Lecture 10 -
Thalamus & Internal Capsule
Competencies:
- Break down the functional relationships of the sensory, motor and limbic thalamic nuclei.
- Draw the internal capsule and differentiate the sensory and motor radiations within it.
- Diagram the sources of blood supply to the internal capsule.
- Explain the role of lateral striate arteries, i.e.“the artery of cerebral hemorrhage”.
To master the material presented in this
lecture:
Read ...
Nolte text, Chapter 16.
Look at the Review Questions below ...
Listen to the lecture and focus on the
following points ...
Thalamus -
Thalamic nuclei are defined in relation to the
area of cortex with which they connect, and the function of each
is principally; sensory relay, or motor relay, or association relay,
or nonspecific.
| A
BAKER'S DOZEN OF IMPORTANT THALAMIC NUCLEI |
| KEY |
NUCLEUS |
MAJOR
SUBCORTICAL INPUT |
MAJOR
OUTPUT |
| SENSORY
RELAY |
| 1 |
Ventral
posterior lateral |
Medial
lemniscus and ALS |
Postcentral
gyrus |
| 2 |
Ventral
posterior medial |
Trigeminothalamic
tract |
Postcentral
gyrus |
| 3 |
Lateral
geniculate nucleus |
Optic tract |
Medial
occipital cortex |
| 4 |
Medial
geniculate nucleus |
Brachium
inferior colliculus |
Transverse
temporal gyri |
| MOTOR
RELAY |
| 5 |
Ventrall
lateral nucleus |
Cerebellum
(VLp); basal ganglia (VLa) |
Precentral
& premotor cortex |
| 6 |
Ventral
anterior nucleus |
Basal ganglia,
cerebellum |
Motor &
premotor Cortex |
| ASSOCIATION
RELAY |
| 7 |
Anterior
nucleus |
Mammillothalamic
tract |
Cingulate
gyrus (limbic) |
| 8 |
Lateral
dorsal nucleus |
Limbic
forebrain, septal area |
Cingulate
Gyrus & Parahippocampal Gyrus |
| 9 |
Medial
dorsal nucleus |
Amygdala,
septal area, anterior hypothalamus |
Prefrontal
Cortex |
| 10 |
Pulvinar |
Optic tract
& superior colliculus |
Visual
association cortex |
| INTRALAMINAR
NUCLEI ARE NONSPECIFIC |
| 12
|
Centromedian |
Found in
internal medullary lamina |
Collaterals
to widespread cortical areas (primarily motor and premotor)
& striatum |
| 13 |
Reticular |
Found in
external medullary lamina |
Thalamus |
Internal Capsule -
Thick band of fibers to and from cerebral cortex.
It is lateral to the thalamus (posterior limb), and lateral to the
Head of caudate nucleus (anterior limb), and between these is a
bend (genu) which is at the level of the interventricular foramen
(of Monro).
Consider the Following Questions ...
- What are the names of the thalamic nuclei identified as sensory relay? Motor relay nuclei? Describe the efferent projections from these nuclei to the cerebral cortex.
- What are the nuclei medial to the internal capsule, and what are the major functional components of the posterior limb of the internal capsule?
- The dorsal medial nucleus and Pulvinar are "association nuclei"; to what areas of cortex do they project?
