Neuroscience: Brainstem Nuclei

Front 1

Red Nucleus

Back 1

In midbrain
-Motor Nucleus of the rubrospinal tract (crosses midline at VTD, projects to interneurons in V-VIII)
-participates in a circuit linking the inferior olive and cerebellum

Front 2

Substantia Nigra

Back 2

-midbrain, uses dopamine
-receives input from the putamen and caudate nuclei of the basal ganglia and sends fibers back
-sends fibers to thalamus

Front 3

Superior Colliculus

Back 3

-midbrain
-receives input from Optic N.
-Origin of tectospinal tract which controls posture and head movements in response to visual stimuli. Crosses midline at MTD, projects bilaterally to motor neurons in s.c.
-controls visual reflexes

Front 4

Inferior Colliculus

Back 4

-midbrain
-major auditory nucleus
-sends fibers to MGB medial geniculate body (thalamus)
-receives input from the superior olivary nucleus through the lateral lemniscus

Front 5

Pontine Nuclei

Back 5

-pons
-receives input from cerebral cortex through cerebral peduncle
-output to contralateral cerebellar hemisphere through middle cerebellar peduncle

Front 6

Superior Olivary Nucleus

Back 6

-pons
-forms lateral lemniscus
-in auditory pathway between cochlear nuclei and inferior colliculus

Front 7

Inferior Olivary Nucleus

Back 7

-medulla
-input from red nucleus, s.c.
-fibers cross midline to enter cerebellum through inferior cerebellar peduncle

Front 8

Nucleus of the Solitary Tract (Solitary nucleus)

Back 8

-medulla
-inputs: taste from VII, IX, X
-outputs: taste to thalamus, visceral reflex to Dorsal Motor nucleus of X, reticular formation

Front 9

Spinal Accessory nucleus

Back 9

-rostral cervical s.c. (C1-C6)
-innervates trapezius and SCM
-fibers ascend to join with fibers of X and IX thru foramen magnum

Front 10

Dorsal Column Nuclei

Back 10

-medulla
-Nucleus Gracilis (leg, medial), Nucleus Cuneatus (arm, lateral)
-Receives fine touch/discriminatory sensation/pressure from spinal cord
-crosses midline as internal arcuate fibers, ascends as medial lemniscus
-projects to VPL nucleus of thalamus

Front 11

Accessory Cuneate Nuclei

Back 11

-medulla
-receives individual muscle sense from above C8 from dorsal spinocerebellar tract (DRG)
-projects to cerebellum through inferior cerebellar peduncle

Front 12

Median and Dorsal Raphe Nuclei

Back 12

-midbrain and pons
-serotonergic
-modulates pain transmission at spinal cord level
-sends fibers to forebrain, cerebellum for arousal and learning

Front 13

Nuelcus Pontis Oralis/Caudalis, Gigantocellular Reticular Nucleus

Back 13

-pons, medulla (GRN)
-Forms medial and latereal reticulospinal pathways
-regulates muscle tone, reflex, and postural mechanisms

Front 14

Pedunculopontine Tegmental Nucleus/Laterodorsal Tegmental Nucleus/Parabrachial Nucleus

Back 14

-pons
-projects to intralaminar nucleus of thalamus, then to cortex where it regulates arousal/REM sleep and learning

Front 15

Locus Coeruleus

Back 15

-projects norepinephrine to forebrain to modulate forebrain function, attentional processes
-also projects NE to s.c. to regulate cerebellar and spinal cord excitability during sleep/wake cycle