RESEARCH METHODS IN BIOPSYCHOLOGY LECTURE NOTES Based on

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

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

BEHAVIORAL METHODS IN BIOPSYCHOLOGY l l l Neuropsychological Testing Behavioral Methods in Cognitive Neuroscience Animal Behavior Paradigms

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

CT SCANS l l l A computer assisted X-ray procedure An X-ray scanner is rotated 1 o 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.

MRI SCANS l l 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.

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

PET SCANS l l 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.

PET Versus CAT l l 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.

FUNCTIONAL MRI l l l 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 f. MRI methods: http: //www. fmri. org/fmri. htm

Magnetoencephalography (MEG) l l MEG measures changes in magnetic fields on the scalp surface that are produced by changes in patterns of neural activity. Advantage over f. MRI – l Advantage over EEG – l faster temporal resolution 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

Transcranial Magnetic Stimulation l 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.

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

INVASIVE PHYSIOLOGICAL METHODS IN NONHUMANS l l Stereotaxic Surgery Lesion Methods Electrical Stimulation Electrophysiological Recording

LESIONING TECHNIQUES l l l Aspiration lesions Radio-frequency lesions Knife cuts Cryogenic blockade Chemical Lesions

NEUROHISTOLOGY TECHNIQUES l l 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

NEUROHISTOLOGICAL STAINING TECHNIQUES l Nissl Stains – – l Golgi Silver Stain – l e. g. , cresyl violet stains mainly cell bodies stains whole neurons Myelin Stains (Fiber stains) – – e. g. , Weigert stains mainly myelin For more information on neurohistological stains, visit: http: //education. vetmed. vt. edu/Curriculum/VM 8054/Labs/Lab 9. htm Brain images obtained from http: //www. brainmuseum. org

ELECTROPHYSIOLOGY TECHNIQUES l l l Intracellular unit recording Extracellular unit recording Multiple-unit recording – See page 114 in Pinel

NEUROPHARMACOLOGICAL METHODS Measuring Chemical Activity in the Brain l 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. l e. g. , see page 115 in Pinel

NEUROPHARMACOLOGICAL METHODS l 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)

NEUROPHARMACOLOGICAL METHODS Localizing Neurotransmitters and Receptors l l 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 m. RNA are artificially created and labeled with a dye or radioactive element – Brain tissue slices are exposed to solution containing the labeled m. RNA – Brain slices are viewed under microscope to identify regions where the m. RNA expression is highest l e. g. , see page 117 in Pinel

GENETIC ENGINEERING l Gene Knockout Techniques – – Creating organisms lacking certain genes Limitations regarding interpretation of knockout effects l l 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 l l Experience influences gene expression, so effects of knockout may interact with experience in complex ways Gene Replacement Techniques – Creating transgenic organisms l e. g. inserting human genetic material into mice

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

ANIMAL BEHAVIOR PARADIGMS l Common Learning Paradigms – – – Conditioned Taste Aversion Conditioned Escape/Avoidance Conditioned Place Preference Radial Arm Maze Morris Water Maze

Operant Conditioning Apparatus

Conditioned Place Preference Apparatus

Radial Arm Maze

Open Field Apparatus