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Popović N, Baño-Otalora B, Rol MÁ, Venero C, Madrid JA, Popović M. Effects of long-term individual housing of middle-aged female Octodon degus on spatial learning and memory in the Barnes maze task. Front Behav Neurosci 2023; 17:1221090. [PMID: 37600762 PMCID: PMC10435294 DOI: 10.3389/fnbeh.2023.1221090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Accepted: 07/18/2023] [Indexed: 08/22/2023] Open
Abstract
Introduction Prolonged social isolation is a form of passive chronic stress that has consequences on human and animal behavior. The present study was undertaken to elucidate whether the long-term isolation would precipitate age-related changes in anxiety and spatial learning and memory in degus. Methods We investigated the effects of long-term social isolation on anxiety levels in the light-dark test, and spatial orientation abilities in the Barnes maze. Middle-aged female Octodon degus were allocated to either group-housed (3 animals per cage) or individually-housed for 5 months. Results Under this experimental condition, there were no significant group differences in the anxiety level tested in the light-dark test and in the motivation to escape from the Barnes maze. There were no significant differences in cortisol levels between individually- and group-housed animals. On the last acquisition training day of spatial learning, individually- housed animals had a significantly higher number of correct responses and a smaller number of reference and working memory errors than the group-housed animals. In addition, isolated animals showed a tendency for reference and working memory impairment on the retention trial, while group-housed degus showed improvement in these parameters. Discussion and conclusion The present study indicates that prolonged social isolation during adulthood in female degus has a dual effect on spatial orientation. Specifically, it results in a significant improvement in acquisition skills but a slight impairment in memory retention. The obtained cognitive changes were not accompanied by modification in anxiety and cortisol levels.
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Affiliation(s)
- Natalija Popović
- Department of Human Anatomy and Psychobiology, Faculty of Medicine, University of Murcia, Murcia, Spain
- Biomedical Research Institute of Murcia, Virgen de la Arrixaca University Hospital, University of Murcia, Murcia, Spain
| | - Beatriz Baño-Otalora
- Chronobiology Lab, Department of Physiology, Faculty of Biology, University of Murcia, Mare Nostrum Campus, Instituto Universitario de Investigación en Envejecimiento, Murcia, Spain
| | - María Ángeles Rol
- Biomedical Research Institute of Murcia, Virgen de la Arrixaca University Hospital, University of Murcia, Murcia, Spain
- Chronobiology Lab, Department of Physiology, Faculty of Biology, University of Murcia, Mare Nostrum Campus, Instituto Universitario de Investigación en Envejecimiento, Murcia, Spain
- Ciber Fragilidad y Envejecimiento Saludable, Madrid, Spain
| | - César Venero
- Department of Psychobiology, Universidad Nacional de Educación a Distancia, Madrid, Spain
- Instituto Mixto de Investigación–Escuela Nacional de Sanidad, Madrid, Spain
| | - Juan Antonio Madrid
- Biomedical Research Institute of Murcia, Virgen de la Arrixaca University Hospital, University of Murcia, Murcia, Spain
- Chronobiology Lab, Department of Physiology, Faculty of Biology, University of Murcia, Mare Nostrum Campus, Instituto Universitario de Investigación en Envejecimiento, Murcia, Spain
- Ciber Fragilidad y Envejecimiento Saludable, Madrid, Spain
| | - Miroljub Popović
- Department of Human Anatomy and Psychobiology, Faculty of Medicine, University of Murcia, Murcia, Spain
- Biomedical Research Institute of Murcia, Virgen de la Arrixaca University Hospital, University of Murcia, Murcia, Spain
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Ukyo R, Shinohara A, Koshimoto C, Nagura-Kato GA, Ieiri S, Tsuzuki Y, Sakamoto SH. Long-term behavioral effects of social separation during early life in a social mammal, Octodon degus. Sci Rep 2023; 13:9518. [PMID: 37308511 DOI: 10.1038/s41598-023-36745-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 06/08/2023] [Indexed: 06/14/2023] Open
Abstract
Social separation is thought to induce a strong stress response in social juvenile mammals, but little is known about how this response might vary throughout the development. The present study examines the long-term effects of early-life stress (ELS) induced by social separation on individual behaviors later in life using the social and precocious species Octodon degus. Four experimental groups were established a positive control group of mothers and siblings from six litters comprised the socially housed (SH) group, while pups from seven litters were randomly assigned to three treatments: pups experiencing no separation (NS) treatment while their siblings did; repeated bouts of consecutive separation (CS); intermittent separation (IS). We analyzed the effects of separation treatment on the frequency and duration of freezing, rearing and grooming behaviors. ELS was correlated with higher hyperactivity, and hyperactivity increased with more frequent separation. However, the behavioral trend of the NS group changed to hyperactive in long-term observation. The findings suggest that the NS group was indirectly affected by ELS. In addition, suggesting ELS acts to converge an individual's behavioral tendencies in a certain direction.
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Affiliation(s)
- Rina Ukyo
- Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki, Miyazaki, Japan
| | - Akio Shinohara
- Division of Bio-Resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake-cho, Miyazaki-shi, Miyazaki, 889-1692, Japan
| | - Chihiro Koshimoto
- Division of Bio-Resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake-cho, Miyazaki-shi, Miyazaki, 889-1692, Japan
| | - Goro A Nagura-Kato
- Division of Bio-Resources, Department of Biotechnology, Frontier Science Research Center, University of Miyazaki, 5200 Kihara, Kiyotake-cho, Miyazaki-shi, Miyazaki, 889-1692, Japan
| | - Seiji Ieiri
- Faculty of Agriculture, University of Miyazaki, Miyazaki, 889-2192, Japan
| | - Yasuhiro Tsuzuki
- Faculty of Agriculture, University of Miyazaki, Miyazaki, 889-2192, Japan
| | - Shinsuke H Sakamoto
- Faculty of Agriculture, University of Miyazaki, Miyazaki, 889-2192, Japan.
- Center for Animal Disease Control, University of Miyazaki, Miyazaki, Japan.
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Dos Santos AS, Segabinazi E, de Almeida W, Faustino AM, Bronauth LP, Dos Santos TM, Ferreira FS, Wyse ATS, Marcuzzo S, Pereira LO. Resistance exercise was safe for the pregnancy and offspring's development and partially protected rats against early life stress-induced effects. Behav Brain Res 2023; 445:114362. [PMID: 36889464 DOI: 10.1016/j.bbr.2023.114362] [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: 04/26/2022] [Revised: 02/13/2023] [Accepted: 02/24/2023] [Indexed: 03/08/2023]
Abstract
Promising evidence points to gestational physical exercise as the key to preventing various disorders that affect the offspring neurodevelopment, but there are no studies showing the impact of resistance exercise on offspring health. Thus, the aim of this study was to investigate whether resistance exercise during pregnancy is able to prevent or to alleviate the possible deleterious effects on offspring, caused by early life-stress (ELS). Pregnant rats performed resistance exercise throughout the gestational period:they climbed a sloping ladder with a weight attached to their tail, 3 times a week. Male and female pups, on the day of birth (P0), were divided into 4 experimental groups: 1) rats of sedentary mothers (SED group); 2) rats of exercised mothers (EXE group); 3) rats of sedentary mothers and submitted to maternal separation (ELS group) and 4) rats of exercised mothers and submitted to MS (EXE + ELS group). From P1 to P10, pups from groups 3 and 4 were separated from their mothers for 3 h/day. Maternal behavior was assessed. From P30, behavioral tests were performed and on P38 the animals were euthanized and prefrontal cortex samples were collected. Oxidative stress and tissue damage analysis by Nissl staining were performed. Our results demonstrate that male rats are more susceptible to ELS than females, showing impulsive and hyperactive behavior similar to that seen in children with ADHD. This behavior was attenuated by the gestational resistance exercise. Our results demonstrate, for the first time, that resistance exercise performed during pregnancy seems to be safe for the pregnancy and offspring's neurodevelopment and are effective in preventing ELS-induced damage only in male rats. Interestingly, resistance exercise during pregnancy improved maternal care and it is reasonable to propose that this finding may be related to the protective role on the animals neurodevelopment, observed in our study.
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Affiliation(s)
- Adriana Souza Dos Santos
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Departamento de Ciências Morfológicas, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Ethiane Segabinazi
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Departamento de Ciências Morfológicas, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Wellington de Almeida
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Departamento de Ciências Morfológicas, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Aline Martins Faustino
- Departamento de Ciências Morfológicas, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Loise Peres Bronauth
- Departamento de Ciências Morfológicas, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Tiago Marcon Dos Santos
- Departamento de Bioquímica, Programa de Pós-Graduação em Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Fernanda Silva Ferreira
- Departamento de Bioquímica, Programa de Pós-Graduação em Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Angela T S Wyse
- Departamento de Bioquímica, Programa de Pós-Graduação em Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Simone Marcuzzo
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Departamento de Ciências Morfológicas, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Lenir Orlandi Pereira
- Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Departamento de Ciências Morfológicas, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Hasegawa R, Saito-Nakaya K, Gu L, Kanazawa M, Fukudo S. Maternal separation and TNBS-induced gut inflammation synergistically alter the sexually differentiated stress response in rats. Biopsychosoc Med 2023; 17:7. [PMID: 36841797 PMCID: PMC9960214 DOI: 10.1186/s13030-022-00258-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 12/12/2022] [Indexed: 02/27/2023] Open
Abstract
BACKGROUND Neonatal maternal separation (MS) has been used to model long-lasting changes in behavior caused by neuroplastic changes associated with exposure to early-life stress. Earlier studies showed that transient gut inflammation can influence the development of irritable bowel syndrome (IBS). A prevailing paradigm of the etiology of IBS is that transient noxious events lead to long-lasting sensitization of the neural pain circuit, despite complete resolution of the initiating event. This study characterizes the changes in behaviors and neuroendocrine parameters after MS and early-phase trinitrobenzene sulfonic acid (TNBS)-induced colitis. We tested the hypothesis that MS and gut inflammation synergistically induce (1) hyperactivity in male rats and anxiety-like behaviors in female rats and (2) activation of the HPA axis in female rats and deactivation of the HPA axis in male rats after colorectal distention (CRD). METHODS Male and female rat pups were separated from their dams for 180 min daily from postnatal day (PND) 2 to PND 14 (MS). Early-phase colitis was induced by colorectal administration with TNBS on PND 8. The elevated plus-maze test was performed at 7 weeks. Tonic CRD was performed at 60 mmHg for 15 min at 8 weeks. Plasma ACTH and serum corticosterone were measured at baseline or after the CRD. Analysis of variance was performed for comparison among controls, TNBS, MS, and MS + TNBS. RESULTS In male rats, the time spent in open arms significantly differed among the groups (p < 0.005). The time spent in open arms in male MS + TNBS rats was significantly higher than that of controls (p < 0.009) or TNBS rats (p < 0.031, post hoc test). Female rats showed no difference in the time spent in open arms among the groups. MS and gut inflammation induced an increase in plasma ACTH in female rats but not in male rats at baseline. CONCLUSIONS These findings suggest that MS and gut inflammation synergistically induce hyperactive behavior or exaggerated hypothalamic-pituitary-adrenal axis function depending on sex.
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Affiliation(s)
- Ryoko Hasegawa
- grid.69566.3a0000 0001 2248 6943Department of Behavioral Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo, Aoba, Sendai 980-8575 Japan
| | - Kumi Saito-Nakaya
- grid.69566.3a0000 0001 2248 6943Department of Behavioral Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo, Aoba, Sendai 980-8575 Japan ,grid.69566.3a0000 0001 2248 6943Tohoku Medical Megabank Organization, Tohoku University, 2-1 Seiryo, Aoba, Sendai 980-8575 Japan
| | - Li Gu
- grid.69566.3a0000 0001 2248 6943Department of Behavioral Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo, Aoba, Sendai 980-8575 Japan ,grid.410560.60000 0004 1760 3078Department of Psychology, School of Humanities and Management, Guangdong Medical University, Dongguan, China
| | - Motoyori Kanazawa
- grid.69566.3a0000 0001 2248 6943Department of Behavioral Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo, Aoba, Sendai 980-8575 Japan
| | - Shin Fukudo
- Department of Behavioral Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo, Aoba, Sendai, 980-8575, Japan.
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5
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Bouchet H, Lemasson A, Collier K, Marker L, Schmidt-Küntzel A, Johnston B, Hausberger M. Early life experience and sex influence acoustic repertoire use in wild-born, but hand-reared, captive cheetahs (Acinonyx jubatus). Dev Psychobiol 2022; 64:e22309. [PMID: 36282750 DOI: 10.1002/dev.22309] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 05/30/2022] [Accepted: 06/03/2022] [Indexed: 01/27/2023]
Abstract
Early deprivation of adult influence is known to have long-lasting effects on social abilities, notably communication skills, as adults play a key role in guiding and regulating the behavior of youngsters, including acoustic repertoire use in species in which vocal production is not learned. Cheetahs grow up alongside their mother for 18 months, thus maternal influences on the development of social skills are likely to be crucial. Here, we investigated the impact of early maternal deprivation on vocal production and use in 12 wild-born cheetahs, rescued and subsequently hand-reared either at an early (less than 2 months) or a later stage of development. We could distinguish 16 sound types, produced mostly singly but sometimes in repeated or multitype sound sequences. The repertoire of these cheetahs did not differ fundamentally from that described in other studies on adult cheetahs, but statistical analyses revealed a concurrent effect of both early experience and sex on repertoire use. More specifically, early-reared males were characterized by a high proportion of Purr, Meow, and Stutter; early-reared females Mew, Growl, Hoot, Sneeze, and Hiss; late-reared males Meow, Mew, Growl, and Howl; and late-reared females mostly Meow. Our study demonstrates therefore the long-term effects of maternal deprivation on communication skills in a limited-vocal learner and its differential effect according to sex, in line with known social differences and potential differential maternal investment. More generally, it emphasizes the critical importance to consider the past history of the subjects (e.g., captive/wild-born, mother/hand-reared, early/late-mother-deprived, etc.) when studying social behavior, notably acoustic communication.
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Affiliation(s)
- Hélène Bouchet
- CNRS, EthoS (Ethologie animale et humaine), Univ Rennes, Normandie Univ, UMR 6552, Paimpont, France
| | - Alban Lemasson
- CNRS, EthoS (Ethologie animale et humaine), Univ Rennes, Normandie Univ, UMR 6552, Rennes, France.,Institut Universitaire de France, Paris, France
| | - Katie Collier
- CNRS, EthoS (Ethologie animale et humaine), Univ Rennes, Normandie Univ, UMR 6552, Paimpont, France
| | | | | | | | - Martine Hausberger
- CNRS, EthoS (Ethologie animale et humaine), Univ Rennes, Normandie Univ, UMR 6552, Paimpont, France
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6
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Gall AJ, Shuboni-Mulligan DD. Keep Your Mask On: The Benefits of Masking for Behavior and the Contributions of Aging and Disease on Dysfunctional Masking Pathways. Front Neurosci 2022; 16:911153. [PMID: 36017187 PMCID: PMC9395722 DOI: 10.3389/fnins.2022.911153] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
Environmental cues (e.g., light-dark cycle) have an immediate and direct effect on behavior, but these cues are also capable of “masking” the expression of the circadian pacemaker, depending on the type of cue presented, the time-of-day when they are presented, and the temporal niche of the organism. Masking is capable of complementing entrainment, the process by which an organism is synchronized to environmental cues, if the cues are presented at an expected or predictable time-of-day, but masking can also disrupt entrainment if the cues are presented at an inappropriate time-of-day. Therefore, masking is independent of but complementary to the biological circadian pacemaker that resides within the brain (i.e., suprachiasmatic nucleus) when exogenous stimuli are presented at predictable times of day. Importantly, environmental cues are capable of either inducing sleep or wakefulness depending on the organism’s temporal niche; therefore, the same presentation of a stimulus can affect behavior quite differently in diurnal vs. nocturnal organisms. There is a growing literature examining the neural mechanisms underlying masking behavior based on the temporal niche of the organism. However, the importance of these mechanisms in governing the daily behaviors of mammals and the possible implications on human health have been gravely overlooked even as modern society enables the manipulation of these environmental cues. Recent publications have demonstrated that the effects of masking weakens significantly with old age resulting in deleterious effects on many behaviors, including sleep and wakefulness. This review will clearly outline the history, definition, and importance of masking, the environmental cues that induce the behavior, the neural mechanisms that drive them, and the possible implications for human health and medicine. New insights about how masking is affected by intrinsically photosensitive retinal ganglion cells, temporal niche, and age will be discussed as each relates to human health. The overarching goals of this review include highlighting the importance of masking in the expression of daily rhythms, elucidating the impact of aging, discussing the relationship between dysfunctional masking behavior and the development of sleep-related disorders, and considering the use of masking as a non-invasive treatment to help treat humans suffering from sleep-related disorders.
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Affiliation(s)
- Andrew J. Gall
- Department of Psychology and Neuroscience Program, Hope College, Holland, MI, United States
- *Correspondence: Andrew J. Gall,
| | - Dorela D. Shuboni-Mulligan
- Neuro-Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
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7
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Filippa M, Monaci MG, Spagnuolo C, Serravalle P, Daniele R, Grandjean D. Maternal speech decreases pain scores and increases oxytocin levels in preterm infants during painful procedures. Sci Rep 2021; 11:17301. [PMID: 34453088 PMCID: PMC8397753 DOI: 10.1038/s41598-021-96840-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 08/11/2021] [Indexed: 12/28/2022] Open
Abstract
Preterm infants undergo early separation from parents and are exposed to frequent painful clinical procedures, with resultant short- and long-term effects on their neurodevelopment. We aimed to establish whether the mother's voice could provide an effective and safe analgesia for preterm infants and whether endogenous oxytocin (OXT) could be linked to pain modulation. Twenty preterm infants were exposed to three conditions-mother's live voice (speaking or singing) and standard care-in random order during a painful procedure. OXT levels (pg/mL) in saliva and plasma cortisol levels were quantified, and the Premature Infant Pain Profile (PIPP) was blindly coded by trained psychologists. During the mother's live voice, PIPP scores significantly decreased, with a concomitant increase in OXT levels over baseline. The effect on pain perception was marginally significant for singing. No effects on cortisol levels were found. The mother's live voice modulated preterm infants' pain indicators. Endogenous OXT released during vocal contact is a promising protective mechanism during early painful interventions in at-risk populations.
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Affiliation(s)
- Manuela Filippa
- Swiss Center of Affective Sciences, Faculty of Psychology and Educational Sciences, University of Geneva, Geneva, Switzerland.
- Department of Social Sciences, University of Valle D'Aosta, Aosta, Italy.
| | | | | | | | - Roberta Daniele
- Department of Clinical Pathology, Parini Hospital, Aosta, Italy
| | - Didier Grandjean
- Swiss Center of Affective Sciences, Faculty of Psychology and Educational Sciences, University of Geneva, Geneva, Switzerland
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8
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Watanabe S, Scheich H, Braun K, Shinozuka K. Visual snake aversion in Octodon degus and C57BL/6 mice. Anim Cogn 2021; 25:33-41. [PMID: 34156548 DOI: 10.1007/s10071-021-01527-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 04/26/2021] [Accepted: 06/10/2021] [Indexed: 11/29/2022]
Abstract
Phobia against spiders or snakes is common in humans, and similar phobia-like behaviors have been observed in non-human animals. Visual images of snakes elicit phobia in humans, but sensory modalities that cause snake aversion in non-human animals are not well examined. In this study, we examined visually induced snake aversion in two rodent species. Using a three-compartment experimental chamber, reactions to images of snakes were compared between the diurnal precocious rodent Octodon degus and nocturnal laboratory mice. The snakes whose images were presented do not live in the original habitats of degus or mice. Snake aversion was assessed by presenting snake vs. no-image, snake vs. flower, snake vs. degu, and snake vs. mouse images. The time spent in a compartment with the snake image and with the non-snake images were measured. Degus avoided images of snakes in every tests. In contrast, mice did not display snake aversion. Degus are diurnal animals, i.e., visual information is important for their survival. Since mice are nocturnal, visual information is less important for survival. Such behavioral differences in the two species may explain the difference in visually induced aversion to snakes. A principal component analysis of the stimulus images suggests that elementary cues, such as color, do not explain the differences in the species' aversion to snakes. Finally, snake aversion in degus suggests that aversion is innate, since the animals were born and raised in a laboratory.
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Affiliation(s)
| | - Henning Scheich
- Professor Emeritus, Leibniz Institute of Neurobiology, Magdeburg, Germany.,Center for Behavioral and Brain Science (CBBS), Magdeburg, Germany
| | - Katharina Braun
- Department of Zoology/Developmental Neurobiology, Faculty of Natural Sciences, Otto Von Guericke University, Magdeburg, Germany.,Center for Behavioral and Brain Science (CBBS), Magdeburg, Germany
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9
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Rivera DS, Lindsay CB, Oliva CA, Bozinovic F, Inestrosa NC. "Live together, die alone": The effect of re-socialization on behavioural performance and social-affective brain-related proteins after a long-term chronic social isolation stress. Neurobiol Stress 2021; 14:100289. [PMID: 33426200 PMCID: PMC7785960 DOI: 10.1016/j.ynstr.2020.100289] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 12/18/2020] [Accepted: 12/21/2020] [Indexed: 01/02/2023] Open
Abstract
Loneliness affects group-living mammals triggering a cascade of stress-dependent physiological disorders. Indeed, social isolation stress is a major risk factor for several neuropsychiatric disorders including anxiety and depression. Furthermore, social isolation has a negative impact on health and fitness. However, the neurobiological consequences of long-term chronic social isolation stress (LTCSIS) manifested during the adulthood of affected individuals are not fully understood. Our study assessed the impact of LTCSIS and social buffering (re-socialization) on the behavioural performance and social-affective brain-related proteins in diurnal, social, and long-lived Octodon degus (degus). Thereby, anxiety-like and social behaviour, and social recognition memory were assessed in male and female animals subjected to a variety of stress-inducing treatments applied from post-natal and post-weaning until their adulthood. Additionally, we evaluated the relationship among LTCSIS, Oxytocin levels (OXT), and OXT-Ca2+-signalling proteins in the hypothalamus, the hippocampus, and the prefrontal cortex. Our findings suggest that LTCSIS induces anxiety like-behaviour and impairs social novelty preference whereas sociability is unaffected. On the other hand, re-socialization can revert both isolation-induced anxiety and social memory impairment. However, OXT and its signalling remained reduced in the abovementioned brain areas, suggesting that the observed changes in OXT-Ca2+ pathway proteins were permanent in male and female degus. Based on these findings, we conclude degus experience social stress differently, suggesting the existence of sex-related mechanisms to cope with specific adaptive challenges.
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Affiliation(s)
- Daniela S. Rivera
- GEMA Center for Genomics, Ecology & Environment, Facultad de Estudios Interdisciplinarios, Universidad Mayor, Santiago, Chile
| | - Carolina B. Lindsay
- Center of Aging and Regeneration UC (CARE-UC), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carolina A. Oliva
- Center of Aging and Regeneration UC (CARE-UC), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Francisco Bozinovic
- Center for Applied Ecology and Sustainability (CAPES), Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nibaldo C. Inestrosa
- Center of Aging and Regeneration UC (CARE-UC), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
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10
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van Groen T, Kadish I, Popović N, Caballero Bleda M, Baño-Otalora B, Rol MA, Madrid JA, Popović M. Widespread Doublecortin Expression in the Cerebral Cortex of the Octodon degus. Front Neuroanat 2021; 15:656882. [PMID: 33994960 PMCID: PMC8116662 DOI: 10.3389/fnana.2021.656882] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Abstract
It has been demonstrated that in adulthood rodents show newly born neurons in the subgranular layer (SGL) of the dentate gyrus (DG), and in the subventricular zone (SVZ). The neurons generated in the SVZ migrate through the rostral migratory stream (RMS) to the olfactory bulb. One of the markers of newly generated neurons is doublecortin (DCX). The degu similarly shows significant numbers of DCX-labeled neurons in the SGL, SVZ, and RMS. Further, most of the nuclei of these DCX-expressing neurons are also labeled by proliferating nuclear antigen (PCNA) and Ki67. Finally, whereas in rats and mice DCX-labeled neurons are predominantly present in the SGL and SVZ, with only a few DCX neurons present in piriform cortex, the degu also shows significant numbers of DCX expressing neurons in areas outside of SVZ, DG, and PC. Many areas of neocortex in degu demonstrate DCX-labeled neurons in layer II, and most of these neurons are found in the limbic cortices. The DCX-labeled cells do not stain with NeuN, indicating they are immature neurons.
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Affiliation(s)
- Thomas van Groen
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Inga Kadish
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Natalija Popović
- Department of Human Anatomy and Psychobiology, Faculty of Medicine, University of Murcia, Murcia, Spain.,Institute of Biomedical Research of Murcia, Virgen de la Arrixaca University Hospital, University of Murcia, Murcia, Spain.,CEIR Campus Mare Nostrum (CMN), University of Murcia, Murcia, Spain
| | - María Caballero Bleda
- Department of Human Anatomy and Psychobiology, Faculty of Medicine, University of Murcia, Murcia, Spain.,Institute of Biomedical Research of Murcia, Virgen de la Arrixaca University Hospital, University of Murcia, Murcia, Spain.,CEIR Campus Mare Nostrum (CMN), University of Murcia, Murcia, Spain
| | - Beatriz Baño-Otalora
- Division of Neuroscience and Experimental Psychology, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - María Angeles Rol
- Institute of Biomedical Research of Murcia, Virgen de la Arrixaca University Hospital, University of Murcia, Murcia, Spain.,CEIR Campus Mare Nostrum (CMN), University of Murcia, Murcia, Spain.,Chronobiology Laboratory, Department of Physiology, Faculty of Biology, University of Murcia, Murcia, Spain
| | - Juan Antonio Madrid
- Institute of Biomedical Research of Murcia, Virgen de la Arrixaca University Hospital, University of Murcia, Murcia, Spain.,CEIR Campus Mare Nostrum (CMN), University of Murcia, Murcia, Spain.,Chronobiology Laboratory, Department of Physiology, Faculty of Biology, University of Murcia, Murcia, Spain
| | - Miroljub Popović
- Department of Human Anatomy and Psychobiology, Faculty of Medicine, University of Murcia, Murcia, Spain.,Institute of Biomedical Research of Murcia, Virgen de la Arrixaca University Hospital, University of Murcia, Murcia, Spain.,CEIR Campus Mare Nostrum (CMN), University of Murcia, Murcia, Spain
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11
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Rivera DS, Lindsay CB, Oliva CA, Codocedo JF, Bozinovic F, Inestrosa NC. Effects of long-lasting social isolation and re-socialization on cognitive performance and brain activity: a longitudinal study in Octodon degus. Sci Rep 2020; 10:18315. [PMID: 33110163 PMCID: PMC7591540 DOI: 10.1038/s41598-020-75026-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/27/2020] [Indexed: 12/18/2022] Open
Abstract
Social isolation is considered a stressful situation that results in increased physiological reactivity to novel stimuli, altered behaviour, and impaired brain function. Here, we investigated the effects of long-term social isolation on working memory, spatial learning/memory, hippocampal synaptic transmission, and synaptic proteins in the brain of adult female and male Octodon degus. The strong similarity between degus and humans in social, metabolic, biochemical, and cognitive aspects, makes it a unique animal model that can be highly applicable for further social, emotional, cognitive, and aging studies. These animals were socially isolated from post-natal and post-weaning until adulthood. We also evaluated if re-socialization would be able to compensate for reactive stress responses in chronically stressed animals. We showed that long-term social isolation impaired the HPA axis negative feedback loop, which can be related to cognitive deficits observed in chronically stressed animals. Notably, re-socialization restored it. In addition, we measured physiological aspects of synaptic transmission, where chronically stressed males showed more efficient transmission but deficient plasticity, as the reverse was true on females. Finally, we analysed synaptic and canonical Wnt signalling proteins in the hypothalamus, hippocampus, and prefrontal cortex, finding both sex- and brain structure-dependent modulation, including transient and permanent changes dependent on stress treatment.
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Affiliation(s)
- Daniela S Rivera
- GEMA Center for Genomics, Ecology and Environment, Facultad de Estudios Interdisciplinarios, Universidad Mayor, Santiago, Chile.
| | - Carolina B Lindsay
- Center of Aging and Regeneration UC (CARE-UC), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carolina A Oliva
- Center of Aging and Regeneration UC (CARE-UC), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan Francisco Codocedo
- Center of Aging and Regeneration UC (CARE-UC), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Francisco Bozinovic
- Center for Applied Ecology and Sustainability (CAPES), Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nibaldo C Inestrosa
- Center of Aging and Regeneration UC (CARE-UC), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile. .,Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile.
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12
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Švara T, Gombač M, Poli A, Račnik J, Zadravec M. Spontaneous Tumors and Non-Neoplastic Proliferative Lesions in Pet Degus ( Octodon degus). Vet Sci 2020; 7:vetsci7010032. [PMID: 32183187 PMCID: PMC7158670 DOI: 10.3390/vetsci7010032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/05/2020] [Accepted: 03/11/2020] [Indexed: 02/05/2023] Open
Abstract
In recent years, degus (Octodon degus), rodents native to South America, have been becoming increasingly popular as pet animals. Data about neoplastic diseases in this species are still sparse and mainly limited to single-case reports. The aim of this study was to present neoplastic and non-neoplastic proliferative changes in 16/100 pet degus examined at the Veterinary Faculty University of Ljubljana from 2010 to 2015 and to describe the clinic-pathological features of these lesions. Twenty different lesions of the integumentary, musculoskeletal, genitourinary and gastrointestinal systems were diagnosed: amongst these were 13 malignant tumors, six benign tumors, and one non-neoplastic lesion. Cutaneous fibrosarcoma was the most common tumor (7/16 degus). It was detected more often in females (6/7 degus) and lesions were located mainly in hind limbs. The gastrointestinal tract was frequently affected, namely with two malignant neoplasms - an intestinal lymphoma and a mesenteric mesothelioma, four benign tumors - two biliary cystadenomas, an oral squamous papilloma and a hepatocellular adenoma, and a single non-neoplastic proliferative lesion. In one animal, two organic systems were involved in neoplastic lesions.
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Affiliation(s)
- Tanja Švara
- Institute of Pathology, Wild Animals, Fish and Bees, Veterinary Faculty, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (T.Š.); (M.G.)
| | - Mitja Gombač
- Institute of Pathology, Wild Animals, Fish and Bees, Veterinary Faculty, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (T.Š.); (M.G.)
| | - Alessandro Poli
- Department of Veterinary Science, University of Pisa, 56124 Pisa, Italy
- Correspondence:
| | - Jožko Račnik
- Clinic for Birds, Small mammals and Reptiles, Institute of Poultry, Birds, Small Mammals and Reptiles, Veterinary Faculty, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (J.R.); (M.Z.)
| | - Marko Zadravec
- Clinic for Birds, Small mammals and Reptiles, Institute of Poultry, Birds, Small Mammals and Reptiles, Veterinary Faculty, University of Ljubljana, SI-1000 Ljubljana, Slovenia; (J.R.); (M.Z.)
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13
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Influence of Pre-Weaning Social Isolation on Post-Weaning Emotion Tendency and Mother-Infant Interactions in Infant Octodon Degus. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16101824. [PMID: 31126012 PMCID: PMC6572018 DOI: 10.3390/ijerph16101824] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/17/2019] [Accepted: 05/21/2019] [Indexed: 01/12/2023]
Abstract
Our previous research using Octodon degus (degus) revealed that preweaning social isolation negatively affected object exploratory behavior. However, it remains unknown how social isolation affects animal psychology and other behaviors. The present study examined the effects of neonatal social isolation on degu emotion and mother–infant interactions before and after weaning. Because degus have a complex social repertoire, we predicted that they would be sensitive to social isolation and show similarities with humans in their social interaction. Pups in the isolation group were separated from their family seven times for 30 min a day from 8 to 15 days post-birth. Pups in the nonisolation group were reared with their family. At 2, 3, 4, 5, and 6 weeks of age, pups underwent a zero-maze test to measure anxiety and a mother–infant interaction test to assess mother–infant attachment. Isolated pups showed more activity in the zero-maze test than nonisolated pups at 3 weeks of age. We found no significant effects of social isolation on mother–infant interactions. These results suggest that while neonatal social isolation might affect emotion during weaning, it does not influence mother–infant relationships.
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Filippa M, Poisbeau P, Mairesse J, Monaci MG, Baud O, Hüppi P, Grandjean D, Kuhn P. Pain, Parental Involvement, and Oxytocin in the Neonatal Intensive Care Unit. Front Psychol 2019; 10:715. [PMID: 31001173 PMCID: PMC6454868 DOI: 10.3389/fpsyg.2019.00715] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/14/2019] [Indexed: 12/16/2022] Open
Abstract
Preterm infants (PTI) typically experience many painful and stressful procedures or events during their first weeks of life in a neonatal intensive care unit, and these can profoundly impact subsequent brain development and function. Several protective interventions during this sensitive period stimulate the oxytocin system, reduce pain and stress, and improve brain development. This review provides an overview of the environmental risk factors experienced by PTI during hospitalization, with a focus on the effects of pain, and early maternal separation. We also describe the long-term adverse effects of the simultaneous experiences of pain and maternal separation, and the potential beneficial effects of maternal vocalizations, parental contact, and several related processes, which appear to be mediated by the oxytocin system.
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Affiliation(s)
- Manuela Filippa
- Division of Development and Growth, Department of Paediatrics, Gynaecology and Obstetrics, University of Geneva, Geneva, Switzerland.,Neuroscience of Emotion and Affective Dynamics Laboratory, Department of Psychology and Educational Sciences, Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland.,Department of Social Sciences, University of Valle d'Aosta, Aosta, Italy
| | - Pierrick Poisbeau
- Centre National de la Recherche Scientifique, Institute for Cellular and Integrative Neurosciences, University of Strasbourg, Strasbourg, France
| | - Jérôme Mairesse
- INSERM U1141 Protect, Paris-Diderot University, Paris, France.,Division of Neonatology and Paediatric Intensive Care, Department of Paediatrics, Gynaecology and Obstetrics, Universtiy of Geneva, Geneva, Switzerland
| | | | - Olivier Baud
- INSERM U1141 Protect, Paris-Diderot University, Paris, France.,Division of Neonatology and Paediatric Intensive Care, Department of Paediatrics, Gynaecology and Obstetrics, Universtiy of Geneva, Geneva, Switzerland.,Service de Médecine et Réanimation Néonatale, Hôpital de Hautepierre, Centre Hospitalier Universitaire de Strasbourg, Strasbourg, France
| | - Petra Hüppi
- Division of Development and Growth, Department of Paediatrics, Gynaecology and Obstetrics, University of Geneva, Geneva, Switzerland.,Division of Neonatology and Paediatric Intensive Care, Department of Paediatrics, Gynaecology and Obstetrics, Universtiy of Geneva, Geneva, Switzerland
| | - Didier Grandjean
- Neuroscience of Emotion and Affective Dynamics Laboratory, Department of Psychology and Educational Sciences, Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland
| | - Pierre Kuhn
- Centre National de la Recherche Scientifique, Institute for Cellular and Integrative Neurosciences, University of Strasbourg, Strasbourg, France.,Service de Médecine et Réanimation Néonatale, Hôpital de Hautepierre, Centre Hospitalier Universitaire de Strasbourg, Strasbourg, France
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15
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Bock J, Breuer S, Poeggel G, Braun K. Early life stress induces attention-deficit hyperactivity disorder (ADHD)-like behavioral and brain metabolic dysfunctions: functional imaging of methylphenidate treatment in a novel rodent model. Brain Struct Funct 2016; 222:765-780. [PMID: 27306789 PMCID: PMC5334429 DOI: 10.1007/s00429-016-1244-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 05/28/2016] [Indexed: 02/02/2023]
Abstract
In a novel animal model Octodon degus we tested the hypothesis that, in addition to genetic predisposition, early life stress (ELS) contributes to the etiology of attention-deficit hyperactivity disorder-like behavioral symptoms and the associated brain functional deficits. Since previous neurochemical observations revealed that early life stress impairs dopaminergic functions, we predicted that these symptoms can be normalized by treatment with methylphenidate. In line with our hypothesis, the behavioral analysis revealed that repeated ELS induced locomotor hyperactivity and reduced attention towards an emotionally relevant acoustic stimulus. Functional imaging using (14C)-2-fluoro-deoxyglucose-autoradiography revealed that the behavioral symptoms are paralleled by metabolic hypoactivity of prefrontal, mesolimbic and subcortical brain areas. Finally, the pharmacological intervention provided further evidence that the behavioral and metabolic dysfunctions are due to impaired dopaminergic neurotransmission. Elevating dopamine in ELS animals by methylphenidate normalized locomotor hyperactivity and attention-deficit and ameliorated brain metabolic hypoactivity in a dose-dependent manner.
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Affiliation(s)
- J Bock
- Institute of Biology, Department of Zoology/Developmental Neurobiology, Otto von Guericke University, Leipziger Str. 44, 39118, Magdeburg, Germany
- Center for Behavioral Brain Science, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - S Breuer
- Institute of Biology, Department of Zoology/Developmental Neurobiology, Otto von Guericke University, Leipziger Str. 44, 39118, Magdeburg, Germany
| | - G Poeggel
- Institute for Biology, Human Biology, University of Leipzig, 04103, Leipzig, Germany
| | - K Braun
- Institute of Biology, Department of Zoology/Developmental Neurobiology, Otto von Guericke University, Leipziger Str. 44, 39118, Magdeburg, Germany.
- Center for Behavioral Brain Science, Otto von Guericke University Magdeburg, Magdeburg, Germany.
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16
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Bock J, Rether K, Gröger N, Xie L, Braun K. Perinatal programming of emotional brain circuits: an integrative view from systems to molecules. Front Neurosci 2014; 8:11. [PMID: 24550772 PMCID: PMC3913903 DOI: 10.3389/fnins.2014.00011] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 01/17/2014] [Indexed: 02/06/2023] Open
Abstract
Environmental influences such as perinatal stress have been shown to program the developing organism to adapt brain and behavioral functions to cope with daily life challenges. Evidence is now accumulating that the specific and individual effects of early life adversity on the functional development of brain and behavior emerge as a function of the type, intensity, timing and the duration of the adverse environment, and that early life stress (ELS) is a major risk factor for developing behavioral dysfunctions and mental disorders. Results from clinical as well as experimental studies in animal models support the hypothesis that ELS can induce functional “scars” in prefrontal and limbic brain areas, regions that are essential for emotional control, learning and memory functions. On the other hand, the concept of “stress inoculation” is emerging from more recent research, which revealed positive functional adaptations in response to ELS resulting in resilience against stress and other adversities later in life. Moreover, recent studies indicate that early life experiences and the resulting behavioral consequences can be transmitted to the next generation, leading to a transgenerational cycle of adverse or positive adaptations of brain function and behavior. In this review we propose a unifying view of stress vulnerability and resilience by connecting genetic predisposition and programming sensitivity to the context of experience-expectancy and transgenerational epigenetic traits. The adaptive maturation of stress responsive neural and endocrine systems requires environmental challenges to optimize their functions. Repeated environmental challenges can be viewed within the framework of the match/mismatch hypothesis, the outcome, psychopathology or resilience, depends on the respective predisposition and on the context later in life.
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Affiliation(s)
- Jörg Bock
- PG "Epigenetics and Structural Plasticity", Institute of Biology, Otto von Guericke University Magdeburg Magdeburg, Germany ; Center for Behavioral Brain Sciences Magdeburg, Germany
| | - Kathy Rether
- PG "Epigenetics and Structural Plasticity", Institute of Biology, Otto von Guericke University Magdeburg Magdeburg, Germany ; Department of Zoology/Developmental Neurobiology, Institute of Biology, Otto von Guericke University Magdeburg Magdeburg, Germany
| | - Nicole Gröger
- Department of Zoology/Developmental Neurobiology, Institute of Biology, Otto von Guericke University Magdeburg Magdeburg, Germany
| | - Lan Xie
- PG "Epigenetics and Structural Plasticity", Institute of Biology, Otto von Guericke University Magdeburg Magdeburg, Germany ; Department of Zoology/Developmental Neurobiology, Institute of Biology, Otto von Guericke University Magdeburg Magdeburg, Germany
| | - Katharina Braun
- Center for Behavioral Brain Sciences Magdeburg, Germany ; Department of Zoology/Developmental Neurobiology, Institute of Biology, Otto von Guericke University Magdeburg Magdeburg, Germany
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17
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Kunzler J, Braun K, Bock J. Early life stress and sex-specific sensitivity of the catecholaminergic systems in prefrontal and limbic regions of Octodon degus. Brain Struct Funct 2013; 220:861-8. [PMID: 24343570 DOI: 10.1007/s00429-013-0688-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 12/06/2013] [Indexed: 01/09/2023]
Abstract
Previous work in the precocious rodent Octodon degus has shown that exposure to early life stress (ELS) (induced by repeated parental separation) results in changes of excitatory, inhibitory and modulatory transmitter systems in prefrontal and limbic regions of the male brain. The aim of this study was to test the hypothesis that catecholaminergic fibers and dopamine transporters (DAT) are differentially vulnerable towards ELS-induced neuronal changes in male and female brains. The brains of adult male and female animals exposed to repeated early life stress (1 h/day separation from the family from P1 to P21) and control animals were compared and the densities of tyrosine hydroxylase (TH)-immunoreactive structures were quantified in prefrontal cortical regions. In the nucleus accumbens (NAc) and striatum, DAT-immunoreactivity as well as TH immunoreactivity was measured. Layer II of the prelimbic cortex displayed reduced TH-fiber densities in ELS males compared to control males; this effect was not seen in females. In contrast, layer V/VI of the lateral orbitofrontal cortex displayed elevated fiber densities in ELS males compared to controls; again this difference was not observed in females. The same trend was observed for layer III/IV of the ventral orbitofrontal cortex. No sex-specific effects in response to ELS were observed for DAT, whose density was elevated in the NAc of ELS males and females. These results are in line with our working hypothesis that ELS affects the development of catecholaminergic systems and we show here that ELS-induced differences of TH-immunoreactive fibers were more pronounced in male brains than in female brains.
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Affiliation(s)
- Jan Kunzler
- Department of Zoology/Developmental Neurobiology, Institute of Biology, Otto von Guericke University Magdeburg, Magdeburg, Germany
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18
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Poremba A, Bigelow J, Rossi B. Processing of communication sounds: contributions of learning, memory, and experience. Hear Res 2013; 305:31-44. [PMID: 23792078 DOI: 10.1016/j.heares.2013.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 05/09/2013] [Accepted: 06/10/2013] [Indexed: 11/17/2022]
Abstract
Abundant evidence from both field and lab studies has established that conspecific vocalizations (CVs) are of critical ecological significance for a wide variety of species, including humans, non-human primates, rodents, and other mammals and birds. Correspondingly, a number of experiments have demonstrated behavioral processing advantages for CVs, such as in discrimination and memory tasks. Further, a wide range of experiments have described brain regions in many species that appear to be specialized for processing CVs. For example, several neural regions have been described in both mammals and birds wherein greater neural responses are elicited by CVs than by comparison stimuli such as heterospecific vocalizations, nonvocal complex sounds, and artificial stimuli. These observations raise the question of whether these regions reflect domain-specific neural mechanisms dedicated to processing CVs, or alternatively, if these regions reflect domain-general neural mechanisms for representing complex sounds of learned significance. Inasmuch as CVs can be viewed as complex combinations of basic spectrotemporal features, the plausibility of the latter position is supported by a large body of literature describing modulated cortical and subcortical representation of a variety of acoustic features that have been experimentally associated with stimuli of natural behavioral significance (such as food rewards). Herein, we review a relatively small body of existing literature describing the roles of experience, learning, and memory in the emergence of species-typical neural representations of CVs and auditory system plasticity. In both songbirds and mammals, manipulations of auditory experience as well as specific learning paradigms are shown to modulate neural responses evoked by CVs, either in terms of overall firing rate or temporal firing patterns. In some cases, CV-sensitive neural regions gradually acquire representation of non-CV stimuli with which subjects have training and experience. These results parallel literature in humans describing modulation of responses in face-sensitive neural regions through learning and experience. Thus, although many questions remain, the available evidence is consistent with the notion that CVs may acquire distinct neural representation through domain-general mechanisms for representing complex auditory objects that are of learned importance to the animal. This article is part of a Special Issue entitled "Communication Sounds and the Brain: New Directions and Perspectives".
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Affiliation(s)
- Amy Poremba
- University of Iowa, Dept. of Psychology, Div. Behavioral & Cognitive Neuroscience, E11 SSH, Iowa City, IA 52242, USA; University of Iowa, Neuroscience Program, Iowa City, IA 52242, USA.
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19
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Hall FS, Perona MTG. Have studies of the developmental regulation of behavioral phenotypes revealed the mechanisms of gene-environment interactions? Physiol Behav 2012; 107:623-40. [PMID: 22643448 PMCID: PMC3447116 DOI: 10.1016/j.physbeh.2012.05.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 05/15/2012] [Accepted: 05/15/2012] [Indexed: 12/30/2022]
Abstract
This review addresses the recent convergence of our long-standing knowledge of the regulation of behavioral phenotypes by developmental experience with recent advances in our understanding of mechanisms regulating gene expression. This review supports a particular perspective on the developmental regulation of behavioral phenotypes: That the role of common developmental experiences (e.g. maternal interactions, peer interactions, exposure to a complex environment, etc.) is to fit individuals to the circumstances of their lives within bounds determined by long-standing (evolutionary) mechanisms that have shaped responses to critical and fundamental types of experience via those aspects of gene structure that regulate gene expression. The phenotype of a given species is not absolute for a given genotype but rather variable within bounds that is determined by mechanisms regulated by experience (e.g. epigenetic mechanisms). This phenotypic variation is not necessarily random, or evenly distributed along a continuum of description or measurement, but often highly disjointed, producing distinct, even opposing, phenotypes. The potentiality for these varying phenotypes is itself the product of evolution, the potential for alternative phenotypes itself conveying evolutionary advantage. Examples of such phenotypic variation, resulting from environmental or experiential influences, have a long history of study in neurobiology, and a number of these will be discussed in this review: neurodevelopmental experiences that produce phenotypic variation in visual perception, cognitive function, and emotional behavior. Although other examples will be discussed, particular emphasis will be made on the role of social behavior on neurodevelopment and phenotypic determination. It will be argued that an important purpose of some aspects of social behavior is regulation of neurobehavioral phenotypes by experience via genetic regulatory mechanisms.
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Affiliation(s)
- F Scott Hall
- Molecular Neurobiology Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, 333 Cassel Drive, Baltimore, MD 21224, United States.
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20
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Bock J, Riedel A, Braun K. Differential changes of metabolic brain activity and interregional functional coupling in prefronto-limbic pathways during different stress conditions: functional imaging in freely behaving rodent pups. Front Cell Neurosci 2012; 6:19. [PMID: 22590453 PMCID: PMC3349270 DOI: 10.3389/fncel.2012.00019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 04/14/2012] [Indexed: 11/13/2022] Open
Abstract
The trumpet-tailed rat or degu (Octodon degus) is an established model to investigate the consequences of early stress on the development of emotional brain circuits and behavior. The aim of this study was to identify brain circuits, that respond to different stress conditions and to test if acute stress alters functional coupling of brain activity among prefrontal and limbic regions. Using functional imaging (2-Fluoro-deoxyglucose method) in 8-day-old male degu pups the following stress conditions were compared: (A) pups together with parents and siblings (control), (B) separation of the litter from the parents, (C) individual separation from parents and siblings, and (D) individual separation and presentation of maternal calls. Condition (B) significantly downregulated brain activity in the prefrontal cortex, hippocampus, nucleus accumbens (NAcc), and sensory areas compared to controls. Activity decrease was even more pronounced during condition (C), where, in contrast to all other regions, activity in the PAG was increased. Interestingly, brain activity in stress-associated brain regions such as the amygdala and habenula was not affected. In condition (D) maternal vocalizations "reactivated" brain activity in the cingulate and precentral medial cortex, NAcc, and striatum and in sensory areas. In contrast, reduced activity was measured in the prelimbic and infralimbic cortex (IL) and in the hippocampus and amygdala. Correlation analysis revealed complex, region- and situation-specific changes of interregional functional coupling among prefrontal and limbic brain regions during stress exposure. We show here for the first time that early life stress results in a widespread reduction of brain activity in the infant brain and changes interregional functional coupling. Moreover, maternal vocalizations can partly buffer stress-induced decrease in brain activity in some regions and evoked very different functional coupling patterns compared to the three other conditions.
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Affiliation(s)
- Jörg Bock
- Center for Behavioral Brain Sciences MagdeburgMagdeburg, Germany
- PG Structural Plasticity, Institute of Biology, Otto-von-Guericke UniversityMagdeburg, Germany
| | - Anett Riedel
- Department of Zoology/Developmental Neurobiology, Institute of Biology, Otto-von-Guericke UniversityMagdeburg, Germany
| | - Katharina Braun
- Center for Behavioral Brain Sciences MagdeburgMagdeburg, Germany
- Department of Zoology/Developmental Neurobiology, Institute of Biology, Otto-von-Guericke UniversityMagdeburg, Germany
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Colonnello V, Iacobucci P, Fuchs T, Newberry RC, Panksepp J. Octodon degus. A useful animal model for social-affective neuroscience research: basic description of separation distress, social attachments and play. Neurosci Biobehav Rev 2011; 35:1854-63. [PMID: 21477615 DOI: 10.1016/j.neubiorev.2011.03.014] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Revised: 03/16/2011] [Accepted: 03/25/2011] [Indexed: 11/30/2022]
Abstract
A challenge for social-affective neuroscience programs is to identify simple and yet valid animal models for studying the expression of basic social emotions and their role during different developmental windows, from infancy to adulthood. For example, although laboratory rats are useful for studying juvenile social interactions, they are not ideal for studying infant attachment bonds. Here, we evaluate current understanding of the social behavior of Octodon degus, a diurnal precocial rodent, to elucidate the value of this species as a model for social-affective neuroscience research. After a synopsis of species-specific characteristics and brain susceptibility to changes of social environment, our behavioral findings on degu social proclivities are summarized. We then discuss why this pre-clinical model provides a valuable addition to the commonly available animal models for the study of human psychopathology.
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Affiliation(s)
- Valentina Colonnello
- Center for the Study of Animal Well-being, Department of Veterinary & Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, WA 99164-6520, USA.
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Colonnello V, Iacobucci P, Panksepp J. Analysis of the disruption of maternal social bonds in Octodon degus: Separation distress in restricted reunion tests. Dev Psychobiol 2011; 53:657-69. [DOI: 10.1002/dev.20539] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 01/31/2011] [Indexed: 12/24/2022]
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Jekl V, Hauptman K, Knotek Z. Diseases in pet degus: a retrospective study in 300 animals. J Small Anim Pract 2011; 52:107-12. [DOI: 10.1111/j.1748-5827.2010.01028.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Hayes LD, Burger JR, Soto-Gamboa M, Sobrero R, Ebensperger LA. Towards an integrative model of sociality in caviomorph rodents. J Mammal 2011; 92:65-77. [PMID: 22328791 PMCID: PMC3277430 DOI: 10.1644/10-mamm-s-039.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In the late 1990s and early 2000s it was recognized that behavioral ecologists needed to study the sociality of caviomorph rodents (New World hystricognaths) before generalizations about rodent sociality could be made. Researchers identified specific problems facing individuals interested in caviomorph sociality, including a lack of information on the proximate mechanisms of sociality, role of social environment in development, and geographical or intraspecific variation in social systems. Since then researchers have described the social systems of many previously understudied species, including some with broad geographical ranges. Researchers have done a good job of determining the role of social environments in development and identifying the costs and benefits of social living. However, relatively little is known about the proximate mechanisms of social behavior and fitness consequences, limiting progress toward the development of integrative (evolutionary-mechanistic) models for sociality. To develop integrative models behavioral ecologists studying caviomorph rodents must generate information on the fitness consequences of different types of social organization, brain mechanisms, and endocrine substrates of sociality. We review our current understanding and future directions for research in these conceptual areas. A greater understanding of disease ecology, particularly in species carrying Old World parasites, is needed before we can identify potential links between social phenotypes, mechanism, and fitness.
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Affiliation(s)
- Loren D. Hayes
- Department of Biology, 700 University Avenue, University of Louisiana at Monroe, Monroe, LA 72109, USA
| | - Joseph Robert Burger
- Department of Biology, 700 University Avenue, University of Louisiana at Monroe, Monroe, LA 72109, USA
- Department of Biology, MSC03 2020/1, University of New Mexico, Albuquerque, NM 87131, USA
| | - Mauricio Soto-Gamboa
- Instituto de Ecología y Evolución, Facultad de Ciencias, Universidad Austral de Chile, Isla teja S/N, Casilla 567, Chile
| | - Raúl Sobrero
- Centro de Estudios Avanzados en Ecología y Biodiversidad and Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O’Higgins 340, Santiago, Chile
| | - Luis A Ebensperger
- Centro de Estudios Avanzados en Ecología y Biodiversidad and Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O’Higgins 340, Santiago, Chile
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Bock J, Braun K. The impact of perinatal stress on the functional maturation of prefronto-cortical synaptic circuits: implications for the pathophysiology of ADHD? PROGRESS IN BRAIN RESEARCH 2011; 189:155-69. [PMID: 21489388 DOI: 10.1016/b978-0-444-53884-0.00023-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Enriched as well as impoverished or adverse perinatal environment plays an essential role in the development and refinement of neuronal pathways, which are the neural substrate of intellectual capacity and socioemotional competence. Perinatal experience and learning events continuously interact with the adaptive shaping of excitatory, inhibitory, and neuromodulatory synaptic as well as the endocrine stress systems, including the neuronal corticotropin-releasing factor (CRF) pathways. Adverse environments, such as stress and emotional deprivation can not only delay experience-dependent maturation of these pathways, but also induce permanent changes in prefronto-cortical wiring patterns. We assume that such dysfunctional connections are the neuronal basis for the development of psychosocially induced mental disorders during later life. The aim of this review is to focus on the impact of perinatal stress on the neuronal and synaptic reorganization during brain development and possible implications for the etiology and therapy of mental disorders such as ADHD.
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Affiliation(s)
- Jörg Bock
- Department of Zoology and Developmental Neurobiology, Institute of Biology, Otto von Guericke UniversityMagdeburg, Magdeburg, Germany
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Colonnello V, Iacobucci P, Anderson MP, Panksepp J. Brief periods of positive peer interactions mitigate the effects of total social isolation in young Octodon degus. Dev Psychobiol 2010; 53:280-90. [DOI: 10.1002/dev.20520] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 10/18/2010] [Indexed: 11/11/2022]
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Gunnar MR. A commentary on deprivation-specific psychological patterns: effects of institutional deprivation. Monogr Soc Res Child Dev 2010; 75:232-47. [PMID: 20500642 DOI: 10.1111/j.1540-5834.2010.00559.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This monograph will likely become a classic. It provides critical insights into identifying which threads to pull in the "web of causation" (see chapter IX) to discern the impact of adverse early life experiences, and it provides guidance regarding how to identify patterns of behavior that are likely to reflect the impact of such experiences. Not everyone will agree with all the decisions and, hence, all the conclusions made by these authors. Indeed, I have concerns about some of them as I discuss below. However, the authors provide access to their deliberative process in such a rich way that the reader can follow not only what they did but also the many considerations behind their choices, their own equivocating and reversals as more data accumulated, and the broad theoretical concerns that guided their decisions. Because "natural experiments" always confront researchers with difficult choices among never perfect options, their decision to provide a detailed discussion of their deliberative process, in addition to the richness of their data and the importance of their topic, is what makes this a likely classic in the field.
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Stress inoculation facilitates active avoidance learning of the semi-precocial rodent Octodon degus. Behav Brain Res 2010; 213:293-303. [PMID: 20580648 DOI: 10.1016/j.bbr.2010.05.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 05/11/2010] [Indexed: 01/20/2023]
Abstract
A growing body of evidence highlights the impact of the early social environment for the adequate development of brain and behavior in animals and humans. Disturbances of this environment were found to be both maladaptive and adaptive to emotional and cognitive function. Using the semi-precocial, biparental rodent Octodon degus, we aimed to examine (i) the impact of age (juvenile/adult), sex (male/female), and (ii) "motivation" to solve the task (by applying increasing foot-shock-intensities) on two-way active avoidance (TWA) learning in socially reared degus, and (iii) whether early life stress inoculation by 1h daily parental separation during the first three weeks of life has maladaptive or adaptive consequences on cognitive function as measured by TWA learning. Our results showed that (i) juvenile degus, unlike altricial rats of the same age, can successfully learn the TWA task comparable to adults, and (ii) that learning performance improves with increasing "task motivation", irrespective of age and sex. Furthermore, we revealed that (iii) stress inoculation improves avoidance learning, particularly in juvenile males, quantitatively and qualitatively depending on "task motivation". In conclusion, the present study describes for the first time associative learning in O. degus and its modulation by early life stress experience as an animal model to study the underlying mechanisms of learning and memory in the stressed and unstressed brain. Although, stress is commonly viewed as being maladaptive, our data indicate that early life stress inoculation triggers developmental cascades of adaptive functioning, which may improve cognitive and emotional processing of stressors later in life.
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Barnes maze performance of Octodon degus is gender dependent. Behav Brain Res 2010; 212:159-67. [PMID: 20385170 DOI: 10.1016/j.bbr.2010.04.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Revised: 03/30/2010] [Accepted: 04/05/2010] [Indexed: 11/22/2022]
Abstract
Gender differences in spatial navigation have been widely reported in nocturnal rodent species. Here, for the first time we report gender differences in spatial learning and memory of Octodon degus, a long-lived diurnal hystricomorph rodent. In the present study, 16 months old male and female O. degus were tested in the 18-holes Barnes circular maze. The acquisition session consisted of four daily 4 min trials, during 10 days. Seven days later, the retention test was performed. To avoid the effect of hormonal fluctuation on spatial navigation, both the acquisition and the retention tests, were performed in 21-day regular cycling females in a period that corresponds to the diestrus phase of the estrus cycle. At the beginning of the acquisition, female degus were significantly slower than males to find the escape hole, but the situation reversed afterwards. Moreover, during the course of acquisition, females made significantly less reference memory errors, working memory errors as well as omission errors, than males. In both sexes, motivation and learning ceiling effects were reached at days 5-6 of the training. During the acquisition, females used more frequently a spatial strategy, while males preferably applied either serial, random or opposite strategies. The observed cognitive differences between male and female O. degus existed only during the acquisition period but not during the retention, indicating that acquisition and consolidation are differently influenced by gender.
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Spivey JM, Shumake J, Colorado RA, Conejo-Jimenez N, Gonzalez-Pardo H, Gonzalez-Lima F. Adolescent female rats are more resistant than males to the effects of early stress on prefrontal cortex and impulsive behavior. Dev Psychobiol 2009; 51:277-88. [PMID: 19125421 DOI: 10.1002/dev.20362] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We tested the hypothesis that adolescent Sprague-Dawley females may be more resistant than males to display impulsive behavior and lower prefrontal cortex thickness after mother-infant separation (MS). Starting at postnatal day 2 (P2), the MS group was separated 6 hr/day and the early handled (EH) group 15 min/day for 10 days, and another group was standard facility reared (SFR). Subjects were examined for novel open-field activity (P28), light-dark apparatus (P29), familiar open-field (P30) and frontal cortical thickness. This protocol resulted in impulsive behavior in MS rats relative to EH and SFR, but this effect was less pronounced in females than males. MS affected the two sexes differently in terms of decreased prefrontal cortex dorsoventral thickness, with this effect being significant in males but not females. Neuroanatomical and behavioral documentation that adolescent females are more resistant than males to ADHD-like effects of maternal separation have not been previously reported.
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Affiliation(s)
- Jaclyn M Spivey
- Department of Psychology, Pharmacology and Toxicology, University of Texas at Austin, 1 University Station A8000, Austin, Texas 78712, USA
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Long CV, Ebensperger LA. Pup Growth Rates and Breeding Female Weight Changes in Two Populations of Captive Bred Degus (Octodon degus), a Precocial Caviomorph Rodent. Reprod Domest Anim 2009; 45:975-82. [DOI: 10.1111/j.1439-0531.2009.01470.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Spivey JM, Colorado RA, Conejo-Jimenez N, Gonzalez-Pardo H, Gonzalez-Lima F. Juvenile male rats display lower cortical metabolic capacity than females. Neurosci Lett 2008; 440:255-9. [PMID: 18579304 DOI: 10.1016/j.neulet.2008.05.104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 05/28/2008] [Accepted: 05/30/2008] [Indexed: 10/22/2022]
Abstract
The juvenile brain undergoes marked maturational changes accompanied by major sex hormone changes. In particular, sex differences in neural substrates could underlie male-specific dysfunction in behavioral responses related to the prefrontal cortex. Sex differences in regional metabolic capacity of the cerebral cortex were investigated in juvenile Sprague-Dawley rats. At 6 weeks of age the brains were processed for quantitative histochemistry of cytochrome oxidase, a rate-limiting enzyme in cellular respiration, which is an index of brain metabolic capacity. Quantitative image analysis revealed a main effect of sex with males displaying lower regional metabolic capacity than females in the dorsolateral and orbital prefrontal cortex and in the posterior parietal cortex. In addition, males separated for 6 h/day from their mothers as pups showed greater ambulatory behavior in the novel open field and higher metabolism in the posterior parietal cortex relative to males separated for 15 min/day. This is the first study to show sex differences in brain metabolic capacity in regions such as the prefrontal cortex that may be hypometabolic in juvenile males relative to females.
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Affiliation(s)
- Jaclyn M Spivey
- Departments of Psychology, Pharmacology and Toxicology, University of Texas at Austin, 1 University Station A8000, Austin, TX 78712, USA
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Spivey J, Barrett D, Padilla E, Gonzalez-Lima F. Mother-infant separation leads to hypoactive behavior in adolescent Holtzman rats. Behav Processes 2008; 79:59-65. [PMID: 18585869 DOI: 10.1016/j.beproc.2008.05.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Revised: 05/05/2008] [Accepted: 05/16/2008] [Indexed: 02/04/2023]
Abstract
This is the first study of the effects of mother-infant separation (MS) on adolescent behavior of Holtzman (HO) rats. Different rat strains, such as Harlan Sprague-Dawley and HO, share a common origin. However, MS may lead to hypoactive behavioral effects in HO rats because of their greater susceptibility to show depressive-like responses to stress. Sixty HO pups were divided into three groups at postnatal day 2 (P2). For 10 days, the MS group was separated 6h daily and the early handled (EH) group 15 min daily. A standard facility reared (SFR) group was not separated. Animals were tested for novel open-field activity (P28), defensive withdrawal in a light-dark (LD) apparatus (P29) and familiar open-field (P30). Behavioral measures were classified into general activity (ambulatory and short movement time), orienting (rearing time) and risk-taking (velocity and exposed zone time). MS rats displayed reductions in general activity and risk-taking, and increases in orienting time. In contrast, EH favored risk-taking behavior, which may be consistent with previous findings implicating early handling as beneficial in coping with stress. Sex differences in these behaviors were limited. This study suggests a genetic predisposition in HO rats for predominantly hypoactive/anxiety-like behaviors when exposed to an early life stressor.
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Affiliation(s)
- Jaclyn Spivey
- Department of Psychology and Institute for Neuroscience, University of Texas at Austin, Austin, TX 78712-0187, USA
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35
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Helmeke C, Ovtscharoff W, Poeggel G, Braun K. Imbalance of immunohistochemically characterized interneuron populations in the adolescent and adult rodent medial prefrontal cortex after repeated exposure to neonatal separation stress. Neuroscience 2008; 152:18-28. [DOI: 10.1016/j.neuroscience.2007.12.023] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Revised: 12/09/2007] [Accepted: 12/12/2007] [Indexed: 10/22/2022]
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Jezierski G, Zehle S, Bock J, Braun K, Gruss M. Early stress and chronic methylphenidate cross-sensitize dopaminergic responses in the adolescent medial prefrontal cortex and nucleus accumbens. J Neurochem 2007; 103:2234-44. [DOI: 10.1111/j.1471-4159.2007.04927.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Becker K, Abraham A, Kindler J, Helmeke C, Braun K. Exposure to neonatal separation stress alters exploratory behavior and corticotropin releasing factor expression in neurons in the amygdala and hippocampus. Dev Neurobiol 2007; 67:617-29. [PMID: 17443812 DOI: 10.1002/dneu.20372] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Evidence is accumulating that early emotional experience interferes with the development of the limbic system, which is involved in perception and regulation of emotional behaviors as well as in learning and memory formation. Limbic brain regions, as well as hypothalamic regions and other, nonlimbic areas contain specific neuron subpopulations, which express and release corticotropin releasing factor (CRF). Since these neurons serve to connect limbic function to endocrine, stress-related responses, we proposed that stressful experience during early postnatal brain development should interfere with the development of CRF-containing neurons, particularly in brain regions essential for emotional regulation. Applying neonatal separation stress (daily 1 h separation from the parents and litter mates) as stressor, the number of immunocytochemically identified CRF-expressing neurons/fibers was quantified in the amygdala, hippocampus, paraventricular nucleus of the hypothalamus, piriform cortex, and the somatosensory cortex of 3-week-old stressed and nonstressed Octodon degus, a semi-precocial rodent. Compared to controls neonatally stressed animals showed significantly lower levels of CRF-positive fibers (-60%) in the central amygdala, significantly less CRF-positive neurons in the dentate gyrus (-28%) and the CA1 region (-29%) and significantly lower CRF cell densities in the somatosensory cortex (-26%). On the other hand, we found significantly higher numbers of CRF-immunoreactive neurons in the basolateral amygdaloid complex (+192%) of stressed animals compared to nonstressed controls. No differences in CRF-immunoreactive cell densities were detected in the other regions. Additional behavioral analysis revealed significantly elevated exploratory behavior (+34%) in stressed animals compared to controls, which might indicate reduced anxiety in the stressed animals.
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Affiliation(s)
- Katja Becker
- Department of Zoology/Developmental Neurobiology, Institute of Biology, Otto-von-Guericke University, 39118 Magdeburg, Germany
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Zehle S, Bock J, Jezierski G, Gruss M, Braun K. Methylphenidate treatment recovers stress-induced elevated dendritic spine densities in the rodent dorsal anterior cingulate cortex. Dev Neurobiol 2007; 67:1891-900. [PMID: 17874461 DOI: 10.1002/dneu.20543] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Exposing pups of the rodent species Octodon degus to periodic separation stress during the first three postnatal weeks leads to behavioral alterations, which include reduced attention towards an emotional stimulus and motoric hyperactivity. These behavioral changes, which are reminiscent of symptoms of attention deficit hyperactivity disorder (ADHD), are paralleled by synaptic changes in the dorsal anterior cingulate cortex (ACd), a limbic cortex region, which plays a key role in the modulation of attentional and executive functions. ADHD is typically treated with methylphenidate (MP), a drug acting on the dopaminergic system. However, the effect of chronic MP-treatment on neuronal and synaptic maturation in the developing brain is unknown. Applying the Golgi-Cox stainining technique, we tested in which way chronic MP-treatment interferes with dendritic and synaptic development in the ACd and whether this treatment can restore the stress-induced changes of neuronal connectivity. We found that chronic treatment with 1 mg/kg MP recovers stress-induced changes of spine densities in the ACd. Furthermore, MP-treatment resulted in increased dendritic length and complexity in both, stressed as well as unstressed control animals. These results indicate that synaptic reorganization as well as dendritic growth in the prefrontal cortex continue into prepuberty and are modulated by MP-treatment.
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Affiliation(s)
- Stefanie Zehle
- Institute of Biology, Otto von Guericke University Magdeburg, Germany
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40
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Sullivan R, Wilson DA, Feldon J, Yee BK, Meyer U, Richter-Levin G, Avi A, Michael T, Gruss M, Bock J, Helmeke C, Braun K. The International Society for Developmental Psychobiology annual meeting symposium: Impact of early life experiences on brain and behavioral development. Dev Psychobiol 2006; 48:583-602. [PMID: 17016842 PMCID: PMC1952656 DOI: 10.1002/dev.20170] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Decades of research in the area of developmental psychobiology have shown that early life experience alters behavioral and brain development, which canalizes development to suit different environments. Recent methodological advances have begun to identify the mechanisms by which early life experiences cause these diverse adult outcomes. Here we present four different research programs that demonstrate the intricacies of early environmental influences on behavioral and brain development in both pathological and normal development. First, an animal model of schizophrenia is presented that suggests prenatal immune stimulation influences the postpubertal emergence of psychosis-related behavior in mice. Second, we describe a research program on infant rats that demonstrates how early odor learning has unique characteristics due to the unique functioning of the infant limbic system. Third, we present work on the rodent Octodon degus, which shows that early paternal and/or maternal deprivation alters development of limbic system synaptic density that corresponds to heightened emotionality. Fourth, a juvenile model of stress is presented that suggests this developmental period is important in determining adulthood emotional well being. The approach of each research program is strikingly different, yet all succeed in delineating a specific aspect of early development and its effects on infant and adult outcome that expands our understanding of the developmental impact of infant experiences on emotional and limbic system development. Together, these research programs suggest that the developing organism's developmental trajectory is influenced by environmental factors beginning in the fetus and extending through adolescence, although the specific timing and nature of the environmental influence has unique impact on adult mental health.
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Affiliation(s)
- Regina Sullivan
- Department of Zoology, University of Oklahoma, Norman, OK 73072, USA.
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Gos T, Becker K, Bock J, Malecki U, Bogerts B, Poeggel G, Braun K. Early neonatal and postweaning social emotional deprivation interferes with the maturation of serotonergic and tyrosine hydroxylase-immunoreactive afferent fiber systems in the rodent nucleus accumbens, hippocampus and amygdala. Neuroscience 2006; 140:811-21. [PMID: 16632206 DOI: 10.1016/j.neuroscience.2006.02.078] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 12/23/2005] [Accepted: 02/24/2006] [Indexed: 11/26/2022]
Abstract
The impact of early emotional experience on the development of serotonergic and dopaminergic fiber innervation of the nucleus accumbens, hippocampal formation and the amygdala was quantitatively investigated in the precocious rodent Octodon degus. Two animal groups were compared: 1) degus which were repeatedly separated from their parents during the first three postnatal weeks, after weaning they were individually reared in chronic social isolation and 2) controls which were reared undisturbed with their families. In the deprived animals 5-hydroxytryptamine-immunoreactive fiber densities were increased in the core region of the nucleus accumbens (up to 126%), in the central nucleus of the amygdala (up to 112%) and in the outer subregion of the dentate gyrus stratum moleculare (up to 149%), whereas decreased fiber densities were detected in the dentate subgranular layer (down to 86%) and in the stratum lacunosum of the hippocampal cornu ammonis region 1 (down to 86%). Tyrosine hydroxylase-immunoreactive fiber densities were increased in the core (up to 115%) and shell region (up to 113%) of the nucleus accumbens of deprived animals, whereas decreased fiber densities (down to 84%) were observed in the hilus of the dentate gyrus. In the stratum granulosum and subgranular layer the fiber densities increased up to 168% and 127% respectively. In summary, these results indicate that the postnatal establishment of the monoaminergic innervation of limbic areas is modulated in response to early emotional experience, and that this environmental morphological adaptation is highly region specific.
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Affiliation(s)
- T Gos
- Institute of Forensic Medicine, Medical University of Gdansk, ul. Debowa 23, 80-204, Gdansk, Poland
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Jezierski G, Braun K, Gruss M. Epigenetic modulation of the developing serotonergic neurotransmission in the semi-precocial rodent Octodon degus. Neurochem Int 2006; 48:350-7. [PMID: 16423427 DOI: 10.1016/j.neuint.2005.11.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Accepted: 11/15/2005] [Indexed: 11/17/2022]
Abstract
Environmental influences during early life periods, particularly those provided by the mother or parents, are generally considered to have a strong impact on the development of brain and behaviour of the offspring. In the semi-precocial South American species Octodon degus, a rodent becoming increasingly popular in different laboratory research fields, the present study aimed to examine the consequences of the disturbance of the parent-offspring interaction induced by parental separation on the serotonergic neurotransmission. Based on a quantitative neurochemical approach using brain homogenates obtained from cortical regions and the hippocampus our results revealed that (i) the tissue levels of serotonin and 5-hydroxyindoleacetic acid showed in both sexes a moderate, around two-fold increase until adulthood, indicating relatively matured cortical and hippocampal serotonergic systems at birth. In addition, we found an age-, region- and sex-specific pattern of changes in the serotonergic system induced by (ii) an acute stress challenge early in life (1-h parental separation at the postnatal day 3, 8, 14 or 21) with the most pronounced effects at earlier ages (between postnatal days 3 and 14) in the female cortex and (iii) repeated stress exposure (1h daily) during the first 3 weeks of life affecting cortical regions of both sexes. Taken together, these data indicate that early life stress (i.e. parental separation) influences the developing serotonergic system in the semi-precocial O. degus, even if the brain is relatively well matured at the early stages of postnatal development.
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Affiliation(s)
- Grzegorz Jezierski
- Otto von Guericke University Magdeburg, Institute of Biology, Department of Zoology/Developmental Neurobiology, Germany
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Colorado RA, Shumake J, Conejo NM, Gonzalez-Pardo H, Gonzalez-Lima F. Effects of maternal separation, early handling, and standard facility rearing on orienting and impulsive behavior of adolescent rats. Behav Processes 2005; 71:51-8. [PMID: 16242858 DOI: 10.1016/j.beproc.2005.09.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 09/14/2005] [Accepted: 09/24/2005] [Indexed: 11/19/2022]
Abstract
Effects of maternal separation in rats have been extensively investigated, but no studies have examined its effects in rat adolescence. We examined the effects of neonatal infant-mother separation (MS) for 6h/day and early handling (EH) for 10 days during the first 2 weeks of life by comparing MS and EH groups to standard facility reared (SFR) controls. At adolescence, the animals were evaluated in a novel and familiar open-field, the light-dark box, and the sucrose consumption test. Behavioral indices included orienting behavior (rearing frequency and duration), impulsive behavior (movement velocity and risk taking by entering the center of the open field or the light compartment of the light-dark box), hyperactivity (ambulatory distance and stereotypic movement), and reward-seeking behavior (sucrose drinking time). The prolonged MS during the first 2 weeks of life resulted in decreased orienting behavior and increased impulsive behavior in adolescence. Measures of ambulatory and stereotypic movements showed that MS rats were hyperactive in the novel environment whereas EH rats were less active overall. The impulsive/hyperactive phenotype produced by this MS protocol may provide a useful animal model to investigate the neurological basis for the similar behavioral phenotype found in attention deficit/hyperactivity disorder.
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Affiliation(s)
- Rene A Colorado
- Department of Psychology, Institute for Neuroscience, University of Texas at Austin, 1 University Station A8000, Austin, TX 78712, USA
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Separation-induced receptor changes in the hippocampus and amygdala of Octodon degus: influence of maternal vocalizations. J Neurosci 2003. [PMID: 12832558 DOI: 10.1523/jneurosci.23-12-05329.2003] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Relatively little is known about the basic mechanisms that play a role in the vulnerability of the developing brain toward adverse environmental influences. Our study in the South American rodent Octodon degus revealed that repeated brief separation from the parents and exposure to an unfamiliar environment induces in the hippocampal formation of male and female pups an upregulation of D1 and 5-HT1A receptor density in the stratum radiatum and stratum lacunosum moleculare of the CA1 region. In the CA3 region, only the 5-HT1A receptors were upregulated; no changes were observed for D1 receptors in this region. GABA(A) receptor density in the hippocampus and amygdala was downregulated (nonsignificant trend) after parental separation. The acoustic presence of the mother during parental separation suppressed the D1 and 5-HT1A receptor upregulation in some regions of the hippocampus; no such suppressing influence was observed for the GABA(A) receptors. In the basomedial amygdala, the maternal calls enhanced the separation-induced 5-HT1A receptor upregulation in the male pups, whereas in the female pups the separation-induced receptor densities were not only suppressed by the maternal call but further downregulated, compared with the control group. These results demonstrate that early adverse emotional experience alters aminergic function within the hippocampus and amygdala and that the mother's voice, a powerful emotional signal, can modulate these effects in the developing limbic system.
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Ziabreva I, Schnabel R, Poeggel G, Braun K. Mother's voice "buffers" separation-induced receptor changes in the prefrontal cortex of octodon degus. Neuroscience 2003; 119:433-41. [PMID: 12770557 DOI: 10.1016/s0306-4522(03)00123-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Although the potential vulnerability of the postnatally developing brain toward adverse environmental influences is generally recognized, relatively little is known about the basic mechanisms involved. The plasticity and adaptability of the postnatally developing brain in response to adverse emotional experiences was analyzed in the South American Octodon degus. Our study revealed that repeated brief separation from the parents and exposure to an unfamiliar environment induces an up-regulation of dopamine (D1) and 5-hydroxytrytamine (5HT1(A))-receptor density in the precentral medial, anterior cingulate, prelimbic and infralimbic cortices in female pups. No significant changes of gamma aminobutyric acid (GABA(A)) receptor density were found in deprived animals of both genders. The acoustic presence of the mother during parental separation suppressed the D1-receptor up-regulation as well as the 5-HT1(A)-receptor up-regulation, again only in the female pups. These results demonstrate that that early adverse emotional experience alters aminergic function within the prefrontal cortex in the female but not the male brain. The mother's voice, a powerful emotional signal, can protect the developing cortex from separation-induced receptor changes.
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Affiliation(s)
- I Ziabreva
- Department of Zoology/Developmental Neurobiology, Otto-von-Guericke-University, Leibniz Institute for Neurobiology, Brenneckestrasse 6, 39118 Magdeburg, Germany
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