Lecture 1: Human Brain

Question 1

Name some important sulci

Answer 1

Central Sulcus Lateral Sulcus Parieto-occipital sulcus

Question 2

What landmarks mark the Frontal Lobe?

Answer 2

Central Sulcus Lateral Sulcus

Question 3

What landmarks mark the Occipital Lobe?

Answer 3

Parieto-occipital sulcus Preoccipital notch

Question 4

What landmarks mark the Temporal Lobe?

Answer 4

Preoccipital Notch

Latearl Fissure

Question 5

What landmarks mark the Parietal lobe?

Answer 5

Central Sulcus Parieto-occipital sulcus

Question 6

What structures are found in the frontal lobe?

Answer 6

1) Superior frontal gyrus 2) Middle frontal gyrus 3) Inferior frontal gyrus 4) Broca’s area 5) Precentral Gyrus

Question 7

What structures are found in the Parietal lobe?

Answer 7

1) Postcentral gyrus 2) Supramarginal gyrus (reading) 3) Angular gyrus (writing) 4) Superior parietal lobule

Question 8

What structures are found in the Temporal lobe?

Answer 8

1) Superior Temporal gyrus 2) Middle Temporal gyrus 3) Inferior Temporal gyrus 4) Wernicke’s Area 5) Primary auditory cortex

Question 9

What structures are found in the Occipital lobe?

Answer 9

1) Primary visual cortex 2) Secondary visual cortec

Question 10

What is the Frontal association cortex involved in?

Answer 10

1) Intelligence 2) Personality 3) Behaviour 4) Cognitive Function 5) Mood

Question 11

What is the Parietal association cortex involved in?

Answer 11

1) Spatial
2) 3D recognition- particuarily faces, shapes, concepts, abstract perception
3) (right side) music, non-verbal music interpretation, nuance

Question 12

What is the Temporal association cortex involved in?

Answer 12

1) Memory 2) Mood 3) Aggression 4) Intelligence

Question 13

What is the name of the huge gyrus that can be seen in the medial aspect of the brain?

Answer 13

Cingulate Gyrus

Question 14

What is under the cingluate gyrus?

Answer 14

Corpus Callosum (white matter bundle- takes info from 1 hemisphere to another).

Question 15

What makes up the Hindbrain?

Answer 15

Cerebellum,

Pons,

Medulla oblongata.

Question 16

Can you see all 4 lobes of the brain in the medial aspect of the brain?

Answer 16

Yes

Question 17

Describe the precentral gyrus (function and features of the neurons)

Answer 17

Contain all of the fibres that act as the relay point that activate muscle

Primary Motor Cortex

Contains large pyramid shaped neurons (the size is proportional to the distance they have to travel)

The topographical representation of the homunculus is arranged in an anatomical fashion (e.g. face then eyes then hands then torso etc.)

Question 18

What informs the precentral gyrus on what nerves to activate and therefore muscles to move?

Answer 18

Motor Planning area.

The Broca’s area (motor planning area around speech) can be found in the motor planning area, next to the facial area in the primary motor cortex

Question 19

Where is the Broca’s area found?

Answer 19

In the motor planning area (in the middle frontal gyrus)

Question 20

Where is the Wernicke’s area found?

Answer 20

Superior temporal gyrus, next to the primary auditory cortex

The Wernicke’s area is located in the temporal lobe on the left side of the brain and is responsible for the comprehension of speech

Question 21

What is the primary auditory cortex involved in?

Answer 21

Break down according to pitch (do not process this)

Different tones are recorded by different parts of the auditory cortex.

Question 22

Describe the 2 functions of the Wernicke’s area

Answer 22

The Wernicke’s area is located in the temporal lobe on the left side of the brain and is responsible for the comprehension of speech

Wernike’s area also suppresses non-relevant sounds (e.g. pen scratching paper)

Question 23

Someone asks you what the time is. What are the brain processes involved in answering this question?

Answer 23

1) Primary Auditory cortex recognises sound
2) Wernike’s area processes the question (+ suppresses irrelevant noises)
3) Information is transferred via the arcuate fasciculus
4) Broca’s area processes what to say
5) Precentral gyrus/primary motor cortex innervates the nerves to innervate the right muscles to answer the question

Question 24

What connects Wernike’s area iwth the Broca’s area?

Answer 24

arcuate fasciculus

(fasciculus just means bundle of white matter)

Question 25

What happens in your brain, when you want to read or write?

Answer 25

Fasiculi connect the supramarginal gyrus (reading) activate the planning areas in the eye and hand motor planning areas. This causes activation of the primary motor cortex areas associated with these areas. Fasiculi also connect the supramarginal gyrus with the Wernike's area to process what you're reading.

Question 26

If someone cannot interpret sounds, what disorder do they have?

Answer 26

Wernikes aphasia or sensory aphasia

Question 27

If someone can understand correctly, but has difficulty answering questions, what sort of disorder would this be?

Answer 27

Broca's/ Motor aphasia

Question 28

How can you tell if someone has Broca's or Wernike's aphasia?

Answer 28

Get them to make a written response. If they can answer correctly via writing: Broca's aphasia If they cannot: Wernike's aphasia

Question 29

What is it called when the arcuate fasiculus is damaged?

Answer 29

Connectional Aphasia They will make an inappropriate response. They can understand and speak perfectly fine.

Question 30

Primary Visual cortex is mainly made up of......

Answer 30

Sensory nerves.

Question 31

What type of consequences would you observe if there were lesions in these 3 areas?

Answer 31

Green: Loss of sensation (Probably facial region on the right side of the face) Purple: Wernike's aphasia Red: Challenge in behaviour, personality, cognition etc.

Question 32

What are some differences between sensory and motor homuncular map?

Answer 32

1) Cannot control teeth can sense pain in teeth 2) Lips are larger in the somatosensory compared with motor

Question 33

What are Association fibres?

Answer 33

Connect 2 parts of the same hemisphere

Question 34

What are the name of fibres that connect two parts of the same hemisphere?

Answer 34

Association fibres

Question 35

What are Commisural fibres?

Answer 35

Connect the 2 hemispheres

Question 36

What are the names of fibres that connect 2 hemispheres?

Answer 36

Commisural fibres

Question 37

What are Projection fibres\>

Answer 37

Project from the brain to the spinal cord

Question 38

What are the names of the fibres that go from the brain to the spinal cord?

Answer 38

Projection fibres

Question 39

Give an example of association, commisural and projection fibres

Answer 39

Association (connects 2 parts of the same hemisphere): Arcuate fasiculus Commisural (Connect 2 hemispheres): Anterior commisure, Corpus callosum Projection (Project from the brain to the spinal cord): Nerves that go from brain to spinal cord.

Question 40

Is the grey matter on the outside or inside of the brain?

Answer 40

Outside.

Question 41

What makes up the grey matter?

Answer 41

* neuronal cell bodies, * neuropil glial cells (astrocytes and oligodendrocytes), * synapses, * capillaries.

Question 42

What is neocortex?

Answer 42

It is the top layer of most of cerebral hemispheres, It is 2-4 mm thick, and made up of six layers, labelled I to VI (with VI being the innermost and I being the outermost). It is involved in higher functions such as sensory perception, generation of motor commands, spatial reasoning, conscious thought, and in humans, language. The neocortex consists of grey matter surrounding the deeper white matter of the cerebrum.

Question 43

What is Allocortex?

Answer 43

The allocortex (also known as heterogenetic cortex) is one of the two types of cerebral cortex, the other being the neocortex. It is characterized by having just three or four celllayers, in contrast with the six layers of the neocortex, and takes up a much smaller area than the neocortex. There are three subtypes of allocortex: the paleocortex, the archicortex, and the periallocortex – a transitional zone between the neocortex and the allocortex The specific regions of the brain usually described as belonging to the allocortex are the olfactory system, and the hippocampus.

Question 44

Describe the structure of a typical neocortex

Answer 44

Layer 1: Molecular (lots of small fibres, no speciality. It was significant during development) Layer 2: External granular (Sensory input from other areas of the brain) Layer 3: External pyramidal (Sending info to other ares of the cortex) Layer 4: Internal Granular (Receive info from the periphery) Layer 5: Internal pyramidal layer (Motor neurons that form the pyramidal tract- upper motor neurons)= Betz cells Layer 6: Multiform layer (Mixture of all the cells) In the upper layers, the input and output of info is within the brain and in the lower layers, the input and output of info to the rest of the body.

Question 45

What are the sizes of External pyramidal cells?

Answer 45

(3rd layer) ~10-40 micrometer

Question 46

What layers of the neocortex are input layers?

Answer 46

Largely layer 2 and 4

Question 47

What layers of the neocortex are output layers?

Answer 47

Layers 3 and 5

Question 49

What is the difference between homotypical and heterotypical neocortex?

Answer 49

1) Homotypical- (most- association cortex: prefrontal, parietal association and temporal) 2) Heterotypical- rare. 2a) Agranular - pyramidal cells predominate (precentral gyrus and the primary motor cortex) 2b) Granular- granule cells predominate (e.g. primary snsory cortices, primary visual cortex, primary auditory cortex)

Question 50

What are the sizes of neurons in the External pyramidal layer?

Answer 50

60-120 micrometers.

Question 51

Where are homotypical neocortex found?

Answer 51

1) Homotypical- (most) 1) association cortices: prefrontal, parietal association and temporal)

Question 52

Where are the agranular heterotypical neurons found?

Answer 52

1) Precentral gyrus 2) Primary motor cortex

Question 53

Where are the Granular Heterotypical cells often found?

Answer 53

1) Primary sensory cortices (e.g. primary somatosensory cortex) 2) Primary visual cortex 3) Primary auditory cortex