Search results
Results From The WOW.Com Content Network
The name dorsal-column medial lemniscus comes from the two structures that carry the sensory information: the dorsal columns of the spinal cord, and the medial lemniscus in the brainstem. There are three groupings of neurons that are involved in the pathway: first-order neurons, second-order neurons, and third-order neurons.
The dorsal column nuclei are responsible for fine touch, vibration, proprioception and two-point discrimination. The fibers of this decussation are called the internal arcuate fibers and are found at the superior aspect of the closed medulla oblongata, superior to the motor decussation. Neurons of these nuclei are second-order neurons in the ...
The cuneate and gracile nuclei reside at the closed (lower) medulla, so the medial lemniscus is not formed at this level. Fibres from these nuclei will pass to the contralateral side of the brainstem, as the internal arcuate fibres. In the midbrain, it is situated dorsal to the substantia nigra, and medial to either red nucleus. [4]
Upon decussation (crossing over) from one side of the medulla to the other, also known as the sensory decussation, they are then called the medial lemniscus. The internal arcuate fibers are part of the second-order neurons of the posterior column-medial lemniscus system , and are important for relaying the sensation of fine touch and ...
medial dorsal nucleus of thalamus nucleus raphe magnus and gigantocellular raphe nucleus → raphespinal tract → spinal trigeminal nucleus and posterior grey column of the spinal cord - the fibers of the tract terminate by forming excitatory serotonergic synapses with inhibitory enkephalinergic interneurons which in turn form inhibitory ...
The first-order neurons from the trigeminal ganglion enter the pons and synapse in the principal (chief sensory) nucleus or spinal trigeminal nucleus.Axons of the second-order neurons cross the midline and terminate in the ventral posteromedial nucleus of the contralateral thalamus (as opposed to the ventral posterolateral nucleus, as in the dorsal column medial lemniscus (DCML) system).
Both dorsal column nuclei contain synapses from afferent nerve fibers that have travelled in the spinal cord. [2] They then send on second-order neurons of the dorsal column–medial lemniscal pathway. Neurons of the dorsal column nuclei eventually reach the midbrain and the thalamus. [3] They send axons that form the internal arcuate fibers ...
From here, the signal travels through the dorsal column–medial lemniscus pathway. The pathway is composed of the dorsal column within the spinal cord and the medial lemniscus in the brain stem. [4] Collectively, the ascending sensory fibers are called the dorsal column because ascending fibers gather at the dorsal funiculus in the spinal cord ...