PSY 0505 LECTURE OBJECTIVES AND OUTLINE Spring 2014 LECTURE METHODOLOGY Objectives Terms and concepts to learn contrast x ray cerebral angiography computed tomography CT positron emission tomography PET magnetic resonance imaging MRI functional MRI fMRI electroencephalograph EEG electromyogram EMG electrooculogram EOG electrocardiogram ECG knife cut lesion aspiration lesion radio frequency lesion neurotoxin lesion excitotoxic cryogenic blockade neural stimulation Outline I INTRODUCTION a We are not responsible for physiological tests not on exam but we will be looking for physical tests and scans that can be done of the brain II METHODOLOGY A Brain Visualization a one big method can be contrast e rays were basically photograph brain with x ray technology to get image of various structures and densities as appear shaded on x ray i problem is that no bones mostly soft tissue in brain so some dye substance must e injected into bloodstream to provide shading for the x ray radio opaque kind of dye that as circulates in vessels in brain will allow for visualization for particular damage structural changes 1 in hemorrhagic stroke aneurism that starts to bleed in brain we will have leaching out spreading of dye into larger areas of brain beyond where the capillaries should be to indicate bleeding in brain broken vessels 2 can also be used to identify tumors which grow very fast so will have many capillaries and blood vessels densely packed in that given area more radio opaque dye in one area that indicates and anomaly ii contrast x rays used to notice structural changes physical changes can even tell where a clot may be as dye will not go past this point as compared to a control average brain 1 cerebral angiography 2 CT scan computer tomography also based on x ray of brain but enhanced by ability to piece together certain sections of brain and get more of a 3 D representation of the area on interest 6 to 8 sections are being scanned as person goes through machine so we look at horizontal scans of top to bottom of the head and computer gives much better impression of brain a still not very high resolution and shows simple structural changes for global identification of problems such as a clot or aneurism that has not yet burst balloon and squash surrounding tissue and contusions concussions from traumatic injuries that appear as darker spot on scan and can look for tumors that have a different density to rest of brain tissue surrounding it 3 PET scan positron emission where 2 dioxy glucose injected in to carotid artery and is similar to glucose in structure so also absorbed and passed on from the astrocyte to neuron but is not metabolized and stays in system for a short time before just being flushed out and eliminated from body but radioactive so can be detected in different parts of nervous system a colors seem in PET scan indicate levels of activity in brain where red high and blue low as when neurons fire need more energy glucose so astrocytes that support these neurons absorb more glucose and higher levels absorption 2 deoxy glucose seem in high activity areas b put person in scanner and show them images and when look at something focus on it the visual cortex in occipital lobe is highlighted when auditory signal shown temporal lobe primary auditory cortex is primarily activated associated areas are coming on to activated by sound motor activities show activation in areas of motor cortex c gives different information then is seem on structural scans and perhaps neurons are not functioning gas they should but are still present no lesion dead neurons dead space to show in structure scans so PET scan shows us if particular area of brain is not responding the way t should function can be changed and we determine this but no way of knowing if there is a physical problem 4 MRI scan magnetic resonance imagine revolutionized medicine as provides much higher resolution so this is why it is favored over other scans and is set up to place individual within very strong magnetic field which then operates on brain and hydrogen atoms in body begin to give of particular wave pattern that computer then reads as a structure of the detailed bits of brain a very detailed structural scan not for function that can scan in any direction wanted but can disrupt pacemakers and heat nearby metal forcing patients to be checked well before test 5 fMRI scan functional MRI is very much like MRI but allows for visualization of both structure and function where again a person is placed in a strong magnetic field where structure is imaged using waves emitted y hydrogen atoms fro structure and in addition looks for signal changes in oxygen interaction between oxygen and iron in blood allows to see changes in activity in various parts of brain a much more ability in one scan to look at structure and function B Psychophysiological Activity less expensive but just as useful to do 1 EEG electroencephalogram is a series of electrodes that are spaces all along the skull typically attached to cap placed on head and is a measure of general to specific but regional activity a measures shifts of EPSPs IPSPs and action potentials electrical pulse shifts within neurons and often used to measure brain waves in sleep high fast shifts means person awake aroused and thinking relaxed person who is zoned out day dreaming sees larger shifts in wave yet smaller less frequent fluctuation just fallen asleep deep sleep b often used in epilepsy to see where there is a start of the seizure to then target treatment to that particular brain area 2 EOG electrooculogram monitors changes in electrical potential between the front and back of eyeball electrodes placed around eye socket to record any eye movements and changes especially in REM sleep sleep studies again a rapid eye movement REM sleep has ayes dart around when we are dreaming and this monitors when we enter and leave REM sleep 3 EMG electromyogram is a measure of muscle tension that occurs under the skin and is a technique where electrodes placed around particular muscle groups wraps around arm leg abdomen and get signal from all neurons as a big fuzzy raw signal a an integrates signal then is a single neurons activity b also used to monitor sleep when placed on neck chin and jaw of person as particular muscles tend to relax as you fall asleep and a loss of muscle tone means that we are in REM sleep minimal contraction in all body C Invasive Techniques mostly used for research