Figure 3. Ontogenic evolution of motoneuronal membrane properties from stages E13.5 to P0.

A, comparison of motoneuronal response to depolarizing pulses, at E13.5, E16.5 and P0, showing that spike thresholds are similar at all stages of development whereas the resting membrane potential (V_rest) is 20 mV lower at E16.5 and P0 compared to E13.5. B, corrected spike threshold evolution throughout embryonic development. C, evolution of V_rest (corrected values) from E13.5 to P0. At each stage of development, circles represent individual measurement whereas black squares indicate mean values (±s.e.m.). D, evolution of motoneuronal R_in. The horizontal grey bar indicates the limits of the mature input resistance (between maximal and minimal s.e.m. values), between E16.5 and P0. E, maturation of motoneuronal membrane capacitance between E13.5 and P0. Values are given in Table 1.