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Flashcards in Thalamus Deck (48):
1

Five roles of the thalamus

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

2

Different EEG bands are divided by _

frequency

3

Delta wave frequency

0-3 Hz

4

Delta wave amplitude (high or low)

high

5

Delta waves are seen during...

deep sleep in adults

6

Theta wave frequency

4-7 Hz

7

Theta waves are seen during...

light sleep in adults
normal in children when awake

8

Alpha wave frequency

8-12 Hz

9

Alpha waves are seen during...

Arousal when relaxed with eyes closed

10

Beta wave frequency

12-30 Hz

11

Beta waves are seen during...

Busy/anxious thinking & active concentration

12

Alpha waves are located...

posteriorly, higher on dominant side

13

Beta waves are located...

mostly frontally, symmetrically distributed

14

Gamma wave frequency

26-100 Hz

15

Gamma waves are seen during...

specific cognitive or motor functions
theorised to be involved in the binding problem

16

Thalamus location

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

17

Thalami are joined by the _

interthalamic adhesion

18

Cell groups of the thalamus

mediodorsal, lateral, anterior

19

Cell groups of the thalamus are divided by

the internal medullary lamina

20

Functional categorisation of thalamic nuclei

relay/specific
non-specific
associative

21

Relay nuclei

reciprocally connected to specific motor/sensory areas of cortex

22

Example of non-specific thalamic nuclei

intralaminar nuclei
reticular nuclei

23

Associative nuclei

reciprocally connected to associated areas of th cortex

24

Structural divisions of the thalamic nuclei

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

25

AN is part of _ circuit

Papez circuit (decalarative memory)

26

Afferent supply comes from _ via _

mammillary body of hypothalamus
mammilothalamic tract

27

AN projects to _

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

28

Synchronisation of _ waves between AN and hippocampus

theta

29

Result of mammillothalamic tract damage?

Memory and language impairement

30

Result of disconnection of mammillary bodues from Papez circuit?

Amnaesia

31

Korsakoffs Syndrome

degeneration of AN due to thiamine deficiency in alcoholism

32

Three divisions of VNG

ventral anterior
ventral lateral
ventral posterior

33

VA receives afferents from the _ and projects to the _

globus pallidus
prefrontal cortex & premotor cortex

34

VA forms the _ loop

cortical loop of the basal ganglia

35

VL receives afferents from _ and projects to the _

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

36

VL forms part of the _ loop

motor loop of the basal ganglia

37

Disease associated with basal ganglia disorders

Parkinson's (movement abnormalities)

38

What is abnormal about thalami of Parkinson's patients?

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

39

VP receives afferents from _ and projects to the _

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)

40

LGN receives afferents from _ and projects to the _

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

41

LGN basic structure

layers of cell bodies with neutropil between

42

MGN receives afferents from _ and projects to the _

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

43

Two non-specific nuclei

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

44

Three intralaminar nuclei and their associated loops

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

45

Result of intralaminar nuclei damage

Reduction in pain perception and in conciousness level

46

Reticular nucleus overall function

Dampen down thalamic output to the cortex

47

Thalamic peduncles

four bundles connecting the thalamus and the cortex

48

Four thalamic peduncles & their paths

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)