Response selection and initiation in speeded reactions: a pupillometric analysis.

Area of Science:

• Cognitive Neuroscience
• Psychophysiology

Background:

• The task-evoked pupillary response (TEPR) is a psychophysiological measure sensitive to cognitive and motor processes.
• Understanding TEPR's contribution to simple and disjunctive reaction tasks can elucidate performance mechanisms.

Purpose of the Study:

• To investigate the role of TEPR as a measure of motor and cognitive performance in simple and disjunctive reaction tasks.
• To analyze pupillary dilation patterns during different response conditions and their relation to cognitive load and motor preparation.

Main Methods:

• Recording pupillary responses during simple and disjunctive reaction time tasks.
• Manipulating stimulus-response conditions, including "Go" and "No-Go" trials, and response delays.
• Analyzing pupillary dilation onset, peak, rate, and amplitude in relation to task demands.

Main Results:

• In simple reactions, pupillary dilation preceded the stimulus, influenced by interstimulus interval.
• Disjunctive reactions showed distinct dilations for "Go" and "No-Go" responses, with "No-Go" dilations being smaller and reduced by response delays.
• Pupillary response related to response selection was estimated at 55% of motor preparation and execution; response probability affected "No-Go" dilation amplitude.

Conclusions:

• TEPR provides valuable insights into both motor preparation and cognitive processes like response selection.
• Data suggest significant preparatory motor processing in "No-Go" reactions and overlap between decisional and motoric processing in disjunctive tasks.
• Pupillometry offers a sensitive, non-invasive method for assessing complex cognitive-motor interactions.