Drinking related direct current positive potential shift in the human EEG depends on thirst.
Scalp recorded direct current (DC)-potential shifts were examined in 11 human subjects who had either thirsted for 16 h or had quenched thirst before recordings. The recording epoch included a 3-min baseline, an interval of about 5 min during which subjects drank 400 ml of water, and a 7-min post-drinking interval. Consistent with previous data, when thirsty, subjects displayed a widespread negative DC-potential shift during drinking which was replaced by a positive DC shift at the transition to the post-drinking interval. The positivity after drinking lasted for about 2 min and averaged 146 microV at frontal recording sites. Quenching thirst before recordings reduced the positive DC-potential shift upon drinking, whereas changes in preceding drinking related DC negativity appeared to be secondary. The post-drinking positive DC-potential shift depending on the subject's motivational state can be considered an indicator of reward associated with quenching thirst, pointing to a lowered frontocortical excitability during reward.
Hallschmid
M
M
Clinical Neuroendocrinology, Medical University of Lübeck, Ratzeburger Allee 160, Haus 23a, 23538 Lübeck, Germany. hallschmid@kfg.mu-luebeck.de
Mölle
M
M
Wagner
U
U
Fehm
H L
HL
Born
J
J
D000328:Adult; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology*; D004326:Drinking / Q000502:physiology*; D004569:Electroencephalography; D004576:Electromyography; D004585:Electrooculography; D005071:Evoked Potentials / Q000502:physiology*; D005133:Eye Movements / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000502:physiology; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012201:Reward; D013894:Thirst / Q000502:physiology*