Learning: A Model System for Physiological Studies

Mpitsos, George J.; Collins, Stephen; McClellan, Andrew D.

doi:10.1126/science.622551

Cited by 89 publications

(32 citation statements)

References 48 publications

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“…Animals trained with squid as the CSϩ showed dramatically increased response latencies to squid, still apparent 8 days after training. The results of this study and earlier ones (Mpitsos, Collins, & McClellan, 1978;Mpitsos & Davis, 1973) were robust and clear. Prior to training, bite/strike latencies to squid were ~2-3 sec; 1 and 8 days following conditioning, the latencies were ~75 and 48 sec, respectively.…”

Section: Nonassociative Influences In Chemosensory Learning Paradigmssupporting

confidence: 61%

“…This pattern is consistent with what one might expect if satiation/habituation/sensory adaptation were at work, as in our Experiment 4. Similarly, Mpitsos et al (1978, Figure 13) reported that CS-alone presentations (squid extract) resulted in elevated thresholds for bite/strike behaviors in Pleurobranchaea, when assessed 12 h after training, but had returned to nearbaseline levels at a 24-h retention interval.…”

Section: Nonassociative Influences In Chemosensory Learning Paradigmsmentioning

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: Nonassociative Influences In Chemosensory Learning Paradigmssupporting

confidence: 61%

Section: Nonassociative Influences In Chemosensory Learning Paradigmsmentioning

confidence: 99%

Chemosensory conditioning in molluscs: II. A critical review

Farley

Jin

Huang

et al. 2004

Learning & Behavior

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“…Hermrninda can learn to associate photic and vestibular inputs (13). A neural correlate of food avoidance conditioning by using shock as the aversive stimulus has been described in Pleurobranchaea (14,15). This concerted effort combined with our ability to train isolated brains while recording cellular interactions gives real hope for progress in unraveling the synaptic fabric underlying associative learning.…”

Section: Abstracimentioning

confidence: 99%

Rapid taste-aversion learning by an isolated molluscan central nervous system.

Chang¹,

Gelperin²

1980

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

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ABSTRACIThe isolated lips and nervous system of the terrestrial slug Limaxm us will produce some of the feeding behavior of the intact animal; i.e., they generate the rhythmic neural activity characteristic of ingestion in respnse to food extracts applied to the lips. This preparation will respond to a variety of food extracts that elicit feeding in the wholre animal.This provides the opportunity for aversive conditioning experiments involving taste discrimination. Pairing lip chemostimulation by attractive food extracts with lip chemostimulation by using bitter plant secondary substances can cause the isolated brain to selectively suppress its neural response to one food extract while remaining responsive to another. Such isolated brains can learn after one or two trials and retain the learning for more than 8 hr.The terrestrial slug Linmx maximus can show one-trial food avoidance learning lasting 3 weeks (1). A physiological analysis of the synaptic events causally related to this learning would be greatly aided if one could train the isolated brain to alter its food-related chemosensory input-motor output pathways in a manner analogous to the learning shown by the intact animal Here we report that the isolated central nervous system shows a form of learning analogous to that displayed by the intact slug.The most strildng change in behavior shown by an intact slug when it learns to avoid a new food is an alteration in directed locomotion in response to food odor. The food stimuli we have conditioned slugs to avoid are inherently very attractive. Naive, hungry Limax rapidly orient to and approach food items such as potatoes, carrots, and mushrooms (2, 3). Slugs conditioned by toxicosis to avoid these food items typically will not orient to or approach the odor source (i.e., the food item) (1). Thus, learning alters the olfactory input-pedal locomotor output pathway. Although the olfactory input (4) and locomotor output (5, 6) have been partially characterized, a related pathway from lip chemoreceptors to feeding motoneurons is much more amenable to physiological analysis. Therefore we decided to condition the feeding pathway to produce experience-dependent alterations that would be analogous to refusal to feed in the intact animal.A lip-brain-buccal ganglia preparation will reliably generate reproducible bouts of feeding motor program (FMP) in response to brief standardized chemostimuli applied to the lips (7,8). The ease of stimulus control and the unambiguous nature of the neural output pattern led us to use this preparation to produce an in vitro analog of the in vivo learning.Slugs were reared by using an enriched artificial diet (8). The entire central nervous system with the lip region was removed from a slug such that the three lip nerves (external, medial, and internal) retained their peripheral and central connections. TheThe publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 ...

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“…Second, although the majority of this work with Hermissenda has focused on associations between discrete visual (light) and vestibular (rotation) stimuli, Hermissenda also exhibits the complex chemosensory responsivity characteristic of most mollusks (Agersborg, 1922(Agersborg, , 1925, providing for the opportunity to use chemosensory stimuli as the defining feature of the experimental context. As with many other invertebrates (Colwill et aI., I988a;Croll & Chase, 1977Mpitsos, Collins, & McClellan, 1978;Sahley, Martin, & Gelperin, 1990Sahley et aI., 198 I), Hermissenda is highly responsive to chemosensory cues and will rapidly learn about their role as discriminative stimuli (Farley et aI., 1990). Finally, the visual, vestibular, and chemosensory pathways in Hermissenda have been subjected to extensive neurophysiological analysis and are known to interact synaptically (e.g., Alkon, Akaike, & Harrigan, 1978), thus providing the opportunity for future examination of the interaction between discrete visual-vestibular associations and chemosensory-based contextual cues.…”

mentioning

confidence: 99%

Chemosensory-based contextual conditioning inHermissenda crassicornis

Rogers

Schiller

Matzel

1996

Animal Learning & Behavior

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In two experiments, the marine mollusk Hermissenda crassicornis was exposed to context discrimination training. In one context, defined by the presence of a diffuse chemosensory stimulus (shellfish extract A), brief, unsignaled, unconditioned stimuli (USs; high-speed rotation) were presented; in a second context, defined by the presence of shellfish extract B, no USs were presented. Animals were then tested (at both 1.5 and 24 h) by exposing them to small pieces of the shellfish meat used to define the two contexts. The latency to strike at the meat served as an index of the context-US association. In Experiment 1, the latency to strike at the cue associated with rotation was reduced relative to both preconditioning strike latencies and the associatively neutral cue. However, in a two-choice test where the animals could approach the conditioned or neutral stimulus, the animals regularly avoided the stimulus paired with rotation. Moreover, if, following conditioning, the animals were presented with an unsignaled rotation in the conditioned context or the neutral context, the animals exhibited more effective defensive clinging (an unconditioned reflex normally elicited by rotation) in the conditioned context, suggesting that it "prepared" the animal for the aversive US. In total, these results demonstrate that Hermissenda is capable of making associations to diffuse background (contextual) stimuli. Moreover, the results suggest that pairing the chemosensory cue with an aversive USelicits a strike response in Hermissenda when the animal is placed in forced contact with the cue and an active avoidance response when the animal can choose between that cue and a neutral cue.

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Learning: A Model System for Physiological Studies

Cited by 89 publications

References 48 publications

Chemosensory conditioning in molluscs: II. A critical review

Chemosensory conditioning in molluscs: II. A critical review

Rapid taste-aversion learning by an isolated molluscan central nervous system.

Chemosensory-based contextual conditioning inHermissenda crassicornis

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