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Schaffer collaterals are axon collaterals given off by CA3 pyramidal cells in the hippocampus. These collaterals project to area CA1 of the hippocampus〔Vago DR, Kesner RP(2008). Disruption of the direct perforant path input to the CA1 subregion of the dorsal hippocampus interferes with spatial working memory and novelty detection. Behav. Brain Res. 189(2): 273–83〕 and are an integral part of memory formation and the emotional network of the Papez circuit, and of the hippocampal trisynaptic loop. It is one of the most studied synapses in the world and named after the Hungarian anatomist-neurologist Károly Schaffer. As a part of the hippocampal structures, Schaffer collaterals develop the limbic system, which plays a critical role in the aspects of learning and memory. The signals of information from the contralateral CA3 region leave via the Schaffer collateral pathways for the CA1 pyramidal neurons. Mature synapses contain fewer Schaffer collateral branches than those synapses that are not fully developed.〔Schiess AR, Scullin C & Partridge LD (2010). Maturation of Schaffer collateral synapses generates a phenotype of unreliable basal evoked release and very reliable facilitated release. ''European Journal of Neuroscience''. 31:1377-1387.〕 Many scientists try to use the Schaffer collateral synapse as a sample synapse, a typical excitatory glutamatergic synapse in the cortex that has very well been studied in order to try to identify the rules of both the patterns of stimulation in electrical rules and the chemical mechanisms by which synapses get persistently stronger and which synapses get persistently weaker as well and to develop medication and treatment to cure the chronic diseases, such as dementia and Alzheimer's disease. Moreover, they believe that studying the Schaffer collateral can provide a whole range of understanding how Schaffer collaterals allow us to intervene with drug-treatments and with electrical-stimulation so that the quality of human experience can be improved. ==Development== "Schaffer collateral is the conductor of the orchestra, but not the actual instrument that plays the music" - An individual needs the functional hippocampus to store long-term memories as synaptic plasticity in terms of storing information. Once those memories are stored, they remain stored in very long time. However, they slowly fade away, which means that there are some roles for the hippocampus when talking to the neocortex in order to prevent diminishing those memories away. It is clear that whatever plastic changes occurring in the hippocampus involve in directing the process by which memories get stored.Dr. Patrick K. Stanton (). The Schaffer collateral is involved in activity-dependent plasticity and the information processes that always are processed through the hippocampus all the time. The Schaffer collateral clearly affects whether the target cells fire action potentials or not. However, at the same time, it is triggering the process that takes much longer whereby some synapses get stronger and some get weaker, and overall the patterns of synaptic strength of the network all evolve over time. Moreover, Schaffer collateral axons develop excitatory synapses that are scattered over the dendritic arborization〔()〕 of hippocampal CA1 pyramidal neurons.〔Smith MA, Ellis-Davies GC & Magee JC (2003). Mechanism of the distance-dependent scaling of Schaffer collateral synapses in rat CA1 pyramidal neurons. ''Journal of Physiology''. 548.1:245-258〕 In the early stage of long-term potentiation, Schaffer collaterals release glutamate that binds to AMPA receptors of CA1-dendrites. The process of developing a network of CA3-to-CA1 recurrent excitatory glutamatergic synapses alters the frequency of spontaneous action potentials in Schaffer collaterals. By adulthood, CA3 recurrent network activity is reduced, the frequency of spontaneous action potentials is decreased in Schaffer collaterals, and a single release locus synapse with one dendritic spine on a given CA1 pyramidal neuron can be developed by Schaffer collateral axons.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Schaffer collateral」の詳細全文を読む スポンサード リンク
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