Diencephalon And Internal Capsule

Question 0

What is the function of the diencephalon?

Answer 0

Relay station for majority of motor and sensory connections

Question 1

What structures are contained in the diencephalon?

Answer 1

Thalamus
Hypothalamus
Epithalamus (pineal gland)
Subthalamus
Pretectum

Question 2

What is the function of the thalamus?

Answer 2

Major relay station for sensory and motor information from cortex, basal ganglia, cerebellum and limbic system

Regulates the flow of information to the cortex
Serves as a selective filter of information
Regulates activity level of cortical neurons
All sensory pathways relay in the thalamus

Question 3

What are the three types of thalamic nuclei?

Answer 3

Relay nuclei
Association nuclei
Nonspecific nuclei

**nuclei of thalamus (except reticular nucleus) project to the ipsilateral cerebral cortex

Question 4

General function of relay nuclei?

Answer 4

Receive specific information and serve as relay stations

Send information directly to specific localized area of cortex

Question 5

Ventral posteriolateral (relay nuclei) function? sensory

Answer 5

Receive input from trunk and limbs from spinothalamic and medial lemniscus; projects to primary somatosensory cortex

Question 6

Ventral posteromedial (relay nuclei) function? sensory

Answer 6

Receives taste information from medulla and vestibular information from vestibular nuclei

Question 7

Medial geniculate (relay nucleus) function? sensory

Answer 7

Auditory system - receives fibers from midbrain; projects to auditory cortex of temporal lobe

Question 8

Lateral geniculate (relay nucleus) function? sensory

Answer 8

Visual system - termination site of optic tract; projects to internal capsule and optic radiation

Question 9

Ventral anterior and ventral lateral (relay nuclei) function? motor

Answer 9

Receive fibers from basal ganglia and cerebellum; project to motor area of frontal lobe

Question 10

Association nuclei general function?

Answer 10

Connect reciprocally to large areas of cortex
Axons project from association nuclei to the cortex and axons project cortex to association nuclei
Distributes and gates the information between cortical structures

Question 11

Anterior nucleus and lateral dorsal nucleus (association nuclei) function?

Answer 11

Part of the limbic system; involved in control of instinctive drives, emotional aspects of behavior and memory

Question 12

Dorsal medial nucleus (association nucleus) function?

Answer 12

Extensive reciprocal connections with the cortex of frontal lobe; controls mood and emotions

Question 13

Lateral posterior nucleus (association nucleus) function?

Answer 13

Connects with sensory association area of parietal lobe

Question 14

Nonspecific thalamus nuclei functions?

Answer 14

Receive multiple types of input and project to widespread areas of the cortex
Regulate consciousness, arousal and attention

Question 15

Primary blood supply to thalamus?

Answer 15

Branches of the posterior cerebral artery

Question 16

Thalamic impairment would result in?

Answer 16

Interrupt ascending pathways
Compromises or eliminates contralateral sensation
(Usually proprioception is most affected)
Rarely produces thalamic pain syndrome
(Produces severe contralateral pain with or without external stimuli)

Question 17

Hypothalamus general functions?

Answer 17

Integrates behaviors with visceral functions (coordinating eating with digestive activity)
Homeostasis (body temp, metabolic rate, blood pressure, water intake/excretion, digestion)
Eating, reproductive and defensive behaviors

Question 18

Other hypothalamus functions?

Answer 18

Emotional expression of pleasure, rage, fear and aversion
Regulation of circadian rhythms
Endocrine regulation of growth, metabolism, and reproductive organs

Question 19

How does the hypothalamus regulate bodily functions?

Answer 19

Hypothalamus functions are carried out through regulation of the pituitary gland secretions (hormones) and through efferent neural connection with the cortex

Question 20

Anterior hypothalamus functions?

Answer 20

Anterior area influences parasympathetic nervous system through projections to brainstem parasympathetic nuclei
dissipates heat

Question 21

Middle hypothalamus functions?

Answer 21

Blood pressure, heart rate, satiety

Question 22

Posterior hypothalamus functions?

Answer 22

Posterior area influences sympathetic nervous system through projections to lateral gray horn
conserves heat

Question 23

Hypothalamus output goes to?

Answer 23

Cerebral cortex, hippocampus, amygdala, pituitary gland, thalamus, brainstem and spinal cord

Question 24

Blood supply to the hypothalamus?

Answer 24

Penetrating branches of the anterior cerebral artery and anterior communicating artery supply the anteromedial regions. Penetrating branches of the posterior cerebral artery and posterior communicating artery supply the posteromedial regions.

Question 25

Epithalamus facts?

Answer 25

Forms roof over third ventricle Houses pineal gland Includes choroid plexus (makes CSF)

Question 26

Pineal gland functions?

Answer 26

Endocrine gland associated with seasonal cycles Regulates sleep-wake cycles (circadian rhythms) Secretes melatonin Influences secretions of pituitary gland, adrenals, parathyroids and islets of langerhans

Question 27

Subthalamus functions?

Answer 27

Part of basal ganglia circuit Involved in regulating movement - rhythmic movement Facilitates basal ganglia output nuclei Contains projection fibers **stimulation of this area can be used to treat Parkinson's**

Question 28

Pretectum function?

Answer 28

Receives binocular input | Pupillary light reflex - produces change in pupil size in response to light input

Question 29

Posterior limb of internal capsule function?

Answer 29

``` Contains corticospinal tract fibers Sensory fibers (including the medial lemniscus and the anterolateral system from the body) ```

Question 30

Genu of internal capsule functions?

Answer 30

Contains corticobulbar fibers, which run between the cortex and the brainstem

Question 31

Anterior limb of internal capsule functions?

Answer 31

Fibers from frontal cortex to pons | Fibers connecting medial and anterior nuclei of the thalamus to frontal lobes

Question 32

Retrolenticular part of internal capsule functions?

Answer 32

Fibers from optic system, coming from lateral geniculate nucleus of thalamus More posteriorly, becomes the optic radiation

Question 33

Internal capsule impairment?

Answer 33

Prevents messages from corticospinal, corticobulbar, corticopontine, corticoreticular, and thalamocortical fibers from reaching destination Contralateral decrease in voluntary movement Contralateral decrease in automatics movement control Contralateral loss of conscious somatosensation

Question 34

Internal capsule blood supply?

Answer 34

Middle cerebral artery

Question 35

Association fibers function? Ex?

Answer 35

Interconnect cortical structures within the same cerebral hemisphere Ex: arcuate fasciculus (facilitates language); inferior longitudinal fasciculus (occipital to temporal lobe - contributes to visual recognition)

Question 36

Commissural fiber function? Ex?

Answer 36

Fibers that run from one hemisphere to the other | Ex: corpus callosum; anterior commissure

Question 37

Projection fibers function? Ex?

Answer 37

Fibers that pass between the cortex and subcortical structures Ex: internal capsule