Otherwise, the rate of the cell is the difference between excitation buy OSI-906 and inhibition: λiv(r)=(Iiv(r)−0.9⋅maxjDG(Ijv(r)))⋅H(Iiv(r)−0.9⋅maxjDG(Ijv(r)))where
H is the Heaviside function. Figure S1 gives an insight into how granule cell rate maps are obtained from grid cells and LEC cells and how rate is influenced by both the entorhinal input of the cell and the population inhibition. The convergence of the EC input onto granule cells was estimated by the number of synapses as ∼1200 for grid cells (de Almeida et al., 2009a), and following the same procedure, as ∼1500 for LEC inputs (see Supplemental Experimental Procedures). Synaptic weight (W) is defined by the synaptic size (s) ( de Almeida et al., 2009a): W(s)=s0.2(ss+0.0314). The synaptic size distribution was defined by the measured size distribution of excitatory synapses onto granules cells (Trommald and Hulleberg, 1997): P(s)=100.7(1−e−(s0.022))⋅(e−(s0.018)+0.02⋅e−(s0.15))with s ranging from 0 to 0.2. Cells with an average firing rate above 10% of the mean average firing rate of the cell population were PFI-2 purchase considered active. Composite PV correlation has been used in the analysis of experimental data to observe the reduction of rate coincidence at the same position in the DG when the shape of the
arena is morphed (Leutgeb et al., 2007). PVs are obtained by storing in a vector the rate at a certain position bin of each cell of a population. The correlation between the PV of the same group on two different conditions gives a measure of how the condition
affects the overall population activity. The PV correlation value is the mean correlation value considering all bins. The number of place fields was estimated from the rate map for active cells in each stage Adenosine of the morphing. Rate maps were smoothed by a Gaussian kernel with a nine-pixel radius. Pixels with a firing rate above 20% of the peak rate were considered active. Groups of contiguous active pixels (>200 and <2500 pixels) with an average rate exceeding the mean population firing rate and with peak activity above two times the mean population firing rate were considered to be a firing field. Persistent place fields were obtained by applying place field analysis on the average rate map for all morphing shapes (Leutgeb et al., 2007). Three different curves were fit to the in-field rate for each persistent place field following the morphing: (1) linear regression, (2) quadratic regression, and (3) sigmoid function. Fits with p < 0.05 were considered significant, and each place field was assigned to the category with the highest explained variance (F values). The level of the rate remapping effect is measured for each persistent place field (p) whose average mean rate for the two extreme shapes of the morphing (λSR) is above 10% of the mean average firing rate of the cell population.