Psy 3061 1st EditionExam # 2 Study Guide Lectures: 1 - 7Brain recordingElectrophysiologyIntracellular recording is measuring the changing voltage inside of a neuron. Extracellular recording is measuring the changing voltage outside of one or more neurons. Methods are more often used for central nervous system like intracellular recording. Intracellular cell recordings are used for measuring postsynaptic potentials (PSPs). When the neuron fires an action potential, the voltage value rapidly spikes and returns to baseline.Extracellular recording records the electrical disturbances that are created each time an adjacent neuron fires. When there is a build up of PSPs, we can measure their group activity butthese neurons need to be in sync with one another.Invasive EEGs are relatively big electrodes sitting on the cerebrum and measures synchronous changing voltage of hundreds/thousands of neurons. Single/multi-unit cell recordings, invasive EEG, are invasive. They are mostly done in vitro or require invasive surgery. Stereotaxic surgery is a method used to implant devices or manipulate small brain regions of a living organism. In humans, individuals that have an important medical reason to have electrodes implanted can in their heads.EEG: measure electrical activity generated by the brain and conducted to the scalp.Techniques to measure PNS  EMG, SCL/SCR, EKG/ECGNoninvasive brain measuresMRI  gives the highest spatial resolution. 1 slice of MRI is made up of a thin layer of many voxels. Each voxel contains a combo of atoms and compounds that have their own electromagnetic properties. Imaging brain function  positron emission tomography (PET), fMRI, multi-modal imagingInterfering with brain function  aspiration, knife cuts, heat, cryogenic blockage, transcranial magnetic stimulationResearch designSample: subset of the population of interest Independent variable: variable that is going to be alteredDependent variable: variable that will be measuredConfounding variables: variables that confuse our resultsWithin subjects design: comparing conditions within a single group of subjectsBetween subjects: comparing multiple groups based on researcher designated conditionsSensation and perceptionExteroceptive pertains to external stimulation  audition, somatosensory, olfaction, gustation, and visionSensation: process of detecting the presence of a stimuliPerception: process of consciously recognizing and interpreting a sensationSensory information climbs a hierarchy  receptors > thalamic relay nuclei > primary sensory cortex > secondary sensory cortex > association cortexSomatosensation refers to the process of detecting changes in pressure, skin stretch, vibration, and temperature on places on the body. The structure of a receptor cell enables it to respond specifically to certain stimuli slowly or quickly. The first step of sensation is transduction. Ipsilateral and contralateral to denote which side of the body sensory info came from and whichside of the brain it affects. Ipsi means same side of the body. Contra means opposite. Most sensory and motor pathways are laid out this way. Primary sensory cortex is organized somatotopically. The somatosensory cortex is located in the parietal lobe. Motor cortex is located in the frontal lobe and is separated by the central sulcus. Receptive field: region in space where contact with a stimulus will alter the activity of a given sensory neuronAuditionNot all receptive fields are defined by space. Primary auditory cortex has neurons with receptivefields in auditory frequencies. Pure tones consists of only one frequency, pure tones rarely exist in nature. Ear is an analytic organ that decomposes a single complex sound into multiple simpler sounds.Vision3 pairs of extraocular muscles aim the eyeBinocular disparity: difference in location seen by right and left eyes  important cue for how far or near an object isLight bends through the cornea  focused by the lens  pupil governs how much light is let in  ciliary muscles stress/compress the lens to change focusPhototransduction takes place in the retinaPhotoreceptors  rods and cones  Rods are highly sensitive to light (important for low light vision), cones enable high acuity and color visionVisual fields are determined by the nasal (medial) and temporal (lateral) hemiretinasThe optic chiasm sorts axons from the right visual field to the left hemisphere of the brain and vice versa.The retina-geniculate-striate pathway is organized