o Caudate nucleus
BASAL NUCLEI (GANGLIA) o Lentiform nucleus
Role: Control posture and voluntary “striatum”
movement. o Striated appearance
produced by strands of gray
- Has no direct input or output
matter passing through the
connections with spinal cord.
internal capsule and
connecting the caudate
nucleus to the putamen of
TERMINOLOGY
the lentiform nucleus.
Basal Nuclei – collection of masses of gray
matter situated within each cerebral
hemisphere.
- Corpus striatum
- Amygdaloid nucleus
- Claustrum
Structures closely related in function that
are not included in the term:
- Subthalmic nuclei
- Substantia nigra
- Red nucleus
Caudate Nucleus – large C-shaped mass of
gray matter.
closely related to the lateral
ventricle
Lies lat. to thalamus
Lat. surface of the nucleus is related
to internal capsule which separates
it from the lentiform nucleus.
Can be divided into head, body, and
tail.
Head – large and rounded, forms the
CORPUS STRIATUM
lat. wall of the ant. horn of the lat.
Situated lateral to the thalamus ventricle.
Almost completely divided by a band o Continuous inf. c the
of fibers: putamen of the lentiform
o Internal capsule nucelus
Body – long and narrow. o Putamen – larger, darker lat.
o Continuous c the head in the portion
region of the interventricular Putamen is
foramen. continuous c the head
o Forms the floor of the body of the caudate
of the lat. ventricle. nucleus.
Tail – long and slender. o Globus pallidus – inner
o Continuous c the body in the lighter portion
region of the post. end of the Paleness d/t presence
thalamus of high concentration
o Follows the contour of the of myelinated fibers
lat. ventricle
o Continues forward to the
roof of the inferior horn of
the lat. ventricle.
o Terminates anteriorly in the
amygdaloid nucleus.
Lentiform Nucleus – wedge-shaped mass of
gray matter.
Broad convex base – directed
laterally
Blade – directed medially
Buried deep in the white matter of
cerebral hemisphere.
Relations:
o Medially – internal capsule AMYGDALOID NUCLEUS
o Laterally – external capsule
Separates it from Situated in the temporal lobe close
claustrum (thin sheet to the uncus.
of gray matter) Considered part of limbic system.
o Claustrum – separates Through connections, it can
external capsule from influence:
subcortical white matter of o Body’s response to
the insula. environmental changes /
Vertical plate of white matter external stimuli.
divides nucleus into larger, darker HR
lat. portions and an inner lighter BP
portion: Skin color
RR
SUBSTANTIA NIGRA AND SUBTHALAMIC Thalamostriate fibers
NUCLEI o Intralaminar nuclei of
thalamus caudate nucleus
Substantia nigra – midbrain
et. Putamen.
o Neurons – dopaminergic
Nigrostriatal fibers
o Inhibitory
o Substantia nigra caudate
o Has connections to corpus
nucleus and putamen
striatum
o Neurotransmitter: dopamine
Subthalamic nuclei – diencephalon
(inhibitory)
o Neurons – glutaminergic
Brainstem Striatal Fiberes
o Excitatory
o Ascending fibers from
o Has many connections to the
brainstem caudate
globus pallidus and
nucleus and putamen
substantia nigra
o Neurotransmitter: serotonin
CLAUSTRUM (inhibitory)
Thin sheet of gray matter separated Corpus Striatum Efferent Fibers
from the lateral surface of the
Striatopallidal fibers
lentiform nucleus by the external
o Corpus striatum globus
capsule.
pallidus
Lateral – subcortical hite matter of
o Neurotransmitter: y-
the insula
aminobutyric acid (GABA)
Function – unknown
Striatonigral fibers
CONNECTIONS OF THE CORPUS STRIATUM o Corpus striatum
AND GLOBUS PALLIDUS substantia nigra
o Neurotransmitter:
Caudate nucleus and putamen –
GABA
form main sites for receiving input
Acetylcholine
from basal nuclei.
Substance P.
Globus pallidus – major site from
which the output leaves the basal Globus Pallidus Afferent Fibers
nuclei
Striatopallidal fibers – GABA
These structures receive no direct
input/output from spinal cord. Globus pallidus efferent fibers
Corpus striatum afferent fibers: Pallidofugal fibers (4 groups)
o Ansa lenticularis – thalamic
Corticostriate fibers
nuclei
o Cortex caudate-putamen
o Fasciculus lenticularis –
complex
subthalamus
o Neurotransmitter: glutamate
o Pallidotegmental – caudal BASAL NUCLEI FUNCTIONS
tegmentum midbrain
Joined together and connected c
o Pallidosubthalamic fibers –
many different regions of the
subthalamic nuclei
nervous by complex number of
neurons.
1. Corpus striatum receives afferent
information from cerebral cortex,
thalamus, subthalamus, brainstem,
substantia nigra.
2. Information is integrated within
corpus striatum
3. Outflow passes back to areas in (1)
Activity of basal nuclei – initiated by
information received from premotor
and supplemental areas of the
motor cortex, sensory cortex,
thalamus, brainstem.
Outflow channeled through globus
pallidus
o Influences activities of the
motor areas of cerebral
cortex
Basal nuclei – control mm.
movements without direct control
through descending pathways to
brainstem and spinal cord.
o Assist in regulation of
voluntary mvmt and learning
of motor skills (mm.
memory).
o Also helps prepare for
movements
