Neural correlates of fast pupil dilation in nonhuman primates: Relation to behavioral performance and cognitive workload

• Published in: Behavioural brain research Vol. 212; no. 1; pp. 1 - 11
• Main Authors: Hampson, R.E., Opris, Ioan, Deadwyler, S.A.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier B.V 01-09-2010; Elsevier
• Subjects: Action Potentials - physiology; Analysis of Variance; Animals; Behavior; Behavioral psychophysiology; Biological and medical sciences; Brain Mapping; Cognition - physiology; Cognitive demand; Delayed-match-to-sample task; Electrophysiology; Eye Movements - physiology; Frontal cortical neurons; Fundamental and applied biological sciences. Psychology; Macaca mulatta - physiology; Male; Monkey; Neurons - classification; Neurons - physiology; Neuropsychological Tests; Nonhuman primate; Oculometrics; Perievent histogram; Photic Stimulation - methods; Prefrontal Cortex - cytology; Primates; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Pupil - physiology; Pupil diameter; Reaction Time - physiology; Rhesus; Sleep Deprivation - physiopathology; Oculometrics; Rhesus; Pupil diameter; Nonhuman primate; Cognitive demand; Monkey; Electrophysiology; Frontal cortical neurons; Perievent histogram; Delayed-match-to-sample task; Behavior; Cognitive ability; Cognition; Pupil; Vertebrata; Delayed response; Mammalia; Neuron; Animal; Primates; Matching task; Diameter
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2010.03.011

Pupil dilation in humans has been previously shown to correlate with cognitive workload, whereby increased frequency of dilation is associated with increased degree of difficulty of a task. It has been suggested that frontal oculomotor brain areas control cognitively related pupil dilations, but this has not been confirmed due to lack of animal models of cognitive workload and task-related pupil dilation. This is the first report of a wavelet analysis applied to continuous measures of pupil size used to detect the onset of abrupt pupil dilations and the frequency of those dilations in nonhuman primates (NHPs) performing a trial-unique delayed-match-to-sample (DMS) task. A unique finding shows that electrophysiological recordings in the same animals revealed firing of neurons in frontal cortex correlated to different components of pupil dilation during task performance. It is further demonstrated that the frequency of fast pupil dilations (but not rate of eye movements) correlated with cognitive workload during task performance. Such correlations suggest that frontal neuron encoding of pupil dilation provides critical feedback to other brain areas involved in the processing of complex visual information.