The idea that synaptic modifications in the brain underlie learning and memory was first hypothesized by Donald Hebb in his pivotal work The Organization of Behaviour: A Neuropsychological Theory (Hebb, 1949). Since then, the theory has gained strong support from various lines of research where the discovery of synaptic long-term potentiation (LTP) and long-term depression (LTD) within the mammalian hippocampus present the strongest line of evidence (Howland and Wang, 2008). These phenomena have since received a lot of attention and they currently constitute the two major cellular models for investigating synaptic plasticity (Howland and Wang, 2008). In particular, LTP has been under special interest as a putative model for the molecular and
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There are many characteristics of LTP that contribute to its desirability as a model for investigating memory processes. For instance, apart from the functional definition of LTP as a long-lasting increase in synaptic strength following tetanic stimulation, LTP is also rapidly induced, persistent and correlates with natural brain rhythms, all of which contributes with circumstantial support for the connection between LTP and memory storage (Shores and Matzel, 1997). Moreover, a majority of studies have used high-frequency stimulation (HFS) to induce LTP in the CA1 area of the hippocampus and thus yielded considerable knowledge …show more content…
The use of IA training served to overcome the issues with iterative learning tasks and detection of synaptic changes as it creates a rapid and stable memory trace which is linked to genetic changes in the CA1 region of the hippocampus (Whitlock et al., 2006). Moreover, the authors also used specific biomarkers that could separate LTP and LTD taking place at different synapses, thereby overcoming the problem with bidirectional modifications cancelling each other (Whitlock et al., 2006). Furthermore, to conclude that IA training actually induced a change by a common mechanism, the authors tested whether it would full fill the criteria for mimicry and occlusion. Using various techniques, the authors were able to illustrate that IA training did mimic the effects of HFS. For instance, they were able to demonstrate that IA training caused a NMDA receptor-dependent increase in phosphorylation of the LTP biomarker serine 831 in the GluR1 subunit of the AMPA receptor, whereas phosphorylation at the LTD biomarker serine 845 in the GluR1 subunit was unaffected. Secondly, they were able to show that both GluR1 and GluR2 where translocated to the biochemical fraction of the synaptoneurosome whereas NR1 was not. And finally, they found that the slope of the evoked field excitatory
There are many characteristics of LTP that contribute to its desirability as a model for investigating memory processes. For instance, apart from the functional definition of LTP as a long-lasting increase in synaptic strength following tetanic stimulation, LTP is also rapidly induced, persistent and correlates with natural brain rhythms, all of which contributes with circumstantial support for the connection between LTP and memory storage (Shores and Matzel, 1997). Moreover, a majority of studies have used high-frequency stimulation (HFS) to induce LTP in the CA1 area of the hippocampus and thus yielded considerable knowledge …show more content…
The use of IA training served to overcome the issues with iterative learning tasks and detection of synaptic changes as it creates a rapid and stable memory trace which is linked to genetic changes in the CA1 region of the hippocampus (Whitlock et al., 2006). Moreover, the authors also used specific biomarkers that could separate LTP and LTD taking place at different synapses, thereby overcoming the problem with bidirectional modifications cancelling each other (Whitlock et al., 2006). Furthermore, to conclude that IA training actually induced a change by a common mechanism, the authors tested whether it would full fill the criteria for mimicry and occlusion. Using various techniques, the authors were able to illustrate that IA training did mimic the effects of HFS. For instance, they were able to demonstrate that IA training caused a NMDA receptor-dependent increase in phosphorylation of the LTP biomarker serine 831 in the GluR1 subunit of the AMPA receptor, whereas phosphorylation at the LTD biomarker serine 845 in the GluR1 subunit was unaffected. Secondly, they were able to show that both GluR1 and GluR2 where translocated to the biochemical fraction of the synaptoneurosome whereas NR1 was not. And finally, they found that the slope of the evoked field excitatory