Submitted on April 15, 2008
Revised on June 1, 2008
Accepted on August 10, 2008
Low alcohol doses reduce common 10-15 Hz input to bilateral leg muscles during quiet standing
Tjeerd Willem Boonstra1*, Melvyn Roerdink2, Andreas Daffertshofer3, Bram van Vugt4, Guido van Werven4, and Peter Jan Beek2
1 University of New South Wales
2 Vrije Universiteit Amsterdam
3 Vrije Universiteit, Amsterdam
4 VU University Amsterdam
* To whom correspondence should be addressed. E-mail: t.boonstra{at}unsw.edu.au.
The effects of low doses of alcohol on neural synchronization in muscular activity were investigated in ten participants during quiet standing with eyes open or closed. We focused on changes in common input to bilateral motor unit pools as evident in surface EMG recordings of lower leg extensor and flexor muscles. The extensor muscles exhibited bilateral synchronization in two distinct frequency bands, i.e., 0-5 and 10-15 Hz, whereas synchronization between flexor muscles was minimal. As expected, alcohol ingestion affected postural sway yielding increased sway at higher blood-alcohol levels. Whereas vision only affected bilateral synchronization at 0-5 Hz, alcohol ingestion resulted in a progressive decrease of synchronization at 10-15 Hz between the EMG activities of the extensor muscles. The decrease in common bilateral input is most likely related to reduced reticulospinal activity with alcohol ingestion.
