Lecture 1 Definitions: Perception Intro and Neuroimaging

sensation

the immediate, basic experience generated by external stimuli

perception

the interpretation of sensations, giving them meaning and organization

bottom-up processes

previous experience shouldn’t matter or affect how you process stimuli

top-down processes

processing of info is influenced by expectations which can influence and cause different perceptual experience

thresholds

finding the limits of what can be perceived

signal detection theory

measuring difficult decisions

sensory neuroscience

the biology of sensation and perception

action potential

signal that travels down the length of the axon

refractory period

harder to have an action potential during this time

neuroimaging

set of methods that generates images of the structure and/or function of the brain

computerized tomography (CT)

produces slices of images of the brain based on x-rays passing through the body

magnetic resonance imaging (MRI)

strong magnet makes magnetic field and changes the spin of protons until they lose energy and go back to original place; measuring the rate of return

indirect measure

measuring the consequences of activity

direct measure

picking up electrical potentials or activity

blood oxygen level-dependent (BOLD) signal

the ratio of oxygenated to deoxygenated hemoglobin that permits the localization of brain neurons that are most involved in a task; used in fMRI

positron emission tomography (PET)

measures the decay of radioisotopes in the body

electroencephalography (EEG)

measures brain electrical activity at the scalp from the rapid post-synaptic potential changes of pyramidal cells in the cortex

pyramidal cells

highly concentrated at upper portion of cortical surface

event-related potentials (ERP)

created by averaging together many EEG trials time-locked to a specific event

magnetoencephalography

a technique similar to EEG that measures changes in magnetic activity across populations of many neurons in the brain