AP PSYCHOLOGY: UNIT II Introductory Psychology: Biological Bases of Behavior Topic: Research Methods

PART ONE Research Methods: Lesioning

Methods: Lesioning Lesioning  The natural or experimental destruction of brain tissue  An electrode passes a high frequency current through the structure  Burns & disables the targeted tissue  Use?  Victims of severe brain injury  Parkinson’s patients? Schizophrenic patients? OCD patients?

Methods: Lesioning

PART TWO Research Methods: Electrical Recordings Hans Berger German Psychiatrist 1929

Research: Electrical Recordings Electroencephalograph (EEG)  Monitors brainwave patterns produced by electrical activity on the surface of the brain  EEG electrodes amplify electric potential  Use?  Sleep stages  Seizure disorders  Presence of tumors  Active areas of brain

PART THREE Research Methods: Electrical Stimulation

Methods: Electrical Stimulation Electrical Stimulation of the Brain (ESB)  A process in which a weak electrical current is sent into a brain structure in order to stimulate it  Delivered by an electrode  Simulates normal signals in the brain & activates the structure in question  Use?  Animal research  Humans in some surgical situations

PART FOUR Research Methods: Transcranial Stimulation

Methods: Transcranial Stimulation Transcranial Magnetic Stimulation (TMS)  New technique  Permits scientists to temporarily enhance or depress activity in a specific area of the brain; 2 cm  “Virtual lesions”  Limitations?

PART FIVE Research Methods: Brain-Imaging Procedures

Methods: Brain-Imaging Computer Tomography (CT)  Brain-imaging method that utilizes computer- controlled x-rays of the brain; gives a composite representation (map) of brain slices  Use?  Stroke damage  Blood clots  Tumors  Injuries  Abnormal brain structure

Methods: Brain-Imaging Positron Emission Tomography (PET)  Brain-imaging method is which a radioactive glucose is injected into the subject  A computer compiles color-coded images of brain activity, with lighter colors indicating more activity

Very high activity High activity Medium activity Low activity No activity

Methods: Brain-Imaging

Magnetic Resonance Imaging (MRI)  A technique that uses magnetic fields and radioactive waves to produce computer generated images that distinguish among different types of soft tissue  Allows us to see smaller details & structures within the brain

Methods: Brain-Imaging CT versus MRI?  Cost  CTs are generally less expensive than MRIs  Testing Ability  CTs are less sensitive to patient movement  CT scans CAN be performed in the presence of an implanted medical device  Side Effects  MRI contrast materials used for image enhancement have very low incidence of side effects

Methods: Brain-Imaging Functional MRI (fMRI)  A new variation on MRI technology that monitors blood flow and oxygen consumption in the brain to identify areas of high activity  As opposed to a traditional MRI, the fMRI allows neuroscientists to study brain ACTIVITY