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Roles of octopamine and dopamine in appetitive and aversive memory acquisition studied in olfactory conditioning of maxillary palpi extension response in crickets.

Matsumoto Y, Matsumoto CS, Wakuda R, Ichihara S, Mizunami M - Front Behav Neurosci (2015)

Bottom Line: In fruit-flies, however, it was concluded that dopamine mediates both appetitive and aversive reinforcement, which differs from our suggestion in crickets.Crickets extended their maxillary palpi and vigorously swung them when they perceived some odors, and we found that crickets that received pairing of an odor with water reward or sodium chloride punishment exhibited an increase or decrease in percentages of maxillary palpi extension responses to the odor.Using this procedure, we found that octopamine and dopamine receptor antagonists impair acquisition of appetitive and aversive learning, respectively.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Science, Hokkaido University Sapporo, Japan ; Faculty of Liberal Arts, Tokyo Medical and Dental University Ichikawa, Japan.

ABSTRACT
Elucidation of reinforcing mechanisms for associative learning is an important subject in neuroscience. Based on results of our previous pharmacological studies in crickets, we suggested that octopamine and dopamine mediate reward and punishment signals, respectively, in associative learning. In fruit-flies, however, it was concluded that dopamine mediates both appetitive and aversive reinforcement, which differs from our suggestion in crickets. In our previous studies, the effect of conditioning was tested at 30 min after training or later, due to limitations of our experimental procedures, and thus the possibility that octopamine and dopamine were not needed for initial acquisition of learning was not ruled out. In this study we first established a conditioning procedure to enable us to evaluate acquisition performance in crickets. Crickets extended their maxillary palpi and vigorously swung them when they perceived some odors, and we found that crickets that received pairing of an odor with water reward or sodium chloride punishment exhibited an increase or decrease in percentages of maxillary palpi extension responses to the odor. Using this procedure, we found that octopamine and dopamine receptor antagonists impair acquisition of appetitive and aversive learning, respectively. This finding suggests that neurotransmitters mediating appetitive reinforcement differ in crickets and fruit-flies.

No MeSH data available.


Related in: MedlinePlus

Procedures for differential olfactory conditioning with water reward or sodium chloride punishment. Crickets were subjected to presentation of one odor (paired odor: CS) paired with water (appetitive US) or a high concentration (20%) of sodium chloride solution (aversive US) and another odor (unpaired odor) without pairing with US five or six times each with pseudo-random sequences and with 5-min intervals. Retention was tested at 1 day after training. For pharmacology, 3 μL of saline or saline containing 2 μM epinastine or 200 μM flupentixol was injected into the hemolymph at 20 min before training.
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Figure 1: Procedures for differential olfactory conditioning with water reward or sodium chloride punishment. Crickets were subjected to presentation of one odor (paired odor: CS) paired with water (appetitive US) or a high concentration (20%) of sodium chloride solution (aversive US) and another odor (unpaired odor) without pairing with US five or six times each with pseudo-random sequences and with 5-min intervals. Retention was tested at 1 day after training. For pharmacology, 3 μL of saline or saline containing 2 μM epinastine or 200 μM flupentixol was injected into the hemolymph at 20 min before training.

Mentions: We used differential appetitive or aversive conditioning procedures with water reward or sodium chloride punishment. In differential appetitive conditioning, individual animals received five trials, in which one of the two odors (peppermint and apple odors) was paired with water (unconditioned stimulus, US) and another odor was presented alone without pairing with US with an inter-trial interval (ITI) of 5 min (Figure 1). We refer to the former odor as paired odor (or conditioned stimulus, CS) and the latter odor as unpaired odor. Hypodermic syringes of 1 ml each were used for conditioning. A small filter paper was attached to the needle of the syringe. The syringe was filled with water, and the filter paper was soaked in peppermint or apple essence. For odor presentation, the filter paper was placed within 1 cm of the cricket's head. At 3 s after the onset of odor presentation, a drop of water was given to the mouth of the cricket for 2 s. The presence or absence of an MER was recorded during the first 3 s of odor presentation. In differential aversive conditioning experiment, individual animals received six trials, in which one of the two odors (vanilla and maple odors) was paired with a high concentration (20%) of sodium chloride solution (aversive US) and another odor was presented alone. Crickets exhibited MERs to these odors with high percentages (60–80%) prior to conditioning. The sequence of odor presentations was pseudo-randomized to avoid a possible sequential effect (Figure 1).


Roles of octopamine and dopamine in appetitive and aversive memory acquisition studied in olfactory conditioning of maxillary palpi extension response in crickets.

Matsumoto Y, Matsumoto CS, Wakuda R, Ichihara S, Mizunami M - Front Behav Neurosci (2015)

Procedures for differential olfactory conditioning with water reward or sodium chloride punishment. Crickets were subjected to presentation of one odor (paired odor: CS) paired with water (appetitive US) or a high concentration (20%) of sodium chloride solution (aversive US) and another odor (unpaired odor) without pairing with US five or six times each with pseudo-random sequences and with 5-min intervals. Retention was tested at 1 day after training. For pharmacology, 3 μL of saline or saline containing 2 μM epinastine or 200 μM flupentixol was injected into the hemolymph at 20 min before training.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555048&req=5

Figure 1: Procedures for differential olfactory conditioning with water reward or sodium chloride punishment. Crickets were subjected to presentation of one odor (paired odor: CS) paired with water (appetitive US) or a high concentration (20%) of sodium chloride solution (aversive US) and another odor (unpaired odor) without pairing with US five or six times each with pseudo-random sequences and with 5-min intervals. Retention was tested at 1 day after training. For pharmacology, 3 μL of saline or saline containing 2 μM epinastine or 200 μM flupentixol was injected into the hemolymph at 20 min before training.
Mentions: We used differential appetitive or aversive conditioning procedures with water reward or sodium chloride punishment. In differential appetitive conditioning, individual animals received five trials, in which one of the two odors (peppermint and apple odors) was paired with water (unconditioned stimulus, US) and another odor was presented alone without pairing with US with an inter-trial interval (ITI) of 5 min (Figure 1). We refer to the former odor as paired odor (or conditioned stimulus, CS) and the latter odor as unpaired odor. Hypodermic syringes of 1 ml each were used for conditioning. A small filter paper was attached to the needle of the syringe. The syringe was filled with water, and the filter paper was soaked in peppermint or apple essence. For odor presentation, the filter paper was placed within 1 cm of the cricket's head. At 3 s after the onset of odor presentation, a drop of water was given to the mouth of the cricket for 2 s. The presence or absence of an MER was recorded during the first 3 s of odor presentation. In differential aversive conditioning experiment, individual animals received six trials, in which one of the two odors (vanilla and maple odors) was paired with a high concentration (20%) of sodium chloride solution (aversive US) and another odor was presented alone. Crickets exhibited MERs to these odors with high percentages (60–80%) prior to conditioning. The sequence of odor presentations was pseudo-randomized to avoid a possible sequential effect (Figure 1).

Bottom Line: In fruit-flies, however, it was concluded that dopamine mediates both appetitive and aversive reinforcement, which differs from our suggestion in crickets.Crickets extended their maxillary palpi and vigorously swung them when they perceived some odors, and we found that crickets that received pairing of an odor with water reward or sodium chloride punishment exhibited an increase or decrease in percentages of maxillary palpi extension responses to the odor.Using this procedure, we found that octopamine and dopamine receptor antagonists impair acquisition of appetitive and aversive learning, respectively.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Science, Hokkaido University Sapporo, Japan ; Faculty of Liberal Arts, Tokyo Medical and Dental University Ichikawa, Japan.

ABSTRACT
Elucidation of reinforcing mechanisms for associative learning is an important subject in neuroscience. Based on results of our previous pharmacological studies in crickets, we suggested that octopamine and dopamine mediate reward and punishment signals, respectively, in associative learning. In fruit-flies, however, it was concluded that dopamine mediates both appetitive and aversive reinforcement, which differs from our suggestion in crickets. In our previous studies, the effect of conditioning was tested at 30 min after training or later, due to limitations of our experimental procedures, and thus the possibility that octopamine and dopamine were not needed for initial acquisition of learning was not ruled out. In this study we first established a conditioning procedure to enable us to evaluate acquisition performance in crickets. Crickets extended their maxillary palpi and vigorously swung them when they perceived some odors, and we found that crickets that received pairing of an odor with water reward or sodium chloride punishment exhibited an increase or decrease in percentages of maxillary palpi extension responses to the odor. Using this procedure, we found that octopamine and dopamine receptor antagonists impair acquisition of appetitive and aversive learning, respectively. This finding suggests that neurotransmitters mediating appetitive reinforcement differ in crickets and fruit-flies.

No MeSH data available.


Related in: MedlinePlus