RESEARCH METHODS IN BIOPSYCHOLOGY

1. RESEARCH METHODS IN BIOPSYCHOLOGY LECTURE NOTES Based on Pinel, Chapter 5

2. METHODS TO STUDY THE NERVOUS SYSTEM • Brain Imaging & Brain Stimulation Techniques in Living Humans • Psychophysiological Techniques • Invasive Physiological Methods • Neuropharmacological Methods • Genetic Engineering

3. BEHAVIORAL METHODS IN BIOPSYCHOLOGY • Neuropsychological Testing • Behavioral Methods in Cognitive Neuroscience • Animal Behavior Paradigms

4. IMAGING & STIMULATING THE LIVING BRAIN • Contrast X-rays • cerebral angiography • Computed Tomography (CT) • Magnetic Resonance Imaging (MRI) • Positron Emission Tomography (PET) • Functional MRI (fMRI) • Magnetoencephalography (MEG) • Transcranial Magnetic Stimulation (TMS)

5. A computer assisted X-ray procedure An X-ray scanner is rotated 1o at a time over 180 o Computer reconstruction Horizontal sections Reveal structural abnormalities, such as cortical atrophy or lesions caused by a stroke or trauma. CT SCANS

6. MRI SCANS • A strong magnetic field causes hydrogen atoms to align in the same orientation. • When a radio frequency wave is passed through the head, atomic nuclei emit electromagnetic energy. • The MRI scanner is tuned to detect radiation emitted from the hydrogen molecules. • Computer reconstructs image.

7. Advantages of MRI No ionizing radiation exposure Better spatial resolution Horizontal, Frontal or Sagittal planes Disadvantages Cost No ferrous metal! MRI VS. CT SCANS

8. PET SCANS • A positron emitting radionuclide is injected (e.g., 2-deoxyglucose). • Positrons interact with electrons which produce photons (gamma rays) traveling in opposite directions. • PET scanner detects the photons. • Computer determines how many gamma rays from a particular region and a map is made showing areas of high to low activity.

9. PET Versus CAT • CAT scans show brain structures. • PET scans reveal brain activity. • CAT involves absorption of X-rays. • PET involves emission of radiation by an injected or inhaled isotope.

10. FUNCTIONAL MRI • Images brain hemodynamics. • Advantages over PET: • No injections need to be given • Structure and Function • Shorter imaging time • Better spatial resolution • 3-D images • Check out this website for more info on fMRI methods: http://www.fmri.org/fmri.htm

11. Magnetoencephalography (MEG) • MEG measures changes in magnetic fields on the scalp surface that are produced by changes in patterns of neural activity. • Advantage over fMRI • faster temporal resolution • Advantage over EEG • greater accuracy and more reliable localization due to minimal distortion of the signal • Clinical Uses • Evaluation of epilepsy: to localize the source of epileptiform brain activity, usually performed with simultaneous EEG

12. Transcranial Magnetic Stimulation • TMS disrupts neural activity by creating a magnetic field under a coil positioned near the skull. • Disruption of specific cortical locations are produced while participants engage in cognitive and/or behavioral tasks. • This allows researchers to assess functions of specific cortical areas.

13. PSYCHOPHYSIOLOGY • Electroencephalography (EEG) • Electromyography (EMG) • Electrooculography (EOG) • Electrodermal activity (Skin Conductance) • Cardiovascular activity • Heart rate (EKG) • Blood Pressure • Plethysmography

14. INVASIVE PHYSIOLOGICAL METHODS IN NONHUMANS • Stereotaxic Surgery • Lesion Methods • Electrical Stimulation • Electrophysiological Recording

15. LESIONING TECHNIQUES • Aspiration lesions • Radio-frequency lesions • Knife cuts • Cryogenic blockade • Chemical Lesions

16. NEUROHISTOLOGY TECHNIQUES • Fixation, preservation of tissue, sectioning and staining of tissue • Uses of histological techniques • Confirming lesion sites or electrode locations • In combination with neural tracing techniques (anterograde, retrograde labeling) • In combination with autoradiography or immunohistochemistry techniques

17. NEUROHISTOLOGICAL STAINING TECHNIQUES • Nissl Stains • e.g., cresyl violet • stains mainly cell bodies • Golgi Silver Stain • stains whole neurons • Myelin Stains (Fiber stains) • e.g., Weigert stain • stains mainly myelin For more information on neurohistological stains, visit: http://education.vetmed.vt.edu/Curriculum/VM8054/Labs/Lab9/Lab9.htm Brain images obtained from http://www.brainmuseum.org

18. ELECTROPHYSIOLOGY TECHNIQUES • Intracellular unit recording • Extracellular unit recording • Multiple-unit recording • See page 114 in Pinel

19. NEUROPHARMACOLOGICAL METHODSMeasuring Chemical Activity in the Brain • 2-DG Autoradiography • Radioactive 2-deoxyglucose is injected • Animal engages in behavior of interest • Animal is euthanized, brain tissue is removed and sliced • Tissue slices are coated with photographic emulsion and stored in the dark (much like film processing) • Areas that absorbed high levels of radioactive substance will appear darker • Using computer imaging, differences in density can be color coded. • e.g., see page 115 in Pinel

20. NEUROPHARMACOLOGICAL METHODS • Cerebral Dialysis (in vivo microdialysis) • Under anesthesia and stereotaxic guidance, a cannula is inserted into a specific brain site. • Following recovery, a small probe with a semipermeable membrane is inserted into the cannula. • Fluid is perfused through the probe and chemicals in the extracellular fluid diffuse across the membrane and are collected into a sample vial. • The samples are then analyzed using a chromatography methods. (e.g. HPLC)

21. NEUROPHARMACOLOGICAL METHODSLocalizing Neurotransmitters and Receptors • Immunocytochemistry • Makes use of antibodies for specific proteins, such as receptors or enzymes. • The antibody is labeled with a fluorescent die or a radioactive element (commercially available). • Brain tissue is sliced and exposed to a solution containing the labeled antibody. • Brain slices are viewed under microscope to identify the regions where protein of interest is distributed. • In situ hybridization • Also used to locate peptides or proteins in tissue • Hybrid strands of mRNA are artificially created and labeled with a dye or radioactive element • Brain tissue slices are exposed to solution containing the labeled mRNA • Brain slices are viewed under microscope to identify regions where the mRNA expression is highest • e.g., see page 117 in Pinel

22. GENETIC ENGINEERING • Gene Knockout Techniques • Creating organisms lacking certain genes • Limitations regarding interpretation of knockout effects • Most behavioral traits are influenced by the activities of multiple genes • Elimination of a gene may modify the expression of other genes • Effects of gene knockout may be masked by compensatory changes to other genes • Experience influences gene expression, so effects of knockout may interact with experience in complex ways • Gene Replacement Techniques • Creating transgenic organisms • e.g. inserting human genetic material into mice

23. ANIMAL BEHAVIOR PARADIGMS • Species-common behaviors • Aggressive Behaviors • Defensive Behaviors (e.g., anxiety paradigms) • Reproductive Behaviors • Locomotor Activity • Traditional Conditioning Paradigms • Pavlovian (Classical) Conditioning • Operant Conditioning

24. ANIMAL BEHAVIOR PARADIGMS • Common Learning Paradigms • Conditioned Taste Aversion • Conditioned Escape/Avoidance • Conditioned Place Preference • Radial Arm Maze • Morris Water Maze

25. Operant Conditioning Apparatus

26. Conditioned Place Preference Apparatus

27. Radial Arm Maze

28. Open Field Apparatus