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Grigoryan GA. The systemic effects of the enriched environment on the conditioned fear reaction. Front Behav Neurosci 2023; 17:1227575. [PMID: 37674611 PMCID: PMC10477375 DOI: 10.3389/fnbeh.2023.1227575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 08/07/2023] [Indexed: 09/08/2023] Open
Abstract
In this review, a hypothesis is proposed to explain the beneficial effect of an enriched environment (EE) on the conditioned fear reaction (CFR) from the perspective of a functional system of behavioral control. According to the hypothesis, the EE affects all behavioral act components, including the processing of sensory information, memory, motivational and reinforcing systems, and motor activities, which weakens the CFR. Animals raised in the EE have effects that are comparable to those of context (CTX) and CS pre-exposures at latent inhibition. An abundance of stimuli in the EE and constant contact with them provide the formation of CS-noUS and CTX-noUS connections that later, during CFR learning, slow down and diminish fear. The EE also contributes to faster processing of information and habituation to it. As a result, many stimuli in the context lose their significance, and subjects simply ignore them. And finally, the EE affects the motivational and reinforcing brain mechanisms, induces an impairment of search activity, and worsens memory consolidation, which leads to a reduction of CFR.
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Affiliation(s)
- Grigory A. Grigoryan
- The Laboratory of Conditioned Reflexes and Physiology of Emotions, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
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Casalini A, Gentile L, Emmanuele P, Brusa R, Elmi A, Parmeggiani A, Galosi L, Roncarati A, Mordenti O. Effects of Environmental Enrichment on the Behavior of Octopus vulgaris in a Recirculating Aquaculture System. Animals (Basel) 2023; 13:1862. [PMID: 37889785 PMCID: PMC10251970 DOI: 10.3390/ani13111862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/15/2023] [Accepted: 06/01/2023] [Indexed: 10/29/2023] Open
Abstract
Octopus vulgaris is a commercially valuable species. It is overexploited in the natural environment and is considered to be an innovative species for aquaculture. However, large-scale farming is generally designed only based on economic requirements, disregarding any form of enrichment that induces the natural behavior of aquatic species. Although many studies have shown the influence of environmental enrichment on terrestrial vertebrates, fish, and cephalopod mollusks, information on the effect of environmental enrichment on the body patterns of O. vulgaris is limited. Therefore, in this study, we assessed how different environmental conditions (Basic vs. Enriched) affect sub-adults of O. vulgaris kept in recirculation systems, through qualitative-quantitative studies of the main body patterns and their potential application in the commercial production of this species. The results indicated that octopuses kept in the enriched environment showed several body patterns and gained a significantly higher weight than those kept in the basic environment. The body patterns displayed by the individuals kept in the basic environment were similar to those exhibited under situations of hostility and inter/intra-specific conflict. Hence, the environment of octopuses needs to be enriched, especially for the large-scale production of this species.
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Affiliation(s)
- Antonio Casalini
- Department of Veterinary Medical Sciences—DIMEVET, University of Bologna, Via Tolara di Sopra 50, Ozzano dell’Emilia, 40064 Bologna, Italy; (A.C.); (P.E.); (R.B.); (A.E.); (A.P.); (O.M.)
| | - Laura Gentile
- Department of Veterinary Medical Sciences—DIMEVET, University of Bologna, Via Tolara di Sopra 50, Ozzano dell’Emilia, 40064 Bologna, Italy; (A.C.); (P.E.); (R.B.); (A.E.); (A.P.); (O.M.)
| | - Pietro Emmanuele
- Department of Veterinary Medical Sciences—DIMEVET, University of Bologna, Via Tolara di Sopra 50, Ozzano dell’Emilia, 40064 Bologna, Italy; (A.C.); (P.E.); (R.B.); (A.E.); (A.P.); (O.M.)
| | - Riccardo Brusa
- Department of Veterinary Medical Sciences—DIMEVET, University of Bologna, Via Tolara di Sopra 50, Ozzano dell’Emilia, 40064 Bologna, Italy; (A.C.); (P.E.); (R.B.); (A.E.); (A.P.); (O.M.)
| | - Alberto Elmi
- Department of Veterinary Medical Sciences—DIMEVET, University of Bologna, Via Tolara di Sopra 50, Ozzano dell’Emilia, 40064 Bologna, Italy; (A.C.); (P.E.); (R.B.); (A.E.); (A.P.); (O.M.)
| | - Albamaria Parmeggiani
- Department of Veterinary Medical Sciences—DIMEVET, University of Bologna, Via Tolara di Sopra 50, Ozzano dell’Emilia, 40064 Bologna, Italy; (A.C.); (P.E.); (R.B.); (A.E.); (A.P.); (O.M.)
| | - Livio Galosi
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Circonvallazione 93/95, 62024 Matelica, Italy; (L.G.); (A.R.)
| | - Alessandra Roncarati
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Circonvallazione 93/95, 62024 Matelica, Italy; (L.G.); (A.R.)
| | - Oliviero Mordenti
- Department of Veterinary Medical Sciences—DIMEVET, University of Bologna, Via Tolara di Sopra 50, Ozzano dell’Emilia, 40064 Bologna, Italy; (A.C.); (P.E.); (R.B.); (A.E.); (A.P.); (O.M.)
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Vesicular Zinc Modulates Cell Proliferation and Survival in the Developing Hippocampus. Cells 2023; 12:cells12060880. [PMID: 36980221 PMCID: PMC10047515 DOI: 10.3390/cells12060880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 03/09/2023] [Indexed: 03/16/2023] Open
Abstract
In the brain, vesicular zinc, which refers to a subset of zinc that is sequestered into synaptic vesicles by zinc transporter 3 (ZnT3), has extensive effects on neuronal signalling and modulation. Vesicular zinc-focused research has mainly been directed to its role in the hippocampus, particularly in adult neurogenesis. However, whether vesicular zinc is involved in modulating neurogenesis during the early postnatal period has been less studied. As a first step to understanding this, we used ZnT3 knockout (KO) mice, which lack ZnT3 and, thus, vesicular zinc, to evaluate cell proliferation at three different age points spanning postnatal development (P6, P14, and P28). The survival and the neuronal phenotype of these cells was also assessed in adulthood. We found that male ZnT3 KO mice exhibited lower rates of cell proliferation at P14, but a greater number of these cells survived to adulthood. Additionally, significantly more cells labelled on P6 survived to adulthood in male and female ZnT3 KO mice. We also found sex-dependent differences, whereby male mice showed higher levels of cell proliferation at P28, as well as higher levels of cell survival for P14-labelled cells, compared to female mice. However, female mice showed greater percentages of neuronal differentiation for P14-labelled cells. Finally, we found significant effects of age of BrdU injections on cell proliferation, survival, and neuronal differentiation. Collectively, our results suggest that the loss of vesicular zinc affects normal proliferation and survival of cells born at different age points during postnatal development and highlight prominent sex- and age-dependent differences. Our findings provide the foundation for future studies to further probe the role of vesicular zinc in the modulation of developmental neurogenesis.
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Kapusta J, Siewierska D, Kruczek M, Pochron E, Olejniczak P. Species specific differences in short-term behavioral reaction of voles to cage elements removal. Appl Anim Behav Sci 2023. [DOI: 10.1016/j.applanim.2023.105899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
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Welfare of encaged rodents: Species specific behavioral reaction of voles to new enrichment items. Appl Anim Behav Sci 2022. [DOI: 10.1016/j.applanim.2021.105522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zhou F, Yin G, Gao Y, Ouyang L, Liu S, Jia Q, Yu H, Zha Z, Wang K, Xie J, Fan Y, Shao L, Feng C, Fan G. Insights into cognitive deficits caused by low-dose toxic heavy metal mixtures and their remediation through a postnatal enriched environment in rats. JOURNAL OF HAZARDOUS MATERIALS 2020; 388:122081. [PMID: 31958610 DOI: 10.1016/j.jhazmat.2020.122081] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 12/27/2019] [Accepted: 01/12/2020] [Indexed: 06/10/2023]
Abstract
The heavy metals, namely lead (Pb), cadmium (Cd), and mercury (Hg), have been studied extensively in various independent studies. It has been seen that these metals are usually detected simultaneously in the human blood at low levels. However, it is unknown whether exposure to these heavy metal mixtures (MM) can induce neurological damages at these low levels. Therefore, we investigated the influence of the Pb, Cd, and Hg mixture on the nervous system in rats at exposure doses equivalent to those normally found in the human blood. After pregnant rats being exposed to MM via drinking water throughout the gestation and lactation, their offspring were followed-up till adulthood. MM caused cognitive deficits and impairments in a dose-dependent manner. Furthermore, MM disrupted dendritic spines, the structural basis of learning and memory, and induced changes in spine-related pathways. Meanwhile, we explored an early and safe way to remedy these impairments through a postnatal enriched environment. The enriched environment ameliorated MM-impaired cognitive function, synaptic plasticity, and spine-related pathways. This study demonstrated that low-dose co-exposure to Pb, Cd, and Hg can cause cognitive and synaptic plasticity deficits and timely intervention through the enriched environment has a certain corrective effect.
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Affiliation(s)
- Fankun Zhou
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China
| | - Guangming Yin
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China
| | - Yanyan Gao
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China
| | - Lu Ouyang
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China
| | - Sisi Liu
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China
| | - Qiyue Jia
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China
| | - Han Yu
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China
| | - Zhipeng Zha
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China
| | - Kai Wang
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China
| | - Jie Xie
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China
| | - Ying Fan
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China
| | - Lijian Shao
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China
| | - Chang Feng
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China
| | - Guangqin Fan
- Department of Occupational Health and Toxicology, School of Public Health, Nanchang University, Nanchang 330006, PR China; Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang 330006, PR China.
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Schroyens N, Bender CL, Alfei JM, Molina VA, Luyten L, Beckers T. Post-weaning housing conditions influence freezing during contextual fear conditioning in adult rats. Behav Brain Res 2018; 359:172-180. [PMID: 30391556 PMCID: PMC6314464 DOI: 10.1016/j.bbr.2018.10.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/30/2018] [Accepted: 10/30/2018] [Indexed: 01/14/2023]
Abstract
The present study aimed to investigate the influence of housing conditions on contextual fear memory malleability. Male Wistar rats were housed in enriched, standard, or impoverished conditions after weaning and remained in these conditions throughout the entire experiment. After six weeks into those housing conditions, all animals underwent a 3-day protocol including contextual fear conditioning (day 1), memory reactivation followed by systemic administration of midazolam or vehicle (day 2), and a retention test (day 3). Percentage freezing was used as a behavioral measure of contextual fear. There was no evidence for an effect of housing conditions on the sensitivity of contextual fear memory to amnestic effects of post-reactivation midazolam administration, and no indication for amnestic effects of post-reactivation midazolam overall (including in the standard group). The inability to replicate previous demonstrations of post-reactivation amnesia using the same protocol underscores the subtle nature of post-reactivation pharmacological memory interference. Notably, impoverished housing resulted in a decrease in contextual freezing during contextual fear conditioning, reactivation and retention testing, compared to enriched and standard housing conditions. This observation warrants caution when interpreting the results from experiments regarding effects of housing on fear memory processes, particularly when freezing is used as a measure of fear.
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Affiliation(s)
- Natalie Schroyens
- Centre for the Psychology of Learning and Experimental Psychopathology, Department of Psychology, KU Leuven, Tiensestraat 102 bus 3712, 3000 Leuven, Belgium.
| | - Crhistian Luis Bender
- Instituto de Farmacología Experimental de Córdoba-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
| | - Joaquín Matias Alfei
- Centre for the Psychology of Learning and Experimental Psychopathology, Department of Psychology, KU Leuven, Tiensestraat 102 bus 3712, 3000 Leuven, Belgium.
| | - Victor Alejandro Molina
- Instituto de Farmacología Experimental de Córdoba-CONICET, Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
| | - Laura Luyten
- Centre for the Psychology of Learning and Experimental Psychopathology, Department of Psychology, KU Leuven, Tiensestraat 102 bus 3712, 3000 Leuven, Belgium.
| | - Tom Beckers
- Centre for the Psychology of Learning and Experimental Psychopathology, Department of Psychology, KU Leuven, Tiensestraat 102 bus 3712, 3000 Leuven, Belgium; Leuven Brain Institute, 3000 Leuven, Belgium.
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Sampedro-Piquero P, Álvarez-Suárez P, Moreno-Fernández RD, García-Castro G, Cuesta M, Begega A. Environmental Enrichment Results in Both Brain Connectivity Efficiency and Selective Improvement in Different Behavioral Tasks. Neuroscience 2018; 388:374-383. [PMID: 30086366 DOI: 10.1016/j.neuroscience.2018.07.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 12/26/2022]
Abstract
Exposure to environmental enrichment (EE) has been a useful model for studying the effects of experience on brain plasticity, but to date, few is known about the impact of this condition on the brain functional networks that probably underlies the multiple behavioral improvements. Hence, we assessed the effect of an EE protocol in adult Wistar rats on the performance in several behavioral tasks testing different domains (Open field (OP): locomotor activity; Elevated-zero maze (EZM): anxiety-related behaviors; 5-choice serial reaction time task (5-CSRTT): attentional processes; 4-arm radial water maze (4-RAWM): spatial memory) in order to check its effectiveness in a wide range of functions. After this, we analyzed the functional brain connectivity underlying each experimental condition through cytochrome C oxidase (COx) histochemistry. Our EE protocol reduced both locomotor activity in the OP and anxiety-related behaviors in the EZM. On the other hand, enriched rats showed more accuracy in the 4-RAWM, whereas 5-CSRTT performance was not significantly ameliorated by EE condition. In relation to COx functional connectivity, we found that EE reduced the number of strong positive correlations both in basal and training conditions, suggesting a modulating effect on specific brain connections. Our results suggest that EE seems to have a selective effect on specific brain regions, such as prefrontal cortex and hippocampus, leading to a more efficient brain connectivity.
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Affiliation(s)
- P Sampedro-Piquero
- Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento, Instituto de Investigación Biomédica de Málaga (IBIMA), Facultad de Psicología, Universidad de Málaga, Spain.
| | | | - R D Moreno-Fernández
- Departamento de Psicobiología y Metodología de las Ciencias del Comportamiento, Instituto de Investigación Biomédica de Málaga (IBIMA), Facultad de Psicología, Universidad de Málaga, Spain
| | - G García-Castro
- Instituto de Neurociencias del Principado de Asturias INEUROPA, Departamento de Psicología, Facultad de Psicología, Universidad de Oviedo, Spain
| | - M Cuesta
- Instituto de Neurociencias del Principado de Asturias INEUROPA, Departamento de Psicología, Facultad de Psicología, Universidad de Oviedo, Spain
| | - A Begega
- Instituto de Neurociencias del Principado de Asturias INEUROPA, Departamento de Psicología, Facultad de Psicología, Universidad de Oviedo, Spain
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Hegde P, O'Mara S, Laxmi TR. Extinction of Contextual Fear with Timed Exposure to Enriched Environment: A Differential Effect. Ann Neurosci 2017; 24:90-104. [PMID: 28588364 DOI: 10.1159/000475898] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 01/30/2017] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Extinction of fear memory depends on the environmental and emotional cues. Furthermore, consolidation of extinction is also dependent on the environmental exposure. But, the relationship of the time of the exposure to a variety of environmental cues is not well known. The important region involved in facilitation of extinction of fear memory is through diversion of the flow of information leaving the lateral nucleus of amygdala. PURPOSE The study aimed to address a question to explain how these brain regions react to environmental stimulation during the retention and extinction of fear memory. METHODS An enriched environment (EE) is assumed to mediate extinction of fear memory, we examined the apparent discrepancy between the effects of defensive response, the freezing behavior induced by Pavlovian classical fear conditioning by subjecting them to variance in the timing to EE. The different timing of EE exposure was 10 days of EE either before fear conditioning and/or after extinction training to the rats. The local field potentials was recorded from CA1 hippocampus, lateral nucleus of amygdala and infralimbic region of medial prefrontal cortex (mPFC) during the fear learning and extinction from the control rats and rats exposed to EE before and after fear conditioning. RESULTS Exposure to EE before the fear conditioning and after extinction training was more effective in the extinction fear memory. In addition, we also found switching from exploratory locomotion to freezing during retention of contextual fear memory which was associated with decreased theta power and reduced synchronized theta oscillations in CA1-hippocampus, lateral nucleus of amygdala, and infralimbic region of mPFC. CONCLUSION Thus, we propose that the timing of exposure to EE play a key role in the extinction of fear memory.
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Affiliation(s)
- Preethi Hegde
- Department of Neurophysiology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Shane O'Mara
- School of Psychology and Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Thenkanidiyoor Rao Laxmi
- Department of Neurophysiology, National Institute of Mental Health and Neurosciences, Bangalore, India
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Lach G, Bicca MA, Hoeller AA, Santos ECDS, Costa APR, de Lima TCM. Short-term enriched environment exposure facilitates fear extinction in adult rats: The NPY-Y1 receptor modulation. Neuropeptides 2016; 55:73-8. [PMID: 26490304 DOI: 10.1016/j.npep.2015.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 09/30/2015] [Accepted: 10/01/2015] [Indexed: 12/14/2022]
Abstract
Neuropeptides have an important role in several psychiatric conditions. Among them, neuropeptide Y (NPY) seems to be essential to modulate some features of stress-related disorders. Post-traumatic stress disorder (PTSD), characterized by inappropriate fear generalization to safe situations may be modulated by NPY manipulation since this neuropeptide is involved in the promotion of coping with stress. Experimentally, coping strategies have been obtained after exposure in enriched environment (EE) rather than standard one. Thus, in the present study we aimed to assess whether short-term EE situation and NPY-Y1 receptor (Y1r) modulation may affect the extinction of contextual fear conditioning, an experimental approach to PTSD. Here we show that EE-rats have the contextual fear extinction facilitated, and this facilitation was reverted by central infusion of BIBO3304, a nonpeptide Y1r antagonist. In addition, protein analysis revealed an upregulation of hippocampal Y1r in conditioned EE-rats, but no changes were observed in EE-rats that were not conditioned. Our results demonstrated that protective properties of EE on fear extinction can be regulated, at least in part, by activation of NPY-signaling through Y1r within hippocampus, an area that plays a major role in contextual memories. Overall, the activation of Y1r is important to promote better and faster perception of self-location (context), and to reduce fear generalization in rats exposed to EE.
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Affiliation(s)
- Gilliard Lach
- Department of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, SC 88049-900, Brazil.
| | - Maira Assunção Bicca
- Department of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, SC 88049-900, Brazil
| | - Alexandre Ademar Hoeller
- Department of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, SC 88049-900, Brazil; Postgraduate Program in Medical Science, Center of Health Sciences, University Hospital, Federal University of Santa Catarina, Florianópolis, SC 88040-970, Brazil
| | - Evelyn Cristina da Silva Santos
- Department of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, SC 88049-900, Brazil
| | - Ana Paula Ramos Costa
- Department of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, SC 88049-900, Brazil
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Hannan AJ. Environmental enrichment and brain repair: harnessing the therapeutic effects of cognitive stimulation and physical activity to enhance experience-dependent plasticity. Neuropathol Appl Neurobiol 2014; 40:13-25. [PMID: 24354721 DOI: 10.1111/nan.12102] [Citation(s) in RCA: 170] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 11/29/2013] [Indexed: 12/12/2022]
Abstract
Environmental enrichment (EE) increases levels of novelty and complexity, inducing enhanced sensory, cognitive and motor stimulation. In wild-type rodents, EE has been found to have a range of effects, such as enhancing experience-dependent cellular plasticity and cognitive performance, relative to standard-housed controls. Whilst environmental enrichment is of course a relative term, dependent on the nature of control environmental conditions, epidemiological studies suggest that EE has direct clinical relevance to a range of neurological and psychiatric disorders. EE has been demonstrated to induce beneficial effects in animal models of a wide variety of brain disorders. The first evidence of beneficial effects of EE in a genetically targeted animal model was generated using Huntington's disease transgenic mice. Subsequent studies found that EE was also therapeutic in mouse models of Alzheimer's disease, consistent with epidemiological studies of relevant environmental modifiers. EE has also been found to ameliorate behavioural, cellular and molecular deficits in animal models of various neurological and psychiatric disorders, including Parkinson's disease, stroke, traumatic brain injury, epilepsy, multiple sclerosis, depression, schizophrenia and autism spectrum disorders. This review will focus on the effects of EE observed in animal models of neurodegenerative brain diseases, at molecular, cellular and behavioural levels. The proposal that EE may act synergistically with other approaches, such as drug and cell therapies, to facilitate brain repair will be discussed. I will also discuss the therapeutic potential of 'enviromimetics', drugs which mimic or enhance the therapeutic effects of cognitive activity and physical exercise, for both neuroprotection and brain repair.
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Affiliation(s)
- A J Hannan
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne Brain Centre, Melbourne, Victoria, Australia
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Absence of Ca2+-stimulated adenylyl cyclases leads to reduced synaptic plasticity and impaired experience-dependent fear memory. Transl Psychiatry 2012; 2:e126. [PMID: 22832970 PMCID: PMC3365269 DOI: 10.1038/tp.2012.50] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Ca(2+)-stimulated adenylyl cyclase (AC) 1 and 8 are two genes that have been shown to play critical roles in fear memory. AC1 and AC8 couple neuronal activity and intracellular Ca(2+) increases to the production of cyclic adenosine monophosphate and are localized synaptically, suggesting that Ca(2+)-stimulated ACs may modulate synaptic plasticity. Here, we first established that Ca(2+)-stimulated ACs modulate protein markers of synaptic activity at baseline and after learning. Primary hippocampal cell cultures showed that AC1/AC8 double-knockout (DKO) mice have reduced SV2, a synaptic vesicle protein, abundance along their dendritic processes, and this reduction can be rescued through lentivirus delivery of AC8 to the DKO cells. Additionally, phospho-synapsin, a protein implicated in the regulation of neurotransmitter release at the synapse, is decreased in vivo 1 h after conditioned fear (CF) training in DKO mice. Importantly, additional experiments showed that long-term potentiation deficits present in DKO mice are rescued by acutely replacing AC8 in the forebrain, further supporting the idea that Ca(2+)-stimulated AC activity is a crucial modulator of synaptic plasticity. Previous studies have demonstrated that memory is continually modulated by gene-environment interactions. The last set of experiments evaluated the effects of knocking out AC1 and AC8 genes on experience-dependent changes in CF memory. We showed that the strength of CF memory in wild-type mice is determined by previous environment, minimal or enriched, whereas memory in DKO mice is unaffected. Thus, overall these results show that AC1 and AC8 modulate markers of synaptic activity and help integrate environmental information to modulate fear memory.
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Impact of mGluR5 during amphetamine-induced hyperactivity and conditioned hyperactivity in differentially reared rats. Psychopharmacology (Berl) 2012; 221:227-37. [PMID: 22139452 DOI: 10.1007/s00213-011-2565-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 10/28/2011] [Indexed: 12/23/2022]
Abstract
RATIONALE 3-((2-Methyl-1,3-thiazol-4-yl)ethynyl)pyridine hydrochloride (MTEP) is a metabotropic glutamate receptor 5 (mGluR5) antagonist that may alter drug sensitivity in differentially reared rats due to its involvement in the psychostimulant reward pathway and plasticity. OBJECTIVES The purpose of this study was to assess the effects of MTEP on acute amphetamine-induced hyperactivity, conditioned hyperactivity, and sensitization. METHODS Rats were reared in an enriched (EC), isolated (IC), or standard (SC) condition after which rats were either administered MTEP (1.0 mg/kg, ip) or saline prior to an acute (0.5 or 1.0 mg/kg, sc) or repeated (0.3 mg/kg, sc) amphetamine exposure. Rats undergoing repeated amphetamine exposure were administered MTEP prior to conditioned hyperactivity and sensitization tests. RESULTS EC and SC rats administered with MTEP prior to acute amphetamine demonstrated attenuated amphetamine-induced locomotor activity compared to controls, while IC rats administered MTEP following repeated amphetamine exposure demonstrated attenuated amphetamine-induced locomotor activity. Interestingly, MTEP treatment only altered conditioned hyperactivity in EC rats, as MTEP pretreatment resulted in conditioned hyperactivity in EC rats while conditioned hyperactivity was not observed in EC rats pretreated with saline. CONCLUSIONS Glutamatergic pathways are altered during differential rearing, which differentially alters the role of mGluR5 in EC, IC, and SC rats when administered psychostimulant acutely versus repeatedly. These findings suggest that differential rearing alters glutamatergic function, which reduces sensitivity to psychostimulants.
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Malik R, Chattarji S. Enhanced intrinsic excitability and EPSP-spike coupling accompany enriched environment-induced facilitation of LTP in hippocampal CA1 pyramidal neurons. J Neurophysiol 2012; 107:1366-78. [DOI: 10.1152/jn.01009.2011] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Environmental enrichment (EE) is a well-established paradigm for studying naturally occurring changes in synaptic efficacy in the hippocampus that underlie experience-induced modulation of learning and memory in rodents. Earlier research on the effects of EE on hippocampal plasticity focused on long-term potentiation (LTP). Whereas many of these studies investigated changes in synaptic weight, little is known about potential contributions of neuronal excitability to EE-induced plasticity. Here, using whole-cell recordings in hippocampal slices, we address this gap by analyzing the impact of EE on both synaptic plasticity and intrinsic excitability of hippocampal CA1 pyramidal neurons. Consistent with earlier reports, EE increased contextual fear memory and dendritic spine density on CA1 cells. Furthermore, EE facilitated LTP at Schaffer collateral inputs to CA1 pyramidal neurons. Analysis of the underlying causes for enhanced LTP shows EE to increase the frequency but not amplitude of miniature excitatory postsynaptic currents. However, presynaptic release probability, assayed using paired-pulse ratios and use-dependent block of N-methyl-d-aspartate receptor currents, was not affected. Furthermore, CA1 neurons fired more action potentials (APs) in response to somatic depolarization, as well as during the induction of LTP. EE also reduced spiking threshold and after-hyperpolarization amplitude. Strikingly, this EE-induced increase in excitability caused the same-sized excitatory postsynaptic potential to fire more APs. Together, these findings suggest that EE may enhance the capacity for plasticity in CA1 neurons, not only by strengthening synapses but also by enhancing their efficacy to fire spikes—and the two combine to act as an effective substrate for amplifying LTP.
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Affiliation(s)
- Ruchi Malik
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Sumantra Chattarji
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
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The impact of environmental enrichment in laboratory rats--behavioural and neurochemical aspects. Behav Brain Res 2011; 222:246-64. [PMID: 21504762 DOI: 10.1016/j.bbr.2011.04.002] [Citation(s) in RCA: 309] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 03/28/2011] [Accepted: 04/03/2011] [Indexed: 12/13/2022]
Abstract
The provision of environmental enrichment (EE) for laboratory rats is recommended in European guidelines governing laboratory animal welfare. It is believed the EE implementation can improve animals' well-being and EE has been used to demonstrate learning and plasticity of the brain in response to the environment. This review suggests that the definition and duration of EE varies considerably across laboratories. Notwithstanding this, some EE protocols have revealed profound effects on brain neurochemistry and resulting behaviour, suggesting that EE can have the potential to significantly modify these parameters in rats. For this review, a literature search was conducted using PubMed and the search terms "Environmental Enrichment" and "rats". From the results of this search the most important variables for consideration in the implementation of EE are identified and summarised, and include cage size and housing density; rat age, sex and strain; duration of EE; the EE protocol and enrichment items employed; and the use of appropriate controls. The effects of EE in a number of behavioural tests and its effects on neurotransmitters, neurotrophic factors, stress hormones and neurogenesis and proliferation are outlined. The findings summarised in the present review show the range of EE protocols employed and their effects in tests of activity, learning and affect, as well neurochemical effects which mediate enhanced plasticity in the brain. EE, as is provided in many laboratories, may be of benefit to the animals, however it is important that future work aims to provide a better understanding of EE effects on research outcomes.
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16
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Attention and memory in aged rats: Impact of lifelong environmental enrichment. Neurobiol Aging 2011; 32:718-36. [DOI: 10.1016/j.neurobiolaging.2009.03.012] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 02/02/2009] [Accepted: 03/24/2009] [Indexed: 02/03/2023]
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Frick KM, Benoit JD. Use it or lose it: environmental enrichment as a means to promote successful cognitive aging. ScientificWorldJournal 2010; 10:1129-41. [PMID: 20563536 PMCID: PMC4462190 DOI: 10.1100/tsw.2010.111] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Environmental enrichment has become increasingly utilized in rodent models of aging and neurodegenerative disease in order to prevent or reverse cognitive decline and neuronal dysfunction. However, the potential application of this body of work to human cognitive aging has rarely been discussed. The present article provides an overview of the rodent research that has tested the effects of environmental enrichment on hippocampal and neocortical function, and the types of memories mediated by these brain regions. Although data from models of neurodegenerative disease are presented, primary emphasis is given to studies of aging rodents and to methodological issues (e.g., age, treatment duration, treatment type) central to the mnemonic effectiveness of enrichment treatment. The implications of this work for human cognitive aging are discussed.
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Affiliation(s)
- Karyn M Frick
- 1Department of Psychology, Yale University, New Haven, CT, USA.
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Petrosini L, De Bartolo P, Foti F, Gelfo F, Cutuli D, Leggio MG, Mandolesi L. On whether the environmental enrichment may provide cognitive and brain reserves. ACTA ACUST UNITED AC 2009; 61:221-39. [DOI: 10.1016/j.brainresrev.2009.07.002] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 07/10/2009] [Accepted: 07/14/2009] [Indexed: 11/27/2022]
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19
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Does environmental enrichment affect the behaviour of fish commonly used in laboratory work? Appl Anim Behav Sci 2009. [DOI: 10.1016/j.applanim.2009.02.017] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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Graham BM, Richardson R. Acute systemic fibroblast growth factor-2 enhances long-term memory in developing rats. Neurobiol Learn Mem 2009; 91:424-30. [DOI: 10.1016/j.nlm.2008.12.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 12/08/2008] [Accepted: 12/09/2008] [Indexed: 10/21/2022]
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21
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Coolon RA, Cain ME. Effects of mecamylamine on nicotine-induced conditioned hyperactivity and sensitization in differentially reared rats. Pharmacol Biochem Behav 2009; 93:59-66. [PMID: 19379770 DOI: 10.1016/j.pbb.2009.04.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Revised: 04/12/2009] [Accepted: 04/13/2009] [Indexed: 10/20/2022]
Abstract
Rats reared in an enriched condition (EC) display less sensitization to nicotine than rats reared in an impoverished condition (IC). However, it is unknown what effect differential rearing has on nicotine-induced conditioned hyperactivity. The present study determined whether differential rearing affects nicotine-induced conditioned hyperactivity. This study also examined the effects of mecamylamine on conditioned hyperactivity and sensitization. EC, IC, and social condition (SC) rats were reared from 21 to 51 days of age before receiving repeated nicotine injections (.4 mg/kg) prior to 1-h locomotor sessions. Following the conditioned-hyperactivity test, rats received additional training sessions followed by a drug-free rest period before the sensitization test. Mecamylamine (1.0 mg/kg) was administered prior to the conditioned-hyperactivity test and sensitization test. Nicotine treatment resulted in sensitization and conditioned hyperactivity in all differential rearing groups. EC rats displayed less locomotor activity in response to nicotine than both IC and SC rats. Pretreatment with mecamylamine blocked the expression of conditioned hyperactivity only in EC and SC rats and attenuated sensitization in all three rearing groups. These findings suggest that environmental enrichment may alter nicotinic acetylcholine receptors during development and may be a protective factor in the initiation and relapse of smoking behavior.
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Affiliation(s)
- Rosemary A Coolon
- Kansas State University, Department of Psychology, 418 Bluemont Hall, 1100 Mid-Campus Drive, Manhattan, KS 66506-5302, USA
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22
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Manciocco A, Chiarotti F, Vitale A, Calamandrei G, Laviola G, Alleva E. The application of Russell and Burch 3R principle in rodent models of neurodegenerative disease: the case of Parkinson's disease. Neurosci Biobehav Rev 2008; 33:18-32. [PMID: 18771685 DOI: 10.1016/j.neubiorev.2008.08.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Revised: 07/10/2008] [Accepted: 08/07/2008] [Indexed: 12/21/2022]
Abstract
Currently, the accepted ethical standards for the regulation of animal experimentation are provided by the 3R principle (Replacement, Reduction and Refinement). The development of alternative methods to the use of animals (Replacement), the design of adequate experimental protocols to reduce the number of animals (Reduction), the application of refinement practices (Refinement) are all aspects to be considered to ensure ethical and scientific validity to animal experimentation. This review intends to address these issues, using experimental research on Parkinson's disease (PD) as a paradigmatic example of the use of animal models to improve knowledge on a devastating human pathology. In particular, current rodent models of PD and their validity are reviewed and discussed, and methodologies that may ultimately reduce animal's suffering emphasized. Although procedures referring to with 3R principle can be traced in the literature reviewed, they are not considered yet an important part of the methodological information. The formal inclusion in scientific papers of a section devoted to 3Rs may increase knowledge and eventually adherence to this principle by scientists.
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Affiliation(s)
- Arianna Manciocco
- Section of Behavioral Neuroscience, Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Rome I-00161, Italy
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23
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Environmental enrichment mitigates the effects of basal forebrain lesions on cognitive flexibility. Neuroscience 2008; 154:444-53. [DOI: 10.1016/j.neuroscience.2008.03.069] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Revised: 03/25/2008] [Accepted: 03/25/2008] [Indexed: 11/20/2022]
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Tanimura Y, Yang MC, Lewis MH. Procedural learning and cognitive flexibility in a mouse model of restricted, repetitive behaviour. Behav Brain Res 2008; 189:250-6. [PMID: 18272239 DOI: 10.1016/j.bbr.2008.01.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Revised: 12/28/2007] [Accepted: 01/01/2008] [Indexed: 11/26/2022]
Abstract
Restricted, repetitive behaviours (e.g., stereotypies, compulsions, rituals) in neurodevelopmental disorders have been linked to alterations in cortico-basal ganglia circuitry. Cognitive processes mediated by this circuitry (e.g., procedural learning, executive function) are likely to be impaired in individuals exhibiting high rates of repetitive behaviour. To test this hypothesis, we assessed both procedural learning and cognitive flexibility (reversal learning) using a T-maze task in deer mice (Peromyscus maniculatus) exhibiting various rates of repetitive behaviour (vertical jumping and backward somersaulting). These mice exhibited high rates of stereotypy when reared in standard rodent cages, and such behaviour was significantly attenuated by housing them in larger more complex environments. Mice reared in complex environments exhibited significantly better procedural and reversal learning than standard caged mice. Thus, early experience associated with the prevention and attenuation of stereotypy was associated with better striatally mediated learning and cognitive flexibility. Stereotypy score was significantly correlated with the number of errors made in reversal learning, and interacted with housing condition to affect overall cognitive performance. Our findings support the applicability of the deer mouse model of spontaneous stereotypy to a wider range of restricted, repetitive behaviour (e.g., insistence on sameness) typical of neurodevelopmental disorders.
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Affiliation(s)
- Yoko Tanimura
- McKnight Brain Institute, Department of Psychiatry and Psychology, University of Florida, Gainesville, FL, USA
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25
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Dong S, Li C, Wu P, Tsien JZ, Hu Y. Environment enrichment rescues the neurodegenerative phenotypes in presenilins-deficient mice. Eur J Neurosci 2007; 26:101-12. [PMID: 17614943 DOI: 10.1111/j.1460-9568.2007.05641.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Presenilin (PS) 1 and 2 conditional double knockout (cDKO) mice show progressive memory dysfunction and forebrain degeneration. Gene expression profiling results revealed a strong activation of immunity and inflammation responses in the brains of 10-month-old cDKO mice. As environmental enrichment (EE) has been shown to be able to improve memory and induce neurogenesis of the brain, we assessed the effects of EE on the memory performance and the neurodegeneration in cDKO mice. We found that EE effectively enhanced memory and partially rescued the forebrain atrophy of the cDKO mice. Our results suggest that immunity and inflammation could play important roles in the neurodegeneration of cDKO mice. Furthermore, the beneficial effects of EE may be associated with the inhibition of the expression of immunity and inflammation-related genes in the brain.
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Affiliation(s)
- Suzhen Dong
- Key Laboratory of Brain Functional Genomics, MOE&STCSM, Shanghai Institute of Brain Functional Genomics, East China Normal University, Shanghai, China 200062
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26
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Pereira LO, Arteni NS, Petersen RC, da Rocha AP, Achaval M, Netto CA. Effects of daily environmental enrichment on memory deficits and brain injury following neonatal hypoxia-ischemia in the rat. Neurobiol Learn Mem 2006; 87:101-8. [PMID: 16931063 DOI: 10.1016/j.nlm.2006.07.003] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Revised: 07/09/2006] [Accepted: 07/10/2006] [Indexed: 01/17/2023]
Abstract
Environmental enrichment (EE) results in improved learning and spatial memory, as well as attenuates morphological changes resulting from cerebral ischemia in adult animals. This study examined the effects of daily EE on memory deficits in the water maze and cerebral damage, assessed in the hippocampus and cerebral cortex, caused by neonatal hypoxia-ischemia. Male Wistar rats in the 7th postnatal day were submitted to the Levine-Rice model of neonatal hypoxia-ischemia (HI), comprising permanent occlusion of the right common carotid artery and a period of hypoxia (90 min, 8%O(2)-92%N(2)). Starting two weeks after the HI event, animals were stimulated by the enriched environment (1h/day for 9 weeks); subsequent to the stimulation, performance of animals in the water maze was assessed. HI resulted in spatial reference and working memory impairments that were completely reversed by EE. Following the behavioral study, animals were killed and the hippocampal volume and cortical area were estimated. There was a significant reduction of both hippocampal volume and cortical area, ipsilateral to arterial occlusion, in HI animals; environmental stimulation had no effect on these morphological measurements. Presented data indicate that stimulation by the daily environmental enrichment recovers spatial memory deficits caused by neonatal hypoxia-ischemia without affecting tissue atrophy in either hippocampus or cortex.
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Affiliation(s)
- Lenir Orlandi Pereira
- Programa de Pós-graduação em Neurociências, ICBS, Universidade Federal do Rio Grande do Sul, Brazil
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27
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Barbelivien A, Herbeaux K, Oberling P, Kelche C, Galani R, Majchrzak M. Environmental enrichment increases responding to contextual cues but decreases overall conditioned fear in the rat. Behav Brain Res 2006; 169:231-8. [PMID: 16473418 DOI: 10.1016/j.bbr.2006.01.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Revised: 01/05/2006] [Accepted: 01/12/2006] [Indexed: 11/22/2022]
Abstract
This study aimed at investigating the effects of environmental enrichment on various aspects of contextual processing in adult female rats. In experiment 1, simple conditioning was studied using either a training procedure allowing overshadowing of the contextual cues by signalling footshock with a discrete tone or a training procedure allowing a reduction of this overshadowing by explicitly unpairing the footshock and the tone. In experiment 2, contextual discrimination and contextual occasion-setting were assessed. Rats were daily exposed to two different contexts. In one context, a footshock was delivered 30s after the offset of a tone, whereas in the other context the same tone was presented alone. Experiment 3 examined familiarization to a new context. Experiment 1 showed that environmental enrichment reduced the overshadowing of contextual cues by the tone and also reduced freezing to the more predictive cue according to the training procedure used. Experiment 2 showed that environmental enrichment increased the ability of rats to discriminate two contexts. Experiment 3 showed that enriched rats familiarized faster to a new context than standard rats. Taken together, these results suggest that environmental enrichment in adult rats enhances learning about contextual cues and reduces overall fear associated with aversive events.
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Affiliation(s)
- A Barbelivien
- Laboratoire de Neurosciences Comportementales et Cognitives, FRE 2855, Université Louis Pasteur, CNRS, IFR 37 des Neurosciences, Strasbourg, France
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28
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Jankowsky JL, Melnikova T, Fadale DJ, Xu GM, Slunt HH, Gonzales V, Younkin LH, Younkin SG, Borchelt DR, Savonenko AV. Environmental enrichment mitigates cognitive deficits in a mouse model of Alzheimer's disease. J Neurosci 2006; 25:5217-24. [PMID: 15917461 PMCID: PMC4440804 DOI: 10.1523/jneurosci.5080-04.2005] [Citation(s) in RCA: 375] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Epidemiological studies suggest that individuals with greater education or more cognitively demanding occupations have diminished risk of developing dementia. We wanted to test whether this effect could be recapitulated in rodents using environmental enrichment, a paradigm well documented to attenuate behavioral deficits induced by various pathological insults. Here, we demonstrate that learning and memory deficits observed in a transgenic mouse model of Alzheimer's disease can be ameliorated by enrichment. Female transgenic mice overexpressing amyloid precursor protein and/or presenilin-1 and nontransgenic controls were placed into enriched or standard cages at 2 months of age and tested for cognitive behavior after 6 months of differential housing. Enrichment significantly improved performance of all genotypes in the radial water maze and in the classic and repeated-reversal versions of the Morris water maze. However, enrichment did not benefit all genotypes equally. Mice overproducing amyloid-beta (Abeta), particularly those with amyloid deposits, showed weaker memory for the platform location in the classic Morris water maze and learned new platform positions in the repeated-reversals task less quickly than their nontransgenic cagemates. Nonetheless, enrichment normalized the performance of Abeta-overproducing mice to the level of standard-housed nontransgenic mice. Moreover, this functional preservation occurred despite increased neuritic plaque burden in the hippocampus of double-transgenic animals and elevated steady-state Abeta levels, because both endogenous and transgene-derived Abeta are increased in enriched animals. These results demonstrate that the generation of Abeta in vivo and its impact on the function of the nervous system can be strongly modulated by environmental factors.
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Affiliation(s)
- Joanna L Jankowsky
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
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Leggio MG, Mandolesi L, Federico F, Spirito F, Ricci B, Gelfo F, Petrosini L. Environmental enrichment promotes improved spatial abilities and enhanced dendritic growth in the rat. Behav Brain Res 2005; 163:78-90. [PMID: 15913801 DOI: 10.1016/j.bbr.2005.04.009] [Citation(s) in RCA: 344] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2005] [Revised: 04/12/2005] [Accepted: 04/14/2005] [Indexed: 11/22/2022]
Abstract
An enriched environment consists of a combination of enhanced social relations, physical exercise and interactions with non-social stimuli that leads to behavioral and neuronal modifications. In the present study, we analyzed the behavioral effects of environmental complexity on different facets of spatial function, and we assessed dendritic arborisation and spine density in a cortical area mainly involved in the spatial learning, as the parietal cortex. Wistar rat pups (21 days old) were housed in enriched conditions (10 animals in a large cage with toys and a running wheel), or standard condition (two animals in a standard cage, without objects). At the age of 3 months, both groups were tested in the radial maze task and Morris water maze (MWM). Morphological analyses on layer-III pyramidal neurons of parietal cortex were performed in selected animals belonging to both experimental groups. In the radial maze task, enriched animals exhibited high performance levels, by exploiting procedural competencies and working memory abilities. Furthermore, when the requirements of the context changed, they promptly reorganized their strategies by shifting from prevalently using spatial procedures to applying mnesic competencies. In the Morris water maze, enriched animals more quickly acquired tuned navigational strategies. Environmental enrichment provoked increased dendritic arborisation as well as increased density of dendritic spines in layer-III parietal pyramidal neurons.
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Affiliation(s)
- Maria Giuseppa Leggio
- Department of Psychology, University of Rome La Sapienza, Via dei Marsi 78, 00185 Rome, Italy.
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Bourgeon S, Xerri C, Coq JO. Abilities in tactile discrimination of textures in adult rats exposed to enriched or impoverished environments. Behav Brain Res 2004; 153:217-31. [PMID: 15219723 DOI: 10.1016/j.bbr.2003.12.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2003] [Revised: 11/28/2003] [Accepted: 12/02/2003] [Indexed: 11/23/2022]
Abstract
In previous studies, we have shown that housing in enriched environment for about 3 months after weaning improved the topographic organization and decreased the size of the receptive fields (RFs) located on the glabrous skin surfaces in the forepaw maps of the primary somatosensory cortex (SI) in rats [Exp. Brain Res. 121 (1998) 191]. In contrast, housing in impoverished environment induced a degradation of the SI forepaw representation, characterized by topographic disruptions, a reduction of the cutaneous forepaw area and an enlargement of the glabrous RFs [Exp. Brain Res. 129 (1999) 518]. Based on these two studies, we postulated that these representational alterations could underlie changes in haptic perception. Therefore, the present study was aimed at determining the influence of housing conditions on the rat's abilities in tactile texture discrimination. After a 2-month exposure to enriched or impoverished environments, rats were trained to perform a discrimination task during locomotion on floorboards of different roughness. At the end of every daily behavioral session, rats were replaced in their respective housing environment. Rats had to discriminate homogeneous (low roughness) from heterogeneous floorboards (combination of two different roughness levels). To determine the maximum performance in texture discrimination, the roughness contrast of the heterogeneous texture was gradually reduced, so that homogeneous and heterogeneous floorboards became harder to differentiate. We found that the enriched rats learned the first steps of the behavioral task faster than the impoverished rats, whereas both groups exhibited similar performances in texture discrimination. An individual "predilection" for either homogeneous or heterogeneous floorboards, presumably reflecting a behavioral strategy, seemed to account for the absence of differences in haptic discrimination between groups. The sensory experience depending on the rewarded texture discrimination task seems to have a greater influence on individual texture discrimination abilities than the sensorimotor experience related to housing conditions.
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Affiliation(s)
- Stéphanie Bourgeon
- UMR 6149 Neurobiologie Intégrative et Adaptative, Université de Provence-CNRS, Marseille, France
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31
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Will B, Galani R, Kelche C, Rosenzweig MR. Recovery from brain injury in animals: relative efficacy of environmental enrichment, physical exercise or formal training (1990-2002). Prog Neurobiol 2004; 72:167-82. [PMID: 15130708 DOI: 10.1016/j.pneurobio.2004.03.001] [Citation(s) in RCA: 261] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2003] [Accepted: 02/25/2004] [Indexed: 11/19/2022]
Abstract
In the 1960s, it was shown for the first time that enriched housing enhances functional recovery after brain damage. During the 1970s and 1980s, many findings similar to this initial one have been reported, enlarging greatly its generality. Over the last 13 years, many different kinds of brain damage were modelled in animals or even directly studied in humans. Overall, these recent studies corroborated earlier findings, although occasional exceptions were reported. Other critical data, obtained mainly in intact animals, showed that enriched housing increases neurogenesis in the adult hippocampus. Recent evidence that this neurogenesis is involved in hippocampal-dependent learning supports the original interpretation of the enrichment effects as being the result of an accumulation of informal learning experiences (e.g., [. Heredity, environment, brain biochemistry, and learning. In: Current Trends in Psychological Theory. University of Pittsburgh Press, Pittsburgh, pp. 87-110;. Brain changes in response to experience. Sci. Am. 226, 22-29]). Other components of enriched environment, such as physical exercise, may have additive effects with those of training. The comparison of the relative effectiveness of enriched experience, of physical exercise and of training on structural and/or functional assessments of recovery, shows that training/learning is generally more effective than physical exercise and that enriched experience is a more potent therapy than either of these two other treatments. The combination of enriched experience with some other neurosurgical and/or neuropharmacological treatments may further improve its therapeutic effectiveness. Finally, other recent reports emphasize that the treatment parameters may be changed in order to approximate clinical/rehabilitation conditions and, nevertheless, remain effective.
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Affiliation(s)
- Bruno Will
- Laboratoire de Neurosciences Comportementales et Cognitives, Institut Fédératif des Neurosciences, Université Louis Pasteur, UMR 7521, CNRS, Strasbourg, France.
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Hoffman JR, Donato A, Robbins SJ. Ginkgo biloba promotes short-term retention of spatial memory in rats. Pharmacol Biochem Behav 2004; 77:533-9. [PMID: 15006464 DOI: 10.1016/j.pbb.2003.12.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2003] [Revised: 12/09/2003] [Accepted: 12/10/2003] [Indexed: 11/23/2022]
Abstract
This study examines possible interactions between exposure to Ginkgo biloba extract and enriched environments on the acquisition and retention of spatial learning following massed and spaced trials. After 4 weeks of exposure to either ginkgo or vehicle, 8-week-old rats were tested using a Morris Water Maze in either massed or spaced trials. While ginkgo did not have an effect on maze acquisition or long-term retention, it did promote short-term retention of spatial memory. Following reversal training, ginkgo promoted short-term retention for two groups but impaired retention for a third. These results suggest that ginkgo has powerful effects on short-term retention that vary with training conditions.
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Affiliation(s)
- John R Hoffman
- Department of Biology, Arcadia University, 450 S. Easton Road, Glenside, PA 19038 USA.
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Frick KM, Fernandez SM. Enrichment enhances spatial memory and increases synaptophysin levels in aged female mice. Neurobiol Aging 2003; 24:615-26. [PMID: 12714119 DOI: 10.1016/s0197-4580(02)00138-0] [Citation(s) in RCA: 230] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The present study tested whether environmental enrichment can reduce age-related spatial reference memory deficits and alter synaptic protein levels in aged female mice. Female C57BL/6 mice, (4 or 27-28 months), were tested in spatial and cued Morris water maze tasks. Prior to (14 days) and during testing, a subset of aged females was exposed to rodent toys and running wheels for 3h per day. The remaining aged females were group housed but were not exposed to enriching objects. At the conclusion of testing, levels of the presynaptic protein synaptophysin were measured in hippocampus and frontoparietal cortex. Enrichment improved spatial memory acquisition; relative to young controls, aged enriched females performed similarly, whereas aged control females were impaired. Enrichment also accelerated the development of a spatial bias in spatial probe trials. In contrast, the cued task was not significantly affected by enrichment. Hippocampal and cortical synaptophysin levels were increased in aged enriched females relative to young and aged controls. These data suggest that environmental enrichment can be a potent cognitive enhancer for aged females and suggests a potential neurobiological mechanism of this effect.
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Affiliation(s)
- Karyn M Frick
- Department of Psychology, Yale University, New Haven, CT 06520, USA.
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Frick KM, Stearns NA, Pan JY, Berger-Sweeney J. Effects of environmental enrichment on spatial memory and neurochemistry in middle-aged mice. Learn Mem 2003; 10:187-98. [PMID: 12773583 PMCID: PMC202309 DOI: 10.1101/lm.50703] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2002] [Accepted: 02/19/2003] [Indexed: 11/24/2022]
Abstract
The present study compared the effects of environmental enrichment on spatial memory, glutamic acid decarboxylase (GAD) activity, and synaptophysin levels in middle-aged male and female mice. Prior to testing, a subset of 18-month-old male and female C57BL/6 mice was housed with two to three toys and a running wheel in the home cage for up to 29 d. Adult mice (7 mo) of both sexes and the remaining middle-aged mice were group (social) housed, but not exposed to enriching objects. After the enrichment period, all mice were tested in a 1-day version of the Morris water maze, in which both spatial and nonspatial memory were assessed. Immediately after testing, the hippocampus and frontoparietal cortex were dissected, and GAD activity and synaptophysin levels were measured. Environmental enrichment reduced the age-related impairment in spatial acquisition and retention; relative to adult social controls, middle-aged enriched mice were unimpaired, whereas middle-aged social controls were impaired. This reduction was similar in middle-aged males and females. Enrichment did not affect cued memory in either sex. Although hippocampal GAD activity was increased by enrichment in males, all other neurochemical measurements were unaffected by enrichment or aging in either sex. These data suggest that environmental enrichment initiated at middle age can reduce age-related impairments in spatial memory in males and females, although the underlying neurobiological mechanisms of this effect remain unknown.
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Affiliation(s)
- Karyn M Frick
- Department of Psychology, Yale University, New Haven, Connecticut 06520, USA
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Martínez-Cué C, Baamonde C, Lumbreras M, Paz J, Davisson MT, Schmidt C, Dierssen M, Flórez J. Differential effects of environmental enrichment on behavior and learning of male and female Ts65Dn mice, a model for Down syndrome. Behav Brain Res 2002; 134:185-200. [PMID: 12191805 DOI: 10.1016/s0166-4328(02)00026-8] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We have assessed the effects of enriched environment (EE) upon behavioral and cognitive performances of partially trisomic Ts65Dn (TS) mice and their control (CO) littermates. Enriched environment was applied to pups for 7 weeks after weaning. Circadian spontaneous activity (actimetry), exploratory behavior (hole board), activity in the open field and spatial memory (Morris Water Maze, repeated acquisition and cued paradigms) were analyzed in 86 female and 75 male mice, starting 15 days after completing enrichment. For each gender, mice were distributed in non-enriched and enriched control and trisomic groups. Enriched environment reduced in trisomic females and enhanced in trisomic males' circadian activity. Exploratory behavior was increased by enrichment in all groups, regardless of gender or presence of trisomy. In the Morris Water Maze, a significant improvement of the spatial memory was observed in enriched-control females, but not in enriched-control male mice, as assessed by distances traveled. Performances in the four groups of control animals were also consistently and significantly better than those of matching trisomic mice. In the acquisition trials, enrichment improved performance in trisomic female animals, but deteriorated in trisomic male mice. In all groups, changes in escape latencies and distances induced by enrichment were accounted for by changes in the total time spent in the periphery of the pool, indicating changes in learning strategy. Working memory was the function more affected by enrichment. It is concluded that enriched environment induces behavioral and learning changes in trisomic mice, although gender plays a significant modulatory role.
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Affiliation(s)
- Carmen Martínez-Cué
- Department of Physiology and Pharmacology, Laboratory of Developmental Neurobiology, University of Cantabria, Avenida Herrera Oria, s/n 39011 Santander, Spain
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The social transmission of feather pecking in laying hens: effects of environment and age. Appl Anim Behav Sci 2002. [DOI: 10.1016/s0168-1591(01)00182-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Woodcock EA, Richardson R. Effects of multisensory environmental stimulation on contextual conditioning in the developing rat. Neurobiol Learn Mem 2000; 74:89-104. [PMID: 10933896 DOI: 10.1006/nlme.1999.3949] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of increased exposure to multisensory stimulation during development on conditioned freezing to contextual cues in preweanling Sprague-Dawley rats was examined. Rats given increased environmental stimulation exhibited long-term contextual conditioning at a younger age than rats that did not receive such stimulation when there was either low or moderate levels of conditioning (Experiments 1 and 2). These differences in contextual conditioning were not a result of the stimulated rats reacting differently to shock (Experiment 4) or merely freezing more than the nonstimulated rats in all situations (Experiment 3). The role of the glucocorticoid system in the enhanced contextual learning of stimulated preweanling rats and the advantages of the contextual conditioning procedure for studying the effects of environmental stimulation are discussed.
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Affiliation(s)
- E A Woodcock
- University of New South Wales, Sydney, New South Wales 2052, Australia
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