Fig. 5. Kinematics of the I2 muscle during biting versus swallowing. (A-D) Data from individual bites are shown to indicate the variability in individual responses. In all subsequent figures, only averaged data are shown. Data in A-D are plotted as length (mm) as a function of time (ms). (A) I2 kinematics in the first bite. This sequence from 7725 begins with frame 2 and ends with frame 25. The onset of the t₁ period (see Materials and methods) is frame 13. (B) I2 kinematics in the second bite. This sequence from 3213 begins with frame 26 and ends with frame 43. The onset of the t₁ period is frame 34. (C) I2 kinematics in the third bite. This sequence from 3213 begins with frame 43 and ends with frame 60. The onset of the t₁ period is frame 49. (D) I2 kinematics in the fourth bite. This sequence from 3222 begins with frame 53 and ends with frame 72. The onset of the t₁ period is frame 61. (E) Averaged data normalized to total cycle length. Lengths are not normalized. Values are means (solid lines) ± 1 s.d. (broken lines). Black lines, averaged data from biting responses; gray lines, averaged data from swallowing responses [data for swallowing in this and all subsequent figures are from Neustadter et al. (Neustadter et al., 2002a), re-analyzed using the new jaw line as described in Materials and methods]. Black vertical line represents the average t₄/t₁ border for the averaged bite data; gray vertical lines represent the average t₄/t₁ and t₁/t₂ borders for the averaged swallow data. (F) Schematic diagrams indicating the I2 length plotted in A for frames 1, 12, 19 and 24. Muscle I2 is highlighted with a black line.