Fig. 2.
In vivo imaging of spontaneous AVA activity state transitions. (A) The command interneuron AVA is readily identifiable in the transgenic C. elegans strain QW1574 via selective expression of the calcium-sensitive green fluorescent protein GCaMP6s. (B) Calcium transients measured from the AVA neuron, captured as intensifications of cytoplasmic GCaMP fluorescence, are indicative of the neuron’s innate activity. (C, D) An increase in AVA fluorescence corresponds with a behavioral reversal event and is reflective of the activity state of the neuronal network mediating forward and backward movement as indicated. Individual calcium transient onset, “on” (C), and cessation, “off” (D), fluorescence traces of on and off transitions were overlaid and averaged (see Statistical Methods; shaded areas delineate the 95% CI). Hyperbolic tangent functions were fit to these respective on and off transitions and used to calculate the times at which the average traces reach the 5 and 95% fluorescent levels indicated by dashed lines (percentages are compared with the maximum value above baseline fluorescence, max(ΔF/F0)). (E, F) Hyperbolic tangent functions were also fitted to individual calcium transient onset and cessation fluorescence traces and used to calculate the average time required to shift from 5% of the maximum value above baseline fluorescence to 95% (rise time, E) and from 95 to 5% (fall time; F) respectively (solid error bars denote 95% CI, and dashed error bars show the SD). (G) The time derivatives of AVA activity state transitions were further calculated. Individual calcium transient onset and cessation fluorescence traces, acquired from worms during late adulthood, were differentiated, overlaid, and averaged (see Statistical Methods; shaded areas delineate the 95% CI; for onset transitions, isoflurane-exposed early and late adulthood n = 38 and 53 traces from 20 animals each, respectively, and control early and late adulthood n = 37 and 38 traces from 20 and 16 animals, respectively; for cessation transitions, isoflurane-exposed early and late adulthood n = 26 and 46 traces from 19 animals each, respectively, and control early and late adulthood n = 33 and 32 traces from 20 and 14 animals, respectively). *P < 0.05; **P < 0.01, unpaired two-tailed t test.

In vivo imaging of spontaneous AVA activity state transitions. (A) The command interneuron AVA is readily identifiable in the transgenic C. elegans strain QW1574 via selective expression of the calcium-sensitive green fluorescent protein GCaMP6s. (B) Calcium transients measured from the AVA neuron, captured as intensifications of cytoplasmic GCaMP fluorescence, are indicative of the neuron’s innate activity. (C, D) An increase in AVA fluorescence corresponds with a behavioral reversal event and is reflective of the activity state of the neuronal network mediating forward and backward movement as indicated. Individual calcium transient onset, “on” (C), and cessation, “off” (D), fluorescence traces of on and off transitions were overlaid and averaged (see Statistical Methods; shaded areas delineate the 95% CI). Hyperbolic tangent functions were fit to these respective on and off transitions and used to calculate the times at which the average traces reach the 5 and 95% fluorescent levels indicated by dashed lines (percentages are compared with the maximum value above baseline fluorescence, max(ΔF/F0)). (E, F) Hyperbolic tangent functions were also fitted to individual calcium transient onset and cessation fluorescence traces and used to calculate the average time required to shift from 5% of the maximum value above baseline fluorescence to 95% (rise time, E) and from 95 to 5% (fall time; F) respectively (solid error bars denote 95% CI, and dashed error bars show the SD). (G) The time derivatives of AVA activity state transitions were further calculated. Individual calcium transient onset and cessation fluorescence traces, acquired from worms during late adulthood, were differentiated, overlaid, and averaged (see Statistical Methods; shaded areas delineate the 95% CI; for onset transitions, isoflurane-exposed early and late adulthood n = 38 and 53 traces from 20 animals each, respectively, and control early and late adulthood n = 37 and 38 traces from 20 and 16 animals, respectively; for cessation transitions, isoflurane-exposed early and late adulthood n = 26 and 46 traces from 19 animals each, respectively, and control early and late adulthood n = 33 and 32 traces from 20 and 14 animals, respectively). *P < 0.05; **P < 0.01, unpaired two-tailed t test.

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