title: Hyperthermia does not alter the increase in cerebral perfusion during cognitive activation.
abstract: This study tested the hypothesis that hyperthermia attenuates the increase in cerebral perfusion during cognitive activation. Mean middle cerebral artery blood velocity (MCAV(mean)) served as an index of cerebral perfusion, while the nBack test (a test of working memory) was the cognitive task. Hyperthermia was characterized by elevations (P < 0.001) in skin (by 5.0 ± 0.8 °C) and intestinal temperatures (by 1.3 ± 0.1 °C) and reductions (P < 0.020) in mean arterial pressure (by 11 ± 10 mmHg), end-tidal CO2 tension (by 3 ± 6 mmHg) and MCAV(mean) (by 10 ± 9 cm s(-1)). Hyperthermia had no influence on nBack test performance (mean difference from normothermia to hyperthermia, -1 ± 11%; P = 0.276) or, counter to the hypothesis, the increase in MCAV(mean) during nBack testing (mean difference from normothermia to hyperthermia: 0 ± 16 cm s(-1); P = 0.608). These findings indicate that the capacity to increase cerebral perfusion during cognitive activation is unaffected by hyperthermia.
authors.affiliation: C. G. Crandall: Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Dallas, TX 75231, USA. craigcrandall@texashealth.org.
authors.forename: Zachary J
authors.initials: ZJ
authors.lastname: Schlader
authors.forename: Rebekah A I
authors.initials: RA
authors.lastname: Lucas
authors.forename: James
authors.initials: J
authors.lastname: Pearson
authors.forename: Craig G
authors.initials: CG
authors.lastname: Crandall
mesh_terms: D000328:Adult; D062186:Arterial Pressure; D001783:Blood Flow Velocity / Q000502:physiology; D001831:Body Temperature / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D005334:Fever / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D020768:Middle Cerebral Artery / Q000502:physiology*