unit 1 biological bases of behavior : neurotransmittions

neurotransmittion

the process by which neurons communicate with each other through electrical and chemical signals.

threshold

level of stimulation required to trigger an action potential in a neuron. It is the minimum amount of stimulation necessary to produce a response.

Action Potential

brief electrical impulse that travels along the axon of a neuron — occurs when the neuron receives a stimulus that causes the inside of the cell to become more positively charged than the outside

All-O-Nothing Prinicpal

states that once a neuron reaches its threshold of excitation, it will fire an action potential at full strength.

• if stimulus is strong enough to trigger an action potential, the neuron will respond with a full-strength impulse.

• the stimulus is below the threshold, the neuron will not fire an action potential at all.

Depolarization

phase of action potential where the inside of the neuron becomes less negative compared to the outside due to the influx of positively charged ions, such as sodium ions, through ion channels in the cell membrane.

Refractory Period 

brief period following an action potential during which a neuron is unable to generate another action potential — this period occurs because the neuron's sodium channels are temporarily inactivated and the cell membrane returns to its resting state.

Resting Potential

 stable, negative electrical charge that exists across the cell membrane of a neuron when it is not actively transmitting signals — maintained by the unequal distribution of ions, with more sodium ions outside the cell and more potassium ions inside.

Reuptake

process in which neurotransmitters that have been released into the synapse are reabsorbed by the presynaptic neuron from which they were originally released.

Multiple Scleosis “MS”

chronic autoimmune disease that affects the central nervous system, including the brain and spinal cord.