Table 2.

Passive and active membrane properties of juvenile and adult PV interneurons

JuvenileAdult
Firing pattern
    Delay first AP (ms)462 ± 57395 ± 79
    ISI average (ms)25.9 ± 1.224.2 ± 1.4
    Frequency adaptation1.03 ± 0.121.30 ± 0.09*
    Max ISI (ms)109 ± 23120 ± 40
    Min ISI (ms)20.3 ± 1.318.4 ± 1.3
    Max/Min ISI6.4 ± 1.77.6 ± 2.6
    CV frequency0.20 ± 0.020.20 ± 0.03
    F/I slope (Hz/pA)2.2 ± 0.31.2 ± 0.1***
Passive
    Vm (mV)−86 ± 1.4−87 ± 1.2
    Rm (MΩ)106 ± 10159 ± 12***
    Rheobase (pA)384 ± 46228 ± 16**
AP shape
    AP threshold (mV)−46.3 ± 1.5−49.6 ± 1.0*
    AP 10–90% rise (ms)0.27 ± 0.010.25 ± 0.01
    AP half-width (ms)0.54 ± 0.040.44 ± 0.03*
    AHP peak (mV)−24.7 ± 0.6−23.8 ± 1.0
    AHP latency (ms)2.2 ± 0.41.4 ± 0.2*
    AHP area (V/s)−298 ± 42−213 ± 15*
    Number of interneurons1420
  • Juvenile (P15–P17) or adult (P56–P65) PV interneurons are characterized by firing pattern, passive membrane properties, and AP shape (see Materials and Methods). Values shown as mean ± SEM. A t test was used to determine whether the value for juvenile was significantly different from that for adult (*p < 0.05, **p < 0.01, and ***p < 0.001). Note that the number of recorded interneurons is less than sampled for mRNA (19, juvenile; 21, adult) because not all interneurons sampled provided stable AP recordings.