Module 3 Flashcards
Is dementia a disease?
No, it is a clinical label
What is dementia?
A clinical syndrome characterized by a decline in cognitive function (memory, language, executive function)
What is crystallized function?
When a function stabilizes over time (in the case of vocabulary proficiency, it actually increases)
What is the distinction between cognitive impairment and dementia?
The severity of affected function
What is crucial for implementing effective treatment of Alzheimer’s?
Early detection
What is speech prosody?
the intonation in voice marking emotional speech
Generally, what do we think the left hemisphere is responsible for?
Language and speech
What do we think the right hemisphere is responsible for?
Spacial processing, face perception, music perception, speech prosody
Why is hemispheric specialization more efficient?
it reduces the length of axial connections and reduces redundancy
Where is the right hemisphere larger than the left?
in the anterior brain
Where is the left hemisphere larger than the right?
in the posterior brain
What is the planum temporale responsible for?
speech perception (is larger in the left hemisphere) - language comprehension
What is the corpus callosum?
A fibre bundle connecting the two hemispheres
How do we study lateralized functions in the brain?
- lateral lesions
- commissurotomy
- dichotic listening experiment (audition)
- PET, fMRI, ERP
Describe the connections of the corpus callosum?
- homologous sites in the contalateral hemisphere
- projection sites of a homotopic area (fibres go to projection sites)
- diffuse projections
Do primary cortical areas project contralaterally?
They tend not to
What happens in split-brain procedures?
- The corpus callosum is severed, therefore the hemispheres cannot communicate with each other
- the hemispheres still receive and control contralateral muscles
Where do motor and somatosensory input cross over?
At the brain stem
What happens in normal individuals when they see a stimulus?
The info in the left visual field is projected to the right visual cortex, which sends it to the left for communication
- in split brain individuals, the right hemisphere sees it but cannot communicate what the information is
How are the left and right hemispheres different neuroanatomically?
- planum temporale is larger (up to 10x) in the left than the right
- Broca’s area is larger on the left than the right
How are the left and right hemispheres different at the cellular level?
- columns of cells are more spread out in auditory areas of left than right
- more pyramidal cells in the left than the right
How are the hemispheres different neurochemically?
- there is more noradrenaline in the right thalamus than the left
- there is more dopamine in the left basal ganglia than in the right
Who discovered hemispheric specialization?
Paul Broca
What does the right brain excel at that the left brain does not?
Spatial and non-verbal tasks
Where is language processing for right handed people?
In the left hemisphere
What does damage to the right hemisphere cause?
Impairment in line orientation distinction, facial recognition, tones of sound and pitches of voice, and ability to interpret emotional facial expressions
What is cerebral dominance?
The idea that one hemisphere dominates a mental function
What is a commissure?
Structures that connect the hemispheres
What is the Wada technique?
a technique that anesthetizes one half of the brain
What is a better way to think about how the brain organizes function?
The hemispheres aren’t really divided by WHAT is being processed, but HOW it is processing it
How does the left hemisphere process information?
In an analytical fashion in which information is broken down into smaller components (ex. seeing vegetables or z)
How does the right hemisphere process information?
In a holistic fashion in which information is integrated into a whole (ex. seeing a face or M)
What is perceptual asymmetry?
the asymmetry of the perception of stimulation, depending on what part of the sensory system is stimulated
What is the direct access theory?
The theory that states that the info is processed in the same hemisphere that it was received in
What does the callosal relay model describe?
The theory that states that info is sent to the hemisphere that can process it better
What is the wharfium hypothesis?
The idea that language shapes our perception
How fast is information transmitted from one hemisphere to another?
approximately 15-20 milliseconds
What is special about left handed people?
They hold a lot of exceptions in lateralization
- 70% still hold language processing in the left hemisphere, but some can have bilateral language processing abilities, or even contralateral processing
What are preferred cognitive modes?
left = verbal, analytical right = spatial, synthetic (synthesizes), Gestalt
What is cognitive reserve?
Better cognitive function in the face of brain pathology due to level of education, language fluency, etc.
