L3 Flashcards
Myencephalon overview
Hb r4-8; (d-v)- cranial NC, ganglionic PaSNS, chloroid plexus, medullary nuclei, SMNs, BMNs, VMNs
Caudal myencephalon
DCN- first order SSNs synapse here, second order relay to thalamus, send axons out ventrally across midline to medial lemniscus; Medial lemniscus- tract containing DCN axons from medulla to thalamus; Pyramidal decussation- where medulla meets SC, corticospinal axons cross midline to contralateral side
(3 caudal Raphe nuclei)
Mid Myelencephalon
Vestibular nucleus- vestibular SNs arrive in vestibulocochlear N, primary nucleus for balance; Gustatory nucleus- input from front region of solitary nucleus (gustatory tongue Ns); Solitary nucleus- input from VSNs as part of autonomic homeostasis, tract in middle carrying axons bidirectionally (+medullary pyramid)
Rostral myelencephalon
Cochlear nuclei- auditory SNs arriving in vestibulocochlear N, primary nucleus for sound, axons to superior olive; Superior olive- receives input from cochlear nuclei in both sides of brain stem (L vs R for spatial sound processing); Inferior olive- sensory Rs in muscles-climbing fibres-> cerebellum, allows cerebellum to fine tune movement; (medullary pyramid)
(2 rostral Raphe nuclei)
Metencephalon overview
Hb r1-3, (d-v)- cranial neural crest, ganglionic PaSNS, cerebellum, pons, SMNs, BMNs, VMNs
Metencephalon detail
Cerebellum- cortical region that refines motor control output (intended vs actual), in from PMC via pontine nuclei,from muscle via inferior olive; Deep cerebellar nuclei- carry cerebellar output to other brain regions; Pontine nuclei- info about intended movement to cerebellum, PMC to ipsilateral pontine nuclei via corticopontine tract, pontine nuclei to contralateral cerebellum via pontocerebellar tract (pontine terminal = mossy fibres); Pontine reticular formation- sleep/wake nuclei, Raphe nuclei; Rostral pons contains LC- major NAdergic area- pain, panic, stress
Mesencephalon
Pretectum
Tectum- superior colliculus (visual relay from RGC); inferior colliculus (auditory relay from cochlear nuclei)
Tegmentum- PAG (major pain centre, descending via dorsal horn); MRF (basic functions, 2 pairs of Raphe nuclei); SN (nigrostriatal to St ((PD); VTA (to PFC via mesocortical, to NAc via mesolimbic (schiz))
