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. 2021 May 18;10:e60090. doi: 10.7554/eLife.60090

Figure 2. Surface area and % signal change of area 3b topographic maps do not differ significantly between younger and older adults.

(A) Significant topographic finger maps of younger and older adults averaged separately over the group of younger adults and over the group of older adults. Data are visualized on average surfaces of the current set of subjects (younger/older).White dotted lines show the schematic outline of area 3b. (B) Map dispersion d and Fourier transformed (FT, gray arrow indicates stimulation order) data of significant topographic group maps of younger and older adults (d young: 0.68 ± 0.002, d old: 0.72 ± 0.002). Lower d indicates less stable topographic arrangements over the group. Black dotted lines indicate the area of the significant topographic map. (C) Significant topographic FT maps of each single participant (P1-P36). See Figure 2—figure supplement 1 and Figure 2—figure supplement 3 for zoomed-in views of individual maps. (D,H) Response amplitudes (in %) of topographic maps (D) and of individual fingers (H) in area 3b compared between younger and older adults (mean ± SE and individual data). (E,I) f-values of topographic maps (E) and of individual fingers (I) in area 3b compared between younger and older adults (mean ± SE and individual data). (F,G,J) Surface area of topographic maps of area 3b of younger and older adults; values extracted from original (F) and resampled (G) surfaces of the topographic maps, and of individual fingers (J) (mean ± SE and individual data). Shown are data of n = 19 younger adults and n = 17 older adults. See Figure 2—figure supplement 3 for significant differences in response amplitudes between younger and older adults during fixed amplitude stimulation.

Figure 2.

Figure 2—figure supplement 1. Zoomed-in topographic maps of younger adults.

Figure 2—figure supplement 1.

Significant topographic FT maps of each single younger participant (P1–P19).
Figure 2—figure supplement 2. Zoomed-in topographic maps of older adults.

Figure 2—figure supplement 2.

Significant topographic FT maps of each single older participant (P20–P36).
Figure 2—figure supplement 3. Tactile detection thresholds and response amplitudes during fixed amplitude stimulation in younger and older adults.

Figure 2—figure supplement 3.

(A) Detection thresholds (mean ± SE and individual data) for younger and older adults, separately for each digit (D1–D5). The initially obtained stimulus intensities for each digit, representing the tactile detection thresholds, were logarithmically transformed (log100.1mg) before proceeding with further analysis. For the ANOVA with the factors digit and age on tactile detection thresholds, we obtained a main effect of digit (F(4,192)=9.81, p<0.001), a main effect of age (F(1,38)=48.56, p<0.001), and an interaction between age and digit (F(4,192)=5.16, p<0.01). Post hoc tests revealed that the main effect of digit was due to higher detection threshold for D1 compared to D4 (t(88.82) = 2.58, p<0.05), for D1 compared to D5 (t(91.97) = 2.49, p<0.05), for D2 compared to D4 (t(98)=2.42, p<0.05), and for D2 compared to D5 (t(98)=2.33, p<0.05). The main effect of age was due to significantly higher detection thresholds for older compared to younger adults (younger: mean = 0.80 ± 0.04, older: mean = 1.37 ± 0.07, t(35.83) = 6.97, p<0.001). (B) Response amplitudes of the area 3b finger map in response to maximal (and identical) amplitude stimulation to all fingers of the right hand at once. Older adults showed significantly higher response amplitudes compared to younger adults (younger: 1.05 ± 0.01, older: 1.08 ± 0.008, t(34)=-2.10, p<0.05). (C) Correlations between detection thresholds (see A) and response amplitudes (see B) within the groups of younger and older adults were not significant (i.e. p>0.15).