Classical conditioning in a simple withdrawal reflex in Aplysia californica

Carew, TJ; Walters, E. T.; Kandel, ER

doi:10.1523/jneurosci.01-12-01426.1981

Cited by 266 publications

(183 citation statements)

References 30 publications

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“…ZD7288 (100 μM) did not have significant effects on the amplitude of the initial siphon withdrawal in response to either the siphon tap CS or tail shock US. ZD7288 also did not have a significant effect on the change in response to the CS following unpaired training (F[1,44] = 1.48, NS overall and at each test), which is a nonassociative protocol that produces results intermediate between training with the CS alone (habituation) or US alone (sensitization), and can be thought of as a combination of the two (56,57). However, ZD7288 significantly reduced the difference between paired and unpaired training, or conditioning (average = 23% of control, F[1,44] = 7.26, P < 0.01 for the interaction of drug and pairing overall and P < 0.05 onetail at each test).…”

Section: Hcn Channels Contribute To Behavioral Conditioning But Notmentioning

confidence: 99%

Hyperpolarization-activated, cyclic nucleotide-gated cation channels in Aplysia : Contribution to classical conditioning

Yang

Kuzyk

Antonov

et al. 2015

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

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Hyperpolarization-activated, cyclic nucleotide-gated cation (HCN) channels are critical regulators of neuronal excitability, but less is known about their possible roles in synaptic plasticity and memory circuits. Here, we characterized the HCN gene organization, channel properties, distribution, and involvement in associative and nonassociative forms of learning in Aplysia californica. Aplysia has only one HCN gene, which codes for a channel that has many similarities to the mammalian HCN channel. The cloned acHCN gene was expressed in Xenopus oocytes, which displayed a hyperpolarization-induced inward current that was enhanced by cGMP as well as cAMP. Similarly to its homologs in other animals, acHCN is permeable to K + and Na + ions, and is selectively blocked by Cs + and ZD7288. We found that acHCN is predominantly expressed in inter-and motor neurons, including LFS siphon motor neurons, and therefore tested whether HCN channels are involved in simple forms of learning of the siphon-withdrawal reflex in a semiintact preparation. ZD7288 (100 μM) significantly reduced an associative form of learning (classical conditioning) but had no effect on two nonassociative forms of learning (intermediate-term sensitization and unpaired training) or baseline responses. The HCN current is enhanced by nitric oxide (NO), which may explain the postsynaptic role of NO during conditioning. HCN current in turn enhances the NMDA-like current in the motor neurons, suggesting that HCN channels contribute to conditioning through this pathway.HCN channels | learning and memory | NMDA | nitric oxide | Aplysia H yperpolarization-activated, cyclic nucleotide-gated (HCN), cation nonselective ion channels generate hyperpolarization-activated inward currents (I h ) and thus tend to stabilize membrane potential (1-3). In addition, binding of cyclic nucleotides (cAMP and cGMP) to the C-terminal cyclic nucleotide binding domain (CNBD) enhances I h and thus couples membrane excitability with intracellular signaling pathways (2, 4). HCN channels are widely important for numerous systemic functions such as hormonal regulation, heart contractility, epilepsy, pain, central pattern generation, sensory perception (4-15), and learning and memory (16-24).However, in previous studies it has been difficult to relate the cellular effects of HCN channels directly to their behavioral effects, because of the immense complexity of the mammalian brain. We have therefore investigated the role of HCN channels in Aplysia, which has a numerically simpler nervous system (25). We first identified and characterized an HCN gene in Aplysia, and showed that it codes for a channel that has many similarities to the mammalian HCN channel. We found that the Aplysia HCN channel is predominantly expressed in motor neurons including LFS neurons in the siphon withdrawal reflex circuit (26, 27). We therefore investigated simple forms of learning of that reflex in a semiintact preparation (28-30) and found that HCN current is involved in classical conditioning and enhances the ...

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Section: Hcn Channels Contribute To Behavioral Conditioning But Notmentioning

confidence: 99%

Hyperpolarization-activated, cyclic nucleotide-gated cation channels in Aplysia : Contribution to classical conditioning

Yang

Kuzyk

Antonov

et al. 2015

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

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“…It should be possible to answer this question by comparing the neural mechanisms of the different forms of learning, ideally in the same preparation. The gill-and siphon-withdrawal reflex of Aplysia has been useful for such studies, because it exhibits several forms of learning including habituation, dishabituation, sensitization, and classical conditioning (Pinsker et al, 1970;Carew et al, 1971Carew et al, , 1981, and it is amenable to cellular analysis. Studies of the cellular mechanisms of learning in Aplysia have revealed both similarities and differences between the mechanisms contributing to dishabituation and sensitization (Carew et al, 1971;Wright et al, 1991;Cohen et al, 1997;Antonov et al, 1999) and also between those contributing to sensitization and classical conditioning (Hawkins et al, 1993;Antonov et al, 2001Antonov et al, , 2003Li et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Operant Conditioning of Gill Withdrawal inAplysia

2006

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A basic question in neuroscience is how different forms of learning are related. To further address that question, we examined whether gill withdrawal in Aplysia, which has already been studied extensively for neuronal mechanisms contributing to habituation, sensitization, and classical conditioning, also undergoes operant conditioning. Animals were run in pairs. During the initial training period, the contingent (experimental) animal received a siphon shock each time its gill relaxed below a criterion level, and the yoked control animal received a shock whenever the experimental animal did, regardless of its own gill position. This was followed by an extinction period when there was no shock, a retraining period when both animals were contingent, and another extinction period. The experimental animals spent more time with their gills contracted above the criterion level than did the control animals during each period, demonstrating operant conditioning. The type of gill behavior modified by learning shifted over time: the experimental animals had a larger increase in the frequency and duration of spontaneous contractions than did the control animals during the first but not the last extinction period and a larger increase in the level of tonic contraction during the last but not the first extinction period. Because many of the neurons controlling spontaneous and tonic gill withdrawal have already been identified, it should now be possible to examine the cellular locus and mechanism of operant conditioning and compare them with those for other forms of learning of the same behavior.

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“…In neurobiology Aplysia has been often used for investigating classical and operant conditioning (Carew & Walters & Kandel, 1981). Consider a slightly simplified classical conditioning experiment of the Aplysia's defensive withdrawal reflex.…”

Section: Simulation Of Adaptive Agent Behaviormentioning

confidence: 99%