Lateral Line Research: the Importance of Using Natural Stimuli
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placement and branching pattern, canal width, canal compartmentalization and the
number, size and placement of canal pores (e.g., Coombs et al. 1988).
3 Central Pathways
3.1 Ascending Pathways
Lateral line information reaches the brain via lateral line nerves. Upon entering the
brain, individual nerve fibers bifurcate into an ascending and a descending branch
which terminate throughout the entire medial octavolateralis nucleus (MON) (e.g.
Alexandre and Ghysen 1999). The terminal pattern implies that activity in any
afferent fiber reaches all the various parts of the medullary lateral line column.
Cells of the MON project bilaterally to a secondary brainstem nucleus, to the torus
semicircularis (lateral mesencephalic nucleus in elasmobranchs) and to the
contralateral MON (e.g. Boord and Montgomery 1989; McCormick and
Hernandez 1996). The torus semicircularis projects to the diencephalon which
relays information to the telencephalon (Wullimann 1998). In both cartilaginous
fishes (Bleckmann et al. 1989) and teleosts (Prechtl et al. 1998) there is a distinct
region in the pallium that responds to quasinatural water movement stimuli.
3.2 Descending Recurrent Pathways
The MON receives descending input from a secondary brainstem nucleus, which
receives input from the MON and the torus semicircularis (Montgomery et al.
1995). Discussed functions of descending recurrent inputs include gain control and
the establishment of central representations of expected sensory input (Montgomery eta!. 1995b).
Lateral line neuromasts receive efferent innervation from a rhombencephalic
(e.g., Song and Northcutt 1991) and, in some species, also from a diencephalic
nucleus (Roberts and Meredith 1989). In amphibians (Xenopus laevis) the activity
of efferent lateral line fibers is influenced by centers in or rostral to the diencephalon (Mtinz and Claas 1991 ). The efferent lateral line system can inhibit
and/or excite afferent activity (Roberts and Meredith 1989).
4 Physiology
4.1 Physiology of the Periphery
Since the work of Harris and van Bergeijk (1962), researchers have stimulated the
lateral line with constant volume vibrating spheres. To keep experimental
conditions defmed, fishes are fixed to a stationary holder. Recordings are not
151
placement and branching pattern, canal width, canal compartmentalization and the
number, size and placement of canal pores (e.g., Coombs et al. 1988).
3 Central Pathways
3.1 Ascending Pathways
Lateral line information reaches the brain via lateral line nerves. Upon entering the
brain, individual nerve fibers bifurcate into an ascending and a descending branch
which terminate throughout the entire medial octavolateralis nucleus (MON) (e.g.
Alexandre and Ghysen 1999). The terminal pattern implies that activity in any
afferent fiber reaches all the various parts of the medullary lateral line column.
Cells of the MON project bilaterally to a secondary brainstem nucleus, to the torus
semicircularis (lateral mesencephalic nucleus in elasmobranchs) and to the
contralateral MON (e.g. Boord and Montgomery 1989; McCormick and
Hernandez 1996). The torus semicircularis projects to the diencephalon which
relays information to the telencephalon (Wullimann 1998). In both cartilaginous
fishes (Bleckmann et al. 1989) and teleosts (Prechtl et al. 1998) there is a distinct
region in the pallium that responds to quasinatural water movement stimuli.
3.2 Descending Recurrent Pathways
The MON receives descending input from a secondary brainstem nucleus, which
receives input from the MON and the torus semicircularis (Montgomery et al.
1995). Discussed functions of descending recurrent inputs include gain control and
the establishment of central representations of expected sensory input (Montgomery eta!. 1995b).
Lateral line neuromasts receive efferent innervation from a rhombencephalic
(e.g., Song and Northcutt 1991) and, in some species, also from a diencephalic
nucleus (Roberts and Meredith 1989). In amphibians (Xenopus laevis) the activity
of efferent lateral line fibers is influenced by centers in or rostral to the diencephalon (Mtinz and Claas 1991 ). The efferent lateral line system can inhibit
and/or excite afferent activity (Roberts and Meredith 1989).
4 Physiology
4.1 Physiology of the Periphery
Since the work of Harris and van Bergeijk (1962), researchers have stimulated the
lateral line with constant volume vibrating spheres. To keep experimental
conditions defmed, fishes are fixed to a stationary holder. Recordings are not