Fig. 1

Group-averaged waveforms for typically developing (TD) and CLN3 disease groups over frontal scalp sites (composite average of F3, Fz and F4). Auditory event-related potentials (ERPs) to standard tones (blue trace) and deviant tones (red trace) are presented with standard error of the mean indicated by gray shading. Stimulus onset was at 0ms, indicated by the vertical dotted line. Panel A shows responses for the fastest stimulation rate (450ms stimulus onset asynchrony (SOA)). Plotted in the panel below the ERPs (yellow trace) is the subtraction waveform (deviant minus standard), isolating the MMN-related activity. TD controls are shown to the left of each panel and CLN3 disease individuals to the right. Panel B shows the responses for the medium paced rate (900ms SOA), and panel C shows responses for the slowest rate (1800ms SOA). A clear MMN (difference between standard and deviant traces) was evident at all SOAs for the TD control group. However, a clear MMN was present only for the 450ms and 900ms SOAs in the CLN3 disease group. The time period of interest is depicted by light blue shaded panels representing the defined time where we obtain average MMN amplitudes for every individual and across each SOA