Nucleus ventralis posterior
The nucleus ventralis posterior thalami ( VP ) (syn. Nucleus ventrocaudalis ) is a specific nucleus of the thalamus , part of the diencephalon . It is part of the system that conveys the sense of touch and the sense of pain ( somatosensory ).
The information that enters the nucleus is transmitted through various pathways that originate in the skin, joints and mucous membranes and then travel through the spinal cord and brain stem .
- The spinothalamic tract is the main channel for pain and temperature sensation from the trunk and extremities. The sense of touch and sensations via the joint position of the trunk and extremities ( proprioception ) are primarily guided via the lemniscus medialis . These two pathways end in the outer part of the posterior ventral nucleus. This part is therefore also called the nucleus ventralis posterolateralis (VPL) (syn. Nucleus ventrocaudalis externus ).
- The lemniscus trigeminalis transmits pain, temperature, touch and proprioception from the face (via the fifth cranial nerve, the trigeminal nerve ). This path ends in the middle part of the nucleus ventralis posterior. This part is therefore also called the nucleus ventralis posteromedialis (VPM) (syn. Nucleus ventrocaudalis internus ).
In essence, the incoming information is switched to new channels. These then pull as so-called upper thalamic stalk to the cerebral cortex , in particular to the cortical areas that are responsible for the conscious perception of pain, sense of touch and temperature ( gyrus postcentralis ). Paths that control the flow of information in the nucleus ventralis posterior descend from these cortical areas. This allows stimuli to be blocked or let through, which for example plays a role in the body's own pain inhibition.