Journal of Neuroscience, Vol 5, 2269-2280, Copyright © 1985 by Society for Neuroscience
Structure and function of electrosensory neurons in the torus semicircularis of Eigenmannia: morphological correlates of phase and amplitude sensitivity
G Rose and W Heiligenberg
Structure-function relations in the electrosensory system of Eigenmannia
were examined by labeling physiologically characterized neurons of the
dorsal torus semicircularis. The sensitivity of cells to modulations in
amplitude (AMs) and modulations in differential phase was determined.
Approximately half of the 48 cell types defined by Golgi studies (Carr,
C.E., and L. Maler (1985) J. Comp. Neurol. 235: 207-240) were identified in
this manner. The majority of the neurons located in laminae (8a, b, c, and
d, and 9 exhibited sensitivity to differential phase. In laminae 5 and 7,
however, in addition to neurons which were sensitive to differential phase,
many cells were found that were purely AM sensitive. Differential phase
sensitivity originates in the small cells of lamina 6 (Heiligenberg, W.,
and G. Rose (1985) J. Neurosci. 5: 515-531), the exclusive termination site
of phase-coding afferents from the electrosensory lateral line lobe. Cells
that had dendritic extensions into the neuropil of lamina 6 exhibited
sensitivity to differential phase, whereas neurons lacking dendrites in
this lamina were only excited by AMs. These findings support the notion of
a relationship between the morphology and laminar position of a neuron and
its function.