Enhanced Reactivity and Delayed Recovery of Sensorimotor Cortex in the Novelty Seeking Personality

Abstract

Background: The novelty seeking (NS) personality trait is hypothesized to be associated with high cortical reactivity, poor inhibitory control and/or varied dopaminergic neurotransmission in the basal ganglia. After somatosensory stimulation, electrical oscillations in alpha and beta bands generated in the sensorimotor cortex show a short duration decrease (event-related desynchronization) and a subsequent increase (event-related synchronization) that is thought to reflect cortical activation and the inhibitory/recovery process, respectively. These oscillatory changes are also believed to be affected by the status of the basal ganglia and by dopaminergic functions. In the present study, we investigated the association between the NS personality trait and somatosensory oscillatory changes after median nerve stimulation assessed by magnetoencephalography. Methods: From 48 healthy subjects, we selected 14 high scorers and 14 age- and sex-matched low scorers on the NS dimension of the Temperament and Character Inventory. Magnetic fields were recorded while subjects received electrical stimulation of either the right or left median nerve with equal probability and with a randomized interstimulus interval. Frequency analysis was performed on the alpha and beta bands. Results: Compared with the low NS group, the high NS group showed larger magnitude of beta event-related desynchronization and larger latencies of the alpha and beta event-related synchronization. Conclusion: These results suggest that individuals with high degrees of the NS trait have greater reactivity and delayed recovery of the sensorimotor cortex in response to simple somatosensory stimulation. This may be significant for the understanding of their exploratory and impulsive behavior.

Brain Structural Correlates of Reward Sensitivity and Impulsivity in Adolescents with Normal and Excess Weight

“…This area occupies the most lateral aspect of SII, adjacent to the representation of the oral cavity within the primary somatosensory cortex, and thus it is mainly involved in the processing of somatosensory information, including the sensory input relevant for gustatory awareness [29], [30]. Interestingly, somatosensory processing regions have been associated with reward sensitivity in healthy individuals with high scores in this personality trait [31]. Moreover, somatosensory regions consistently show increased activations towards food cues in both adolescents at risk of developing obesity [10] and in obese adolescents [10].…”

Sex differences in sensorimotor mu rhythms during selective attentional processing

“…These changes can be observed bilaterally but are typically stronger in the contralateral hemisphere (Devos et al, 2006;Nikouline et al, 2000;. Various experiments involving somatosensory processing and motor performance have described task-related ERD, followed by an increase in power above baseline levels (event-related synchrony; ERS) (Shishida, Hashizume, Onoda, Okamoto, Yamawaki, 2006;Toro et al, 1994). This well documented event-related patterning suggests that somatosensory events (whether evoked or voluntary) provoke early activation in SI areas indicative of rapid processing of the sensory stimuli (Pfurtscheller, 2001), while execution of the movement causes bilateral deactivation in (or alternatively, a resetting of) sensorimotor areas (Huttunen, Komssi, & Lauronen, 2006;Lin & Forss, 2002;Sutherland & Tang, 2006).…”