Heavy alcohol use in adolescence is associated with altered cortical activity: a combined TMS–EEG study

Abstract

Long-term alcohol use affects cognitive and neurophysiological functioning as well as structural brain development. Combining simultaneous electroencephalogram (EEG) recording with transcranial magnetic stimulation (TMS) enables direct, in vivo exploration of cortical excitability and assessment of effective and functional connectivity. In the central nervous system, the effects of alcohol are particularly mediated by alterations in gamma-aminobutyric acid (GABA)ergic neurotransmission, and TMS-evoked potentials (TEPs) N45 and N100 in EEG are known to reflect GABAergic function. However, no previous studies have examined the effects of long-term alcohol use in adolescence on TEPs. In this study, a total of 27 young adults with heavy alcohol use in adolescence and 25 age-matched, gender-matched and education-matched controls with little or no alcohol use participated in TMS-EEG measurements. The motor cortex (M1) was stimulated with an intensity of 90 percent of the resting motor threshold of the abductor pollicis brevis muscle. No significant differences were found in the resting motor threshold, TEP latencies or neuropsychological functioning between the groups. We observed an increase in the global mean field power in the time window of 54- to 75-millisecond post-TMS, as well as significant topographical differences in the P60 and N100 in those with a history of heavy drinking. Furthermore, there was a marked increase in the GABAergic N45 amplitude in alcohol users. These findings suggest that long-term alcohol use in adolescence, even when not meeting the diagnostic criteria for a disorder, is associated with changes in connectivity and cortical excitability.

Changes in the serum metabolite profile correlate with decreased brain gray matter volume in moderate-to-heavy drinking young adults

“…When considering genders separately, these correlations were robust in females, as shown in B and E. In male subjects, these correlations were not significant (C and F). laboratory detected altered GABAergic activity in the brains of the same group of moderate-to-heavy drinking participants in an earlier study (Kaarre et al, 2018).…”

“…In this study, we compared moderate-toheavy drinking and light-drinking young adults, and investigated 1) differences in metabolic profiles and 2) correlations between metabolic profiles and gray matter volumes. Previously, we have reported detailed descriptions of changes in brain morphometry and cortical activity in the same subjects (Heikkinen et al, 2017;Kaarre et al, 2018).…”

Modulating Neural Circuits with Transcranial Magnetic Stimulation: Implications for Addiction Treatment Development

“…In healthy controls, acute alcohol exposure enhances LTD-like plasticity (Fuhl et al, 2015) but blocks LTP-like effects (Lucke et al, 2014;Loheswaran et al, 2016). In multiple studies, neither acute alcohol administration nor a history of chronic alcohol use had an effect on resting or active motor threshold (Ziemann et al, 1995;Conte et al, 2008;Nardone et al, 2010a,b;Kaarre et al, 2018), although one group did find a small difference between healthy controls and those with an alcohol use disorder when controlling for depression and intellectual function (Naim-Feil et al, 2016).…”

The Influence of Recreational Substance Use in TMS Research

“…Alcohol-dependents exhibit reduced RMT, AMT, and MEPs compared to healthy controls [ 30 , 32 ]. In contrast, other studies report no chronic-related effects on RMT, AMT or MEPs [ 23 , 28 , 31 ]. Importantly, Naim-Feil et al [ 30 ] recruited participants on the basis that they had successfully completed a detoxification program within the past two years.…”

“…In young adults who exhibited alcohol-dependence in adolescence, TMS-evoked N45 potentials were larger compared to controls [ 31 ]. This suggests an upregulation of GABA A R activity [ 35 ], which does not follow the expected chronic effects of alcohol [ 9 , 10 , 47 ].…”