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Home , Eigenmannia, Eigenmannia virescens, Electric fish

9/28/2011

e-organ October 3

Please email Wikipedia Project title to Carl Hopkins by Monday AM e- e-receptor L20. The Jamming Avoidance Response (J.A.R.) of (1: Behavior) September 28, 2011 Carl D. Hopkins

Outline “Passive” is electrical listening

1) Electroreception and electrogenesis. – Electroreception arose as a 6th sense in aquatic vertebrates as a means for detecting bioelectric current arising from muscles and epithelial tissues of prey. – Several of generate weak electric discharges from e-organs; the e-organs are used for communication or object detection. – Powerful electric discharges evolved later for or defense. 2) Independently, 2 large clades of e-fish evolved elaborate e- communication. – Some species have pulse discharges others have wave discharges. 3) Wave fish jam each other when the discharges have the same ? frequency. – Can’t e-locate when jammed. 4) The jamming avoidance response (JAR) shifts the discharge frequency away from the jamming frequency – JAR restores electrolocation 5) The JAR is an ideal sensory/motor system for tracing out the entire neural circuit for a complex behavior.

Kalmijn, A. (1971) J. Exp. Biol. (see Hopkins, 2010)

Electroreception is present in many aquatic vertebrates Electroreception arose early in vertebrates and was lost and re-grained. Electric organs: a model system for study of parallel of novelty

electroreception

5 © Hopkins. In Lavoué et al, in preparation

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** Lavoué, Sébastien, Miya, Masaki, Arnegard, M. E. , Sullivan, J. P., Hopkins, C. D. and Nishida, M. (in Electric Fishes preparation). Simultaneous origins of electrogenesis in fishes. Electric organs arose Two independent lineages independently in 6 lineages of of fishes speciated fishes. rapidly at about the same time (after independent evolution of electroreception). Elasmobranchs Torpedo rays Horizontal timescale is in million years before present Skates (Raja) (Mya). Horizontal bars at nodes are 95% age (ray-finned fishes) credibility intervals. – Mormyroids • (1 family, 1 species) Last temporal stages of the separation of Africa and • (1 family, 200+ species) are – Siluriformes: indicated with three • Malapteruridae (1 family, 3-10 species ?) inserts. – (7 families, 150+ species) – : Uranoscopidae (stargazers)

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Mormyriformes Gymnotiformes 2 FAMILIES 198 SPECIES 18 GENERA

ISICHTHYS C.D. Hopkins

Adontosternarchus sachsi

HIPPOPOTAMYRUS

C.D. Hopkins

BOULENGEROMYRUS Sternarchorhynchus roseni C.D. Hopkins

CAMPYLOMORMYRUS C.D. Hopkins

Sternopygus macrurus BRIENOMYRUS PETROCEPHALUS virescens C.D. Hopkins C.D.9 Hopkins 10C.D. Hopkins

Electric fish produce either “pulse” discharges or “Active” Electrolocation “wave” discharges

Resistive object (glass rod).

Discovered using glass rod inside clay pot training paradigm (Lissmann, 1958).

recorder (detects hit)

** Lavoué, Sébastien, Miya, Masaki, Arnegard, M. E. , Sullivan, J. P., Hopkins, C. D. and Nishida, M. (in preparation). Simultaneous origins 12 of electrogenesis in teleost fishes.

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EIGENMANNIA VIRESCENS ELECTRIC COMMUNICATION

300 Hz

10 ms

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Swinging fish quantifies electrolocation F=400; S = F+/- 40 Hz performance Ft= fish frequency (400 Hz); S= external sine wave stimulus

rods Electrolocation GAIN fish gain = out/in

S-F

PHASE swinging rods Rods swing, fish follows Rods swing, fish bumps - plastic rod inside rod diameter = 15.6 mm into them. i o electrically-‘transparent’ diameter = 3.7 mm agar

Heiligenberg, 1974 Conclusion: Eigenmannia is unable to electrolocate when external stimulus is 15 similar in frequency to its own discharge.16

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THE JAR = jamming avoidance response Jamming Avoidance Response

Watanabe A and Takeda K (1963) The change of discharge frequency by A.C. stimulus in a weakly electric fish. J Exp Biol 40:57-66.

Theodore H. Bullock and H. Scheich

Walter Heiligenberg

Eigenmannia

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Frequency Clamp

330

315

Stimulus frequency ‘tracks’ the fish’s EOD frequency. Moves up or down until asymptote (takes 20 seconds). Switch stimulus from +deltaF to –deltaF.

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Key Stimuli “Key” Stimuli for JAR 1. |S-F| < 4 Hz. Q? What are the essential conditions needed to evoke a JAR? 2. Two signals: S (stimulus) + F(fish).

or S S1 (artificial EOD + S2 (artificial jamming stimulus) F F F is silenced with + S Fish’s pacemaker is monitored in tail. S1 (F substitute) delivered between gut and tail.

EOD Frequency EOD F = fish frequency, S = stimulus S2 delivered through external electrodes

? ? 3. Geometry for two signals. PM PM S S2 Condition Response S1 (substitute EOD) Silence F. Stimulus = S1 + S2 (same geometry) no JAR JAR Stimulus= S + S (differential geometry) JAR JAR 1 2

S1 (tail only) + S2 (head only) JAR Thus: NO apparent connection between pacemaker and sensory areas. (No corollary discharge)

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The Stimulus What is the stimulus?

400 sine wave 1 both fish generate EODs sine wave 2 FIsh 1, senses self plus fish 2 404

400 + amplitude envelope 404 is identical for +df strong S1 and -df moderate S2

Interval between zero beat crossings

Strong S1 phase of S1+S2 zero S2 relative to S1 alone very small beat

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What is the nature of the real stimulus? Mixing of Two Signals

The mixing of two signals is modulated both in amplitude and in phase.

Summed signals

phase, plotted against amplitude.

advance delay 27 28

What differs between + F and - F? JAR Video

400 +402 demo

400 +398 demo

Heiligenberg’s algorithm: advance delay advance delay Determine the sign of rotation of circle

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Clever Experiment Shows Need for both phase and amplitude information Electroreceptors

AMPULLARY TUBEROUS compartment A gets both phase and amplitude modulated signal, B gets pure sine wave

A gets amplitude modulated, B gets phase modulated.

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Ampullary Electroreceptors Code for D.C. Peripheral Receptors stimuli.

Tonic activity in absence of stimulus T-unit: fires on zero-crossing (every cycle) of stim. Increase firing rate on D.C. +ve outside. P-unit: probability codes amplitude of stimulus; Decrease firing rate on D.C. –ve outside. P(spike) ~ amplitude of stimulus. ‘Frequency code’

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Neuronal responses are close match to Neuroanatomy of JAR phase/amplitude plots

Overview of entire pathway.

Torus semicircularis

Electrosensory Lobe (ELL)

3 ‘redundant’ maps of skin

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Lessons from JAR References

1. Electric fish use EOD for electrolocation of objects: active location of Watanabe, A., Takeda, K. (1963) The change of discharge objects. frequency by A.C. stimulus in a weak electric fish. J. Exp. Biol. 2. Eigenmannia (a wave species) is jammed by sinusoidal stimuli near their own frequency (electrolocation performance deteriorates when ΔF < 4 40: 57-66. Hz). Bullock, T.H., Hamstra Jr., R., Scheich, H. (1972) The jamming 3. Eigenmannia performs JAR to avoid jamming. Both F and F . JAR is a avoidance response of high frequency electric fish. J. comp. model for understanding decision making. 4. JAR depends on two inputs, S1 + S2 (no reference to pacemaker) Physiol. 77: 1-22. 5. JAR depends on differential geometry. Heiligenberg, W. (1991). Neural nets in electric fish. Cambridge, 6. Two cues: amplitude modulation + phase modulation Massachusetts: MIT Press. 7. counter clockwise rotation if +ΔF, clockwise rotation if -ΔF 8. Two sensory cues: AM, PM 9. Two receptor types: amplitude coder (P), phase coder (T)

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Pulse Discharges Wave Discharges Electroreception

pulse discharge

1 s 1 ms wave discharge

1 ms

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