QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online February 1, 2008
Journal of Experimental Biology 211, 587-598 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.012096

This Article Summary Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Flammang, B. E. Articles by Lauder, G. V. Search for Related Content PubMed PubMed Citation Articles by Flammang, B. E. Articles by Lauder, G. V.

Speed-dependent intrinsic caudal fin muscle recruitment during steady swimming in bluegill sunfish, Lepomis macrochirus

Brooke E. Flammang^* and George V. Lauder

Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA

View larger version (55K): [in this window] [in a new window]   Fig. 1. Anatomy of intrinsic caudal muscles, overlaid on a computer microtomography (µCT) scan of a bluegill sunfish tail. Arrows in the bottom diagram indicate the direction of movement of fin components caused by muscle contraction as determined from electrical stimulation experiments. FD, flexor dorsalis; FV flexor ventralis; HL, hypochordal longitudinalis; IC, infracarinalis; IR, interradialis, designated by fin ray position; SC, supracarinalis. The fin rays are numbered dorsal to ventral. Not depicted in this diagram are the lateralis superficialis (LS) and lateral muscle band of the axial myomeres, which lie superficially to the intrinsic caudal muscles pictured above.

View larger version (81K): [in this window] [in a new window]   Fig. 2. (A) Electromyographic sequence (amplified 5000x) of a bluegill sunfish (Lepomis macrochirus) swimming while the speed of the flow tank was gradually increased from swim speeds of 0 to 2.0 L s–1. Muscle activity is shown for the supracarinalis (SC), hypochordal longitudinalis (HL), flexor dorsalis (FD), interradialis (IR) designated by the number of its dorsally corresponding fin ray, and flexor ventralis (FV) on the left side, and the infracarinalis (IC) and red myomere (RED) on the right side of the fish. (B,C) Enlarged subset of sequences of fish swimming at 1.0 (B) and 2.0 (C) L s–1. The scale for sequences B and C is in the lower right corner below C. EMG color corresponds to the anatomical diagram in Fig. 1.

View larger version (40K): [in this window] [in a new window]   Fig. 3. Posterior view of fish (images above plot), mean lateral excursion of tail fin (A), mean tail fin height (B), and activity of intrinsic caudal muscles (C) throughout one tail beat during steady swimming at 0.5 L s–1 (N=7 tail beats). Lateral excursion and tail height are plotted as mean (circles) ± s.e.m. Colored horizontal bars denote muscle activity within 75% confidence interval (CI) and error bars denote the 95% CI. Parentheses around muscle names indicate muscles inactive at this swimming speed. Muscle activity is shown for the left (L) and right (R) sides; supracarinalis (SC), hypochordal longitudinalis (HL), flexor dorsalis (FD), interradialis (IR) designated by the number of the dorsally corresponding fin ray, flexor ventralis (FV), infracarinalis (IC), lateralis superficialis (LS), and red myomere on the right side of the caudal peduncle. Dotted vertical lines indicate the times of each image at the top. Bar color corresponds to the anatomical diagram in Fig. 1.

View larger version (44K): [in this window] [in a new window]   Fig. 4. Posterior view of fish (images above plot), mean lateral excursion of tail fin (A), mean tail fin height (B), and activity of intrinsic caudal muscles (C) throughout one tail beat during steady swimming at 1.2 L s–1 (N=14). Lateral excursion and tail height are plotted as mean (circles) ± s.e.m. Colored horizontal bars denote muscle activity within 75% confidence interval (CI) and error bars denote the 95% CI. Muscle activity is shown for the left (L) and right (R) sides; supracarinalis (SC), hypochordal longitudinalis (HL), flexor dorsalis (FD), interradialis (IR) designated by the number of the dorsally corresponding fin ray, flexor ventralis (FV), infracarinalis (IC), lateralis superficialis (LS), and red myomere on the right side of the caudal peduncle. Dotted vertical lines indicate the times of each image at the top. Bar color corresponds to the anatomical diagram in Fig. 1.

View larger version (44K): [in this window] [in a new window]   Fig. 5. Posterior view of fish (image above plot), mean lateral excursion of tail fin (A), mean tail fin height (B), and activity of intrinsic caudal muscles (C) throughout one tail beat during steady swimming at 2.0 L s–1 (N=12). Lateral excursion and tail height are plotted as mean (circles) ± s.e.m. Colored horizontal bars denote muscle activity within 75% confidence interval (CI) and error bars denote the 95%CI. Muscle activity is shown for the left (L) and right (R) sides; supracarinalis (SC), hypochordal longitudinalis (HL), flexor dorsalis (FD), interradialis (IR) designated by the number of the dorsally corresponding fin ray, flexor ventralis (FV), infracarinalis (IC), lateralis superficialis (LS), and red myomere on the right side of the caudal peduncle. Dotted vertical lines indicate the times of each image at the top. Bar color corresponds to the anatomical diagram in Fig. 1.

View larger version (39K): [in this window] [in a new window]   Fig. 6. Histograms of muscle activity duration (A), onset of muscle activity relative to lateral red muscle onset (B), and EMG burst intensity (C) of intrinsic caudal muscles on the right side at 0.5 (black bars), 1.2 (red bars), and 2.0 L s–1 (green bars). Error bars indicate standard error of the mean. Muscle activity is shown for the red myomere (RED), hypochordal longitudinalis (HL), flexor dorsalis (FD), flexor ventralis (FV), supracarinalis (SC), infracarinalis (IC), interradialis (IR) designated by the number of the dorsally corresponding fin ray, and lateralis superficialis (LS). Some muscles were not active at 0.5 L s–1 (e.g. FV) and therefore a gap is present instead of a black bar.

View larger version (20K): [in this window] [in a new window]   Fig. 7. Principal component analysis of muscle activity duration, relative onset of muscle activity and EMG burst intensity for fish swimming at 1.2 L s–1 (red triangles) and 2.0 L s–1 (green circles). Each point represents one measurement of muscle activity over one tail beat cycle. A description of the variable types loading heavily on each factor is given below the axis label. Further explanation of factor loadings is given in the text.