Office of Aerospace Medicine Technical Reports
FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute
Report No: DOT/FAA/AM-78/2
Title and Subtitle: Effects of ethanol on visual unit activity in the thalamus
Report Date: January 1978
Authors: Revzin AM
Abstract: The investigator studied the effects of ethanol on the spontaneous activity of single neurons in functionally differentiated subnuclei of a posterior thalamic visual projection area, nucleus rotundus, in the anesthetized pigeon. Low doses of ethanol, 0.05 - 0.10 ml/kg (producing blood levels of about 0.005 - 0.010%) , inhibited activity in anterior rotundus but had complex excitatory-inhibitory effects on posterior rotundal cells. Nonvisual dorsal thalamic cells, and 'lateral geniculate' neurons were inhibited by ethanol but threshold doses (0.25 - 0.40 ml/kg) were far higher than those for the rotundal cells (0.05 ml/kg).
These differing dose-response curves for visual and nonvisual thalamic neurons suggest:
Thus, the notorious unpredictability of ethanol-induced changes in behavior or task performance may be the inevitable consequence of the reported differential dose-response effects on single neurons.
Key Words: Ethanol, Toxicology, Vision, Posterior thalamus, Unit activity, Transportation safety
No. of Pages: 9
Civil Aerospace Medical Institute
Report No: DOT/FAA/AM-78/2
Title and Subtitle: Effects of ethanol on visual unit activity in the thalamus
Report Date: January 1978
Authors: Revzin AM
Abstract: The investigator studied the effects of ethanol on the spontaneous activity of single neurons in functionally differentiated subnuclei of a posterior thalamic visual projection area, nucleus rotundus, in the anesthetized pigeon. Low doses of ethanol, 0.05 - 0.10 ml/kg (producing blood levels of about 0.005 - 0.010%) , inhibited activity in anterior rotundus but had complex excitatory-inhibitory effects on posterior rotundal cells. Nonvisual dorsal thalamic cells, and 'lateral geniculate' neurons were inhibited by ethanol but threshold doses (0.25 - 0.40 ml/kg) were far higher than those for the rotundal cells (0.05 ml/kg).
These differing dose-response curves for visual and nonvisual thalamic neurons suggest:
- low doses of ethanol may seriously impair peripheral visual functions;
- The behavioral effects of ethanol are highly dose-dependent;
- Effects of low doses of ethanol may not be extrapolated from high-dose effects since high-dose effects may mask effects dominant at low doses;
- The effects of a given dose of ethanol may vary widely and unpredictably among individuals.
Thus, the notorious unpredictability of ethanol-induced changes in behavior or task performance may be the inevitable consequence of the reported differential dose-response effects on single neurons.
Key Words: Ethanol, Toxicology, Vision, Posterior thalamus, Unit activity, Transportation safety
No. of Pages: 9
Last updated: Friday, June 1, 2012