title: Influence of physiological changes of glycaemia on VEPs and visual ERPs.
abstract: Since hypoglycemia is known to influence cognitive functions, we checked whether the physiological changes in glycemia (after fasting or exertion) can explain the rather high intra-individual variability of event-related potentials (ERPs). Besides the ERPs to "change in coherence of a moving pattern" with reaction time (RT) recording, binocular pattern reversal VEPs and motion-onset VEPs (to linear and radial motion) were also examined in 14 healthy subjects prior to and after 24-h fasting that decreased glycemia from 5.3 to 3.9 mmol/l on the average. We only found one significant change in the latencies and amplitudes of VEPs and ERPs (with no change of RT). The N160 peak in the motion-onset VEPs to radial (expansive) motion (EM-VEPs) showed a larger amplitude at lower glycemia. For evaluation of the exertion influence, we tested glycemia prior to and after 90 min long exercise -- bicycle ergometry with the load set to 2 W/kg in women and 2.5 W/kg in men (average age-related values for W170/kg index). The changes of glycemia to exertion were, however, less distinct than those to fasting. We conclude that in healthy subjects the glycemia decrease due to 24-h fasting or intensive time-limited exercise never reaches the critical value to change the VEP, ERPs and RTs.
authors.affiliation: Department of Pathophysiology, Charles University, Faculty of Medicine in Hradec Králové, Simkova 870, 50038 Hradec Králové, Czech Republic. kubova@lfhk.cuni.cz
authors.forename: Z
authors.initials: Z
authors.lastname: Kubová
authors.forename: J
authors.initials: J
authors.lastname: Chlubnová
authors.forename: J
authors.initials: J
authors.lastname: Szanyi
authors.forename: M
authors.initials: M
authors.lastname: Kuba
authors.forename: J
authors.initials: J
authors.lastname: Kremlácek
mesh_terms: D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000502:physiology; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005080:Exercise Test / Q000379:methods; D005215:Fasting / Q000502:physiology; D005260:Female; D038321:Glycemic Index / Q000502:physiology*; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D011930:Reaction Time / Q000502:physiology
chemical_list: D001786:Blood Glucose