Table 1.
Summary of data used in analysis
| Animal ID | Electrode Type | Recording # | Electrode # | Electrode Placement |
Recording Duration, min |
# Breath Cycles |
# Single Units Extracted |
Mean Single-Unit Spike Rate, Hz | Within-Burst Single-Unit Spike Rate, Hz |
|---|---|---|---|---|---|---|---|---|---|
| Bird 1 (F-BF) | CNTF | 1 | 1 | R. VS | 191 | 29,255 | 1 | 8.83 | 27.80 |
| CNTF | 1 | 2 | L. VS | 137* | 21,540 | 1 | 10.29 | 39.63 | |
| CNTF | 1 | 3 | L. sVTB | 191 | 29,311 | 0 | |||
| Bird 2 (F-BF) | CNTF | 1 | 1 | L. VS | 8 | 861 | 1 | 8.98 | 60.44 |
| CNTF | 2 | 2 | L. VS | 70* | 9,372 | 0 | |||
| CNTF | 2 | 3 | L. VS | 109 | 14,290 | 0 | |||
| Bird 3 (F-BF) | CNTF | 1 | 1 | R. Exp | 29 | 3,467 | 0 | ||
| CNTF | 1 | 2 | R. Exp | 29 | 2,551 | 1 | 2.83 | 93.49 | |
| CNTF | 1 | 3 | R. Exp | 29 | 2,585 | 1 | 4.75 | 111.56 | |
| Bird 4 (F-BF) | CNTF | 1 | 1 | R. Exp | 151 | 14,543 | 1 | 8.48 | 46.30 |
| CNTF | 1 | 2 | R. Exp | 151 | 14,557 | 0 | |||
| Bird 5 (F-BF) | CNTF | 1 | 1 | L. Exp | 249 | 16,300 | 1 | 10.43 | 81.02 |
| CNTF | 1 | 2 | L. Exp | 249 | 17,360 | 1 | 31.51 | 75.90 | |
| CNTF | 1 | 3 | L. Exp | 181* | 11,677 | 1 | 5.42 | 32.93 | |
| Bird 6 (F-ZF) | CNTF | 1 | 1 | L. sVTB | 11 | 1,560 | 1 | 13.46 | 75.03 |
| CNTF | 1 | 2 | L. sVTB | 11 | 1,509 | 0 | |||
| CNTF | 2 | 1 | L. sVTB | 3 | 328 | 1 | 15.76 | 106.08 | |
| CNTF | 2 | 2 | L. sVTB | 3 | 353 | 0 | |||
| CNTF | 2 | 3 | L. VS | 3 | 354 | 0 | |||
| CNTF | 3 | 1 | R. sVTB | 4 | 398 | 0 | |||
| Bird 7 (F-ZF) | CNTF | 1 | 1 | L. VS | 12 | 1,231 | 1 | 15.76 | 142.15 |
| CNTF | 2 | 2 | L. VS | 10 | 718 | 0 | |||
| Bird 8 (M-ZF) | CNTF | 1 | 1 | L. VS | 13 | 1,184 | 0 | ||
| CNTF | 1 | 2 | L. sVTB | 13 | 1,192 | 0 | |||
| Bird 9 (M-ZF) | SSW | 1 | 1 | sVTB | 6 | 749 | 0 | ||
| Bird 10 (M-ZF) | SSW | 1 | 1 | L. sVTB | 3 | 435 | 0 | ||
| Bird 11 (M-ZF) | SSW | 1 | 1 | VS | 3 | 334 | 0 | ||
| SSW | 2 | 1 | sVTB | 5 | 252 | 0 | |||
| Bird 12 (M-ZF) | SSW | 1 | 1 | sVTB | 3 | N/A | 0 | ||
| Bird 13 (M-ZF) | SSW | 1 | 1 | L. sVTB | 5 | N/A | 0 | ||
| SSW | 1 | 3 | L. VS | 5 | N/A | 0 | |||
| SSW | 2 | 2 | L. sVTB | 4 | N/A | 0 | |||
| Bird 14 (M-ZF) | SSW | 1 | 1 | L. sVTB | 5 | N/A | 0 | ||
| SSW | 1 | 2 | L. VS | 5 | N/A | 0 | |||
| SSW | 1 | 3 | R. VS | 5 | N/A | 0 |
As described in methods, we quantified whether each recording from both CNTF and SSW electrodes included one or more isolatable single motor unit (“# single units extracted”). In cases where we were able to isolate a single motor unit, we quantified both the single unit’s mean firing rate over time (mean rate across bursting and silent periods) as well as its mean firing rate within each burst (mean rate within bursts, excluding interspike intervals that separate spikes from consecutive respiratory bursts). Note that because different motor units fire different number of spikes per burst, a unit with a low mean firing rate can have a high within-burst firing rate (if the average burst contains few spikes but those spikes occur with very short interspike intervals) and vice versa. As described in the text, all CNTF and SSW electrodes were placed on the muscle surface. BF, Bengalese finch; CNTF, carbon nanotube fiber bipolar electrodes; Exp, expiratory muscle group; F, female; L, left; M, male; R, right; SSW, stainless steel fine-wire bipolar electrodes; sVTB, superficial ventral tracheobronchial; VS, ventral syringeal; ZF, zebra finch. *Recordings that were terminated due to signal loss. All other recordings were terminated by experimenter when the signal SNR was still robust because sufficient data had been collected.