Neuroanatomy Laterization And Localization

Question 1

How does the skull protect the brain?

Answer 1

bony outer layer, suit of armour, first line of defence, protect direct force of mechanical insult, against potential damage or intrusion

Question 2

How does the CSF protect brain?

Answer 2

shock absorber, reduce impact of whatever force makes it through the brain itself. Increases buoyancy, decreases pressure of brain stem, cells of nervous system receive nutrients from CSF

Question 3

How does the Meninges protect brain?

and what are the 3 separate sheaths?

Answer 3

protective covering surrounding tissue of brain
3 separate sheaths
1) PIA MATER
2) ARACHNOID MEMBRANE
3) DURA MATER
space between Pia mater and arachnoid = SUB ARACHNOID SPACE

Question 4

How does the blood-brain barrier protect the brain?

Answer 4

• supply brain and spinal cord with blood
• allow only some substances to pass in/ out of brain
• capillaries of brain don’t contain GAPS unlike capillary walls elsewhere in the body = selectively permeable

Question 5

Exception to blood brain barrier?

Answer 5

Area Prostrema: controls vomitting reflex

-allows brain to find toxic substances in blood so body can rid them through vomiting any substance in stomach

Question 6

What is the cortex made up of? (Latin word bark)

Answer 6

-resembles a shelled walnut with bumps and crevices
-made up of Fissures which are deep crevices and Sulci
if they are shallow
-bumps are called gyri
these serve as divisions of the cortex

Question 7

what are the primary FISSURES?

Answer 7

1) Longitudinal fissures: separates left and right hemi
2) Central Fissures: separates frontal lobe from parietal lobe of each hemi
3) Lateral Fissures: separates the temporal lobe from frontal and parietal lobe of each hemi

Question 8

Primary GYRI?

Answer 8

1: Pre and post central Gyri: divide the central fissure (pre in front, and post behind)

Question 9

What are the 4 primary Lobes and their functions?

Answer 9

1) Frontal Lobes: motor function and personality
2) Parietal Lobes: somatosensation
3) Temporal Lobes: audition and memory
4) Occipital Lobes: vision

Question 10

What 2 axons map projection areas?

Answer 10

AFFERENT Axons: APPROACH central nervous system from sensory systems into the cortex
EFFERENT Axons: EXIT the CNS from the cortex as they project to the motor systems of brainstem and spinal cord

Question 11

Afferents role:

Answer 11

carry info from joints and sensory system, skeletal muscles and vice-versa (body organs) towards the CNS
-provide CNS with info about body environment

Question 12

Efferents role:

Answer 12

carry info from CNS toward the skeletal muscles and vice versa. Enabling the organism to behave in accordance with the incoming info.

Question 13

What are the 3 projection areas?

Answer 13

1. Primary Area
2. Secondary Area
3. Tertiary or Association Area

Question 14

Primary sensory projections: what are they arising from and where do they go?

Primary motor projections: what are they arising from and where do they go?

Answer 14

Primary sensory projections= eye, ear, and somatosensory systems
go to: Primary projection areas of corresponding lobes of cortex (occipital, temporal, and parietal)

Primary motor projections= arise from primary motor cortex
go to: spinal cord where connections are made with other neurons that go on to innervate the skeletal muscles of the body

Question 15

DISTRIBUTED FUNCTION

Answer 15

The observation that some behavioural and psychological functions, particularly complex cognitive functions, require collective input from more than one brain structure to execute.

Question 16

What are secondary and tertiary areas?

Answer 16

These are adjacent areas that primary areas receive info from. They also appear to have a role in further analysis, integration, and association from the primary areas.

Question 17

Motor Homunculus

and Sensory Homunculus

Answer 17

1) electrical stimulation of the primary motor cortex reveals a complete motor representation of the body on the precentral gyrus
2) electrical stimulation of primary somatosensory cortex reveals a complete somatosensory representation of the body on the postcentral gyrus which is referred to as the sensory homunculus

Question 18

what do both the primary cortex and the primary somatosensory cortex have in common?

Answer 18

they devote the largest amount of physical space to those areas of the body with greatest sensitivity and those that require the most precise and complex muscular control

ex/ face and hands are very sensitive to touch

Question 19

Cerebral Laterality

Answer 19

• There’s a certain amount of specialization regarding the roll of each hemisphere for different psychological and motor functions, and it is not equal.
• left and right hemi specialized with repect to their cognitive and behavioural functions

Question 20

Longitudinal Fissure

Answer 20

divides the brain in two halves, called left and right cerebral hemi

Question 21

Corpus callosum

Answer 21

a strip of tissue that facillitates communication between hemispheres
-neural signals pass back and forth

Question 22

Role of Left Hemisphere

Role of Right Hemisphere

Answer 22

Left Hemisphere- more involved in langauge tasks, reading and pseaking

Right Hemipshere- more involved in processing and recognition of emotion

Question 23

The division of labour between right and left brained

Answer 23

• origin of colloqualism about whether one is “left or right brained”
• left brain strengths =academic and scientific endevours like writing and math
• right brain strengths= intuitive and arts and fantasy

Question 24

Define Contralateral organization and the exception

Answer 24

• the organization of the brain and body, such that sensory and motor information to and from the left side of the body is primarly processed by the right side of the brain and vice versa
• ex/ visual input received by sensory field (right side) is processed by the opposite hemisphere (left) and then sends information to right side via corpus callosum

*one exception is for the sense OLFACATION which projects ipsilaterally (ipsi=same) into our frontal lobes. This is like much like the motor organization of our bodies
and eyes sensory info arrives at both sensory fields simultaneously

Question 25

What does the forebrain contain?

Answer 25

TELENCEPHALON & DIENCEPHALON

• higher cognitive functioning
• limbic system pathways thought to be affected in schizophrenia
• in proximity of olfactory structures
• Basal ganglia are affected in PARKINSONS Disease
• neurotransmitter dopamine is received by basal ganglia and helps facilitate voluntary movements

Question 26

what is a split brain patient?

Answer 26

A patient whose corpus callosum was severed, and due to this the left and right hemispheres are unable to interact with eachother. In experiements done where image is shown, but cannot speak what the object is due to lack of knowledge being transferred to activate the opposite hemisphere.

Question 27

Localization Function

Answer 27

the observation that particular functions are mediated by specific structures in the brain

Question 28

The telencephalic Structures:

Answer 28

1) cerebral cortex: contsins 4 lobes
2) -Limbic system: amygdala, hippocampus, fornix, cingulate gyrus, septum, mammillary bodes
- plays a role in motivation, memory, emotion, memory and learning, and is composed of several smaller interconnected structures
3) basal ganglia: contains the caudate nucleus, putamen, globus pallidus
- have a role in controlling complex voluntary movements
4) the corpus callosum (largest of the hemispheric commissures)

Question 29

Diencephalic Structures:

Answer 29

1) Thalmus: A collection of nuclei some which receive sensory input from sensory sytems
- LGN Lateral geniculate neclues= receives from visual
- MGN medial geniculate nucles =receives from auditory
- VPN ventral posterior nuclei= receives from somatosensory
- preform a relay/orgnization function between input and output of cortex

2) Hypothalmus: controls the ANS and Endocrine System
and organizes motivation behaviours (4 F’s fleeing, fighting, feeding, and reproduction)
produces hormones that stimulate primary gland to secrete hormones and control endocrine system

Question 30

MidiBrain

Answer 30

contains the Mesencephalon
1) tectum (on the dorsal surface) contains superior colliculi (vision) and inferior colliculi (audition)
2) tegmentum (on the ventral surface)
contains the reticular formation (consits approx. 100 v small nuclei with variety of rolls ex/ sleep, arousal, muscle tone, movement, various cadiac, circulatory, and respiratory reflexes and runs through the mid brain and the hindibrain
-periadqueductal gray matter = movement and pain
-red nucleus (motor coordination) and substania nigra (movement)

Question 31

Hindibrain

Answer 31

contains Metencephalon and Myelencephalon

• contains structures VITAL to survival
• brain damage and tumors here are often fatal

Question 32

Metencephalic structures

Answer 32

1. Pons: contains a number of tracts connecting the brain and spinal cord (ascending and descending tracts) involved in coordination
2. Cerebellum: sensory motor structure that regulates movement and balance, motor movement related to memory

Question 33

Myelencephalic structures:

Answer 33

1. Medulla: controlls vegative functions like breathing
2. Reticular formation: runs through the midibrain as well as hindibrain, consists of many nuclei controlling sleep, arousal, circulatory and respiratory reflexes, attention
   - COMAS often result from damage here
   - DRUGS such as opiates, cocaine and amphetamines have action in these areas and overdose would be fatal, unlike some drugs such as marijuana dont have action here