LTP(Long-term potentiation)

LTP(Long-term potentiation): 長期增益

"The enduring facilitation of synaptic transmission that occurs following the activation of a synapse by high-frequency stimulation of the presynaptic neuron."

(Pinel, J. (1993). Biopsychology,(2nd Edition) p.515　Allyn & Bacon: Toronto)

Originally, this phenomenon was discovered in the Aplysia. However, more recently LTP has been found to occur in mammalian nervous system as well. This was an extremely important finding because it suggested that LTP could be the cellular basis of neural implementation for learning and memory.

Long-term potentiation has been found to occur in the mammalian hippocampus. This is an important finding because the hippocampus is believed to be one of the major brain regions responsible for processing memories.

LTP is one of the first examples of mechanisms of neural implementation of a cognitive function. This is one of the major goals of cognitive science, and hence is a very important discovery.

目前對LTP研究最多，也瞭解最多的相關突觸，位於海馬迴(hippocampus)。

海馬迴與許多種類之短期記憶有關。在此區的突觸，若突觸前神經在200毫秒內產生100次以上的刺激，可造成突觸後神經去極化的敏感度增加，也就是使興奮性突觸後電位(excitatory post-synaptic potential, EPSP)的強度比平時還大，且此現象可持續數小時至數天，甚至數個月，這個效應即為長期增益效應.

此外，LTP指的是突觸前刺激會引發較強的興奮性突觸後電位，而不是活動電位,

換句話說，LTP是指突觸前的刺激，可引發更強之突觸後電位的效應，在此情形下，可使神經更易達閾值而引發活動電位。