Early polysynaptic potentiation recorded in the dentate gyrus during an associative learning task

Chaillan, Franck A.; Truchet, Bruno; Roman, François S.; Soumireu-Mourat, Bernard

doi:10.1016/s0306-4522(99)00304-8

Cited by 19 publications

(14 citation statements)

References 42 publications

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“…Our data do not confirm those of Chaillan et al (1999) who reported potentiation of a polysynaptic response in the DG during learning. However, it is important to note that in our study, a recording session began 1 h after a training session; whereas Chaillan et al (1999) recordings were done immediately after the training session.…”

Section: Mouly and Gervaiscontrasting

confidence: 57%

“…However, it is important to note that in our study, a recording session began 1 h after a training session; whereas Chaillan et al (1999) recordings were done immediately after the training session. In the latter study, the observed potentiation was maximal just after each training session and decreased to a lower level when measured 24 h later.…”

Section: Mouly and Gervaismentioning

confidence: 99%

“…Second, in a previous work using voltagesensitive dye to map piriform cortex activity, we showed that olfactory learning greatly enhanced the occurrence of a late component posterior piriform cortex (Litaudon et al 1997). Finally, Chaillan et al (1999) reported that olfactory associative learning was accompanied by potentiation of a late polysynaptic response recorded in the DG in response to electrical stimulation of the lateral olfactory tract. Taken together these data suggest that potentiation of polysynaptic components could be induced in parallel at several levels of the olfactory pathways during learning.…”

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Polysynaptic Potentiation at Different Levels of Rat Olfactory Pathways Following Learning

Mouly

Gervais²

2002

Learn. Mem.

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This study was aimed at investigating the consequences of learning on late polysynaptic components of evoked field potential signals recorded in parallel at different levels of the olfactory pathways. For this, evoked field potentials induced by electrical stimulation of the olfactory bulb were recorded simultaneously in the anterior piriform cortex, the posterior piriform cortex, the lateral entorhinal cortex, and the dentate gyrus. The different parameters of late components were measured in each site before and after completion of associative learning in anesthetized rats. In the learning task, rats were trained to associate electrical stimulation of one olfactory bulb electrode with the delivery of sucrose (positive reward) and stimulation of a second olfactory bulb electrode with the delivery of quinine (negative reward). In this way, stimulation of the same olfactory bulb electrodes used for inducing field potentials served as a discriminative cue in the learning paradigm. The data confirmed previous observation that learning was associated with a lowering in late-component-1 intensity of induction in the posterior piriform cortex. The use of simultaneous recording allowed us to further specify the consequences of learning on late-component distribution in the studied network. Indeed the data showed that whereas before learning, late component 1 was rather uniformly distributed among the recorded sites; following learning, its expression was facilitated preferentially in the posterior piriform cortex and lateral entorhinal cortex. Furthermore, learning was accompanied by the emergence of a new late component (late component 2), which occurred simultaneously in the four recording sites. The possible involvement of potentiation of polysynaptic components in recognition and/or consolidation processes will be discussed

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Section: Mouly and Gervaiscontrasting

confidence: 57%

Section: Mouly and Gervaismentioning

confidence: 99%

mentioning

confidence: 99%

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Polysynaptic Potentiation at Different Levels of Rat Olfactory Pathways Following Learning

Mouly

Gervais²

2002

Learn. Mem.

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“…In contrast, polysynaptic responses were unchanged prior to and immediately following session 3. Furthermore, this polysynaptic potentiation was correlated to learning (Chaillan et al 1999). The decrease in Kv1.1 mRNA observed in the current study following session 2 and not session 3 may contribute to the dynamic activation of the hippocampal circuitry during associative information processing.…”

Section: Discussionmentioning

confidence: 99%

“…In the examination of olfactory pathways, an analysis was performed on regions believed to be necessary for the learning and memory of olfactory associative tasks (olfactory bulb, Ammon's horn, and dentate gyrus) (Chaillan et al 1999;Truchet et al 2002), as well as in the three animal groups (naive group, pseudoconditioned group, and conditioned group). The Kv1.1 mRNA level was analyzed in the olfactory bulb and in three structures of the dorsal and ventral hippocampus (dentate gyrus, CA3 and CA1) of rats sacrificed at three stages of learning, i.e., 1 h after session 2, 4 h after the session 2, and 1 h after session 3.…”

Section: Comparison Of Kv11 Mrna Levels Between the Groupsmentioning

confidence: 99%

Transient hippocampal down-regulation of Kv1.1 subunit mRNA during associative learning in rats

Kourrich¹,

Manrique

Salin

et al. 2005

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Voltage-gated potassium channels (Kv) are critically involved in learning and memory processes. It is not known, however, whether the expression of the Kv1.1 subunit, constituting Kv1 channels, can be specifically regulated in brain areas important for learning and memory processing. Radioactive in situ hybridization was used to evaluate the content of Kv1.1 ␣-subunit mRNA in the olfactory bulb, ventral, and dorsal hippocampus at different stages of an odor-discrimination associative task in rats. Naive, conditioned, and pseudoconditioned animals were sacrificed at different times either prior to a two-odor significance learning or after odor discrimination was established. Important decreases of Kv1.1 mRNA levels were transiently observed in the ventral hippocampus before successful learning when compared with the pseudoconditioned group. Moreover, temporal group analysis showed significant labeling alterations in the hippocampus of conditioned and pseudoconditioned groups throughout the training. Finally, Kv1.1 mRNA levels in the hippocampus were positively correlated with odor-reward association learning in rats that were beginning to discriminate between odors. These findings indicate that the Kv1.1 subunit is transiently down-regulated in the early stages of learning and suggest that Kv1 channel expression regulation is critical for the modification of neuronal substrates underlying new information acquisition.

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Learning and memory of cue–reward association meaning by modifications of synaptic efficacy in dentate gyrus and piriform cortex

Truchet¹,

Chaillan²,

Soumireu-Mourat³

et al. 2002

Hippocampus

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ABSTRACT:This article begins with a review of recent experiments investigating the synaptic efficacy changes occurring in rat dentate gyrus and piriform cortex during an associative olfactory task. In all these experiments, animals were trained to discriminate among an artificial cue, a patterned electrical stimulation distributed to the lateral olfactory tract associated with a water reward, and a natural odor associated with a flash of light. Monosynaptic field potential responses evoked by single electrical stimuli to the lateral olfactory tract were recorded in the ipsilateral piriform cortex before and just after each training session. Monosynaptic field and polysynaptic field potentials evoked by single electrical stimuli applied respectively to the lateral perforant pathway and lateral olfactory tract were also recorded in ipsilateral dentate gyrus. The results showed an increase in synaptic efficacy subsequent to the first training session in the dentate gyrus network when compared with piriform cortex at the later stage of the learning. The early increase of monosynaptic response in the dentate gyrus was observed immediately after the first learning session but disappeared 24 h later. Inversely, a synaptic depression developed across sessions, becoming significant at the onset of the last (fifth) session. The polysynaptic potential recorded in this structure increased substantially when rats began to discriminate the learning cues, usually after the second or third learning session. Then, from the third to the fifth session, an LTP like-phenomenon appeared in piriform cortex when rats perfectly mastered the associations. Experiments using high-frequency stimulation to prevent changes in gyrus dentatus indicated that the onset of the observed depression was necessary for the learning of the olfactory associations. The fact that hippocampal and cortical neuronal networks exhibited different timing in synaptic efficacy changes could physiologically explain learning and memory processes. Hippocampus 2002;12: 600-608.

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Early polysynaptic potentiation recorded in the dentate gyrus during an associative learning task

Abstract: potentiation recorded in the dentate gyrus during an associative learning task. Neuroscience, Elsevier

Cited by 19 publications

References 42 publications

Polysynaptic Potentiation at Different Levels of Rat Olfactory Pathways Following Learning

Polysynaptic Potentiation at Different Levels of Rat Olfactory Pathways Following Learning

Transient hippocampal down-regulation of Kv1.1 subunit mRNA during associative learning in rats

Learning and memory of cue–reward association meaning by modifications of synaptic efficacy in dentate gyrus and piriform cortex

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