Preliminary findings on the relation between the personality trait of stress reaction and the central neural control of human vocalization

The objectives of this study were to examine whether the personality trait of stress reaction (SR), as assessed with the Multidimensional Personality Questionnaire-Brief Form (MPQ-BF), (1) influences prefrontal and limbic area activity during overt sentence reading and if (2) SR and associated individual differences in prefrontal and limbic activations correlate with sensorimotor cortical activity during overt sentence reading. Ten vocally healthy adults (22-57 years) participated in a functional MRI study using an event-related sparse sampling design to acquire brain activation data during sentence production tasks (covert, whispered, overt). The outcome measure was the blood oxygenation level-dependent signal change in prefrontal, limbic, and primary somatosensory (S1) and motor cortices (M1). Significant positive correlations were found between SR scores and S1, dorsolateral prefrontal cortex (both r =.73, p.05), and periaqueductal gray (r =.88, p.01) activity. M1 activity was positively correlated with SR (r =.64, p.05) and negatively with social potency (r = -.70, p.05). Our findings suggest that motor cortical control subserving voice and speech production varies with expression of selected personality traits. Future studies should investigate the functional significance of personality differences in the central neural control of vocalization.