1. 1 Psychology 304: Brain and Behaviour Lecture 4

2. 2 Research Methods and The Structure of the Nervous System 2. What are the primary divisions of the nervous system? 1.How do biological psychologists assess the structure and function of the nervous system? (continued)

3. 3 By the end of today’s class, you should be able to: 1. discuss the goals and methods of EEG, MEG, and electrical stimulation. 2. describe lesioning techniques. 3. distinguish between the central and peripheral nervous systems.

4. 4 4. Recording  Allows researchers to record the electrical and magnetic output of the living brain.  Examples:  The small electrical charges and magnetic fields that nerve cells generate are measured using electrodes. How do biological psychologists assess the structure and function of the nervous system?

5. 5 Electroencephalography (EEG): Electrodes, placed on the scalp, measure the electrical activity of a large number of nerve cells. Changes in EEG signals that are elicited by the presentation of sensory stimuli are referred to as sensory evoked potentials. Provides a measure of brain activity.

6. 6 EEG Recordings Associated with Wakefulness and Sleep Beta waves (15-20 Hz) Alpha waves (8-12 Hz) Delta waves (1 Hz)

7. 7 Image 1 Image 2 Image 3 EEG Recordings for Comatose Patients

8. 8 Magnetoencephalography (MEG): A recording technique in which magnetic sensors (SQUIDs) are placed on the scalp. The sensors measure the magnetic activity of a large number of nerve cells. Provides a measure of brain activity.

9. 9 MEG Recording and Plot on 3D Image of Participant’s Head Presentation of visual stimulus

10. 10 5. Electrical Stimulation  Allows researchers to determine the functions of distinct brain regions (i.e., functional localization).  Involves artificially stimulating distinct regions and assessing changes in behaviour.  Electrical stimulation is delivered through electrodes; the electrical current increases the firing of neurons at the tip of the electrode.

11. 11 The Motor Homunculus Primary motor cortex

12. 12  A recently developed form of stimulation is repeated trans-cranial magnetic stimulation. Magnetic pulses are applied to the scalp, creating an electrical current below the stimulation site. This method reduces the symptoms associated with depression, mania, obsessive-compulsive disorder, and post-traumatic stress disorder.

13. 13 6. Lesion  Allows researchers to determine the functions of distinct brain regions (i.e., functional localization).  Involves examining the consequences of naturally- occurring or deliberately produced injuries to neural tissue (i.e., lesions).

14. 14 Aspiration lesions Radio-frequency lesions Cryogenic blockade  A number of techniques exist to create deliberate lesions. Examples:

15. 15 A Lesion in Wernicke’s Area

16. 16 Example of the speech of an individual with Wernicke’s aphasia. The individual is describing a picture of a child taking a cookie. “Uh, well this is the... the … of this. This and this and this and this. These things going in there like that. This is … things here. This one here, these two things here. And the other one here, back in this one, this one look at this one.”

17. 17 What are the primary divisions of the nervous system? The nervous system is comprised of two major divisions: 1. Central Nervous System (CNS)  The CNS consists of two subdivisions: The brain and spinal cord.  The CNS is located in the skull and spine.

18. 18 The CNS Brain Spinal Cord

19. 19 2. Peripheral Nervous System (PNS)  The PNS is located outside of the skull and spine.  The PNS consists of nerves that extend throughout the body. These nerves: (a) carry sensory information about the external and internal environment to the CNS, and (b) carry motor signals from the CNS to other regions of the body.

20. 20 The PNS

21. 21 Research Methods and The Structure of the Nervous System 2. What are the primary divisions of the nervous system? 1.How do biological psychologists assess the structure and function of the nervous system? (continued)