Reticular Formation and Diffuse Modulatory System: Neuronal Networks and Neurotransmitters, Study Guides, Projects, Research of Neuroscience

Download Reticular Formation and Diffuse Modulatory System: Neuronal Networks and Neurotransmitters and more Study Guides, Projects, Research Neuroscience in PDF only on Docsity! 1 of 2 TeachSheet Reticular Formation & Diffuse modulatory system Overview of the Reticular Formation (RF)  The term reticular formation refers to the neuronal network within the brainstem, although it continues rostrally into the thalamus and hypothalamus and caudally into the propriospinal network of the spinal cord.  A “coordinating system” (like the Limbic system) with “connections” to sensory, somatic motor and visceral motor systems  Organization can be subdivided into two neuronal cell “columns” (medial to lateral) as well as on the basis of their neurotransmitter release Neuronal columns (many nuclei and names, but these are some of the major ones): o “Medial tegmental field” (large-celled nuclei)  Origin of the reticulospinal pathway  Role in coordinating posture, eye and head movements. o “Lateral tegmental field” (smaller and fewer cells, shorter local projections)  Extends from the medulla to the pons  Coordinate autonomic and limbic functions (e.g. micturition, swallowing, mastication and vocalization)  The functions of the reticular formation include their ability to coordinate motor and sensory brainstem nuclei: o Pattern generator  Eye movements; horizontal (PPRF) and vertical (riMLF)  Rhythmical chewing movements (pons)  Posture and locomotion (midbrain and pons)  Swallowing, vomiting, coughing and sneezing (medulla)  Micturition (pons) o Respiratory control (medulla); expiratory, inspiratory, apneustic and pneumotaxic o Cardiovascular control (medulla); vasomotor pressor/depressor, cardioacceleratory and inhibitory.  Afferents arise from baroreceptors (carotid sinus and aortic arch), chemoreceptors (carotid sinus, lateral reticular formation chemosensitive area in the medulla) and stretch receptors (lung and respiratory muscles)  Efferents arise from reticular formation neurons within the pons and medulla o Sensory modulation or “gate” control  The term “gating” refers to “modulation” of synaptic transmission from one set of neurons to the next. Neuroanatomical “Roadmaps and sites” within the Reticular Formation Afferents mainly to the medial portion of the RF (esp. the Gigantocellular, Caudal and PPRF)  Spinoreticular o Collateral fibers of the spinothalamic tract, widespread bilateral distribution, but without somatotopy  Trigeminal, vestibular, auditory and visceral o Project to the parvocellular zone (vestibular fibers also to the PPRF)  Cerebelloreticular o Project to the paramedian reticular nuclei; primarily originate from the fastigial nucleus  Tectoreticular o From the superior colliculus’ deeper layers  Corticoreticular o Originate in motor and premotor cortex and targeted towards the cells of origin of the reticulospinal tracts (provides a mechanism of cortical feedback)