1. The Nervous System and the Brain - Additional info
Higher Human Biology
Subtopic 17
Brain Studies

2. Learning Intentions To discuss how to measure brain activity
To discuss split brain studies
**Related topics – pages 218 – 222 ***

3. Test your brain……
The Big Page of Brain Teasers

4. Study of the brain
Studying the workings of the brain is very difficult - we still know very little detail about brain function.
What we do know comes from studying
Patients with brain injury
EEG's
Brain scans
Split brain studies

5. Brain injury evidence
A lot of information – especially during the early years of brain study – came from the study of accidental injury or from damage due to disease :
Tumour
Lesions
Shrapnel injuries
Strokes

6. Phineas Gage

7. EEG's An EEG – electroencephalogram
– records the electrical activity or BRAINWAVES by means of electrodes placed upon the scalp.

8. EEG'S
Brain wave patterns are generated – different for different levels of brain activity.
Used in various ways but fail to pinpoint the area of the brain in which the activity is taking place.

10. Brain scans
Various brain imaging methods allow neuroscientists to 'see' inside the living brain.
All methods are useful as they provide clear, visual images of brain activity.

11. Split-brain studies
Studies of patients with damage to the corpus callosum allow investigation into the affect of the cerebral hemispheres not transferring information between each other.
Most well known studies have investigated visual pathways.

12. Visual pathway study Normal brain will perceive the field of view.
Each eye detects light from both sides but each CH receives HALF of the information from each eye because half of the optic nerve fibres cross to the opposite hemisphere at the optic chiasma.
Transfer of information bewteen hemispheres means whole field of view is percieved.

14. Visual pathway study
Abnormal brain will NOT perceive the actual field of view.
Each eye still receives the same sensory information but since information is not transferred between the hemispheres each CH receives only half of the information.

15. Read the notes below for an explanation……
Look at the dot in the middle.
What would you see if your left CH was damaged?
In this figure, the face on the left is a woman and the face on the right is a man. Therefore, if the patient focuses on the dot in the middle of the forehead, the visual information about the woman's face will go to the right cerebral hemisphere and information about the man's face will go to the left hemisphere. When a split brain patient is asked to point to a whole, normal picture of the face that was just seen, the patient will usually pick out the woman's picture (remember, the information about the woman's face went to the RIGHT cerebral hemisphere). However, if the patient is required to say whether the picture was a man or a woman, the patient will SAY that the picture was of a man. Therefore, depending on what the patient is required to do, either the right or left hemisphere will dominate. In this case, when speech is not required, the right hemisphere will dominate for recognition of faces.
Read the notes below for an explanation……

16. Have a think about which CH is processing each piece of info…..

17. Learning Intentions To discuss how to measure brain activity
To discuss split brain studies
**Related topics – pages 218 – 222 ***