Neuroscience 9-4-07,9-6-07 - Neuroscience Biology and Behavior Biologic al Psychology The branch of psychology concerned with the links between biology

9/04/07 Neuroscience: Biology and Behavior Biologic al Psychology The branch of psychology concerned with the links between biology, behavior, and the environment. Sub-Fields of Biological Psychology • Behavioral Neuroscience • Neuropsychology • Behavior Genetics • Physiological Psychology • Biopsychology Neurons and Behavior • Our nervous system is made up of billons of neurons • Specialized cells that create a communication system throughout the body Parts of Neurons • Dendrite The bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body. • Axon The extension of a neuron, ending in branching terminal fibers, through which messages are sent to other neurons or to muscles or glands. • Myelin Sheath A layer of fatty cells segmentally encasing the fibers of many neurons, Enables vastly greater transmission speed of neutral impulses Action Potential • A neural impulse; a brief electrical charge that travels down an axon • Generated by the movement of positively charged atoms in and out of channels in the axon’s membrane Threshold • The level of stimulation required to trigger a neural impulse All of nothing response • Neurons either fire or don’t • When they fire, they do so with full force • If the stimulation doesn’t reach threshold, they don’t fire • This is called “All or nothing” response Speed of Neural Transmission

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9/04/07 • How fast does an action potential travel? Synapse • Junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron • Tiny gap at this junction is called the synaptic gap or cleft Vesicles, Neurotransmitters, Receptors • Vesicles: Tiny containers of neurotransmitters at the end of a neuron • Neurotransmitters: