This information is used to determine which area is most active.-Weakness of this technique: There is only so much radioactivity a person canbe exposed to.-This technique is not particularly common.3.Functional and Structural Magnetic Resonance Imagery-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 deoxygenatedblood-Fluctuating levels of oxygen in the blood is indicative of which parts of thebrain is activated.-Pros: 1)Non-Invasive2)Good spatial recognition3)Well validated in the scientific community4)About 1,000 papers published per month involving studies done withfMRIs and sMRIs-Cons1)Poor temporal recognition2)Many ways to analyze the resulting image3)No “gold standard”4)Hard to validate4.MagnetoEncephaloGraph-MEG-Measures magnetic fields produced by electrical activity in the brain-Magnetic activity decays with the space- MEG is only good for detectingactivity within the cerebral cortex-Excellent temporal resolution and better spatial resolution than EEG5.Brain Stimulation-Transcranial Magnetic Stimulation- TMS-Induces temporary lesions or activates certain areas of the brain-Problems with TMS:1)Hard to localize what we are affecting2)Hard to know the degree of stimulation3)The stimulation we can cause is limited to the cerebral cortex (onlyabout 2cm deep, can’t stimulate deep structures like thehypothalamus)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
Lecture #4- PerceptionSensations are detected by sensory receptors/organs and perceptions are the interpretationour brain makes of these sensations.SensationPerceptionExamples of Sensations vs Perceptions:SensationsPerceptionsTasteLoudnessProprioceptionPitchTouchBrightness of coloursSmallBeautySight PainHearingPleasant/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 agenetic 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 ofcolor.VISION- Our Dominant Sense-The McGurk Effect:-A multisensory illusion in which a change in auditory perception is the result of a shift invisual input.-Classically demonstrated by the use of the sound “ba” that is shown with the mutedvideo of either a person saying “fa” or the correct sound.Stimulus/EnergyLight, sound, smell, etc.Sensory ReceptorsEyes, ears, nose, etc.Neural ImpulseBrainVisual, auditory, olfactory areas.
-It is only with closed eyes that a person can correctly identify the sound from theincongruent video. Otherwise, they will always hear the sound “fa”.