Biomedical Engineering Reference
In-Depth Information
short duration pulses the second upward deflection was a reliable marker to
indicate that a spike had been elicited.
Longer duration pulses elicited longer latency spiking that occurred after
completion of the stimulus pulse spikes (Figure 19.2a, left, asterisks). These
Figure 19.2. Early and late phases of spiking are activated by different mechanisms. (a) Left
trace: A second phase of spiking (individual late-phase spikes indicated by asterisks) is
elicited after completion of long duration pulses (vertical arrow indicates completion of pulse
in a-c). Spikes are eliminated in TTX (right trace). Stimulus pulse waveform and timing
is represented at top. (b) Late phase spiking in a different cell (left trace) is completely
eliminated by 1mM CNQX, 10mM AP7 and 5mM Curare (right trace). Inset: expanded
time scale of the interval between the dotted lines from control (dotted) and excitatory
synaptic blocker (solid) traces. The normalized TTX response from a different cell is shown
for comparison. The early phase spike remains intact. (c) Late phase spiking initiated by
long pulses (left, asterisks) is eliminated by reducing the duration of the pulse to 0.1ms
(right trace). The scale bar in (c) applies to all traces. Cathodic and anodic pulses were
3ms for long pulses (a-c) and 0.1ms for short pulse (c). Interval was 5ms for all pulses.
Search WWH ::
Custom Search