Transformation of siphon responses during conditioning of Aplysia suggests a model of primitive stimulus-response association.

Walters, Edgar T.

doi:10.1073/pnas.86.19.7616

Cited by 27 publications

(15 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…First, they extend the findings of other studies showing that Aplysia was able to detect and learn about different chemosensory and tactile stimuli Carew et al, 1981;Colwill et a!., 1988;Walters et al, 1981). Second, they confirm previous reports documenting that Aplysia was sensitive to the temporal arrangements ofCSs and USs (Hawkins, Carew, & Kandel, 1986;Hawkins, Lalevic, Clark, & Kandel, 1989;Walters, 1989). It is especially impressive that responding was greater to the CS+ than to the CS -in each of the experiments reported here independently of the specific stimulus identities.…”

Section: Discussionsupporting

confidence: 80%

Pavlovian appetitive discriminative conditioning inAplysia californica

Colwill

Goodrum

Martin

1997

Animal Learning & Behavior

View full text Add to dashboard Cite

Three experiments demonstrated Pavlovian appetitive discrimination learning in the marine mollusc, Aplysia californica. In each experiment, subjects were exposed to two conditioned stimuli; one stimulus (CS+) was paired with food presentations and the other stimulus (CS-) was never followed by food. In Experiments 1 and 3 different chemosensory stimuli were used, and in Experiment 2 different tactile stimuli were used. For both types of conditioned stimuli, bite responses occurred significantly more often to the CS+ than to the CS-. Experiment 2 also showed that Aplysia could learn a reversal of this discrimination. Experiment 3 showed that nonreinforced presentations of CS+ resulted in a decline in the frequency of conditioned biting. The implications of these results for neurobiological analyses of learning are discussed.In a typical Pavlovian discriminative conditioning procedure, subjects are exposed to two conditioned stimuli (CSs) that differ in their temporal relation to an unconditioned stimulus (US). One of these stimuli (CS+) immediately precedes presentations of the US; the other stimulus (CS-) is never paired with that US. Differential responding to the CS+ and CS-is found to emerge over the course of discrimination training in various vertebrate (e.g., Hammond, 1967;Hoffman & Fitzgerald, 1982;Moore, 1972;Pavlov, 1927;Rescorla, 1980;Schneiderman, 1972) and invertebrate subjects (e.g., Bitterman, Menzel, Fietz, & Schafer, 1983;Block & McConnell, 1967;Fukushi, 1979;Nelson, 1971;Ricker, Brzorad, & Hirsch, 1986).Of particular interest are reports of Pavlovian discriminative conditioning in those invertebrates especially suited to a neurophysiological analysis of plasticity. Behavioral sensitivity to the differential treatments ofa CS+ and CS -has been found in several experiments using aversive USs with the marine mollusc Aplysia califomica , the leech Haemopis marmorata (Karrer & Sahley, 1988), and the terrestrial mollusc Limax maximus (Sahley, Gelperin, & Rudy, 1981). For example, in the leech, Karrer and Sahley (1988) paired one food (e.g., raw chicken) but not This research was supported by National Science Foundation Grant BNS-8922551 to R.M.C. and by funds from the Howard Hughes Medical Institute. K.G. and A.M. were supported by research fellowships awarded by Brown University's Early Identification Program. We thank Robin Absher and Emily Whitcomb for assistance with data collection. Experiment 1 was presented at the 65th Annual Meeting ofthe Eastern Psychological Association in Providence and at the Second Annual Summer Research Symposium at Brown University in August 1993. A brief description of Experiment 1 also appears in Colwill (1996). Reprint requests should be addressed to R. M. Colwill, Department of Psychology, Brown University, Box 1853, Providence, RI 02912 (e-mail: ruth_colwill@brown.edu).another food (e.g., raw liver) with a quinidine sulfate solution. On test trials, subjects were given a choice between raw beefand either the CS+ or the CS-foods. The preference for the CS+ relative ...

show abstract

Section: Discussionsupporting

confidence: 80%

Pavlovian appetitive discriminative conditioning inAplysia californica

Colwill

Goodrum

Martin

1997

Animal Learning & Behavior

View full text Add to dashboard Cite

show abstract

“…Behavioral conditioning in this preparation is similar to conditioning of siphon withdrawal in intact Aplysia (Carew et al, 1981) and conditioning of gill withdrawal in another simplified preparation , both of which display additional higher-order features that are characteristic of conditioning in vertebrates Hawkins et al, 1986Hawkins et al, , 1998Colwill et al, 1988a,b;Walters, 1989). With the siphon withdrawal preparation, it is relatively easy to examine behavioral conditioning while simultaneously monitoring PSPs between identified sensory and motor neurons that contribute to the behavior.…”

Section: Discussionmentioning

confidence: 99%

“…Conditioning of the withdrawal reflex has many of the behavioral features characteristic of conditioning in mammals, including stimulus specificity , response specificity Walters, 1989), temporal specificity and effects of contingency (Hawkins et al, 1986), as well as several effects of context (Colwill et al, 1988a,b) and both forward and simultaneous second-order conditioning . These behavioral results suggest that conditioning in Aplysia and in mammals may share common cellular and molecular mechanisms.…”

Section: Abstract: Aplysia; Classical Conditioning; Synaptic Plasticmentioning

confidence: 99%

The Contribution of Activity-Dependent Synaptic Plasticity to Classical Conditioning inAplysia

et al. 2001

View full text Add to dashboard Cite

Plasticity at central synapses has long been thought to be the most likely mechanism for learning and memory, but testing that idea experimentally has proven to be difficult. For this reason, we have developed a simplified preparation of the Aplysia siphon withdrawal reflex that allows one to examine behavioral learning and memory while simultaneously monitoring synaptic connections between individual identified neurons in the CNS. We previously found that monosynaptic connections from LE siphon sensory neurons to LFS siphon motor neurons make a substantial contribution to the reflex in the siphon withdrawal preparation (Antonov et al., 1999a). We have now used that preparation to assess the contribution of various cellular mechanisms to classical conditioning of the reflex with a siphon tap conditioned stimulus (CS) and tail shock unconditioned stimulus (US). We find that, compared with unpaired training, paired training with the CS and US produces greater enhancement of siphon withdrawal and evoked firing of LFS neurons, greater facilitation of the complex PSP elicited in an LFS neuron by the siphon tap, and greater facilitation of the monosynaptic PSP elicited by stimulation of a single LE neuron. Moreover, the enhanced facilitation of monosynaptic LE-LFS PSPs is greater for LE neurons that fire during the siphon tap and correlates significantly with the enhancement of siphon withdrawal and evoked firing of the LFS neurons. These results provide the most direct evidence to date that activitydependent plasticity at specific central synapses contributes to behavioral conditioning and support the idea that synaptic plasticity is a mechanism of learning and memory more generally.

show abstract

“…First, a number of studies have shown that the topography of the CR depends upon the identity of the US Hawkins, Lalevic, Clark, & Kandel, 1989;Jenkins & Moore, 1973;LaMon & Zeigler, 1984;Skelton, Spetch, & Wilkie, 1980;Spetch, Wilkie, & Skelton, 1981;Walters, 1989). In a classic study of autoshaping, Jenkins and Moore (1973) observed that the response to the CS captured features characteristic of the response to the US paired with that CS.…”

Section: Discussionmentioning

confidence: 99%