Further Details of Putative Sharp Wave Ripple Recall Activity.

<p>(<b>a</b>) Statistics relating to dual coded recall following learning with the triplet-based BCM type STDP rule, when all background connections (i.e. between place cells and those encoding for all place fields that are not within three steps on the learned route) are set to <i>0</i> following learning. Data shown for <i>Φ</i> = <i>0.111</i> and averaged over <i>1000</i> randomly initialised recall epochs, illustrating the relative frequency of neurons that fired before (dark grey); at the same time as (medium grey); and after (light grey) the first action potential in any simulated neuron encoding for the next place field on the learned route. This can be directly compared with <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1000839#pcbi-1000839-g006" target="_blank">Figure 6f</a>. (<b>b</b>) Histogram of temporal magnitude for every erroneous spike fired during <i>1000</i> randomly initialised dual coded recall epochs with <i>Φ</i> = <i>0.111</i> following learning with the triplet-based BCM type STDP rule and theta modulated plasticity (that being the lowest recall fidelity displayed in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1000839#pcbi-1000839-g006" target="_blank">Figure 6f</a>). (<b>c</b>) The mean percentage of incorrectly timed recall spikes observed during sharp wave ripple recall activity, displayed in terms of the distance along the learned route, in place fields, from the externally stimulated place cells. Data is averaged over <i>1000</i> randomly initialised dual coded recall epochs for the BCM type STDP rules with <i>Φ</i> = <i>0.111</i>. (<b>d</b>) The effective speed of SWR activity – calculated using the time interval between the first spike caused by superthreshold external stimulation and the first subsequent spike in a place field encoding for the same place field following the propagation of activity along the entire length of the learned route – for different concentrations of ACh. Data is averaged over <i>1000</i> randomly initialised dual coded recall epochs, following learning with theta modulated plasticity.