Early Somatosensory Processing Over Time in Individuals at Risk to Develop Psychosis

Of Orchids and Dandelions: Empathy but Not Sensory Processing Sensitivity Is Associated with Tactile Discrimination Abilities

Many concepts of the human personality are based on assumptions about underlying physiological processes. The most prominent example is probably the concept of extraversion introduced by H.J. Eysenck decades ago. However, more recent approaches also propose that personality traits may be reflected by physiological processes. For example, empathic personality dimensions have been linked to tactile perception, suggesting that individuals with higher tactile sensitivity are also more empathetic to the sensations of others. Another recent example is the concept of sensory processing sensitivity, which has been linked to enhanced primary sensory processing. However, the exact relationship between tactile abilities and personality is still unclear, thus the current study aims to test whether different personality dimensions affect the performance in a tactile acuity task. Tactile abilities of healthy participants were tested with tactile 2-point-thresholds on the hands. Personality dimensions were examined with respect to empathy, sensory processing sensitivity, and the Big Five. Results revealed that empathy, but not sensory processing sensitivity, was associated with tactile performance. We conclude that the ability to feel with someone else seems to be linked to the perception of our own body. Thus, the sense of touch may play an important role for empathy. We discuss explanations of these results and highlight possible implications of our findings.

Evidence for prefrontal cortex hypofunctioning in schizophrenia through somatosensory evoked potentials

Patients with schizophrenia (SCZ) exhibit a variety of symptoms related to altered processing of somatosensory information. Little is known, however, about the neural substrates underlying somatosensory impairments in SCZ. This study endeavored to evaluate somatosensory processing in patients with SCZ compared to healthy individuals by generating somatosensory evoked potentials through stimulation of the right median nerve. The median nerve was stimulated by a peripheral nerve stimulator in 34 SCZ and 33 healthy control (HC) participants. The peripheral nerve stimulus (PNS) intensity was adjusted to 300 percent of sensory threshold and delivered at 0.1 Hz. The EEG data were acquired through 64-channels per 10-20 montage. We collected and averaged 100 trials and the recording electrodes of interest were the F3/F5 electrodes representing the dorsolateral prefrontal cortex (DLPFC) and C3/CP3 representing the somatosensory cortex (S1). In response to PNS, SCZ participants experienced over the DLPFC N30 amplitude that was significantly smaller than that of HC participants. By contrast, S1 N20 was of similar amplitude between the two groups. In addition, we found an association between N20 and N30 amplitudes in SCZ but not in HC participants. Our findings suggest that patients with SCZ demonstrate aberrant processing of somatosensory activation by the DLPFC locally and not due to a connectivity disruption between S1 and DLPFC. These results could help to develop a model through which to DLPFC hypofunctioning could be studied. Our findings may also help to identify a potential biological target to treat somatosensory information processing related deficits in SCZ.