SynapseSynapse- Nerve impulses are transmitted through a functional gap or intercellular spacebetween neurons called the synapse or the synaptic gap. Although nerve impulses areconducted electrically within the neuron, in the synapse they are continued through aspecial group of chemicals called neurotransmitters.See also Synapse on GaleSpatial Summation- Stimulus 1 produces a depolarization (EPSP) and stimulus 2 producesa hyperpolarization (IPSP). The summated change in membrane potential at the axonhillock does not exceed threshold, therefore an action potential does not occur.Temporal Summation- results when two action potentials arrive in very close successionat a single presynaptic terminal. The first action potential causes a local depolarization inthe postsynaptic membrane that remains for a few milliseconds before it disappears,although its magnitude decreases through time. Before the local depolarization caused bythe first action potential repolarizes to its resting value, a second action potentialinitiates a second local depolarization. Temporal summation results when the second localdepolarization summates with the remainder of the first local depolarization. If the
summated local depolarization reaches threshold at the axon hillock, an action potential isproduced in the postsynaptic neuron. 5Neurotransmitter- Neurotransmitters are chemical agents secreted at the end of axonsof nerve cells that diffuse across the synaptic gap and transmit information to adjoiningcells such as neurons, muscle cells, and glands by altering their electrical state or activity.There are many neurotransmitters with a variety of structures and functions; two of theprinciple ones are acetylcholine and norepinephrine.See also Neurotransmitters or Neuroplasticity 5 Citations 1. Fitzke, Frederick W., et al. "Spatial summation for single line and multi-line motion stimuli." Perimetry Update 2002/2003. Kugler Publications, 2002. 335+. Academic OneFile. Web. 11 Oct. 2012. 2. "Neurotransmitter." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. 4th ed. Detroit: Gale, 2008. Student Resources in Context. Web. 11 Oct. 2012.
3. "Synapse." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. 4th ed.Detroit: Gale, 2008. Student Resources in Context. Web. 15 Oct. 2012.4. Curatolo, . Assessment of regional analgesia in clinical practice and research; Electrophysiologicalmethods. 2000. Photograph. British Medical BulletinWeb. 11 Oct 2012.<http://bmb.oxfordjournals.org/content/71/1/61.full>.5.The Whacky, Wild and Misleading World Of Neurotransmitter Testing. 2009. Photograph. Primal BodyPrimal MindWeb. 11 Oct 2012. <http://www.primalbody-primalmind.com/?p=366>.