Kinesiology 1080A/B Lecture Notes - Lecture 7: Developmental Coordination Disorder, Parietal Lobe, Transcranial Magnetic Stimulation
16 Oct 2018
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Spatial Numerical Association of Response Codes: (SNARC effect)
- Most people represent a mental number line from left to right in an ascending order
o Standard representation, more analytical person
- More creative people have a different mental number line than standard
- Experiment:
o Flash 1 and 2 in left visual field, have shorter reaction times than if flashing 8 or 9
o Flash 8 or 9 in right visual field, shorter reaction time than 1 and 2 in same visual field
o Faster reactions when stimulus is spatially compatible with our internal mental number line
o Can increase complexity by pointing to numbers instead of flashing, therefore can have
shorter movement times when compatible with mental number line
- First languages that are not written from left to right have a different internal mental representation
- Occurs in frontoparietal network:
o Involves parietal and frontal structures
o Thought to be lateralized to the right hemisphere
o Close eyes and envision number line in right pre-frontal cortex (PFC)
- Transcranial magnetic stimulation (TMS)
o Allows to send a magnetic impulse to cortex of participant (virtual lesion)
o With TMS you can mimic a stroke in a healthy brain→only a couple msec
o Fairly safe procedure
o Asked to think about mental number line and perform same experiment in a specific visual
o When applied TMS to right PFC, slows reaction time and no longer show SNARC
effect, does not have much of an impact on left
Microscopic Cerebral Asymmetry:
- Left and right hemispheres look exactly the same
- However: for Broca’s region, take tissue samples and examine under microscope, there are different
neurons in each area (left Broca and right Broca’s area)
- neurons in the left, speech region of our brain are more complex than the homologous (opposite)
right brain
o density of magnopyramidal cells→biggest, most complex neurons in brain, most dendritic
trees
o still unknown why they are better
Praxis:
- ability to string together complicated movements →lateralized in left cerebral hemisphere because
those who have lesions in left cerebral hemisphere have apraxia
- Apraxia: disorder of learned, skilled purposeful movement, not related muscle paralysis
comprehension deficits
o High level movement disorder→exclude low level functions like aphasia or ataxia prior to
diagnosing
o If all that is left over is a movement disorder, it is defined as apraxia
Types of Apraxia:
1. Ideational Apraxia: inability to evoke appropriate action representation from long-term memory
o Ask how to do something and simply say “I don’t know”
o Loss of ability to perform movements for daily living
2. Ideomotor Apraxia:
o disconnection between knowledge of how to do something and movement centres
o Tell them what they should do, but when asked to perform movement they can’t
o Know what they want to do but can’t do it
- If demonstrating apraxic movements 6 months after acute recovery (rehab), will most likely stay in
this condition
Document Summary
Spatial numerical association of response codes: (snarc effect) Most people represent a mental number line from left to right in an ascending order: standard representation, more analytical person. More creative people have a different mental number line than standard. First languages that are not written from left to right have a different internal mental representation. Involves parietal and frontal structures: thought to be lateralized to the right hemisphere, close eyes and envision number line in right pre-frontal cortex (pfc) Left and right hemispheres look exactly the same. Apraxia: disorder of learned, skilled purposeful movement, not related muscle paralysis comprehension deficits: high level movement disorder exclude low level functions like aphasia or ataxia prior to diagnosing. If all that is left over is a movement disorder, it is defined as apraxia. If demonstrating apraxic movements 6 months after acute recovery (rehab), will most likely stay in this condition. Occur in greater frequency during left cerebral lesion.
