Lecture 5 - Basal Ganglia & Diencephalon

Question 1

What are the three types of white matter tracts?

Answer 1

We have three different types of tracts in the brain, the projection, commissural, and association tracts.

Question 2

Where do the projection tracts extend?

Answer 2

The projection tracts extend vertically from the brain to the spinal cord

Question 3

What do the projection tracts create?

Answer 3

The internal capsule

Question 4

Where do commissural tracts cross?

Answer 4

From one hemisphere to the other

Question 5

What is the major commissural tract?

Answer 5

The corpus callosum is the major commissural tract.

Question 6

What are the anatomical components of the corpus callosum? (4)

Answer 6

The splenium, body, genu, and rostrum

Question 7

Where are the rostrum and genu located and what do they connect? -of what bitch

Answer 7

The rostrum and genu are both located anteriorly and connect neurons in the frontal lobe. Genu is located above rostrum.

Question 8

Where is the body of the corpus callosum located and what does it connect?

Answer 8

The body is found in the middle of the corpus callosum and it connects parts of the frontal and parietal lobe.

Question 9

Where is the splenium of the corpus callosum located and what does it connect?

Answer 9

The splenium is the most posterior of the corpus callosum and it connects the neurons temporal and occipital lobes.

Question 10

What do the association tracts connect?

Answer 10

Association tracts connect lobes and gyri within the hemisphere.

Question 11

What is the basal ganglia?

Answer 11

The basal ganglia (basal nuclei) are a collection of neurons at the base of the brain

Question 12

What forms the lentiform nucleus?

Answer 12

The putamen (superficial) and globus pallidus (deep)

Question 13

What forms the corpus striatum?

Answer 13

The lentiform nucleus and the caudate nucleus

Question 14

What are the different parts of the caudate nucleus?

Answer 14

The caudate nucleus has a head, body and tail.

Question 15

What is found at the tail of the caudate nucleus?

Answer 15

At the tail of the caudate nucleus we have the amygdaloid nucleus which is part of the limbic system (not part of basal ganglia)

Question 16

What makes up the diencephalon?

Answer 16

The diencephalon is made up of three-paired structures, the thalamus, hypothalamus, and epithalamus.

Question 17

What % of the diencephalon does the thalamus make up?

Answer 17

80%

Question 18

What ventricle is the thalamus associated with?

Answer 18

The thalamus is associated with the 3rd ventricle and forms its walls.

Question 19

What connects the thalami?

Answer 19

The interthalamic adhesion (intermediate mass).

Question 20

What does the anterior commissure include?

Answer 20

Axons that connect the middle and inferior temporal gyri of the two sides

Question 21

What is the basal ganglia functionally associated with?

Answer 21

The subthalamic nuclei and the substantia nigra

Question 22

Where is the posterior limb of the internal capsule located?

Answer 22

Between the lentiform nucleus and thalamus

Question 23

Where is the anterior limb of the internal capsule located?

Answer 23

Between the lentiform and caudate nuclei

Question 24

Where does the basal ganglia recieve inputs from?

Answer 24

The substantia nigra and motor cortex

Question 25

How does basal ganglia have access to motor neurons in the cerebral cortex?

Answer 25

Through the thalamus as there is no direct access - hence the coritcal-basal ganglia-thalamic-cortical loop

Question 26

What is the basal ganglia’s function in motor control?

Answer 26

Inhibition of unnecessary movements/ act as a brake

Regulate attention and cognition

Question 27

How does basal ganglia influence spinal cord motor neurons?

Answer 27

Indirectly

Question 28

What is Parkinson’s disease?

Answer 28

Substantia nigra dopamine neuron degeneration

Question 29

What are the motor deficits found in Parkinson’s disease?

Answer 29

Rigidity
Tremor (at rest)
Difficulty initiating movement
Postural instability
Shuffling gait
Stiff facial expression

Question 30

What are possible treatments of Parkinson’s?

Answer 30

Replacement of dopamine
Stem cell therapy
Deep brain stimulation

Question 31

What is the function of the thalamus?

Answer 31

The thalamus is the gateway to the cerebral cortex and its functions are to relay sensation, motor activities, cortical arousal, and memory.

Question 32

Where is the hypothalamus located?

Answer 32

The hypothalamus is located below the thalamus and is superior to the brainstem

Question 33

What seperates the thalamus and hypothalamus?

Answer 33

The hypothalamic sulcus

Question 34

What ventricle is the hypothalamus associated with?

Answer 34

Third ventricle - forms the inferolateral wall of the third ventricle

Question 35

What is the relationship between hypothalamus and pineal gland?

Answer 35

The hypothalamus has neuronal control over the pituitary gland

Question 36

Where does the hypothalamus extend from?

Answer 36

The optic chiasma

Question 37

What are the main homeostatic roles of the hypothalamus? (7)

Answer 37

Autonomic control centre (respiration)
Centre for emotional response (limbic system)
Body temperature regulation (thermosensitive neurons)
Regulation of food intake (appetite and satiety centres)
Regulation of water balance and thirst (thirst centre)
Regulation of sleep-wake cycle (with pineal gland)
Control of endocrine system functioning (ovaries and testes to produce either egg or sperm)

Question 38

What is the epithalamus?

Answer 38

The epithalamus is a small, cone-shaped body that is attached to the roof of the third ventricle.

Question 39

What does the epithalamus contain?

Answer 39

The epithalamus contains the pineal gland and has calcium salts (pineal salt) in adults (radiopaque).

Question 40

What important hormone does the epithalamus produce?

Answer 40

The epithalamus generates melatonin.