Weakness of this technique There is only so much radioactivity a person can be

Weakness of this technique there is only so much

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This information is used to determine which area is most active. - Weakness of this technique: There is only so much radioactivity a person can be exposed to. - This technique is not particularly common. 3. F unctional and S tructural M agnetic R esonance I magery- fMRI and Smri - The fMRI focuses on activity in the brain and the sMRI looks at anatomy - Involves a very large magnet that detects oxygenated and deoxygenated blood - Fluctuating levels of oxygen in the blood is indicative of which parts of the brain is activated. - Pros: 1) Non-Invasive 2) Good spatial recognition 3) Well validated in the scientific community 4) About 1,000 papers published per month involving studies done with fMRIs and sMRIs - Cons 1) Poor temporal recognition 2) Many ways to analyze the resulting image 3) No “gold standard” 4) Hard to validate 4. M agneto E ncephalo G raph- MEG - Measures magnetic fields produced by electrical activity in the brain - Magnetic activity decays with the space- MEG is only good for detecting activity within the cerebral cortex - Excellent temporal resolution and better spatial resolution than EEG 5. Brain Stimulation - T ranscranial M agnetic S timulation- TMS - Induces temporary lesions or activates certain areas of the brain - Problems with TMS: 1) Hard to localize what we are affecting 2) Hard to know the degree of stimulation 3) The stimulation we can cause is limited to the cerebral cortex (only about 2cm deep, can’t stimulate deep structures like the hypothalamus) How Do We Decide Which Tool to Use? 1. Think about what you want to know first (temporal, spatial?) 2. Always best to use multiple techniques (validity and reliability) 3. Cost is also a factor
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Lecture #4- Perception Sensations are detected by sensory receptors/organs and perceptions are the interpretation our brain makes of these sensations. Sensation Perception Examples of Sensations vs Perceptions: Sensations Perceptions Taste Loudness Proprioception Pitch Touch Brightness of colours Small Beauty Sight Pain Hearing Pleasant/Unpleasant *Confused Sensation- Synesthesia -When the stimulation of one sense simultaneously produces another sensation in a different modality. -The cause is unknown but believed to be a result of neural wiring. Might also be a genetic condition. -Can arguably be a taught condition according to Colizoli et al. 2016. Colizoli’s study, However, did not have a control group. Example : Grapheme-color synesthesia - seeing numbers and letters in different colors. Sound and color synesthesia - When music’s associated to rich visual experiences of color. VISION- Our Dominant Sense -The McGurk Effect : -A multisensory illusion in which a change in auditory perception is the result of a shift in visual input. -Classically demonstrated by the use of the sound “ba” that is shown with the muted video of either a person saying “fa” or the correct sound. Stimulus/Energy Light, sound, smell, etc. Sensory Receptors Eyes, ears, nose, etc. Neural Impulse Brain Visual, auditory, olfactory areas.
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-It is only with closed eyes that a person can correctly identify the sound from the incongruent video. Otherwise, they will always hear the sound “fa”.
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