Screenshot of the web-based questionnaire showing a single experimental trial using the AS.

<p>The picture (in this example just a placeholder and not part of the IAPS collection) is randomly displayed either on the left or on the right side of the screen. Similarly, the order of the pleasure and arousal dimensions is randomized.</p

Scatterplots representing the linear correlation between AS and SAM pleasure (r_s = .852) and arousal (r_s = .860).

<p>The red line indicates the best fit.</p

The EC/DG/CA3 model.

<p>(<b>A</b>) In our model of the EC/DG/CA3 system, the excitatory granule cells of DG receive convergent input from EC (2700∶1) combined with a delayed feedback inhibition (delay: 3.3±0.4 msec) imposed by local interneurons. Excitatory cells in CA3 receive convergent input from both EC (2900∶1) and DG (∼50∶1) together with delayed feedback inhibition from local interneurons (delay: 3.3±0.4 msec) and recurrent excitatory input (delay: 1 msec). (<b>B</b>) Delayed feedback inhibition mediates internal competition that selects which cell fires in a given gamma cycle. Trace of three sample cells with different strength of excitatory feedforward currents. Time is represented at the horizontal axis. Gray area designates the window between the first spike and the onset of global inhibition. Cell voltage and input currents are shown on the ordinate. (<b>C</b>) Rate maps of sample EC neurons shown for both extreme shapes. (<b>D</b>) Action potentials (red dots) with overlaid trajectory (gray line) and equivalent rate maps of sample DG and CA3 cells.</p

Effect of grid cell realignment on the CA3 population response to morphing.

<p>Reproduction of the results of Colgin et al. <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003641#pcbi.1003641-Colgin1" target="_blank">[21]</a> (left box) is compared to our experimental results (right box). In the condition in which the animals are trained in the same arena at the same location (red line), morphing induces a graded decrease in population correlation if compared to the initial state (red solid line) and a graded increase in correlation if compared to the final state (red dotted line). Under this condition, grid cells do not realign <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003641#pcbi.1003641-Leutgeb2" target="_blank">[19]</a>, <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003641#pcbi.1003641-Fyhn1" target="_blank">[40]</a>. In the condition in which the animals are trained in different arenas or in the same arena but at different locations (black line), morphing induces a sharp and deep decrease in correlation if compared to the initial state (black solid line) and a graded increase in correlation if compared to the final state (black dotted line). Under this condition, grid cells realign <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003641#pcbi.1003641-Fyhn1" target="_blank">[40]</a>.</p

Recurrent collaterals explain the differences in the response of DG and CA3 to morphing observed experimentally [19].

<p>(<b>A</b>) Progressive change in the PV correlation of DG (dashed blue line) and CA3 (dashed orange line). (<b>B</b>) Average rate overlap and (<b>C</b>) mean spatial correlation of individual cells rate maps as a function of morphing as observed experimentally (top) and its equivalent analysis of simulated data with best model fit (bottom), including the response of CA3 without recurrent collaterals (light gray line). (<b>D</b>) PV autocorrelation for large distances (50 cm) measured experimentally (left) and with model best fit (right). (<b>E</b>) Mean number of place fields measured experimentally (left) and with model best fit (right).</p

The number of intermediate sessions affects the quality of pattern reconstruction.

<p>(<b>A</b>) PV correlation between smallest morph (1-2) and two successive recordings of the first environment (1-1′) as a function of the learning rate. For 1-2, there is no intermediate session, whereas for the 1-1′, there are five intermediate sessions (2–5). With a learning rate of about .03, the measured PV correlation is the same for 1-1′ and 1-2 within one full session. (<b>B</b>) Rate maps of the simulated activity of a sample CA3 cell during regular and inverse morphing showing hysteresis.</p