BASAL GANGLIA

1. DR S.KRITHIKA MDDr I.GURUBHARATH MD PhD

2. INTRODUCTION
 The basal ganglia comprise several deep grey matter
nuclei within the forebrain, midbrain and
diencephalon
Caudate nucleus
Putamen
Globus pallidus (also referred to as the pallidum)
Subthalamic nucleus
Substantia nigra.
CORPUS
STRIATUM

3. CAUDATE NUCLEUS
 Head,body and tail.
 The head of the caudate nucleus indents the horn of
the lateral ventricle.
 Its body curves upwards and posteriorly from the
head, following the contour of the body of the lateral
ventricle.
 The tail, which comes to lie immediately superior to
the temporal horn of the lateral ventricle

9. LENTIFORM NUCLEUS
This is shaped like a biconcave lens.
 It is made up of a larger lateral putamen and a smaller
medial globus pallidus
Medially, it is separated from the head of the caudate
nucleus anteriorly, and from the thalamus posteriorly
by the internal capsule.
 A thin layer of white matter on its lateral surface is
called the external capsule

11.  The subthalamic nucleus is an ovoid aggregation of
greymatter that lies medial to the internal capsule,
lateral to the hypothalamus and superolateral to the
red nucleus.
 It establishes connections with both internal and
external segments of the globus pallidus and with the
thalamus.
 Damage to this nucleus results in contralateral
hemiballismus –uncontrolled jerks of the limbs

14.  Strands of grey matter connect the head of the caudate
nucleus with the putamen of the lentiform nucleus across
the anterior limb of the internal capsule The resulting
striated appearance gives rise to the term corpus striatum
CLAUSTRUM
 This thin sheet of grey matter lies between the putamen
and the insula
 It is separated medially from the putamen by the external
capsule and bounded laterally by a thin sheet of white
matter (the extreme capsule) just deep to the insula The
claustrum is cortical in origin but its function is unknown

15. FUNCTIONS
 The function of the corpus striatum is not well understood
It is part of the extrapyramidal system and influences
voluntary motor activity.
 Cortical afferents enter the putamen and caudate nucleus,
which send efferents to the globus pallidus This in turn
sends efferents to the hypothalamus, brainstem and spinal
cord
 Control of movements
 Role in motivation
 Decision making
 Working memory

16.  Age related calcium deposition in globus pallidus
initially results in increased T1 signal intensity and
when subsequently when calcification exceeds 40%
there is signal loss in all sequences.
 Ageing with consequent iron deposition in putamen
results in gradual decrease of T2/SWI signal intensity
 More seen in 8th and 9th decade

17. TAKE HOME POINTS
 Corpus striatum is composed of caudate nucleus and
putamen,Putamen and globus pallidus is known as
lentiform nucleus.
 The caudothalamic groove between the head of the
caudate and the thalamus on the floor of the lateral
ventricle is the commonest site of haemorrhage in
preterm infants.
 Age related basal ganglia(GP) calcification is common
 MRI is sensitive to paramagnetic substances such as
iron,giving different signal intensities.

18. THANKYOU