reticular formation

200. Reticular formation -Mass of neurons and nerve fibers extending from the caudal medulla to the rostral midbrain -comprises a neural system with multiple inputs and multisynaptic system of impulse conduction -one of the oldest parts of the rbain

Functions : -regulating the sleep-wake cycle ,states of consciousness
-filtering incoming stimuli to discriminate irrelevant background stimuli (habitation)
-Somatic motor control ( 1. ) reticulospinal tracts maintain balance , tone 2.) relays visual,auditory stimuli to cerebellum so it can coordinate movements , 3)produce rhythmic signals to muscles of swallowing and breathing ) -Cardiovascular control – RF includes the cardiac andvasomotor centers of the medulla oblongata
-Pain modulation : -afferent fibers as well as descending analgesic pathways -Premotor cortex regulates posture via the reticular formation

-organized into definite nuclear groups with known afferent and efferent connections each group is represented at level of MO ,pons , midbrain groups : median raphe - & Paramedian/Medial /Lateral reticular nuclear group

Median raphe reticular nuclear group rostral raphe nuclei → reticular activatingsystem (wakefulness, alertness, and sleep) caudal raphe nuclei → pain mechanisms

medial reticular nuclear group ascending projections → consciousness and alertness descending projections→ motor control Paramedian reticular nuclei - in interaction with cortex and spinal cord it is involved in the control of movements due to interaction with the cerebellum

Lateral reticular nuclei
-connections with cortex & substantia nigra → locomotor center
-connections with amygdala, nucleus solitarius, hypothalamus → autonomic function
-receptive component of reticular nuclei – receive