Table 2. Details of juxtacellular labeling.

Number of juxtacellular labeling attempts on the final recording day for each animal (neurobiotin is metabolized within 24 hr). Letters refer to individually recorded neurons. E.g. in animal TV58, recorded neurons ‘e’ and ‘g’ were selected for juxtacellular labeling; in animal TV50 only neuron ‘a’ was recorded and labeled. A ‘labeling attempt’ refers to the application of current pulses to a recorded neuron. Modulation refers to successful entrainment of action potentials to the duration of positive current pulses (Pinault, 1996). Strength and duration of modulation are also estimated in order to predict the labeling strength (Table 1).

Animal name	Labeling attempts from single neurons	Modulated neurons	Recovered neurons
TV58	2 (e, g)	1 (g, very strong, >5 min; rostral of e)	1 (g)
TV50	1 (a)	1 (a, strong, 77 s)	1 (a, damaged)
MS14	1 (i)	1 (i, strong, 1 min)	One strong (i); one weak, dorsal of i, dendrites cross with i, potentially gap-junction coupled
MS19	1 (b)	1 (b, strong, 30 s)	1 (b)
AJ50	4 (g-j)	3 (g, strong, 6 s, lost; h strong 30 s, dorsal of g; j, strong, 2 min, rostral of h)	Two strong (h, j); one very weak; dorsal of h, potentially gap-junction coupled
AJ44	1 (j)	1 (j, strong, 12 s)	1 (j)
MS74	1 (b)	1 (b, strong, 2 min)	1 (b, damaged)
MS17	1 (k)	1 (k, strong, 30 s, lost cell after)	1 (k)