Higher Cortical Function Flashcards
Outline the structure of the cerebral cortex
arranged as 6 laters containing cell bodies + dendrites (grey matter)
What are most of the outputs of the cortex from?
Axons of pyramidal neurones
Three types of output fibres
- Projection fibres: from cortex to brainstem
- Commissural fibres: between hemispheres
- Association fibres: connecting nearby regions of cortex in same hemisphere
Where are most of the inputs to the cortex from
Thalamus
Other cortical areas
Function of frontal lobe
- voluntary motor control
- expression of speech (left)
- behavioural regulation
- cognition
- eye movements
- continence
Function of parietal lobe
- somatosensory perception
- comprehension of speech (left)
- body image (right)
- spatial awareness
- calculation + writing
Function of temporal lobe
- hearing
- smell
- taste
- memory
- emotion
- long term memory
- comprehension of speech (left)
- emotion at limbic system
What hemisphere is dominant in most people?
Left
What is the left hemisphere dominant for?
Language
Mathematical/logical function
What is the right hemisphere dominant for?
Body image
Visuospatial awareness
Emotion
Musical ability
Where are the language pathways dominants?
Left hemisphere
What is involved in language pathways + their function?
- Broca’s area: production of speech
- Wernicke’s area: interpretation of language
- arcuate fasciculus: connects the two
Pathway for repeating a heard word
left hemisphere
- auditory cortex in temporal lobe
- signal sent to wernicke’s area
- signal to Broca’s area via arcuate fascicilus
- signal sent to primary motor cortex to elicit speech
Pathway for speaking a written word
- left hemisphere
- visual cortex in occipital lobe
- signal sent to wernicke’s area
- signal to Broca’s area via arcuate fascicilus
- signal sent to primary motor cortex to elicit speech
Location of Broca’s area
Inferior lateral frontal lobe
Location of Wernicke’s area
Superior temporal lobe
What can damage to Broca’s area cause?
Expressive aphasia
Staccato speech
Patient will still understand what is being said to them but can’t speak properly
What can damage to Wenicke’s area cause?
Receptive aphasia
Fluent, nonsensical speech
But patient doesn’t appear to understand what is being said to them
What does damage to the arcuate fasciculus cause?
Inability to repeat heard words
What are the types of memory?
What do they store and where?
- declarative/explicit: factual information in cerebral cortex
- non-declarative/implicit: motor skills + emotion in subcortical structures e.g. basal ganglia + cerebellum
- short term memory: in cortical circuits
- long term memory: in cerebral cortex, cerebellum
What does declarative/explicit memory store + where?
Factual information
In cerebral cortex
What does non-declarative/implicit memory store + where?
- Motor skills + emotion
- stored in subcortical structures e.g basal ganglia + cerebellum
Where is short vs long term memory stored?
- short: in cortical circuits
- long: in cerebral cortex, cerebellum
What is consolidation?
Process of converting short term memories into long term memories
What factors influence consolidation?
- emotional context
- rehearsal
- association
Location of hippocampus
Deep in temporal lobe
Function of hippocampus
Facilitates consolidation of memories in cortex via its output pathways
Outline the main output pathway of the hippocampus
Fornix > mammillary bodies > thalamus > cortex
What is the key molecular mechanism of memory consolidation?
Long term potentiation
Role of long term potentiation in memory consolidation
- Causes changes in glutamate receptors in synapses
- Leads to synaptic strengthening
What is alien hand syndrome?
When one hand has a ‘mind of its own own’ and is not controlled properly by the brain
What causes alien hand syndrome?
Damage in corpus callosum
What is aphasia?
Acquired disorder of language resulting from brain damage to dominant hemisphere
What is dysarthria?
Form of motor speech disorder which involves the abnormal articulation of sounds affecting speed, strength, timing, range + accuracy of movements
What can damage to corpus callosum cause?
Alien hand syndrome
Effects on language processing
What can cause global aphasia?
Middle cerebral artery stroke
What do the inferior and superior division of MCA supply?
superior - Broca’s area
inferior - Wernicke’s area
