Control of reaction time performance involves the striatum

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Thalamic and Basal Ganglia Function

Background:

• The centre median nucleus (CM) of the thalamus and the caudate nucleus (Cd) of the basal ganglia are implicated in motor control and cognitive functions.
• Understanding the specific roles of these structures in reaction time tasks is crucial for deciphering motor deficits.

Purpose of the Study:

• To investigate the causal role of unilateral CM and Cd cooling on simple reaction time performance in cats.
• To compare the effects of CM and Cd cooling on reaction time and performance consistency.
• To explore potential parallels between experimental cooling effects and human neurological conditions like Parkinson's disease.

Main Methods:

• Cats were trained on a simple reaction time schedule.
• Unilateral cooling of the CM or Cd was applied during task performance.
• Reaction time, trial rate, and performance consistency were measured.
• Human subjects with Parkinson's disease performed the same reaction time schedule.

Main Results:

• Unilateral CM cooling resulted in a significant shortening of reaction time.
• Unilateral Cd cooling led to a lengthening of reaction time.
• Cd cooling also caused a dose-dependent decrease in trial rate and performance arrest.
• Human subjects with Parkinson's disease exhibited prolonged reaction times and impaired performance reliability.

Conclusions:

• The CM appears to modulate reaction time, potentially facilitating faster responses.
• The Cd plays a critical role in maintaining performance rate and consistency, with cooling inducing deficits reminiscent of Parkinsonian motor impairments.
• These findings highlight distinct functional contributions of the CM and Cd to motor control and reaction time performance.