TABLE 2.Two types of ventral tegmental area (VTA) principal neurons
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Cell Capacitance, pF | Input Resistance, MΩ | Action potential (AP) |
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Amplitude, mV | Half-Width, ms | Threshold, mV | Peak AHP, mV | AHP Decay Slope, mV/s | |||||||
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Irregular-type neurons | 29.4 ± 2.1 (15) | 896 ± 49 (19) | 63.6 ± 1.2 (43) | 3.8 ± 0.1 (43) | –41.2 ± 0.7 (43) | –60.1 ± 0.7 (43) | 110.6 ± 11.0 (43) | ||||
Tonic-type neurons | 24.2 ± 2.0 (20) | 1097 ± 162 (14) | 66.0 ± 1.7 (40) | 3.3 ± 0.1 (40) | –40.5 ± 0.5 (40) | –67.9 ± 0.9 (40) | 110.2 ± 8.8 (40) | ||||
P > 0.08 | P > 0.2 | P > 0.2 | P < 0.0001 | P > 0.4 | P < 0.001 | P > 0.9 |
All average values are expressed as means ± SE. Statistical comparison was done by Student’s t-test to assess significant differences. Cell capacitance was determined after the capacitative transients were cancelled.
Membrane input resistance was determined by hyperpolarizing current pulses that induced a voltage shift of 10–15 mV negative
to the resting potential, where the voltage-sag was not detected. AP half-width was measured half way between AP threshold
and AP peak. AHP slope was measured by fitting a line from the AHP peak to the rising phase toward a subsequent AP spike.
Numbers of neurons in parentheses.