1
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Beattie UK, Mikolajczak L, Fefferman N, Romero LM. Neophobia, but not perch hopping, is sensitive to long-term chronic stress intensity. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2023; 339:1036-1043. [PMID: 37653674 DOI: 10.1002/jez.2752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/11/2023] [Accepted: 08/16/2023] [Indexed: 09/02/2023]
Abstract
To further elucidate the role that wear-and-tear plays in the transition from acute to chronic stress, we manipulated the intensity and duration of applied chronic stress to determine if behavior would respond proportionately. We brought wild house sparrows into captivity and subjected them to high-stress, medium-stress, low-stress, or captivity-only. We varied the number of stressors per day and the duration of stress periods to vary wear-and-tear, and thus the potential to exhibit chronic stress symptoms. The behaviors we assessed were neophobia (the fear of the new; assessed via food approach latency) and perch hopping (activity). We predicted that our birds would show proportionate decreases in neophobia and activity throughout a long-term chronic stress paradigm. Our results indicate that neophobia is sensitive to the intensity of chronic stress, however, the birds became more neophobic, which was the opposite of what we expected. Conversely, perch hopping did not differ across treatment groups and is thus not sensitive to the intensity of chronic stress. Together, these data show that different behavioral measurements are impacted differently by chronic stress.
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Affiliation(s)
| | | | - Nina Fefferman
- Department of Ecology and Evolutionary Biology, Department of Mathematics, University of Tennessee, Knoxville, Tennessee, USA
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2
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Beattie UK, Fefferman N, Romero LM. Varying intensities of chronic stress induce inconsistent responses in weight and plasma metabolites in house sparrows ( Passer domesticus). PeerJ 2023; 11:e15661. [PMID: 37456877 PMCID: PMC10340100 DOI: 10.7717/peerj.15661] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 06/07/2023] [Indexed: 07/18/2023] Open
Abstract
One of the biggest unanswered questions in the field of stress physiology is whether variation in chronic stress intensity will produce proportional (a gradient or graded) physiological response. We were specifically interested in the timing of the entrance into homeostatic overload, or the start of chronic stress symptoms. To attempt to fill this knowledge gap we split 40 captive house sparrows (Passer domesticus) into four groups (high stress, medium stress, low stress, and a captivity-only control) and subjected them to six bouts of chronic stress over a 6-month period. We varied the number of stressors/day and the length of each individual bout with the goal of producing groups that would experience different magnitudes of wear-and-tear. To evaluate the impact of chronic stress, at the start and end of each stress bout we measured body weight and three plasma metabolites (glucose, ketones, and uric acid) in both a fasted and fed state. All metrics showed significant differences across treatment groups, with the high stress group most frequently showing the greatest changes. However, the changes did not produce a consistent profile that matched the different chronic stress intensities. We also took samples after a prolonged recovery period of 6 weeks after the chronic stressors ended. The only group difference that persisted after 6 weeks was weight-all differences across groups in metabolites recovered. The results indicate that common blood metabolites are sensitive to stressors and may show signs of wear-and-tear, but are not reliable indicators of the intensity of long-term chronic stress. Furthermore, regulatory mechanisms are robust enough to recover within 6 weeks post-stress.
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Affiliation(s)
- Ursula K. Beattie
- Department of Biology, Tufts University, Medford, Massachusetts, United States
| | - Nina Fefferman
- Departments of Ecology and Evolution, University of Tennessee—Knoxville, Knoxville, Tennessee, United States
| | - L. Michael Romero
- Department of Biology, Tufts University, Medford, Massachusetts, United States
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3
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Kimball MG, Lattin CR. Exploration of A Novel Environment is Not Correlated With Object Neophobia in Wild-caught House Sparrows (Passer domesticus). Behav Processes 2023:104913. [PMID: 37406866 DOI: 10.1016/j.beproc.2023.104913] [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: 02/08/2023] [Revised: 05/01/2023] [Accepted: 07/01/2023] [Indexed: 07/07/2023]
Abstract
Novel object, food, and environment trials have been widely used to understand how individual variation in neophobia (an aversion to novelty) relates to variation in endocrine, physiological, and ecological traits. However, what is often missing from these studies is an evaluation of whether an animal's response to one type of neophobia test is reflective of its response to other neophobia tests. In this study we investigated whether spatial neophobia was significantly correlated with responses to a novel object paradigm. In spatial neophobia trials, wild-caught house sparrows (n = 23) were allowed access to a novel environment (an adjacent cage with familiar objects placed in new locations). Time to first enter and total time spent in the novel environment were assessed. In novel object trials, birds were exposed to a new novel object in, on, or near their food dish and time to approach and feed from the dish was measured. Results indicate that neither time spent in a novel environment nor time to first enter a novel environment were correlated with an individual's average response to novel object trials. Therefore, these two tests may be assessing two discrete behaviors that involve separate decision-making processes and functional circuits in the brain.
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Affiliation(s)
- Melanie G Kimball
- Department of Biological Sciences, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803, United States.
| | - Christine R Lattin
- Department of Biological Sciences, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803, United States
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4
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Drinkwater E, Allen WL, Endler JA, Hanlon RT, Holmes G, Homziak NT, Kang C, Leavell BC, Lehtonen J, Loeffler‐Henry K, Ratcliffe JM, Rowe C, Ruxton GD, Sherratt TN, Skelhorn J, Skojec C, Smart HR, White TE, Yack JE, Young CM, Umbers KDL. A synthesis of deimatic behaviour. Biol Rev Camb Philos Soc 2022; 97:2237-2267. [DOI: 10.1111/brv.12891] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 07/17/2022] [Accepted: 07/19/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Eleanor Drinkwater
- Department of Animal Science Writtle University College Writtle Chelmsford CM1 3RR UK
| | - William L. Allen
- Department of Biosciences Swansea University Sketty Swansea SA2 8PP UK
| | - John A. Endler
- Centre for Integrative Ecology, School of Life & Environmental Sciences Deakin University Waurn Ponds VIC 3216 Australia
| | | | - Grace Holmes
- Biosciences Institute, Faculty of Medical Sciences Newcastle University Newcastle upon Tyne NE2 4HH UK
| | - Nicholas T. Homziak
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History University of Florida Gainesville FL 32611 USA
- Entomology and Nematology Department University of Florida Gainesville FL 32611 USA
| | - Changku Kang
- Department of Biosciences Mokpo National University Muan Jeollanamdo 58554 South Korea
- Department of Agricultural Biotechnology Seoul National University Seoul 08826 South Korea
- Department of Agriculture and Life Sciences Seoul National University Seoul 08826 South Korea
| | - Brian C. Leavell
- Department of Biological Sciences Purdue University West Lafayette IN 47907 USA
| | - Jussi Lehtonen
- Faculty of Science, School of Life and Environmental Sciences The University of Sydney Sydney NSW 2006 Australia
- Department of Biological and Environmental Science University of Jyväskylä Jyväskylä 40014 Finland
| | | | - John M. Ratcliffe
- Department of Biology University of Toronto Mississauga Mississauga ON L5L 1C6 Canada
| | - Candy Rowe
- Biosciences Institute, Faculty of Medical Sciences Newcastle University Newcastle upon Tyne NE2 4HH UK
| | - Graeme D. Ruxton
- School of Biology University of St Andrews St Andrews Fife KY16 9TH UK
| | - Tom N. Sherratt
- Department of Biology Carleton University Ottawa ON K1S 5B6 Canada
| | - John Skelhorn
- Biosciences Institute, Faculty of Medical Sciences Newcastle University Newcastle upon Tyne NE2 4HH UK
| | - Chelsea Skojec
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History University of Florida Gainesville FL 32611 USA
- Entomology and Nematology Department University of Florida Gainesville FL 32611 USA
| | - Hannah R. Smart
- Hawkesbury Institute for the Environment Western Sydney University Penrith NSW 2751 Australia
| | - Thomas E. White
- Faculty of Science, School of Life and Environmental Sciences The University of Sydney Sydney NSW 2006 Australia
| | - Jayne E. Yack
- Department of Biology Carleton University Ottawa ON K1S 5B6 Canada
| | | | - Kate D. L. Umbers
- Hawkesbury Institute for the Environment Western Sydney University Penrith NSW 2751 Australia
- School of Science Western Sydney University Penrith NSW 2751 Australia
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5
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Carli G, Farabollini F. Autonomic correlates of defense responses, including tonic immobility (TI). PROGRESS IN BRAIN RESEARCH 2022; 271:191-228. [DOI: 10.1016/bs.pbr.2022.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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6
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Fischer CP, Romero LM. The effects of daily mitotane or diazepam treatment on the formation of chronic stress symptoms in newly captured wild house sparrows. CONSERVATION PHYSIOLOGY 2020; 8:coaa118. [PMID: 34970435 PMCID: PMC7771575 DOI: 10.1093/conphys/coaa118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 10/20/2020] [Accepted: 11/29/2020] [Indexed: 06/14/2023]
Abstract
Wild animals brought into captivity frequently experience chronic stress and typically need a period of time to adjust to the conditions of captivity (restraint, artificial lighting, altered diet, human presence, etc.), to which they may never fully acclimate. Changes in mass, the hypothalamic-pituitary-adrenal axis and heart rate parameters have been observed over the first week in newly captive house sparrows (Passer domesticus). In this study, we tested the effects of two drugs, diazepam and mitotane, in preventing the chronic stress symptoms caused by captivity, compared with oil-injected control animals. Diazepam is an anxiolytic that is widely prescribed in humans and other animals and has been shown in some cases to reduce physiological stress. Mitotane is an agent that causes chemical adrenalectomy, reducing the body's capacity to produce glucocorticoid hormones. Our mitotane treatment did not cause the expected change in corticosterone concentrations. Baseline corticosterone was higher after a week in captivity regardless of the treatment group, while stress-induced corticosterone did not significantly increase above baseline after a week in captivity in any treatment group. However, mitotane treatment did have some physiological effects, as it reduced the resting heart rate and the duration of the heart rate response to a sudden noise. It also prevented the increase in nighttime activity that we observed in control animals. There was no effect of diazepam on corticosterone, resting heart rate, activity or heart rate response to a sudden noise, and no effect of either treatment on the sympathetic vs parasympathetic control of the resting heart rate. Together, these data suggest that mitotane, but not diazepam, can have a modest impact on helping house sparrows adapt to captive conditions. Easing the transition to captivity will likely make conservation efforts, such as initiating captive breeding programs, more successful.
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7
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de Bruijn R, Romero LM. Chronic stress reverses enhanced neophobia following an acute stressor in European starlings. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 335:265-274. [PMID: 33231919 DOI: 10.1002/jez.2431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 11/08/2022]
Abstract
Neophobia is an animal's avoidance of novelty. Animals tend to respond to novel objects by increasing their latency to approach the objects, and they eventually habituate after repeated exposure by attenuating this increased approach latency. Interestingly, the physiological stress response does not appear to have a causal link to neophobia, although acute stress can prevent animals from habituating to novel objects, possibly through a permissive effect. Chronic stress can induce an anxiety-like state in animals, while often disrupting the ability to respond to acute stress. We thus hypothesized that chronic stress may increase neophobia and tested this by inducing chronic stress in wild-caught European starlings (Sturnus vulgaris). Four distinct anthropogenic stressors were administered daily for 30 min each in a randomized order for 21 days. We then evaluated whether exposure to chronic stress altered the latency to approach a novel object placed on or near a food dish presented after overnight fasting. Chronically stressed birds and nonstressed controls exhibited similar initial neophobic responses to novel objects and showed similar habituation in response to repeated exposure. However, when birds were exposed to 15 min of restraint before repeated exposure to the same object, habituation was eliminated in control birds (i.e., they continued to respond with neophobia), whereas chronically stressed birds continued to show habituation as measured by attenuated approach latencies. These results demonstrate that an acute stress response (restraint) has a different impact on neophobia depending upon whether the bird is or is not concurrently exposed to chronic stress.
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Affiliation(s)
- Robert de Bruijn
- Department of Biology, Tufts University, Medford, Massachusetts, USA
| | - L Michael Romero
- Department of Biology, Tufts University, Medford, Massachusetts, USA
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8
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Koizumi R, Kiyokawa Y, Tanaka KD, Kimura G, Tanikawa T, Takeuchi Y. Existence of wild brown rats (Rattus norvegicus) that are indifferent to novel objects. J Vet Med Sci 2020; 83:78-83. [PMID: 33239479 PMCID: PMC7870414 DOI: 10.1292/jvms.20-0568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exposure to novel objects typically evokes avoidance behavior in wild animals, which is called neophobia. We previously found that wild brown rats (Rattus norvegicus) that were trapped in a park in downtown Tokyo, Japan, exhibited neophobia. We also found that this behavior was accompanied by the activation of the basolateral complex of the amygdala (BLA). Previous studies have suggested that genetic factors are the primary determinants of neophobia. Since rats in cities form populations with distinct genetic characteristics, it is reasonable to assume that wild rats caught at different locations in urban centers will exhibit different levels of neophobia. Here we assessed the intensity of neophobia in wild rats trapped at a wholesale market in Tokyo. Although we performed exactly the same experiment in which neophobia was observed in wild rats trapped at the park, the presence of novel objects did not affect the behaviors of wild rats trapped at the market. Conversely, laboratory rats showed approach and exploratory behaviors as seen in the previous study, suggesting that the experiment was performed appropriately. Compared to the laboratory rats, the lack of behavioral changes in the wild rats was accompanied by fewer Fos immunoreactive cells in the BLA. In addition, the numbers of Fos immunoreactive cells in the bed nucleus of the stria terminalis and ventromedial hypothalamus were similar between the two types of rats. The results demonstrated the existence of wild rats that were indifferent to novel objects.
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Affiliation(s)
- Ryoko Koizumi
- Laboratory of Veterinary Ethology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.,Present address: Wildlife Damage Management Group, Central Region Agricultural Research Center, National Agricultural Food Research Organization, 2-1-18 Kannondaira, Tsukuba, Ibaraki 305-8666, Japan
| | - Yasushi Kiyokawa
- Laboratory of Veterinary Ethology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kazuyuki D Tanaka
- Technical Research Laboratory, Ikari Shodoku Corporation, 1-12-3 Akanehama, Narashino-shi, Chiba 275-0024, Japan
| | - Goro Kimura
- Technical Research Laboratory, Ikari Shodoku Corporation, 1-12-3 Akanehama, Narashino-shi, Chiba 275-0024, Japan
| | - Tsutomu Tanikawa
- Technical Research Laboratory, Ikari Shodoku Corporation, 1-12-3 Akanehama, Narashino-shi, Chiba 275-0024, Japan
| | - Yukari Takeuchi
- Laboratory of Veterinary Ethology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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9
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Gaidica M, Dantzer B. Quantifying the Autonomic Response to Stressors-One Way to Expand the Definition of "Stress" in Animals. Integr Comp Biol 2020; 60:113-125. [PMID: 32186720 DOI: 10.1093/icb/icaa009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Quantifying how whole organisms respond to challenges in the external and internal environment ("stressors") is difficult. To date, physiological ecologists have mostly used measures of glucocorticoids (GCs) to assess the impact of stressors on animals. This is of course too simplistic as Hans Seyle himself characterized the response of organisms to "noxious stimuli" using multiple physiological responses. Possible solutions include increasing the number of biomarkers to more accurately characterize the "stress state" of animal or just measuring different biomarkers to more accurately characterize the degree of acute or chronic stressors an animal is experiencing. We focus on the latter and discuss how heart rate (HR) and heart rate variability (HRV) may be better predictors of the degree of activation of the sympathetic-adrenal-medullary system and complement or even replace measures of GCs as indicators of animal health, welfare, fitness, or their level of exposure to stressors. The miniaturization of biological sensor technology ("bio-sensors" or "bio-loggers") presents an opportunity to reassess measures of stress state and develop new approaches. We describe some modern approaches to gathering these HR and HRV data in free-living animals with the aim that heart dynamics will be more integrated with measures of GCs as bio-markers of stress state and predictors of fitness in free-living animals.
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Affiliation(s)
- Matt Gaidica
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Ben Dantzer
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA.,Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
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10
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Gormally BMG, Estrada R, McVey M, Romero LM. Beyond corticosterone: The acute stress response increases DNA damage in house sparrows. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 333:595-606. [PMID: 32798291 DOI: 10.1002/jez.2405] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 08/02/2020] [Indexed: 12/22/2022]
Abstract
Although corticosterone (Cort) has been the predominant metric used to assess acute stress in birds, it does not always accurately reflect how an animal copes with a stressor. Downstream measurements may be more reliable. In the current study, we tested the hypothesis that acute increases in DNA damage could be used to assess stressor exposure. Studies have shown DNA damage increases in response to stress-related hormones in vitro; however, this has not yet been thoroughly applied in wild animals. We exposed house sparrows (Passer domesticus) to a 30- or 120-min restraint stressor and took blood samples at 0, 30, 60, and 120 min to measure Cort, DNA damage, and uric acid. Both treatments increased DNA damage and Cort, and decreased uric acid. It thus appears that DNA damage can reflect acute stressor exposure. To improve the usability of DNA damage as a metric for stress, we also tested the impacts of sample storage on DNA damage. Leaving red blood cells on ice for up to 24 hr, only slightly influenced DNA damage. Freezing blood samples for 1-4 weeks substantially increased DNA damage. These findings emphasize the importance of reducing variation between samples by assaying them together whenever possible. Overall, these results indicate that assessing DNA damage is a valid method of assessing acute stressor exposure that is suitable for both laboratory- and field-based studies; however, additional research is needed on the molecular dynamics of nucleated red blood cells, including whether and how their DNA is repaired.
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Affiliation(s)
| | - Rodolfo Estrada
- Department of Biology, Tufts University, Medford, Massachusetts
| | - Mitch McVey
- Department of Biology, Tufts University, Medford, Massachusetts
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11
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Fischer CP, Gormally BMG, Romero LM. Captive house sparrows (Passer domesticus) show little evidence of seasonality of neophobia responses. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 333:478-482. [PMID: 32351043 DOI: 10.1002/jez.2365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 04/03/2020] [Accepted: 04/10/2020] [Indexed: 01/13/2023]
Abstract
Neophobia is a behavior characterized by a reluctance to approach novel objects. We measured neophobia in captive wild house sparrows (Passer domesticus) by comparing the time it took for hungry birds to approach their normal food dish compared to one that had been modified with a novel object. We tested the behavior of animals captured at different times of year to test for seasonal variation in neophobia. One group of birds tested in July approached their food dishes much more quickly than all other birds (a matter of seconds rather than minutes whether or not there was a novel object), a response that was not repeated in a subsequent July. When this possible outlier group was removed from the analysis, approach times to novel objects were not affected by season. However, animals captured and tested in October had a stronger motivation to feed (i.e., they approached unmodified food dishes faster) than birds captured at other times of the year. If we define "neophobia" as an increase in latency to approach a novel versus an unmodified food dish, then there is little evidence for underlying seasonal variation in risk assessment, although a general motivation to feed does show a seasonal pattern.
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Affiliation(s)
- Clare P Fischer
- Department of Biology, Tufts University, Medford, Massachusetts
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12
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Bruijn R, Romero LM. Prior restraint stress inhibits habituation to novel objects in the European starlings (
Sturnus vulgaris
). JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2019; 333:88-95. [DOI: 10.1002/jez.2327] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 10/01/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Robert Bruijn
- Department of Biology Tufts University Medford Massachusetts
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13
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Koizumi R, Kiyokawa Y, Tanaka KD, Tanikawa T, Takeuchi Y. Novel objects elicit greater activation in the basolateral complex of the amygdala of wild rats compared with laboratory rats. J Vet Med Sci 2019; 81:1121-1128. [PMID: 31270283 PMCID: PMC6715923 DOI: 10.1292/jvms.19-0040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Wild animals tend to avoid novel objects that do not elicit clear avoidance behaviors in
domesticated animals. We previously found that the basolateral complex of the amygdala
(BLA) and dorsal bed nucleus of the stria terminalis (dBNST) were larger in trapped wild
rats compared with laboratory rats. Based on these findings, we hypothesized that the BLA
and/or dBNST would be differentially activated when wild and laboratory rats showed
different avoidance behaviors towards novel objects. In this study, we placed novel
objects at one end of the home cage. We measured the time spent in that half of the cage
and expressed the data as a percentage of the time spent in that region with no object
placement. We found that this percentage was lower in the wild rats compared with the
laboratory rats. These behavioral differences were accompanied by increased Fos expression
in the BLA, but not in the dBNST, of the wild rats. These results suggest that wild rats
show greater BLA activation compared with laboratory rats in response to novel objects. We
also found increased Fos expression in the paraventricular nucleus of the hypothalamus,
ventral BNST, and ventromedial hypothalamus, but not in the central amygdala of wild rats.
Taken together, our data represent new information regarding differences in behavioral and
neural responses towards novel objects in wild vs. laboratory rats.
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Affiliation(s)
- Ryoko Koizumi
- Laboratory of Veterinary Ethology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yasushi Kiyokawa
- Laboratory of Veterinary Ethology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kazuyuki D Tanaka
- Technical Research Laboratory, Ikari Shodoku Corporation, 1-12-3 Akanehama, Narashino-shi, Chiba 275-0024, Japan
| | - Tsutomu Tanikawa
- Technical Research Laboratory, Ikari Shodoku Corporation, 1-12-3 Akanehama, Narashino-shi, Chiba 275-0024, Japan
| | - Yukari Takeuchi
- Laboratory of Veterinary Ethology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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14
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Gormally BMG, Ramos S, Yin H, Romero LM. Recovery periods during repeated stress impact corticosterone and behavioral responses differently in house sparrows. Horm Behav 2019; 112:81-88. [PMID: 30986400 DOI: 10.1016/j.yhbeh.2019.04.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/08/2019] [Accepted: 04/11/2019] [Indexed: 01/10/2023]
Abstract
A number of studies have shown that chronic stress can negatively impact both physiology and behavior in a variety of organisms. What has yet to be extensively explored is whether these changes permanently alter an animal's functioning, or if they can be reversed. In this study, we used wild-caught house sparrows (Passer domesticus) to assess how recovery periods influence the physiological and behavioral impacts of an initial four days and subsequent four days of repeated stressors. Birds were randomly assigned to a recovery group and either experienced 0, 24, or 72 h of recovery between the two sets of stressors (cage rolling and cage tapping). We measured the regulation of the hypothalamic pituitary adrenal (HPA) axis by quantifying baseline and stress-induced corticosterone as well as negative feedback strength. We also assessed behavior using neophobia trials to measure how birds altered their approach towards novel objects and their overall activity. Both behavior and corticosterone responses were assessed before the experiment, after the recovery time, and following the final 4 days of stressors. We found that birds that experienced 24 h of recovery had reduced stress-induced corticosterone, but enhanced negative feedback relative to the pre-experiment sample. Additionally, 4 days of stressors was enough to significantly reduce approach latency towards novel objects; however, pre-experiment levels returned with longer periods of recovery. Finally, recovery time did not significantly influence responses to the second 4 days of stressors. Our results indicate that brief recovery periods partially ameliorate the hormonal and behavioral effects of repeated stress.
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Affiliation(s)
| | - Sarah Ramos
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Hannah Yin
- Department of Biology, Tufts University, Medford, MA 02155, USA
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15
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Scopa C, Palagi E, Sighieri C, Baragli P. Physiological outcomes of calming behaviors support the resilience hypothesis in horses. Sci Rep 2018; 8:17501. [PMID: 30504840 PMCID: PMC6269543 DOI: 10.1038/s41598-018-35561-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 11/07/2018] [Indexed: 01/04/2023] Open
Abstract
To manage a stressful stimulus animals react both behaviorally and physiologically to restore the homeostasis. In stable horses, a stressful stimulus can be represented by social separation, riding discomfort or the presence of novel objects in their environment. Although Heart Rate Variability is a common indicator of stress levels in horses, the behavioral mechanisms concurrently occurring under stressful conditions are still unknown. The sudden inflation of a balloon was administered to 33 horses. Video-recording of self-directed behaviors (snore, vacuum chewing, snort, head/body shaking) and monitoring of heart activity (HR and SDRR) were conducted for five minutes before (Pre-test) and after the stimulus administration (Stress-test). During the Stress-test, only snore and vacuum chewing increased and a significant increase was also recorded in both HR and SDRR. Moreover, the snore variation between the two conditions showed a significant correlation with the variation of both HR and SDRR. With the snore acting as stress-releasing behavior to restore basal condition, the homeostasis recovered via the enactment of such behavior could be physiologically expressed by an increasing vagal activity. Hence, the capacity to maintain homeostasis (resilience) could correspond to a prevalence of parasympathetic control on heart activity, intervening when certain behaviors are performed.
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Affiliation(s)
- Chiara Scopa
- Italian National Reference Centre for Animal Assisted Interventions, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro (Padua), Italy
| | - Elisabetta Palagi
- Unit of Ethology, Department of Biology, University of Pisa, Pisa, Italy
| | - Claudio Sighieri
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy
| | - Paolo Baragli
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy.
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Gormally BMG, Romero LM. House sparrows (Passer domesticus) adjusted hypothalamic-pituitary-adrenal axis negative feedback and perch hopping activities in response to a single repeated stimulus. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 329:597-605. [PMID: 30238686 DOI: 10.1002/jez.2229] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 08/18/2018] [Accepted: 08/23/2018] [Indexed: 01/08/2023]
Abstract
Chronic stress has been extensively studied in both laboratory and field settings; however, a conclusive and consistent phenotype has not been reached. Several studies have reported attenuation of the hypothalamic-pituitary-adrenal axis during experiments intended to cause chronic stress. We sought to determine whether this attenuation could be indicative of habituation. Importantly, we were not investigating habituation to a specific stimulus-as many stress physiology studies do-but rather we assessed how the underlying physiology and behavior changed in response to repeated stressor presentation. We exposed house sparrows (Passer domesticus) to a single stimulus twice per day at random times for 8 consecutive days. We predicted that this period of time would be long enough for the birds to determine that these acute stressors were not, in fact, dangerous and they would, therefore, acclimate. A second control group remained undisturbed for the same period of time. We measured baseline, stress-induced, negative feedback strength, and maximum production of corticosterone as well as neophobic behavior before, during, and after this 8-day experiment. When birds experienced a stimulus for 4 days, their negative feedback strength was significantly diminished, but recovered after the second 4 days. Additionally, perch hopping decreased and recovered in this same time frame. These data suggest that distinct physiological and behavioral responses arise when house sparrows are exposed to the same stressor for several consecutive days as opposed to many stressors layered on top of one another. Furthermore, they indicate that habituation-as with chronic stress-can appear differently depending on the metric being examined.
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17
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Brosschot JF, Verkuil B, Thayer JF. Generalized Unsafety Theory of Stress: Unsafe Environments and Conditions, and the Default Stress Response. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:E464. [PMID: 29518937 PMCID: PMC5877009 DOI: 10.3390/ijerph15030464] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 02/13/2018] [Accepted: 02/27/2018] [Indexed: 12/14/2022]
Abstract
Prolonged physiological stress responses form an important risk factor for disease. According to neurobiological and evolution-theoretical insights the stress response is a default response that is always "on" but inhibited by the prefrontal cortex when safety is perceived. Based on these insights the Generalized Unsafety Theory of Stress (GUTS) states that prolonged stress responses are due to generalized and largely unconsciously perceived unsafety rather than stressors. This novel perspective necessitates a reconstruction of current stress theory, which we address in this paper. We discuss a variety of very common situations without stressors but with prolonged stress responses, that are not, or not likely to be caused by stressors, including loneliness, low social status, adult life after prenatal or early life adversity, lack of a natural environment, and less fit bodily states such as obesity or fatigue. We argue that in these situations the default stress response may be chronically disinhibited due to unconsciously perceived generalized unsafety. Also, in chronic stress situations such as work stress, the prolonged stress response may be mainly caused by perceived unsafety in stressor-free contexts. Thus, GUTS identifies and explains far more stress-related physiological activity that is responsible for disease and mortality than current stress theories.
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Affiliation(s)
- Jos F Brosschot
- Institute of Psychology, Unit Health, Medical and Neuropsychology, Leiden University, 2300 RB Leiden, The Netherlands.
| | - Bart Verkuil
- Institute of Psychology, Unit Clinical Psychology, Leiden University, 2300 RB Leiden, The Netherlands.
| | - Julian F Thayer
- Department of Psychology, The Ohio State University, Columbus, OH 43210, USA.
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18
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Novelty induces behavioural and glucocorticoid responses in a songbird artificially selected for divergent personalities. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.06.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Abstract
Stress, whether daily stress, work stress or traumatic stress, is unhealthy. This lecture covers three recent theoretical approaches in explaining the mechanisms underlying the influence of psychological stress on somatic health. It is argued that stress research should focus less on stressors themselves and put more emphasis on prolonged stress responses. Three mechanisms are identified that cause this unhealthy prolonged stress response: first, the partly-proven mechanism of perseverative cognition; second, the mechanism of unconscious stress, which is currently being explored; and third, the notion of the stress response being a default response that is inhibited only when safety is perceived. All three mechanisms are deeply rooted in millions of years of our evolution. Although the dangers of the past have virtually disappeared, many of us remain ever at the ready for events that never happen.
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Affiliation(s)
- Jos F Brosschot
- Institute of Psychology, Health, Medical and Neuropsychology Unit, Leiden University, RB Leiden, The Netherlands
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