ANAT 321 Lecture Notes - Lecture 8: Thalamic Reticular Nucleus, Medial Geniculate Nucleus, Substantia Nigra
Document Summary
There is still a central structure of gray matter from the spinal cord running through the brainstem called the reticular formation: reticular = web-like. It has a high degree of complexity and organization. If stimulating electrodes are put into the reticular formation, the subject would become alert. The reticular neurons from the brainstem project up and synapse with intralaminar thalamic neurons in the thalamus. Norepinephrine neurons originate in the locus ceruleus and project to virtually the entire brain as well as the spinal cord: very discrete, very small regions in the brainstem. It is a neuromodulator of the brain - it works in a global aspect. Serotonin neurons originate in the brainstem raphe nuclei and project throughout the brain and spinal cord. The raphe nuclei run right through the midline of the reticular formation: also a small number of neurons, with very long axons. Dopamine neurons originate in the substantia nigra and the ventral tegmental area.