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Neuro COPY > Neuro 6: Thalamus and hypothalamus > Flashcards

Neuro 6: Thalamus and hypothalamus Flashcards

1
Q

List the 3 parts of the diencephalon

A

Thalamus, hypothalamus and subthalamus

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2
Q

What intersects the thalamus

A

3rd ventricle

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3
Q

Locate the thalamus

A

Ventral to the lateral ventricle

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4
Q

Which 2 thalamic nuclei are associated with the resticular activating system

A

RETICULAR nucleus (all around the outside of the thalamus)… does not project to cortex, provides negative feedback to the thalamus

and

INTRALAMINAR… projects to all other areas of cortex including medial temporal lobe structures (amygdala, hippocampus and basal ganglia)

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5
Q

State the function of the thalamus

A

Relay site for lots of inputs or outputs

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6
Q

Which sense does not travel through the thalamus

A

Olfactory

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7
Q

The thalamus only enhances signals t/f

A

F it can restrict too

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8
Q

Which thalamic nucleus is responsible for transmitting fine touch

A

Ventral posterior lateral nucleus

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9
Q

What are intalaminar nuclei

A

Thalamic nucleus: Project to MEDIAL temporal lobe structures like amygdala, hippocampus and basal ganglia

(and to rest of cortex)

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10
Q

What type of neurons exist in the intralaminar neuclei

A

Glutamaterigic

Loss of intralaminar nucleus neurons asociated with parkinsons

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11
Q

What nucleus forms the outer covering of the thalamus +

what type of neurons here

A

Reticular nucleus (thalamic)- doesn’t connect with distal regions, but instead all other thalamic nuclei

GABAergic (compared to glutamatergic in intralaminar)

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12
Q

Function of reticular nucleus

A

Mostly inhibitory on thalamic nuclei

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13
Q

Where do reticular nuclei receive inputs from

A

receives sensory information from thalamic neurons via collaterals of their axons

Modulates thalamic activity -ve feedback depending on this input

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14
Q

Where is the reticular formation found and what is it

A

Area of grey matter in brainstem

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15
Q

What is ascending reticular activating system

A

Consciousness and arousal- degrees of wakefullness proportional to activity of ARAS Intralaminar and reticular nucleus receive input from the ARAS

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16
Q

How can the RAS increase activity in the cortex

A

DIRECT: can increase stimulation of intralaminar nuclei, so this directly increases activity of cortical areas

INDIREECT: can cause the reticular nucleus to increase activity of thalamic nuclei, which would then lead to increase in cortical activity too

the greater the level of activity coming through the reticular formation into the thalamus, the more activated and stimulated the cortex becomes

17
Q

Hypothalamus has 4 functions

A

Feeding, mating, fleeing and flighting

  • Connections with autonomic NS (PVN neurons project to pre-autonomic neurons in spinal cord)
  • Endocrine connections
  • Behaviour control (feeding behaviour)
18
Q

How does hypothalamus perform the four functions

A

Hypothalamic nuclei such as PARAVENTRICULAR NUCLEI:

Send projections to ANS and to posterior pituitary gland

Can impact on CVS function and renal function within ANS

https://en.wikipedia.org/wiki/Paraventricular_nucleus_of_hypothalamus#Neurons

Magnocellular release oxytocin and vasopressin

Parvocellular travel dwon to the spinal cord and also release hormones into the hypophysial system to influence ant. pituitary function

19
Q

State other function of hypothalamus,

A

Role in feeding as it has many receptors for hormones produced in the gut…. also to do with PARAVENTRICULAR NUCLEUS

20
Q

State the 3 types of paraventricular

A

Parvocellular neurosecretory neurons

magnocellular neuronsecretory neurons

centrally projecting neurons (another type of parvocellular)

21
Q

Where do the centrally projecting parvocellular neurons travel

A

Travel down the spinal cord and synapse onto preganglionic sympathetic nerves–> changing heart rate, constriction, renal etc

22
Q

Function of magnocellular neurons

A

Extend to post. pit to stimulate vasopressin or oxytocin release which then impact on water reabsorption (ADH) and uterine contraction (uterine)

23
Q

Effect of activating and inhibiting PVN on food,

A

Activating leads to fullness and inhibition leads to feeding

24
Q

What is the suprachiasmatic

A

Involved in sleep/wake cycles, reponsive to light. Light sensitive retinal ganglion cells are connected to hypothalamic suprachiasmatic nuclei, particularly blue light (which activate the suprachiasmatic nuclei)

25
Q

How does suprachiasmatic nucleus influence sleep and wake cycles

A

SC nuclei neurons synapse with paraventricular nuclei which travel down to the spinal cord, impact on the intermediolateral column then up the cervical spinal cord, synapse on the superior cervical ganglion and then travel to the pineal gland which regulates melatonin release

26
Q

What would lesions of the SCN cause

A

Sleep disturbances, which is a symptom of schizophrenia

27
Q

What do the following control:
Amygdala
Basal Ganglia
Hippocampus

A

A: fear, emotion, anxiety
BG: movement
HC: memory

28
Q

Loss of neurons from the intralaminar nuclei are associated with what problems

A

Parkinson’s and progressive supranuclear palsy (PSP)

THINK- it goes to BG so going to affect movement e.g. like in parkinsons

29
Q

T/F hypothalamus usually has contralateral connections with other nuclei

A

F: mostly ipsilateral

30
Q 
Outline the area of cortex associated with each of the following specific thalamic nuclei: 
Ventral lateral 
Ventral anterior 
Ventroposterolateral 
Ventroposteromedial 
Laterial geniculate 
Medial geniculate
A

Ventral lateral and ventral anterior - motor cortices (primary, premotor and supplemetnary)

Ventroposterolateral- somatosensory (body) (you know it’s lateral cos the body goes more lateral than the head!)

Ventroposteromedial- somatosensory (head)… so receives fibers from the solitary tract and trigeminal nerve to the post central gyrus

Laterial geniculate- visual (thin L for Light)

Medial geniculate- auditory (think M for Music)

31
Q

State the different types of thalamic nuclei

A

Speicifc- going to primary cortical areas

Association- connected to association cortex

Reticular- not connected to cortex, connected to other thalamic nuclei

Intralaminar- connected to all cortical areas

32
Q

Outline the type of association cortex linked to the following thalamic nuclei:

Anterior, lateral dorsal and dorsomedial

Lateral posterior and pulvinar

A

Anterior, lateral dorsal and dorsomedial: Mamillary bodies (ant), hypothalamus (lat dorsal) and cingulate and prefrontal

Lateral posterior and pulvinar: parieto-temporo-occipital and prefrontal

33
Q

Examples of hypothalamic structural damage

A

Craniopharyngioma, other tumours (glioma, meningioma etc), sarcoidosis and langerhans cell histiocytosis

34
Q

T/f hypothalamus has largely ipsilateral connections with other nuclei

A

T

35
Q

Which area of the cortex is the hypothalamus associated with

A

Olfactor system and limbic system

36
Q

How does hypothalamus control behaviour

A

We already said it contros 4 Fs using paraventricular nucleus etc.

Behavioural control includes; 
Eating and drinking  
Expression of emotion  
Sexual behaviour  
Circadian rhythm 
Memory

Hypothalamus and limbic system have a motivational process.. there is a pleasure centre in the limbic system… i.e. eating when you are hungry achieves pleasure… reinforces benefical behaviour.

Goes wrong in addiction

37
Q

Hypothalamic tumour presenting symptoms

A

Polydipsia, plyuria, absent menses

38
Q

Other thing sthan hypothalamic tumour can lead to

A

Laile emotions, inapproproaute sexual behaviour, memory lapse, temp fluctaution, thryoid/adrenal/gonadal dysfunction, hyperphagia

39
Q

Where do association nuclei of the thalamus (i.e. those which relate to association cortex) get their major input from

A

From the cortex.

E.g. pulvinar, the largest association nucleus, receives information from the superior colliculus and also the association cortex. is receives afferent projections from the superior colliculus as well as from the association cortex. It projects to secondary visual areas and to association areas in the parietotemporal region. This contributes to visual perception and eye movements

Neuro COPY (16 decks)

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