Fig. 2
Recording sites, neuronal firing and spike sorting quality metrics. Location of the microelectrodes at the tip of the depth electrodes in Montreal Neurological Institute’s MNI152 space projected on the (a) parasagittal plane (x = −25.2 mm), (b), coronal plane (y = −7.0 mm), (c) transverse plane (z = −12.4 mm) and color coded (cyan, hippocampus; magenta, entorhinal cortex; yellow, amygdala). (d) Example neuron. Top: (Peristimulus time histogram, bin size, 500 ms, step size, 20 ms). Shaded areas represent ± s.e.m. across trials of all spikes associated with the neuron. Inset: mean extracellular waveform ± s.e.m. Middle: periods of significance (black) between low-workload trials (set size 4, 45 trials) and high-workload trials (set sizes 6 and 8, 46 trials, P < 0.05, cluster based non-parametric permutation test). Bottom: raster plot of trials reordered to set size and RT for plotting purposes only. Compared to set size 4 (blue), the neuron fires more for set size 6 (green) and set size 8 (red). (e) Histogram of percentage of inter-spike intervals (ISI) < 3 ms. The majority of neurons had less than 0.5% of short ISI. (f) Histogram of average firing rate for all neurons. (g) Histogram of the signal-to-noise ratio (SNR) of the peak of the mean waveform.
