Basic response characteristics of BLA neurons as determined from spike density functions
| Measure | Mean | SD | Range |
|---|---|---|---|
| Spontaneous firing rate, Hz | 3.7 | 3.3 | 0.15–19.9 |
| Shortest excitatory response onset latency, ms | 41.8 | 40.7 | 7.4–180.8 |
| Average latency to peak firing rate, ms | 81.9 | 42.3 | 18.8–224.4 |
| Normalized best peak firing rate (SD > spontaneous firing) | 20.76 | 19.5 | 3.9–113.7 |
| Avg. magnitude of increase in mean spike rate, Hz | 6.2 | 5.4 | 1.7–45.5 |
| Avg. magnitude of decrease in mean spike rate, Hz | 4.0 | 1.6 | 2.2–8.3 |
| Excitatory phase response duration, ms | 11.4 | 6.9 | 1–31.7 |
| Inhibitory phase response duration, ms | 94.0 | 40.3 | 37–250 |
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Means, SD, and ranges for call-response measurements made from basolateral amygdala (BLA) neurons. Response latencies, magnitudes, and durations were averaged across significant call responses for a given neuron before averaging each measure across neurons, thus giving each neuron an equal weighting despite differences in the number of call responses across neurons. Excitatory and inhibitory response magnitudes and durations were calculated separately. Excitatory durations reflect the longest continuous interval that the spike density function exceeded 2 SD above the spontaneous spike density. Inhibitory durations were calculated in a similar manner (see MATERIALS AND METHODS for details). Response magnitudes are expressed as the change in the mean spike rate over the whole 250-ms interval following stimulus onset and are reported for units with evoked mean firing rates greater than (n = 69) or less than (n = 16) spontaneous (P < 0.01, Wilcoxon rank sum text).