title: A delayed class of BOLD waveforms associated with spreading depression in the feline cerebral cortex can be detected and characterised using independent component analysis (ICA).
abstract: An application of independent component analysis to blood oxygenation level- dependent MRI (BOLD-MRI) results was used to detect cerebrovascular changes that followed the initiation of cortical spreading depression (CSD) in feline brain. The cortical images were obtained from a horizontal plane at 28 s intervals before, and for 1.4-1.75 h after, KCl dissolved in agar (KCl/agar) had been directly applied to the left suprasylvian gyrus of 13 anesthetized cats for 10 min. It successfully resolved, for the first time, a novel class of prolonged, and delayed, biphasic BOLD waveforms. These were larger in amplitude ( approximately 20%), longer lasting and more delayed in onset (13-33 min) than the brief propagating (90 s) BOLD increase ( approximately 4%) already known to be associated with CSD on earlier occasions. Furthermore, such changes occurred in localized regions on the hemisphere ipsilateral to the site of stimulus application in 4 out of 5 control subjects rather than themselves generating propagating waves. Finally, the biphasic waveforms were consistently abolished in the 4 experimental animals studied following the i.v. administration of sumatriptan (0.3 mg kg(-1)), an antimigraine 5-HT(1B/1D) agonist, 15 min before the application of the transient stimulus. They were abolished in 2 out of 4 animals following the intraperitoneal (i.p.) administration of SB-220453 (tonabersat: 10 mg kg(-1), 90 min before stimulus application), a novel anticonvulsant that has recently been reported to inhibit CSD. ICA has thus been successful in detecting a novel localized, as opposed to propagating, signal of potential physiological significance hidden in complex BOLD- MRI data, whose sensitivity to sumatriptan may relate it to the cerebrovascular changes reported in the headache phase of migraine.
authors.affiliation: Physiological Laboratory, University of Cambridge, Downing Street, CB2 3EG Cambridge, UK.
authors.forename: Chaiyapoj
authors.initials: C
authors.lastname: Netsiri
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Bradley
authors.forename: Tsunehiro
authors.initials: T
authors.lastname: Takeda
authors.forename: Martin I
authors.initials: MI
authors.lastname: Smith
authors.forename: Nikolas
authors.initials: N
authors.lastname: Papadakis
authors.forename: Laurance D
authors.initials: LD
authors.lastname: Hall
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Parsons
authors.forename: Michael F
authors.initials: MF
authors.lastname: James
authors.forename: Christopher L-H
authors.initials: CL
authors.lastname: Huang
mesh_terms: D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology; D016477:Artifacts; D001549:Benzamides / Q000494:pharmacology; D001578:Benzopyrans / Q000494:pharmacology; D002415:Cats; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology; D013181:Cortical Spreading Depression / Q000187:drug effects / Q000502:physiology*; D005260:Female; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058825:Serotonin 5-HT1 Receptor Agonists; D018170:Sumatriptan / Q000494:pharmacology
chemical_list: D000927:Anticonvulsants; D001549:Benzamides; D001578:Benzopyrans; D058825:Serotonin 5-HT1 Receptor Agonists; C118706:tonabersat; D018170:Sumatriptan