8. Higher cortical function Flashcards
what is the cerebral cortex?
layer of folded grey matter on surface of cerebral hemispheres, from which arise higher cortical functions
where do most cortical inputs and outputs come from?
Inputs come from:
- thalamus (e.g. from somatosensory, visual, auditory systems)
- other cortical areas (communicate with each other).
Outputs: from cortical PYRAMIDAL CELLS to widespread areas.
Name 6 functions of the frontal lobes.
- motor (motor structures sit anterior in CNS)
- speech expression - Broca’s area (usually left hemisphere)
- behaviour regulation/judgement (e.g. Phineas Gage)
- cognition - complex mental tasks (e.g. count down from 100 in 7s)
- eye movements - corticonuclear projections
- continence (medial part as homoncular representation of pelvic floor here)
Name 6 functions of the parietal lobes.`
- sensory (post-central gyrus = primary sensory cortex)
- speech comprehension - Wernicke’s area (usually left hemisphere)
- body image (usually right, neglect if damaged)
- awareness of external environment - attention (neglect if damaged)
- calculation and writing
- visual pathways (superior optic radiation) projecting through white matter
Name 5 functions of the temporal lobes.
- hearing (primary auditory cortex)
- olfaction (primary olfactory cortex in medial part of temporal lobe)
- memory (hippocampus)
- emotion
- visual pathways (inferior optic radiations) projecting through white matter
what is meant by the term cerebral ‘dominance’? Name some examples.
Certain cortical functions are over-represented in 1 hemisphere, with left hemisphere being dominant in 95% of people.
Left hemisphere (sequential processing):
- language
- mathematics/logic
Right hemisphere (‘while picture’ processing):
- body image
- visuospatial awareness
- emotion
- music
What is the corpus callosum? What condition arises if this is absent/damaged?
Large bundle of white matter connecting the 2 hemispheres, allowing them to communicate.
Split brain: subtle deficits
Name the 2 areasimportant in language pathways. Where are these located and how are they connected?
Primarily in dominant (left) hemisphere.
- BROCA’S AREA (BA)
- inferior lateral frontal lobe
- speech production (makes plan for muscular contraction sequence) - WERNICKE’S AREA (WA)
- superior temporal lobe
- language interpretation
Connected via ARCUATE FASCICULUS.
Describe the pathway required for repeating a heard word.
i. Auditory cortex (temporal lobe) sends impulses (related to cochlear impulses) to WA…
ii. WA sends impulses to BA via arcuate fasiculus…
iii. BA sends impulses to primary motor cortex…
iv. PMC sends impulses to muscles of speech to stimulate their contraction.
Describe the pathway required for repeating a written word.
i. Visual cortex (occipital lobe) sends impulses to WA…
ii. WA sends impulses to BA via arcuate fasiculus…
iii. BA sends impulses to primary motor cortex…
iv. PMC sends impulses to muscles of speech to stimulate their contraction.
Describe the pathway required for repeating a ‘thought’.
i. Impulses throughout cortex are sent to WA…
ii. WA sends impulses to BA via arcuate fasiculus…
iii. BA sends impulses to PMC…
iv. PMC sends impulses to muscles of speech to stimulate their contraction.
Name the 2 main types of memory and describe where these are stored.
Memories stored in relatively ‘distributed’ fashion throughout large areas of the brain.
- DECLARATIVE memory (explicit, facts)
- cerebral cortex +/- basal ganglia - NON-DECLARATIVE memory (implicit, motor skills and emotions)
- cerebellum
How are memories stored and how can this change?
i. Short term memory (secs-mins), inc. working memory
ii. Consolidation, depending on:
- emotional context
- rehearsal
- association
iii. Long term memory (up to lifetime)
Which part of the brain is crucial for declarative memory consolidation?
HIPPOCAMPUS
- medial temporal lobe (x2), part of limbic system
- synthesises info from visual, auditory, somatosensory, limbic, ect. systems and transmits to cerebral cortex
How does the hippocampus consolidate declarative memories?
Neuroplasticity - strengthens synapses by:
- increasing transmitter release
- more post-synaptic Rs
- increasing no. of pre-synaptic branches
