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Aron Weller - One of the best experts on this subject based on the ideXlab platform.

  • Examining the role of cholecystokinin in Appetitive Learning in the infant rat.
    Peptides, 2001
    Co-Authors: Aron Weller, Ludmila Tsitolovskya, Iris Gispan, Sharon Rabinovitz
    Abstract:

    The role of Cholecystokinin (CCK), a gut hormone and neuropeptide, in early Learning was examined. Pairing a novel odor (presented away from the nest) with exogenously administered CCK (0.25 & 0.5 microg/kg IP) has been shown to produce a conditioned-odor preference in infant rats (Weller, A.; Blass, E.M. Behav. Neurosci. 104:199-206; 1990). This suggests that CCK can act as a positive unconditioned stimulus (UCS). In the present study the possibility that CCK mediates Learning was examined in 12-day-old rats, using rewards that represent aspects of the dam and the nest. In Experiments 1 and 2, pups received the selective CCK1 receptor antagonist devazepide (600 microg/kg), the selective CCK2 receptor antagonist L365,260 (600 microg/kg), or vehicle. In a series of training trials, choosing a particular floor texture was rewarded by 20 sec. on a rug texture (experiment 1) or with maternal (feces) odor (experiment 2). In experiment 3, after administering devazepide (0, 600, or 1000 microg/kg) a novel odor was paired once with reunion of the pup with its dam. The dependent measure in all studies was the pup's relative preference toward the (tactile or olfactory) conditioned stimulus (CS), determined in preference tests. Conditioned preferences were evident in all experiments. The CCK receptor antagonists did not increase conditioned preference levels. L365, 260 (experiment 2) and devazepide (experiment 1) clearly blocked the appearance of the conditioned effect in one of the experiments. In addition, devazepide treatment eliminated the conditioned effect in the two other experiments, by increasing preference levels in the control groups. In summary, the results suggest that endogenous CCK mediates some aspects of the infant's acquisition of new associations. The role of the two receptor-subtypes appears to be different, depending on the context and the nature of the rewarding stimulus.

  • The influence of natural preference for tactile stimuli on Appetitive Learning in rat pups.
    Developmental psychobiology, 1997
    Co-Authors: Shelly Rakover-atar, Aron Weller
    Abstract:

    Stimuli of the same modality tend to be organized along a "natural preference scale." This study examined the ability of six- and nine-day-old rat pups to acquire Appetitive Learning, when the CS was one of two differently "naturally preferred" tactile stimuli (floor textures: rug and plywood). In Experiment 1, all pups showed a relative natural preference for the rug texture over the plywood texture. Pups conditioned on the plywood texture (exposed to a sibling pup as the US) showed a robust increase in preference for the conditioned texture whereas pups conditioned on the rug texture showed a different and more moderate pattern of acquisition. Developmental differences were found only in extinction of the conditioned response: six-day-old (but not nine-day-old) pups displayed extinction of the response over four trials. Experiment 2 indicated that preexposure to the rug CS prior to conditioning (latent inhibition) did not interfere with the Learning process on the rug texture. Two major alternative explanations for the differential Learning patterns are discussed: motivational and catecholaminergic influences on Learning. The results suggest that natural preferences may modulate early Learning and memory processes.

  • the influence of natural preference for tactile stimuli on Appetitive Learning in rat pups
    Developmental Psychobiology, 1997
    Co-Authors: Shelly Rakoveratar, Aron Weller
    Abstract:

    Stimuli of the same modality tend to be organized along a “natural preference scale.” This study examined the ability of six- and nine-day-old rat pups to acquire Appetitive Learning, when the CS was one of two differently “naturally preferred” tactile stimuli (floor textures: rug and plywood). In Experiment 1, all pups showed a relative natural preference for the rug texture over the plywood texture. Pups conditioned on the plywood texture (exposed to a sibling pup as the US) showed a robust increase in preference for the conditioned texture whereas pups conditioned on the rug texture showed a different and more moderate pattern of acquisition. Developmental differences were found only in extinction of the conditioned response: six-day-old (but not nine-day-old) pups displayed extinction of the response over four trials. Experiment 2 indicated that preexposure to the rug CS prior to conditioning (latent inhibition) did not interfere with the Learning process on the rug texture. Two major alternative explanations for the differential Learning patterns are discussed: motivational and catecholaminergic influences on Learning. The results suggest that natural preferences may modulate early Learning and memory processes. © 1997 John Wiley & Sons, Inc. Dev Psychobiol 30: 29–30, 1997

Bennett G Galef - One of the best experts on this subject based on the ideXlab platform.

Makoto Mizunami - One of the best experts on this subject based on the ideXlab platform.

  • Roles of dopamine neurons in mediating the prediction error in aversive Learning in insects
    Scientific reports, 2017
    Co-Authors: Kanta Terao, Makoto Mizunami
    Abstract:

    In associative Learning in mammals, it is widely accepted that the discrepancy, or error, between actual and predicted reward determines whether Learning occurs. The prediction error theory has been proposed to account for the finding of a blocking phenomenon, in which pairing of a stimulus X with an unconditioned stimulus (US) could block subsequent association of a second stimulus Y to the US when the two stimuli were paired in compound with the same US. Evidence for this theory, however, has been imperfect since blocking can also be accounted for by competitive theories. We recently reported blocking in classical conditioning of an odor with water reward in crickets. We also reported an “auto-blocking” phenomenon in Appetitive Learning, which supported the prediction error theory and rejected alternative theories. The presence of auto-blocking also suggested that octopamine neurons mediate reward prediction error signals. Here we show that blocking and auto-blocking occur in aversive Learning to associate an odor with salt water (US) in crickets, and our results suggest that dopamine neurons mediate aversive prediction error signals. We conclude that the prediction error theory is applicable to both Appetitive Learning and aversive Learning in insects.

  • Roles of octopaminergic and dopaminergic neurons in mediating reward and punishment signals in insect visual Learning.
    The European journal of neuroscience, 2006
    Co-Authors: Sae Unoki, Yukihisa Matsumoto, Makoto Mizunami
    Abstract:

    Insects, like vertebrates, have considerable ability to associate visual, olfactory or other sensory signals with reward or punishment. Previous studies in crickets, honey bees and fruit-flies have suggested that octopamine (OA, invertebrate counterpart of noradrenaline) and dopamine (DA) mediate various kinds of reward and punishment signals in olfactory Learning. However, whether the roles of OA and DA in mediating positive and negative reinforcing signals can be generalized to Learning of sensory signals other than odors remained unknown. Here we first established a visual Learning paradigm in which to associate a visual pattern with water reward or saline punishment for crickets and found that memory after aversive conditioning decayed much faster than that after Appetitive conditioning. Then, we pharmacologically studied the roles of OA and DA in Appetitive and aversive forms of visual Learning. Crickets injected with epinastine or mianserin, OA receptor antagonists, into the hemolymph exhibited a complete impairment of Appetitive Learning to associate a visual pattern with water reward, but aversive Learning with saline punishment was unaffected. By contrast, fluphenazine, chlorpromazine or spiperone, DA receptor antagonists, completely impaired aversive Learning without affecting Appetitive Learning. The results demonstrate that OA and DA participate in reward and punishment conditioning in visual Learning. This finding, together with results of previous studies on the roles of OA and DA in olfactory Learning, suggests ubiquitous roles of the octopaminergic reward system and dopaminergic punishment system in insect Learning.

  • Participation of octopaminergic reward system and dopaminergic punishment system in insect olfactory Learning revealed by pharmacological study.
    The European journal of neuroscience, 2005
    Co-Authors: Sae Unoki, Yukihisa Matsumoto, Makoto Mizunami
    Abstract:

    Biogenic amines play major roles in the regulation of behavior in vertebrates and invertebrates. Previous studies in honey bees and fruit-flies Drosophila suggested that octopamine (OA, invertebrate counterpart of noradrenaline) and dopamine (DA) participate in Appetitive olfactory conditioning with sucrose reward and aversive olfactory conditioning with electric shock punishment, respectively. In order to determine whether the effects of the two chatecholamines on electric shock and sugar Learning can be generalized to other kinds of Appetitive and aversive reinforcers, we studied the effects of OA and DA receptor antagonists on Appetitive olfactory Learning with water reward, and aversive olfactory Learning with saline punishment in the cricket Gryllus bimaculatus. Crickets injected with epinastine or mianserin, OA receptor antagonists, into the hemolymph exhibited an impairment of Appetitive Learning with water reward, while aversive Learning with saline punishment remained intact. In contrast, fluphenazine, chlorpromazine or spiperone, DA receptor antagonists, impaired aversive Learning without affecting Appetitive Learning. This finding, combined with findings in previous studies, suggests that the octopaminergic reward system and dopaminergic punishment system participate in insect olfactory Learning with various Appetitive and aversive reinforcements.

Thomas Preat - One of the best experts on this subject based on the ideXlab platform.

  • two pairs of mushroom body efferent neurons are required for Appetitive long term memory retrieval in drosophila
    Cell Reports, 2013
    Co-Authors: Pierreyves Placais, Hiromu Tanimoto, Severine Trannoy, Anja B Friedrich, Thomas Preat
    Abstract:

    One of the challenges facing memory research is to combine network- and cellular-level descriptions of memory encoding. In this context, Drosophila offers the opportunity to decipher, down to single-cell resolution, memory-relevant circuits in connection with the mushroom bodies (MBs), prominent structures for olfactory Learning and memory. Although the MB-afferent circuits involved in Appetitive Learning were recently described, the circuits underlying Appetitive memory retrieval remain unknown. We identified two pairs of cholinergic neurons efferent from the MB α vertical lobes, named MB-V3, that are necessary for the retrieval of Appetitive long-term memory (LTM). Furthermore, LTM retrieval was correlated to an enhanced response to the rewarded odor in these neurons. Strikingly, though, silencing the MB-V3 neurons did not affect short-term memory (STM) retrieval. This finding supports a scheme of parallel Appetitive STM and LTM processing.

  • pka dynamics in a drosophila Learning center coincidence detection by rutabaga adenylyl cyclase and spatial regulation by dunce phosphodiesterase
    Neuron, 2010
    Co-Authors: Nicolas Gervasi, P Tchenio, Thomas Preat
    Abstract:

    Summary The dynamics of PKA activity in the olfactory Learning and memory center, the mushroom bodies (MBs), are still poorly understood. We addressed this issue in vivo using a PKA FRET probe. Application of dopamine, the main neuromodulator involved in aversive Learning, resulted in PKA activation specifically in the vertical lobe, whereas octopamine, involved in Appetitive Learning, stimulated PKA in all MB lobes. Strikingly, MB lobes were homogeneously activated by dopamine in the Learning mutant dunce , showing that Dunce phosphodiesterase plays a major role in the spatial regulation of cAMP dynamics. Furthermore, costimulation with acetylcholine and either dopamine or octopamine led to a synergistic activation of PKA in the MBs that depends on Rutabaga adenylyl cyclase. Our results suggest that Rutabaga acts as a coincidence detector and demonstrate the existence of subcellular domains of PKA activity that could underlie the functional specialization of MB lobes in aversive and Appetitive Learning.

H. Savage - One of the best experts on this subject based on the ideXlab platform.

  • Appetitive Learning Using Visual Conditioned Stimuli in the Pond Snail, Lymnaea
    Neurobiology of learning and memory, 2000
    Co-Authors: Richard J. Andrew, H. Savage
    Abstract:

    Feeding can be conditioned in the pond snail Lymnaea stagnalis to two different visual stimuli (a black panel or a 5-mm black and white check surround) by pairing the potential conditioned stimulus (CS) with sucrose. Exclusion of chemical cues (associated with differences between the water in home tank and that in training apparatus) that could serve as CS is important for successful visual conditioning. A featureless gray surround, used as an alternative to the check (to which it was matched in luminance) in counterbalanced training designs, was discriminated from the check, showing that resolution (for which the eyes would be necessary) was occurring. The gray surround was largely ineffective as a CS. Single-trial Learning was possible with the black panel, but not with the check; it is argued that this may be due to lack of prior experience of stimuli like the check. Conditioning of feeding has now been obtained in Lymnaea to chemical, tactile, and visual cues, opening the way to comparative studies of the neural circuitry underlying Appetitive conditioning in different senses, so far explored in Lymnaea only for tactile CS. Such comparative studies are as yet largely lacking in invertebrates.