Cortical organisation and function Flashcards
How is the brain organized on a microscopic level?
Organised into 6 layers and columns
what is the name given to the structure that seperates the frontal and parietal lobes of the brain?
central sulcus
what is the name and primary function of the structure located directly anteriorly to the central sulcus?
pre-central gyrus, primary motor cortex.
what is the name and primary function of the structure located directly posteriorly to the central sulcus?
post-central sulcus, primary somatosensory cortex
what are the 5 main functions of the frontal lobe?
regulation and initiation of motor function. language. cognitive functions. attention. memory
what are the 4 main functions of the parietal lobe?
sensation, senory aspects of language, spatial orientation and self-perception
what is the main function of the occipital lobe?
processing visual information
what are the three main functions of the temporal lobe?
processing auditory information, emotions and memories
What parts of the brain is the limbic lobe composed of?
amyglada, hippocampus, mamillary body and cingulate gyrus
what is the function of the limbic lobe?
is concerned with learning, memory, emotion, motivation and reward
where is the insular cortex located?
deep within the lateral fissure
what is the function of the insular cortex?
concerned with visceral sensations, autonomic control, interoception, auditory processing, visual-vestibular integration (sense of reality)
What is grey matter composed of?
neuronal cell bodies and glial cells.
what is white matter composed of?
myelinated neuronal axons
How are cortical areas connected?
by white matter tracts
what are association fibres?
connect areas within the same hemisphere
what are commisural fibres?
connect homologous structures in left and right hemispheres
what are projection fibres?
connect cortex with lower brain structures (thalamus, brain stem and spinal cord)
which specific fibre tract connects frontal and occipital lobes?
superior longitudinal fasciculus
which specific fibre tract connects frontal and temporal lobes?
arcuate fasciculus and uncinate fasciculus
which specific fibre tract connects temporal and occipital lobes?
inferior longitudinal tract
what are the two main commissural fibres?
corpus callosum and anterior commissure
in what direction do afferent projection fibres go?
towards cortex
in what direction do efferent projection fibres travel?
away from cortex
describe what happens to projection fibres as they move deeper to the cortex
radiate as the corona radiata and converge through internal capsule between thalamus and basal ganglia
what is the difference between primary cortices and secondary/association cortices?
primary cortices have a predictable function, secondary less so. Primary are organised topographically, secondary are not. primary cortices show symmetry between left and right hemispheres, secondary have a weak or absent symmetry
what is the function of the primary motor cortex?
control of fine, discrete, precise voluntary movements. Provides descending signals to execute movements.
what is the function of the supplementary motor area?
involved in planning complex movements (internally cued)
what is the function of the premotor area?
involved in planning movements (externally cued)
what is the function of the primary somatosensory cortex?
processes somatic sensations arising from receptors in the body (fine touch, vibration, propioception, pain and temperature)
what is the function of the somatosensory association area?
interpret significance of sensory information e.g. recognizing an object placed in hand. awareness of self and personal space
what is the function of the primary visual area?
process visual stimuli
what is the function of the visual associated area?
gives meaning and interpretation of visual input
what is the function of the primary auditory lobe?
processes auditory stimuli
what is the function of the auditory association area?
gives meaning and interpretation of auditory input?
what is the function of Brocas area (association)?
production of language
what is the function of the prefrontal cortex (association area)?
attention, adjusting behaviour, planning, personality expression, decision making
what is the function of Wernickes area?
understanding of language
What do frontal lobe lesions cause?
changes in personality and inapropiate behaviour
what do parietal lobe lesions cause?
contralateral neglect, lack of awareness of self and awareness of extrapersonal space
what do temporal lobe lesions cause?
agnosia- inability to recognise
what occurs following a lesion to Brocas area?
Expressive aphasia - poor production of speech but communication intact
what occurs following a lesion to Wernickes area?
Receptive aphasia - poor comprehension of speech, production is fine
What occurs following a lesion to the primary visual cortex?
blindness in the corresponding part of visual field
what occurs following a lesion to the visual association area?
deficits in interpretation of visual information e.g. prosopagnosia, the inability to recognize familiar faces or learn new faces
What are the three ways in which cortical function can be assessed?
imaging, encephalography, brain stimulation
What happens in a positron emission tomography (PET) scan?
radioactively labelled glucose injected into blood. person asked to undertake a task, blood flows directly into that brain region
What is tested for during a functional magnetic resonance imaging (fMRI) test?
amount of blood oxygen a region of the brain is receiving
What is an ECG used to measure?
electrical signals produced by the brain
what is an MEG used to measure?
magnetic signals produced by the brain
What is transcranial magnetic stimulation (TMS) used to assess?
functional integrity of the neural circuits using electromagnetic induction to stimulate neurons
