The sense of touch is critical to the normal life of people.
However, the process of how information from the outside world is transmitted to the cerebral cortex and then translated into the sense of touch is not well understood.
Recently, two studies published in Cell and Nature have revealed the role of the human spinal cord and brainstem in tactile perception.
In one of the studies, the researchers used a new technique to record the activity of multiple spinal cord neurons while giving mice multiple tactile stimuli.
They found that more than 90% of the sensory neurons in the dorsal horn region of the mouse spinal cord responded to light touch stimuli.
These neurons did not have the same response pattern and were able to work together to form a complex neural network that was eventually transmitted to the brainstem by postsynaptic dorsal column (PSDC) neurons.
When some dorsal horn neurons are silenced, the richness of information transmitted to the brainstem is reduced.
In another study, researchers alternately silenced the direct pathway, which transmits information from mouse skin receptors into the brainstem, and the indirect pathway, which transmits from the spinal cord, and recorded brainstem activity.
The study found that the direct pathway contained mainly high-frequency vibratory stimuli, while the indirect pathway transmitted pressure stimuli.
Together, the two studies revealed the transmission pathways of nociceptive stimuli, the diversity of neurons involved, and the complexity of the neural network.
