Neurophysiological Substrates of Context Conditioning in Hermissenda Suggest a Temporally Invariant Form of Activity-Dependent Neuronal Facilitation

Talk, Andrew C.; Muzzio, Isabel A.; Matzel, Louis D.

doi:10.1006/nlme.1998.3890

Cited by 4 publications

(5 citation statements)

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“…More recently, Talk, Muzzio, and Matzel (1999) reported contextual conditioning to an environment whose distinguishing feature was that it was continuously illuminated. Hermissenda confined to one half of an illuminated alleyway for 15 min (the lit context) and exposed therein to repeated, brief, unsignaled, orbital rotations later avoided this lit context in a choice test and increased their time spent in the other half of the alleyway, which was dark.…”

Section: Additional Reports Of Contextual Conditioning In Hermissendamentioning

confidence: 99%

“…Second, the distinction between a discrete and a contextconditioning trial may break down in the training paradigm used by Talk et al (1999), where 60 repeated pulses of 3 sec of orbital rotation were delivered every 15 sec (a relatively high frequency). Vigorous orbital rotation dislodges animals from their substrate (Alkon, 1974), subjecting them to considerable turbulence and mechanosensory stimulation that outlasts the termination of rotation.…”

Section: Additional Reports Of Contextual Conditioning In Hermissendamentioning

confidence: 99%

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Chemosensory conditioning in molluscs: II. A critical review

Farley

Jin

Huang

et al. 2004

Learning & Behavior

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We critically review chemosensory conditioning studies with molluscs and find that, in many studies, the influence of nonassociative processes complicates, obscures, and renders ambiguous the unique contribution of associative learning. These nonassociative processes include sensory adaptation, habituation, sensitization, and changes in feeding motivation. They arise from both the food extracts that have often been used as conditioned stimuli and the aversive stimuli that have been used as unconditioned stimuli.

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Section: Additional Reports Of Contextual Conditioning In Hermissendamentioning

confidence: 99%

Section: Additional Reports Of Contextual Conditioning In Hermissendamentioning

confidence: 99%

Chemosensory conditioning in molluscs: II. A critical review

Farley

Jin

Huang

et al. 2004

Learning & Behavior

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“…Bryo, a macrolide lactone, has efficacy in subnanomolar concentrations (22)(23)(24). Like phorbol esters and the endogenous activator diacylglycerol, Bryo binds to the C1 domain within PKC and causes its translocation to membranes, which is then followed by down-regulation (25,26).…”

mentioning

confidence: 99%

Protein synthesis required for long-term memory is induced by PKC activation on days before associative learning

Alkon

Epstein

Kuzirian

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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Protein synthesis has long been known to be required for associative learning to consolidate into long-term memory. Here we demonstrate that PKC isozyme activation on days before training can induce the synthesis of proteins necessary and sufficient for subsequent long-term memory consolidation. Bryostatin (Bryo), a macrolide lactone with efficacy in subnanomolar concentrations and a potential therapeutic for Alzheimer's disease, is a potent activator of PKC, some of whose isozymes undergo prolonged activation after associative learning. Under normal conditions, two training events with paired visual and vestibular stimuli cause short-term memory of the mollusc Hermissenda that lasts Ϸ7 min. However, after 4-h exposures to Bryo (0.25 ng͞ml) on two preceding days, the same two training events produced long-term conditioning that lasted >1 week and that was not blocked by anisomycin (1 g͞ml). Anisomycin, however, eliminated long-term memory lasting at least 1 week after nine training events. Both the nine training events alone and two Bryo exposures plus two training event regimens caused comparably increased levels of the PKC ␣-isozyme substrate calexcitin in identified type B neurons and enhanced PKC activity in the membrane fractions. Furthermore, Bryo increased overall protein synthesis in cultured mammalian neurons by up to 60% for >3 days. The specific PKC antagonist Ro-32-0432 blocked much of this Bryo-induced protein synthesis as well as the Bryo-induced enhancement of the behavioral conditioning. Thus, Bryo-induced PKC activation produces those proteins necessary and sufficient for long-term memory on days in advance of the training events themselves.bryostatin ͉ PKC isozymes T he requirement of protein synthesis for long-term memory has been demonstrated over several decades for a variety of memory paradigms (1-14). It was originally shown that druginduced inhibition of protein synthesis (e.g., with 5-propyluracil or anisomycin) blocked long-term memory when this inhibition occurred during a critical time interval after the training paradigm (9). It has remained a mystery as to what specific, critical proteins were so essential for memory consolidation and how their molecular regulation was so necessary for long-lasting memory storage.In many species the formation of long-term associative memory has also been shown to depend on translocation, and thus activation, of protein kinase C (PKC) isozymes to neuronal membranes. PKC activation has been shown to occur in single identified type B cells of the mollusc Hermissenda (15) with Pavlovian conditioning and a variety of mammalian associative learning protocols (16)(17)(18). Furthermore, a high-affinity substrate of the ␣-isozyme of PKC, calexcitin (CE) (19), was found within single identified type B cells to show Pavlovianconditioning-dependent increases of phosphorylation and absolute quantity (20).Consistent with these findings, administration of the potent PKC activator bryostatin (Bryo) enhanced rat spatial maze learning (21). Bryo, a macrolide lactone,...

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“…Aplysia tested in the same context in which they had received electric shocks exhibited signi cantly greater siphon withdrawal than those tested in the control context. In another study, (Talk et al 1999) demonstrated aversive context conditioning leading to avoidance of the paired context. They exposed Hermissenda to aversive high-speed orbital rotation while restricted to either the lit or darkened side of a light-dark preference box.…”

Section: Discussionmentioning

confidence: 96%

“…Scientists have argued for the existence of anxiety-like behavioral conditions in gastropod mollusks at least since the initial demonstrations of aversive conditioning in Aplysia (Kandel 1983). Anxiety-like behavior has been most clearly demonstrated in marine gastropod mollusks during aversive context conditioning of Aplysia Californica (Colwill et al 1988) and Hermissenda crassicornis (Talk et al 1999). In these studies, a context was paired with an aversive stimulus.…”

Section: Discussionmentioning

confidence: 99%

Mechanisms of Anxiety-Like Behavior in the Great Ramshorn Snail (Planorbarius corneus)

Talk,

Vanatheeva

2024

Preprint

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Like vertebrate animals, some invertebrates have been shown to exhibit anxiety-like behavior while in apparatus that allow choice between sheltered, darkened spaces and open, lit spaces. The behavioral mechanisms by which invertebrates accomplish anxiety-like behavior, and whether those mechanisms are similar across species, has not been fully studied. Across three experiments, we investigated possible behaviors (photokinesis, phototaxis, and sheltering) that Great Ramshorn snails (Planorbarius corneus) could use to accomplish anxiety-like behavior while in presence of the odor of a predatory fish. In experiment one, we used a light/dark preference box to demonstrate reduced preference for exposed and lit areas caused by the predator odor. In experiment two, we used an open field apparatus to demonstrate an increase in refuge-seeking (time spent near a wall) in diffusely lit but not dark environments caused by predator odor. In the same experiment we saw no effect of predator odor on photokinesis (difference in movement speed in a lit versus dark environment). In experiment three, we conducted a second open field study with a directional light source and found no evidence of phototaxis (movement direction with respect to light), and no effect of predator odor on phototaxis. Thus, in our studies we found evidence for refuge-seeking as a mechanism for anxiety-like behavior in the presence of predator odor and little evidence for perhaps more computationally simple strategies of increased photokinesis and phototaxis.

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Neurophysiological Substrates of Context Conditioning in Hermissenda Suggest a Temporally Invariant Form of Activity-Dependent Neuronal Facilitation

Cited by 4 publications

References 78 publications

Chemosensory conditioning in molluscs: II. A critical review

Chemosensory conditioning in molluscs: II. A critical review

Protein synthesis required for long-term memory is induced by PKC activation on days before associative learning

Mechanisms of Anxiety-Like Behavior in the Great Ramshorn Snail (Planorbarius corneus)

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