Table 1.
Details on the stimuli used in Gervain et al. (2008) experiment 1 and in the current experiment.
Fig 1.
The block design used in the current study.
Condition order was randomized and counter-balanced across infants. Letters from A to L represent the 12 syllables extracted from the CV inventory.
Fig 2.
(A) Configuration of probe sets overlaid on an infant skull, superimposed on a schematic infant brain for illustrative purposes and should not be interpreted as a precise mapping of probe channels to ROIs. (B) Picture of a newborn participant with optodes placed upon the head.
Fig 3.
The concentration changes of oxy- and deoxyHb were averaged across the 12 blocks for each condition and for each channel. Numbers and location of channels correspond to the placement shown in Fig 2A. The x-axis represents time in seconds; the y-axis shows concentration in mmol x mm. The rectangle along the x-axis indicates time of stimulation. The continuous red and blue lines in the graphs represent oxyHb and deoxyHb concentrations, respectively, in response to the ABC grammar. The dashed magenta and cyan lines represent oxyHb and deoxyHb concentrations, respectively, in response to the ABB grammar. Note that the time line on the x-axis is of adequate duration given that it corresponds to the following sequence of events: 5s time-window preceding the onset of the block, block presentation (9.9s or 10.9s), and the following long inter-block silences (20 s or 25 s), thus a total duration ranging from 34.9s and 40.9s. This total period was divided in 7 time windows of equal length (~5.7s), and only the signal obtained between the time-windows 2 and 6 was used for statistical analyses, i.e. approximately between 5.7s and ~28.6s after block onset.
Fig 4.
Schematic infant brain and bar graphs of oxyHb and deoxyHb concentrations (in mM.mm) for channels yielding significant t-test comparing responses to: ABB+ABC vs. baseline, (B) ABB vs. baseline, (C) ABC vs. baseline, (D) ABB vs. ABC.
Significance levels for t-tests are indicated for each channel by p-values: ‘+’ marginally significant without correction for multiple comparisons;’**’ p < .01 significant without correction; ‘*’ p < .05 significant without correction; ‘FDR’ p < .05 significant after correction for multiple comparisons using the False Discovery Rate (FDR) [52], calculated using the FDR online calculator (http://sdmproject.com/utilities/?show=FDR). The FDR method is typically recommended to correct for multiple comparisons, such as multiple t-test analysis. Given a set of p-values, the FDR method returns p-values adjusted, controlling for the false discovery rate, i.e. the expected proportion of false discoveries amongst the rejected hypotheses.
Fig 5.
The time course of the responses for the two grammars in the left fronto-temporal ROI (channels 1, 3, 8) vs. the right fronto-temporal ROI (channels 14, 17, 22).
The y-axis shows the average oxyHb concentration in mmol x mm. ABC is plotted in light-grey; ABB in black. (A) Linear regression lines of the oxyHb concentrations fitted on the data points provided by the 12 consecutive blocks for the two grammars, plotted on the x-axis. (B) The bars indicate the average oxyHb concentration for the first (“initial blocks”) and the last three blocks (“final blocks”).