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Roles of aminergic neurons in formation and recall of associative memory in crickets.

Mizunami M, Matsumoto Y - Front Behav Neurosci (2010)

Bottom Line: The former is called stimulus-response (S-R) connection and the latter is called stimulus-stimulus (S-S) connection by theorists studying classical conditioning in vertebrates.Results of our studies using a second-order conditioning procedure supported our model.We propose that insect classical conditioning involves the formation of S-S connection and its activation for memory recall, which are often called cognitive processes.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Life Science, Hokkaido University, Sapporo, Japan. mizunami@sci.hokudai.ac.jp

ABSTRACT
We review recent progress in the study of roles of octopaminergic (OA-ergic) and dopaminergic (DA-ergic) signaling in insect classical conditioning, focusing on our studies on crickets. Studies on olfactory learning in honey bees and fruit-flies have suggested that OA-ergic and DA-ergic neurons convey reinforcing signals of appetitive unconditioned stimulus (US) and aversive US, respectively. Our work suggested that this is applicable to olfactory, visual pattern, and color learning in crickets, indicating that this feature is ubiquitous in learning of various sensory stimuli. We also showed that aversive memory decayed much faster than did appetitive memory, and we proposed that this feature is common in insects and humans. Our study also suggested that activation of OA- or DA-ergic neurons is needed for appetitive or aversive memory recall, respectively. To account for this finding, we proposed a model in which it is assumed that two types of synaptic connections are strengthened by conditioning and are activated during memory recall, one type being connections from neurons representing conditioned stimulus (CS) to neurons inducing conditioned response and the other being connections from neurons representing CS to OA- or DA-ergic neurons representing appetitive or aversive US, respectively. The former is called stimulus-response (S-R) connection and the latter is called stimulus-stimulus (S-S) connection by theorists studying classical conditioning in vertebrates. Results of our studies using a second-order conditioning procedure supported our model. We propose that insect classical conditioning involves the formation of S-S connection and its activation for memory recall, which are often called cognitive processes.

No MeSH data available.


Related in: MedlinePlus

Appetitive (A) and aversive (B) second-order conditioning. Two groups of animals were each subjected to appetitive (A) or aversive (B) second-order conditioning trials (P/P groups). Four control groups were each subjected to unpaired presentations in the first (UP/P groups) or second (P/UP groups) stage in appetitive (A) or aversive (B) second-order conditioning. Animals received 4 first-stage trials and then 4 second-stage trials for appetitive second-order conditioning and 6 first-stage trials and then 4 second-stage trials for aversive second-order conditioning. Preference indexes for the CS2 (in the case of appetitive second-order conditioning) or control pattern (in the case of aversive second-order conditioning) before (white bars) and after (black bars) conditioning are shown with mean + SEM. The results of statistical comparison before and after conditioning (WCX test) and between experimental and saline-injected control groups (M–W test) are shown as asterisks (p < 0.05; p < 0.01; p < 0.001, NS p > 0.05). Modified from Mizunami et al. (2009).
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Figure 8: Appetitive (A) and aversive (B) second-order conditioning. Two groups of animals were each subjected to appetitive (A) or aversive (B) second-order conditioning trials (P/P groups). Four control groups were each subjected to unpaired presentations in the first (UP/P groups) or second (P/UP groups) stage in appetitive (A) or aversive (B) second-order conditioning. Animals received 4 first-stage trials and then 4 second-stage trials for appetitive second-order conditioning and 6 first-stage trials and then 4 second-stage trials for aversive second-order conditioning. Preference indexes for the CS2 (in the case of appetitive second-order conditioning) or control pattern (in the case of aversive second-order conditioning) before (white bars) and after (black bars) conditioning are shown with mean + SEM. The results of statistical comparison before and after conditioning (WCX test) and between experimental and saline-injected control groups (M–W test) are shown as asterisks (p < 0.05; p < 0.01; p < 0.001, NS p > 0.05). Modified from Mizunami et al. (2009).

Mentions: We first studied whether second-order conditioning can be achieved in crickets (Figure 8; Mizunami et al., 2009). We used an olfactory stimulus as CS1 and a visual pattern as CS2. For appetitive or aversive conditioning, an odor (CS1) was paired with water or sodium chloride solution, respectively, and then a visual pattern (CS2) was paired with an odor (CS1). A group of animals that was subjected to appetitive second-order conditioning trials exhibited significantly increased preference for the CS2 (Figure 8A). In contrast, control groups that were each subjected to unpaired presentations of stimuli at the first or second conditioning stage exhibited no significantly increased preference for the CS2 (Figure 8A), thus indicating that the increased preference for the CS2 in the experimental group is truly the result of second-order conditioning. Similarly, we showed that second-order aversive conditioning could be achieved (Figure 8B).


Roles of aminergic neurons in formation and recall of associative memory in crickets.

Mizunami M, Matsumoto Y - Front Behav Neurosci (2010)

Appetitive (A) and aversive (B) second-order conditioning. Two groups of animals were each subjected to appetitive (A) or aversive (B) second-order conditioning trials (P/P groups). Four control groups were each subjected to unpaired presentations in the first (UP/P groups) or second (P/UP groups) stage in appetitive (A) or aversive (B) second-order conditioning. Animals received 4 first-stage trials and then 4 second-stage trials for appetitive second-order conditioning and 6 first-stage trials and then 4 second-stage trials for aversive second-order conditioning. Preference indexes for the CS2 (in the case of appetitive second-order conditioning) or control pattern (in the case of aversive second-order conditioning) before (white bars) and after (black bars) conditioning are shown with mean + SEM. The results of statistical comparison before and after conditioning (WCX test) and between experimental and saline-injected control groups (M–W test) are shown as asterisks (p < 0.05; p < 0.01; p < 0.001, NS p > 0.05). Modified from Mizunami et al. (2009).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC2991128&req=5

Figure 8: Appetitive (A) and aversive (B) second-order conditioning. Two groups of animals were each subjected to appetitive (A) or aversive (B) second-order conditioning trials (P/P groups). Four control groups were each subjected to unpaired presentations in the first (UP/P groups) or second (P/UP groups) stage in appetitive (A) or aversive (B) second-order conditioning. Animals received 4 first-stage trials and then 4 second-stage trials for appetitive second-order conditioning and 6 first-stage trials and then 4 second-stage trials for aversive second-order conditioning. Preference indexes for the CS2 (in the case of appetitive second-order conditioning) or control pattern (in the case of aversive second-order conditioning) before (white bars) and after (black bars) conditioning are shown with mean + SEM. The results of statistical comparison before and after conditioning (WCX test) and between experimental and saline-injected control groups (M–W test) are shown as asterisks (p < 0.05; p < 0.01; p < 0.001, NS p > 0.05). Modified from Mizunami et al. (2009).
Mentions: We first studied whether second-order conditioning can be achieved in crickets (Figure 8; Mizunami et al., 2009). We used an olfactory stimulus as CS1 and a visual pattern as CS2. For appetitive or aversive conditioning, an odor (CS1) was paired with water or sodium chloride solution, respectively, and then a visual pattern (CS2) was paired with an odor (CS1). A group of animals that was subjected to appetitive second-order conditioning trials exhibited significantly increased preference for the CS2 (Figure 8A). In contrast, control groups that were each subjected to unpaired presentations of stimuli at the first or second conditioning stage exhibited no significantly increased preference for the CS2 (Figure 8A), thus indicating that the increased preference for the CS2 in the experimental group is truly the result of second-order conditioning. Similarly, we showed that second-order aversive conditioning could be achieved (Figure 8B).

Bottom Line: The former is called stimulus-response (S-R) connection and the latter is called stimulus-stimulus (S-S) connection by theorists studying classical conditioning in vertebrates.Results of our studies using a second-order conditioning procedure supported our model.We propose that insect classical conditioning involves the formation of S-S connection and its activation for memory recall, which are often called cognitive processes.

View Article: PubMed Central - PubMed

Affiliation: Graduate School of Life Science, Hokkaido University, Sapporo, Japan. mizunami@sci.hokudai.ac.jp

ABSTRACT
We review recent progress in the study of roles of octopaminergic (OA-ergic) and dopaminergic (DA-ergic) signaling in insect classical conditioning, focusing on our studies on crickets. Studies on olfactory learning in honey bees and fruit-flies have suggested that OA-ergic and DA-ergic neurons convey reinforcing signals of appetitive unconditioned stimulus (US) and aversive US, respectively. Our work suggested that this is applicable to olfactory, visual pattern, and color learning in crickets, indicating that this feature is ubiquitous in learning of various sensory stimuli. We also showed that aversive memory decayed much faster than did appetitive memory, and we proposed that this feature is common in insects and humans. Our study also suggested that activation of OA- or DA-ergic neurons is needed for appetitive or aversive memory recall, respectively. To account for this finding, we proposed a model in which it is assumed that two types of synaptic connections are strengthened by conditioning and are activated during memory recall, one type being connections from neurons representing conditioned stimulus (CS) to neurons inducing conditioned response and the other being connections from neurons representing CS to OA- or DA-ergic neurons representing appetitive or aversive US, respectively. The former is called stimulus-response (S-R) connection and the latter is called stimulus-stimulus (S-S) connection by theorists studying classical conditioning in vertebrates. Results of our studies using a second-order conditioning procedure supported our model. We propose that insect classical conditioning involves the formation of S-S connection and its activation for memory recall, which are often called cognitive processes.

No MeSH data available.


Related in: MedlinePlus