22 research outputs found
sj-docx-3-jbr-10.1177_07487304231154715 – Supplemental material for Temporal Dissociation Between Activity and Body Temperature Rhythms of a Subterranean Rodent (Ctenomys famosus) in Field Enclosures
No full textSupplemental material, sj-docx-3-jbr-10.1177_07487304231154715 for Temporal Dissociation Between Activity and Body Temperature Rhythms of a Subterranean Rodent (Ctenomys famosus) in Field Enclosures by Milene G. Jannetti, Patricia Tachinardi, Veronica S. Valentinuzzi and Gisele A. Oda in Journal of Biological Rhythms</p
sj-docx-1-jbr-10.1177_07487304231154715 – Supplemental material for Temporal Dissociation Between Activity and Body Temperature Rhythms of a Subterranean Rodent (Ctenomys famosus) in Field Enclosures
No full textSupplemental material, sj-docx-1-jbr-10.1177_07487304231154715 for Temporal Dissociation Between Activity and Body Temperature Rhythms of a Subterranean Rodent (Ctenomys famosus) in Field Enclosures by Milene G. Jannetti, Patricia Tachinardi, Veronica S. Valentinuzzi and Gisele A. Oda in Journal of Biological Rhythms</p
sj-docx-2-jbr-10.1177_07487304231154715 – Supplemental material for Temporal Dissociation Between Activity and Body Temperature Rhythms of a Subterranean Rodent (Ctenomys famosus) in Field Enclosures
No full textSupplemental material, sj-docx-2-jbr-10.1177_07487304231154715 for Temporal Dissociation Between Activity and Body Temperature Rhythms of a Subterranean Rodent (Ctenomys famosus) in Field Enclosures by Milene G. Jannetti, Patricia Tachinardi, Veronica S. Valentinuzzi and Gisele A. Oda in Journal of Biological Rhythms</p
Synchronization of the wheel-running activity rhythm of a tuco-tuco by light dark cycles LD 1∶23 (A) and LD 12∶12 (B).
No full text<p>The data is depicted in actograms, with times of running-wheel activity (black and dark-gray marks) represented along the days. Dark-gray marks represent free-running rhythms in the first 15 days in DD. White rectangles drawn in the graphics during the LD cycles represent the hours of lights-on. Both light-dark cycles LD 1∶23 and LD 12∶12 synchronize the rhythms of tuco-tucos to a 24 h-period. Figure B was modified from Valentinuzzi et al. (2009) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068243#pone.0068243-Valentinuzzi1" target="_blank">[1]</a>.</p
Variação circadiana na habituação da resposta exploratoria a estimulos sonoros em pombos (Columba livia), submetidos a condições de claro-escuro e de claro constante
No full textOrientador : Elenice A. de Moraes FerrariDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: Este trabalho analisou a habituação a sons no contexto da organização temporal do comportamento. O processo de habituação da resposta exploratória ao som foi analisado em três experimentos. O objetivo principal desses experimentos foi a análise dessa resposta em função do horário das sessões de habituação, i.e., matutinas ou vespertinas Os experimentos diferiram quanto aos ciclos de iluminação aos quais pombos adultos foram expostos: ciclo claro-escuro de 12:12h, no Experimento 1; claro continuo, no Experimento 2; e dois dias de claro continuo, interposto a um ciclo claro-escuro de 12:12h, no Experimento 3. Os três experimentos foram igualados quanto aos horários de teste. Os testes matutinos foram realizados às 7:30h, uma hora após o acender da luz, e às 19:30h. uma hora após o desligar da luz. Os pombos foram submetidos a apresentações de um som de 1000-Hz, 83-dB, 1s (estimulo A), a cada 30 s, até habituação das respostas exploratórias ou até um máximo de 100 estimulos, quando o critério de aprendizagem não era observado O critério de aprendizagem estabelecia a ocorrência de 10 estimulos sem o registro de respostas exploratórias. Uma segunda sessão de habituação, com a apresentação de um som de 500-Hz, 85-dB, 1s (estimulo B>, foi realizada 24h depois. O reteste, com a mesma sequência de procedimentos e inversão do horário de teste. foi realizado 18 dias ap6s a segunda sessão. Os resultados do Experimento 1 mostraram que nos testes noturnos, em comparação com os matutinos. houve um maior número de estimulações até habituação (p(O.05), tanto para o estímulo A quanto para o estimulo B. No Experimento 2 foram observadas diferenças na velocidade da habituação nos testes matutinos e noturnos, apenas nas sessees com o estimulo A (p(0,05). Os pombos expostos a dois dias de iluminação continua antes dos testes do Experimento 3 também mostraram uma di~erença noite-dia embora não significante. O conjunto de dados desses exxperimentos sugerem uma organização temporal dos processos de habituação e colocam questões relativas ao significado biológico da estimulação sonora em condições de claro e de escuro. As diferenças observadas entre os três experimentos também sugerem uma função para a melatonina na regulação desses processos. Os pombos mantidos sob iluminação constante e aqueles que ~oram expostos a dois dias de luz continua antes do teste. provavelmente caracterizados por baixos niveis de melatonina plasmática. mostraram menor velocidade de habituação em comparação com os pombos mantidos em ciclo claroescuro. Os baixos níveis de melatonina poderiam atuar no sentido de uma facilitação da habituação. Também foi argumentado um possivel efeito de estresse devido à exposição a dois dias de luz continua. Nesta condição provavelmente não haveria tempo suficiente para adaptações à nova situação de iluminação. A caracterização precisa dessas diferenças noite-dia na habituação ao som como expressão de um ritmo circadiano necessita ainda de outros estudosAbstract: The present work investigated habituation learning to acoustic stimulation in the context of temporal organization of behavior. The process of habituation of the exploratory responses to sound was analvsed in three experiments. The main purpose of these experiments was the analysis of these responses as function of the time of habituation sessions, i.e., mornins or nisht tests. The experiments differed in relation to the light cycles to which adult pigeons were exposed : 12:12h light-dark cycle in Experiment 1; continuous ilumination in Experiment 2 and twodays of continuous ilumination interposedto a 12:12 light-dark cycle, in Experiment3. Time for testins was matched for the three experimentswith morning tests at 7:30 a.m., one hour after light onset. and night tests at 7:30 p.m., one hour after turn out of light. Piseons were exposed to 1000-Hz.83-dB. ls sound (stimulus A) at 30 seconds intervals until habituation of the exploratory and startle response or until a maximum of 100 stimulus when the learning criterion was not observed. The learnins criterionwas 10 trials without the occurrence of these responses. Twenty-fourhours after habituation to stimulus A the birds were tested with a SOO-Hz, 8S-dB, 1s sound (stimulus B). Retesting. with the same sequence of proceduresbut reversal of the time of test was carried out 18 days after stimulus B habituation. Results from Experiment 1 showed an increased number of habituation trials in nocturnal (p(0,05) as compared to the morning tests for both stimulus A and B. The number of trials until habituation in the Experiment 2 showed differences between morning-night test onlv for stimulus A session. Pigeons exposed to two-davs Df continuous ilumination in Experiment 3 also showed a morning-night difference. although it was not significant. Taken together the data from these experiments suggest one temporal organization of the habituation learning processes and raises issues concerning the biological meaning of sound stimulation in light and dark environmental conditions. The differences observed between the three experiments also sugsest a role for the melatonin hormone in these processes. Pigeons maintained under continuous lisht or exposed to two-days of continuous il1umination prior to tests. which were probably characterized by decreased levels of melatonin, showed facilitation of habituationwhen compared to pigeons maintained under light-darkcycle. The lower levels of melatonin may act toward a facilitation of habituation. lt was also arsued a possible stress variable due to exposition to two-days ofcontinuous lisht. In this condition the animaIs probablv did not have enough time for adaptation to the new situation of constant light. Further studies are necessary for a precise characterization of those morning-night differences in habituation to sound as expression of a circadian rhvthmiticyMestradoFisiologiaMestre em Ciências Biológica
Changes in daily activity patterns throughout the year in a free-living South American subterranean rodent (<i>Ctenomys coludo</i>)
No full textSilvério JT, Tachinardi P, Langrock R, Kramer-Sunderbrink A, Oda GA, Valentinuzzi VS. Changes in daily activity patterns throughout the year in a free-living South American subterranean rodent (<i>Ctenomys coludo</i>). Mammalian Biology. 2024.Many species of small mammals inhabit subterranean galleries, where daily environmental cycles such as light intensity and temperature, otherwise conspicuous aboveground, are either absent or attenuated. The presence of biological rhythms was investigated in many species of these subterranean habitats. Activity patterns of the subterranean rodent tuco-tuco (Ctenomys coludo), have been studied in laboratory and semi-natural enclosures. Here we extended the description in free-living field conditions. Data from 21 tuco-tucos were collected using animal-borne accelerometers and light-loggers in 4 field campaigns across a year, covering all seasons. Accelerometer data confirmed diurnality in free-living conditions and showed that diurnality does not change throughout the year. However, a significant reduction in general activity was observed during winter. To extract more temporal information from accelerometer data, we used hidden Markov models (HMMs) classifying the data into three distinct activity states roughly corresponding to low-, medium-, and high-intensity activity. While high-intensity activities were day-concentrated and low-intensity was concentrated at night, medium-intensity activity bouts were spread throughout day and night. Furthermore, tuco-tucos displayed significant changes in the time spent in different activity states throughout the year, clarifying that the observed changes in activity levels in winter were due to reduced high activity, allocating more time to medium activities, not rest. Light-logger data confirmed the seasonal variation of daily surface emergence, concentrated in twilight hours during summer and around mid-day in winter, in contrast to general activity, which peaked around mid-day throughout the year. In addition, the HMM analysis clarified that tuco-tucos were mainly in a high-intensity activity state on the surface, which did not change throughout the year. The combination of biologgers and new analytical tools enabled more detailed characterization of activity patterns in free-living animals, expanding the scope of biological clock studies in natural conditions
Circadian phase and intertrial interval interfere with social recognition memory
No full textA modified version of the social habituation/dis-habituation paradigm was employed to examine social recognition memory in Wistar rats during two opposing (active and inactive) circadian phases, using different intertrial intervals (30 and 60 min). Wheel-running activity was monitored continuously to identify circadian phase. To avoid possible masking effects of the light-dark cycle, the rats were synchronized to a skeleton photoperiod, which allowed testing during different circadian phases under identical lighting conditions. In each trial, an infantile intruder was introduced into an adult`s home-cage for a 5-minute interaction session, and social behaviors were registered. Rats were exposed to 5 trials per day for 4 consecutive days: oil days I and 2, each resident was exposed to the same intruder; on days 3 and 4, each resident was exposed to a different intruder in each trial. I he resident`s social investigatory behavior was more intense when different intruders were presented compared to repeated presentation of the same intruder, suggesting social recognition memory. This effect was stronger when the rats were tested during the inactive phase and when the intertrial interval was 60 min, These findings Suggest that social recognition memory, as evaluated in this modified habituation/dis-habituation paradigm, is influenced by the circadian rhythm phase during which testing is performed, and by intertrial interval. (C) 2008 Elsevier Inc. All rights reserved.CAPESCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)FAPESPFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CNPqConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Nocturnal to Diurnal Switches with Spontaneous Suppression of Wheel-Running Behavior in a Subterranean Rodent.
No full textSeveral rodent species that are diurnal in the field become nocturnal in the lab. It has been suggested that the use of running-wheels in the lab might contribute to this timing switch. This proposition is based on studies that indicate feed-back of vigorous wheel-running on the period and phase of circadian clocks that time daily activity rhythms. Tuco-tucos (Ctenomys aff. knighti) are subterranean rodents that are diurnal in the field but are robustly nocturnal in laboratory, with or without access to running wheels. We assessed their energy metabolism by continuously and simultaneously monitoring rates of oxygen consumption, body temperature, general motor and wheel running activity for several days in the presence and absence of wheels. Surprisingly, some individuals spontaneously suppressed running-wheel activity and switched to diurnality in the respirometry chamber, whereas the remaining animals continued to be nocturnal even after wheel removal. This is the first report of timing switches that occur with spontaneous wheel-running suppression and which are not replicated by removal of the wheel
Modeling natural photic entrainment in a subterranean rodent (Ctenomys aff. knighti), the Tuco-Tuco.
No full textSubterranean rodents spend most of the day inside underground tunnels, where there is little daily change in environmental variables. Our observations of tuco-tucos (Ctenomys aff. knighti) in a field enclosure indicated that these animals perceive the aboveground light-dark cycle by several bouts of light-exposure at irregular times during the light hours of the day. To assess whether such light-dark pattern acts as an entraining agent of the circadian clock, we first constructed in laboratory the Phase Response Curve for 1 h light-pulses (1000lux). Its shape is qualitatively similar to other curves reported in the literature and to our knowledge it is the first Phase Response Curve of a subterranean rodent. Computer simulations were performed with a non-linear limit-cycle oscillator subjected to a simple model of the light regimen experienced by tuco-tucos. Results showed that synchronization is achieved even by a simple regimen of a single daily light pulse scattered uniformly along the light hours of the day. Natural entrainment studies benefit from integrated laboratory, field and computational approaches
Form and function of long-range vocalizations in a Neotropical fossorial rodent: the Anillaco Tuco-Tuco (Ctenomys sp.)
No full textThe underground environment poses particular communication challenges for subterranean rodents. Some loud and low-pitched acoustic signals that can travel long distances are appropriate for long-range underground communication and have been suggested to be territorial signals. Long-range vocalizations (LRVs) are important in long-distance communication in Ctenomys tuco-tucos. We characterized the LRV of the Anillaco Tuco-Tuco (Ctenomys sp.) using recordings from free-living individuals and described the behavioral context in which this vocalization was produced during laboratory staged encounters between individuals of both sexes. Long-range calls of Anillaco tuco-tucos are low-frequency, broad-band, loud, and long sounds composed by the repetition of two syllable types: series (formed by notes and soft-notes) and individual notes. All vocalizations were initiated with series, but not all had individual notes. Males were heavier than females and gave significantly lower-pitched vocalizations, but acoustic features were independent of body mass in males. The pronounced variation among individuals in the arrangement and number of syllables and the existence of three types of series (dyads, triads, and tetrads), created a diverse collection of syntactic patterns in vocalizations that would provide the opportunity to encode multiple types of information. The existence of complex syntactic patterns and the description of soft-notes represent new aspects of the vocal communication of Ctenomys. Long-distance vocalizations by Anillaco Tuco-Tucos appear to be territorial signals used mostly in male-male interactions. First, emission of LRVs resulted in de-escalation or space-keeping in male-male and male-female encounters in laboratory experiments. Second, these vocalizations were produced most frequently (in the field and in the lab) by males in our study population. Third, males produced LRVs with greater frequency during male-male encounters compared to male-female encounters. Finally, males appear to have larger home ranges that were more spatially segregated than those of females, suggesting that males may have greater need for long-distance signals that advertise their presence. Due to their apparent rarity, the function and acoustic features of LRV in female tuco-tucos remain inadequately known
