Higher Cortical Function Flashcards
Describe the major inputs to and outputs from the cerebral cortex.
Inputs = mostly from the thalamus and from other cortical regions e.g. the reticular formation.
Outputs = Axons of pyramidal neurons (eg UMNs) that have widespread projections.
a. Projection fibres (to brainstem / spinal cord)
b. Commisural fibres (between hemispheres)
c. Association fibres (between regions of the same hemisphere)
Name the major functions of the frontal lobe and which areas denote this function.
Motor - primary motor cortex
Expression of Speech - Brocas area
Behavioural regulation / judgement - Prefrontal cortex
Cognition - Prefrontal cortex
Eye movements (motor role)- frontal eye fields, problems with conjugate eye gaze
Continence (motor role)- paracentral lobules.
Name the major functions of the parietal lobe and which areas denote this function/
Sensory - primary sensory cortex
Comprehension of speech - Wernickes area
Body image and awareness of external environment - involved in eating disorders, hemispatial neglect
Calculation and writing - works with frontal lobe
What lesion would produce signs and symptoms of hemispatial neglect?
Right sided parietal lesions can result in hemispatial neglect. This is where the patient will neglect the whole left side of the world and have no insight into the condition they have (cannot contemplate that they have it).
Left sided parietal lesions DO NOT result in hemispatial neglect because the right hemisphere is able to compensate.
Name the major functions of the temporal lobe and the areas which denote these functions.
Hearing - primary auditory cortex sits near to Wernickes area
Olfaction - Primary olfactory cortex
Memory - Hippocampus
Emotion - limbic system e.g. hippocampus, amygdala
What pathology can trigger feelings of de ja vu and why?
Temporal lobe epilepsy due to the location of the hippocampi within the temporal lobe (and its subsequent roles in memory consolidation)
What hemisphere is dominant for language production?
Left
What effects can destruction of the corpus callosum lead to?
Deficits such as…
Alien hand syndrome
Language processing
Where is Broca’s area located?
In the Infero-lateral frontal lobe, near to the mouth/pharynx area of the primary motor cortex (due to its roles in the production of speech)
What is the difference between expressive and receptive aphasia?
Expressive aphasia = Brocas area = can understand speech, but have problems in the production of speech = ‘staccato speech’
Receptive aphasia = Wernickes area = have no problem in the production of speech, but this will be nonsensical as the understanding of speech is impaired.
Where is Wernicke’s located?
Located at the parieto-temporal junction, near to the primary auditory cortex in the temporal lobe (due to its role in hearing speech).
What connects Broca’s and Wernicke’s areas? What would a lesion in this pathway lead to?
Arcuate fasciculus
Lesion to the white matter pathway (association fibres) would lead to the patient being unable to repeat heard words.
What is declarative/ explicit memory?
Memory of factual information e.g. the capital of France is Paris.
Tends to be stored in the cerebral cortex.
What type of memory does memory of motor skills and emotion come under, and where do they tend to be stored in the brain?
Non-declarative / implicit memory
Stored in subcortical areas such as the basal ganglia, and also in the cerebellum.
Where are short and long term memories stored?
Short term memory stored for seconds to minutes as a reverberation in cortical circuits.
Long term memory is stored for very long periods in the cerebral cortex, cerebellum after consolidation.
What is consolidation?
The act of converting short term memories to long term memories.
This can be influenced by the emotional context, rehearsal of short term memories, and association.
Which structure is involved in consolidating declarative memories?
The hippocampus acts as an oscillator to facilitate the consolidation of memories in the cortex via its output pathways (fornix–>mammilary bodies –> thalamus –> cortex)
What is LTP and how does the process enable memory consolidation?
Long term potentiation involves the changes in glutamate receptor activity leading to synaptic strengthening / learning. Increased NMDA activity leads to the upregulation of AMPA receptors, which in turn will make it easier to activate NMDA receptors in the future (= storage and retrieval of memory)
LTP also involves the development of new physical connections.
