1. How can we study the brain?

2. Scanning the Brain Do This: 66-69
Read through the descriptions of the different types of brain scans
Rank the scans in order of most useful and least useful
Provide an example to help explain your ranking choices

3. Brain Scans 66-69 Method How it works Used for CAT or CT scans
Computerized axial tomography
PET scan
Positron emission tomography
MRI scan
Magnetic Resonance Imagine
EEG
Electroencephalogram

4. Brain Scans Method How it works Used for CAT or CT scans
Computerized axial tomography
Fancy x-ray
Several xrays around the brain for a 3D picture
Shows structure but not function or activity of the brain
PET scan
Positron emission tomography
Measures chemical usage in the brain
Measures brain activity
Can scan for different chemicals, neurotransmitters, and blood flow
MRI scan
Magnetic Resonance Imagine
Uses magnetic fields to measure the density and location of brain material
Shows structure and not function (fMRI uses PET type scan to combine structure and function)
Indicates damage
Does not expose patient to radiation like an xray
EEG
Electroencephalogram
Device detects brain waves
Researchers can see the type of waves the brain produces during different stages of consciousness
Study activity and function

5. Techniques for Studying Human Brain Function and Structure

6. EEG (Electroencephalography)
Technique: Multiple electrodes are pasted to outside of head
What it shows: A single line that charts the summated electrical fields resulting from the activity of billions of neurons

7. EEG (Electroencephalogram)
Advantages
Detects very rapid changes in electrical activity, allowing analysis of stages of cognitive activity
Disadvantages
Provides poor spatial resolution of source of electrical activity

8. PET (Positron Emission Tomography) SPECT (Single Photon Emission Computed Tomography)
Technique: Positrons and photons are emissions from radioactive substances
What it shows: An image of the amount and localization of any molecules that can be injected in radioactive form, such as neurotransmitters, drugs, tracers for blood flow or glucose use (which indicates specific changes in neuronal activity)
PET Scan

9. PET (Positron Emission Tomography) SPECT (Single Photon Emission Computed Tomography)
Advantages
Allows functional and biochemical studies
Provides visual image corresponding to anatomy
Disadvantages
Requires exposure to low levels of radioactivity
Provides spatial resolution better than that of EEG, but poorer than that of MRI
Cannot follow rapid changes (faster than 30 seconds)

10. MRI (Magnetic Resonance Imaging)
Technique: Exposes the brain to magnetic field and measures radio frequency waves
What it shows: Traditional MRI provides high resolution image of brain anatomy, and newer functional images of changes in blood flow (which indicate specific changes in neuronal activity)

11. Advantages of MRI Requires no exposure to radioactivity
Provides high spatial resolution of anatomical details (<1 mm)
Provides high temporal resolution (<1/10 of a second)

12. fMRI-Functional MRI
Functional magnetic resonance imaging, or fMRI, is a technique for measuring brain activity. It works by detecting the changes in blood oxygenation and flow that occur in response to neural activity – when a brain area is more active it consumes more oxygen and to meet this increased demand blood flow increases to the active area. fMRI can be used to produce activation maps showing which parts of the brain are involved in a particular mental process.

13. MEG (Magnetoencephalography)
What it shows: Detects the magnetic fields produced by electrical currents in neurons
Detects and localizes brain activity, usually combined with structural image from MRI
Advantages
Detects very rapid changes in electrical activity, allowing analysis of stages of cognitive activity

14. MEG (Magnetoencephalography)
Advantages (cont.)
Allows millimeter resolution of electrical activity for surface sources such as cerebral cortex
Disadvantages
Poor spatial resolution of brain activity in structures below cortex
Equipment is very expensive

15. Scanning the Brain Do This: 66-69
Read through the descriptions of the different types of brain scans
Rank the scans in order of most useful and least useful
Provide an example to help explain your ranking choices

16. Questions
1) Blindness could result from damage to which cortex and lobe of the brain?
Visual cortex in the frontal lobe
Visual cortex in the temporal lobe
Sensory cortex in the parietal lobe
Visual cortex in the occipital lobe
Cerebral cortex in the occipital lobe

17. answer
1) D visual cortex in the occipital lobe

18. Question
Paralysis of the left arm might be explained by a problem in the
A) motor cortex in the frontal lobe in the left hemisphere
B) motor cortex in the frontal lobe in the right hemisphere
C) sensorimotor cortex in the temporal lobe in the left hemisphere
D) motor cortex in the parietal lobe in the left hemisphere
E) motor cortex in the occipital lobe in the right hemisphere

19. answer
2) B motor cortex in the frontal lobe in the right hemisphere

20. question
Which chemicals pass across the synaptic gap and increase the possibility the next neuron in the chain will fire?
Synaptic peptides
Inhibitory neurotransmitters
Adrenaline – type exciters
Excitatory neurotransmitters
Potassium and sodium

21. answer
3) D Excitatory neurotransmitters

22. question Which sentence most closely describes neural transmission?
An electric charge is created in the neuron, the charge travels down the cell, and chemicals are released that cross the synapse to the next cell.
A chemical change occurs within the cell, the change causes an electric charge to be produced, and the charge jumps the gap between the nerve cells.
The electric charge produced chemically inside a group of neurons causes chemical changes in surrounding cells.
Neurotransmitters produced in the hindbrain are transmitted to the forebrain, causing electric changes in the cerebral cortex.
Neural transmission is an electrochemical process both inside and outside the cell

23. answer
4) An electric charge is created in the neuron, the charge travels down the cell, and chemicals are released that cross the synapse to the next cell.

24. question
Dr. Fuller, a brain researcher, is investigating the connection between certain environmental stimuli and brain processes. Which types of brain scans is he most likely to use?
MRI and CAT
CAT and EKG
PET and EEG
EKG and CAT
Lesioning and MRI

25. answer
C) PET and EEG