 |
Click on arrows numbered one through seven to see how lateral line
stimulation patterns (left panel) change as the fish approaches the
source. Static patterns on the left are modeled for each position at a
single instant in time for maximum accelerations of the sphere in one
direction only.  |
| Stimulation patterns along lateral line canals of the mottled sculpin corresponding to one of 7 positions on the right. Each colored circle represents the stimulation level at a single canal neuromast, modeled from the pressure difference between the two surrounding pores. Pressure differences for each inter-pore spacing have been converted into units of acceleration so that stimulation levels can be expressed in decibels (dB) re: threshold levels of excitation (0.001 m/sec2), as measured empirically from posterior lateral line nerve fibers of the mottled sculpin. Colors at the red end of the spectrum represent positive pressure differences (flow acceleration in one direction inside the canal), whereas those on the blue end represent negative pressure differences (flow acceleration in the opposite direction).hereas those on the blue end represent negative pressure differences (flow acceleration in the opposite direction). Note that as the fish approaches, an image of the source is formed as a central 'hot' (red) spot, often surrounded by contrasting blues and that this image becomes more narrowly focused as the fish gets closer. | Actual approach pathway (from video) followed by a mottled sculpin towards a 50 Hz vibrating sphere. Each numbered arrow represents the position of the fish's head at each step in the pathway, starting with position 1 at the time of stimulus onset and culminating in position 7, when the fish strikes at the sphere. Double arrow head centered on the sphere depicts the axis of vibration and dashed blue lines show the flow pattern about the sphere. |