Cycloheximide inhibits context memory and long-term habituation in the crab Chasmagnathus

Pedreira, Marı́a Eugenia; Dimant, Beatriz; Tomsic, Daniel; Quesada-Allué, Luis A.; Maldonado, Héctor

doi:10.1016/0091-3057(95)00124-f

Cited by 68 publications

(60 citation statements)

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“…First, crabs tested 24 h after being exposed for 2 h to the testing environment showed levels ofresponding to the phasic stimulus lower than those of a nonpreexposed group (Pedreira, Dimant, & Maldonado, 1996;Pedreira et al, 1995;Saraco & Maldonado, 1995;Tomsic et al, 1993). This effect, which we called the contextual memory effect, has also been observed in similar experiments with rats-although, in that case, it was described as a sensitization effect of the new environment on the nonpreexposed animals (see, e.g., Hall & Channell, 1985;Kom & Moyer, 1966).…”

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“…In the laboratory, upon sudden presentation of a rectangular screen passing overhead, the crab responds with a running reaction in an attempt to escape. The response declines over trials, and, after a single training session of 15 trials (1 h), the decrement persists for a long period (i.e., for 5 days, at least; Pedreira, Dimant, Tomsic, Quesada-Allue, & Maldonado, 1995). The response decrement has been shown to meet most of the parametric criteria ofhabituation (Brunner & Maldonado, 1988), to be stimulus specific (Lozada, Romano, & Maldonado, 1990;Romano, Lozada, & Maldonado, 1991), to be frequency specific (Lozada, 1993;Pedreira, Romano, Tomsic, Lozada, & Maldonado, 1998), and to be dependent on both age and the time of day (Pereyra, de la Iglesia, & Maldonado, 1996;Tomsic, Dimant, & Maldonado, 1996).…”

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Context-us association as a determinant of long-term habituation in the crabChasmagnathus

Tomsic

Pedreira

Romano

et al. 1998

Animal Learning & Behavior

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108

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An opaque screen moving overhead elicits an escape response in the crab Chasmagnathus that habituates for a long period after just a few presentations. A series of experiments was performed to determine whether the crab's long-term habituation (LTH) is mediated by an association between contextual cues and the eliciting stimulus, Chasmagnathus failed to exhibit LTH when a visual cue in the experimental environment was changed between training and testing, In addition, long-term exposure to the context in the absence ofthe eliciting stimulus impaired LTH, both when the exposure preceded the habituation training (latent inhibition) and when the exposure came after the training (extinction), Long exposure to the context alone prior to training also produced a decrease in responsiveness to the eliciting stimulus, which confirmed previous results. However, both effects of long exposure were only manifested when the crabs spent a period of time between exposure and testing out of the experimental context. The results of this paper are interpreted as supporting the view that Chasmagnathus LTH can be understood largely by Wagner's associative theory of habituation.

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confidence: 99%

Context-us association as a determinant of long-term habituation in the crabChasmagnathus

Tomsic

Pedreira

Romano

et al. 1998

Animal Learning & Behavior

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108

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“…Fifty µl of vehicle or drug solution was injected through the right side of the dorsal cephalothoracic-abdominal membrane by means of a syringe fitted with a sleeve to control depth of penetration to 4 mm, thus ensuring that the injected solution was released roughly at the center of the pericardial sac (e.g., [32][33][34]. A remarkable feature shared by all these experiments was that the effective drug doses given by systemic administration were manifestly low, i.e., equivalent to or even lower than doses administered by intracranial injection in vertebrates, e.g., cycloheximide (CYX) (12), actinomycin-D (ATY) (18), angiotensin II (35), enkephalin (33), serotonin (36). The relative simplicity of brain organization and the lack of an endothelial blood-brain barrier in crabs (37), together with the fact that blood is distributed throughout an extensive capillary system in various neuropil areas of the brain (38,39), may explain the low threshold for drug action.…”

Section: Pharmacological and Biochemical Experimentsmentioning

confidence: 98%

“…The flight reaction declines over various trials and the decrement persists for at least five days (11,12).…”

Section: An Automatic Device To Study Long-term Habituation In Crabsmentioning

confidence: 99%

“…Thus, a series of experiments was performed aimed at testing the effect of CYX and ATY on acquisition and retention of LTH (12,18). An injection of 10 µg of CYX inhibited incorporation of [ 14 C]-amino acids into brain protein by 88% for 2 h and 20 µg inhibited it by 92%, while 0.6 µg of ATY inhibited incorporation by 59.7% for 1 h, but no inhibition was found at 24 h postinjection in any case.…”

Section: Lth Is Blocked By Inhibitors Of Protein and Rna Synthesismentioning

confidence: 99%

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Long-term habituation (LTH) in the crab Chasmagnathus: a model for behavioral and mechanistic studies of memory

Maldonado¹,

Romano²,

Tomsic³

1997

Braz J Med Biol Res

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A decade of studies on long-term habituation (LTH) in the crab Chasmagnathus is reviewed. Upon sudden presentation of a passing object overhead, the crab reacts with an escape response that habituates promptly and for at least five days. LTH proved to be an instance of associative memory and showed context, stimulus frequency and circadian phase specificity. A strong training protocol (STP) (≥15 trials, intertrial interval (ITI) of 171 s) invariably yielded LTH, while a weak training protocol (WTP) (≤10 trials, ITI = 171 s) invariably failed. STP was used with a presumably amnestic agent and WTP with a presumably hypermnestic agent. Remarkably, systemic administration of low doses was effective, which is likely to be due to the lack of an endothelial blood-brain barrier. LTH was blocked by inhibitors of protein and RNA synthesis, enhanced by protein kinase A (PKA) activators and reduced by PKA inhibitors, facilitated by angiotensin II and IV and disrupted by saralasin. The presence of angiotensins and related compounds in the crab brain was demonstrated. Diverse results suggest that LTH includes two components: an initial memory produced by spaced training and mainly expressed at an initial phase of testing, and a retraining memory produced by massed training and expressed at a later phase of testing (retraining). The initial memory would be associative, context specific and sensitive to cycloheximide, while the retraining memory would be nonassociative, context independent and insensitive to cycloheximide. Key wordsSimple and basic models to study memory Simple-system approaches using invertebrate species have led to considerable progress in our understanding of the mechanisms underlying learning and memory (e.g., the mollusks Aplysia (1,2) and Hermissenda (3,4), the fruit fly Drosophila (5), and the honey bee Apis (6)). A virtue usually attributed to invertebrates is that they are simple models though the use of this term has been highly controversial. Indeed, the CNS of invertebrates cannot be considered simple from the perspective of a neural network researcher since the amount of neurons involved in a current mnemonic process is assumed to be far larger than that required to obtain a satis-

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Context Shift and Protein Synthesis Inhibition Disrupt Long-Term Habituation after Spaced, but Not Massed, Training in the CrabChasmagnathus

Hermitte

Pedreira

Tomsic

et al. 1999

Neurobiology of Learning and Memory

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Cycloheximide inhibits context memory and long-term habituation in the crab Chasmagnathus

Cited by 68 publications

References 34 publications

Context-us association as a determinant of long-term habituation in the crabChasmagnathus

Context-us association as a determinant of long-term habituation in the crabChasmagnathus

Long-term habituation (LTH) in the crab Chasmagnathus: a model for behavioral and mechanistic studies of memory

Context Shift and Protein Synthesis Inhibition Disrupt Long-Term Habituation after Spaced, but Not Massed, Training in the CrabChasmagnathus

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