Differences in mental task performance and slow potential shifts in subjects differing in cortisol level

Area of Science:

• Neuroendocrinology
• Psychophysiology
• Cognitive Psychology

Background:

• The pituitary-adrenocortical axis, including cortisol, influences brain function.
• Individual differences in cortisol baselines may correlate with physiological and cognitive responses.

Purpose of the Study:

• To investigate the relationship between baseline cortisol levels and heart rate, brain potentials, task performance, and personality traits.
• To compare psychophysiological and performance differences between high and low cortisol responders under stress.

Main Methods:

• 17 males performed arithmetic tasks under time stress and control conditions.
• Plasma cortisol levels were measured using radioimmunoassays.
• Heart rate, slow brain potential shifts (SPS), and performance data were recorded.
• Participants were categorized into high (HC) and low (LC) cortisol responder groups.

Main Results:

• The high cortisol (HC) group exhibited significantly higher heart rate.
• The low cortisol (LC) group showed distinct slow brain potential shifts (SPS), including a larger P300 and increased negative slow wave (NSW).
• The LC group performed tasks faster, earned more rewards, and reported higher achievement motivation, social acceptance, and lower tiredness.

Conclusions:

• Low cortisol responders (LC) appear to regulate arousal more efficiently than high cortisol responders (HC).
• Cortisol baseline levels are associated with distinct psychophysiological and performance profiles under stress.
• Findings suggest a link between endocrine regulation and cognitive-emotional efficiency.