TITLE
Cortical Inhibition within Motor and Frontal Regions in Alcohol Dependence Post-Detoxification: A Pilot TMS-EEG Study
AUTHORS
Naim-Feil J; Bradshaw JL; Rogasch NC; Daskalakis ZJ; Sheppard DM; Lubman DI; Fitzgerald PB. Institution Naim-Feil, Jodie. a Monash Alfred Psychiatry Research Centre, The Alfred and Monash University, Central Clinical School, Prahran, Victoria, Australia. Naim-Feil, Jodie. b School of Psychology and Psychiatry, Monash University, Clayton, Victoria, Australia. Naim-Feil, Jodie. c Department of Physics of Complex Systems, The Weizmann Institute of Science, Rehovot, Israel. Bradshaw, John L. b School of Psychology and Psychiatry, Monash University, Clayton, Victoria, Australia. Rogasch, Nigel C. a Monash Alfred Psychiatry Research Centre, The Alfred and Monash University, Central Clinical School , Prahran, Victoria , Australia. Rogasch, Nigel C. d Brain and Mental Health Laboratory, School of Psychological Sciences and Monash Biomedical Imaging, Monash University, Melbourne, Australia. Daskalakis, Zafiris J. e Temetry Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, University of Toronto, Toronto, Canada. Sheppard, Dianne M. f Monash Injury Research Institute, Monash University, Clayton, Victoria, Australia. Lubman, Dan I. g Turning Point Alcohol and Drug Centre, Eastern Health and Monash University, Victoria, Australia. Fitzgerald, Paul B. a Monash Alfred Psychiatry Research Centre, The Alfred and Monash University, Central Clinical School, Prahran, Victoria, Australia.
SOURCE
World Journal of Biological Psychiatry. 17(7):547-56, 2016 Oct.
OBJECTIVES
Preclinical studies suggest that cortical alterations within the prefrontal cortex (PFC) are critical to the pathophysiology of alcohol dependence. Combined transcranial magnetic stimulation (TMS) and electroencephalography (EEG) allows direct assessment of cortical excitability and inhibition within the PFC of human subjects. We report the first application of TMS-EEG to measure these indices within the PFC of alcohol-dependent (ALD) patients post-detoxification.
METHODS
Cortical inhibition was assessed in 12 ALD patients and 14 healthy controls through single and paired-pulse TMS paradigms. Long-interval cortical inhibition indexed cortical inhibition in the PFC. In the motor cortex (MC), short- interval intracortical inhibition and cortical silent period determined inhibition, while intracortical facilitation measured facilitation, resting and active motor threshold indexed cortical excitability.
RESULTS
ALD patients demonstrated altered cortical inhibition across the bilateral frontal cortices relative to controls. There was evidence of altered cortical excitability in ALD patients; however, no significant differences in MC inhibition.
CONCLUSIONS
Our study provides first direct evidence of reduced cortical inhibition in the PFC of ALD patients post-detoxification. Altered cortical excitability in the MC may reflect hyper-excitability within the cortex associated with chronic alcohol consumption. These findings provide initial neurophysiological evidence of disrupted cortical excitability within the PFC of ALD patients.
