Temporal patterns of sensory information are important cues in behaviors ranging from spatial analyses to communication. Neural representations of the temporal structure of sensory signals include fluctuations in the discharge rate of neurons over time (peripheral nervous system) and the differential level of activity in neurons tuned to particular temporal features (temporal filters in the central nervous system). This paper presents our current understanding of the mechanisms responsible for the transformations between these representations in electric fish of the genus Eigenmannia. The roles of passive and active membrane properties of neurons, and frequency-dependent gain-control mechanisms are discussed.

REFERENCES

Bastian
J.
(
1986
).
Gain control in the electrosensory system mediated by descending inputs to the electrosensory lateral line lobe
.
J. Neurosci
6
,
553
–.
Bastial
J.
(
1986
).
Gain control in the electrosensory system: a role for the descending projections to the electrosensory lateral line lobe
.
J. Comp. Physiol
158
,
505
–.
Bastian
J.
,
Yuthas
J.
(
1984
).
The jamming avoidance response of Eigenmannia: Properties of a diencephalic link between sensory processing and motor output
.
J. Comp. Physiol
154
,
895
–.
Berman
N. J.
,
Plant
J.
,
Turner
R. W.
,
Maler
L.
(
1997
).
Excitatory amino acid receptors at a feedback pathway in the electrosensory system: Implications for the searchlight hypothesis
.
J. Neurophysiol
78
,
1869
–.
Bialek
W.
,
Rieke
F.
,
De Ruyter van Steveninck
R. R.
,
Warland
D.
(
1991
).
Reading a neural code
.
Science
252
,
1854
–.
Bullock
T. H.
(
1982
).
Electroreception
.
Annu. Rev. Neurosci
5
,
121
–.
Bullock
T. H.
,
Hamstra
R. H.
,
Scheich
H.
(
1972
).
The jamming avoidance response of high-frequency electric fish, I and II
.
J. Comp. Physiol
77
,
1
–.
Carr
C. E.
,
Maler
L.
(
1985
).
A Golgi study of the cell types of the dorsal torus semicircularis of the electric fish Eigenmannia: Functional and morphological diversity in the midbrain
.
J. Comp. Neurol
235
,
207
–.
Carr
C. E.
,
Maler
L.
,
Heiligenberg
W.
,
Sas
E.
(
1981
).
Laminar organization of the afferent and efferent systems of the torus semicircularis of gymnotiform fish: Morphological substrates for parallel processing in the electrosensory system
.
J. Comp. Neurol
203
,
649
–.
Denk
W.
,
Sugimori
M.
,
Llinas
R.
(
1995
).
Two types of calcium response limited to single spines in cerebellar Purkinje cells
.
Proc. Natl. Acad. Sci. USA
92
,
8279
–.
Eilers
J.
,
Augustine
G. J.
,
Konnerth
A.
(
1995
).
Subthreshold synaptic Ca2+signalling in fine dendrites and spines of cerebellar Purkinje neurons
.
Nature
373
,
155
–.
Ferster
D.
,
Jagadeesh
B.
(
1992
).
EPSP—IPSP interactions in cat visual cortex studied with in vivo whole-cell patch recording
.
J. Neurosci
12
,
1262
–.
Fortune
E. S.
,
Rose
G. J.
(
1997
).
Passive and active membrane properties contribute to the temporal filtering properties of midbrain neurons in vivo
.
J. Neurosci
17
,
3815
–.
Fortune
E. S.
,
Rose
G. J.
(
1997
).
Temporal filtering properties of ampullary electrosensory neurons in the torus semicircularis of Eigenmannia: evolutionary and computational implications
.
Brain Behav. Evol
49
,
312
–.
Gabbiani
F.
,
Metzner
W.
,
Wessel
R.
,
Koch
C.
(
1996
).
FromG. J. ROSEANDE. S. FORTUNE1289 Temporal filters in the electrosensory system stimulus encoding to feature extraction in weakly electric fish
.
Nature
384
,
564
–.
Haag
J.
,
Borst
A.
(
1996
).
Amplification of high-frequency synaptic inputs by active dendritic membrane processes
.
Nature
379
,
639
–.
Hagedorn
M.
,
Heiligenberg
W.
(
1985
).
Court and spark: Electric signals in the courtship and mating of gymnotoid electric fish
.
Anim. Behav
33
,
254
–.
Harris
K. M.
,
Stevens
J. K.
(
1989
).
Dendritic spines of CA1 pyramidal cells in the rat hippocampus: serial electron microscopy with reference to their biophysical characteristics
.
J. Neurosci
9
,
2982
–.
Heiligenberg
W.
(
1973
).
Electrolocation of objects in the electric fish Eigenmannia (Rhamphichthyidae, Gymnotoidei)
.
J. Comp. Physiol
87
,
137
–.
Heiligenberg
W.
(
1989
).
Central processing of electrosensory information in gymnotiform fish
.
J. Exp. Biol
146
,
255
–.
Heiligenberg
W.
,
Baker
C.
,
Matsubara
J.
(
1978
).
The jamming avoidance response in Eigenmannia revisited: The structure of a neuronal democracy
.
J. Comp. Physiol
127
,
267
–.
Heiligenberg
W.
,
Dye
J. C.
(
1982
).
Labelling of electroreceptive afferents in gymnotoid fish by intracellular injection of HRP: The mystery of multiple maps
.
J. Comp. Physiol
148
,
287
–.
Jaffe
D. B.
,
Brown
T. H.
(
1997
).
Calcium dynamics in thorny excrescences of CA3 pyramidal neurons
.
J. Neurophysiol
78
,
10
–.
Maler
L.
,
Sas
E.
,
Carr
C. E.
,
Matsubara
J.
(
1982
).
Efferent projections of the posterior lateral line lobe in gymnotiform fish
.
J. Comp. Neurol
211
,
154
–.
Matsubara
J.
,
Heiligenberg
W.
(
1978
).
How well do electric fish electrolocate under jamming?
.
J. Comp. Physiol
149
,
339
–.
Metzner
W.
,
Heiligenberg
W.
(
1991
).
The coding of signals in the electric communication of the gymnotiform fish Eigenmannia: From electroreceptors to neurons in the torus semicircularis
.
J. Comp. Physiol
169
,
135
–.
Papa
M.
,
Segal
M.
(
1996
).
Morphological plasticity in dendritic spines of cultured hippocampal neurons
.
Neurosci
71
,
1005
–.
Partridge
B. L.
,
Heiligenberg
W.
,
Matsubara
J.
(
1981
).
The neural basis of a sensory filter in the jamming avoidance response: No grandmother cells in sight
.
J. Comp. Physiol
145
,
153
–.
Rocha
M.
,
Sur
M.
(
1995
).
Rapid acquisition of dendritic spines by visual thalamic neurons after blockade of N -methyl-D-aspartate receptors
.
Proc. Natl. Acad. Sci. USA
92
,
8026
–.
Rose
G.
(
1986
).
A temporal processing mechanism for all species?
.
Brain Behav. Evol
28
,
134
–.
Rose
G. J.
,
Call
S. J.
(
1992
).
Evidence for the role of dendritic spines in the temporal filtering properties of neurons: The decoding problem and beyond
.
Proc. Natl. Acad. Sci. USA
89
,
9662
–.
Rose
G. J.
,
Call
S. J.
(
1992
).
Differential distribution of ampullary and tuberous processing in the torus semicircularis of Eigenmannia
.
J. Comp. Physiol
170
,
253
–.
Rose
G. J.
,
Call
S. J.
(
1993
).
Temporal filtering properties of midbrain neurons in an electric fish: Implications for the function of dendritic spines
.
J. Neurosci
13
,
1178
–.
Rose
G. J.
,
Fortune
E. S.
(
1996
).
New techniques for making whole-cell recordings from CNS neurons in vivo
.
Neurosci. Res
26
,
89
–.
Shumway
C. A.
(
1989
).
Multiple electrosensory maps in the medulla of weakly electric gymnotiform fish. I. Physiological differences
.
J. Neurosci
9
,
4388
–.
Turner
R. W.
,
Maler
L.
,
Deerinck
T.
,
Levinson
R. S.
,
Ellisman
M. H.
(
1994
).
TTX-sensitive dendritic sodium channels underlie oscillatory discharge in a vertebrate sensory neuron
.
J. Neurosci
14
,
6453
–.
Turner
R. W.
,
Plant
J. R.
,
Maler
L.
(
1996
).
Oscillatory and burst discharge across electrosensory topographic maps
.
J. Neurophysiol
76
,
2364
–.
Watanabe
A.
,
Takeda
K.
(
1963
).
The change of discharge frequency by A.C. stimulus in a weakly electric fish
.
J. Exp. Biol
40
,
57
–.
Yuste
R.
,
Denk
W.
(
1995
).
Dendritic spines as basic functional units of neuronal integration
.
Nature
375
,
682
–.
This content is only available via PDF.