The Varsity

A team of neuroscientists from the California Institute of Technology has discovered how the brain deciphers the emotional significance of touch.

The neural activity of heterosexual males was measured while they were being stroked on the leg as they watched two videos in succession. The first video featured an alluring woman leaning over to caress the participant’s body, and the second video showed a burly man performing the same action. Participants reported satisfaction when the caresser was believed to be female and repulsion when the caresser was believed to be male. Participants were actually stroked by a female experimenter in both conditions.

The experiment demonstrates that the same touch can elicit different responses in the cortex. In particular, a difference occurs when visual representations trigger presuppositions that distort the emotional interpretation of touch. Specifically, researchers discovered that the primary somatosensory cortex (S1), a region traditionally thought to be involved in encoding only simple, tactile properties, can also play a role in integrating sensory and emotional information.

The finding not only suggests a more complex function for the S1, but also challenges the traditional two-step perspective, which suggests that physical stimuli are processed prior to emotional stimuli. The experiment provides evidence that sensory modalities can be processed in parallel with physical ones.

The researchers hope to explore whether these results are generalizable to women, and children. The hope is that a deeper comprehension for these physical and emotional touch pathways will provide clinicians with the tools to help people with autism develop an understanding for the emotional component of touch, as well as help victims of physical abuse re-learn how to appreciate the affectionate caresses of their loved ones.

Source: Science Daily