The retention of cell assemblies with Hebbian and symmetric STDP windows.

2014-07-09T03:05:13Z (GMT) by Naoki Hiratani Tomoki Fukai
<p>(<b>A</b>) An asymmetric STDP window was calculated for <i>J<sub>ij</sub><sup>EE</sup></i> = 0.15. (<b>B</b>) The retention time significantly varies with the release probability of STD. We defined the retention time as a period with a sufficiently large relative weights: <i>w<sub>p</sub></i>>0.1<i>J<sub>EE</sub></i>. (<b>C</b>) Raster plot of spiking activity is shown for the Hebbian STDP rule shown in <b>A</b>. (<b>D</b>) A symmetric STDP window was calculated for <i>J<sub>ij</sub><sup>EE</sup></i> = 0.15. (<b>E</b>) Dynamics of the average synaptic weights at <i>u<sub>sd</sub></i> = 0.2 within (blue) and between (black) assemblies. (<b>F</b>) Raster plot of spiking activity for the symmetric STDP rule shown in <b>D</b>. (<b>G</b>) Relationship between the release probability <i>u<sub>sd</sub></i> and relative weight <i>w<sub>p</sub></i> at <i>t</i> = 30 min. (<b>H</b>) (top) We constructed a histogram of the number of activation over all cell assemblies shown in <b>F</b>. The abscissa shows the number of activation of each assembly normalized by the average number of activation of all assemblies. (middle) We calculated a histogram for the occurrence of all possible 20 (5×4) sequential transitions between two assemblies. The occurrence number of each transition was normalized by the average occurrence number over all transitions. (bottom) Histograms of triplet transitions, such as assembly 1 → 2 → 1 (left) and 1 → 2 → 3 (right), are shown after a normalization by all possible 80 (5×4+5×4×3) triplet transition patterns. All three histograms are obtained from the results of five simulation trials.</p>