Psychobiology of personality

Several personality traits have been examined for their psychobiological relationships. For example, neuroticism is one of the well studies personality traits. A person high on neuroticism is susceptible to anxiety, depression, stress, and so forth. Benzodiazepine potentiates the effect of gama-aminobutyric acid (GABA) which has inhibitory effect on brain nuclei. Decreased amount of benzodiazepine in amygdala is related to high neuroticism. Similarly sensation seeking behaviour is another personality trait that has high social relevance. Those who are high on sensation seeking be likely to be under-aroused. Their Ascending Reticular Activation System (ARAS) is below the optimum level of arousal.

Studies examining autonomic nervous system (ANS) function differences introverts and extroverts have used skin conductance, heart rate and EEG measures. Studies have explored difference between introversion-extraversion and skin conductance level. Skin conductance level has been used to measure tonic arousal in the baseline resting condition or the period prior to stimulation in an experiment. Studies have found that simple sensory stimulation do not elicit any difference between introverts and extraverts in terms of tonic levels of electrodermal activity. However, when challenged by task demands, the s kin conductance level has been found to be higher for extraverts at higher stress levels. Contrarily the skin conductance level was higher in introverts for lower stress levels.