Textbook Notes (363,185)
Canada (158,247)
Psychology (9,573)
PSYB65H3 (479)
Ted Petit (185)
Chapter 3

PSYB65 Chapter 3.docx

5 Pages
Unlock Document

University of Toronto Scarborough
Ted Petit

Chapter 3: Foundations of Neuropsychology Study of the Damaged Nervous System The Scientific Method • Empirical method o Level of objectivity o Associated with replication of the results so that they can be confirmed • Converging operations o Common conclusion is reached by examining a number of studies that approach the question from a variety of different perspectives NonhumanAnimal Models • Nonhuman animals that are raised in controlled conditions afford the researcher greater control o Using nonhuman animal that have been raised in controlled conditions reduces the variability that is attributable to extraneous factors • Delayed nonmatching to sample task o Involves a food reward and a food-deprived nonhuman animal • Limitations: o Differences between humans and nonhuman models  Difference in the complexity of the CNS o Some topics may not be suitable Cognitive Testing • Detailed examination of higher cognitive functions • Begins with a personal interview that is followed by a series of tests o Standardized cognitive tests o Some tests may have problems with generalization beyond the sample with which they were developed Brain Imaging • Problem: there is no average brain Structural Imaging X-Rays • The more dense the material, the less penetrable the substance is to X-rays o Makes X-rays useful for medical imaging Computed Tomography (CT) • First good means available to noninvasively image live brain tissue • Highly dense areas appear bright, lower density areas appear relatively dark • Differentiation between white and gray matter is rather poor • Painless, takes relatively little time and can be performed on an unconscious individual • Axial plane is also the horizontal plane and refers to images being constructed in one plane • Coronal plane shows slices perpendicular to the horizon, taken along the superior-inferior axis • Sagittal plane has images that are also perpendicular to the horizon, but they are taken along the dorsal- ventral axis • CT scans are useful for both research and clinical applications o For clinical purposes, they help to identify anatomical abnormalities or acquired injuries  Provided that these changes are reflected in changes in tissue density Magnetic Resonance Imaging (MRI) • Superior resolution o CT scanners still preferable in some situations • Relaxation time o MRI machine measures the time taken by the atoms to return to their normal, random state that follows the pulse • Receiver coil o Measures the information about the intensity of the signal, but the spatial information is provided from variations in the gradient field over the imaged area  Combination of these two types of information allows the construction of 3D images of the brain • Representations of hydrogen density • Relaxation time can reflect the return to a random state along the longitudinal axis or along the horizontal plane • Different substances relax at different rates along these dimensions o The type of relaxation that one chooses to image depends on what one is looking for • Can use extremely strong magnets, and their magnetic strength can be measured in units of Tesla (T) • Considered non-invasive o Not 100% safe  Eg. Metallic, magnetic aneurysm clip, heart pacemakers are incompatible Electrophysiological Methods • Measuring the electrical and/or magnetic currents that are generated by brain activity • Weakness of most electrophysiological methods are strengths of most other functional imaging methods, and vice versa Electroencephalogram (EEG) • Berger discovered regular waves and termed it alpha waves (8-13 Hz) o Beta waves refers to activity faster than 13 Hz, theta waves are relatively slow at 4-8 Hz and delta waves are slowest at <4 Hz • Include descriptions of synchronization or desynchronization between analogous sites • Output read in qualitative manner o Look for abnormal patterns of activity at one or more of the recording sites • Quantitative EEG methods rely on computers to analyze the incoming data • Recent developments led to the spatial mapping of the source of electrical signals in EEG signal based on mathematical models • Greatest EEG technology can only localize activity within approximately 1 cm and the accuracy of the localization decreases as the focus gets farther away from the scalp Event-Related Potentials (ERPs) • Procedure very similar to recording EEGs • Use mostly the same equipment, and the measurement from the scalp is the same: small changes in electricity activity • Single biggest difference is that in an EEG, person being recorded typically is not presented with any stimulation or cognitive task o Recordings taken while the person is at rest, measuring idling brain o Alot of background noise in the record, so difficult/impossible to observe noise • ERP attempts to solve issue of noise o Stimulus is presented repeatedly while EEG is recorded o Does not look much different from one without a stimulus  There is average difference that follows the stimulation • Characteristic, slow waveform usually emerges • Event-related or evoke responses that last for less than 1 second after presentation of the stimulus o Waveform components have two types:  Exogenous components • Associated with the physical characteristics of the stimulus • Altering the stimulus presented should alter the exogenous components of the waveform  Endogenous components • Less dependent on the physical nature of the stimulus • Appear to be determined largely by the cognitive task or context in which the stimuli are presented • Typically later in the waveform – after initial sensation and perception of the stimulus o Distinction between endogenous and exogenous components of the waveforms is not always clear  Source of the waveforms is often quite difficult to localize  Technique good for studying relatively fast cognitive processes • Eg.Attention and memory  Helpful for diagnosing conditions such as multiple sclerosis Magnetoencephalog
More Less

Related notes for PSYB65H3

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.