L9 - Higher cortical functions Flashcards
Inputs to the cerebral cortex
Mainly from the thalamus
Also from the cortex itself
Pyramidal cells
Many dendrites as many synapses Outputs to the cortex itself, tracts to: - brainstem - spinal cord - cerebellum - basal ganglia
Frontal lobe functions
Motor function - primary motor cortex
Speech production - Broca’s area
Behavioural regulation or judgement
Cognition
Eye movements - contains the occulomotor nuclei
Continence - contains UMNs that supply external anal/urinary sphincters
Parietal lobe functions
Sensory - primary sensory cortex
Understanding speech - wernicke’s area in left hemisphere
Body image - left hemisphere controls right side
Awareness of external environment (attention)
Calculation and writing
Superior optic radiations project through the white matter
Hemisensory neglect
Not aware of other side of body
E.g lesion in right parietal lobe - not aware of left side of body therefore shave only on right side of face
Temporal lobe functions
Hearing - primary auditory cortex Olfaction - primary olfactory cortex Memory - hippocampus Emotion Inferior optic radiations project through the white matter
Concept cells and boundary cells
Concept cells
- unique to humans
- stimulated by concepts
- concept neurone for each person known
Boundary cells
- geographical awareness
- stimulates e.g. by getting to close to a wall
Left hemisphere dominance
Sequential processing e.g.
- language
- mathematics and logic
Dominant in 95% of people
Right hemisphere dominance
Whole picture processing
- body image
- visuospatial awareness
- emotion
- music
Left hemisphere damage
The right hemisphere attends to both halves of space but the left hemisphere only attends to the right half of space therefore the right hand side awareness can still be intact as the right hemisphere compensates
Corpus callosum
Bundle of white matter connecting the two hemispheres
Supplied by the anterior cerebral artery
Lesion can cause alien hand syndrome
Where are language pathways?
Primarily in the dominant left hemisphere (95% people)
Where is the Broca’s area situated?
Inferior lateral frontal lobe in the left hemisphere
In close proximity to the pre central gyrus (primary motor cortex) as can send impulses to instruct the correct muscle contractions for speech
What does the Broca’s area do?
Controls speech production
Wernicke’s area location
Left hemisphere
Superior temporal lobe in the junction between the parietal and temporal lobe
Close proximity to the primary auditory cortex
Function of Wernicke’s area
Speech comprehension
Arcuate fasciculus
Region of white matter tracts that connect the Wernicke’s area to the Broca’s area
Pathway for repeating a heard word
- The primary auditory cortex in the superior temporal lobe sends imputes to the Wernicke’s area
- The Wernicke’s area translates vibrations from the cochlear into language
- The Wernicke’s area sends impulses via the arcuate fasciculus to the Broca’s area
- The Broca’s area communicates with the primary motor cortex to instruct the right sequence of muscle contractions for speech
Pathway for speaking a written word
- The primary visual cortex sends impulses to the Wernicke’s area
- The Wernicke’s area translates the pattern of words into language
- The Wernicke’s area sends impulses to the Broca’s area via the arcuate fasciculus
- The Broca’s area sends impulses to the primary motor cortex to control the sequence of muscle contractions for speech
Pathway for speaking a thought
- Inputs from all over the cortex are sent to the Wernicke’s area
- The Wernicke’s area translates thoughts into language and sends the impulses to the Broca’s area via the arcuate fasciculus
- The Broca’s area sends impulses to the primary motor cortex for speech
Wernicke’s aphasia
Wernicke’s area damaged - speech does not make sense
Broca’s area intact - can produce speech correctly
- are not distressed
Broca’s area
Broca’s area damaged - can not produce speech properly
Wernicke’s area intact- does make sense
- distressed as understand that speech is not correct
Classification of memory
Declarative: explicit:
- facts
Nondeclarative: implicit
- motor skills - behaviours
- emotions
Where are memories stored
Memories are distributed throughout the brain
Explicit - cerebral hemispheres
Implicit - cerebellum and basal ganglia
Learning new skills
Majority of the memories are in the cerebral cortex as are using the primary motor cortex and primary sensory cortex
As the skill is learnt, the memories are transferred to the cerebellum for automaticity so recall is more rapid
How are memories stored
- First in short term memory
- Consolidated and rehearsed into long term memory
- Depends on emotion, rehearsal and association
Hippocampus
Consolidates declarative memories
Receives inputs from all over the brain e.g visual and auditory system and converges them to make associations
Where is the hippocampus
Deep in the temporal lobe
Neuroplasticity and memory
Long term potentiation can strengthen synaptic connections therefore making memories
