000294:innervation / Q000502:physiology; D002525:Cerebellar Cortex / Q000098:blood supply / Q000166:cytology / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D013181:Cortical Spreading Depression / Q000502:physiology; D004558:Electric Stimulation; D008297:Male; D009431:Neural Conduction / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013003:Somatosensory Cortex / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology; D014276:Trigeminal Nerve / Q000502:physiology*