Cortical Organisation and Function Flashcards by Ell Loukily

What is the cerebral cortex?

Covers entire surface of the brain
Together with deep nuclei, contains grey matter
Highly folded with gyri and sulci
Organised into lobes

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What are the layers of the cerebral cortex?

Molecular layer (I)
External granular layer (II)
External parietal layer (III)
Internal granular layer (IV)
Internal pyramidal layer (V)
Multiform layer (VI)

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How is the brain classified?

It classified based on cytoarchitecture (cell size, spacing or packing density and layers)

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What is the role of the frontal lobe?

Regulating and initiating motor function
Language
Cognitive function (executive function [e.g. planning])
Attention
Memory

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What is the role of the parietal lobe?

Sensation - touch, pain
sensory aspects of language
spatial orientation and self-perception

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What is the role of the occipital lobe?

processing visual information

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What is the role of the temporal lobe?

Processing auditory information
Emotions
Memories

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What is in the limbic lobe?

Includes the amygdala, hippocampus, mamillary body, and cingulate gyrus

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What is the role of the limbic lobe?

Concerned with learning, memory, emotion, motivation and reward

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Where is the insular cortex found?

Deep within the lateral fissure

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What is the role of the insular cortex?

Concerned with visceral sensations, autonomic control, and interoception, auditory processing, visual-vestibular integration (related to motion suckness)

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What is grey matter?

neuronal cell bodies and glial cells – around 85 billion of each

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What is white matter?

Myelinated neuronal axons arranged in tracts

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What is the role of white matter tracts and what are the 3 different fibres?

Connect cortical areas:

Association fibers
Commissural fibres
Projection fibres

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What is the role of association fibres?

connect areas within the same hemisphere

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What is the role of commissural fibres?

Connect homologous structure in left and right hemispheres

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What is the role of projection fibres?

connect cortex with lower brain structures (e.g. thalamus, brain stem and spinal cord)

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What are the different types of association fibers?

Short fibres

Long fibres

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

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What are the different types of commissural fibres?

Corpus callosum

Anterior commissure

What are the different types of projection fibres?

Afferent- towards cortex
Efferent- away from cortex
Deeper to cortex radiate as corona radiata
Converge through internal capsule between thalamus and basal ganglia

What are features of primary corticies?

Function predictable 
Organised topographically  (parts of body controlled by particular parts of brain like homunculus)
Symmetry between left and right

What are features of secondary/association cortices?

Function less predictable
Not organized topographically
Left-right symmetry weak or absent

What is the role of the primary motor area?

controls fine, discrete, precise voluntary movements.

Provides descending signals to execute movements.

What is the role of the supplementary motor area?

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

What is the role of the premotor area?

involved in planning movements (e.g. externally cued)

What is the role of the primary somatosensory area?

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

What is somatosensory association?

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

What is the role of the primary visual area?

Process visual stimuli

What is the role of the visual association?

Gives meaning and interpretation of visual input

What is the role of the primary auditory area?

Process auditory stimuli

What is the role of the auditory association?

Gives meaning and interpretation of auditory input

What is the role of Broca's area?

Production of language

What is the role of Wernicke's area?

Understanding of language

What is the role of the prefrontal cortex?

``` Attention Adjusting social behavior Planning Personality expression Decision making ```

What is the consequence of frontal lobe lesions?

Changes in personality | Inappropriate behavior

What is the consequence of parietal lobe lesions?

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

What are consequences of temporal lobe lesions?

Agnosia and inability to recognise

What are consequences of a lesion to Broca's area?

Expressive aphasia – poor production of speech, comprehension intact

What are consequences of a lesion to Wernicke's area?

Receptive aphasia – poor comprehension of speech, production is fine

What are consequences of a lesion to the primary visual cortex?

blindness in the corresponding part of the visual field

What are consequences of a lesion to the visual association?

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

What are different imaging techniques we can sue to assess cortical function?

Positron emission tomography (PET)- looks at blood flow directly to brain region (tells you what brain is using during task) Functional magnetic resonance imaging- looks at amount of blood oxygen in brain region

How is encephalography carried out?

Use of: Visual evoked potentials Event-related potentials/ evoked potentials A large stimulus is needed to see any traces. An average of these traces are then taken to show waves These signal differences can show you where there may be a problem on the path By using somatosensory evoked potentials we can look at: somatosensory activity, thalamic activity, mid cervical cord activity and impulses arriving at shoulder A series of waves that reflect sequential activation of neural structures along the somatosensory pathways is produced

What encephalography techniques can be used to assess cortical function?

Electroencephalography (EEG)- measures electrical signals produced by the brain (looks at things such. as seizure activity or sleep disturbances) Magnetoencephalography (MEG)- measures magnetic signals produced by the brain (immobile and expensive)

What brain stimulation techniques can be used to assess cortical function?

Transcranial magnetic stimulation (TMS)- Asses functional integrity of neural circuits. Uses EM induction to stimulate neurons Transcranial direct current stimulation (tDCS): Uses low direct current over the scalp to increase or decrease neuronal firing rates

What imaging techniques can be used to asses structure??

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