It is commonly accepted that unconsciously perceived masked priming stimuli can trigger partial activation of motor responses or recognition processes. It has been shown in numerous studies that reaction times for compatible trials (primes and targets call for the same responses) are shorter than for incompatible trials for short prime-target temporal distances. On the contrary, for long prime-target temporal distances reaction times for compatible trials are longer than for incompatible trials.

Subliminal priming of motor reaction is rarely used in clinical studies of patients with neuropsychiatric disorders.

To test whether pattern of responses in subliminal priming of motor reaction task differs between healthy controls, alcohol dependent people and Parkinson's disease patients.

Participants from four groups were examined:Parkinson's disease patients, alcohol dependent patients, young healthy controls and elderly controls. Subliminal priming of motor reaction task was used.

It was found that reaction time to subliminal visual stimuli in individuals from different groups varies. A specific pattern of responses was observed for each group. Reaction times were the shortest in the group of young controls and the longest in Parkinson's disease patients. Processing visual stimuli in alcohol dependent people and Parkinson's disease patients seems to have different mechanism in comparison to healthy controls.

Analysis of mean reaction times during presentation of compatible and incompatible trials allows to differentiate examined groups at quantitative and qualitative level. Differences between particular groups (especially alcohol dependent and Parkinson's disease patients) may contribute to better understanding and diagnosis of the diseases.