Lecture 3 Flashcards
Aphasia
Language disorder caused by a damage on specific area.
Brocas Aphesia
- Difficulty with language production, and grammatical structure.
-Difficulty with writing or reading.
-Understanding speech, motor movements and being able to sing familiar songs remain intact.
Wernicke’s Aphasia
-Word salad
-Comprehension of language is damaged
-Hard to understand the Wernicke’s patients
Anterior Cerebral Circulation
Provides blood flow to anterior parts of the Brain and eyes.
Posterior Cerebral circulation
Provides blood flow to the occipital brain, brain stem and posterior brain.
Example: circle of Willis
Function of Circle of willis ?
-Main oxygenated blood supplier to the brain.
- Joins several main arteries
- If one artery is blocked allow to reroute and continue function
Ischemic stroke
Stroke caused due to blood clotting.
Hemorrhagic stroke
Stoke due to leakage of blood.
What are the stroke statistics?
-Stroke is the third leading cause of death.
-Leading cause of long-terms disability.
-Ischemic stroke is 87%
-25% of the people who recover from their 1st stroke is likely to get their 2nd stroke within 5 years.
Controllable risk factors of stroke?
1- smoking
2- being inactive
3-high blood pressure
4- diet
Uncontrollable risk factor
1- more likely to get it when older
2- men are more likely to get it
3- High chance of inheritance
Symptomps of stroke?
-Dizziness, nausea or vomitting
-severe headache
-confusion, disorientation
-memory loss
-loss of vision etc.
Results of stroke on the right side?
- Paralysis in the left side of the body.
- Vision problems
- quick purposeless behavior
- memory loss
Results of stroke on the left side?
-Paralysis on the right side of the body
-speech language problems
-slow behavior
-memory loss
Neuronal asymmetry
Neural branches and connections differ across the brain
Genetic asymmetry
Gene expressions occur differently in each hemisphere.
Visual asymmetry
If information is presented to the right side of the visual field it is more likely to be processed better on the left hemisphere.
Auditory asymmetry
- When a stimuli “ba” presented to the left hemisphere both ipsilateral and contralateral pathways can reach the info and vice versa.
- ıf different information are presented to both ears “ba” on the left “ga” on the right. Ba will reach the right hemisphere and “ga” will reach the left hemisphere. In order for both information to be present in both sides corpus callosum is necessary.
- has less crossed than other systems
Right ear advantage
When different stimuli are presented simultaneously to both ears, right ear has preferred acces to speaking hemisphere (left)
Example Right ear advantages
1- digits
2-speech
3- nonsense words
(because it connects to left hemisphere)
Example Left ear advantage
1- melodies
2-musical cords
3-environmental sounds
(because it connects to right hemisphere)
Somatosensory asymmetry
- The left hemisphere of a right-handed person is superior at these tasks.
- For right-handed people: right-hand advantage for identifying the letters and left-hand advantage for identifying shapes.
Lateralization
- The brain’s two hemispheres have separate functions.
- Around age 7 the brain is lateralised.
What is lateralized?
1-Visual system
2- Auditory system
3- Somatosensory system
4- Movement
5- Memory
6- Language
7- Spatial process
Double dissociation
when lesions in the same brain region demonstrate a different function for each hemisphere. Example: your right hemisphere can’t compensate for the language lesion on your left hemisphere.
Apraxia
Left hemisphere lesions make it difficult to make or copy voluntary movements. (not due to the muscles due to brain communication)
Split brain
When the two brain hemispheres cannot communicate because the corpus callosum has been damaged or severed; as a result sensory information is only available to one side.
Projection map
-Hierarchy of functions. ( Subcortical structures (Limbic system) can compensate for complex behaviors)
Brodman’s Area (Cytoarchitecture)
-Not concerned with hierarchy
-defined by neural size, shape, packing and the function of the region.
