Thalamus

Question 1

Five roles of the thalamus

Answer 1

1. Relay of sensory info to cortex
2. Smooth & accurate movements
3. Alertness & emotional aspect of sensation
4. Cortical pacemaker
5. Compensates for dysfunctions in other areas

Question 2

Different EEG bands are divided by _

Answer 2

frequency

Question 3

Delta wave frequency

Answer 3

0-3 Hz

Question 4

Delta wave amplitude (high or low)

Answer 4

high

Question 5

Delta waves are seen during…

Answer 5

deep sleep in adults

Question 6

Theta wave frequency

Answer 6

4-7 Hz

Question 7

Theta waves are seen during…

Answer 7

light sleep in adults

normal in children when awake

Question 8

Alpha wave frequency

Answer 8

8-12 Hz

Question 9

Alpha waves are seen during…

Answer 9

Arousal when relaxed with eyes closed

Question 10

Beta wave frequency

Answer 10

12-30 Hz

Question 11

Beta waves are seen during…

Answer 11

Busy/anxious thinking & active concentration

Question 12

Alpha waves are located…

Answer 12

posteriorly, higher on dominant side

Question 13

Beta waves are located…

Answer 13

mostly frontally, symmetrically distributed

Question 14

Gamma wave frequency

Answer 14

26-100 Hz

Question 15

Gamma waves are seen during…

Answer 15

specific cognitive or motor functions

theorised to be involved in the binding problem

Question 16

Thalamus location

Answer 16

• largest structure of diencephalon - between the midbrain and cerebral hemispheres
• forms the lateral walls of the third ventricle

Question 17

Thalami are joined by the _

Answer 17

interthalamic adhesion

Question 18

Cell groups of the thalamus

Answer 18

mediodorsal, lateral, anterior

Question 19

Cell groups of the thalamus are divided by

Answer 19

the internal medullary lamina

Question 20

Functional categorisation of thalamic nuclei

Answer 20

relay/specific
non-specific
associative

Question 21

Relay nuclei

Answer 21

reciprocally connected to specific motor/sensory areas of cortex

Question 22

Example of non-specific thalamic nuclei

Answer 22

intralaminar nuclei

reticular nuclei

Question 23

Associative nuclei

Answer 23

reciprocally connected to associated areas of th cortex

Question 24

Structural divisions of the thalamic nuclei

Answer 24

Anterior nuclei (AN)
Medial dorsal nuclei (MD)
Ventral nuclei (VNG)/

Question 25

AN is part of _ circuit

Answer 25

Papez circuit (decalarative memory)

Question 26

Afferent supply comes from _ via _

Answer 26

mammillary body of hypothalamus | mammilothalamic tract

Question 27

AN projects to _

Answer 27

cingulate gyrus | from there on to entorhinal cortex, hippocampal formation and hypothalamus

Question 28

Synchronisation of _ waves between AN and hippocampus

Answer 28

theta

Question 29

Result of mammillothalamic tract damage?

Answer 29

Memory and language impairement

Question 30

Result of disconnection of mammillary bodues from Papez circuit?

Answer 30

Amnaesia

Question 31

Korsakoffs Syndrome

Answer 31

degeneration of AN due to thiamine deficiency in alcoholism

Question 32

Three divisions of VNG

Answer 32

ventral anterior ventral lateral ventral posterior

Question 33

VA receives afferents from the _ and projects to the _

Answer 33

globus pallidus | prefrontal cortex & premotor cortex

Question 34

VA forms the _ loop

Answer 34

cortical loop of the basal ganglia

Question 35

VL receives afferents from _ and projects to the _

Answer 35

``` anteriorly: globus pallidus supplementary motor cortex posteriorly: contralateral cerebellum (via dentatorubrothamocorical tract) primary motor cortex ```

Question 36

VL forms part of the _ loop

Answer 36

motor loop of the basal ganglia

Question 37

Disease associated with basal ganglia disorders

Answer 37

Parkinson's (movement abnormalities)

Question 38

What is abnormal about thalami of Parkinson's patients?

Answer 38

Display sleep-like Theta rhythms when awake | Ablating thalamus can reduce or abolish tremors and rigidity

Question 39

VP receives afferents from _ and projects to the _

Answer 39

all fibres carrying general sensory info from contralateral head, neck and body to a conscious level (via medial, spinal and trigeminal lemnisci) somatosensory cortex (lesser bundle projects to the second somatic sensory area of the parietal lobe)

Question 40

LGN receives afferents from _ and projects to the _

Answer 40

``` retinal fibres (via optic tract) primary visual cortex (via optic radiation) ```

Question 41

LGN basic structure

Answer 41

layers of cell bodies with neutropil between

Question 42

MGN receives afferents from _ and projects to the _

Answer 42

inferior colliculus of midbrain (via inferior brachium) | primary auditory cortex

Question 43

Two non-specific nuclei

Answer 43

``` Intralaminar nuclei (internal medullary lamina) reticular nuclei (between external medullary lamina and internal capsule on the lateral part of the thalamus) ```

Question 44

Three intralaminar nuclei and their associated loops

Answer 44

Anterior nuclei - limbic-cingulate gyrus circuit in the emotional loop Medial dorsal nuclei - feedback loop with frontal cortices, maintains wakefulness in executive frontal processing areas Centromedian nucleus - feedback loop with frontal and basal ganglia for motor alertness

Question 45

Result of intralaminar nuclei damage

Answer 45

Reduction in pain perception and in conciousness level

Question 46

Reticular nucleus overall function

Answer 46

Dampen down thalamic output to the cortex

Question 47

Thalamic peduncles

Answer 47

four bundles connecting the thalamus and the cortex

Question 48

Four thalamic peduncles & their paths

Answer 48

anterior (prefrontal cortex and cingulate gyrus via the anterior limb of the internal capsule) superior (premotor, motor and somatosensory cortex via posterior limb of internal capsule) posterior (occipital lobe and posterior parts of parietal and temporal lobes via retrolentiform part of internal capsule) inferior (temporal and orbital cortex via lentiform nucleus)