4. Forebrain

Question 1

forebrain: define

Answer 1

refers to cerebellar hemispheres & diencephalon

(aka prosencephalon)

Question 2

what are the 3 components in the diencephalon?

Answer 2

• thalamus
• hypothalamus
• epithalamus

Question 3

thalamus: function

Answer 3

• major relay for sensory information to the cortex (except olfaction) & between cortical structures
• “egg shaped” bunch of nuclei; many discrete nuclei, diff’t nuclei receive diff’t modality information
• part of diencephalon

Question 4

hypothalamus: function

Answer 4

regulates homeostasis and influences hormone release

Question 5

epithalamus: function

Answer 5

influences sleep and wakefulness thru pineal gland

(posterior aspect of diencephalon)

Question 6

what sensory info does NOT pass through thalamus?

Answer 6

The olfactory nerve (CN 1) travels directly to the frontal lobe through the cribriform plate

• this is the only sense that does not travel to the thalamus before accessing the forebrain.

Question 7

thalamus:

processes involved

Answer 7

1. perception
2. timing
3. attention
4. alertness
5. movement
6. awareness
7. consciousness

Question 8

how are thalamic nuclei organized/arraged?

Answer 8

in 5 diff’t groups

1. anterior
2. medial
3. ventral
4. lateral
5. posterior

Question 9

Cranial nerve 1:

1. key characteristics/actions
2. sensory/motor
3. innervates…
4. clinical sign

Answer 9

1. only sensory info that goes directly to nuclei in cortex (not thru thalamus)
2. SENSORY ONLY
3. inn. nasal mucosa to contribute to olfaction/sense of smell
4. CC: impaired sense of smell

Question 10

pathway of sensory info from olfaction

Answer 10

olfactory nerves in nose –> through cribriform plate –>

olfactory bulb –> olfactory tract –> nuclei in cortex

Question 11

cranial nerve 2

1. key characteristics/actions
2. sensory/motor
3. innervates…
4. clinical sign

Answer 11

1. optic nerve; originates in RETINA
2. SENSORY ONLY
3. contributes to vision
4. CC: blindness in all or part of visual field

Question 12

course of optic nerve

Answer 12

retina, where optic nerve originates –>

through optic chiasm –>

optic tract –>

thalamus?

Question 13

optic chiasm

Answer 13

x-shaped structure where some fibers of optic nerve cross and innervate structures on contralateral side; some continue on and innervate ipsilateral side

Question 14

hypothalamus: define

Answer 14

group of small nuclei

rostral to brainstem

Question 15

hypothalamus: how does it regulate homeostasis?

Answer 15

1. influences pituitary gland
2. regulates food/water intake
3. regulates sleep/wake cycle
4. regulates Parasymp and symp nervous systems

Question 16

KEY CONCEPT: hypothalamus has several discrete nuclei involved in homeostatic functions

Answer 16

many discrete nuclei involved in homeostatic functions

Question 17

what is key role of each THALAMIC NUCLEI?

1. anterior
2. medial
3. ventral
4. lateral
5. posterior

Answer 17

1. anterior - part of limbic system; memory and emotion
2. medial - emotional output to prefrontal cortex; awareness of emotions
3. ventral - somesthetic output to postcentral gyrus –> signals from cerebellum and basal nuclei to motor areas of cortex
4. lateral - somesthetic output to assoc. areas of cortex; contributes to emotional function of limbic system
5. posterior - relay of visual signals to occipital lobe and auditory signals to temporal lobe

Question 18

location of hypothalamus

Answer 18

extends anteriorly from the optic chiasm, to the mamillary bodies posteriorly

Question 19

what makes up the epithalamus?

Answer 19

• habenula
• pineal gland

Question 20

pineal gland: function

Answer 20

posterior aspect of diencephalon that contains the pineal gland

gland produces melatonin –> regulates wakefulness

(very hard to dissect, but posterior to THALAMUS)

Question 21

cerebral hemispheres

Answer 21

largest part of brain; w/ structures duplicated in each hemisphere

• disctinct grooves and folds called sulci and gyri
• divided into lobes, w/ some distinct functions

Question 22

purpose of folds and grooves (gyri & sulci) in brain?

Answer 22

to increase surface area –> fitting more into less “Real estate”

Question 23

gray matter is found where in cerebral hemisphere?

Answer 23

found in cerebral cortex & deep nuclei

Question 24

white matter is found where in cerebral hemispheres?

Answer 24

much of volume of cerebral hemisphere is white matter

• 3 main types of fibers
• internal capsule

Question 25

3 types of white matter fibers, & what they do

Answer 25

* **projection fibers** - *sensory connections from the brainstem, and spinal cord and motor connections to brainstem and spinal cord* * **association fibers** - *connections w/in lobes or from one lobe to another* * **commissural fibers** - *connections between hemispheres*

Question 26

four lobes and general functions

Answer 26

1. FRONTAL (primary motor cortex) * cognition, decision-making, judgement, voluntary movement 2. PARIETAL (somatosensory cortex) * touch, proprioception 3. OCCIPITAL (primary visual cortex) * vision 4. TEMPORAL (amygdala, hippocampus) * auditory, olfactory, fear response, learning

Question 27

frontal lobe (gross)

Answer 27

bordered by **central sulcus**, and **lateral fissure** are both folds

Question 28

pre-central gyrus

Answer 28

part of frontal lobe; contains primary motor cortex fxn: area controls execution of movement

Question 29

primary motor cortex - "motor map"

Answer 29

* distinct areas of primary motor cortex control movement in specific parts of the body * notice more real estate is given to areas w/ more moving parts * (accounts for greater amount of the motor cortex)

Question 30

parietal lobe: boundaries

Answer 30

* bordered by the central sulcus, and lateral fissure * the posterior border is less well-defined

Question 31

parieto-occipital sulcus separates which 2 lobes?

Answer 31

between (1) **parietal**, and (2) **occipital** lobe

Question 32

where is the **post-central gyrus** located, and function

Answer 32

* bordered by **central sulcus** and **lateral fissure** * function: main receptive area for the sense of touch and contains a somatosensory "map" (homunculus) * the map shows areas that require a more sensitive touch gradient receive more real estate

Question 33

occipital lobe: borders

Answer 33

* bordered by the preoccipital notch * contains primary visual cortex; primary visual cortex processes vidual information and creates a map of the visual field

Question 34

occipital lobe: functions

Answer 34

contains primary visual cortex; which processes visual information & creates map of visual field

Question 35

Temporal lobe: borders and function

Answer 35

* bordered by **lateral fissure** and the **pre-occipital notch** * **i**nvolved in **audition** * deeper in the temporal lobe is vertically-oriented gyri which comprise the insula (pain and taste fxns)

Question 36

which 4 structures make up the DEEP NUCLEI?

Answer 36

* globus pallidus * caudate * putamen * amygdala

Question 37

which of the deep cerebral nuclei are considered **BASAL nuclei?**

Answer 37

* caudate * putamen * globus pallidus

Question 38

basal nuclei: function

Answer 38

invovled w/ onset and cessation of intentional movements; esp repetitive ones

Question 39

internal capsule: definition and functions

Answer 39

1. large fiber tract amid the deep cerebellar nuclei 2. Incl. axons relaying sensory info from thalamus to cerebral cortex, and axons relaying motor signals to motor neurons from the cerebral cortex to lower neurons

Question 40

location of deep cerebral nuclei and internap capsule - gross anatomy

Answer 40