Diencephalon Structure and Function Flashcards
1
Q
Describe the Diencephalon
A
- embryologically between the telencephalon and mesencephalon-between the cerebral cortex and the brain stem
- medial to the internal capsule
- divided in the midline by the 3rd ventricle
2
Q
Diencephalon subdivisions
A
- Epithlamus
- Dorsal Thalamus
- Subthalamus
- Hypothalamus
3
Q
What is the epithalamus divided into
A
- Habenular nuclear complex
- pineal gland
- posterior commissure
4
Q
What is the dorsal thalamus divided into
A
- thalamic nuclei
- external medullary lamina
- internal medullary lamina
5
Q
What is the ventral thalamus divided into
A
- reticular nucleus of thalamus
- ventral lateral geniculate nucleus
6
Q
what is the subthalamic nucleus divided into
A
- zona incerta
- subthalamic nucleus (luys)
7
Q
subdivisions of the hypothalamus
A
- hypothalamic nuclei
- infundibulum
- hypophysis (pituitary land)
- hypophyseal portal system
8
Q
Blood supply to the thalamus
A
- anterior communicating artery
- posterior communicating artery
- anterior cerebral artery
- posterior cerebral artery
- internal carotid artery
9
Q
Dorsal thalamus
A
- medial to the posterior limb of the internal capsule
- surrounds the 3rd ventricle
- part of the diencephaln
10
Q
Major functions of the thalamus
A
- relays all sensory information to the cerebral cortex (olfactory input to the thalamus is from the pririform cortex)
- relays information about motor activities to the cerebral cortex
- integrates sensory information from different modalities and projects to association cortex
- relays emotional an affectve information to the cotex
- part of the papez circuit of the limbic system, projects to limbic cortex
- intimately involved in the control of alertness, arousal and sleep
- under direct cortical feedback and control: reciprocal connections between thalamus and cortex
11
Q
Anterior nuclear group
- afferent
- efferent
- functions
A
- afferent: Mammillary body
- efferent: cingulate gyrus
- functions: limbic
12
Q
VA nuclei
- tier
- afferent
- efferent
- functions
A
- afferent: Gpi and SNr
- efferent: Area 6 (premotor)
- function: motor
13
Q
VL
- tier:
- afferent:
- efferent:
- functions:
A
- tier: Lateral-Ventral
- afferent: Dentate; GPi and SNr
- efferent: Areas 4 and 6
- functions: Motor
14
Q
VPL
- tier:
- afferent:
- efferent:
- functions:
A
- tier: Lateral-Ventral
- afferent: DC-ML and STT
- efferent: Areas 3, 1, 2
- functions: SS (body)
15
Q
VPM
- tier:
- afferent:
- efferent:
- functions:
A
- tier: Lateral Ventral
- afferent: Trigeminal nuclei
- efferent: Areas 3, 1, 2
- functions: SS (face)
16
Q
LGN
- tier:
- afferent:
- efferent:
- functions:
A
- tier: Lateral Ventral
- afferent: Retina
- efferent: Area 17
- functions: Vision
17
Q
MGN
- tier:
- afferent:
- efferent:
- functions:
A
- tier: Lateral Ventral
- afferent: IC
- efferent: Areas 41, 42
- functions: Audition
18
Q
LD
- tier:
- afferent:
- efferent:
- functions:
A
- tier: Lateral dorsal
- afferent: cingulate gyrus
- efferent: gingulate gyrus
- functions: emotional exp
19
Q
LP
- tier:
- afferent:
- efferent:
- functions:
A
- tier: Lateral Dorsal
- afferent: Parietal cortex
- efferent: parietal cortex
- functions: sensory integration
20
Q
Pulvinar
- tier:
- afferent:
- efferent:
- functions:
A
- tier: Lateral dorsal
- afferent: SC; Parietal occipital and temporal cortices (POT)
- efferent: POT cortex
- functions: sensory integration
21
Q
MD
- tier:
- afferent:
- efferent:
- functions:
A
- tier: Medial group
- afferent: amygdala, Olf, HT
- efferent: Prefrontal cortex
- functions: Limbic
22
Q
Midline nuclei
- afferent:
- efferent:
- functions:
A
- afferent: reticular formation and hypothalamus
- efferent: basal forebrain
- functions: limbic
23
Q
Intralaminar nuclei
-centro-median (CM)
A
- afferent: reticular formation, spinothalamic tract, globus pallidus, and cortical areas
- efferent: basal ganglia and wide areas of cortex
- functions: role in pain, sleep and wakefulness
24
Q
Intralaminar nuclei: Centro-lateral (CL)
A
- afferent: reticular formation, spinothalamic tract, globus pallidus, and cortical areas
- efferent: basal ganglia and wide areas of cortex
- functions: role in pain, sleep and wakefulness
25
Q
Intralaminar nuclei: Parafascicularis (PF)
A
- afferent: reticular formation, spinothalamic tract, globus pallidus, and cortical areas
- efferent: basal ganglia and wide areas of cortex
- functions: role in pain, sleep and wakefulness
26
Q
Reticular nucleus
A
- afferent: cortex, thalamus, brainstem RF
- efferent: thalamic nuclei
- functions: modulation of thalamic activity
27
Q
Thalamic neuronal circuit
A
- afferent input communicates with thalamic relay neuron and thalamic interneuron
- thalamic relay neuron communicates with the cerebral cortex and the cerebral cortex communicates with the thalamic relay neuron. its a reciprocal relationship
- the thalamic interneuton communicates with the thaalamic relay neuron
28
Q
Thalamic syndrome
A
- usually caused by vascular lesion or tumor and is relatively rare
- usually involved damage to the lateral group of thalamic nucleus (VPL)
- initially, a transitory contralateral hemianalgesia
- soon, painful sensations occur with noxious stimuli
- later pain is provoked by pressure, touch, and vibration
- in time, a state of spontaneous, constant or paroxysmal pain is evoked on the affected side ( contralateral to the lesion) without any external stimulus ( Dysesthesia)
- The threshold for pain, temperature and tactile sensations, however is often raised on the affected side
- cut once pain is reached it has a strong emotional overtone to it
29
Q
Functional characteristic to non-specific system: Reticular Activating System RAS
A
- activated by repetitive low frequency stimulation
- interconnected with each other and reciprocally with specific thalamic nuclei
- repetitive stimulation of the non-specific thalamic nuclei evokes cortical recruitment response that waxes and wanes
- control the level of excitability of neurons over wide areas of cortex; affects one’s level of attention, alertness, and awareness
