Anatomy Flashcards
Secondary somatosensory and input
Superior bank of lateral sulcus
Input from IL VPLc and VPM, bilateral primary somatosensory (S1)
Output to IL S1 and primary motor
Homunculus is inverted
Brodmann primary somatosensory including input
Post central gyrus (3, 1, 2)
3a: muscle spindles
3b: cutaneous (skin)
1: muscle spindles and skin
2: deep joint receptors
Receptors -> medial lemniscus/spine thalamus tract -> VPLc/VPM -> 312
Face and tongue are bilateral
Primary visual cortex (V1)
Area 17, calcarine cortex
Input: LGB -> geniculocalcarine fibers along lateral ventricles (external Sagittal striatum) -> calcarine sulcus
Output: internal sagittal striatum -> corticofugal fibers -> superior colliculus and LGB
Macula goes to posterior 1/3 (occ pole)
Band of Baillarger in striate cortex is stripe of gennari visible to naked eye (layer IVb)
Secondary visual cortex (V2 and V3)
Area 18 and 19 (surrounds V1)
Input LGB and pulvinar
Lesion causes visual agnosia
Primary auditory cortex
Area 41 (heschl gyrus, on superior temporal gyrus in the temporal operculum) with association cortex area 42 surrounding it
Input: IL MGB (fibers pass through sublenticular ICA). Each cochlea goes BL but more CL then ILL
Ventral MGB: higher frequencies more medial
Trapezoid body in the pons is only auditory commissure needed for sound localization
Lesion: CL>IL partial deafness
Dominant Area 22 lesion: word deafness or sensory aphasia with normal hearing
Gustatory cortex
Area 43 (post central operculum next to tongue sensory area) Input: IL nucleus solitarius-> VPMpc -> 43
Vestibular cortex
Inferior parietal lobule near head part of S1
BL representation but slightly more CL
Primary motor cortex
Brodman 4, precentral gyrus; pyramidal cells of Betz (cortical layer 5)
Output to corticobulbar and corticospinal (BL to eye face and tongue); asp and glu
Input from IL VL and VLo, CL cerebellum, S1 (except area 3), supplemental motor cortex
Premotor cortex
Area 6a, anterior to motor cortex
Input from medial GP-> IL VApc, VLo, CM -> premotor
Motor control for responses dependent on sensory input
No deficit with UL lesion
Supplemental motor cortex (M2)
Area 6a, medial aspect anterior to M1, medial superior frontal gyrus
Output from IL 4, 5, 6, 7 and CL M2, b/l SC, caudate, put amen and thalamus
Input- bilateral
Lesion: HP or plegia, diminished spontaneous speech, may have volition all movt with effort
Frontal eye fields
Area 8, rostral to premotor in caudal middle frontal gyrus
Initiates saccades, stim causes CL eye deviation (IL controlled by area 17, occ eye center)
Output to rostral interstitial nucleus of MLF, interstitial nucleus of cajal, para median pontine reticular formation, superior colliculus
Does not go directly to cn 3, 4, 6
Lesion: impaired saccades esp if dominant hemisphere
Thalamus: anterior nuclear group
Regulates visceral function
Input: mamillothalamic tract, fornix
Output: cingulate gyrus via ant limb IC
Thalamus: mediodorsal group
Bren IML and periventricular grey
Integrates somatic and visceral activity, controls affective behavior, disconnected during prefrontal lobotomies
Input: amygdala, orbits frontal and temporal cortex
Output: frontal association cortex or prefrontal area
Reciprocal connections with frontal eye fields
Lesion: korsakoff psychosis
Thalamus: centromere all nucleus
Attention and arousal
Within IML
Input: area 4
Output: putamen, STN
Thalamus: Parafascicular Nuclei
Enclosed by IML
Arousal and wakefulness
Input: Area 6
Output: caudate
Thalamus: Rostral intralaminar nuclei
Enclosed by IML
Arousal and wakefulness
Input: RAS
Output: diffuse cortex
Thalamus: periventricular gray and massa intermedia
Output: amygdala and cingulate gyrus
In midline
Thalamus: lateral dorsal nuclei
Output: Cingular and supralimbic parietal lobe
Input: limbic areal
Thalamus: lateral posterior nucleus
Input: parietal lobe
Output: areas 5 and 7
Thalamus: pulvinar nucleus
Visual connections
Input: superior colliculus, reciprocal connections with occipital cortex, temporal and parietal loves
Output: inferior pulvinar to area 18, lateral pulvinar to area 19, medial pulvinar to superior temporal gyrus
Thalamus: ventral anterior nucleus
Recruits cortical response, programming of movements from BG, includes mamillothalamic tract
Input: GP, SN, area 6 and 8
Output: frontal cortex, intralaminar nuclei
Thalamus: ventral lateral pars oralis
Input: GP
Output: premotor and supplemental motor
Thalamus: ventrolateral pars caudalis
Input: CL deep cerebellar nuclei and red nucleus, reciprocal connections with area 4
Thalamus: ventroposterolateral pars oralis
Input: CL deep cerebellar nuclei
Output: motor cortex
Thalamus: ventroposterolateral pars caudalis
Input: medial lemniscus
Output: sensory cortex (limbs lateral, back dorsal)
Thalamus: ventroposteromedial
Input: CL spinal, principal sensory nuclei of CN 5, IL dorsal trigeminal tract
Output: sensory cortex to
-face: BL VPM
-taste: from NTS -> central regimental tract uncrossed to VPMpc -> parietal operculum area 43
Thalamus: ventral posterior inferior
Output: IL S2
Thalamus: Medial Geniculate Body
Auditory relay, located in caudal ventral thalamus
Input: inferior colliculus, reciprocal connections to primary auditory cortex (tonotopic, high frequencies are medial)
(heschl’s gyrus is in area 41, superior temporal convolution, where higher frequencies are still medial)
Thalamus: Lateral Geniculate Body
Visual relay, rostral and lateral to MGB, ventral to pulvinar
6 layers:
1-2: magnocellular
3-6: parvocellular
Input: retinal ganglion cells
-crossed fibers (CL eye) to 1,4,6
-uncrossed fibers (IL eye) to 2,3,5
Reciprocal connections with calcarine cortex (17), pulvinar
No Binocular fusion
Lower retina -> LGB -> Lower calcarine cortex
Thalamus: posterior
Input: spinothalamic tract, ML, S1
Output: retroinsular cortex, posterior auditory cortex
Thalamus: Reticular nuclei
Shell over dorsal thalamus, migrated derivative of ventral thalamus
Located between IC and EML
No cortical projections
Samples passing fibers, gates thalamus activity
Thalamus peduncles
Reciprocal connections between thalamus and cortex, within the IC
Anterior: medial and anterior thalamus to frontal lobe
Superior: sensorimotor to precentral and post central gyri
Posterior: visual to calcarine cortex
Inferior: auditory to Heschl’s gyri
Habenula
Smell, basic emotions that influence visceral responses, convergence of limbic pathways
Input: GP (to lateral habenulum), septal nuclei, lateral preoptic region and ant thalamic nuclei (all to medial habenulum), also lateral hypothalamus, substantia innominata, midbrain raphe nuclei, ventral tegmentum, superior cervical ganglia
Output: fascicles retroflexus (aka habenulointerpeduncular or Meynert’s fasciculus) -> interpeduncular nuclei and midbrain raphe nuclei -> reticular nuclei, hypothalamic nuclei and preganglionic nuclei
Pineal Gland
Attached to roof of third by ventral/posterior commissure and dorsal/habenular commissure
Made of glia and pinealocytes
Secretes: serotonin from pinealocytes, NE from terminating sympathetic neurons; TRH, LHRH, and somatostatin; melatonin (made from 5HT, max secretion in dark; over secretion delays puberty, under causes precocious puberty)
Inhibited by sympathetic innervation: light on retina -> suprachiasmatic nucleus of hypothalamus -> DLF -> upper intermediolateral cell column of superior colliculus -> inhibit pineal
BL lesion of hypothalamic suprachiasmatic nuclei abolishes circadian rhythms of eating and drinking, affects estrous cycle
Internal capsule: anterior limb
Prefrontal corticopontine tract and ant thalamic radiations
Blood supply from Ava (heubner caudal) and Mca (lenticulostriates lateral and rostral)
Internal capsule: genu
Corticobulbar and corticoreticular tracts
Blood supply: Mca lenticulostriates and Ica perforators
Internal capsule: posterior limb
Superior thalamic radiations, frontopontine tract, corticospinal/tectal/rubral/reticular tracts (motor is anterior to sensory, ctls rostral to caudal)
Blood supply: Mca lenticulostriates (lateral and rostral), anterior choroidal (caudal), pcomm (caudal)
Internal capsule: retrolenticular portion
Inferior thalamic radiations (auditory) and temporal and parietooccipital corticopontine fibers
Blood supply: anterior choroidal
Neostriatum/striatum
Caudate and putamen
Input:
-corticostriate: area 4 -> BL putamen; premotor -> IL caudate and putamen; prefrontal-> caudate
-amygdalostriate: lateral to caudate and putamen
-thalamostriate: CM to putamen, Parafascicular to caudate
-nigrostriatal: to caudate and putamen (inhib dopamine)
-raphe nucleus: inhib serotonin
Output:
- striatonigral: head of caudate to SNpr
- striatopallidal: caudate/putamen to GPi (inhib GABA)
- nigrothalamic: terminate in VA, VLm, MD (GABA)
Paleostriatum
Globus pallidus (medial and lateral, separated by medial medullary lamina), accessory medullary lamina divides MGP into inner and outer segments
Input:
-striatum: gaba and enkephalins to LGP; substance P to MGP
-STN: lateral -> reciprocal fibers (glu) to LGP; medial -> MGP
Output:
1. Ansa lenticularis (main): from MGP a, passed around IC -> Forel’s field H1 (FFH1)
2. Lenticular fasciculus (FFH2): from MGP a, passes through IC to join #1 in Forel’s field and enters thalamic fasciculus
3. Thalamic fasciculus (FFH1): made of ansa lenticularis, lenticular fasciculus, and cerebellothalamic tract (CL deep cerebellar nuclei) -> VA and VL
4. Pallidosubthalamic fibers: LGP to STN, MGP -> stria medullaris -> lateral habenulum, GP to VA/VL/CM
Also pallidotegmental fibers MGP a -> Forel H fibers -> pedunculopontine nucleus
Corpus striatum
Neostriatum and paleostriatum (caudate, putamen and GP)
Archistriatum
Amygdala
Lentiform nucleus
Putamen, GP
Diencephalon
Paleostriatum/GP and sub thalamic nucleus
Telencephalon
Neostriatum and archistriatum (caudate, putamen, amygdala)
Basal ganglia
Corpus striatum (caudate, putamen, GP,), amygdala, STN, SN
Caudate
Head- contiguous with anterior perforated substance
Body- separated from thalamus by stria terminalis and terminal vein
Tail- roof of temporal horn near amygdala
Nucleus accumbuns septi- where caudate and putamen meet anteriorly
Subthalamus
Posterolateral to hypothalamus, ventral to thalamus, medial to IC; lesions cause CL hemiballismus
Contains Subthalamic nuclei of Luys over rostral SN (lens shaped), zona incerta (grey matter between thalamic and lenticular fasciculi, continuous with thalamic reticular nucleus, input from motor cortex), sensory fasciculi (ML, spinothalamic and trigeminothalamic tract -> VP), cerebellar and GP fibers -> thalamus
Input: LGP, prefrontal, premotor, motor cortex, CM, PF, pedunculopontine nucleus
Output: LGP > MGP, SN
Glutamate
Claustrum
Input lateral hypothalamus, CM, locus ceruleus
Reciprocal connections with area 6
Substantia Nigra
Input: striatum -> SNpr, GP, STN, pedunculopontine nucleus, dorsal raphe nucleus
Output: SNpc-> striatum, SNpr -> thalamus, pedunculopontine
No output to GP
Corpus striatum
Output inhibitory to MGP and SNpr, inhibits thalamic output to premotor and supplemental motor but not to area 4
