Neuron “Talk” “What one neuron tells another neuron is simply how much it is excited.” (Francis Crik, 1994) “All information processing in the brain involves neurons ‘talking to’ each other at synapses” (Snyder, 1984)

Neural Communication Biological Psychology branch of psychology concerned with the links between biology and behavior some biological psychologists call themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists Neuron a nerve cell the basic building block of the nervous system

Neural Communication Action Potential / Impulse 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 (to get it excited). Excitation – the process of making the neuron receiving NT more likely to generate an action potential. Inhibition - the process of making the neuron receiving NT less likely to generate an action potential.

Neural Communication Dendrite Axon Myelin [MY-uh-lin] Sheath 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 [MY-uh-lin] Sheath a layer of fatty cells segmentally encasing the fibers of many neurons enables vastly greater transmission speed of neutral impulses

Neural Communication

Tips to Remember Ions have a charge either (+) or (-), when they move it makes ELECTRICITY = Action Potential All matter has a natural tendency to move from a crowded to a less crowed situation. (-) ions trapped inside! A neuron’s membrane is normally impermeable, but NT weaken it , allowing the “pump” to begin.

Neural Communication/Transmission depolarization – change in the cell’s membrane potential. all-or-none principle - the cell either fires completely or not at all; it doesn’t fire a little or a lot. direction of impulse - the cells only fire one way, the impulse can’t come the other direction. refractory period - after a cell fires, it won’t fire again for a certain period of time. resting potential (or polarization)- the cell is “waiting” to fire. The overall negative charge inside the neuron waiting for depolarization the flood of positive ions (Na) to enter.

Neural Transmission With a neighbor/partner… Discuss how neural transmission is like flushing a toilet. Include these elements in your discussion: Depolarization Polarization All-or-none principle Direction of impulse Refractory period Threshold Resting potential Action potential

Toilet & Neural Transmission depolarization - represented by the toilet flushing all-or-none principle - the toilet either flushes completely or not at all; it doesn’t flush a little or a lot direction of impulse - the toilet only flushes one way, the impulse can’t come the other direction (you hope!) refractory period - after you flush the toilet, it won’t flush again for a certain period of time, even if you push the handle repeatedly threshold - you can push the handle a little bit, but it won’t flush until you push the   handle past a certain critical point - this corresponds to the level of excitatory neurotransmitters that a neuron must absorb before it will fire resting potential- if you are using a toilet with a tank, the water in the tank can represent resting potential. The toilet is “waiting” to fire, and the water in the tank represents the overall negative charge inside the neuron waiting for depolarization action potential - the action potential is represented by opening the flap in the tank and the water

Neural Communication Synapse Neurotransmitters 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 Neurotransmitters chemical messengers that traverse the synaptic gaps between neurons when released by the sending neuron, neuro-transmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether it will generate a neural impulse

Neural Communication Dopamine Pathways Serotonin Pathways