Corpus striatum
Corpus striatum
• consists of the caudate nucleus and the
lentiform nucleus. Lentiform nucleus can
be divided into putamen and the globus
pallidus.
• Basal Ganglia:
– Corpus striatum, claustrum, and amygdaloid
body are generally referred as
• Lentiform nucleus
– Shape and size of a nut, Globus pallidus is medial to putamen
• Lentiform is separated from insula by a thin layer of
white matter called external capsule, followed by a thin
sheet of gray matter called claustrum.
• Extreme capsule
– separates claustrum and insula
• The medial surface of the lentiform lies against internal
capsule.
• Caudate nucleus
– anterior head then tapers into slender tail extending backwards
and then forward
Connections
• Afferent fibers
• Striatum receives fibers from the cerebral cortex, thalamus,
and substania nigra.
• 1). Corticostriate fibers
originate from cortex excitory fibers, (including four lobes
especially frontal and parietal), fibers from of
somatosensory and motor area project to putamen; fibers
from cingulate gyrus and temporal (including
parahippocampal gyrus) cortex project to ventral striatum;
Other cortical areas project to caudate nucleus.
• Most of these fibers enter the striatum from internal
capsule, some enter putamen from external capsule.
Caudate striatum also receives fibers from amygdala (more
later)
Connections
• 2). Thalamostriate fibers
originate from intralaminar nuclei of
thalamus
• 3) nigrostriate fibers
originate from substantia nigra. In people
with Parkinson's disease, this area is
lacking dopamine.
Fig 12-4
Afferent fibers are blue
Efferent fibers are red
Efferent fibers
• 1). striopallidal fibers:
– to globus pallidus, control globus pallidus
• 2). strionigral fibers:
– pass through globus pallidus first then enter
pars reticulata and pars compacta of the
substantia nigra
Pallidum
• Afferent fibers:
– Striopallidal fibers
principal afferent fibers to pallidum, inhibitory
• Efferent fibers (pallidothalamic tract - two
components)
– originate from globus pallidus, cross the internal
capsule and form the lenticular fasciculus
– others form ansa lenticularis
• Both tracts terminate into nuclei in thalamus.
Fig 12-4
Afferent fibers are blue
Efferent fibers are red
Functions
• Functional aspect of basal ganglia
corpus striatum may be responsible for
memory of movement
• Lesion of basal ganglia does not cause
paralysis, but causes unwanted
involuntary movements.
Diseases
• Huntington's Disease
• Dominant hereditary with onset in middle
life, atrophy of striatum, choreiform
movements (multiple muscles, brisk, jerky
purposeless movements), concurrent
deterioration of mental capacity caused by
loss of neurons in cerebral cortex.