Hyperthermia impairs short-term memory and peripheral motor drive transmission

Racinais, S., Gaoua, N. and Grantham, J. (2008) Hyperthermia impairs short-term memory and peripheral motor drive transmission. The Journal of Physiology, 586 19: 4751-4762. doi:10.1113/jphysiol.2008.157420

Author Racinais, S.
Gaoua, N.
Grantham, J.
Title Hyperthermia impairs short-term memory and peripheral motor drive transmission
Journal name The Journal of Physiology   Check publisher's open access policy
ISSN 1469-7793
Publication date 2008-10
Sub-type Article (original research)
DOI 10.1113/jphysiol.2008.157420
Volume 586
Issue 19
Start page 4751
End page 4762
Total pages 12
Place of publication London, U.K.
Publisher Blackwell for the Physiological Society
Language eng
Subject 0606 Physiology
1116 Medical Physiology
Formatted abstract
 The aims of this study were to determine (i) the effect of passive hyperthermia on motor drive and cognitive function, and (ii) whether head cooling can limit the hyperthermia-induced alterations. Sixteen subjects were randomly exposed for 2 h to three different conditions: control (Con, 20°C), hot (Hot, 50°C) and hot head cool (HHC – where cold packs were applied to the head under Hot conditions). Three cognitive tests measuring attention and two measuring memory were performed. Neuromuscular testing included electrically evoked muscle action potentials (M-waves) and reflex waves (H-reflex) at rest and during brief (4–5 s) and sustained (120 s) maximal voluntary contractions (MVC) of the plantar flexors. All the tests were performed in the environmental room. During brief MVC, torque was significantly lower in both Hot and HHC as compared to Con (P< 0.05). The decrease in muscle activation was significant in Hot (P < 0.05) but not in HBC (P = 0.07). This was accompanied by peripheral failures in the transmission of the neural drive at both spinal (significant decrements in H-reflexes and V-waves, P < 0.05) and neuromuscular junction (significant decrements in M-waves, P < 0.05) levels. During sustained MVC, muscle activation was further depressed (P < 0.05) without any concomitant failures in M-waves, suggesting neural activation adjustments occurring probably at the supraspinal level. Cerebral perturbations were confirmed by significant decrements in both memory tests in Hot as compared with Con (P < 0.05) but not in simple tests (attention tests) that were not affected by hyperthermia. The decrement in memory capacity suggested the existence of frontal lobe activity impairments. Thus, HHC preserved memory capacity but not the visual memory.
Keyword Hyperthermia
Short term memory
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Human Movement and Nutrition Sciences Publications
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