Ansa lenticularis - Mashpedia Real-time Encyclopedia

Brain: Ansa lenticularis

The image shows dopaminergic pathways of the human brain in normal condition (left) and Parkinsons Disease (right). Red Arrows indicate suppression of the target, blue arrows indicate stimulation of target structure. (Ansa lenticularis visible but not labeled, as red line from GPi to THA.)
Latin	Ansa lentiformis
Gray's	subject #189 837
NeuroNames	hier-427

The ansa lenticularis (ansa lentiformis in older texts) is a part of the brain, making up the superior layer of the substantia innominata of Meynert. Its fibers, derived from the medullary lamina of the lentiform nucleus, pass medially to end in the thalamus and subthalamic region, while others are said to end in the tegmentum and red nucleus.

It is classified by NeuroNames as part of the subthalamus.

References [edit]

This article incorporates text from a public domain edition of Gray's Anatomy.

External links [edit]

MedEd at Loyola Neuro/nlDEs/nl04s.html

Human brain: diencephalon (TA A14.1.08, GA 9.807)

Epithalamus

Surface	Pineal body Habenula Habenular trigone Habenular commissure

Grey matter	Pretectal area Habenular nuclei Subcommissural organ

Thalamus

Surface	Stria medullaris of thalamus Thalamic reticular nucleus Taenia thalami

Grey matter/ nuclei	paired: AN Ventral VA/VL VP/VPM/VPL Lateral LD LP Pulvinar nuclei Metathalamus MG LG midline: MD Intralaminar Centromedian Midline nuclear group Interthalamic adhesion

White matter	Mammillothalamic fasciculus Pallidothalamic tracts Ansa lenticularis Lenticular fasciculus Thalamic fasciculus PCML Medial lemniscus Trigeminal lemniscus Spinothalamic tract Lateral lemniscus Dentatothalamic tract Acoustic radiation Optic radiation Subthalamic fasciculus Anterior trigeminothalamic tract Medullary laminae

Hypothalamus

Surface

Grey matter

Autonomic zones	Anterior (parasympathetic/heat loss) Posterior (sympathetic/heat conservation)

Endocrine	posterior pituitary: Paraventricular magnocellular parvocellular Supraoptic oxytocin/vasopressin other: Arcuate (dopamine/GHRH) Preoptic (GnRH) Suprachiasmatic (melatonin)

Emotion	Lateral Ventromedial Dorsomedial

White matter

afferent
- SN → Medial forebrain bundle
efferent
- Mammillothalamic fasciculus → AN, Stria terminalis → Amygdala, Dorsal longitudinal fasciculus → SC

Pituitary

Posterior is diencephalon, but anterior is glandular

Subthalamus

Ventricular system:
Third ventricle

recesses:

Subfornical organ

Apertures: Interventricular/Monro

Posterior commissure

M: CNS

anat (n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp

noco (m/d/e/h/v/s)/cong/tumr, sysi/epon, injr

proc, drug (N1A/2AB/C/3/4/7A/B/C/D)

Human brain, cerebrum, Interior of the cerebral hemispheres—Rostral Basal ganglia and associated structures (TA A14.1.09.321–552, GA 9.832–837)

Basal ganglia

Grey matter

Corpus striatum	striatum: Putamen Caudate nucleus lentiform nucleus: Putamen Globus pallidus (GPe GPi)

Ventral striatum	Nucleus accumbens Olfactory tubercle Islands of Calleja

Other	Amygdala Claustrum

White matter

Semioval center

Internal capsule (Anterior limb

Corona radiata

Pallidothalamic tracts: Thalamic fasciculus (Ansa lenticularis

Rhinencephalon

Grey matter	Anterior olfactory nucleus Anterior perforated substance Olfactory bulb

White matter	Olfactory tract (Medial olfactory stria Lateral olfactory stria) Olfactory trigone

Other basal forebrain

Grey matter	Substantia innominata (Basal optic nucleus of Meynert) Nucleus of diagonal band

White matter	Diagonal band of Broca Stria terminalis

Archicortex:
Hippocampal formation/
Hippocampus anatomy

Grey matter	Hippocampus proper: CA1 CA2 CA3 CA4 Dentate gyrus: Fascia dentata Subiculum

White matter	Alveus Fimbria Perforant path Schaffer collateral

M: CNS

anat (n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp

noco (m/d/e/h/v/s)/cong/tumr, sysi/epon, injr

proc, drug (N1A/2AB/C/3/4/7A/B/C/D)

Brain and spinal cord: neural tracts and fasciculi

Sensory/
ascending

PCML

1°: Pacinian corpuscle/Meissner's corpuscle → Posterior column (Gracile fasciculus/Cuneate fasciculus) → Gracile nucleus/Cuneate nucleus

2°: → sensory decussation/arcuate fibers (Posterior external arcuate fibers, Internal arcuate fibers) → Medial lemniscus/Trigeminal lemniscus → Thalamus (VPL, VPM)

3°: → Posterior limb of internal capsule → Postcentral gyrus

Anterolateral/
pain

Fast/lateral	1° (Free nerve ending → A delta fiber) → 2° (Anterior white commissure → Lateral and Anterior Spinothalamic tract → Spinal lemniscus → VPL of Thalamus) → 3° (Postcentral gyrus) → 4° (Posterior parietal cortex) 2° (Spinotectal tract → Superior colliculus of Midbrain tectum)

Slow/medial	1° (Group C nerve fiber → Spinoreticular tract → Reticular formation) → 2° (MD of Thalamus) → 3° (Cingulate cortex)

Motor/
descending

Pyramidal	flexion: Primary motor cortex → Posterior limb of internal capsule → Decussation of pyramids → Corticospinal tract (Lateral, Anterior) → Neuromuscular junction

Extrapyramidal	flexion: Primary motor cortex → Genu of internal capsule → Corticobulbar tract → Facial motor nucleus → Facial muscles flexion: Red nucleus → Rubrospinal tract extension: Vestibulocerebellum → Vestibular nuclei → Vestibulospinal tract extension: Vestibulocerebellum → Reticular formation → Reticulospinal tract Midbrain tectum → Tectospinal tract → muscles of neck

Basal ganglia	direct: 1° (Motor cortex → Striatum) → 2° (GPi) → 3° (Lenticular fasciculus/Ansa lenticularis → Thalamic fasciculus → VL of Thalamus) → 4° (Thalamocortical radiations → Supplementary motor area) → 5° (Motor cortex) indirect: 1° (Motor cortex → Striatum) → 2° (GPe) → 3° (Subthalamic fasciculus → Subthalamic nucleus) → 4° (Subthalamic fasciculus → GPi) → 5° (Lenticular fasciculus/Ansa lenticularis → Thalamic fasciculus → VL of Thalamus) → 6° (Thalamocortical radiations → Supplementary motor area) → 7° (Motor cortex) nigrostriatal pathway: Pars compacta → Striatum

Cerebellar

Afferent

Vestibular nucleus → Vestibulocerebellar tract → ICP → Cerebellum → Granule cell

Pontine nuclei → Pontocerebellar fibers → MCP → Deep cerebellar nuclei → Granule cell

Inferior olivary nucleus → Olivocerebellar tract → ICP → Hemisphere → Purkinje cell → Deep cerebellar nuclei

Efferent

Dentate nucleus in Lateral hemisphere/pontocerebellum → SCP → Dentatothalamic tract → Thalamus (VL) → Motor cortex

Interposed nucleus in Intermediate hemisphere/spinocerebellum → SCP → Reticular formation, or → Cerebellothalamic tract → Red nucleus → Thalamus (VL) → Motor cortex

Fastigial nucleus in Flocculonodular lobe/vestibulocerebellum → Vestibulocerebellar tract → Vestibular nucleus

Bidirectional:
Spinocerebellar

Unc. prop.	lower limb → 1° (muscle spindles → DRG) → 2° (Posterior thoracic nucleus → Dorsal/posterior spinocerebellar tract → ICP → Cerebellar vermis) upper limb → 1° (muscle spindles → DRG) → 2° (Accessory cuneate nucleus → Cuneocerebellar tract → ICP → Anterior lobe of cerebellum)

Reflex arc	lower limb → 1° (Golgi tendon organ) → 2° (Ventral/anterior spinocerebellar tract→ SCP → Cerebellar vermis) upper limb → 1° (Golgi tendon organ) → 2° (Rostral spinocerebellar tract → ICP → Cerebellum)

M: CNS

anat (n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp

noco (m/d/e/h/v/s)/cong/tumr, sysi/epon, injr

proc, drug (N1A/2AB/C/3/4/7A/B/C/D)

M: PNS

anat (h/r/t/c/b/l/s/a)/phys (r)/devp/prot/nttr/nttm/ntrp

noco/auto/cong/tumr, sysi/epon, injr

proc, drug (N1B)