Alcohol Reduces Prefrontal Cortical Excitability in Humans: A Combined TMS and EEG Study

Abstract

The effects of alcohol (0.8 g/kg) on the prefrontal cortex were studied in nine healthy subjects using the technique of transcranial magnetic stimulation (TMS) combined with electroencephalography (EEG). A total of 120 magnetic pulses were delivered with a figureof-eight coil to the left prefrontal cortex at the rate of 0.4-0.7 Hz. The EEG was recorded simultaneously with 60 scalp electrodes (41 electrodes were used for analysis); the TMS-evoked activation was estimated by the area under the global mean field amplitude (GMFA) time curve. TMS caused changes in EEG activity lasting up to 270 ms poststimulus. Alcohol decreased GMFA at 30-270 ms poststimulus (713 7 303 vs 478 7 142 mV ms; p ¼ 0.007). Alcohol-induced differences were most pronounced at anterior electrodes. These results suggest that alcohol reduces the excitability in the prefrontal cortex.

Ethanol Inhibits Persistent Activity in Prefrontal Cortical Neurons

“…Ethanol inhibited persistent activity and spike firing in the slice cocultures and reduced PFC firing in vivo. The concentrations of ethanol that produced these effects (17-100 mM; ϳ0.08 -0.4% blood alcohol concentration) are similar to those that alter PFC-mediated behaviors including working memory, error detection (Melchior et al, 1993;Givens and McMahon, 1997;Ridderinkhof et al, 2002;Rossetti et al, 2002), and EEG responses after stimulation of the frontal cortex in humans (Kahkonen et al, 2003). Ethanol's inhibition of persistent activity in the slice cocultures appeared to involve synaptic sites of action, as even high concentrations of ethanol had little effect on firing evoked by direct current injection.…”

“…For example, ethanol reduces the detection of performance errors as monitored by scalp electrodes and decreases EEG activity evoked by stimulation of the prefrontal cortex (Ridderinkhof et al, 2002;Kahkonen et al, 2003). Long-term alcohol abuse causes changes in gray and white matter volume in the PFC that are correlated with the appearance of neurocognitive deficits (for review, see Sullivan and Pfefferbaum, 2005).…”

Transcranial Magnetic Stimulation-Electroencephalography Responses in Recovered and Symptomatic Mild Traumatic Brain Injury

“…29 Ethanol reduces 30-270 msec global mean field amplitudes, especially evident at N45, reflecting decreased TMS-induced activity. 30,31 Slow repetitive TMS also reduces cortical excitability, which on TMS-EEG is reflected in reduced N45 amplitudes. 23 Paired pulse stimulation with a relatively facilitatory stimulation paradigm with 11-12 msec interstimulus intervals, however, also causes weaker N45 responses, compared with single pulse stimulation.…”

The effect of adequate alcohol intake on the efficiency of second language learning

“…A decrease in functional heterogeneity in the right prefrontal cortex was observed after alcohol consumption [32]. Decreased performance on a verbal fluency task in intoxicated participants was observed to correspond to lateral activation of the left dorsolateral PFC, the area associated with language [33].…”

“…Imaging PFC activity using transcranial magnetic stimulation (TMS) shows that the harmful effects of alcohol are attributed to the breakdown of functional specificity in different brain regions [32]. A decrease in functional heterogeneity in the right prefrontal cortex was observed after alcohol consumption [32].…”