AP Psychology Sept. 16th Objective Opener Identify the purposes for different methods of measuring the brain. Understand the importance of the corpus collosem and the difference between the left and right brain by participating in a demonstration. Presentations

Electroencephalogram EEG Detects brain waves through their electrical output. Used mainly in sleep research.

Magnetic Resonance Imaging MRI More detailed picture of brain using magnetic field to knock electrons off axis. Takes many still pictures and turns images into a movie like production. 3D MRI

Computerized Axial Tomography CAT Scan 3D X-Ray of the brain. Good for tumor locating, but tells us nothing about function.

Positron Emission Tomography PET Scan Measures how much of a chemical the brain is using (usually glucose consumption).

Functional MRI Combination of PET and MRI

Hemispheres Divided into to hemispheres. Contralateral control: right controls left and vice versa. In general, Left Hemisphere: logic and sequential tasks. Right Hemisphere: spatial and creative tasks.

The Corpus Callosum Divides the 2 hemispheres.

Split Brain Patients Those who dues to epilepsy, have their corpus callosum removed.

Testing the Divided Brain

Split-Brain Surgery- Severe Epilepsy Corpus Callosum attaches the two hemispheres of cerebral cortex. When severed you have a split- brain patient. Michael Gazzaniga & Roger Sperry studied these split-brain patients

Split Brain Demo Was this task difficult or easy? Why? VOLUNTEERS: Tie the shoe with only the hand you have on the desk. Right Hemisphere=left hand Left Hemisphere=right hand Difficult b/c: The volunteers are trying to coordinate the movements of 2 independent hands. Split brain patients experience some numbness & coordination problems immediately after surgery Practice & Habituation will improve performance over time.

Split Brain Demo ENTIRE CLASS: Draw each shape with the assigned hand at the same time SPLIT BRAIN PATIENT: Now you give it a try….

Split Brain Demo Was this task easier for the split brain patient or the people with “normal” brains? Why? EASIER FOR THE SPLIT BRAIN PATIENT b/c of the disconnect between the two hemispheres – each hemisphere sees something different & can operate independently to draw it with ease.

Left Hemisphere (right hand)– wear the blinders & look down at the paper & pen in front of you (NO PEAKING!) Right Hemisphere (left hand)– take the pen in hand…draw a picture of what’s on the flashcard. Why can’t the left hemisphere answer initially? Why can’t the Right Hemisphere answer verbally? What is on the card??? Left Hemisphere = Language center The right Hemisphere is unable to SAY what he saw but he can draw it. B/C the Right Hemisphere “saw” the card...but the Right Hemisphere can’t share that info with the Left Hemisphere internally (No Corpus Callosum) The Left Hemisphere literally doesn’t know what was on the card until he sees it drawn in front of them…with his own left hand by the right hemisphere! https://www.youtube.com/watch?v=lfGwsAdS9Dc

Living with half a brain

Neural Plasticity The brain has the ability to be changed by experience. Rosenzweig (1984) demonstrated the importance of experience to neural development Rats raised in more complex environments had larger neurons and more synaptic connections. Other research has found those rats raised in more complex environments are better at solving problems The brain changes in response to experience. This appears to happen as a response to expertise (e.g. practicing the violin) Neural plasticity The ability of the brain to be changed structurally and chemically by experience. Rosenzweig (1984) demonstrated the importance of experience to neural development Rats raised in more complex environments had larger neurons and more synaptic connections Other research has found those rats raised in more complex environments are better at solving problems The brain changes in response to experience. This appears to happen as a response to expertise (e.g. practicing the violin) The strength of the response varies as well as the amount. Adult brains are capable of neurogenesis, the creation of neurons over the course of one’s lifetime This finding has lead to new research into the potential to grow cells to replace damaged cells, or finding ways to encourage damaged cells to repair themselves. Morris, (c) 2006, Prentice Hall

Brain Plasticity The idea that the brain, when damaged, will attempt to find news ways to reroute messages. Children’s brains are more plastic than adults.

Homework Review Watch Crash Course #3-4 and complete viewing guides.