7B. Diencephalon

Front 1

How many subdivisions of the thalamus are there?

Back 1

5

Front 2

What are the Thalamic subdivisions?

Back 2

1. Epithalamus
2. Dorsal thalamus(The Thalamus)
3. Ventral thalamus
4. Subthalamus
5. Hypothalamus

Front 3

3 components of the epithalamus:

Back 3

-Habenular nuclear complex
-Pineal gland
-Posterior commisure

Front 4

Habenula involved in:

Back 4

limbic system

Front 5

Pineal gland function:

Back 5

-Synthesizes serotonin and converts it to melatonin
-Regulates sleep/wake cycle

Front 6

what does the Posterior commissure link?

Back 6

-Pretectal and other nuclei of the brain.

Front 7

3 features of the Thalamus (dorsal)

Back 7

-Thalamic nuclei
-External medullary lamina
-Internal medullary lamina

Front 8

Function of the Thalamic nuclei?

Back 8

A strong link to the cerebral cortex

Front 9

What does the internal medullary lamina do?

Back 9

Slices the thalamus into 3 parts; Medial, lateral and anterior.

Front 10

What does the external medullary lamina do?

Back 10

Surrounds the thalamus

Front 11

What are the external and internal medullary lamina made of?

Back 11

Myelinated fibers

Front 12

What does the Thalamus surround?

Back 12

The 3rd ventricle

Front 13

What is the thalamus located medially to?

Back 13

The posterior limb of the internal capsule.

Front 14

What is the function of the thalamus?

Back 14

MAJOR GATEWAY TO THE CORTEX

Front 15

Why is the thalamus considered the major gateway to the cortex?

Back 15

-Relays all sensory info
-Relays motor info from the cerebellum, spinal cord, and brainstem
-Relays emotional info

Front 16

What does the thalamus do in addition to relaying information?

Back 16

Integrates it

Front 17

How is the Thalamus involved in emotion?

Back 17

It is part of the Papez circuit of the Limbic system that projects to the limbic cortex.

Front 18

What sensory information is NOT relayed via the thalamus?

Back 18

Olfactory input to the thalamus

Front 19

Where does olfactory input to the thalamus come from?

Back 19

The piriform cortex.

Front 20

What process is the thalamus intimately involved in?

Back 20

The control of alertness, arousal and sleep - via the Reticular Activating System.

Front 21

Does the thalamus only relay input to the cortex?

Back 21

No; it also recieves cortical input to allow reciprocal communication and feedback.

Front 22

What does the Ventral Thalamus subdivision consist of? (2 things)

Back 22

1. Reticular nucleus of thal
2. Ventral Lateral geniculate nucleus (LGN)

Front 23

2 components of the Subthalamus:

Back 23

-Subthalamic nucleus
-Zona incerta

Front 24

Where is the subthalamus located?

Back 24

Between the hypothalamus and the dorsal thalamus

Front 25

What is the Subthalamus involved in?

Back 25

The basal ganglia and extrapyramidal activity.

Front 26

What is the Hypothalamus?

Back 26

The controlling center of the ANS.

Front 27

What is the Hypothalamus involved in?

Back 27

-Neurobehavioral functions
-Regulation of hormone release by the hypophysis

Front 28

4 Components of the Hypothalamus:

Back 28

-Hypothalamic nuclei
-Infundibulum
-Hypophysis
-Hypophyseal portal system

Front 29

What is the hypophysis?

Back 29

The pituitary gland

Front 30

What supplies blood to the diencephalon?

Back 30

Mainly PCA

Front 31

Anterior nuclear group of thal:

Back 31

Limbic

Front 32

2 nuclei involved in the limbic cortex:

Back 32

-Anterior nuclear group
-Medial dorsal nucleus

Front 33

Ventral anterior nucleus:

Back 33

motor

Front 34

Ventral lateral nucleus:

Back 34

motor

Front 35

VPL

Back 35

ventral posterior lateral
Somatic sensation of contralateral body

Front 36

VPM

Back 36

ventral posterior medial nucleus
Somatic sensation of face

Front 37

LGN

Back 37

Vision
(lateral geniculate nucleus)

Front 38

MGN

Back 38

Audition

Front 39

Lateral dorsal nucleus

Back 39

Emotional expression

Front 40

Lateral posterior nucleus

Back 40

Sensory integration

Front 41

Pulvinar

Back 41

Primary integrator of sensory information

Front 42

Medial dorsal nucleus

Back 42

Limbic

Front 43

General nature of the Lateral-Ventral tier:

Back 43

Simple relays
(auditory, somatic sensation)

Front 44

General nature of the Lateral dorsal tier:

Back 44

Complex relays
(emotion, sensory info integration)

Front 45

3 diffuse projection nuclei located in the thalamus:

Back 45

1. Midline
2. Intralaminar
3. Reticular nuclei

Front 46

Function of the diffuse midline nuclei:

Back 46

Limbic

Front 47

Function of the diffuse Intralaminar nuclei:

Back 47

Pain, sleep, wakefulness

Front 48

Function of the diffuse Reticular nuclei:

Back 48

Modulation of thalamic activity

Front 49

Which nuclei are involved in the Reticular Activating System?

Back 49

All diffuse projection nuclei:
-Midline
-Intralaminar
-Reticular

Front 50

Which diffuse projection nuclei have a limbic function?

Back 50

Just the Midline

Front 51

2 Types of Thalamic neuronal circuits:

Back 51

-Direct
-Indirect

Front 52

Direct Thalamic circuit:

Back 52

1. Afferent input
2. Thalamic relay neurons
3. Cerebral cortex
4. Back to thalamus

Front 53

Indirect Thalamic circuit:

Back 53

1. Afferent input
2. Thalamic INTERNEURONS
3. Thalamic relay neurons
4. Cerebral cortex
etc.

Front 54

How common is Thalamic syndrome, and what are 2 common causes?

Back 54

It is rare, but caused by:
-Vascular lesions (ischemia)
-Tumors

Front 55

What nucleus of the thalamus is most often affected by Thalamic Syndrome?

Back 55

VPL

Front 56

What is the initial result of damage to the VPL?

Back 56

Transitory Hemialgesia - loss of sensation from the contralateral side.

Front 57

What happens to the patient after the initial transitory period of sensation loss?

Back 57

Painful sensations with noxious stimuli

Front 58

What can result from progression of Thalamic syndrome?

Back 58

Constant or recurrent pain on the contralateral side to the lesion, not caused by any stimulus.

Front 59

What is it called when pain is felt without a stimulus?

Back 59

Dyesthesia.

Front 60

How does the sensory system respond to Thalamic syndrome?

Back 60

By increasing the threshold of response to stimuli for pain, temp, and tactile stimulus.

Front 61

How is pain sensation changed by Thalamic syndrome?

Back 61

Though higher, once the threshold is reached the pain felt has a strong emotional overtone to it.

Front 62

What is the Non-specific System of the thalamus?

Back 62

A system that projects to a wide area of the cortex.

Front 63

What is the Nonspecific system activated by?

Back 63

Repetitive, low frequency stimulation (like biochem lectures).

Front 64

2 types of connections in the non-specific system:

Back 64

-Interconnections with each other
-Reciprocal connections with specific thalamic nuclei

Front 65

What is the effect of repetitive stimulation of the Nonspecific System?

Back 65

Waxing and waning activity in the cortex

Front 66

What does the Nonspecific system control?

Back 66

The level of neuron excitability over wide areas of the cortex.

Front 67

The HYPOTHALAMUS is located where?

Back 67

Ventral diencephalon - in the walls and floor of the 3rd ventricle.

Front 68

What is the hypothalamus connected to, and by what?

Back 68

Hypophysis (pituitary) via the Infundibulum

Front 69

How is the hypophysis connected to the
-Anterior pituitary
-Posterior pituitary

Back 69

Anterior: via the portal system
Posterior: via neural projections

Front 70

What is the hypothalamus essential for controlling? What is it called?

Back 70

ANS - the HEAD GANGLION OF THE ANS

Front 71

What is the hypothalamus concerned with?

Back 71

-Homeostatic regulation
-Survival of the individual and THE SPECIES!!!