Neural and molecular mechanisms of microcognition in<i>Limax</i>

Watanabe, Satoshi; Kirino, Yutaka; Gelperin, Alan

doi:10.1101/lm920908

Cited by 48 publications

(40 citation statements)

References 180 publications

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“…4C,D). We excluded the PC from the analysis because neurogenesis continuously occurs in the PC even in the adult (Zakharov et al, 1998;Watanabe et al, 2008), and it results in BrdU incorporation into many newborn neurons in the absence of DNA endoreplication (Matsuo and Ito, 2011). Most of the BrdU-positive signals were spatially sporadic and rarely existed in juxtaposed locations (Fig.…”

Section: Dna Synthesis Is Enhanced During the Gain Of Body Weightmentioning

confidence: 99%

DNA Endoreplication in the Brain Neurons during Body Growth of an Adult Slug

Yamagishi¹,

Ito²,

Matsuo³

2011

J. Neurosci.

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Endoreplication is DNA synthesis without cell division. Giant neurons observed in the brains of mollusks are thought to be generated as a result of DNA endoreplication. It has been hypothesized that neuronal size becomes larger in parallel with an increase in body size and that DNA endoreplication is involved in this process to meet the increasing demand for macromolecules in neurons. There is, however, no experimental evidence for this hypothesis to date. In the present study, we investigated the following quantitatively: (1) the size of the brain and each ganglion, (2) the size of identified neurons, (3) the total number of neurons undergoing DNA endoreplication, (4) the total number of the neurons containing a cardioexcitatory peptide, and (5) the gene expression level per neuron, using terrestrial slugs whose body growth was regulated through the amount of food supplied in the laboratory. The body growth was accompanied by increases in the sizes of both neurons and ganglia and triggered more frequent DNA endoreplication events in each ganglion of the growth-promoted slugs, without increasing the total number of neurons. Increase in the neuronal size also involved the increase in the amount of transcripts expressed in a single neuron. This is the first quantitative evidence showing that the DNA endoreplication, neuronal size, and gene expression are increased concomitantly with body growth in adult mollusks.

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Section: Dna Synthesis Is Enhanced During the Gain Of Body Weightmentioning

confidence: 99%

DNA Endoreplication in the Brain Neurons during Body Growth of an Adult Slug

Yamagishi¹,

Ito²,

Matsuo³

2011

J. Neurosci.

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“…The PC exhibits oscillation of local field potentials (LFP) at 0.7 Hz (Gelperin and Tank 1990). It is thus suitable for study of the contribution of oscillation to information processing in a nervous system that features learning, and has been studied extensively (for reviews, see Gelperin 1999Gelperin , 2006Watanabe et al 2008). For example, LFP oscillation is synchronized over the entire PC lobe, with wave propagation from apical to basal parts (Delany et al 1994;Kawahara et al 1997;Kimura et al 1998c).…”

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confidence: 99%

Internal representation and memory formation of odor preference based on oscillatory activities in a terrestrial slug

Sekiguchi¹,

Furudate²,

Kimura³

2010

Learn. Mem.

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The terrestrial slug Limax exhibits a highly developed ability to learn odors with a small nervous system. When a fluorescent dye, Lucifer Yellow (LY), is injected into the slug's body cavity after odor -taste associative conditioning, a group of neurons in the procerebral (PC) lobe, an olfactory center of the slug, is labeled by LY. We examined the relationships between conditioning strategies and LY labeling. The positions of LY-labeled neurons in the PC lobe after appetitive conditioning were more apical than those after aversive conditioning and did not depend on the conditioned odor, suggesting that the biological value of odors affected the position of LY-labeled neural clusters. A simple computational model consisting of two layers of oscillators with electrical synaptic interaction was constructed based on physiological features of the PC lobe, and showed that the oscillatory phase difference between the layers contributed to determination of the positions of LY-labeled neurons, suggesting that phase difference in oscillatory activity plays a role in the association of odors and the preference for them. (Wehr and Laurent 1996); and (6) they play roles in the mechanisms of fine odor discrimination (Stopfer et al. 1997;Teyke and Gelperin 1999).For terrestrial slugs, olfactory information is the most important means of recognizing the external world, and slugs exhibit various types of odor learning (Sahley et al. 1981(Sahley et al. , 1990Hopfield and Gelperin 1989;Suzuki et al. 1994). Slugs have two pairs of tentacles that sense odors via olfactory receptors at their tips. Odor information is transferred to the procerebral (PC) lobe, which is the lateral part of the cerebral ganglion and is specialized for olfactory information processing in terrestrial slugs and snails (Ratte and Chase 1997;Chase 2000;Zaitseva 2000). On the surface of the PC lobe, large numbers of cell bodies of interneurons are arranged and elongate their neuropils toward the inside of the PC lobe, where afferent fibers from the tentacles are projected (Kawahara et al. 1997). The PC exhibits oscillation of local field potentials (LFP) at 0.7 Hz (Gelperin and Tank 1990). It is thus suitable for study of the contribution of oscillation to information processing in a nervous system that features learning, and has been studied extensively (for reviews, see Gelperin 1999Gelperin , 2006Watanabe et al. 2008). For example, LFP oscillation is synchronized over the entire PC lobe, with wave propagation from apical to basal parts (Delany et al. 1994;Kawahara et al. 1997;Kimura et al. 1998c). The application of learned odors changes the frequency of the LFP oscillation (Kimura et al. 1998a;Inoue et al. 2006). In addition, when a fluorescent dye, Lucifer Yellow (LY), is injected into the body cavity after odor learning, some of the PC interneurons incorporate the dye (Kimura et al. 1998b;Gelperin 1999;Ermentrout et al. 2001). Since the incorporation of LY depends on conditioning treatment and the duration between conditioning and LY injection (Kimura...

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“…In the TG, a field potential oscillation has been recorded in Limax, and its frequency is modulated by an exogenous application of several classical neurotransmitters (Ito et al, 2001;Inokuma et al, 2002;Ito et al, 2004). These characteristics are reminiscent of the PC, which is a well-known locus for the storage of olfactory memory (Gelperin, 1999;Watanabe et al, 2008;.…”

Section: Discussionmentioning

confidence: 99%