Publications by authors named "Cécile Bellanger"

17 Publications

  • Page 1 of 1

Alteration of predatory behaviour and growth in juvenile cuttlefish by fluoxetine and venlafaxine.

Chemosphere 2021 Aug 17;277:130169. Epub 2021 Mar 17.

NORMANDIE UNIV, UNICAEN, UNIV RENNES, CNRS, EthoS (Éthologie animale et humaine) - UMR 6552, F-14000, Caen, France. Electronic address:

Antidepressants in coastal waters may affect ontogeny of predatory behaviour in cuttlefish, which may, as a result, affect growth of newly-hatched cuttlefish. We investigated the effects of two of the most prescribed antidepressants, fluoxetine (FLX) and venlafaxine (VEN) in environmentally realistic concentrations on the predatory behaviour of hatchlings of Sepia officinalis. Newly-hatched cuttlefish were exposed from 1 h (i.e., day 1) to 5 days after hatching to either FLX alone (5 ng·L) or combined with VEN (2.5 ng·L or 5 ng·L each) to simulate an environmentally realistic exposure scenario. Their predatory behaviour was analysed through several parameters: prey detection, feeding motivation and success in catching the prey. All parameters improved in control animals over the first five days. The combination of FLX and VEN at 5 ng·L each altered the predatory behaviour of the hatchlings by increasing the latency before attacking the prey, i.e., reducing feeding motivation, as well as by reducing the number of successful attacks. The changes in predatory behaviour tended to reduce food intake and affected growth significantly at 28 days post-hatching. Exposures to either FLX at 5 ng·L or FLX and VEN in mixture at 2.5 ng·L each tended to produce similar effects, even though they were not statistically significant. It is likely that the antidepressants affect maturation of the predatory behaviour and/or learning processes associated with the development of this behaviour. The slightest delay in maturation processes may have detrimental consequences for growth and population fitness.
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http://dx.doi.org/10.1016/j.chemosphere.2021.130169DOI Listing
August 2021

Effects of environmental antidepressants on colour change and locomotor behaviour in juvenile shore crabs, Carcinus maenas.

Aquat Toxicol 2021 May 12;234:105808. Epub 2021 Mar 12.

NORMANDIE UNIV, UNILEHAVRE, FR CNRS 3730 SCALE, UMR-I02, Environmental Stress and Biomonitoring of Aquatic Environments (SEBIO), 76600 LE HAVRE, France. Electronic address:

Juvenile crabs of Carcinus maenas thrive in coastal waters reputed to be the receptacle of continental pollution. Amongst the many pollutants encountered, antidepressants, such as fluoxetine (FLX) and venlafaxine (VEN), often detected at the ng•L range, are particularly worrying because of their action on the levels of monoamines, such as serotonin, noradrenaline and dopamine. In crustaceans, those monoamines are involved in colour change through their action on neuropeptide hormones. In addition, they are known to have a role in different behaviours, such as locomotion. Both colour change and locomotion are strategies used by juvenile crabs to hide and escape from predators. To investigate if the presence of antidepressants may alter behaviours of ecological importance, juvenile crabs were exposed to environmentally realistic concentrations of either 5 ng•L of FLX alone or in combination with VEN at 5 ng•L. The ability to change colour depending on the environment and the locomotor activity of juvenile crabs were monitored weekly over 25 days. Animals exposed to antidepressants displayed a different pattern of colour change than the controls, especially those exposed to the combination of FLX and VEN at 5 ng•L each, and were less efficient to adapt to their environment, i.e., they were not as pale and not as dark as controls or crabs exposed to FLX at 5 ng•L. Moreover, juvenile crabs exposed to the combination of antidepressants exhibited an enhanced locomotor activity throughout the exposure period with a higher velocity and distance moved as well as more time spend moving. The alteration of cryptic behaviours, such as colour change and locomotion by antidepressants persistently present in marine environment at low concentrations may have an impact on the survival of juvenile of C. maenas on the long term.
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http://dx.doi.org/10.1016/j.aquatox.2021.105808DOI Listing
May 2021

Hidden in the sand: Alteration of burying behaviour in shore crabs and cuttlefish by antidepressant exposure.

Ecotoxicol Environ Saf 2019 Dec 11;186:109738. Epub 2019 Oct 11.

Normandie Univ, UNILEHAVRE, FR CNRS 3730 SCALE, UMR-I02, Environmental Stress and Biomonitoring of Aquatic Environments (SEBIO), 76600, Le Havre, France. Electronic address:

Pharmaceuticals such as antidepressants are constantly released into the aquatic environment. Consequently, fluoxetine (FLX) and venlafaxine (VEN), the active molecules of Prozac© and Effexor©, are detected up to several µg.L in freshwater and marine coastal waters. Both compounds act on the serotoninergic system, which may result in behavioural impairment, especially in juvenile animals presumed to be more susceptible to low concentrations than adults. The objective of this study was to determine whether environmental concentrations of FLX alone or combined with VEN modulate innate burying behaviour in two juvenile marine invertebrates, i.e. Sepia officinalis and Carcinus maenas. Juvenile cuttlefish were exposed from hatching to 30 days post-hatching to either FLX alone (i.e. 5 ng.L) or in mixture with VEN (i.e. either 2.5 ng.L or 5 ng.L of each antidepressant). Juvenile crabs (<2 cm carapace width) were exposed for a period of 22 days to 5 ng.L of FLX and a mixture of 5 ng.L of FLX and VEN each. Several parameters of sand-digging behaviour were analysed weekly in both species. The occurrence of sand-digging behaviour decreased in cuttlefish exposed to a mixture of FLX and VEN at the lowest concentration (2.5 ng.L each). Because sand-digging behaviour improved in controls, this decrease was likely to be related to a modification of maturation and/or learning processes. At the mixture of 5 ng.L VEN and FLX each, a better body covering was observed in juvenile crabs. In both species, innate behaviour was modified under exposure to mixtures of FLX and VEN at environmentally realistic concentrations. These alterations were observed at an early developmental stage, when animals are particularly prone to predation. Hence, modified maturation of behavioural traits and, putatively, learning processes by exposure to pseudo-persistent antidepressants may affect the survival of these two species in the long term.
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http://dx.doi.org/10.1016/j.ecoenv.2019.109738DOI Listing
December 2019

Visual asymmetries in cuttlefish during brightness matching for camouflage.

Curr Biol 2018 09;28(17):R925-R926

Normandie Univ., UNICAEN, Univ Rennes, CNRS, UMR EthoS 6552, Caen, France.

Many animals use camouflage to avoid detection by predators. Camouflage can take several forms, one of which includes brightness matching, a form of crypsis, which occurs when an individual resembles the brightness of their surrounding habitat. Most animals have evolved skin patterning that is fixed and specific to their environment, typically limiting their camouflage abilities to a particular habitat [1]. By contrast, crypsis in cuttlefish is dynamic because they can change their body patterns rapidly (270-730 milliseconds) in response to the visual environment through neural control of pigmented organs known as chromatophores [2,3]. Cuttlefish respond to conflicting visual cues, that is, to different visual information on their left and right sides, with mixed body patterns [4]. This response may be modulated by perceptual asymmetries in visual processing, since cuttlefish exhibit biases when processing visual information, termed visual lateralization [5]. Visual lateralization occurs when information in one visual field is prioritized over the other visual field during a specific behavior, but this phenomenon and its potential effect on camouflage behavior have never before been investigated. We report here that juvenile cuttlefish have a right eye preference for brightness matching, as the substrate perceived in their right visual field was prioritized.
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http://dx.doi.org/10.1016/j.cub.2018.07.019DOI Listing
September 2018

Maternal and Embryonic Stress Influence Offspring Behavior in the Cuttlefish .

Front Physiol 2017 1;8:981. Epub 2017 Dec 1.

Normandie Univ., UNICAEN, Rennes 1 Univ., UR1, CNRS, UMR 6552 ETHOS, Caen, France.

Stress experienced during prenatal development-either applied to reproducing females (maternal stress), directly to developing offspring (embryonic stress) or in combination-is associated with a range of post-natal behavioral effects in numerous organisms. We conducted an experiment to discern if maternal and embryonic stressors affect the behavior of hatchlings of the cuttlefish , a species with features that allow for the examination of these stress types in isolation. Separating the impact of stress transmitted through the mother vs. stress experienced by the embryo itself will help clarify the behavioral findings in viviparous species for which it is impossible to disentangle these effects. We also compared the effect of a naturally-occurring (predator cue) and an "artificial" (bright, randomly-occurring LED light) embryonic stressor. This allowed us to test the hypothesis that a threat commonly faced by a species (natural threat) would be met with a genetically-programmed and adaptive response while a novel one would confound innate defense mechanisms and lead to maladaptive effects. We found that the maternal stressor was associated with significant differences in body patterning and activity patterns. By contrast, embryonic exposure to stressors increased the proportion of individuals that pursued prey. From these results, it appears that in cuttlefish, maternal and embryonic stressors affect different post-natal behavior in offspring. In addition, the effect of the artificial stressor suggests that organisms can sometimes react adaptively to a stressor even if it is not one that has been encountered during the evolutionary history of the species.
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http://dx.doi.org/10.3389/fphys.2017.00981DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5717421PMC
December 2017

The antidepressant venlafaxine may act as a neurodevelopmental toxicant in cuttlefish (Sepia officinalis).

Neurotoxicology 2016 07 6;55:142-153. Epub 2016 Jun 6.

Normandie Université, CS F-14032 Caen, France; GMPc (Groupe Mémoire et Plasticité comportementale), EA 4259, Campus Horowitz, Université de Caen Normandie, Esplanade de la Paix, CS F-14032 Caen cedex, France. Electronic address:

The Serotonin/Norepinephrine Reuptake Inhibitor (SNRI) antidepressant venlafaxine (VEN, Effexor(®)) has become one of the most common antidepressants detected in North American and European streams. Mammalian research has established that VEN exposure is associated with a range of structural, neurochemical, and functional alterations of the brain in adults and newborns. However, the neurodevelopmental effects of VEN on non-target organisms have never been investigated. The aim of our research was to decrease this gap in knowledge by characterizing the effects of VEN exposure on a cephalopod mollusk, the common cuttlefish Sepia officinalis. This species inhabits VEN-contaminated waters and possesses an unusually sophisticated brain. These characteristics render it a unique invertebrate species for studying the neurodevelopmental effects of VEN. Cuttlefish were exposed to environmentally-relevant concentrations of VEN (Measured concentrations ≈5 and 100ngL(-)(1)) or to filtered natural seawater (control) in a closed-loop system with regular water changes during the first 20days after hatching. We evaluated brain maturation as well as neurochemical changes and behavioral performances during this critical period of development. Our results show that both VEN-exposed groups exhibited a decrease in norepinephrine levels, along with a reduction in the relative number of glutamate NMDA-like receptors binding sites in the group exposed to 5ngL(-1) of VEN after 20days of exposure. Brain regional changes in cellular proliferation were observed in VEN-exposed groups in the vertical lobe (i.e. a key structure involved in cognitive processes) and in the optic lobes (i.e. main visual processing centers) in the absence of significant change in their volume. Along with these neurodevelopmental changes, 20days of exposure to 100ngL(-1) of VEN was associated with a decrease in camouflage ability. Overall, our study suggests that VEN is a neurodevelopmental toxicant in non-target aquatic organisms at environmentally-relevant concentrations.
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http://dx.doi.org/10.1016/j.neuro.2016.05.023DOI Listing
July 2016

An HPLC-ECD method for monoamines and metabolites quantification in cuttlefish (cephalopod) brain tissue.

Biomed Chromatogr 2016 Aug 12;30(8):1175-83. Epub 2016 Jan 12.

Normandie Université, CS F-14032 Caen, France.

The cuttlefish belongs to the mollusk class Cephalopoda, considered as the most advanced marine invertebrates and thus widely used as models to study the biology of complex behaviors and cognition, as well as their related neurochemical mechanisms. Surprisingly, methods to quantify the biogenic monoamines and their metabolites in cuttlefish brain remain sparse and measure a limited number of analytes. This work aims to validate an HPLC-ECD method for the simultaneous quantification of dopamine, serotonin, norepinephrine and their main metabolites in cuttlefish brain. In comparison and in order to develop a method suitable to answer both ecological and biomedical questions, the validation was also carried out on a phylogenetically remote species: mouse (mammals). The method was shown to be accurate, precise, selective, repeatable and sensitive over a wide range of concentrations for 5-hydroxyindole-3-acetic acid, serotonin, dopamine, 3,4-dihydroxyphenylacetic acid and norepinephrine in the both extracts of cuttlefish and mouse brain, though with low precision and recovery for 4-hydroxy-3-methoxyphenylethylene glycol. Homovanillic acid, accurately studied in rodents, was not detectable in the brain of cuttlefish. Overall, we described here the first fully validated HPLC method for the routine measurement of both monoamines and metabolites in cuttlefish brain. Copyright © 2016 John Wiley & Sons, Ltd.
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http://dx.doi.org/10.1002/bmc.3663DOI Listing
August 2016

Pre-hatching fluoxetine-induced neurochemical, neurodevelopmental, and immunological changes in newly hatched cuttlefish.

Environ Sci Pollut Res Int 2016 Mar 14;23(6):5030-45. Epub 2015 May 14.

Normandie Université, CS F-14032, Caen, France.

Embryonic and early postembryonic development of the cuttlefish Sepia officinalis (a cephalopod mollusk) occurs in coastal waters, an environment subject to considerable pressure from xenobiotic pollutants such as pharmaceutical residues. Given the role of serotonin in brain development and its interaction with neurodevelopmental functions, this study focused on fluoxetine (FLX), a selective serotonin reuptake inhibitor (SSRI, antidepressant). The goal was to determine the effects of subchronic waterborne FLX exposure (1 and 10 μg L(-1)) during the last 15 days of embryonic development on neurochemical, neurodevelopmental, behavioral, and immunological endpoints at hatching. Our results showed for the first time that organic contaminants, such as FLX, could pass through the eggshell during embryonic development, leading to a substantial accumulation of this molecule in hatchlings. We also found that FLX embryonic exposure (1 and 10 μg L(-1)) (1) modulated dopaminergic but not serotonergic neurotransmission, (2) decreased cell proliferation in key brain structures for cognitive and visual processing, (3) did not induce a conspicuous change in camouflage quality, and (4) decreased lysozyme activity. In the long term, these alterations observed during a critical period of development may impair complex behaviors of the juvenile cuttlefish and thus lead to a decrease in their survival. Finally, we suggest a different mode of action by FLX between vertebrate and non-vertebrate species and raise questions regarding the vulnerability of early life stages of cuttlefish to the pharmaceutical contamination found in coastal waters.
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http://dx.doi.org/10.1007/s11356-015-4591-7DOI Listing
March 2016

Cryptic and biochemical responses of young cuttlefish Sepia officinalis exposed to environmentally relevant concentrations of fluoxetine.

Aquat Toxicol 2014 Jun 3;151:36-45. Epub 2014 Jan 3.

Université de Caen Basse-Normandie, France; Groupe Mémoire et Plasticité comportementale, EA 4259, F-14032 Caen cedex, France. Electronic address:

Antidepressants released in the environment have the potential to generate neural disrupting effects in non-target organisms, yet their putative effects on behaviors have never been studied in cephalopod molluscs. This study assessed the impact of the antidepressant fluoxetine (FLX) on the efficiency of cryptic behaviors (body patterns on uniform, checkerboard and sandy substrates), locomotor activity, and brain chemistry in young cuttlefish exposed to environmental concentrations (1 and 100ngL(-1) of FLX) during the perinatal period. Behavioral responses of cuttlefish were monitored at hatching and two weeks later, and brain monoamine contents were quantified at one month of age. FLX significantly altered the camouflage efficiencies on uniform and sandy backgrounds only at the lowest concentration, but not at 100ngL(-1). Hatchlings exposed to 1ngL(-1) of FLX exhibited a duration exposure-dependent decrease in the uniform camouflage. They also showed a significant increase of the frequency of sand digging behaviors which might make them highly visible to predators in nature. When tested again two weeks later, cuttlefish seemed to have recovered and no more behavioral alterations were observed showing a transitory effect of the antidepressant. FLX did not affect the levels of serotonin, norepinephrine and their metabolites; however, it seemed to influence dopaminergic activity between the two FLX-exposed groups. The results show for the time that environmentally realistic concentrations of a single SSRI significantly impair the cryptic performances of newly hatched cuttlefish, and may ultimately reduce their chance for survival.
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http://dx.doi.org/10.1016/j.aquatox.2013.12.026DOI Listing
June 2014

Effects of perinatal exposure to waterborne fluoxetine on memory processing in the cuttlefish Sepia officinalis.

Aquat Toxicol 2013 May 16;132-133:84-91. Epub 2013 Feb 16.

Université de Caen Basse-Normandie, Groupe Mémoire et Plasticité comportementale, EA 4259, 14032 Caen cedex, France.

Recent ecotoxicological studies highlight the increasing presence of pharmaceuticals discharged in the aquatic environment. Amongst them is the antidepressant fluoxetine (FLX), a selective serotonin reuptake inhibitor, primarily indicated for treatment of depression. The effect of chronic exposure to FLX on memory processing in 1-month-old cuttlefish Sepia officinalis was evaluated. Three groups of new-borns were reared in different conditions: one control group (no FLX) and two groups exposed to environmental concentrations of FLX (1 and 100ng/L) from 15 days pre-hatching to 1 month post-hatching. Acquisition and retention performances were assessed using the 'prawn-in-the-tube' procedure. Perinatal exposure to fluoxetine led to significant changes in memory processing of the animals. The lowest observed effect concentration of this antidepressant on learning and retention was 1ng/L which is under the range of environmental contamination. Cuttlefish exposed at low FLX concentration had impaired acquisition capabilities and animals exposed at high FLX concentration displayed a deficit of memory retention compared to the control group that had nonimpaired initial acquisition and retention performances. The results subsequently suggested that FLX-induced changes in cognitive capacities could potentially lead to inappropriate predatory behaviors in the natural environment. The study provides the basis for future studies on how pharmaceutical contaminants disrupt cognition in ecologically and economically relevant marine invertebrates.
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http://dx.doi.org/10.1016/j.aquatox.2013.02.004DOI Listing
May 2013

Feel, smell and see in an egg: emergence of perception and learning in an immature invertebrate, the cuttlefish embryo.

J Exp Biol 2012 Dec;215(Pt 23):4125-30

Equipe d'Ethologie et de Psychobiologie Sensorielle, Centre des Sciences du Goût et de l'Alimentation, UMR 6265 CNRS/Université de Bourgogne/INRA, F-21000 Dijon, France.

It is now well established that prenatal sensory experience affects development itself and has long-term consequences in terms of postnatal behavior. This study focused on the functionality of the sensory system in cuttlefish in ovo. Embryos of stage 23, 25 and 30 received a tactile, chemical or visual stimulus. An increase of mantle contraction rhythm was taken to indicate a behavioral response to the stimulus. We clearly demonstrated that tactile and chemical systems are functional from stage 23, whereas the visual system is functional only from stage 25. At stage 25 and 30, embryos were also exposed to a repeated light stimulus. Stage 30 embryos were capable of habituation, showing a progressive decrease in contractions across stimulations. This process was not due to fatigue as we observed response recovery after a dishabituation tactile stimulus. This study is the first to show that cuttlefish embryos behaviorally respond to stimuli of different modalities and that the visual system is the last to become functional during embryonic development, as in vertebrate embryos. It also provides new evidence that the memory system develops in ovo in cuttlefish.
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http://dx.doi.org/10.1242/jeb.078295DOI Listing
December 2012

Cerebral correlates of visual lateralization in Sepia.

Behav Brain Res 2012 Sep 4;234(1):20-5. Epub 2012 Jun 4.

Université de Caen Basse-Normandie, Groupe Mémoire et Plasticité comportementale, F-14032 Caen cedex, France.

The common cuttlefish, Sepia officinalis (cephalopod mollusc) has recently become a relevant model for studying the setting-up of brain asymmetry among invertebrates. As the animals age from 3 to 30 days post hatching, they progressively develop a left-turning bias resulting from an eye-use preference. The aim of this study is to investigate whether anatomical (vertical, peduncle, inferior buccal, and optic lobes) or neurochemical (monoamines in optic lobes) brain asymmetries are present in the cuttlefish brain at 3 or at 30 post hatching days; and whether these correlate with side-turning preferences. We here find brain and behavioral asymmetry only at 30 post hatching days. Cuttlefish displayed a significant population bias towards a larger right peduncle lobe, and higher monoamine concentration in the left optic lobe (i.e. serotonin, dopamine and noradrenaline). None of these brain asymmetries were correlated to the studied side-turning bias. However, we found individual variation in the magnitude of the vertical and optic lobes asymmetry. A striking correlation was found with the behavioral results: the larger the right optic lobe and the right part of the vertical lobe, the stronger the bias to turn leftwards. To our knowledge, this is the first study to demonstrate a relationship at the individual level between brain and behavioral asymmetries in invertebrates.
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http://dx.doi.org/10.1016/j.bbr.2012.05.042DOI Listing
September 2012

Alternative sites of synaptic plasticity in two homologous "fan-out fan-in" learning and memory networks.

Curr Biol 2011 Nov 20;21(21):1773-82. Epub 2011 Oct 20.

Department of Neurobiology, Life Sciences Institute and the Interdisciplinary Center for Neural Computation, Hebrew University, Jerusalem 91904, Israel.

Background: To what extent are the properties of neuronal networks constrained by computational considerations? Comparative analysis of the vertical lobe (VL) system, a brain structure involved in learning and memory, in two phylogenetically close cephalopod mollusks, Octopus vulgaris and the cuttlefish Sepia officinalis, provides a surprising answer to this question.

Results: We show that in both the octopus and the cuttlefish the VL is characterized by the same simple fan-out fan-in connectivity architecture, composed of the same three neuron types. Yet, the sites of short- and long-term synaptic plasticity and neuromodulation are different. In the octopus, synaptic plasticity occurs at the fan-out glutamatergic synaptic layer, whereas in the cuttlefish plasticity is found at the fan-in cholinergic synaptic layer.

Conclusions: Does this dramatic difference in physiology imply a difference in function? Not necessarily. We show that the physiological properties of the VL neurons, particularly the linear input-output relations of the intermediate layer neurons, allow the two different networks to perform the same computation. The convergence of different networks to the same computational capacity indicates that it is the computation, not the specific properties of the network, that is self-organized or selected for by evolutionary pressure.
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http://dx.doi.org/10.1016/j.cub.2011.09.011DOI Listing
November 2011

Does kainic acid induce partial brain lesion in an invertebrate model: sepia officinalis? Comparison with electrolytic lesion.

Brain Res 2008 Oct 8;1238:44-52. Epub 2008 Aug 8.

Groupe Mémoire et Plasticité comportementale, Esplanade de la Paix, Université de Caen Basse Normandie, 14032 Caen cedex, France.

The present study investigates the feasibility of excitotoxic lesions in the cuttlefish in the mapping of brain functions in Cephalopods. Adult animals were injected locally with a neurotoxin, kainic acid. The brain region receiving the neurotoxin was the vertical lobe, a key brain structure for learning and memory processes. Brain damage induced by these injections was evaluated using different histological stainings: hematoxilin-eosin, Fink-Heimer and DAPI. The results were compared with histological changes after electrolytic lesion of the vertical lobe. Neurodegeneration was revealed in and around the injection site: an intense area of proliferative cells, degenerating terminal axon ramifications and cell death. In comparison with electrolytic lesion, excitotoxic lesion displays important advantages, since fibres of passage are not destroyed by kainic acid injection, which induces only a restricted lesion and so is an appropriate method of investigating the role of the vertical lobe or other brain regions in a Cephalopod model, Sepia officinalis.
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http://dx.doi.org/10.1016/j.brainres.2008.08.002DOI Listing
October 2008

Effects of dorsal and ventral vertical lobe electrolytic lesions on spatial learning and locomotor activity in Sepia officinalis.

Behav Neurosci 2006 Oct;120(5):1151-8

Laboratoire de Physiologie du Comportement des Cephalopodes, Universite de Caen Basse-Normandie, Caen, France.

This study aims to analyze the effects of electrolytic lesion, restricted to either the ventral or the dorsal parts of the vertical lobe (VL), on the behavior of cuttlefish (Sepia officinalis). Two behavioral tests were performed on sham-operated and lesioned cuttlefish: assessment of locomotor activity in an open field and determination of spatial learning abilities in a T maze. The results showed that ventral lesions of the VL led to marked impairment in the acquisition of spatial learning, whereas dorsal lesions of the VL increased locomotor activity in the open field and impaired long-term retention of spatial learning. This study establishes for the first time the existence of distinct functions in the ventral and the dorsal parts of the VL in cephalopods.
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http://dx.doi.org/10.1037/0735-7044.120.5.1151DOI Listing
October 2006

In vitro evidence and age-related changes for nicotinic but not muscarinic acetylcholine receptors in the central nervous system of Sepia officinalis.

Neurosci Lett 2005 Oct;387(3):162-7

Laboratoire de Psychophysiologie du Comportement des Céphalopodes, Université de Caen, Esplanade de la Paix, 14032 Caen Cedex, France.

Binding putative muscarinic ([3H]-NMS and [3H]-QNB) or nicotinic ([3H]-cytisine) acetylcholine receptors was quantitatively studied through the use of in vitro binding experiments on either membrane preparations or brain sections of juvenile (3 months), mature (15 months) or senescent (23 months) cuttlefish. No specific binding could be detected with muscarinic receptor ligands under any of the experimental conditions employed (ligand concentrations, buffers, ionic charges, types of tissue, i.e., brain sections or membrane preparations). On the other hand, [3H]-cytisine demonstrated a specific and saturable binding with a single class of high affinity binding sites (Kd of 2.6-34.6 nM; Bmax of 128-1682 fmol/mg tissue equivalent, depending on the central structure). This binding was found to be heterogeneous throughout the central regions (optic lobe>pedal lobe; superior frontal lobe>...precommissural lobe; vertical lobe>...anterior basal lobe; subvertical lobe; inferior frontal lobe; median basal lobe). These results question the existence of muscarinic-like receptors in the cuttlefish brain, or at least of a pharmacological dissimilarity from vertebrate muscarinic receptors. In contrast, nicotinic-like receptors are widely present; interestingly, their density was found to be significantly reduced in most nervous central lobes of senescent cuttlefish when compared with mature animals. The most significant decrease (-71%) was found in the anterior part of the superior frontal lobe, which is involved in visual learning; this might be related to the changes, previously demonstrated, in cholinergic neurons in this lobe in the course of aging.
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http://dx.doi.org/10.1016/j.neulet.2005.06.017DOI Listing
October 2005

Changes in cholinergic enzyme activities in the cuttlefish brain during memory formation.

Physiol Behav 2003 Sep;79(4-5):749-56

Laboratoire de Psychophysiologie, Université de Caen, Esplanade de la Paix, 14032, Caen, France.

Cephalopods are promising invertebrate models to investigate the neurobiology of learning and memory due to their advanced behavioral abilities. In the present study, acetylcholine synthesis and catabolism were studied in various central nervous system (CNS) regions of cuttlefish subjected to associative learning procedures with different retention delays, with the aim of characterizing the involvement of cholinergic neurotransmission in learning and memory processes in this species. In the first experiment, the acquisition procedure consisted of a single continuous trial. As a response to a short retention delay (60 min), when compared to control or to a very short retention delay (2 min), cholinergic enzymatic activities decreased in structures involved in learning and memory (vertical-subvertical lobes) and in lower motor centers (brachial and pedal lobes). In the second experiment, the same learning paradigm was used but with repeated trials. In this case, a long-term retention (24 h) induced an increase in acetylcholine catabolism in the pedal and optic lobes (lower motor and higher centers, respectively) when compared to control. These results suggest the occurrence of different regulatory mechanisms of cholinergic enzymes as a response to memory formation with a long- or a short-term retention delay.
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http://dx.doi.org/10.1016/s0031-9384(03)00188-4DOI Listing
September 2003