Exam 2: Lecture 13 Forebrain

Question 1

parts of the diencephalon (4)

Answer 1

Epithalamus: pineal gland
Thalamus: many important functions
Subthalamus: involved with basal ganglia
Hypothalamus: many functions ⇒ autonomic regulation

Question 2

what does the hypothalamus do for functions? (5)

Answer 2

autonomic regulation for:
- Temperature regulation
- Feeding and drinking
- Circadian rhythms
- Aggression and flight
- Sexual activity
–> release hormones into the blood that act on the pituitary gland which dumps stuff into the bloodstream to cause hormonal signals (vasopressin, oxytocin, etc.)

Question 3

pituitary stalk

Answer 3

where the pituitary gland is attached to the hypothalamus

Question 4

What can be seen in the images of the thalamus? (5)

Answer 4

• reticular nucleus
• 3rd ventricle
• inter thalamic adhesion
• corpus callous
• internal capsule

Question 5

thalamic reticular nucleus

Answer 5

the thalamus is surrounded by a thin outer shell of neurons and relays many things

Question 6

the thalamus relays everything but what?

Answer 6

smell

Question 7

internal medullary lamina

Answer 7

sheets of axons running through the middle of the thalamus
- These separate different thalamic nuclei (groups of neurons)
- divides the thalamus into 3 regions

Question 8

intralaminar nuclei

Answer 8

clusters of neurons in the axons of the internal medullary lamina

Question 9

3 types of nuclei in the thalamus

Answer 9

• specific nuclei
• association nuclei
• nonspecific nuclei

Question 10

specific nuclei

Answer 10

(tract specific) relay specific sensory or motor information to specific regions of cortex ⇒ visual thalamus projects to visual cortex
- Associated with somatosensory or motoneurons in the cerebral cortex
- Relay the information from one point to another

Question 11

Functions of association nuclei

Answer 11

relay information from association thalamus to association cortex ⇒ respond to more than one type of sensory stimulus
- Neurons in the pulvinar nucleus of the thalamus may respond to both visual and auditory stimuli
- Association nuclei project their axons to association cortex in the posterior parietal lobe

Question 12

nonspecific nuclei

Answer 12

have diffuse (all over) projections to cortex ⇒ respond to 1+ sensory stimuli
- Thalamic neurons in these regions may also respond to more than one stimulus
- They project widely throughout the cerebral cortex not just to association cortex and include the intralaminar nuclei

Question 13

inter thalamic adhesion

Answer 13

where the two thalamus halves touch, nothing goes on here

Question 14

what surrounds the outside of the thalamus

Answer 14

reticular nucleus

Question 15

what runs like a band through the middle (white band)

Answer 15

Internal medullary lamina

Question 16

what does the medial geniculate nucleus do?

Answer 16

relay hearing from the thalamus

Question 17

what does the lateral geniculate nucleus do?

Answer 17

relay vision from the thalamus

Question 18

what does the anterior and ventral lateral nucleus do?

Answer 18

relay motor from the thalamus

Question 19

what does the ventral posterior medial nuclei do?

Answer 19

touch and pain
- also relays head and face information from the thalamus

Question 20

what does the ventral posterior lateral nuclei do?

Answer 20

relay information from the thalamus to the rest of the body

Question 21

relay nuclei

Answer 21

send axons to the cerebral cortex
- projections are ipsilateral (same side)

Question 22

where do the visual, motor, and associated thalamus go?

Answer 22

go to the visual, motor, and associated cortex

Question 23

what are the association thalamus regions?

Answer 23

medial dorsal nucleus and pulvinar nucleus

Question 24

medial dorsal nucleus

Answer 24

prefrontal association cortex

Question 25

pulvinar nucleus

Answer 25

parietal-occipital temporal association cortex

Question 26

what are the nonspecific nuclei of the thalamus

Answer 26

reticular nucleus and intralaminar nuclei

Question 27

what is the nucleus and output related to the hypothalamus and hippocampus?

Answer 27

anterior nucleus and cingulate cortex (limbic)

Question 28

what is the nucleus and output related to the cerebellum?

Answer 28

ventral lateral nucleus and motor cortex

Question 29

what is the nucleus and output related to the retina?

Answer 29

lateral geniculate nucleus and visual cortex

Question 30

what is the nucleus and output related to the somatosensory and visceral sensory?

Answer 30

ventral posterior nucleus (lateral and medial) and somatosensory cortex and visceral cortex

Question 31

what is the nucleus and output related to the inferior colliculus?

Answer 31

medial geniculate nucleus and auditory cortex

Question 32

what is the nucleus and output related to the cortex and other areas?

Answer 32

other nuclei and association cortex

Question 33

what does the thalamus do?

Answer 33

the flow of information from the thalamus to cortex is gated by inputs from the cortex and the brain stem reticular activating system via the reticular nucleus of the thalamus - inhibits neuron output

Question 34

what is the result of gating thalamic output?

Answer 34

sleep and concentration

Question 35

internal capsule

Answer 35

superhighway of axons entering and exiting the cortex relaying information ascending from the thalamus and descending from the cortex

Question 36

what axons keep descending from the thalamus?

Answer 36

corticospinal tract and cortical neurons for fine motor control

Question 37

what is the telencephalon made up of? (3)

Answer 37

neocortex, limbic and olfactory cortex, and the basal ganglia

Question 38

what structures are in the cerebral cortex?

Answer 38

the allocortex (3-5 cell layers that includes the hippocampus) and the neocortex which is 6 cell layers

Question 39

how does the wiring of the neocortex work? (4)

Answer 39

- Thalamus projects to layer IV - Layer IV projects to II and III which interconnect with other cortical areas (info from thalamus) - Layer V projects to brainstem and spinal cord ⇒ fine motor movements - Layer VI projects back to thalamus ⇒ input from cerebral cortex back to the thalamus as well

Question 40

what are the primary cortical regions (2)

Answer 40

primary sensory cortex and primary motor cortex

Question 41

primary sensory cortex

Answer 41

cortex that is innervated by specific thalamic relay nuclei for the same sense ⇒ first stop in cerebral cortex from thalamus which can get processed further - includes vision and somatosensation

Question 42

primary motor cortex

Answer 42

cortex that innervates spinal cord or brainstem and controls motoneurons

Question 43

what input goes in to the association and what goes out?

Answer 43

in: visual, somatosensory, auditory cortexes out: speech, writing, functional correlation, sensory motor coordination

Question 44

cerebral commissures

Answer 44

A region of cortex on one side of the brian communicates with the same region on the other side - discrete bundle of axons that cross the midline

Question 45

what are the 2 cerebral cortex commissures?

Answer 45

1. corpus callous 2. anterior commissure for olfactory system and related information (all vertebrates)

Question 46

what happens when there are lesions of the corpus callosum

Answer 46

epilepsy via uncontrolled contraction and possibly full body seizure - CC can be cut but then you have "2 minds"

Question 47

what is part of the limbic and olfactory cortical areas? (3)

Answer 47

- hippocampus - amygdala - fornix

Question 48

hippocampus location

Answer 48

in the temporal lobe inside the parahippocampal gyrus

Question 49

amygdala

Answer 49

in the anterior temporal lobe, just rostral to the hippocampus - Involved in conditioned fear responses

Question 50

fornix

Answer 50

from the hippocampus to mammillary bodies of the hypothalamus - tract of the limbic system

Question 51

basal ganglia

Answer 51

group of nuclei in the midbrain, diencephalon, and basal region of the telencephalon with roles in the motor system and motivation - includes drug use

Question 52

major nuclei of the basal ganglia (4)

Answer 52

1. striatum (telencephalon) 2. globus pallidus (telencephalon) 3. sub thalamic nucleus (diencephalon) 4. substantia nigra (midbrain)

Question 53

striatum (3 nuclei)

Answer 53

Caudate nucleus Putamen Nucleus accumbens

Question 54

globules pallidus

Answer 54

part of the basal ganglia

Question 55

sub thalamic nucleus

Answer 55

part of the diencephalon positioned ventral to the thalamus and dorsolateral to the mammillary bodies - motor control and movement