Cortical Association Areas Flashcards
Tell me about where the cortex inputs and outputs from.
The cortex has VI layers before white matter
Inputs to layer IV from:
- Motor and sensory cortices
- Thalamus
- Brainstem
Outputs: From layer V and VI to: - Hippocampus - Basal ganglia - Cerebellum - Thalamus From layers I, II and III to: - Other cortical association areas
What are association areas of the lobes?
Frontal lobe:
- Higher intellect
- Personality
- Mood
- Social conduct
- Language
Parietal lobe:
- Dominant hemisphere - language calculation
- Non-dominant hemisphere - visuospatial functions
Temporal lobe:
- Memory
- Language
Occipital lobe:
- Vision
They all work together for single thought or understanding
What problems occur in a frontal lobe lesion?
Diverse
Personality and behavioural changes
Inability to solve problems
What problems occur in a parietal lobe lesion?
Attention deficits
e.g. right hemisphere damage > contralateral neglect syndrome
What problems occur in temporal lobe lesions?
Recognition deficits:
agnosias
e.g. prosopagnosia > failure to recognise faces
What problems occur in global lesions?
Dementia> cognitive deficits
e.g. Alzheimer’s, cerebrovascular disease
What is meant by lateralization in the brain?
Different hemispheres are more specialised in different functions
Dominant hemisphere (95% left hemisphere)
Language: - Spoken/heard - Written/read - Gestured/Seen Maths Logic Motor skills (handedness)
Non-Dominant hemisphere Emotion of language Music/Art Visuospatial Body awareness
What connects the two hemispheres? And what problems occur with lesions to this?
Corpus callosum (anterior commissure)
Lesion of corpus callosum:
Two separate conscious portions - dominant side could elicit response from written word without non-dominant knowing why
What areas are involved of the lateralisation of language?
Two important areas:
Wernicke’s area
- Interpretation of written and spoken words
Broca’s area
- Formulation of language components, sends info to motor cortex
What is the pathway for speaking a heard word?
and speaking a written word
Primary auditory area then Wernicke's area (via Arcuate fasciculus, to) Broca's area Then Motor cortex
For a written word, it starts off in primary visual cortex, then via angular gyrus to Wernicke’s area and so on.
What is Wernicke’s aphasia?
Receptive, sensory or central aphasia
Dominant side:
- Disorder of comprehension
- Fluent but intelligible speech - jargon aphasia
- Loss of mathematical skills
What is Broca’s aphasia?
Expressive or motor aphasia
Poorly constructed sentences, dis-jointed speech
Comprehension is fine.
Name some other aphasias.
Conduction
Nominal/amnesic
Global or total
How are memories stored?
Memories are stored throughout the cortex
Declarative or procedural
Synaptic changes
Are a consequence of neuronal plasticity
Declarative:
hippocampus and various cortical regions
Procedural:
Cerebellum, pre-motor cortex, basal ganglia
How are memories formed?
Senses > cortical sensory areas > amygdala and hippocampus > diencephalon, basal forebrain, pre-frontal cortex > cortical sensory areas
What does destruction of hippocampus cause?
Anterograde amnesia
Failure to form new memories
What is amnesia?
Different forms of memory loss or ability to make memories.
Vascular interruption, tumours, trauma, infections vitamin B deficiency (Korsakoff’s syndrome), ECT
Retrograde amnesia:
Failure to retrieve old memories (Alzheimer’s)
Transient global amnesia (TIA)
