Cerebral Cortex 2

Question 1

Describe the larger structure of the Cerebral Cortex?

Answer 1

Covers surface of the brain and contains grey matter ( deep nuclei )

Highly folded gyri + sulci

Organised into lobes

Question 2

Describe the microscopic organisation of the cerebral cortex?

Answer 2

Organised into layers + columns:

Layers:
I - Molecular
II - External granular layer
III - External pyramidal layer
IV - Internal granular layer
V- internal pyramidal layer
VI-multiform layer

Question 3

What is cytoarchitecture?

Answer 3

Cell size, spacing or packing density.

Many areas are shown to relate to function

Question 4

What are the functions of the 4 lobes?

Answer 4

Frontal : motor function
language
cognitive functions
attention
memory

Parietal: touch pain, sensory aspect of language, spatial orientation and self perception

Occipital:
visual info

Temporal lobe:
auditory info, emotion and memory

Question 5

Limbic lobe?

Answer 5

Amygdala, hippocampus, mamillary body, cingulate gyrus

Question 6

Insular cortex?

Answer 6

deep within lateral fissure
Concerened with visceral sensations, autonomic control, interoception, auditory processing, visual vestibular integration

Question 7

What do white matter tracts do?

Answer 7

Connect cortical areas

3 types of fibres make up the white matter tract

Question 8

What do association fibres do?

What subsplits are there? (4)

Answer 8

Connect areas within the same hemisphere

the superior longitudinal fasciculus connects frontal and occipital lobes

Arcuate Fasciculus - connects frontal and temporal lobes

Inferior Longitudinal Fasciculus - connects temporal and occipital lobes

Uncinate Fasciculus - connects anterior frontal and temporal lobes

Question 9

What do commissural fibres do?

What subsplits are there? (2)

Answer 9

Connect homologous structure in left and right hemispheres

Corpus callosum
+Anterior commissure

Question 10

What do projection fibres do?

Answer 10

Connect cortex with lower brain structures

Have afferent fibres towards cortex

Efferent away from cortex

deeper to cortex radiate as the corona radiata

converge through internal capsule between thalamus and basal ganglia

Question 11

What happens when Primary cortices is localised?

Answer 11

The function is predictable
Organised topographically
Symmetry between left and right

• i think this means the somatosensory and motor cortices, if they are stimulated the results are expected and symmetry means along the head the results occur topographically on both sides

Question 12

What happens when secondary/association cortices are localised?

Answer 12

function less predictable
not organised topographically
left-right symmetry weak or absent

Question 13

What three motor areas are found in the frontal lobe?

Answer 13

Primary: controls fine, discrete, precise voluntary movements.
Provides descending signals to execute movements.

Supplementary: Involved in planning complex movements (e.g. internally cued)

Premotor area: involved in planning movements (e.g. externally cued)

Question 14

What areas is the parietal lobe split in to?

Answer 14

Primary somatosensory:
processes somatic sensations arising from receptors in the body (e.g. fine touch, vibration, two-point discrimination, proprioception, pain and temperature.

Somatosensory association
Interpret significance of sensory information, e.g. recognizing an object placed in the hand.
Awareness of self and awareness of personal space

Question 15

How is the occipital lobe split up?

Answer 15

Primary visual:
Processes visual stimuli

Visual association:
Gives meaning and interpretation of visual input

Question 16

How is the temporal lobe split up?

Answer 16

Primary auditory:
processes auditorystimuli

Auditory association:
Gives meaning and interpretation of auditory input

Question 17

What does the prefrontal cortex do?

Answer 17

attention
adhisting social behaviour
planning
personality expression
decision making

( noticeable change in personality if affected )

Question 18

What does the brocas area do?

Answer 18

Production of speech (left side of brain) * know what u want to say but if lesion cannot physcially speak

Question 19

What does the Wernickes area do?

Answer 19

understanding of language (left side of brain) * don’t understand language coming into brain if lesion

Question 20

What happens after a frontal lobe lesion?

Answer 20

Changes in personality, inappropriate behaviour

Question 21

What happens after parietal lobe lesions?

Answer 21

in right hemisphere :

contralateral neglect = lose track of the other side of his body e.g. forget to put left arm and leg into trousers and shirt

and

lack of awareness of self on the left side
Lack of awareness of left side of extrapersonal space

Question 22

What happens after temporal lobe lesions?

Answer 22

Leads to agnosia = inability to recognise + inability to form memories

Question 23

Lesions to Broca’s?

Answer 23

Expressive aphasia – poor production of speech, comprehension intact

Question 24

Lesions to Wernicke’s?

Answer 24

Receptive aphasia – poor comprehension of speech, production is fine

Question 25

Primary Visual cortex lesion?

Answer 25

Blindness in the corresponding part of the visual field

Question 26

Visual association lesion?

Answer 26

Deficts in interpretation of visual information e.g.

prosopagnosia - inability to recognise familar faces or learn new faces ( face blindness )

Question 27

How do PETs work?

Answer 27

Positron emission tomography (PET)

blood flow directly to a brain region

Question 28

How does fMRIs work?

Answer 28

Functional magnetic resonance imaging (fMRI)

amount of blood oxygen in a brain region

Question 29

How does EEGs work?

good for evoked potentials

Answer 29

Electroencephalography (EEG)

Measures electrical signals produces by the brain

Series of waves that reflect sequential activation of neural structures along the somatosenory pathways

Question 30

How does MEGs work?

good for evoked potentials

Answer 30

Magnetoencephalography

Measures magnetic signals produces by the brain

Question 31

How is brain stimulation done?

Answer 31

assessthefunctionalintegrity of neural circuits

Uses electromagnetic induction to stimulate neurons

Transcranial magnetic stimulation (TMS)

Question 32

What is a transcranial direct current stimulation - tDCS ?

Answer 32

Uses low direct current over the scalp to increase or decrease neuronal firing rates

Question 33

What type of imaging is DTI?

Answer 33

Diffusion tensor imaging (DTI)

Based on diffusionof water molecules

Question 34

What is DTI with tractography?

Answer 34

3D reconstruction to assess neural tracts