Lecture 1: Human Brain Flashcards
Name some important sulci
Central Sulcus Lateral Sulcus Parieto-occipital sulcus
What landmarks mark the Frontal Lobe?
Central Sulcus Lateral Sulcus
What landmarks mark the Occipital Lobe?
Parieto-occipital sulcus Preoccipital notch
What landmarks mark the Temporal Lobe?
Preoccipital Notch
Latearl Fissure
What landmarks mark the Parietal lobe?
Central Sulcus Parieto-occipital sulcus
What structures are found in the frontal lobe?
1) Superior frontal gyrus 2) Middle frontal gyrus 3) Inferior frontal gyrus 4) Broca’s area 5) Precentral Gyrus
What structures are found in the Parietal lobe?
1) Postcentral gyrus 2) Supramarginal gyrus (reading) 3) Angular gyrus (writing) 4) Superior parietal lobule
What structures are found in the Temporal lobe?
1) Superior Temporal gyrus 2) Middle Temporal gyrus 3) Inferior Temporal gyrus 4) Wernicke’s Area 5) Primary auditory cortex
What structures are found in the Occipital lobe?
1) Primary visual cortex 2) Secondary visual cortec
What is the Frontal association cortex involved in?
1) Intelligence 2) Personality 3) Behaviour 4) Cognitive Function 5) Mood
What is the Parietal association cortex involved in?
1) Spatial
2) 3D recognition- particuarily faces, shapes, concepts, abstract perception
3) (right side) music, non-verbal music interpretation, nuance
What is the Temporal association cortex involved in?
1) Memory 2) Mood 3) Aggression 4) Intelligence
What is the name of the huge gyrus that can be seen in the medial aspect of the brain?
Cingulate Gyrus
What is under the cingluate gyrus?
Corpus Callosum (white matter bundle- takes info from 1 hemisphere to another).
What makes up the Hindbrain?
Cerebellum,
Pons,
Medulla oblongata.
Can you see all 4 lobes of the brain in the medial aspect of the brain?
Yes
Describe the precentral gyrus (function and features of the neurons)
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.)
What informs the precentral gyrus on what nerves to activate and therefore muscles to move?
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
Where is the Broca’s area found?
In the motor planning area (in the middle frontal gyrus)
Where is the Wernicke’s area found?
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
What is the primary auditory cortex involved in?
Break down according to pitch (do not process this)
Different tones are recorded by different parts of the auditory cortex.
Describe the 2 functions of the Wernicke’s area
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)
Someone asks you what the time is. What are the brain processes involved in answering this question?
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
What connects Wernike’s area iwth the Broca’s area?
arcuate fasciculus
(fasciculus just means bundle of white matter)
What happens in your brain, when you want to read or write?
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.
If someone cannot interpret sounds, what disorder do they have?
Wernikes aphasia or sensory aphasia
If someone can understand correctly, but has difficulty answering questions, what sort of disorder would this be?
Broca’s/ Motor aphasia
How can you tell if someone has Broca’s or Wernike’s aphasia?
Get them to make a written response.
If they can answer correctly via writing: Broca’s aphasia
If they cannot: Wernike’s aphasia
What is it called when the arcuate fasiculus is damaged?
Connectional Aphasia
They will make an inappropriate response. They can understand and speak perfectly fine.
Primary Visual cortex is mainly made up of……
Sensory nerves.
What type of consequences would you observe if there were lesions in these 3 areas?
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.
What are some differences between sensory and motor homuncular map?
1) Cannot control teeth can sense pain in teeth
2) Lips are larger in the somatosensory compared with motor
What are Association fibres?
Connect 2 parts of the same hemisphere
What are the name of fibres that connect two parts of the same hemisphere?
Association fibres
What are Commisural fibres?
Connect the 2 hemispheres
What are the names of fibres that connect 2 hemispheres?
Commisural fibres
What are Projection fibres>
Project from the brain to the spinal cord
What are the names of the fibres that go from the brain to the spinal cord?
Projection fibres
Give an example of association, commisural and projection fibres
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.
Is the grey matter on the outside or inside of the brain?
Outside.
What makes up the grey matter?
- neuronal cell bodies,
- neuropil glial cells (astrocytes and oligodendrocytes),
- synapses,
- capillaries.
What is neocortex?
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.
What is Allocortex?
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.
Describe the structure of a typical neocortex
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.
What are the sizes of External pyramidal cells?
(3rd layer)
~10-40 micrometer
What layers of the neocortex are input layers?
Largely layer 2 and 4
What layers of the neocortex are output layers?
Layers 3 and 5
What is the difference between homotypical and heterotypical neocortex?
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)
What are the sizes of neurons in the External pyramidal layer?
60-120 micrometers.
Where are homotypical neocortex found?
1) Homotypical- (most)
1) association cortices: prefrontal, parietal association and temporal)
Where are the agranular heterotypical neurons found?
1) Precentral gyrus
2) Primary motor cortex
Where are the Granular Heterotypical cells often found?
1) Primary sensory cortices (e.g. primary somatosensory cortex)
2) Primary visual cortex
3) Primary auditory cortex
