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|Title:||Ultramorphological Study of Synaptic Activity and Efficacy Change in the Perifused Rat Hippocampal Slice|
|Author(s):||Chang, Fen-Lei Finland|
|Department / Program:||Psychology|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||This study examined anatomical correlates of synaptic activity produced efficacy change and high levels of continuous synaptic activation which did not produce efficacy change. Long term potentiation in hippocampal CA1 was used as a model of efficacy change. After potentiating stimulation (100Hz for 1 s or 200 Hz for 0.5 s), there were increases in numbers of shaft and nubbin synapses, suggesting an increase in the number of shaft synapses onto inhibitory interneurons and/or an enhancement of synapse formation through a transition of shaft, to nubbin, to full grown spine synapses. Postsynaptic spines also changed to a rounder shape, as indicated by decreases in spine perimeters, contact lengths, and % of 'cup' shaped spines.
No such changes occurred after continuous high level synaptic activation (40 Hz or 100Hz for 10 min), which produced no potentiation. In contrast, continuous high level electrical stimulation caused an increase in bouton mitochondrial area and a marginal increase in bouton area. The extent of persistence was also different between potentiation and activation effects. Potentiation-produced increases in numbers of shaft and nubbin synapses persisted over the 8 h test period, while the effect on spine shape disappeared after 2 h. Effects of continuous high level activation on mitochondrial and bouton areas were even more transient. These changes disappeared 2 h after stimulation. These results indicate that not only did continuous synaptic activation not produce physiologically recognizable potentiation, but that the anatomical effects were different and had a different level of persistence.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983.
|Date Available in IDEALS:||2014-12-15|