Social Touch and Its Newly Discovered Neural Pathway - Neuroscience News

Summary: A neural pathway that leads directly from the thalamus to the hypothalamus plays a critical role in processing touch information, a new study reveals.

Touch plays an important role in social behavior.

The physical contact of touch is also important in social relations, just think of the grooming behavior of monkeys, or an appreciative pat on the back.

Neurobiologists have already identified that the information acquired through touch is relayed in the thalamus of ​​the brain and becomes conscious in the cerebral cortex, but at the same time, it has been suggested that the brain learns about the stimuli coming from our peers in another way, since the pleasant feeling appears even without awareness.

During their research, they pointed out that the neural pathway leading directly from the thalamus to the hypothalamus plays an important role in the processing of touch information, and this pathway uses the parathyroid hormone 2 neuropeptide (PTH2) as a neurotransmitter.

The hypothalamus, located in the lower part of the brain, under the thalamus, is the main regulatory center for the social behavior in rodents, because in this species the role of the cerebral cortex is not dominant.

However, it is not known how information necessary for social behavior arrives in the hypothalamus.

According to the hypothesis of the research, the ascending sensory pathway carrying information about social touch reaches the hypothalamus from the thalamus without relay in the cerebral cortex.

So this neural pathway plays an important role in the processing of information associated with contact.

This proved that the PTH2 peptide neurotransmitter transmits important social behavior-determining inputs to the preoptic area from the thalamus.

“This discovery may also be important in the future for treatment of psychological diseases, as the avoidance of physical contact is an inherent part of many diseases.

If we know these neural pathways and mechanisms, in the long term we can better understand why the avoidance of physical contact develops, and possibly prevent these processes and influence them favorably for the individual.

“A thalamo-preoptic pathway promotes social grooming in rodents” by Árpád Dobolyi.

A thalamo-preoptic pathway promotes social grooming in rodents.

Here, we discovered a novel neuronal pathway from the posterior intralaminar thalamic nucleus (PIL) to the medial preoptic area (MPOA) involved in the control of social grooming

The activity-dependent tagging of PIL neurons was performed in rats experiencing physical social contact

The chemogenetic activation of these neurons increased social grooming between familiar rats, as did the selective activation of the PIL-MPOA pathway

We propose that the discovered neuronal pathway facilitates physical contact with conspecifics