Cerebral Cortex

Question 1

Layers of brain

Answer 1

Molecular - superficial
External granular 
External pyramidal 
Internal granular 
Internal pyramidal 
Multiform - deep

Question 2

Regions of brain

Answer 2

52
By cytoarchitecture
Brodmann

Question 3

Frontal lobe

Answer 3

Motor function
Language
Cognitive function
Attention
Memory

Question 4

Parietal lobe

Answer 4

Sensation
Sensory of language
Spatial orientation and self perception

Question 5

Occipital lobe

Answer 5

Visual

Question 6

Temporal lobe

Answer 6

Auditory
Emotions
Memories

Question 7

Limbic lobe

Answer 7

Amygdala, hippocampus, mamillary body, cingulate gyrus

Learning, memory, emotion, motivation and reward

Question 8

Insular cortex

Answer 8

Deep within lateral fissure

Visceral sensation, autonomic control, interoception, auditory processing, visual vestibular integration

Question 9

Internal structures

Answer 9

Grey matter - neuronal cell bodies and glial cells

White matter - Myelinated neuronal axons

Question 10

White matter tracts

Answer 10

Connect cortical areas

Association fibres - same hemisphere
Commissural fibres - right and left hemisphere
Projection fibres - Cortex with lower brain structures

Question 11

Association fibres

Answer 11

Superior longitudinal fasciculus - frontal and occipital
Arcuate fasciculus - frontal and temporal
Inferior longitudinal fasciculus - temporal and occipital
Uncinate fasciculus - frontal and temporal

Question 12

Commissural fibres

Answer 12

Corpus callosum - surgically disconnected for intractable or untreatable epilepsy
Anterior commissure

Question 13

Projection fibres

Answer 13

Afferent - toward cortex
Efferent - away from cortex
Radiate as corona radiata deeper to cortex
Converge through internal capsule between thalamus and basal ganaglia

Question 14

Localisation of function

Answer 14

Primary cortices - function predictable, organised topographically, symmetrical
Secondary corices - function less predictable, not organised topographically, not symmetrical

Question 15

Frontal lobe regions

Answer 15

Primary motor cortex - fine, precise, voluntary movement - provide descending signal to execute movements
Supplementary motor cortex - planning complex movements - internally cued
Premotor area - planning externally cued

Question 16

Parietal lobe regions

Answer 16

Primary somatosensory - somatic sensation from receptors in body, fine touch, vibration, pain
Somatosensory association - interpret significance of sensory info, aware of self and space

Question 17

Occipital lobe regions

Answer 17

Primary visual - process visual stimuli

Visual association - interpret visual input

Question 18

Temporal lobe regions

Answer 18

Primary auditory - process auditory stimuli

Auditory association - interpret aduditory input

Question 19

Other areas

Answer 19

Broca’s - produce speech
Wernicke’s - understanding language
Profrontal cortex - attention, social behaviour, decision making

Question 19

Frontal lobe lesions

Answer 19

Changes in personality

Inappropriate behaviour

Question 19

Parietal lobe lesions

Answer 19

e.g. lesion in right hemisphere
Contralateral neglect
Lack of awareness of self on left side
Lack of awareness of left side of extrapersonal space

Question 19

Temporal lobe lesions

Answer 19

Leads to agnosia, inability to recognise

Could not form new memories - anterograde amnesia

Question 20

Lesions to Broca’s or Wernicke’s areas

Answer 20

Broca’s area - Expressive aphasia – poor production of speech, comprehension intact
Wernicke’s area - Receptive aphasia – poor comprehension of speech, production is fine

Question 21

Primary visual cortex lesion

Answer 21

blindness in the corresponding part of the visual field

Question 22

Visual association lesion

Answer 22

deficits in interpretation of visual information e.g. prosopagnosia: inability to recognise familiar faces or learn new faces (face blindness)

Question 23

Assessing cortical function – imaging

Answer 23

Positron emission tomography (PET) - blood flow directly to a brain region Functional magnetic resonance imaging (fMRI) - amount of blood oxygen in a brain region Electroencephalography (EEG) - Measures electrical signals produces by the brain Magnetoencephalography – (MEG) - Measures magnetic signals produces by the brain

Question 24

Assessing cortical function – brain stimulation

Answer 24

Transcranial magnetic stimulation (TMS) - assess the functional integrity of neural circuits, uses electromagnetic induction to stimulate neurons Transcranial direct current stimulation (tDCS) - Uses low direct current over the scalp to increase or decrease neuronal firing rates

Question 25

Assessing structure – imaging

Answer 25

Diffusion tensor imaging (DTI) - Based on diffusion of water molecules DTI with tractography - 3D reconstruction to assess neural tracts

Question 26

Multiple sclerosis

Answer 26

Autoimmune | Loss of myelin from neurons of CNS

Question 27

MS symptoms

Answer 27

``` Blurred vision Fatigue Difficulty walking Paraesthesia Muscle stiffness ```

Question 28

Peripheral nerve stimulation

Answer 28

Activation of motor axon cause muscle contraction (a twitch) recorded by EMG - M wave Same stimulus may cause activation of sensory axons - travel to spinal cord and cause twitch - H reflex Large stimulus cause activation to occur antidromatically - travel to spinal cord in opposite direction and cause motor neurons to activate - F wave

Question 29

Total motor conduction time

Answer 29

Time from brain to muscle PMCT = (M+F-1)/2 - -1 time taken for action potential to turn around CMCT = TMCT-PMCT In MS - TMCT decrease but PMCT normal