1. Biology and Neurology UNIT ON THE BRAIN

2. What is Neurology and introducing The Neuron

3. What do we mean by biology?  Physiological Psychology is the study of behavior as influenced by biology. It draws its techniques and research methods from biology and medicine (particularly neurology) to examine psychological phenomena.

4. What is Neurology?  Neurology is the branch of medicine or biology that deals with the anatomy, functions, and organic disorders of nerves and the nervous system.

5. Physiological Techniques  Many different techniques are used to examine the interrelationship between the brain and behavior.  Examples include EEG, CAT scans, MRI, and PET.

6. Scan Types CAT ScansMRIsEEGsPET Scans computerized axial tomography magnetic resonance imaging electroencephalogrampositron emission tomography Also known as a CT scan, it uses x-ray technology to take multiple cross- sectional views of the inside of the body. Compared to regular x- rays, a CT scan can take clearer images of organs, bone, soft tissue, blood vessels, and other areas of the body. This is particularly useful when examining parts of the brain. A noninvasive medical diagnostic technique that uses a large magnet and radio waves. Health care professionals use MRI scans to diagnose a variety of conditions, from torn ligaments to tumors. MRIs are very useful for examining the brain and spinal cord. During the scan, you lie on a table that slides inside a tunnel-shaped machine. The scan can take a long time, and you must stay still during it. An electroencephalogram (EEG) is a test to measure the electrical activity of the brain. So, in essence, EEG is used to look at your brain activity. It can help diagnose seizures. It may also be used to diagnose or monitor many neurological-health conditions. An EEG may be done to show that the brain has no activity, in the case of someone who is in a deep coma. It can be helpful when trying to decide if someone is brain dead. A nuclear medical imaging technique that produces a three- dimensional image or picture of functional processes in the body. A PET scan uses a small amount of radioactive material (tracer). More radioactive material accumulates in areas that have higher levels of chemical activity. This often corresponds to areas of disease and shows up as brighter spots on the PET scan.

7. Brain Reading?

8. The Nervous System  The Nervous system can be divided into two distinct subsystems:  The Central Nervous System (or CNS) – The brain and the spinal cord  The Peripheral Nervous System (or PNS) – All other nerves in the body

9. The Brain and CNS  Located in the skull and is the central processing center for thought, motivations, and emotions. The brain is made up of neurons, or nerve cells.  Neurons form a network that extends to the spinal cord, which is encased in the protective bones of the spin (known as the vertebrae). The nerves of the spine are responsible for conveying information to and from the brain and the PNS.  Both the brain and the spine are bathed in a protective liquid called cerebrospinal fluid.

10. The Neuron

11.  Dendrite: a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body.  Cell Body: the bulbous, metabolic center of a neuron, containing the cell nucleus, also known as a Soma.  Nucleus: Spherical DNA-containing structure of the cell body  Axon: the long, narrow process that projects from the cell body. The conical area of a neuron cell body, where the axon begins and the nerve impulse is generated, is known as the Axon Hillcock.  Nodes of Ranvier: Gaps in the myelin sheath of the axons of peripheral neruons. Action potentials can 'hump' from node to node, thus increasing the speed of conduction (saltatory conduction).  Axon terminal buttons: buttonlike endings of the axon branches, which release chemicals into the synapses  Mylein sheath: a fatty substance that helps insulate neurons and speeds the transmission of nerve impulses.

12. Synaptic Gap  The axon terminal buttons come very close to the dendrites of other neurons, but they do not touch. The gap between them is known as a synapse.  The buttons release neurotransmitters across the synaptic gap.  Neurotransmitters serve as a type of “chemical messenger.”  The Neurotransmitters bind with receptors on subsequent dendrites.

13. Neural Communication  Neural communication occurs both within and between cells. Communication within cells is electrochemical.  Electrochemical - chemical reactions brought about by electricity  For such communication to occur, a cell must reach a certain level of stimulation known as the threshold of excitation. Once this threshold is surpassed, an action potential forms.  The action potential is also referred to as a nerve impulse.

14. Neural Communication  When an action potential occurs, the neuron “fires”, causing the permeability of the cell membrane to change, which permits electrically charged ions of potassium and sodium to enter the cell.  This event repeats down the axon, which allows the action potential to travel down to the axon terminal buttons. The action potential causes the buttons to release the neurotransmitters.  Action potentials are “all or none”, meaning that they are either generated or not, with nothing in between. They are also always of a fixed strength; never weaker or stronger.

15. Neural Communication  After a neuron fires, it passes through an absolute refractory phase, during which no amount of stimulation can cause it to fire again.  The absolute refractory phase is followed by the relative refractory phase, in which the neuron needs much more stimulation than usual to fire again.