Increased production of 11beta-hydroxysteroid dehydrogenase type 2 in the kidney microsomes of squirrel monkeys (Saimiri spp.).

PubMed

Sadosky, Patti W; Scammell, Jonathan G

2008-04-01

In squirrel monkeys (Saimiri spp.), cortisol circulates at levels much higher than those seen in man and other Old World primates, but squirrel monkeys exhibit no physiologic signs of the mineralocorticoid effects of cortisol. These observations suggest that squirrel monkeys have mechanisms for protection of the mineralocorticoid receptor (MR) from these high levels of cortisol. We previously showed that the serum cortisol to cortisone ratio in these animals is low relative to that in human serum, suggesting that production of the MR protective enzyme, 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2), is increased in squirrel monkeys. Here, we directly evaluate whether increased production of 11beta-HSD2, which inactivates cortisol to cortisone, is a mechanism for protection of MR. In vitro assays showed that 11beta-HSD2 activity in squirrel monkey kidney microsomes was 3 to 7 times higher than that seen in kidney microsomes from pig or rabbit. 11beta-HSD2 protein detected by Western blot analysis was 4 to 9 times greater in squirrel monkey microsomes than in pig or rabbit microsomes. Comparison of the effect of expression of either human or squirrel monkey 11beta-HSD2 on MR transactivation activity showed similar inhibition of MR response to cortisol by both enzymes, indicating that the intrinsic activities of the human and squirrel monkey enzymes are similar. These findings suggest that one mechanism by which squirrel monkeys protect the MR from activation by high cortisol levels in the kidney is by upregulation of 11beta-HSD2 activity through increased production of the enzyme.

Investigation of anti-motion sickness drugs in the squirrel monkey

NASA Technical Reports Server (NTRS)

Cheung, B. S.; Money, K. E.; Kohl, R. L.; Kinter, L. B.

1992-01-01

Early attempts to develop an animal model for anti-motion sickness drugs, using dogs and cats; were unsuccessful. Dogs did not show a beneficial effect of scopolamine (probably the best single anti-motion sickness drug for humans thus far) and the findings in cats were not definitive. The authors have developed an animal model using the squirrel monkey (Saimiri sciureus) of the Bolivian phenotype. Unrestrained monkeys in a small lucite cage were tested in an apparatus that induces motion sickness by combining vertical oscillation and horizontal rotation in a visually unrestricted laboratory environment. Signs of motion sickness were scored using a rating scale. Ten susceptible monkeys (weighing 800-1000 g) were given a total of five tests each, to establish the baseline susceptibility level. Based on the anticholinergic activity of scopolamine, the sensitivity of squirrel monkey to scopolamine was investigated, and the appropriate dose of scopolamine for this species was determined. Then various anti-motion sickness preparations were administered in subsequent tests: 100 ug scopolamine per monkey; 140 ug dexedrine; 50 ug scopolamine plus 70 ug dexedrine; 100 ug scopolamine plus 140 ug dexedrine; 3 mg promethazine; 3 mg promethazine plus 3 mg ephedrine. All these preparations were significantly effective in preventing motion sickness in the monkeys. Ephedrine, by itself, which is marginally effective in humans, was ineffective in the monkeys at the doses tried (0.3-6.0 mg). The squirrel monkey appears to be a good animal model for antimotion sickness drugs. Peripherally acting antihistamines such as astemizole and terfenadine were found to be ineffective, whereas flunarizine, and an arginine vasopressin V1 antagonist, showed significant activity in preventing motion sickness.

Conditioned taste aversion and motion sickness in cats and squirrel monkeys

NASA Technical Reports Server (NTRS)

Fox, Robert A.; Corcoran, Meryl Lee; Brizzee, Kenneth R.

1991-01-01

The relationship between vomiting and conditioned taste aversion was studied in intact cats and squirrel monkeys and in cats and squirrel monkeys in which the area postrema was ablated by thermal cautery. In cats conditioned 7-12 months after ablation of the area postrema, three successive treatments with xylazine failed to produce either vomiting or conditioned taste aversion to a novel fluid. Intact cats, however, vomited and formed a conditioned aversion. In squirrel monkeys conditioned 6 months after ablation of the area postrema, three treatments with lithium chloride failed to produce conditioned taste aversion. Intact monkeys did condition with these treatments. Neither intact nor ablated monkeys vomited or evidenced other signs of illness when injected with lithium chloride. When the same ablated cats and monkeys were exposed to a form of motion that produced vomiting prior to surgery, conditioned taste aversion can be produced after ablation of the area postrema. The utility of conditioned taste aversion as a measure of subemetic motion sickness is discussed by examining agreement and disagreement between identifications of motion sickness by conditioned taste aversion and vomiting. It is suggested that a convincing demonstration of the utility of conditioned taste aversion as a measure of nausea requires the identification of physiological correlates of nausea, and caution should be exercised when attempting to interpret conditioned taste aversion as a measure of nausea.

Spontaneous Cholelithiasis in a Squirrel Monkey (Saimiri sciureus)

PubMed Central

Lieberman, Mia T.; Wachtman, Lynn M.; Marini, Robert P.; Bakthavatchalu, Vasu; Fox, James G.

2016-01-01

A mature female squirrel monkey was noted during routine semiannual examinations to have moderate progressive weight loss. Serum chemistry panels revealed marked increases in hepatic enzyme, bilirubin, and bile salt concentrations and hypoalbuminemia. Abdominal ultrasonography revealed echogenic, shadowing debris in the gallbladder, consistent with cholelithiasis. At necropsy, marked thickening and distension of the gallbladder, cystic duct, and common bile duct was noted, and more than 50 irregularly shaped, black gallstones were removed from the biliary tract. Gallbladder tissue, bile, and gallstones cultured positive for Escherichia coli and Proteus spp., suggesting a brown-pigment gallstone type secondary to a bacterial nidus. Histopathology revealed severe chronic–active diffuse cholecystitis and severe chronic-active hepatic degeneration and necrosis with severe cholestasis. To our knowledge, this report is the first description of spontaneous choleilthiasis in a squirrel monkey. PMID:26884412

Dissecting the mechanisms of squirrel monkey (Saimiri boliviensis) social learning

PubMed Central

Holmes, AN; Williams, LE; Brosnan, SF

2013-01-01

Although the social learning abilities of monkeys have been well documented, this research has only focused on a few species. Furthermore, of those that also incorporated dissections of social learning mechanisms, the majority studied either capuchins (Cebus apella) or marmosets (Callithrix jacchus). To gain a broader understanding of how monkeys gain new skills, we tested squirrel monkeys (Saimiri boliviensis) which have never been studied in tests of social learning mechanisms. To determine whether S. boliviensis can socially learn, we ran “open diffusion” tests with monkeys housed in two social groups (N = 23). Over the course of 10 20-min sessions, the monkeys in each group observed a trained group member retrieving a mealworm from a bidirectional task (the “Slide-box”). Two thirds (67%) of these monkeys both learned how to operate the Slide-box and they also moved the door significantly more times in the direction modeled by the trained demonstrator than the alternative direction. To tease apart the underlying social learning mechanisms we ran a series of three control conditions with 35 squirrel monkeys that had no previous experience with the Slide-box. The first replicated the experimental open diffusion sessions but without the inclusion of a trained model, the second was a no-information control with dyads of monkeys, and the third was a ‘ghost’ display shown to individual monkeys. The first two controls tested for the importance of social support (mere presence effect) and the ghost display showed the affordances of the task to the monkeys. The monkeys showed a certain level of success in the group control (54% of subjects solved the task on one or more occasions) and paired controls (28% were successful) but none were successful in the ghost control. We propose that the squirrel monkeys’ learning, observed in the experimental open diffusion tests, can be best described by a combination of social learning mechanisms in concert; in this

Eye-head coordination during optokinetic stimulation in squirrel monkeys

NASA Technical Reports Server (NTRS)

Kubo, T.; Igarashi, M.; Jensen, D. W.; Homick, J. L.

1981-01-01

Head and eye movements in the yaw plane were recorded during and after optokinetic stimulation in squirrel monkeys. 1) Phasic or tonic head deviations to the side of the ocular quick phase occurred in 94% of total recordings (n = 50) during the perstimulus period, and in 75% of recordings (n = 49) during the poststimulus period. Magnitude of mean head deviation was significantly different between perstimulus and poststimulus periods. 2) Head nystagmus associated with eye nystagmus was consistently observed in seven of nine squirrel monkeys during optokinetic stimulation. Squirrel monkeys are thereby less prone to display head nystagmus than either guinea pigs, pigeons or chickens. 3) Slow phase speeds of coupled head and eye nystagmus were subjected to statistical analysis. A highly significant negative correlation was found between slow phase head and eye speeds. The correlation coefficient was - 0.81 at 60 degrees / sec stimulus (n = 119) and -0.72 at 100 degrees / sec stimulus (n = 131). The gaze speed, calculated by summing the head and eye speeds, was 59.1 plus or minus 6.8 / sec at 60 degrees / sec and 92.2 plus or minus 11.4 at 100 degrees / sec stimulus. There was no significant difference between the gaze speed in a free head condition and the eye speed when the head was fixed.

Isolation and amino acid sequences of squirrel monkey (Saimiri sciurea) insulin and glucagon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Jinghua; Eng, J.; Yalow, R.S.

1990-12-01

It was reported two decades ago that insulin was not detectable in the glucose-stimulated state in Saimiri sciurea, the New World squirrel monkey, by a radioimmunoassay system developed with guinea pig anti-pork insulin antibody and labeled park insulin. With the same system, reasonable levels were observed in rhesus monkeys and chimpanzees. This suggested that New World monkeys, like the New World hystricomorph rodents such as the guinea pig and the coypu, might have insulins whose sequences differ markedly from those of Old World mammals. In this report the authors describe the purification and amino acid sequences of squirrel monkey insulinmore » and glucagon. They demonstrate that the substitutions at B29, B27, A2, A4, and A17 of squirrel monkey insulin are identical with those previously found in another New World primate, the owl monkey (Aotus trivirgatus). The immunologic cross-reactivity of this insulin in their immunoassay system is only a few percent of that of human insulin. It appears that the peptides of the New World monkeys have diverged less from those of the Old World mammals than have those of the New World hystricomorph rodents. The striking improvements in peptide purification and sequencing have the potential for adding new information concerning the evolutionary divergence of species.« less

Antibiotic resistance in Staphylococcus sp. isolated from the vaginal environment of squirrel monkeys (Saimiri spp.) bred ex situ.

PubMed

Donato, Anna C J; Penna, Bruno; Consalter, Angélica; Carvalho, Daniela D; Lilenbaum, Walter; Ferreira, Ana M R

2017-06-01

Squirrel monkeys (Saimiri spp.) have been widely used as animal models; however, the occurrence of Staphylococcus sp in their vaginal microbiota remains to be described. Samples were collected from 175 adult squirrel monkeys to isolate Staphylococcus sp and to test for susceptibility to a panel of nine antimicrobial agents. Isolates with characteristics of the genus Staphylococcus were detected in 95 of 175 samples. Coagulase-negative staphylococci (CoNS) were the most common (95.8%, 91/95) isolates. Resistance to antibiotics was observed in 47.3% (45/95) of isolates. Resistance to tetracycline was observed in 28.5% (26/91), chloramphenicol in 15.4% (14/91), and methicillin in 13.2% (12/91) of CoNS. Coagulase-positive staphylococci were resistant to tetracycline, erythromycin, and methicillin. The presence of Staphylococcus sp in vaginal samples obtained from squirrel monkeys suggests that these animals were in a carrier state. Furthermore, isolating strains resistant to methicillin reinforces the biosafety care of a colony. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Autoshaping and automaintenance of a key-press response in squirrel monkeys.

PubMed

Gamzu, E; Schwam, E

1974-03-01

Following exposure for a minimum of 500 to 600 trials, three of four naive squirrel monkeys eventually pressed a response key, illumination of which always preceded delivery of a food pellet. Three other naive monkeys did not press the key when the pellets were delivered randomly with respect to key illumination. Despite some similarities to autoshaping using pigeons, the data indicate many points of difference when squirrel monkeys are used as subjects. Although key-food pairings were shown to be important in the acquisition of the key-press response, they were ineffective in maintaining the response when either a negative response-reinforcer dependency was introduced, or when there was no scheduled response-reinforcer dependency (fixed trial). Not all demonstrations of autoshaping can be considered to be under the control of those processes that are primarily responsible for the phenomena obtained in pigeons.

Susceptibility of the squirrel monkey to different motion conditions

NASA Technical Reports Server (NTRS)

Fox, Robert A.; Daunton, Nancy G.; Coleman, J.

1991-01-01

The exact stimulus eliciting vomiting in animal studies of motion sickness is difficult to specify because the vestibular stimulation produced by many motion conditions is confounded by voluntary movements with animals. This is an important problem because experiments with animal models of motion sickness can provide useful information about antimotion sickness drugs or the role of neural mechanisms, only when animals are exposed to the same motion stimuli in each experimental session. A series of tests were conducted to determine the susceptibility of 15 adult squirrel monkeys to motion sickness in freely moving and restrained test conditions. Canal stimulation was varied by exposing the monkey in freely moving conditions to varying degrees of angular velocity (60, 90, 120, 150 deg/sec), and in restrained conditions to one angular velocity (150 deg/sec) and to cross-coupling effects of whole-body roll movements during rotation. Otolith stimulation was investigated by using sinusoidal vertical linear acceleration during free movement conditions, and off-vertical rotation and earth-horizontal (BBQ) rotation while restrained. The percentage of freely moving animal vomiting during vertical axis rotation was 27, 93, 86, and 92 for the angular velocities of 60, 90, 120, and 150 deg/sec respectively. None of the monkeys vomited during vertical axis rotation or cross-coupled rotation when restrained. Otolith stimulation appears to be a less provocative stimulus for the squirrel monkey as the percentage of animals vomiting were 13, 0, and 7 for the conditions of free movement during oscillation, restraint during off-vertical, and BBQ rotation respectively. Motion sickness to the point of vomiting occurred regularly only in conditions where self-motion was possible. Such effects could occur because voluntary movement during motion augments vestibular effects by producing self-inflicted cross-coupling, but the failure to elicit vomiting with experimenter-coupling cross

Effect of environmental enrichment devices on behaviors of single- and group-housed squirrel monkeys (Saimiri sciureus)

NASA Technical Reports Server (NTRS)

Spring, S. E.; Clifford, J. O.; Tomko, D. L.

1997-01-01

Squirrel monkeys display an interest in novel places, habituate to new situations, and spend most of their daily activity in the wild in large groups engaging in feeding behaviors over a broad area. Captivity limits these behaviors and consequently may disrupt normal social organizations. In captivity, squirrel monkeys may exhibit stereotypical behaviors that are believed to indicate decreased psychologic well-being. When a monkey's behavior can be made to approach that seen in the wild, and stereotypical behaviors are minimal, it is assumed that psychologic well-being is adequate. Environmental enrichment devices have been used to address the Animal Welfare Act requirement that psychologic well-being of captive nonhuman primates be considered. The purpose of the study reported here was to examine whether various environmental enrichment devices improve the psychologic well-being of captive squirrel monkeys. In the study, we used behavioral observation to quantify the effectiveness of several environmental enrichment devices for reducing stereotypical behaviors in squirrel monkeys housed alone or in groups. Analysis of our results revealed that the environmental enrichment devices did not affect the expression of normal or stereotypical behaviors, but that the type of housing did.

Environmental synchronizers of squirrel monkey circadian rhythms

NASA Technical Reports Server (NTRS)

Sulzman, F. M.; Fuller, C. A.; Moore-Ede, M. C.

1977-01-01

Various temporal signals in the environment were tested to determine if they could synchronize the circadian timing system of the squirrel monkey (Saimiri sciureus). The influence of cycles of light and dark, eating and fasting, water availability and deprivation, warm and cool temperature, sound and quiet, and social interaction and isolation on the drinking and activity rhythms of unrestrained monkeys was examined. In the absence of other time cues, 24-hr cycles of each of these potential synchronizers were applied for up to 3 wk, and the periods of the monkey's circadian rhythms were examined. Only light-dark cycles and cycles of food availability were shown to be entraining agents, since they were effective in determining the period and phase of the rhythmic variables. In the presence of each of the other environmental cycles, the monkey's circadian rhythms exhibited free-running periods which were significantly different from 24 hr with all possible phase relationships between the rhythms and the environmental cycles being examined.

Autoshaping and automaintenance of a key-press response in squirrel monkeys

PubMed Central

Gamzu, Elkan; Schwam, Elias

1974-01-01

Following exposure for a minimum of 500 to 600 trials, three of four naive squirrel monkeys eventually pressed a response key, illumination of which always preceded delivery of a food pellet. Three other naive monkeys did not press the key when the pellets were delivered randomly with respect to key illumination. Despite some similarities to autoshaping using pigeons, the data indicate many points of difference when squirrel monkeys are used as subjects. Although key-food pairings were shown to be important in the acquisition of the key-press response, they were ineffective in maintaining the response when either a negative response-reinforcer dependency was introduced, or when there was no scheduled response-reinforcer dependency (fixed trial). Not all demonstrations of autoshaping can be considered to be under the control of those processes that are primarily responsible for the phenomena obtained in pigeons. PMID:16811749

Integrating histology and MRI in the first digital brain of common squirrel monkey, Saimiri sciureus

NASA Astrophysics Data System (ADS)

Sun, Peizhen; Parvathaneni, Prasanna; Schilling, Kurt G.; Gao, Yurui; Janve, Vaibhav; Anderson, Adam; Landman, Bennett A.

2015-03-01

This effort is a continuation of development of a digital brain atlas of the common squirrel monkey, Saimiri sciureus, a New World monkey with functional and microstructural organization of central nervous system similar to that of humans. Here, we present the integration of histology with multi-modal magnetic resonance imaging (MRI) atlas constructed from the brain of an adult female squirrel monkey. The central concept of this work is to use block face photography to establish an intermediate common space in coordinate system which preserves the high resolution in-plane resolution of histology while enabling 3-D correspondence with MRI. In vivo MRI acquisitions include high resolution T2 structural imaging (300 μm isotropic) and low resolution diffusion tensor imaging (600 um isotropic). Ex vivo MRI acquisitions include high resolution T2 structural imaging and high resolution diffusion tensor imaging (both 300 μm isotropic). Cortical regions were manually annotated on the co-registered volumes based on published histological sections in-plane. We describe mapping of histology and MRI based data of the common squirrel monkey and construction of a viewing tool that enable online viewing of these datasets. The previously descried atlas MRI is used for its deformation to provide accurate conformation to the MRI, thus adding information at the histological level to the MRI volume. This paper presents the mapping of single 2D image slice in block face as a proof of concept and this can be extended to map the atlas space in 3D coordinate system as part of the future work and can be loaded to an XNAT system for further use.

Outbreak of pasteurellosis in captive Bolivian squirrel monkeys (Saimiri boliviensis)

PubMed Central

YOSHINO, Mizuki; SASAKI, Jun; KURAMOCHI, Konomi; IKEZAWA, Mitsutaka; MUKAIZAWA, Natsuko; GORYO, Masanobu

2017-01-01

In September 2012, five Bolivian squirrel monkeys housed in a zoological park died within sequential several days without obvious clinical signs. In a necrospy, one monkey presented swelling of the kidney with multifocal white nodules in the parenchyma, and other two had pulmonary congestion. Histopathologically, multifocal bacterial colonies of gram-negative coccobacillus were found in the sinusoid of the liver in all monkeys examined (Nos.1−4). Additionally, purulent pyelonephritis, pneumonia and disseminated small bacterial colonies in blood vessels were observed. Immunohistochemically, the bacterial colonies from two monkeys were positive for P. multocida capsular serotype D. Based on these findings, these monkeys were diagnosed as septicemia caused by acute P. multocida infection. PMID:28190821

Outbreak of pasteurellosis in captive Bolivian squirrel monkeys (Saimiri boliviensis).

PubMed

Yoshino, Mizuki; Sasaki, Jun; Kuramochi, Konomi; Ikezawa, Mitsutaka; Mukaizawa, Natsuko; Goryo, Masanobu

2017-03-23

In September 2012, five Bolivian squirrel monkeys housed in a zoological park died within sequential several days without obvious clinical signs. In a necrospy, one monkey presented swelling of the kidney with multifocal white nodules in the parenchyma, and other two had pulmonary congestion. Histopathologically, multifocal bacterial colonies of gram-negative coccobacillus were found in the sinusoid of the liver in all monkeys examined (Nos.1-4). Additionally, purulent pyelonephritis, pneumonia and disseminated small bacterial colonies in blood vessels were observed. Immunohistochemically, the bacterial colonies from two monkeys were positive for P. multocida capsular serotype D. Based on these findings, these monkeys were diagnosed as septicemia caused by acute P. multocida infection.

Tail function during arboreal quadrupedalism in squirrel monkeys (Saimiri boliviensis) and tamarins (Saguinus oedipus).

PubMed

Young, Jesse W; Russo, Gabrielle A; Fellmann, Connie D; Thatikunta, Meena A; Chadwell, Brad A

2015-10-01

The need to maintain stability on narrow branches is often presented as a major selective force shaping primate morphology, with adaptations to facilitate grasping receiving particular attention. The functional importance of a long and mobile tail for maintaining arboreal stability has been comparatively understudied. Tails can facilitate arboreal balance by acting as either static counterbalances or dynamic inertial appendages able to modulate whole-body angular momentum. We investigate associations between tail use and inferred grasping ability in two closely related cebid platyrrhines-cotton-top tamarins (Saguinus oedipus) and black-capped squirrel monkeys (Saimiri boliviensis). Using high-speed videography of captive monkeys moving on 3.2 cm diameter poles, we specifically test the hypothesis that squirrel monkeys (characterized by grasping extremities with long digits) will be less dependent on the tail for balance than tamarins (characterized by claw-like nails, short digits, and a reduced hallux). Tamarins have relatively longer tails than squirrel monkeys, move their tails through greater angular amplitudes, at higher angular velocities, and with greater angular accelerations, suggesting dynamic use of tail to regulate whole-body angular momentum. By contrast, squirrel monkeys generally hold their tails in a comparatively stationary posture and at more depressed angles, suggesting a static counterbalancing mechanism. This study, the first empirical test of functional tradeoffs between grasping ability and tail use in arboreal primates, suggests a critical role for the tail in maintaining stability during arboreal quadrupedalism. Our findings have the potential to inform our functional understanding of tail loss during primate evolution. © 2015 Wiley Periodicals, Inc.

Phenotype and Age Differences in Blood Gas Characteristics, Electrolytes, Hemoglobin, Plasma Glucose and Cortisol in Female Squirrel Monkeys

NASA Technical Reports Server (NTRS)

Brizzee, K. R.; Ordy, J. M.; Dunlap, W. P.; Kendrick, R.; Wengenack, T. M.

1988-01-01

Due to its small size, lower cost, tractable nature, successful breeding in captivity and its status near the middle of the primate phylogenetic scale, the squirrel monkey has become an attractive primate model for basic and biomedical research. Although the squirrel monkey now is being used more extensively in many laboratories with diverse interests, only fragmentary reports have been published regarding basic physiological characteristics, or baseline blood reference values of different phenotypes, particularly blood gases, hematology and serum chemical constituents. It is becoming recognized increasingly that these baseline blood reference values are important not only in the care and maintenance of the squirrel monkey, but are critical for assessing normal physiological status, as well as the effects of various experimental treatments. The purpose of this study was to compare differences in blood gases, electrolytes, hematology, blood glucose and cortisol among young and old Bolivian (Roman type) and Colombian (Gothic type) phenotypes of the squirrel monkey.

Adjustments in metabolic heat production by squirrel monkeys exposed to microwaves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adair, E.R.; Adams, B.W.

1982-04-01

The basic fact that microwave exposure can lower metabolic heat production has been previously demonstrated for the mouse by Ho and Edwards (1977) and for the rat by Phillips et al. (1975). The general conclusion drawn from both studies was that the metabolic reduction produced by microwave exposure was dose dependent. The present study extends the investigation into the effects of microwave exposure on metabolic heat production to a primate, the squirrel monkey. When squirrel monkeys are restrained in cool environments, body temperature is regulated by an increase in metabolic heat production. The results of the current study demonstrate thatmore » either brief or prolonged whole-body exposure to a microwave field will cause a reduction of this elevated heat production by an amount directly related to the microwave energy absorbed.« less

Early adaptation to altered gravitational environments in the squirrel monkey

NASA Technical Reports Server (NTRS)

Fuller, C. A.

1985-01-01

The feeding behavior of two squirrel monkeys flown in Spacelab 3 is compared to that of six monkeys exposed to 1.5 G through centrifugation. The monkeys in the centrifugation study were housed unrestrained in cages, maintained at 25 C + or - 1 C, exposed to a 12:12 light/dark cycle, and had unrestrained access to food and water. The Spacelab monkeys were maintained at 26 C, exposed to a 12:12 light/dark cycle and had unlimited food and water. It is observed that the centrifuge rats displayed a change in feeding behavior for 4 days prior to resuming a normal pattern; one Spacelab monkey exhibited a 6 day depression before recover to control levels, and the feeding pattern of the second monkey was not influenced by the environment. It is noted that the effect of an altered dynamic environment is variable on the feeding behavior of individual monkeys.

Polyamines in the lateral vestibular nuclei of the squirrel monkey and their potential role in vestibular compensation

NASA Technical Reports Server (NTRS)

Henley, C.; Igarashi, M.

1993-01-01

Polyamine synthesis increases in response to injurious stimuli including axotomy and denervation. Reduced eye nystagmus and head-deviation have been observed in unilateral labyrinthectomized (UL) guinea pigs treated with an inhibitor of polyamine synthesis, alpha-difluoromethylornithine (DFMO). We quantified polyamines in the lateral vestibular nuclei (LVN) of control and UL squirrel monkeys during the phase of vestibular compensation (VC) and performed an experiment to determine if DFMO reduces nystagmus previously observed in the guinea pig. Polyamines were detected in the LVN of control and UL squirrel monkeys. Putrescine and spermidine increased in the ipsilateral LVN 3 days after UL with no change in the contralateral LVN. No left-right differences were noted in the 5-day post-UL monkey. DFMO reduced nystagmus in a UL squirrel monkey. These findings suggest that polyamines are important in vestibular function and may contribute to nystagmus observed in VC.

On the use of the squirrel monkey in behavorial and pharmacological experiments

PubMed Central

Kelleher, Roger T.; Gill, Charles A.; Riddle, William C.; Cook, Leonard

1963-01-01

We have found the squirrel monkey to be a useful experimental subject for behavioral and pharmacological experiments. This note presents techniques used for housing, feeding, handling, and administering drugs to these small primates. PMID:14031746

Reproducibility and Variation of Diffusion Measures in the Squirrel Monkey Brain, In Vivo and Ex Vivo

PubMed Central

Schilling, Kurt; Gao, Yurui; Stepniewska, Iwona; Choe, Ann S; Landman, Bennett A; Anderson, Adam W

2016-01-01

Purpose Animal models are needed to better understand the relationship between diffusion MRI (dMRI) and the underlying tissue microstructure. One promising model for validation studies is the common squirrel monkey, Saimiri sciureus. This study aims to determine (1) the reproducibility of in vivo diffusion measures both within and between subjects; (2) the agreement between in vivo and ex vivo data acquired from the same specimen and (3) normal diffusion values and their variation across brain regions. Methods Data were acquired from three healthy squirrel monkeys, each imaged twice in vivo and once ex vivo. Reproducibility of fractional anisotropy (FA), mean diffusivity (MD), and principal eigenvector (PEV) was assessed, and normal values were determined both in vivo and ex vivo. Results The calculated coefficients of variation (CVs) for both intra-subject and inter-subject MD were below 10% (low variability) while FA had a wider range of CVs, 2–14% intra-subject (moderate variability), and 3–31% inter-subject (high variability). MD in ex vivo tissue was lower than in vivo (30%–50% decrease), while FA values increased in all regions (30–39% increase). The mode of angular differences between in vivo and ex vivo PEVs was 12 degrees. Conclusion This study characterizes the diffusion properties of the squirrel monkey brain and serves as the groundwork for using the squirrel monkey, both in vivo and ex vivo, as a model for diffusion MRI studies. PMID:27587226

Effects of restricted feeding schedules on circadian organization in squirrel monkeys

NASA Technical Reports Server (NTRS)

Boulos, Z.; Frim, D. M.; Dewey, L. K.; Moore-Ede, M. C.

1989-01-01

Free running circadian rhythms of motor activity, food-motivated lever-pressing, and either drinking (N = 7) or body temperature (N = 3) were recorded from 10 squirrel monkeys maintained in constant illumination with unlimited access to food. Food availability was then restricted to a single unsignaled 3-hour interval each day. The feeding schedule failed to entrain the activity rhythms of 8 monkeys, which continued to free-run. Drinking was almost completely synchronized by the schedule, while body temperature showed a feeding-induced rise superimposed on a free-running rhythm. Nonreinforced lever-pressing showed both a free-running component and a 24-hour component that anticipated the time of feeding. At the termination of the schedule, all recorded variables showed free-running rhythms, but in 3 animals the initial phase of the postschedule rhythms was advanced by several hours, suggesting relative coordination. Of the remaining 2 animals, one exhibited stable entrainment of all 3 recorded rhythms, while the other appeared to entrain temporarily to the feeding schedule. These results indicate that restricted feeding schedules are only a weak zeitgeber for the circadian pacemaker generating free-running rhythms in the squirrel monkey. Such schedules, however, may entrain a separate circadian system responsible for the timing of food-anticipatory changes in behavior and physiology.

Vestibular afferent responses to linear accelerations in the alert squirrel monkey

NASA Technical Reports Server (NTRS)

Somps, Christopher J.; Schor, Robert H.; Tomko, David L.

1994-01-01

The spontaneous activity of 40 otolith afferents and 44 canal afferents was recorded in 4 alert, intact squirrel monkeys. Polarization vectors and response properties of otolith afferents were determined during static re-orientations relative to gravity and during Earth-horizontal, sinusoidal, linear oscillations. Canal afferents were tested for sensitivity to linear accelerations. For regular otolith afferents, a significant correlation between upright discharge rate and sensitivity to dynamic acceleration in the horizontal plane was observed. This correlation was not present in irregular units. The sensitivity of otolith afferents to both static tilts and dynamic linear acceleration was much greater in irregularly discharging units than in regularly discharging units. The spontaneous activity and static and dynamic response properties of regularly discharging otolith afferents were similar to those reported in barbiturate-anesthetized squirrel monkeys. Irregular afferents also had similar dynamic response properties when compared to anesthetized monkeys. However, this sample of irregular afferents in alert animals had higher resting discharge rates and greater sensitivity to static tilts. The majority of otolith polarization vectors were oriented near the horizontal in the plane of the utricular maculae; however, directions of maximum sensitivity were different during dynamic and static testing. Canal afferents were not sensitive to static tilts or linear oscillations of the head.

Use of the feed additive sodium hexametaphosphate to prevent dental calculus in squirrel monkeys (Saimiri spp.).

PubMed

Brady, A G; Williams, L E; Haught, D; Abee, C R

2000-03-01

Dental calculus and associated periodontal disease are serious clinical problems in captive squirrel monkeys. Calculus begins to appear as early as 2 years of age, with subsequent development of periodontal disease, dental abscessation, tooth loss and other sequelae. When used as a feed additive, sodium hexametaphosphate (HMP) retards the growth of calculus on previously cleaned teeth in rhesus monkeys, lemurs, and other species. We wanted to determine whether HMP would reduce dental calculus in squirrel monkeys (Saimiri spp.) whose teeth had not been pre-cleaned. The study animals were divided into two groups. One received a standard diet; the other received an identical diet containing the HMP additive at a concentration effective in other primate and non-primate species that had received dental cleaning prior to treatment with HMP. Teeth were graded for extent of calculus formation at the start of the study and at 3 and 6 months during HMP treatment. We compared the results from the two groups both by total score per animal and according to tooth type (e.g., incisors versus incisors in test and control groups). At the end of 6 months, dental calculus did not differ significantly between the experimental groups. Therefore, we conclude that HMP is ineffective in squirrel monkeys with preexisting dental calculus.

Influence of experimental history on nicotine self-administration in squirrel monkeys.

PubMed

Desai, Rajeev I; Sullivan, Katherine A; Kohut, Stephen J; Bergman, Jack

2016-06-01

Methods for establishing robust long-term self-administration of intravenous (i.v.) nicotine, the primary psychoactive agent in tobacco, are not well-established in laboratory animals. Here, we examine the use of a fading procedure to establish robust and consistent i.v. nicotine self-administration under second-order schedule conditions in squirrel monkeys. First, self-administration behavior was developed in two groups of male squirrel monkeys using a second-order fixed-interval 5-min schedule with fixed-ratio 5 units (FI 5-min (FR5: S)). Comparable performances were maintained by i.v. cocaine (0.032 mg/kg/injection (inj); group A, n = 3) and the combination of food delivery (20-30 % condensed milk) and 0.01 mg/kg/inj i.v. nicotine (group B, n = 3). Subsequently, the concentration of condensed milk was gradually reduced to zero in the second group and self-administration behavior was maintained by i.v. nicotine alone. Next, self-administration of a range of doses of i.v. nicotine (0.001-0.032 mg/kg/inj) and, in additional experiments, the minor tobacco alkaloid anatabine (0.01-0.18 mg/kg/inj) was studied in both groups. Results show that nicotine and anatabine had reinforcing effects in both groups. However, optimal doses of nicotine and anatabine maintained significantly higher rates of i.v. self-administration behavior in subjects trained with the fading procedure than in subjects provided with a history of cocaine-maintained responding. These results illustrate conditions under which robust i.v. nicotine self-administration can be established in squirrel monkeys and the influence of prior experimental history in the expression of reinforcing effects of nicotine and anatabine.

Mapping of enkephalins and adrenocorticotropic hormone in the squirrel monkey brainstem.

PubMed

Duque-Díaz, Ewing; Díaz-Cabiale, Zaida; Narváez, José Angel; Coveñas, Rafael

2017-03-01

An immunocytochemical technique has been used to study for the first time the distribution of fibers and cell bodies containing leucine-enkephalin (leu-enk), methionine-enkephalin (met-enk) or adrenocorticotropic hormone (ACTH) in the whole brainstem of the squirrel monkey Saimiri sciureus. Cell bodies containing leu-enk or met-enk were found in the superior colliculus and the formatio reticularis tegmenti mesencephali, respectively. No immunoreactive cell bodies containing ACTH were observed. Leu-enk-immunoreactive fibers were observed in 40 brainstem nuclei/tracts/regions, fibers containing met-enk were found in 38 brainstem nuclei/tracts/regions and fibers containing ACTH were found in 26 nuclei/tracts/regions. In the latter case, the density of immunoreactive fibers was always low. A high/moderate density of leu-enk- or met-enk-immunoreactive fibers were found in 18 and 16 brainstem nuclei/tracts/regions, respectively. The distribution of immunoreactive fibers containing leu-enk or met-enk was quite similar, with both leu-enk and met-enk observed in 82.5 % of the squirrel monkey brainstem nuclei/tracts/regions. This relationship is less marked for met-enk and ACTH (60.5 %) and even lower for leu-enk and ACTH (52.5 %). In 42.5 % of the nuclei/tracts/regions of the squirrel monkey brainstem (colliculus superior, substantia grisea centralis, nucleus interpeduncularis, nucleus tractus spinalis nervi trigemini, nucleus tractus solitarii, nucleus parabrachialis, formatio reticularis, substantia nigra), we observed fibers containing all three neuropeptides. The widespread distribution reported here suggests that enkephalins and ACTH can be involved in several physiological functions. The distribution of the immunoreactive fibers reported here is quite similar to that previously reported for enkephalins and ACTH in Macaca species and humans.

Effect of Environmental Enrichment on Singly- and Group-Housed Squirrel Monkeys

NASA Technical Reports Server (NTRS)

Spring, Sarah E.; Clifford, James O.; Tomko, David L.; Hargens, Alan R. (Technical Monitor)

1996-01-01

Nonhuman primates display an interest in novel places, habituate to new situations, and spend most of their daily activity in the wild in large groups engaging in feeding behaviors. Captivity changes these behaviors, and disrupts normal social hierarchies. In captivity, animals may exhibit stereotypical behaviors which are thought to indicate decreased psychological well-being (PWB). If an animal's behaviors can be made to approach those seen in the wild, and stereotypical behaviors are minimal it is assumed that PWB is adequate. Environmental enrichment (EE) devices have been used to address the Animal Welfare Act's requirement that the PWB of captive nonhuman primates be considered. The purpose of the present study was to examine whether various EE devices improve the PWB of captive squirrel monkeys. The present study used behavioral observation to quantify the effectiveness of several EE devices in reducing stereotypical behaviors in squirrel monkeys housed singly or in groups. Results showed that the EE devices used did not affect the expression of normal or stereotypical behaviors, but that the type of housing did.

Purification and properties of squirrel monkey (Saimiri sciureus) corticosteroid binding globulins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuhn, R.W.; Weber, C.V.; Siiteri, P.K.

1988-04-05

Corticosteroid binding globulin (CBG), a serum glycoprotein which binds glucocorticoids and progestins with high affinity, is widely distributed throughout the animal world. Although its charge and size characteristics have largely been conserved across species, the authors found the behavior of CBG in squirrel monkey (Saimiri sciureus) serum during fractionation by polyacrylamide gel electrophoresis or Sephadex chromatography was consistent with a molecule about twice the size of that found in most species. To more fully understand the basis for this difference, they purified the protein by sequential affinity and DEAE-Sepharose chromatographies. The final product was obtained in greater than 60% yieldmore » and was found to migrate as a single homogeneous band when examined by electrophoresis. The steroid binding specificity of the purified protein was identical with that of the protein in the starting serum. In contrast to the single protein band observed following electrophoresis under normal conditions, separations in the presence of sodium dodecyl sulfate (SDS) resolved the pure protein into two bands: one at 54,000 daltons and one at 57,000 daltons. Unlike other species, squirrel monkey CBG exists as a dimer in its native state. Antibodies were generated against the purified material and tested for cross-reactivity against the sera from other species by both radioimmunodiffusion and radioimmunoassay techniques. Only serum from titi monkeys was observed to cross-react when examined by radioimmunoassay. Taken together, the results suggest that New World monkey CBG's are distinct from those of other species in both size and immunologic characteristics.« less

Effects of GABA[subscript A] Modulators on the Repeated Acquisition of Response Sequences in Squirrel Monkeys

ERIC Educational Resources Information Center

Campbell, Una C.; Winsauer, Peter J.; Stevenson, Michael W.; Moerschbaecher, Joseph M.

2004-01-01

The present study investigated the effects of positive and negative GABA[subscript A] modulators under three different baselines of repeated acquisition in squirrel monkeys in which the monkeys acquired a three-response sequence on three keys under a second-order fixed-ratio (FR) schedule of food reinforcement. In two of these baselines, the…

Functional characterization of the heterodimeric sweet taste receptor T1R2 and T1R3 from a New World monkey species (squirrel monkey) and its response to sweet-tasting proteins

PubMed Central

Liu, Bo; Ha, Matthew; Meng, Xuan-Yu; Khaleduzzaman, Mohammed; Zhang, Zhe; Li, Xia; Cui, Meng

2012-01-01

The family C G protein-coupled receptor (GPCR) T1R2 and T1R3 heterodimer functions as a broadly acting sweet taste receptor. Perception of sweet taste is a species-dependent physiological process. It has been widely reported that New World monkeys and rodents can not perceive some of the artificial sweeteners and sweet-tasting proteins that can be perceived by humans, apes, and Old World monkeys. Until now, only the sweet receptors of humans, mice and rats have been functionally characterized. Here we report characterization of the sweet taste receptor (T1R2/T1R3) from a species of New World squirrel monkey. Our results show that the heterodimeric receptor of squirrel monkey does not respond to artificial sweeteners aspartame, neotame, cyclamate, saccharin and sweet-tasting protein monellin, but surprisingly, it does respond to thaumatin at high concentrations (>18 μM). This is the first report that New World monkey species can perceive some specific sweet-tasting proteins. Furthermore, the receptor responses to the sweeteners cannot be inhibited by the sweet inhibitor lactisole. We compared the response differences of the squirrel monkey and human receptors and found that the residues in T1R2 determine species-dependent sweet taste toward saccharin, while the residues in either T1R2 or T1R3 are responsible for the sweet taste difference between humans and squirrel monkeys toward monellin. Molecular models indicated that electrostatic properties of the receptors probably mediate the species-dependent response to sweet-tasting proteins. PMID:23000410

Social Behavior in Interacting Squirrel Monkeys with Differential Nutritional and Environmental Histories.

ERIC Educational Resources Information Center

Chappell, Patricia F.

This paper reports an observational study of the effects of handling on the social behavior of squirrel monkeys who received a protein deficient diet. After birth, experimental animals received a low-protein diet for a 6-week period. A subgroup of these animals were handled between 3 and 12 weeks of age. All of the animals interacted (in four…

Food Avoidance Learning in Squirrel Monkeys and Common Marmosets

PubMed Central

Laska, Matthias; Metzker, Karin

1998-01-01

Using a conditioned food avoidance learning paradigm, six squirrel monkeys (Saimiri sciureus) and six common marmosets (Callithrix jacchus) were tested for their ability to (1) reliably form associations between visual or olfactory cues of a potential food and its palatability and (2) remember such associations over prolonged periods of time. We found (1) that at the group level both species showed one-trial learning with the visual cues color and shape, whereas only the marmosets were able to do so with the olfactory cue, (2) that all individuals from both species learned to reliably avoid the unpalatable food items within 10 trials, (3) a tendency in both species for quicker acquisition of the association with the visual cues compared with the olfactory cue, (4) a tendency for quicker acquisition and higher reliability of the aversion by the marmosets compared with the squirrel monkeys, and (5) that all individuals from both species were able to reliably remember the significance of the visual cues, color and shape, even after 4 months, whereas only the marmosets showed retention of the significance of the olfactory cues for up to 4 weeks. Furthermore, the results suggest that in both species tested, illness is not a necessary prerequisite for food avoidance learning but that the presumably innate rejection responses toward highly concentrated but nontoxic bitter and sour tastants are sufficient to induce robust learning and retention. PMID:10454364

Emergence of Cryptosporidium hominis Monkey Genotype II and Novel Subtype Family Ik in the Squirrel Monkey (Saimiri sciureus) in China.

PubMed

Liu, Xuehan; Xie, Na; Li, Wei; Zhou, Ziyao; Zhong, Zhijun; Shen, Liuhong; Cao, Suizhong; Yu, Xingming; Hu, Yanchuan; Chen, Weigang; Peng, Gangneng

2015-01-01

A single Cryptosporidium isolate from a squirrel monkey with no clinical symptoms was obtained from a zoo in Ya'an city, China, and was genotyped by PCR amplification and DNA sequencing of the small-subunit ribosomal RNA (SSU rRNA), 70-kDa heat shock protein (HSP70), Cryptosporidium oocyst wall protein, and actin genes. This multilocus genetic characterization determined that the isolate was Cryptosporidium hominis, but carried 2, 10, and 6 nucleotide differences in the SSU rRNA, HSP70, and actin loci, respectively, which is comparable to the variations at these loci between C. hominis and the previously reported monkey genotype (2, 3, and 3 nucleotide differences). Phylogenetic studies, based on neighbor-joining and maximum likelihood methods, showed that the isolate identified in the current study had a distinctly discordant taxonomic status, distinct from known C. hominis and also from the monkey genotype, with respect to the three loci. Restriction fragment length polymorphisms of the SSU rRNA gene obtained from this study were similar to those of known C. hominis but clearly differentiated from the monkey genotype. Further subtyping was performed by sequence analysis of the gene encoding the 60-kDa glycoprotein (gp60). Maximum homology of only 88.3% to C. hominis subtype IdA10G4 was observed for the current isolate, and phylogenetic analysis demonstrated that this particular isolate belonged to a novel C. hominis subtype family, IkA7G4. This study is the first to report C. hominis infection in the squirrel monkey and, based on the observed genetic characteristics, confirms a new C. hominis genotype, monkey genotype II. Thus, these results provide novel insights into genotypic variation in C. hominis.

Ultrastructural Analysis of the Cristae Ampullares in the Squirrel Monkey (Saimiri sciureus)*

PubMed Central

Lysakowski, Anna; Goldberg, Jay M.

2008-01-01

Type I hair cells outnumber type II hair cells (HCs) in squirrel monkey (Saimiri sciureus) cristae by a nearly 3:1 ratio. Associated with this type I HC preponderance, calyx fibers make up a much larger fraction of the afferent innervation than in rodents (Fernández et al., 1995). To study how this affected synaptic architecture, we used disector methods to estimate various features associated with type I and type II HCs in central (CZ) and peripheral (PZ) zones of monkey cristae. Each type I HC makes, on average, 5–10 ribbon synapses with the inner face of a calyx ending. Inner-face synapses outnumber those on calyx outer faces by a 40:1 ratio. Expressed per afferent, there are, on average, 15 inner-face ribbon synapses, 0.38 outer-face ribbons and 2.6 efferent boutons on calyx-bearing endings. Calyceal invaginations per type I HC range from 19 in CZ to 3 in PZ. For type II HCs, there are many more ribbons and afferent boutons in PZ than in CZ, whereas efferent innervation is relatively uniform throughout the neuroepithelium. Despite outer-face ribbons being more numerous in chinchilla than in squirrel monkey, afferent discharge properties are similar (Lysakowski et al., 1995), reinforcing the importance of inner-face ribbons in synaptic transmission. Comparisons across mammalian species suggest the prevalence of type I HCs is a primate characteristic, rather than an arboreal lifestyle adaptation. Unlike cristae, type II HCs predominate in monkey maculae. Differences in hair-cell counts may reflect the stimulus magnitudes handled by semicircular canals and otolith organs. PMID:18729176

The squirrel monkey as a candidate for space flight

NASA Technical Reports Server (NTRS)

Brizzee, K. R.; Ordy, J. M.; Kaack, B.

1977-01-01

Because of its size and other unique diurnal-primate characteristics, the squirrel monkey is used in: (1) actual bioflight missions, (2) in laboratory tests designed to clarify the risks to man during launch and recovery as well as in hazardous spaceflight environments; and (3) in the acquisition of data on unknown risks encountered in long duration space exploration. Pertinent data concerning samiri sciureus as described in published and unpublished reports are summarized. Topics include: taxonomy, ethology, life history, sensory-learning-motor capabilities in primate perspective, anatomy and physiology (including homeostatic adaptation to stress), susceptibility to environmental hazards, reproduction, care and clinical management, and previous use in aerospace biomedical research.

Background and stimulus-induced patterns of high metabolic activity in the visual cortex (area 17) of the squirrel and macaque monkey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Humphrey, A.L.; Hendrickson, A.E.

1983-02-01

The authors have used 2-deoxy-D-(/sup 14/C)glucose (2-DG) autoradiography and cytochrome oxidase histochemistry to examine background and stimulus-induced patterns of metabolic activity in monkey striate cortex. In squirrel monkeys (Saimiri sciureus) that binocularly or monocularly viewed diffuse white light or binocularly viewed bars of many orientations and spatial frequencies, 2-DG consumption was not uniform across the cortex but consisted of regularly spaced radial zones of high uptake. The cytochrome oxidase stain in these animals also revealed patches of high metabolism which coincided with the 2-DG patches. Squirrel monkeys binocularly viewing vertical stripes showed parallel bands of increased 2-DG uptake in themore » cortex, while the cytochrome label in these animals remained patchy. In macaque (Macaca nemestrina) monkeys, binocular stimulation with many orientations and spatial frequencies produced radial zones of high 2-DG uptake. When viewed tangentially, these zones formed a dots-in-rows pattern with a spacing of 350 X 500 microns; cytochrome oxidase staining produced an identical pattern. Macaca differed from Saimiri in that monocular stimulation labeled alternate rows. These results indicate that there are radial zones of high background metabolism across squirrel and macaque monkey striate cortex. In Saimiri these zones do not appear to be related to an eye dominance system, while in Macaca they do. The presence of these zones of high metabolism may complicate the interpretation of 2-DG autoradiographs that result from specific visual stimuli.« less

The VALiDATe29 MRI Based Multi-Channel Atlas of the Squirrel Monkey Brain.

PubMed

Schilling, Kurt G; Gao, Yurui; Stepniewska, Iwona; Wu, Tung-Lin; Wang, Feng; Landman, Bennett A; Gore, John C; Chen, Li Min; Anderson, Adam W

2017-10-01

We describe the development of the first digital atlas of the normal squirrel monkey brain and present the resulting product, VALiDATe29. The VALiDATe29 atlas is based on multiple types of magnetic resonance imaging (MRI) contrast acquired on 29 squirrel monkeys, and is created using unbiased, nonlinear registration techniques, resulting in a population-averaged stereotaxic coordinate system. The atlas consists of multiple anatomical templates (proton density, T1, and T2* weighted), diffusion MRI templates (fractional anisotropy and mean diffusivity), and ex vivo templates (fractional anisotropy and a structural MRI). In addition, the templates are combined with histologically defined cortical labels, and diffusion tractography defined white matter labels. The combination of intensity templates and image segmentations make this atlas suitable for the fundamental atlas applications of spatial normalization and label propagation. Together, this atlas facilitates 3D anatomical localization and region of interest delineation, and enables comparisons of experimental data across different subjects or across different experimental conditions. This article describes the atlas creation and its contents, and demonstrates the use of the VALiDATe29 atlas in typical applications. The atlas is freely available to the scientific community.

Impact of stimulus format and reward value on quantity discrimination in capuchin and squirrel monkeys.

PubMed

Gazes, Regina Paxton; Billas, Alison R; Schmitt, Vanessa

2018-03-01

Quantity discrimination abilities are seen in a diverse range of species with similarities in performance patterns, suggesting common underlying cognitive mechanisms. However, methodological factors that impact performance make it difficult to draw broad phylogenetic comparisons of numerical cognition across studies. For example, some Old World monkeys selected a higher quantity stimulus more frequently when choosing between inedible (pebbles) than edible (food) stimuli. In Experiment 1 we presented brown capuchin (Cebus [Sapajus] paella) and squirrel monkeys (Saimiri sciureus) with the same two-choice quantity discrimination task in three different stimulus conditions: edible, inedible, and edible replaced (in which choice stimuli were food items that stood in for the same quantity of food items that were given as a reward). Unlike Old World monkeys, capuchins selected the higher quantity stimulus more in the edible condition and squirrel monkeys showed generally poor performance across all stimulus types. Performance patterns suggested that differences in subjective reward value might motivate differences in choice behavior between and within species. In Experiment 2 we manipulated the subjective reinforcement value of the reward by varying reward type and delay to reinforcement and found that delay to reinforcement had no impact on choice behavior, while increasing the value of the reward significantly improved performance by both species. The results of this study indicate that species presented with identical tasks may respond differently to methodological factors such as stimulus and reward types, resulting in significant differences in choice behavior that may lead to spurious suggestions of species differences in cognitive abilities.

Effect of prenatal ionizing radiation on the visual cortex and hippocampus of newborn squirrel monkeys. [/sup 60/Co

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brizzee, K.R.; Ordy, J.M.; Kaack, M.B.

1980-09-01

Five squirrel monkeys were exposed to 200 rads whole-body ionizing irradiation (/sup 60/Co) at 0.4 rads per second on approximately the seventy-fifth day of gestation, and six squirrel monkeys were sham-irradiated. The mean cortical depth and the mean number of neurons per mm/sup 3/ in the visual cortex was less in irradiated animals than in controls, but the differences were not statistically significant. The mean number of glial cells in this cortical region was significantly lower in the irradiated animals. In the hippocampus, the depth of the stratum oriens and the combined depth of the strata radiatum, lacunosum, and molecularemore » were significantly less in irradiated than in control animals. Canonical correlations provided statistical evidence for greater radiation vulnerability of the hippocampus compared to motor and visual areas of the cerebral cortex.« less

Effects of sulfate aerosols upon cardiopulmonary function in squirrel monkeys (final report). (Second year final report: effects of nitrate and /or sulfate aerosols upon cardiopulmonary function)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greenberg, H.L.; Avol, E.L.; Bailey, R.M.

1977-06-24

Squirrel monkeys were exposed to nominal concentrations of 2.5 mg/cu m of the following generated aerosols: zinc ammonium sulfate at both low (40%) and high (85%) nominal relative humidities, histamine diphosphate at low relative humidity, and ammonium bisulfate at low relative humidity. There were few statistically significant changes in oscillatory resistance, however, several trends toward increased resistance were present. Additional studies were performed using two different aerosol nebulizers to produce histamine diphosphate particles in two distinct size distributions, an order of magnitude different in size. These results, supported by data collected during sulfur dioxide exposures of squirrel monkeys, are usedmore » to discuss the suitability of Saimiri sciureus as a sensitive indicator species and oscillatory resistance as a valuable measurement of proximal airway changes. Development of the esophageal balloon technique as a means of measuring compliance and resistance in the unanesthetized squirrel monkey is discussed.« less

Background and stimulus-induced patterns of high metabolic activity in the visual cortex (area 17) of the squirrel and macaque monkey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Humphrey, A.L.; Hendrickson, A.E.

1983-02-01

We have used 2-deoxy-D-(/sup 14/C)glucose (2-DG) autoradiography and cytochrome oxidase histochemistry to examine background and stimulus-induced patterns of metabolic activity in monkey striate cortex. In squirrel monkeys (Saimiri sciureus) that binocularly or monocularly viewed diffuse white light or binocularly viewed bars of many orientations and spatial frequencies, 2-DG consumption was not uniform across the cortex but consisted of regularly spaced radial zones of high uptake. The zones extended through all laminae except IVc beta and, when viewed tangentially, formed separate patches 500 microns apart. The cytochrome oxidase stain in these animals also revealed patches of high metabolism which coincided withmore » the 2-DG patches. Squirrel monkeys binocularly viewing vertical stripes showed parallel bands of increased 2-DG uptake in the cortex, while the cytochrome label in these animals remained patchy. When monkeys were kept in the dark during 2-DG exposure, 2-DG-labeled patches were not seen but cytochrome oxidase-positive patches remained. In macaque (Macaca nemestrina) monkeys, binocular stimulation with many orientations and spatial frequencies produced radial zones of high 2-DG uptake in layers I to IVa and VI. When viewed tangentially, these zones formed a dots-in-rows pattern with a spacing of 350 X 500 microns; cytochrome oxidase staining produced an identical pattern. Macaca differed from Saimiri in that monocular stimulation labeled alternate rows. These results indicate that there are radial zones of high background metabolism across squirrel and macaque monkey striate cortex. In Saimiri these zones do not appear to be related to an eye dominance system, while in Macaca they do. The presence of these zones of high metabolism may complicate the interpretation of 2-DG autoradiographs that result from specific visual stimuli.« less

Nectin-4 Interactions Govern Measles Virus Virulence in a New Model of Pathogenesis, the Squirrel Monkey (Saimiri sciureus).

PubMed

Delpeut, Sébastien; Sawatsky, Bevan; Wong, Xiao-Xiang; Frenzke, Marie; Cattaneo, Roberto; von Messling, Veronika

2017-06-01

In addition to humans, only certain nonhuman primates are naturally susceptible to measles virus (MeV) infection. Disease severity is species dependent, ranging from mild to moderate for macaques to severe and even lethal for certain New World monkey species. To investigate if squirrel monkeys ( Saimiri sciureus ), which are reported to develop a course of disease similar to humans, may be better suited than macaques for the identification of virulence determinants or the evaluation of therapeutics, we infected them with a green fluorescent protein-expressing MeV. Compared to cynomolgus macaques ( Macaca fascicularis ) infected with the same virus, the squirrel monkeys developed more-severe immunosuppression, higher viral load, and a broader range of clinical signs typical for measles. In contrast, infection with an MeV unable to interact with the epithelial receptor nectin-4, while causing immunosuppression, resulted in only a mild and transient rash and a short-lived elevation of the body temperature. Similar titers of the wild-type and nectin-4-blind MeV were detected in peripheral blood mononuclear cells and lymph node homogenates, but only the wild-type virus was found in tracheal lavage fluids and urine. Thus, our study demonstrates the importance of MeV interactions with nectin-4 for clinical disease in the new and better-performing S. sciureus model of measles pathogenesis. IMPORTANCE The characterization of mechanisms underlying measles virus clinical disease has been hampered by the lack of an animal model that reproduces the course of disease seen in human patients. Here, we report that infection of squirrel monkeys ( Saimiri sciureus ) fulfills these requirements. Comparative infection with wild-type and epithelial cell receptor-blind viruses demonstrated the importance of epithelial cell infection for clinical disease, highlighting the spread to epithelia as an attractive target for therapeutic strategies. Copyright © 2017 American Society for

Recovery of the vomiting reflex following area postrema ablation in squirrel monkeys

NASA Technical Reports Server (NTRS)

Elfar, S.; Brizzee, Kenneth R.; Fox, Robert A.; Corcoran, Meryl Lee; Daunton, Nancy G.; Coleman, J.

1991-01-01

The role of the area postrema (AP) in motion-induced emesis was re-assessed recently in several different species. In a few of these studies, the role of the AP in motion-induced conditioned taste aversion (CTA) was also addressed. The purpose was to extend this comparative study to the squirrel monkey, to evaluate further the role of AP in vomiting, and to investigate the dynamics of the recovery process. The AP was ablated bilaterally in 7 motion-susceptible squirrel monkeys which previously had been characterized in terms of their responses to various motion sickness-inducing stimuli. After recovery from surgery all animals were tested at 30-day intervals for a period of 11 months to determine the effects of AP ablations on susceptibility to the same sickness-inducing conditions. In addition, the effectiveness of motion in preducing CTA was evaluated. All pre-ablation motion tests involved stimulation for 30 min., while post-lesion tests were 60 min., in duration. All animals showed significant increases in latencies to vomiting after AP ablations. However, the latencies tended to decrease with time after ablation. All but one animal vomited on at least one of the 10 motion tests occurring after ablation of AP. In addition, CTA was produced by motion used in the conditioning sessions. These results suggest that structures other than AP, and processes other that those mediated through AP, may play an important role in motion-induced emesis.

Temperature and behavioral responses of squirrel monkeys to 2Gz acceleration

NASA Technical Reports Server (NTRS)

Fuller, C. A.; Tremor, J.; Connolly, J. P.; Williams, B. A.

1982-01-01

This study examines the responses of squirrel monkeys to acute +2Gz exposure. Body temperature responses of loosely restrained animals were recorded via a thermistor in the colon. Behavioral responses were recorded by video monitoring. After baseline recording at 1G, monkeys were exposed to 2G for 60 min. The body temperature started to fall within 10 min of the onset of centrifugation and declined an average of 1.4 C in 60 min. This is in contrast to a stable body temperature during the control period. Further, after a few minutes at 2G, the animals became drowsy and appeared to fall asleep. During the control period, however, they were alert and continually shifting their gaze about the cage. Thus, primates are susceptible to hypergravic fields in the +Gz orientation. The depression in primate body temperature was consistent and significant. Further, the observed drowsiness in this study has significant ramifications regarding alertness and performance in man.

The susceptibility of rhesus monkeys to motion sickness

NASA Technical Reports Server (NTRS)

Corcoran, Meryl L.; Daunton, Nancy G.; Fox, Robert A.

1990-01-01

The susceptibility of rhesus monkeys to motion sickness was investigated using test conditions that are provocative for eliciting motion sickness in squirrel monkeys. Ten male rhesus monkeys and ten male Bolivian squirrel monkeys were rotated in the vertical axis at 150 deg/s for a maximum duration of 45 min. Each animal was tested in two conditions, continuous rotation and intermittent rotation. None of the rhesus monkeys vomited during the motion tests but all of the squirrel monkeys did. Differences were observed between the species in the amount of activity that occurred during motion test, with the squirrel monkeys being significantly more active than the rhesus monkeys. These results, while substantiating anecdotal reports of the resistance of rhesus monkeys to motion sickness, should be interpreted with caution because of the documented differences that exist between various species with regard to stimuli that are provocative for eliciting motion sickness.

Effects of single-use and group-use enrichment on stereotypy and intragroup aggressive and affiliative behaviors of a social group of squirrel monkeys (Saimiri sciureus) at the Singapore Zoo.

PubMed

Sha, John; Han, Sharleen; Marlena, Diana; Kee, Julienne

2012-01-01

Four food-based enrichment devices were used to test the effects of single-use and group-use enrichment devices on stereotypy, intragroup aggression, and affiliation in a compatible group of 5 squirrel monkeys (Saimiri sciureus). All enrichment devices were found to reduce overall stereotypic behavior from baseline levels (without enrichment). The occurrence of stereotypic behavior differed between individual squirrel monkeys with an adult female showing the highest level of stereotypic behavior. This individual also showed the highest usage of enrichment devices, and stereotypic behavior was significantly reduced when enrichment was applied. The occurrence of stereotypic behavior did not differ significantly between single-use and group-use enrichment treatments. Higher intragroup aggression and lower affiliation were observed during the provision of enrichment compared with baseline levels. However, aggressive behavior was higher and affiliation lower during single-use enrichment compared with group-use enrichment. The results of this study showed that enrichment had positive effects on alleviating stereotypic behavior in a group of zoo-housed squirrel monkeys and such effects were similar when group-use and single-use enrichment devices were used, but with variations between individuals. The application of enrichment, particularly single-use enrichment devices, elicited higher levels of aggression within the group and lower affiliation. Such effects could curtail the benefits of original enrichment goals as higher intragroup aggression could lead to higher stress levels within the group. When food-based enrichment for social nonhuman primates is implemented, the most appropriate methods to alleviate undesirable behavior without additional negative effects such as increased group aggression should be considered.

Cocaine self-administration under variable-dose schedules in squirrel monkeys.

PubMed

Panlilio, Leigh V; Thorndike, Eric B; Schindler, Charles W

2006-06-01

Squirrel monkeys self-administered cocaine under a variable-dose schedule, with the dose varied from injection to injection. As in earlier studies with rats, post-injection pauses varied as a monotonic function of dose, allowing a cocaine dose-effect curve to be obtained during each session. These curves were shifted by pretreatment with dopamine antagonists, demonstrating that this procedure may provide an efficient means of evaluating treatments that affect drug self-administration. However, drug intake eventually became "dysregulated" after extensive training (100-300 sessions), with relatively short pauses following all doses. Dose-sensitivity was restored by adding a 60-s timeout period after each injection, suggesting that dysregulation occurred because the monkeys developed a tendency to self-administer another injection before the previous injection had been adequately distributed. Finally, when the response requirement under the variable-dose schedule was increased from 1 to 10, both the post-injection pause and the rate of responding following the pause ("run rates") were found to vary with dose. The dose-dependency of run rates suggests that post-injection pauses reflect not only motivational factors, such as satiety, but also the direct effects of cocaine on leverpressing.

Metabolism of 1,2,3,4-, 1,2,3,5-, and 1,2,4,5-tetrachlorobenzene in the squirrel monkey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwartz, H.; Chu, I.; Villeneuve, D.C.

1987-01-01

The metabolism of three tetrachlorobenzene isomers (TeCB) was investigated in the squirrel monkey. The animals were administered orally 6 single doses of /sup 14/C-labeled 1,2,3,4-, 1,2,4,5-, or 1,2,3,5-tetrachlorobenzene over a 3-wk period at levels ranging from 50 to 100 mg/kg body weight (b.w) and kept in individual metabolism cages to collect urine and feces for radioassay. Approximately 38% (1,2,3,4-TeCB), 36% (1,2,3,5-TeCB), and 18% (1,2,4,5-TeCB) of the doses were excreted respectively in the feces 48 h post administration. In monkeys dosed with 1,2,3,4-TeCB, unchanged compound accounted for 50% of the fecal radioactivity. Unchanged compound accounted for more than 50% of themore » fecal radioactivity found in the monkeys dosed with 1,2,3,5-TeCB. The fecal metabolites were identified in both groups. No metabolites were detected in the feces of monkeys dosed with 1,2,4,5-TeCB. While the fecal route represented the major route of excretion for 1,2,3,4-TeCB, the other two isomers were eliminated exclusively in the feces. The above data in the squirrel monkey are different from those obtained with the rat and the rabbit, and demonstrate the different metabolic pathways for the isomers.« less

Studies on the discriminative stimulus properties of ethanol in squirrel monkeys.

PubMed

York, J L; Bush, R

1982-01-01

Eight male squirrel monkeys were trained to use the pharmacological effects of ethanol [orally via gastric intubation 1600 mg/kg (IG), in normal saline] versus those produced by equivolume saline as discriminative stimuli in an operant conditioning (bar pressing) procedure in which the availability of banana-flavored food pellets was made contingent upon the drug condition of the animal (ethanol SD, saline S delta for four monkeys; saline SD, ethanol S delta for the other four monkeys). Test doses of 7.5 mg/kg pentobarbital IG and 80 mg/kg barbital IG closely mimicked the cue properties of ethanol, while doses of morphine sulfate (5.0-20 mg/kg IG) failed to elicit ethanol-appropriate responding. Other ethanolic beverages containing 1600 mg/kg ethanol in the same volume as the training dose, and found to mimic the cue properties of pure ethanol were bourbon, gin, beer, vodka, and red wine. The single test dose of cognac, scotch, and tequila elicited responding different from that of the training dose of ethanol. Thus, the pharmacological effects of ethanolic beverages containing the same dose of ethanol (1600 mg/kg) may be noticeably different to some subjects. Blood levels of ethanol produced by the different beverages may be an important variable. There was no differential effect of the beverages upon free-feeding behavior of the monkeys at the time of testing. Ethanol preference tests conducted at the end of the study (i.e., after nearly 2 years of drug discrimination training) indicated that the assignment of ethanol as the condition under which food pellets were available (SD condition) moderately increased the ethanol preference of those subjects as compared to monkeys for whom ethanol had served as the S delta condition.

Motion sickness elicited by passive rotation in squirrel monkeys

NASA Technical Reports Server (NTRS)

Daunton, Nancy G.; Fox, Robert A.

1991-01-01

Current theory and recent evidence suggest that motion sickness occurs under conditions of sensory input in which the normal motor programs for producing eye, head, and body movements are not functionally effective, i.e. under conditions in which there are difficulties in maintaining posture and controlling eye movements. Conditions involving conflicting or inconsistent visual-vestibular (VV) stimulation should thus result in greater sickness rates since the existing motor programs do not produce effective control of eye-head-body movements under such conditions. It is felt that the relationship of postural control to motion sickness is an important one and one often overlooked. The results are reported which showed that when postural requirements were minimized by fully restraining squirrel monkeys during hypogravity parabolic flight, no animals became motion sick, but over 80 percent of the same 11 animals became sick if they were unrestrained and maintained control of their posture.

Renal response to seven days of lower body positive pressure in the squirrel monkey

NASA Technical Reports Server (NTRS)

Churchill, Susanne; Pollock, David M.; Natale, Mary Ellen; Moore-Ede, Martin C.

1987-01-01

As a ground-based model for weightlessness, the response of the chair-trained squirrel monkey to lower body positive pressure (LBPP) was evaluated in a length of study similar to a typical Space Shuttle mission (7 days). Results were compared to time control experiments that included chair-sitting without exposure to LBPP. Chronic exposure to LBPP results in an acute diuretic and natriuretic response independent of changes in plasma aldosterone concentrations and produces a chronic reduction in fluid volume lasting the duration in the stimulus.

Isolation and molecular characterization of Toxoplasma gondii in a colony of captive black-capped squirrel monkeys (Saimiri boliviensis).

PubMed

Pardini, L; Dellarupe, A; Bacigalupe, D; Quiroga, M A; Moré, G; Rambeaud, M; Basso, W; Unzaga, J M; Schares, G; Venturini, M C

2015-12-01

Toxoplasmosis is commonly asymptomatic; however, it can be a fatal multisystemic disease in some animal species, such as New World monkeys. An outbreak of acute fatal toxoplasmosis was reported in a colony of black-capped squirrel monkeys (Saimiri boliviensis) from the zoo of La Plata, Argentina. Post-mortem examination of two monkeys revealed macroscopical and microscopical lesions compatible with acute toxoplasmosis. The presence of Toxoplasma gondii was confirmed by immunohistochemistry on monkey tissues, bioassay in mice and PCR using the specific primers B22-B23. By PCR-RFLP analysis, T. gondii isolated in mice, deriving from both monkeys, showed the same restriction pattern, with most markers showing a type III restriction pattern, except for C22-8 (type II) and C29-2 (type I). To our knowledge this is the first report of fatal toxoplasmosis in S. boliviensis caused by a non-canonical or atypical genotype of T. gondii. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Individual differences in zoo-housed squirrel monkeys' (Saimiri sciureus) reactions to visitors, research participation, and personality ratings.

PubMed

Polgár, Zita; Wood, Lara; Haskell, Marie J

2017-05-01

Understanding individual differences in captive squirrel monkeys is a topic of importance both for improving welfare by catering to individual needs, and for better understanding the results and implications of behavioral research. In this study, 23 squirrel monkeys (Saimiri sciureus), housed in an environment that is both a zoo enclosure and research facility, were assessed for (i) the time they spent by an observation window under three visitor conditions: no visitors, small groups, and large groups; (ii) their likelihood of participating in voluntary research; and (iii) zookeepers, ratings of personality. A Friedman's ANOVA and Wilcoxon post-hoc tests comparing mean times found that the monkeys spent more time by the window when there were large groups present than when there were small groups or no visitors. Thus, visitors do not seem to have a negative effect and may be enriching for certain individuals. Through GLMM and correlational analyses, it was found that high scores on the personality trait of playfulness and low scores on cautiousness, depression, and solitude were significant predictors of increased window approach behavior when visitors were present. The GLMM and correlational analyses assessing the links between personality traits and research participation found that low scores of cautiousness and high scores of playfulness, gentleness, affection, and friendliness, were significant predictors. The implications of these results are discussed in relation to selection bias and its potential confounding effect on cognitive studies with voluntary participation. © 2017 Wiley Periodicals, Inc.

Effect of physical exercise prelabyrinthectomy on locomotor balance compensation in the squirrel monkey

NASA Technical Reports Server (NTRS)

Igarashi, M.; Ohashi, K.; Yoshihara, T.; MacDonald, S.

1989-01-01

This study examines the effectiveness of physical exercise, during a prepathology state, on locomotor balance compensation after subsequent unilateral labyrinthectomy in squirrel monkeys. An experimental group underwent 3 hr. of daily running exercise on a treadmill for 3 mo. prior to the surgery, whereas a control group was not exercised. Postoperatively, the locomotor balance function of both groups was tested for 3 mo. There was no significant difference in gait deviation counts in the acute phase of compensation. However, in the chronic compensation maintenance phase, the number of gait deviation counts was fewer in the exercise group, which showed significantly better performance stability.

Susceptibility of cat and squirrel monkey to motion sickness induced by visual stimulation: Correlation with susceptibility to vestibular stimulation

NASA Technical Reports Server (NTRS)

Daunton, N. G.; Fox, R. A.; Crampton, G. H.

1984-01-01

Experiments in which the susceptibility of both cats and squirrel monkeys to motion sickness induced by visual stimulation are documented. In addition, it is shown that in both species those individual subjects most highly susceptible to sickness induced by passive motion are also those most likely to become motion sick from visual (optokinetic) stimulation alone.

Effect of pulsed 5. 62 ghz microwaves on squirrel monkeys (saimiri sciureus) performing a repeated acquisition task. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knepton, J.; de Lorge, J.

1983-01-28

Navy personnel assigned to perform duties in the vicinity of microwave irradiating devices are subject to possible hazards if the irradiation is of adequate intensity and frequency. Data are of critical need to establish safety standards for human exposure to microwaves. In an effort to provide such information squirrel monkeys were trained on a task that required learning and were subsequently irradiated with microwaves while they performed the task. Four male squirrel monkeys trained to perform a repeated learning task demonstrated performance decay while being exposed to pulsed 5.62 GHz microwave radiation in the far-field situation at power densities ofmore » 38 and 46 mW/sq cm, but there was only slight learning impairment. There was little, if any, effect on learning or performance at 17 and 32 mW/sq cm. The performance effect became evident when the monkey's colonic temperature increased 1 C or more above the small increases that occurred during sham exposure. There was no evidence of either thermal or behavioral adaption, nor were there indications of lasting microwave effects. Specific absorption rate (SAR) values, obtained from saline and tissue-simulating models, coupled with the performance decay finding at 38 and 46 mW/sq cm indicate that special attention should be given to exposures of the head and extremities when establishing safety standards for human exposure.« less

A 3D high resolution ex vivo white matter atlas of the common squirrel monkey (saimiri sciureus) based on diffusion tensor imaging

NASA Astrophysics Data System (ADS)

Gao, Yurui; Parvathaneni, Prasanna; Schilling, Kurt G.; Wang, Feng; Stepniewska, Iwona; Xu, Zhoubing; Choe, Ann S.; Ding, Zhaohua; Gore, John C.; Chen, Li min; Landman, Bennett A.; Anderson, Adam W.

2016-03-01

Modern magnetic resonance imaging (MRI) brain atlases are high quality 3-D volumes with specific structures labeled in the volume. Atlases are essential in providing a common space for interpretation of results across studies, for anatomical education, and providing quantitative image-based navigation. Extensive work has been devoted to atlas construction for humans, macaque, and several non-primate species (e.g., rat). One notable gap in the literature is the common squirrel monkey - for which the primary published atlases date from the 1960's. The common squirrel monkey has been used extensively as surrogate for humans in biomedical studies, given its anatomical neuro-system similarities and practical considerations. This work describes the continued development of a multi-modal MRI atlas for the common squirrel monkey, for which a structural imaging space and gray matter parcels have been previously constructed. This study adds white matter tracts to the atlas. The new atlas includes 49 white matter (WM) tracts, defined using diffusion tensor imaging (DTI) in three animals and combines these data to define the anatomical locations of these tracks in a standardized coordinate system compatible with previous development. An anatomist reviewed the resulting tracts and the inter-animal reproducibility (i.e., the Dice index of each WM parcel across animals in common space) was assessed. The Dice indices range from 0.05 to 0.80 due to differences of local registration quality and the variation of WM tract position across individuals. However, the combined WM labels from the 3 animals represent the general locations of WM parcels, adding basic connectivity information to the atlas.

A 3D high resolution ex vivo white matter atlas of the common squirrel monkey (Saimiri sciureus) based on diffusion tensor imaging.

PubMed

Gao, Yurui; Parvathaneni, Prasanna; Schilling, Kurt G; Wang, Feng; Stepniewska, Iwona; Xu, Zhoubing; Choe, Ann S; Ding, Zhaohua; Gore, John C; Chen, Li Min; Landman, Bennett A; Anderson, Adam W

2016-02-27

Modern magnetic resonance imaging (MRI) brain atlases are high quality 3-D volumes with specific structures labeled in the volume. Atlases are essential in providing a common space for interpretation of results across studies, for anatomical education, and providing quantitative image-based navigation. Extensive work has been devoted to atlas construction for humans, macaque, and several non-primate species (e.g., rat). One notable gap in the literature is the common squirrel monkey - for which the primary published atlases date from the 1960's. The common squirrel monkey has been used extensively as surrogate for humans in biomedical studies, given its anatomical neuro-system similarities and practical considerations. This work describes the continued development of a multi-modal MRI atlas for the common squirrel monkey, for which a structural imaging space and gray matter parcels have been previously constructed. This study adds white matter tracts to the atlas. The new atlas includes 49 white matter (WM) tracts, defined using diffusion tensor imaging (DTI) in three animals and combines these data to define the anatomical locations of these tracks in a standardized coordinate system compatible with previous development. An anatomist reviewed the resulting tracts and the inter-animal reproducibility (i.e., the Dice index of each WM parcel across animals in common space) was assessed. The Dice indices range from 0.05 to 0.80 due to differences of local registration quality and the variation of WM tract position across individuals. However, the combined WM labels from the 3 animals represent the general locations of WM parcels, adding basic connectivity information to the atlas.

A 3D high resolution ex vivo white matter atlas of the common squirrel monkey (Saimiri sciureus) based on diffusion tensor imaging

PubMed Central

Gao, Yurui; Parvathaneni, Prasanna; Schilling, Kurt G.; Wang, Feng; Stepniewska, Iwona; Xu, Zhoubing; Choe, Ann S.; Ding, Zhaohua; Gore, John C.; Chen, Li Min; Landman, Bennett A.; Anderson, Adam W.

2016-01-01

Modern magnetic resonance imaging (MRI) brain atlases are high quality 3-D volumes with specific structures labeled in the volume. Atlases are essential in providing a common space for interpretation of results across studies, for anatomical education, and providing quantitative image-based navigation. Extensive work has been devoted to atlas construction for humans, macaque, and several non-primate species (e.g., rat). One notable gap in the literature is the common squirrel monkey – for which the primary published atlases date from the 1960’s. The common squirrel monkey has been used extensively as surrogate for humans in biomedical studies, given its anatomical neuro-system similarities and practical considerations. This work describes the continued development of a multi-modal MRI atlas for the common squirrel monkey, for which a structural imaging space and gray matter parcels have been previously constructed. This study adds white matter tracts to the atlas. The new atlas includes 49 white matter (WM) tracts, defined using diffusion tensor imaging (DTI) in three animals and combines these data to define the anatomical locations of these tracks in a standardized coordinate system compatible with previous development. An anatomist reviewed the resulting tracts and the inter-animal reproducibility (i.e., the Dice index of each WM parcel across animals in common space) was assessed. The Dice indices range from 0.05 to 0.80 due to differences of local registration quality and the variation of WM tract position across individuals. However, the combined WM labels from the 3 animals represent the general locations of WM parcels, adding basic connectivity information to the atlas. PMID:27064328

Three dimensional eye movements of squirrel monkeys following postrotatory tilt

NASA Technical Reports Server (NTRS)

Merfeld, D. M.; Young, L. R.; Paige, G. D.; Tomko, D. L.

1993-01-01

Three-dimensional squirrel monkey eye movements were recorded during and immediately following rotation around an earth-vertical yaw axis (160 degrees/s steady state, 100 degrees/s2 acceleration and deceleration). To study interactions between the horizontal angular vestibulo-ocular reflex (VOR) and head orientation, postrotatory VOR alignment was changed relative to gravity by tilting the head out of the horizontal plane (pitch or roll tilt between 15 degrees and 90 degrees) immediately after cessation of motion. Results showed that in addition to post rotatory horizontal nystagmus, vertical nystagmus followed tilts to the left or right (roll), and torsional nystagmus followed forward or backward (pitch) tilts. When the time course and spatial orientation of eye velocity were considered in three dimensions, the axis of eye rotation always shifted toward alignment with gravity, and the postrotatory horizontal VOR decay was accelerated by the tilts. These phenomena may reflect a neural process that resolves the sensory conflict induced by this postrotatory tilt paradigm.

Endogenous thermoregulatory rhythms of squirrel monkeys in thermoneutrality and cold

NASA Technical Reports Server (NTRS)

Robinson, E. L.; Fuller, C. A.

1999-01-01

Whole body heat production (HP) and heat loss (HL) were examined to determine if the free-running circadian rhythm in body temperature (Tb) results from coordinated changes in HP and HL rhythms in thermoneutrality (27 degrees C) as well as mild cold (17 degrees C). Squirrel monkey metabolism (n = 6) was monitored by both indirect and direct calorimetry, with telemetered measurement of Tb and activity. Feeding was also measured. Rhythms of HP, HL, and conductance were tightly coupled with the circadian Tb rhythm at both ambient temperatures (TA). At 17 degrees C, increased HP compensated for higher HL at all phases of the Tb rhythm, resulting in only minor changes to Tb. Parallel compensatory changes of HP and HL were seen at all rhythm phases at both TA. Similar time courses of Tb, HP, and HL in their respective rhythms and the relative stability of Tb during both active and rest periods suggest action of the circadian timing system on Tb set point.

Self-administration of the anandamide transport inhibitor AM404 by squirrel monkeys.

PubMed

Schindler, Charles W; Scherma, Maria; Redhi, Godfrey H; Vadivel, Subramanian K; Makriyannis, Alexandros; Goldberg, Steven R; Justinova, Zuzana

2016-05-01

N-(4-hydroxyphenyl)-arachidonamide (AM404) is an anandamide transport inhibitor shown to reduce rewarding and relapse-inducing effects of nicotine in several animal models of tobacco dependence. However, the reinforcing/rewarding effects of AM404 are not clear. We investigated whether AM404 maintains self-administration behavior or reinstates extinguished drug seeking in squirrel monkeys. In monkeys with a history of anandamide or cocaine self-administration, we substituted injections of AM404 (1-100 μg/kg/injection). Using a 10-response, fixed-ratio schedule, self-administration behavior was maintained by AM404. Dose-response curves had inverted U shapes, with peak response rates occurring at a dose of 10 μg/kg/injection. In anandamide-experienced monkeys, we also demonstrated self-administration of another anandamide transport inhibitor VDM11. In addition to supporting self-administration, priming injections of AM404 (0.03-0.3 mg/kg) reinstated drug-seeking behavior previously reinforced by cannabinoids (∆(9)-tetrahydrocannabinol (THC) or anandamide) or cocaine. Both AM404 self-administration behavior and reinstatement of drug seeking by AM404 were reduced by treatment with the cannabinoid CB1 receptor antagonist/inverse agonist rimonabant (0.3 mg/kg). Moreover, the reinforcing effects of AM404 were potentiated by the treatment with the fatty acid amide hydrolase (FAAH) inhibitor URB597 (0.3 mg/kg) suggesting a major role of anandamide in these effects. Finally, AM404 (0.3 mg/kg) potentiated the reinforcing effects of anandamide but not those of cocaine. In non-human primates, AM404 effectively reinforced self-administration behavior and induced reinstatement of drug-seeking behavior in abstinent monkeys. These effects appeared to be mediated by cannabinoid CB1 receptors. Therefore, compounds that promote actions of endocannabinoids throughout the brain by inhibiting their membrane transport may have a potential for abuse.

The vestibulo-ocular reflex of the squirrel monkey during eccentric rotation and roll tilt

NASA Technical Reports Server (NTRS)

Merfeld, D. M.; Young, L. R.

1995-01-01

The vestibulo-ocular reflexes (VOR) are determined not only by angular acceleration, but also by the presence of gravity and linear acceleration. This phenomenon was studied by measuring three-dimensional nystagmic eye movements, with implanted search coils, in six male squirrel monkeys during eccentric rotation. Monkeys were rotated in the dark at a constant velocity of 200 degrees/s (centrally or 79 cm off axis) with the axis of rotation always aligned with gravity and the spinal axis of the upright monkeys. The monkey's orientation (facing-motion or back-to-motion) had a dramatic influence on the VOR. These experiments show that: (a) the axis of eye rotation always shifted toward alignment with gravito-inertial force; (b) the peak value of horizontal slow phase eye velocity was greater with the monkey facing-motion than with back-to-motion; and (c) the time constant of horizontal eye movement decay was smaller with the monkey facing-motion than with back-to-motion. All of these findings were statistically significant and consistent across monkeys. In another set of tests, the same monkeys were rapidly tilted about their naso-occipital (roll) axis. Tilted orientations of 45 degrees and 90 degrees were maintained for 1 min. Other than a compensatory angular VOR during the angular rotation, no consistent eye velocity response was observed during or following the tilt for any of the six monkeys. The absence of any eye movement response following tilt weighs against the possibility that translational linear VOR responses are due to simple high-pass filtering of the otolith signals. The VOR response during eccentric rotation was divided into the more familiar angular VOR and linear VOR components. The angular component is known to depend upon semicircular canal dynamics and central influences. The linear component of the response decays rapidly with a mean duration of only 6.6 s, while the axis of eye rotation rapidly aligns (< 10 s) with gravito-inertial force. These

Sleep-wake responses of squirrel monkeys exposed to hyperdynamic environments

NASA Technical Reports Server (NTRS)

Fuller, C. A.

1983-01-01

This study examines the sleep responses of primates to acute 3 Gz environments. To investigate this question, loosely-restrained squirrel monkeys were exposed to 70 minutes of 3 Gz during the day. The animals' behavioral state was polygraphically monitored (EEG, EMG, EOG) along with video and deep body temperature. During the control period, animals exhibited slow wave sleep (SWS) napping behavior. SWS occurred during approximately 20 percent of the control period. Body temperature was maintained at 38.7 C. At 3 Gz, SWS was inhibited for 5 minutes, after which SWS occurred at levels 50 percent lower than in the control period. During the post-centrifugation period, SWS was elevated above the control (50 percent) and hyperdynamic (100 percent) levels. Body temperature was depressed 1.5 C when the animals were at 3 Gz. Thus, hyperdynamic environments are capable of modifying primate sleep behavior, at least as a result of acute exposure. Further, the increased arousal in the hyperdynamic environment is correlated with a lower body temperature. This negative correlation differs from the normal positive correlation of arousal and body temperature.

Behavioral responses of trained squirrel and rhesus monkeys during oculomotor tasks

PubMed Central

Heiney, Shane A.; Blazquez, Pablo M.

2018-01-01

The oculomotor system is the motor system of choice for many neuroscientists studying motor control and learning because of its simplicity, easy control of inputs (e.g., visual stimulation), and precise control and measurement of motor outputs (eye position). This is especially true in primates, which are easily trained to perform oculomotor tasks. Here we provide the first detailed characterization of the oculomotor performance of trained squirrel monkeys, primates used extensively in oculomotor physiology, during saccade and smooth pursuit tasks, and compare it to that of the rhesus macaque. We found that both primates have similar oculomotor behavior but the rhesus shows a larger oculomotor range, better performance for horizontal saccades above 10 degrees, and better horizontal smooth pursuit gain to target velocities above 15 deg/s. These results are important for interspecies comparisons and necessary when selecting the best stimuli to study motor control and motor learning in the oculomotor systems of these primates. PMID:21656216

A detailed analysis of the erythropoietic control system in the human, squirrel, monkey, rat and mouse

NASA Technical Reports Server (NTRS)

Nordheim, A. W.

1985-01-01

The erythropoiesis modeling performed in support of the Body Fluid and Blood Volume Regulation tasks is described. The mathematical formulation of the species independent model, the solutions to the steady state and dynamic versions of the model, and the individual species specific models for the human, squirrel monkey, rat and mouse are outlined. A detailed sensitivity analysis of the species independent model response to parameter changes and how those responses change from species to species is presented. The species to species response to a series of simulated stresses directly related to blood volume regulation during space flight is analyzed.

Comparison of the effects of antipsychotic drugs on the schedule-controlled behavior of squirrel monkeys and pigeons.

PubMed

Barrett, J E

1983-04-01

Lever pressing by squirrel monkeys and key pecking by pigeons were maintained under a multiple 3-min fixed-interval (FI), 30-response fixed-ratio (FR) schedule by the presentation of food. These responses, which differed under the two schedules, but were similar for both species, were used to compare the effects of antipsychotic compounds from different pharmacological classes. Except for differences in potency levels, the effects of intermediate doses of haloperidol and molindone were similar in monkeys and pigeons; these compounds decreased responding under the fixed-interval schedule at doses that did not affect fixed-ratio responding. Similar effects also occurred with chlorpromazine, promazine and thiothixene in pigeons. With monkeys, however, intermediate doses of promazine decreased fixed-ratio responding more than responding maintained under the fixed-interval schedule, while chlorpromazine and thiothixene produced similar effects on responding under both schedules. The effects of novel antipsychotic, clozapine, differed from those of the other agents in both monkeys and pigeons. With both species clozapine increased fixed interval responding at doses that did not affect responding under the fixed-ratio schedule. Doses required to reduce responding at least 50% were approximately 5 to 160 times greater for pigeons than for monkeys for all drugs except clozapine which was equipotent in both species. In monkeys the order of potency was haloperidol greater than molindone = thiothixene greater than chlorpromazine greater than clozapine greater than promazine, whereas in pigeons the order was haloperidol greater than thiothixene greater than clozapine greater than molindone greater than promazine greater than chlorpromazine.

Effect of Prior Influenza Virus Infection on Susceptibility of AKR/J Mice and Squirrel Monkeys to Respiratory Challenge with Legionella pneumophila.

DTIC Science & Technology

1980-07-30

Infection on Susceptibility of AKR/J Mice and Squirrel Monkeys to Respiratory Challenge with Legionella pneumophila RICHARD F. BERENDT U. S. Army Medical...influenza virus and Legionella pneumophila than to either agent alone. b 3 F As knowledge of Legionnaires’ disease has accumulated, the evidence...suggests that many infections occur in individuals with underlying disease. Since Legionella pneumophila appears to spread by the airborne route (5, 6, 8, 9

Predation of a squirrel monkey (Saimiri sciureus) by an Amazon tree boa (Corallus hortulanus): even small boids may be a potential threat to small-bodied platyrrhines.

PubMed

Ribeiro-Júnior, Marco Antônio; Ferrari, Stephen Francis; Lima, Janaina Reis Ferreira; da Silva, Claudia Regina; Lima, Jucivaldo Dias

2016-07-01

Predation has been suggested to play a major role in the evolution of primate ecology, although reports of predation events are very rare. Mammalian carnivores, raptors, and snakes are known predators of Neotropical primates, and most reported attacks by snakes are attributed to Boa constrictor (terrestrial boas). Here, we document the predation of a squirrel monkey (Saimiri sciureus) by an Amazon tree boa (Corallus hortulanus), the first record of the predation of a platyrrhine primate by this boid. The event was recorded during a nocturnal herpetological survey in the Piratuba Lake Biological Reserve, in the north-eastern Brazilian Amazon. The snake was encountered at 20:00 hours on the ground next to a stream, at the final stage of ingesting the monkey. The C. hortulanus specimen was 1620 mm in length (SVL) and weighed 650 g, while the S. sciureus was a young adult female weighing 600 g, 92 % of the body mass of the snake and the largest prey item known to have been ingested by a C. hortulanus. The evidence indicates that the predation event occurred at the end of the afternoon or early evening, and that, while capable of capturing an agile monkey like Saimiri, C. hortulanus may be limited to capturing small platyrrhines such as callitrichines.

Some relations between classically conditioned aggression and conditioned suppression in squirrel monkeys.

PubMed Central

Hake, D F; Campbell, R L

1980-01-01

During three experiments with squirrel monkeys, stimulus and shock pairings were given in the presence of a bite tube. Experiments 1 and 2 used a conditioned-suppression procedure in which bar pressing was reinforced with food. A transparent shield prevented biting of the bar. When the stimulus was paired with shock, bar pressing decreased (conditioned suppression) and tube biting increased during the stimulus (classically conditioned aggression). When the bite tube was removed on alternate sessions in Experiment 2, there was more suppression when the tube was present, thus suggesting that biting competed with bar pressing. However, this simple competing-response interpretation was complicated by the findings of Experiment 3 where, with naive monkeys, bar pressing was never reinforced with food, yet bar pressing was induced during the stimulus and was highest when the bite tube was absent. The fact that stimulus-induced bar pressing developed inciated that bar pressing in conditioned-suppression procedures, suppressed or not, may be maintained by two types of control--the food reinforcer and induced CS control. The higher rate of induced bar pressing during the stimulus with the bite tube absent confounds a simple competing response interpretation of conditioned suppression. It suggests that shock-induced responses during conditioned suppression could be both contributing to and competing with responding maintained by food, with the net effect depending on specific but ill-defined features of the situation. PMID:7190996

Early and late changes in the distal forelimb representation of the supplementary motor area after injury to frontal motor areas in the squirrel monkey.

PubMed

Eisner-Janowicz, Ines; Barbay, Scott; Hoover, Erica; Stowe, Ann M; Frost, Shawn B; Plautz, Erik J; Nudo, Randolph J

2008-09-01

Neuroimaging studies in stroke survivors have suggested that adaptive plasticity occurs following stroke. However, the complex temporal dynamics of neural reorganization after injury make the interpretation of functional imaging studies equivocal. In the present study in adult squirrel monkeys, intracortical microstimulation (ICMS) techniques were used to monitor changes in representational maps of the distal forelimb in the supplementary motor area (SMA) after a unilateral ischemic infarct of primary motor (M1) and premotor distal forelimb representations (DFLs). In each animal, ICMS maps were derived at early (3 wk) and late (13 wk) postinfarct stages. Lesions resulted in severe deficits in motor abilities on a reach and retrieval task. Limited behavioral recovery occurred and plateaued at 3 wk postinfarct. At both early and late postinfarct stages, distal forelimb movements could still be evoked by ICMS in SMA at low current levels. However, the size of the SMA DFL changed after the infarct. In particular, wrist-forearm representations enlarged significantly between early and late stages, attaining a size substantially larger than the preinfarct area. At the late postinfarct stage, the expansion in the SMA DFL area was directly proportional to the absolute size of the lesion. The motor performance scores were positively correlated to the absolute size of the SMA DFL at the late postinfarct stage. Together, these data suggest that, at least in squirrel monkeys, descending output from M1 and dorsal and ventral premotor cortices is not necessary for SMA representations to be maintained and that SMA motor output maps undergo delayed increases in representational area after damage to other motor areas. Finally, the role of SMA in recovery of function after such lesions remains unclear because behavioral recovery appears to precede neurophysiological map changes.

Attenuating Nicotine Reinforcement and Relapse by Enhancing Endogenous Brain Levels of Kynurenic Acid in Rats and Squirrel Monkeys.

PubMed

Secci, Maria E; Auber, Alessia; Panlilio, Leigh V; Redhi, Godfrey H; Thorndike, Eric B; Schindler, Charles W; Schwarcz, Robert; Goldberg, Steven R; Justinova, Zuzana

2017-07-01

The currently available antismoking medications have limited efficacy and often fail to prevent relapse. Thus, there is a pressing need for newer, more effective treatment strategies. Recently, we demonstrated that enhancing endogenous levels of kynurenic acid (KYNA, a neuroinhibitory product of tryptophan metabolism) counteracts the rewarding effects of cannabinoids by acting as a negative allosteric modulator of α7 nicotinic receptors (α7nAChRs). As the effects of KYNA on cannabinoid reward involve nicotinic receptors, in the present study we used rat and squirrel monkey models of reward and relapse to examine the possibility that enhancing KYNA can counteract the effects of nicotine. To assess specificity, we also examined models of cocaine reward and relapse in monkeys. KYNA levels were enhanced by administering the kynurenine 3-monooxygenase (KMO) inhibitor, Ro 61-8048. Treatment with Ro 61-8048 decreased nicotine self-administration in rats and monkeys, but did not affect cocaine self-administration. In rats, Ro 61-8048 reduced the ability of nicotine to induce dopamine release in the nucleus accumbens shell, a brain area believed to underlie nicotine reward. Perhaps most importantly, Ro 61-8048 prevented relapse-like behavior when abstinent rats or monkeys were reexposed to nicotine and/or cues that had previously been associated with nicotine. Ro 61-8048 was also effective in monkey models of cocaine relapse. All of these effects of Ro 61-8048 in monkeys, but not in rats, were reversed by pretreatment with a positive allosteric modulator of α7nAChRs. These findings suggest that KMO inhibition may be a promising new approach for the treatment of nicotine addiction.

Predictive Value of Parkinsonian Primates in Pharmacologic Studies: A Comparison between the Macaque, Marmoset, and Squirrel Monkey.

PubMed

Veyres, Nicolas; Hamadjida, Adjia; Huot, Philippe

2018-05-01

The 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned primate is the gold-standard animal model of Parkinson disease (PD) and has been used to assess the effectiveness of experimental drugs on dyskinesia, parkinsonism, and psychosis. Three species have been used in most studies-the macaque, marmoset, and squirrel monkey-the last much less so than the first two species; however, the predictive value of each species at forecasting clinical efficacy, or lack thereof, is poorly documented. Here, we have reviewed all the published literature detailing pharmacologic studies that assessed the effects of experimental drugs on dyskinesia, parkinsonism, and psychosis in each of these species and have calculated their predictive value of success and failure at the clinical level. We found that, for dyskinesia, the macaque has a positive predictive value of 87.5% and a false-positive rate of 38.1%, whereas the marmoset has a positive predictive value of 76.9% and a false-positive rate of 15.6%. For parkinsonism, the macaque has a positive predictive value of 68.2% and a false-positive rate of 44.4%, whereas the marmoset has a positive predictive value of 86.9% and a false-positive rate of 41.7%. No drug that alleviates psychosis in the clinic has shown efficacy at doing so in the macaque, whereas the marmoset has 100% positive predictive value. The small number of studies conducted in the squirrel monkey precluded us from calculating its predictive efficacy. We hope our results will help in the design of pharmacologic experiments and will facilitate the drug discovery and development process in PD. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

Selective attention to visual compound stimuli in squirrel monkeys (Saimiri sciureus).

PubMed

Ploog, Bertram O

2011-05-01

Five squirrel monkeys served under a simultaneous discrimination paradigm with visual compound stimuli that allowed measurement of excitatory and inhibitory control exerted by individual stimulus components (form and luminance/"color"), which could not be presented in isolation (i.e., form could not be presented without color). After performance exceeded a criterion of 75% correct during training, unreinforced test trials with stimuli comprising recombined training stimulus components were interspersed while the overall reinforcement rate remained constant for training and testing. The training-testing series was then repeated with reversed reinforcement contingencies. The findings were that color acquired greater excitatory control than form under the original condition, that no such difference was found for the reversal condition or for inhibitory control under either condition, and that overall inhibitory control was less pronounced than excitatory control. The remarkably accurate performance throughout suggested that a forced 4-s delay between the stimulus presentation and the opportunity to respond was effective in reducing "impulsive" responding, which has implications for suppressing impulsive responding in children with autism and with attention deficit disorder. Copyright © 2011 Elsevier B.V. All rights reserved.

Role of otolith endorgans in the genesis of vestibular-visual conflict sickness (pitch) in the squirrel monkey (First report)

NASA Technical Reports Server (NTRS)

Igarashi, Makoto; Himi, Tetsuo; Kulecz, Walter B.; Kobayashi, Kazutoyo

1987-01-01

The effects of ablation of the macula utriculi and macula sacculi on vestibular-visual conflict emesis in squirrel monkeys are investigated. An optokinetic drum and a turntable were used for the direction conflict experiment. A significant difference between the preoperative condition and postunilateral and postbilateral utriculo-sacculectomy conditions is observed. It is detected that after unilateral sacculectomy the conflict sickness decreases and no emesis occurs; however, 4.5 months after sacculectomy, the animals regain their conflict sickness. The data reveal that macular afferents are important in the genesis of sensory conflict emesis and two submodalities may be needed to cause conflict sickness onset.

Vestibulo-ocular reflex of the squirrel monkey during eccentric rotation with centripetal acceleration along the naso-occipital axis

NASA Technical Reports Server (NTRS)

Merfeld, D. M.; Paloski, W. H. (Principal Investigator)

1996-01-01

The vestibulo-ocular reflexes (VOR) are determined not only by angular acceleration, but also by the presence of gravity and linear acceleration. This phenomenon was studied by measuring three-dimensional nystagmic eye movements, with implanted search coils, in four male squirrel monkeys. Monkeys were rotated in the dark at 200 degrees/s, centrally or 79 cm off-axis, with the axis of rotation always aligned with gravity and the spinal axis of the upright monkeys. The monkey's position relative to the centripetal acceleration (facing center or back to center) had a dramatic influence on the VOR. These studies show that a torsional response was always elicited that acted to shift the axis of eye rotation toward alignment with gravito-inertial force. On the other hand, a slow phase downward vertical response usually existed, which shifted the axis of eye rotation away from the gravito-inertial force. These findings were consistent across all monkeys. In another set of tests, the same monkeys were rapidly tilted about their interaural (pitch) axis. Tilt orientations of 45 degrees and 90 degrees were maintained for 1 min. Other than a compensatory angular VOR during the rotation, no consistent eye velocity response was ever observed during or following the tilt. The absence of any response following tilt proves that the observed torsional and vertical responses were not a positional nystagmus. Model simulations qualitatively predict all components of these eccentric rotation and tilt responses. These simulations support the conclusion that the VOR during eccentric rotation may consist of two components: a linear VOR and a rotational VOR. The model predicts a slow phase downward, vertical, linear VOR during eccentric rotation even though there was never a change in the force aligned with monkey's spinal (Z) axis. The model also predicts the torsional components of the response that shift the rotation axis of the angular VOR toward alignment with gravito-inertial force.

Vestibulo-ocular reflex of the squirrel monkey during eccentric rotation with centripetal acceleration along the naso-occipital axis.

PubMed

Merfeld, D M

1996-01-01

The vestibulo-ocular reflexes (VOR) are determined not only by angular acceleration, but also by the presence of gravity and linear acceleration. This phenomenon was studied by measuring three-dimensional nystagmic eye movements, with implanted search coils, in four male squirrel monkeys. Monkeys were rotated in the dark at 200 degrees/s, centrally or 79 cm off-axis, with the axis of rotation always aligned with gravity and the spinal axis of the upright monkeys. The monkey's position relative to the centripetal acceleration (facing center or back to center) had a dramatic influence on the VOR. These studies show that a torsional response was always elicited that acted to shift the axis of eye rotation toward alignment with gravito-inertial force. On the other hand, a slow phase downward vertical response usually existed, which shifted the axis of eye rotation away from the gravito-inertial force. These findings were consistent across all monkeys. In another set of tests, the same monkeys were rapidly tilted about their interaural (pitch) axis. Tilt orientations of 45 degrees and 90 degrees were maintained for 1 min. Other than a compensatory angular VOR during the rotation, no consistent eye velocity response was ever observed during or following the tilt. The absence of any response following tilt proves that the observed torsional and vertical responses were not a positional nystagmus. Model simulations qualitatively predict all components of these eccentric rotation and tilt responses. These simulations support the conclusion that the VOR during eccentric rotation may consist of two components: a linear VOR and a rotational VOR. The model predicts a slow phase downward, vertical, linear VOR during eccentric rotation even though there was never a change in the force aligned with monkey's spinal (Z) axis. The model also predicts the torsional components of the response that shift the rotation axis of the angular VOR toward alignment with gravito-inertial force.

Activity budget, diet, and use of space by two groups of squirrel monkeys (Saimiri sciureus) in eastern Amazonia.

PubMed

Pinheiro, Tatyana; Ferrari, Stephen F; Lopes, Maria Aparecida

2013-07-01

Squirrel monkeys (Saimiri spp.) are widely distributed in the Amazon basin. This study describes the ecological and behavioral patterns of two social groups of S. sciureus in forests adjacent to the Tucuruí hydroelectric reservoir in eastern Amazonia, including range size, activity budgets, and composition of the diet. The groups were monitored at Base 4 (group B4) and Germoplasma Island (group GI). Quantitative behavioral data were collected using instantaneous scan sampling to record behavior, substrate use, and height. Home ranges were delimited using a GPS to determine group position after each 50 m of movement. Home ranges were 75.0 ha for group B4 (39 members) and 77.5 ha for group GI (32 members). The use of vertical strata was well defined, with a marked preference for the middle and lower levels of the canopy. The activity budgets of both groups were typical of those of other squirrel monkeys and were dominated by foraging (B4 = 48.7 %; GI = 49.6 %), moving (both groups 28.9 %), and feeding (B4 = 14.6 %; GI = 12.4 %). Resting was rare (B4 = 3.5 %; GI = 2.6 %) and less common than social behavior (B4 = 4.3 %; GI = 6.4 %). The diet of both groups was dominated by plant material (B4 = 70.7 % of feeding records; GI = 71.4 %), which is in contrast with the more insectivorous diets recorded for Saimiri at other sites. Group GI spent more time foraging during the dry season, whereas group B4 spent more time in the rainy season when the consumption of fruit increased (significantly, in the case of group GI). The less insectivorous diet of these groups may be due to a number of factors, including the unique habitat configuration at the site and reduced hydrological stress due to the proximity of the reservoir.

Validation of DTI Tractography-Based Measures of Primary Motor Area Connectivity in the Squirrel Monkey Brain

PubMed Central

Gao, Yurui; Choe, Ann S.; Stepniewska, Iwona; Li, Xia; Avison, Malcolm J.; Anderson, Adam W.

2013-01-01

Diffusion tensor imaging (DTI) tractography provides noninvasive measures of structural cortico-cortical connectivity of the brain. However, the agreement between DTI-tractography-based measures and histological ‘ground truth’ has not been quantified. In this study, we reconstructed the 3D density distribution maps (DDM) of fibers labeled with an anatomical tracer, biotinylated dextran amine (BDA), as well as DTI tractography-derived streamlines connecting the primary motor (M1) cortex to other cortical regions in the squirrel monkey brain. We evaluated the agreement in M1-cortical connectivity between the fibers labeled in the brain tissue and DTI streamlines on a regional and voxel-by-voxel basis. We found that DTI tractography is capable of providing inter-regional connectivity comparable to the neuroanatomical connectivity, but is less reliable measuring voxel-to-voxel variations within regions. PMID:24098365

Number-related discrimination and summation by squirrel monkeys (Saimiri sciureus sciureus and S. boliviensus boliviensus) on the basis of the number of sides of polygons.

PubMed

Terrell, D F; Thomas, R K

1990-09-01

In Experiment 1, with the number of sides or angles of irregular polygons as cues, programmed training, and a 90% correct criterion (36 of 40), 2 squirrel monkeys' (Saimiri sciureus sciureus and S. boliviensus boliviensus) best performances were to discriminate heptagons from octagons, a 3rd's best was hexagons from heptagons, and a 4th's best was pentagons from heptagons. In Experiment 2, on most trials 2 polygons on one or both discriminanda had to be summed to determine which discrimination had the total fewer sides. Only 1 monkey met criterion (27 of 30) on the 2 tasks, 6 vs. 8 and 7 vs. 8 sides, but the other 3 performed better than chance on the 6 vs. 8 task. We conclude that previous studies of animals' discrimination of polygons in terms of complexity were minimally relevant to this work, and counting and subitizing were rejected in favor of a prototype-matching process to explain our monkeys' performances.

Neuronal Control of Mammalian Vocalization, with Special Reference to the Squirrel Monkey

NASA Astrophysics Data System (ADS)

Jürgens, Uwe

Squirrel monkey vocalization can be considered as a suitable model for the study in humans of the neurobiological basis of nonverbal emotional vocal utterances, such as laughing, crying, and groaning. Evaluation of electrical and chemical brain stimulation data, lesioning studies, single-neurone recordings, and neuroanatomical tracing work leads to the following conclusions: The periaqueductal gray and laterally bordering tegmentum of the midbrain represent a crucial area for the production of vocalization. This area collects the various vocalization-triggering stimuli, such as auditory, visual, and somatosensory input from diverse sensory-processing structures, motivation-controlling input from some limbic structures, and volitional impulses from the anterior cingulate cortex. Destruction of this area causes mutism. It is still under dispute whether the periaqueductal region harbors the vocal pattern generator or merely couples vocalization-triggering information to motor-coordinating structures further downward in the brainstem. The periaqueductal region is connected with the phonatory motoneuron pools indirectly via one or several interneurons. The nucleus retroambiguus represents a crucial relay station for the laryngeal and expiratory component of vocalization. The articulatory component reaches the orofacial motoneuron pools via the parvocellular reticular formation. Essential proprioceptive feedback from the larynx and lungs enter the vocal-controlling network via the solitary tract nucleus.

Monkeys, Apes and Other Primates. Young Discovery Library Series.

ERIC Educational Resources Information Center

Lucas, Andre

This book is written for children 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume introduces the primate family, their physiology, and habits. Topics described include: (1) kinds of monkeys, including lemur, chimpanzee, gorilla, squirrel monkey, and marmoset; (2) behaviors when…

The direct connections of the C2 dorsal ganglion in the brain stem of the squirrel monkey: a preliminary investigation *

PubMed Central

Fitz-Ritson, Don E.

1979-01-01

The purpose of this investigation was to observe the possible anatomical connections of C2 dorsal root with brain stem nuclei. Labelled amino acids (leucine, glycine, proline), were injected into the dorsal root of C2 of a squirrel monkey. The animal was allowed to survive for 20 hrs. and after, sections of the spinal cord and brain stem were subjected to autoradiographic methods. Direct connections were observed in Lamina II, VII, VIII of the spinal cord; the hypoglossal nucleus, medial vestibular nucleus, lateral cuneatus nucleus and lateral parvocellular reticular formation. Possible anatomical and physiological correlates are explored in relation to the importance of the upper cervical area and its control mechanisms.

Light masking of circadian rhythms of heat production, heat loss, and body temperature in squirrel monkeys

NASA Technical Reports Server (NTRS)

Robinson, E. L.; Fuller, C. A.

1999-01-01

Whole body heat production (HP) and heat loss (HL) were examined to determine their relative contributions to light masking of the circadian rhythm in body temperature (Tb). Squirrel monkey metabolism (n = 6) was monitored by both indirect and direct calorimetry, with telemetered measurement of body temperature and activity. Feeding was also measured. Responses to an entraining light-dark (LD) cycle (LD 12:12) and a masking LD cycle (LD 2:2) were compared. HP and HL contributed to both the daily rhythm and the masking changes in Tb. All variables showed phase-dependent masking responses. Masking transients at L or D transitions were generally greater during subjective day; however, L masking resulted in sustained elevation of Tb, HP, and HL during subjective night. Parallel, apparently compensatory, changes of HL and HP suggest action by both the circadian timing system and light masking on Tb set point. Furthermore, transient HL increases during subjective night suggest that gain change may supplement set point regulation of Tb.

Differential effects of presynaptic versus postsynaptic adenosine A2A receptor blockade on Δ9-tetrahydrocannabinol (THC) self-administration in squirrel monkeys.

PubMed

Justinová, Zuzana; Redhi, Godfrey H; Goldberg, Steven R; Ferré, Sergi

2014-05-07

Different doses of an adenosine A2A receptor antagonist MSX-3 [3,7-dihydro-8-[(1E)-2-(3-ethoxyphenyl)ethenyl]-7 methyl-3-[3-(phosphooxy)propyl-1-(2 propynil)-1H-purine-2,6-dione] were found previously to either decrease or increase self-administration of cannabinoids delta-9-tetrahydrocannabinol (THC) or anandamide in squirrel monkeys. It was hypothesized that the decrease observed with a relatively low dose of MSX-3 was related to blockade of striatal presynaptic A2A receptors that modulate glutamatergic neurotransmission, whereas the increase observed with a higher dose was related to blockade of postsynaptic A2A receptors localized in striatopallidal neurons. This hypothesis was confirmed in the present study by testing the effects of the preferential presynaptic and postsynaptic A2A receptor antagonists SCH-442416 [2-(2-furanyl)-7-[3-(4-methoxyphenyl)propyl]-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine] and KW-6002 [(E)-1, 3-diethyl-8-(3,4-dimethoxystyryl)-7-methyl-3,7-dihydro-1H-purine-2,6-dione], respectively, in squirrel monkeys trained to intravenously self-administer THC. SCH-442416 produced a significant shift to the right of the THC self-administration dose-response curves, consistent with antagonism of the reinforcing effects of THC. Conversely, KW-6002 produced a significant shift to the left, consistent with potentiation of the reinforcing effects of THC. These results show that selectively blocking presynaptic A2A receptors could provide a new pharmacological approach to the treatment of marijuana dependence and underscore corticostriatal glutamatergic neurotransmission as a possible main mechanism involved in the rewarding effects of THC.

Low-density lipoprotein transport in blood vessel walls of squirrel monkeys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tompkins, R.G.; Yarmush, M.L.; Schnitzer, J.J.

1989-08-01

Transmural accumulations of low-density lipoprotein (LDL) were examined in the blood vessel walls of four squirrel monkeys. Vascular wall concentrations of LDL were measured using quantitative autoradiography after {sup 125}I-labeled LDL circulation for 30 min. Profiles of relative tissue concentration from different sections in the same region were similar to each other, and there was little animal-to-animal variation. Concentrations were highest near the luminal endothelium, lower near the medial-adventitial border, and lowest within the media. Profiles from different regions fell into three groups: (1) aortic samples had steep intimal concentration gradients and near-zero media concentrations; (2) the iliac, femoral, popliteal,more » and common carotid arteries had higher intimal concentrations than group 1 but had similar concentrations deep within the media; and (3) the cerebral and coronary arteries, inferior vena cava, and pulmonary artery had intimal concentrations that were similar to group 2, but the concentrations deep within the media were greater than either groups 1 or 2. Arterial bifurcation profiles from the inner wall and the outer walls were similar to each other and to profiles from the upstream and downstream areas. Out of 280 total sites examined, 15 examples of profiles with substantially increased concentrations near the luminal endothelium were found scattered throughout the cardiovascular system, demonstrating that there are focal regions throughout the cardiovascular system which have greatly increased {sup 125}I-LDL transendothelial permeability.« less

Hair-cell counts and afferent innervation patterns in the cristae ampullares of the squirrel monkey with a comparison to the chinchilla

NASA Technical Reports Server (NTRS)

Fernandez, C.; Lysakowski, A.; Goldberg, J. M.

1995-01-01

1. The numbers of type I and type II hair cells were estimated by dissector techniques applied to semithin, stained sections of the horizontal, superior, and posterior cristae in the squirrel monkey and the chinchilla. 2. The crista in each species was divided into concentrically arranged central, intermediate, and peripheral zones of equal areas. The three zones can be distinguished by the sizes of individual hair cells and calyx endings, by the density of hair cells, and by the relative frequency of calyx endings innervating single or multiple type I hair cells. 3. In the monkey crista, type I hair cells outnumber type II hair cells by a ratio of almost 3:1. The ratio decreases from 4-5:1 in the central and intermediate zones to under 2:1 in the peripheral zone. For the chinchilla, the ratio is near 1:1 for the entire crista and decreases only slightly between the central and peripheral zones. 4. Nerve fibers supplying the cristae in the squirrel monkey were labeled by extracellular injections of horseradish peroxidase (HRP) into the vestibular nerve. Peripheral terminations of individual fibers were reconstructed and related to the zones of the cristae they innervated and to the sizes of their parent axons. Results were similar for the horizontal, superior, and posterior cristae. 5. Axons seldom bifurcate below the neuroepithelium. Most fibers begin branching shortly after crossing the basement membrane. Their terminal arbors are compact, usually extending no more than 50-100 microns from the parent exon. A small number of long intraepithelial fibers enter the intermediate and peripheral zones of the cristae near its base, then run unbranched for long distances through the neuroepithelium to reach the central zone. 6. There are three classes of afferent fibers innervating the monkey crista. Calyx fibers terminate exclusively on type I hair cells, and bouton fibers end only on type II hair cells. Dimorphic fibers provide a mixed innervation, including calyx

The pattern of the arterial supply of the pancreas in anthropoid apes, catarrhine monkeys and platyrrhine monkeys.

PubMed

Shawuti, Alimujiang; Miyaki, Takayoshi; Saito, Toshiyuki; Itoh, Masahiro

2009-11-01

To get the full understanding of the arterial distribution to the pancreas, the analysis of the distribution of the variety of monkey species would be helpful. In this study, we studied the layout of the pancreatic artery in anthropoids (1 gorilla, 3 chimpanzees and 2 white-handed gibbons), in catarrhine monkeys (1 hamadryas baboon, 2 anubid baboons, 10 savannah monkeys) and in platyrrhine monkeys (6 squirrel monkeys). The pancreas of the monkeys was supplied by the arteries originating from the celiac trunk and/or superior mesenteric artery. There were three patterns in the arterial distribution; (1) the celiac artery supplied the major area of the pancreas. (2) the superior mesenteric artery supplied the major area of the pancreas. (3) the celiac artery supplied the whole pancreas. The pattern of the arterial distribution to the monkey pancreas had a wide variety. The result would be helpful for the elucidation of the development of the vascular distribution in the pancreas.

[Monkey-pox, a model of emergent then reemergent disease].

PubMed

Georges, A J; Matton, T; Courbot-Georges, M C

2004-01-01

The recent emergence of monkey pox in the United States of America highlights the problem (known for other infectious agents) of dissemination of pathogens outside their endemic area, and of subsequent global threats of variable gravity according to agents. It is a real emergency since monkey pox had been confined to Africa for several decades, where small epidemics occurred from time to time, monkey pox is a "miniature smallpox" which, in Africa, evolves on an endemic (zoonotic) mode with, as reservoirs, several species of wild rodents (mainly squirrels) and some monkey species. It can be accidentally transmitted to man then develops as epidemics, sometimes leading to death. The virus was imported in 2003 in the United States of America, via Gambia rats and wild squirrels (all African species), and infected prairie dogs (which are now in fashion as pets), then crossed the species barrier to man. In the United States of America, screening campaigns, epidemiological investigations, and subsequent treatments led to a rapid control of the epidemic, which is a model of emergent disease for this country. Therapeutic and preventive measures directly applicable to monkey pox are discussed. They can also be applied against other pox virus infections (including smallpox). The risk of criminal introduction of pox viruses is discussed since it is, more than ever, a real worldwide threat.

Positron emission tomography (PET) imaging of nicotine-induced dopamine release in squirrel monkeys using [18F]Fallypride.

PubMed

Naylor, Jennifer E; Hiranita, Takato; Matazel, Katelin S; Zhang, Xuan; Paule, Merle G; Goodwin, Amy K

2017-10-01

Nicotine, the principal psychoactive tobacco constituent, is thought to produce its reinforcing effects via actions within the mesolimbic dopamine (DA) system. The objective of the current study was to examine the effect of nicotine on DA D 2 /D 3 receptor availability in the nonhuman primate brain with the use of the radioligand [ 18 F]fallypride and positron emission tomography (PET). Ten adult male squirrel monkeys were used in the current study. Each subject underwent two PET scans, one with an injection (IV) of saline and subsequently one with an injection of nicotine (0.032mg/kg). The DA D 2 /D 3 antagonist, [ 18 F]fallypride, was delivered IV at the beginning of each scan, and nicotine or saline was delivered at 45min into the scan. Regions of interest (ROI) were drawn on specific brain regions and these were used to quantify standard uptake values (SUVs). The SUV is defined as the average concentration of radioactivity in the ROI x body weight/injected dose. Using the cerebellum as a reference region, SUV ratios (SUV ROI /SUV cerebellum ) were calculated to compare saline and nicotine effects in each ROI. Two-way repeated ANOVA revealed a significant decrease of SUV ratios in both striatal and extrastriatal regions following an injection of nicotine during the PET scans. Like other drugs of abuse, these results indicate that nicotine administration may produce DA release, as suggested by the decrease in [ 18 F]fallypride signal in striatal regions. These findings from a nonhuman primate model provide further evidence that the mesolimbic DA system is affected by the use of products that contain nicotine. Published by Elsevier B.V.

Cooling and freezing of sperm from captive, free-living and endangered squirrel monkey species.

PubMed

Oliveira, Karol G; Santos, Regiane R; Leão, Danuza L; Brito, Adriel B; Lima, Julianne S; Sampaio, Wlaísa V; Domingues, Sheyla F S

2016-06-01

Germoplasm banking is an important tool for the preservation of genetic material from Neotropical primates in captivity, and from free living species, especially the endangered ones like Saimiri vanzolinii (Black-headed squirrel monkey), a primate with a low incidence area (870 km(2) of floodplains) in the southern part of the Mamirauá Sustainable Development Reserve, Brazil. Therefore, in the present study we aimed to develop a sperm cryopreservation protocol comparing sperm cooling in presence (T1) and absence (T2) of egg yolk, and to test freezing protocols to preserve semen from captive (Saimiri collinsi), and free-living (Saimiri vanzolinii, Saimiri cassiquiarensis and Saimiri macrodon) New World primates. Cooling preserved sperm of S. collinsi in all evaluated microscopic parameters, except for sperm motility. No differences were observed among the treatments, indicating that semen of this species can be cooled without egg yolk. Freezing did not affect sperm quality of S. collinsi, except plasma membrane integrity that was negatively affected. Generally, a good maintenance rate was observed between cooling and thawing of semen for the four species, showing the positive translational application of protocols from S. collinsi to the free-living species. Developed freezing protocol proved to be useful for sperm cryopreservation of S. collinsi and in field conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

Noradrenergic mechanisms in cocaine-induced reinstatement of drug seeking in squirrel monkeys.

PubMed

Platt, Donna M; Rowlett, James K; Spealman, Roger D

2007-08-01

Norepinephrine (NE) uptake and NE receptor mechanisms play important modulating roles in the discriminative stimulus and stimulant effects of cocaine. The present study investigated the role of NE mechanisms in cocaine priming-induced reinstatement of extinguished drug seeking. Squirrel monkeys (Saimiri sciureus) were trained to stability under a second-order fixed interval, fixed ratio schedule of drug self-administration in which operant responding was maintained jointly by i.v. cocaine injections and presentations of a cocaine-paired stimulus. Drug seeking was then extinguished by replacing cocaine with vehicle and eliminating the cocaine-paired stimulus. In test sessions during which the cocaine-paired stimulus was reintroduced but only vehicle was available for self-administration, priming with cocaine, the dopamine transport inhibitor 1-[2-[bis-(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazine (GBR 12909), and the NE transport inhibitors nisoxetine and talsupram induced dose-dependent reinstatement of drug seeking. The maximum effect of the NE transport inhibitors was less than half that of cocaine. Both nisoxetine and talsupram augmented the priming effects of a low but not a high dose of cocaine. The priming effects of nisoxetine were blocked by the alpha1-adrenoceptor antagonist prazosin, the alpha2-adrenoceptor agonist clonidine, and the beta-adrenoceptor antagonist propranolol, but not by the dopamine receptor antagonist flupenthixol. The priming effects of cocaine were antagonized by clonidine and flupenthixol. Neither nisoxetine nor cocaine increased physiological (salivary cortisol) or behavioral (self-directed behaviors) markers of stress. These findings suggest that NE transporter inhibition and alpha2-adrenoceptor mechanisms play a significant role in cocaine-induced reinstatement of drug seeking that is not secondary to activation of brain stress pathways.

Resynchronization of circadian sleep-wake and temperature cycles in the squirrel monkey following phase shifts of the environmental light-dark cycle

NASA Technical Reports Server (NTRS)

Wexler, D. B.; Moore-Ede, M. C.

1986-01-01

Circadian rhythms in physiological and behavioral functions gradually resynchronize after phase shifts in environmental time cues. In order to characterize the rate of circadian resynchronization in a diurnal primate model, the temperature, locomotor activity, and polygraphically determined sleep-wake states were monitored in squirrel monkeys before and after 8-h phase shifts of an environmental light-dark cycle of 12 h light and 12 h dark (LD 12:12). For the temperature rhythm, resynchronization took 4 d after phase delay shift and 5 d after phase advance shift; for the rest-activity cycle, resynchronization times were 3 d and 6 d, respectively. The activity acrophase shifted more rapidly than the temperature acrophase early in the post-delay shift interval, but this internal desynchronization between rhythms disappeared during the course of resynchronization. Further study of the early resynchronization process requires emphasis on identifying evoked effects and measuring circadian pacemaker function.

Variegated Squirrel Bornavirus 1 in Squirrels, Germany and the Netherlands

PubMed Central

Schlottau, Kore; Jenckel, Maria; van den Brand, Judith; Fast, Christine; Herden, Christiane; Höper, Dirk; Homeier-Bachmann, Timo; Thielebein, Jens; Mensing, Niels; Diender, Bert; Hoffmann, Donata; Ulrich, Rainer G.; Mettenleiter, Thomas C.; Koopmans, Marion; Tappe, Dennis; Schmidt-Chanasit, Jonas; Reusken, Chantal B.E.M.; Hoffmann, Bernd

2017-01-01

We screened squirrels in Germany and the Netherlands for the novel zoonotic variegated squirrel bornavirus 1 (VSBV-1). The detection of VSBV-1 in 11 squirrels indicates a considerable risk for transmission to humans handling those animals. Therefore, squirrels in contact with humans should routinely be tested for VSBV-1. PMID:28221112

Measurement of /sup 125/I-low density lipoprotein uptake in selected tissues of the squirrel monkey by quantitative autoradiography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tompkins, R.G.; Schnitzer, J.J.; Yarmush, M.L.

1988-09-01

A recently developed technique of absolute quantitative light microscopic autoradiography of /sup 125/I-labeled proteins in biologic specimens was used to measure /sup 125/I-low density lipoprotein (/sup 125/I-LDL) concentration levels in various tissues of the squirrel monkey after 30 minutes of in vivo LDL circulation. Liver and adrenal cortex exhibited high /sup 125/I-LDL concentrations, presumably because of binding to specific cell surface receptors and/or internalization in vascular beds with high permeability to LDL. High tissue concentrations of LDL were associated with the zona fasciculata and reticularis of the adrenal cortex and the interstitial cells of Leydig in the testis; significantly lowermore » levels of /sup 125/I-LDL were observed in the adrenal medulla, the zona glomerulosa, and germinal centers of the testis. Contrary to previous reports, low /sup 125/I-LDL concentrations were observed throughout the gastrointestinal tract and in lymph nodes. In addition, multiple arterial intramural focal areas of high /sup 125/I-LDL concentrations were identified in arteries supplying the adrenal gland, lymph node, small bowel, and liver.« less

Short poly-glutamine repeat in the androgen receptor in New World monkeys.

PubMed

Hiramatsu, Chihiro; Paukner, Annika; Kuroshima, Hika; Fujita, Kazuo; Suomi, Stephen J; Inoue-Murayama, Miho

2017-12-01

The androgen receptor mediates various physiological and developmental functions and is highly conserved in mammals. Although great intraspecific length polymorphisms in poly glutamine (poly-Q) and poly glycine (poly-G) regions of the androgen receptor in humans, apes and several Old World monkeys have been reported, little is known about the characteristics of these regions in New World monkeys. In this study, we surveyed 17 species of New World monkeys and found length polymorphisms in these regions in three species (common squirrel monkeys, tufted capuchin monkeys and owl monkeys). We found that the poly-Q region in New World monkeys is relatively shorter than that in catarrhines (humans, apes and Old World monkeys). In addition, we observed that codon usage for poly-G region in New World monkeys is unique among primates. These results suggest that the length of polymorphic regions in androgen receptor genes have evolved uniquely in New World monkeys.

Resynchronization of circadian sleep-wake and temperature cycles in the squirrel monkey following phase shifts of the environmental light-dark cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wexler, D.B.; Moore-ede, M.C.

1986-12-01

Circadian rhythms in physiological and behavioral functions gradually resynchronize after phase shifts in environmental time cues. In order to characterize the rate of circadian resynchronization in a diurnal primate model, the temperature, locomotor activity, and polygraphically determined sleep-wake states were monitored in squirrel monkeys before and after 8-h phase shifts of an environmental light-dark cycle of 12 h light and 12 h dark (LD 12:12). For the temperature rhythm, resynchronization took 4 d after phase delay shift and 5 d after phase advance shift; for the rest-activity cycle, resynchronization times were 3 d and 6 d, respectively. The activity acrophasemore » shifted more rapidly than the temperature acrophase early in the post-delay shift interval, but this internal desynchronization between rhythms disappeared during the course of resynchronization. Further study of the early resynchronization process requires emphasis on identifying evoked effects and measuring circadian pacemaker function. 13 references.« less

Vocal Learning via Social Reinforcement by Infant Marmoset Monkeys.

PubMed

Takahashi, Daniel Y; Liao, Diana A; Ghazanfar, Asif A

2017-06-19

For over half a century now, primate vocalizations have been thought to undergo little or no experience-dependent acoustic changes during development [1]. If any changes are apparent, then they are routinely (and quite reasonably) attributed to the passive consequences of growth. Indeed, previous experiments on squirrel monkeys and macaque monkeys showed that social isolation [2, 3], deafness [2], cross-fostering [4] and parental absence [5] have little or no effect on vocal development. Here, we explicitly test in marmoset monkeys-a very vocal and cooperatively breeding species [6]-whether the transformation of immature into mature contact calls by infants is influenced by contingent parental vocal feedback. Using a closed-loop design, we experimentally provided more versus less contingent vocal feedback to twin infant marmoset monkeys over their first 2 months of life, the interval during which their contact calls transform from noisy, immature calls to tonal adult-like "phee" calls [7, 8]. Infants who received more contingent feedback had a faster rate of vocal development, producing mature-sounding contact calls earlier than the other twin. The differential rate of vocal development was not linked to genetics, perinatal experience, or body growth; nor did the amount of contingency influence the overall rate of spontaneous vocal production. Thus, we provide the first experimental evidence for production-related vocal learning during the development of a nonhuman primate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Ablation of Area Postrema on Frequency and Latency of Motion Sickness-Induced Emesis in the Squirrel Monkey

NASA Technical Reports Server (NTRS)

Brizzee, K. R.; Ordy, J. M.; Mehler, W. R.

1980-01-01

Twelve young adult squirrel monkeys of the Bolivian subspecies were subjected to continuous counter-clockwise horizontal rotary motion at 25 rpm, together with a sinusoidal vertical excursion of 6 in. every 2 sec (0.5 Hz). Each animal was exposed to this motion regimen for a period of 60 min once each week for three consecutive weeks. Following the third weekly motion test bilateral ablation of the Area Postrema (AP) was performed in eight of the animals by thermal cautery. Two control animals were sham-operated after the third motion test while two additional controls were given the motion tests as noted above but were not operated. The four controls were considered as a single group for statistical analyses of results of the motion tests. After a recovery period of 30 to 40 days, and at a comparable interval in the non-operated controls, each animal was again tested for motion sensitivity for three consecutive weeks. The brains of all of the animals were then fixed by left ventriculal cardiac perfusion with Bouin's fluid and processed for histological evaluation of the bilateral AP ablation in comparison with the control brains. Five of the AP-ablated animals postoperatively were completely refractory to the motion stimuli, two exhibited a decreased number of emetic responses, and one exhibited the same number of responses before and after the AP lesions. The controls exhibited no significant difference in emetic sensitivity on the second series of three weekly tests than on the first series. The results of this investigation appear to be in agreement with the observations of Wang and Chinn in the dog indicating that the integrity of the AP (CTZ) is essential to the emetic response to motion.

Functional signature of recovering cortex: dissociation of local field potentials and spiking activity in somatosensory cortices of spinal cord injured monkeys.

PubMed

Wang, Zheng; Qi, Hui-Xin; Kaas, Jon H; Roe, Anna W; Chen, Li Min

2013-11-01

After disruption of dorsal column afferents at high cervical spinal levels in adult monkeys, somatosensory cortical neurons recover responsiveness to tactile stimulation of the hand; this reactivation correlates with a recovery of hand use. However, it is not known if all neuronal response properties recover, and whether different cortical areas recover in a similar manner. To address this, we recorded neuronal activity in cortical area 3b and S2 in adult squirrel monkeys weeks after unilateral lesion of the dorsal columns. We found that in response to vibrotactile stimulation, local field potentials remained robust at all frequency ranges. However, neuronal spiking activity failed to follow at high frequencies (≥15 Hz). We suggest that the failure to generate spiking activity at high stimulus frequency reflects a changed balance of inhibition and excitation in both area 3b and S2, and that this mismatch in spiking and local field potential is a signature of an early phase of recovering cortex (

Phylogenomics of species from four genera of New World monkeys by flow sorting and reciprocal chromosome painting

PubMed Central

Dumas, Francesca; Stanyon, Roscoe; Sineo, Luca; Stone, Gary; Bigoni, Francesca

2007-01-01

Background The taxonomic and phylogenetic relationships of New World monkeys (Platyrrhini) are difficult to distinguish on the basis of morphology and because diagnostic fossils are rare. Recently, molecular data have led to a radical revision of the traditional taxonomy and phylogeny of these primates. Here we examine new hypotheses of platyrrhine evolutionary relationships by reciprocal chromosome painting after chromosome flow sorting of species belonging to four genera of platyrrhines included in the Cebidae family: Callithrix argentata (silvered-marmoset), Cebuella pygmaea (pygmy marmoset), Callimico goeldii (Goeldi's marmoset) and Saimiri sciureus (squirrel monkey). This is the first report of reciprocal painting in marmosets. Results The paints made from chromosome flow sorting of the four platyrrhine monkeys provided from 42 to 45 hybridization signals on human metaphases. The reciprocal painting of monkey probes on human chromosomes revealed that 21 breakpoints are common to all four studied species. There are only three additional breakpoints. A breakpoint on human chromosome 13 was found in Callithrix argentata, Cebuella pygmaea and Callimico goeldii, but not in Saimiri sciureus. There are two additional breakpoints on human chromosome 5: one is specific to squirrel monkeys, and the other to Goeldi's marmoset. Conclusion The reciprocal painting results support the molecular genomic assemblage of Cebidae. We demonstrated that the five chromosome associations previously hypothesized to phylogenetically link tamarins and marmosets are homologous and represent derived chromosome rearrangements. Four of these derived homologous associations tightly nest Callimico goeldii with marmosets. One derived association 2/15 may place squirrel monkeys within the Cebidae assemblage. An apparently common breakpoint on chromosome 5q33 found in both Saimiri and Aotus nancymae could be evidence of a phylogenetic link between these species. Comparison with previous reports

Phylogenetic analysis of HERV-K LTR-like elements in primates: presence in some new world monkeys and evidence of recent parallel evolution in these species and in homo sapiens.

PubMed

Kim, H S; Wadekar, R V; Takenaka, O; Hyun, B H; Crow, T J

1999-01-01

Solitary long terminal repeats (LTRs) of the human endogenous retroviruses K family (HERV-K) have been found to be coexpressed with sequences of closely located genes. We identified forty-three HERV-K LTR-like elements in primates (African great apes, two Old World monkeys, and two New World monkeys) and analyzed them along with human-specific HERV-K LTRs. We report detection of HERV-K LTR-like elements from New World monkeys, as represented by the squirrel monkey and the night monkey, for the first time. Analysis revealed a high degree of sequence homology with human-specific HERV-K LTRs. A phylogenetic tree obtained by the neighbor-joining method revealed that five sequence (SMS-1, 2, 5, 6, 7) from the squirrel monkey and three sequences (NM6-4, 5, 9) from the night monkey are more closely related to human-specific HERV-K LTRs than they are to those of apes (the chimpanzee and gorilla) and Old World monkeys (the African green monkey and rhesus monkey). The findings are consistent with the concept the HERV-K LTR-like elements have proliferated independently and recently in the genome of primates, and that such proliferation has been more recent in Homo sapiens and in these representatives of New World monkeys than in some Old World monkeys.

Differential effects of the metabotropic glutamate 2/3 receptor agonist LY379268 on nicotine versus cocaine self-administration and relapse in squirrel monkeys.

PubMed

Justinova, Zuzana; Le Foll, Bernard; Redhi, Godfrey H; Markou, Athina; Goldberg, Steven R

2016-05-01

Group II metabotropic glutamate receptors (mGluR2 and mGluR3) have been suggested to play an important role in mediation of drug-reinforced behaviors, as well as in the mechanisms underlying relapse in abstinent subjects. The prototypical mGluR2/3 agonist, LY379268, has been shown to attenuate nicotine reinforcement and cue-induced reinstatement of drug seeking in rats, as well as reinstatement induced by drug-associated stimuli and contexts across different drugs of abuse (i.e., cocaine, heroin, and methamphetamine). However, in primates, LY379268 has been shown to produce conflicting results on abuse-related effects of cocaine, and there are no data available for nicotine. To explore the therapeutic potential of mGluR2/3 agonists, we compared the effects of LY379268 (0.03-1.0 mg/kg) on nicotine, cocaine, and food self-administration under a fixed-ratio (FR10) schedule in three separate groups of squirrel monkeys. Moreover, we studied the effects of LY379268 on nicotine/cocaine priming-induced and cue-induced reinstatement of drug-seeking behavior in nicotine- and cocaine-experienced groups of animals. LY379268 blocked nicotine, but not cocaine, self-administration in monkeys. There was a partial overlap between doses that affected nicotine and food self-administration. In abstinent monkeys, LY379268 dose-dependently blocked nicotine, but not cocaine, priming-induced reinstatement of drug seeking. In both cocaine-experienced and nicotine-experienced groups of animals, LY379268 potently reduced cue-induced reinstatement of drug-seeking behavior. The present findings provide strong support for the potential utility of mGlu2/3 receptor agonists for the treatment of nicotine dependence and suggest their utility for prevention of relapse induced by environmental cues associated with drug taking.

Effects of kappa opioid agonists alone and in combination with cocaine on heart rate and blood pressure in conscious squirrel monkeys.

PubMed

Schindler, Charles W; Graczyk, Zofi; Gilman, Joanne P; Negus, S Stevens; Bergman, Jack; Mello, Nancy K; Goldberg, Steven R

2007-12-08

As kappa agonists have been proposed as treatments for cocaine abuse, the cardiovascular effects of the kappa opioid receptor agonists ethylketocyclazocine (EKC) and enadoline were investigated in conscious squirrel monkeys. Both EKC and enadoline increased heart rate with little effect on blood pressure. This effect appeared to be specific for kappa receptors as the mu opioid agonist morphine did not mimic the effects of the kappa agonists. The opioid antagonist naltrexone, at a dose of 1.0 mg/kg, blocked the effect of EKC. An action at both central and peripheral receptors may be responsible for the heart rate increase following kappa agonist treatment. The ganglionic blocker chlorisondamine partially antagonized the effect of EKC on heart rate, suggesting central involvement, while the peripherally-acting agonist ICI 204,448 ((+/-)-1-[2,3- (Dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol hydrochloride) also increased heart rate, supporting a peripheral site of action. When given in combination with cocaine, EKC produced effects that were sub-additive, suggesting that the kappa agonists may be used safely as cocaine abuse treatments.

Modification of pharmacokinetic and abuse-related effects of cocaine by human-derived cocaine hydrolase in monkeys

PubMed Central

Schindler, Charles W.; Justinova, Zuzana; Lafleur, David; Woods, Doug; Roschke, Viktor; Hallak, Hussein; Sklair-Tavron, Liora; Redhi, Godfrey H.; Yasar, Sevil; Bergman, Jack; Goldberg, Steven R.

2011-01-01

Although substantial research effort has focused on developing pharmacological treatments for cocaine abuse, no effective medications have been developed. Recent studies show that enzymes that metabolize cocaine in the periphery, forestalling its entry into the brain, can prevent cocaine toxicity and its behavioral effects in rodents. Here we report on effects of one such enzyme (Albu-CocH) on the pharmacokinetic and behavioral effects of cocaine in squirrel monkeys. Albu-CocH was developed from successive mutations of human butyrylcholinesterase (BChE) and has 1000-fold greater catalytic activity against cocaine than naturally occurring BChE. Pharmacokinetic studies showed that Albu-CocH (5 mg/kg) had a half-life of 56.6 hours in squirrel monkeys. In these studies, plasma levels of cocaine following i.v. 1 mg/kg cocaine were reduced two hours after administration of Albu-CocH, whereas plasma levels of the cocaine metabolite ecgonine methyl ester were increased. These effects were still evident 72 hrs following Albu-CocH administration. In behavioral experiments in monkeys, pretreatment with 5 mg/kg Albu-CocH dramatically decreased self-administration of a reinforcing dose of i.v. cocaine (30 μg/kg/injection) for over 24 hours. Pretreatment with 5 mg/kg Albu-CocH also attenuated the reinstatement of extinguished cocaine self-administration by an i.v. priming injection of cocaine (0.1 or 0.3 mg/kg) and, in separate studies, attenuated the discriminative stimulus effects of cocaine. The ability of Albu-CocH to attenuate the abuse-related effects of cocaine in squirrel monkeys indicates that further investigation of BChE mutants as potential treatment for cocaine abuse and toxicity is warranted. PMID:22264200

Populations and habitat relationships of Piute ground squirrels in southwest Idaho

USGS Publications Warehouse

Steenhof, Karen; Yensen, Eric; Kochert, Michael N.; Gage, K.

2006-01-01

Piute ground squirrels (Spermophilus mollis idahoensis) are normally above ground from late January until late June or early July in the Snake River Birds of Prey National Conservation Area in southwestern Idaho. In 2002 they were rarely seen above ground after early May. Because of the ecological importance of ground squirrels for nesting raptors and other species, we sought to determine the reasons for their early disappearance. We sampled 12 sites from January 2003 through March 2003 to determine if a population crash had occurred in 2002. Tests indicated that Piute ground squirrels had not been exposed to plague within the past year. The presence of yearlings in the population indicated that squirrels reproduced in 2002 and that at least some yearlings survived the winter. Both yearling and adult squirrels appeared to be reproducing at or above normal rates in 2003. The most plausible explanation for the early disappearance of Piute ground squirrels in 2002 is that squirrels entered seasonal torpor early in response to a late spring drought. In addition, the breeding chronology of squirrels may have shifted during the past 2 decades in response to climate change and/or habitat alteration. Shrub habitats provide a more favorable and stable environment for squirrels than grass habitats. Squirrel abundance was higher on live-trapping grids with sagebrush than on grids dominated by grass, and squirrel masses were higher at sites dominated by shrubs and Sandberg bluegrass (Poa secunda). Densities in big sagebrush (Artemisia tridentata) were within the ranges reported for earlier years, but densities in grass were lower than previously reported. Low densities at grassland sites in 2003 support other findings that drought affects squirrels in altered grass communities more than those in native shrub habitats. Long-term shifts in ground squirrel breeding chronology may have implications for raptors that depend on them for food.

No evidence for neo-oogenesis may link to ovarian senescence in adult monkey.

PubMed

Yuan, Jihong; Zhang, Dongdong; Wang, Lei; Liu, Mengyuan; Mao, Jian; Yin, Yu; Ye, Xiaoying; Liu, Na; Han, Jihong; Gao, Yingdai; Cheng, Tao; Keefe, David L; Liu, Lin

2013-11-01

Female germline or oogonial stem cells transiently residing in fetal ovaries are analogous to the spermatogonial stem cells or germline stem cells (GSCs) in adult testes where GSCs and meiosis continuously renew. Oocytes can be generated in vitro from embryonic stem cells and induced pluripotent stem cells, but the existence of GSCs and neo-oogenesis in adult mammalian ovaries is less clear. Preliminary findings of GSCs and neo-oogenesis in mice and humans have not been consistently reproducible. Monkeys provide the most relevant model of human ovarian biology. We searched for GSCs and neo-meiosis in ovaries of adult monkeys at various ages, and compared them with GSCs from adult monkey testis, which are characterized by cytoplasmic staining for the germ cell marker DAZL and nuclear expression of the proliferative markers PCNA and KI67, and pluripotency-associated genes LIN28 and SOX2, and lack of nuclear LAMIN A, a marker for cell differentiation. Early meiocytes undergo homologous pairing at prophase I distinguished by synaptonemal complex lateral filaments with telomere perinuclear distribution. By exhaustive searching using comprehensive experimental approaches, we show that proliferative GSCs and neo-meiocytes by these specific criteria were undetectable in adult mouse and monkey ovaries. However, we found proliferative nongermline somatic stem cells that do not express LAMIN A and germ cell markers in the adult ovaries, notably in the cortex and granulosa cells of growing follicles. These data support the paradigm that adult ovaries do not undergo germ cell renewal, which may contribute significantly to ovarian senescence that occurs with age. Copyright © 2013 AlphaMed Press.

Modification of pharmacokinetic and abuse-related effects of cocaine by human-derived cocaine hydrolase in monkeys.

PubMed

Schindler, Charles W; Justinova, Zuzana; Lafleur, David; Woods, Doug; Roschke, Viktor; Hallak, Hussein; Sklair-Tavron, Liora; Redhi, Godfrey H; Yasar, Sevil; Bergman, Jack; Goldberg, Steven R

2013-01-01

Although substantial research effort has focused on developing pharmacological treatments for cocaine abuse, no effective medications have been developed. Recent studies show that enzymes that metabolize cocaine in the periphery, forestalling its entry into the brain, can prevent cocaine toxicity and its behavioral effects in rodents. Here we report on effects of one such enzyme (Albu-CocH) on the pharmacokinetic and behavioral effects of cocaine in squirrel monkeys. Albu-CocH was developed from successive mutations of human butyrylcholinesterase (BChE) and has 1000-fold greater catalytic activity against cocaine than naturally occurring BChE. Pharmacokinetic studies showed that Albu-CocH (5 mg/kg) had a half-life of 56.6 hours in squirrel monkeys. In these studies, plasma levels of cocaine following i.v. 1 mg/kg cocaine were reduced 2 hours after administration of Albu-CocH, whereas plasma levels of the cocaine metabolite ecgonine methyl ester were increased. These effects were still evident 72 hours following Albu-CocH administration. In behavioral experiments in monkeys, pre-treatment with 5 mg/kg Albu-CocH dramatically decreased self-administration of a reinforcing dose of i.v. cocaine (30 µg/kg/injection) for over 24 hours. Pre-treatment with 5 mg/kg Albu-CocH also attenuated the reinstatement of extinguished cocaine self-administration by an i.v. priming injection of cocaine (0.1 or 0.3 mg/kg) and, in separate studies, attenuated the discriminative-stimulus effects of cocaine. The ability of Albu-CocH to attenuate the abuse-related effects of cocaine in squirrel monkeys indicates that further investigation of BChE mutants as potential treatment for cocaine abuse and toxicity is warranted. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

Nucleolar changes in response to dietary protein malnutrition in the neurons of the motor cerebral cortex and cerebellum of squirrel moneky Saimiri sciureus.

PubMed

Manocha, S L; Sharma, S P

1978-01-01

Nucleolo-cytoplasmic relationships have been studied in healthy squirrel monkeys and those subjected to a known degree of protein malnutrition. In the latter group, thirty-two pregnant animals starting from 35 days of gestation and 24 young adult animals were given a diet containing 7.5% and 2.0% protein content, respectively, compared to a diet with 25% protein for the controls. The motor cortex and the cerebellum removed from neonates as well as young adult animals sacrificed after 9, 11, 13 and 15 weeks of feeding schedules were investigated. Four animals after 15 weeks of dietary protein deprivation were rehabilitated with a balanced diet over a year's period. Formaldehyde-fixed as well as fresh frozen tissues were used for the histological study and to employ histochemical techniques for the demonstration of lipids, carbohydrates, nucleic acids and enzymes of various metabolic cycles. As a result of protein malnutrition, the nucleolus in a majority of the neurons from the motor cortex and the Purkinje cells of the cerebellum undergoes a series of morphological and cytochemical transformations in response to cytoplasmic changes related to impaired protein metabolism. The greater the level of protein deprivation, the greater is the degree of cytoplasmic chromatolysis and more pronounced are the nucleolar transformation in terms of enlarged size, secretory activity and transfer of nucleolar material in the cytoplasm. The nucleolar buds located close to the periphery of the nuclear membrane and the nucleolar material in the cytoplasm show identical cytochemical nature except for the presence of DNA in the former. It appears that during migration through the nuclear membrane the nucleolar material loses its DNA component and only aggregates of ribosomes and protein pass into cytoplasm, which aid in the synthesis of specific proteins lost as a result of catabolic processes initiated by protein malnutrition. Most of the observed changes in the adult squirrel monkeys

Modeling the vestibulo-ocular reflex of the squirrel monkey during eccentric rotation and roll tilt

NASA Technical Reports Server (NTRS)

Merfeld, D. M.; Paloski, W. H. (Principal Investigator)

1995-01-01

Model simulations of the squirrel monkey vestibulo-ocular reflex (VOR) are presented for two motion paradigms: constant velocity eccentric rotation and roll tilt about a naso-occipital axis. The model represents the implementation of three hypotheses: the "internal model" hypothesis, the "gravito-inertial force (GIF) resolution" hypothesis, and the "compensatory VOR" hypothesis. The internal model hypothesis is based on the idea that the nervous system knows the dynamics of the sensory systems and implements this knowledge as an internal dynamic model. The GIF resolution hypothesis is based on the idea that the nervous system knows that gravity minus linear acceleration equals GIF and implements this knowledge by resolving the otolith measurement of GIF into central estimates of gravity and linear acceleration, such that the central estimate of gravity minus the central estimate of acceleration equals the otolith measurement of GIF. The compensatory VOR hypothesis is based on the idea that the VOR compensates for the central estimates of angular velocity and linear velocity, which sum in a near-linear manner. During constant velocity eccentric rotation, the model correctly predicts that: (1) the peak horizontal response is greater while "facing-motion" than with "back-to-motion"; (2) the axis of eye rotation shifts toward alignment with GIF; and (3) a continuous vertical response, slow phase downward, exists prior to deceleration. The model also correctly predicts that a torsional response during the roll rotation is the only velocity response observed during roll rotations about a naso-occipital axis. The success of this model in predicting the observed experimental responses suggests that the model captures the essence of the complex sensory interactions engendered by eccentric rotation and roll tilt.

Effects of prenatal /sup 60/Co irradiation on postnatal neural, learning, and hormonal development of the squirrel monkey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ordy, J.M.; Brizzee, K.R.; Dunlap, W.P.

1982-02-01

The goals of this study were to examine the effects of 0, 50, and 100 rad of /sup 60/Co administered prenatally on postnatal development of neuromuscular coordination, visual discrimination learning, spontaneous light-dark stabilimeter activity, plasma cortisol, and somatometric growth rates of diurnal squirrel monkeys from birth to 90 days. In terms of accuracy, completeness, and time required for performance of reflexes and neuromuscular coordination, the performance of 50- and 100-rad offspring was less accurate and poorly coordinated and required more time for completion to that of controls. In visual orientation, discrimination, and reversal learning, the percentage correct responses of themore » 50- and 100-rad offspring were significantly lower than those of controls. Spontaneous light-dark stabilimeter activity of 50- and 100-rad offspring was significantly higher in the dark session than that of controls. Plasma cortisol was significantly higher in 100-rad infants than in controls. Comparisons of somatometric growth rates indicated that postnatal head circumference, crown-rump length, and to a lesser extent body weight increased at significantly slower rates in 50- and 100-rad offspring. These findings should provide essential information for formulating and carrying out multivariate behavioral, biochemical, and morphometric assessments of low-dose effects on the brain of primate offspring within demonstrable dose-response curves.« less

Pharmacokinetics of bisphenol A in neonatal and adult rhesus monkeys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doerge, Daniel R., E-mail: daniel.doerge@fda.hhs.go; Twaddle, Nathan C.; Woodling, Kellie A.

Bisphenol A (BPA) is a high-production volume industrial chemical used in the manufacture of polycarbonate plastic products and epoxy resin-based food can liners. The presence of BPA in urine of > 90% of Americans aged 6-60 is controversial because of the potential for endocrine disruption, particularly during perinatal development, as suggested by in vitro, experimental animal, and epidemiological studies. The current study used LC/MS/MS to measure serum pharmacokinetics of aglycone (active) and conjugated (inactive) BPA in adult and neonatal rhesus monkeys by oral (PND 5, 35, 70) and intravenous injection (PND 77) routes using d6-BPA to avoid sample contamination. Themore » concentration-time profiles observed in adult monkeys following oral administration of 100 {mu}g/kg bw were remarkably similar to those previously reported in human volunteers given a similar dose; moreover, minimal pharmacokinetic differences were observed between neonatal and adult monkeys for the receptor-active aglycone form of BPA. Circulating concentrations of BPA aglycone were quite low following oral administration (< 1% of total), which reflects the redundancy of active UDP-glucuronosyl transferase isoforms in both gut and liver. No age-related changes were seen in internal exposure metrics for aglycone BPA in monkeys, a result clearly different from developing rats where significant inverse age-related changes, based on immaturity of Phase II metabolism and renal excretion, were recently reported. These observations imply that any toxicological effect observed in rats from early postnatal exposures to BPA could over-predict those possible in primates of the same age, based on significantly higher internal exposures and overall immaturity at birth.« less

Immediate or lagged responses of a red squirrel population to pulsed resources.

PubMed

Selonen, Vesa; Varjonen, Rauno; Korpimäki, Erkki

2015-02-01

According to producer-consumer models, consumers should follow pulsed resources with a time lag. This view has been challenged by studies demonstrating that individuals may anticipate future resource pulses by increasing reproduction just before the pulse. We studied population fluctuations and reproduction in European red squirrels, Sciurus vulgaris, in relation to seed masting of the main food resource (the Norway spruce) in boreal coniferous forests between 1979 and 2013. Red squirrels are pre-dispersal seed predators, and previous studies have shown that they can anticipate the coming seed mast. We did not find any indication that anticipation of masting (year t ) increased red squirrel reproduction in the preceding spring to early summer. Instead, the reproductive output of the squirrels was highest in the spring following the mast, indicating that the population had to be at its largest size in the autumn after the mast (year(t+1)), when lots of subadults were around. However, we surmised, based on snow tracks and squirrel nest data, that the population crashed during the following winter (year(t+1)). These data reflected the adult population during winter, which peaked at the same time as the resource pulse. We can therefore conclude that the time lag between the resource pulse and the attainment of the peak number of squirrels was less than one year, and that the resource crash affected more juveniles and subadults than adults. The population increase overlapped with the occurrence of masting, but there was also a lagged response, supporting the classical view of producer-consumer models.

Perfect polydactylism in hind feet of a gray squirrel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dunaway, P.B.

1969-01-01

An adult gray squirrel from an isolated natural population had seven toes and nine plantar tubercles on each hind foot. The extra digits were articulated with supernumerary cuneiforms and appeared to have been functional. Polydactylism in wild adult rodents is probably a rare anomaly. 6 references, 2 figures.

Effects of drought and prolonged winter on Townsend's ground squirrel demography in shrubsteppe habitats

USGS Publications Warehouse

Van Horne, Beatrice; Olson, Gail S.; Schooley, Robert L.; Corn, Janelle G.; Burnham, Kenneth P.

1997-01-01

During a mark–recapture study of Townsend's ground squirrels (Spermophilus townsendii) on 20 sites in the Snake River Birds of Prey National Conservation Area, Idaho, in 1991 through 1994, 4407 animals were marked in 17639 capture events. This study of differences in population dynamics of Townsend's ground squirrels among habitats spanned a drought near the extreme of the 130-yr record, followed by prolonged winter conditions.Townsend's ground squirrels have a short active season (≈4 mo) in which to reproduce and store fat for overwintering. Their food consists largely of succulent grasses and forbs in this dry shrubsteppe and grassland habitat. The drought in the latter half of the 1992 active season produced early drying of Sandberg's bluegrass (Poa secunda) and was associated with low adult and juvenile body masses prior to immergence into estivation/hibernation. The following prolonged winter was associated with late emergence of females in 1993. Early-season body masses of adults were low in 1993 relative to 1992, whereas percentage of body fat in males was relatively high. These weather patterns in spring 1992 and winter 1993 also resulted in reduced adult persistence through the ≈7-mo inactive period, especially for adult females, and near-zero persistence of >1200 juveniles. Consequently, densities of Townsend's ground squirrels across the 20 livetrap sites declined.The demographic effects of drought and prolonged winter lasted at least through the subsequent breeding season. Adult females that survived these weather extremes produced fewer emergent young per female than did adult females prior to the event. Prior to the drought/prolonged winter, yearling female body masses were higher than, or indistinguishable from, those of adults. Females produced in 1993 had lower body masses as yearlings than did adult females.Demographic response to the drought and prolonged winter varied with habitat; ground squirrels in sagebrush habitat showed less decline

Adrenergic responsiveness is reduced, while baseline cardiac function is preserved in old adult conscious monkeys

NASA Technical Reports Server (NTRS)

Sato, N.; Kiuchi, K.; Shen, Y. T.; Vatner, S. F.; Vatner, D. E.

1995-01-01

To examine the physiological deficit to adrenergic stimulation with aging, five younger adult (3 +/- 1 yr old) and nine older adult (17 +/- 1 yr old) healthy monkeys were studied after instrumentation with a left ventricular (LV) pressure gauge, aortic and left atrial catheters, and aortic flow probes to measure cardiac output directly. There were no significant changes in baseline hemodynamics in conscious older monkeys. For example, an index of contractility, the first derivative of LV pressure (LV dP/dt) was similar (3,191 +/- 240, young vs. 3,225 +/- 71 mmHg/s, old) as well as in isovolumic relaxation, tau (24.3 +/- 1.7 ms, young vs. 23.0 +/- 1.0 ms, old) was similar. However, inotropic, lusitropic, and chronotropic responses to isoproterenol (Iso; 0.1 micrograms/kg), norepinephrine (NE; 0.4 micrograms/kg), and forskolin (For; 75 nmol/kg) were significantly (P < 0.05) depressed in older monkeys. For example. Iso increased LV dP/dt by by 146 +/- 14% in younger monkeys and by only 70 +/- 5% in older monkeys. Iso also reduced tau more in younger monkeys (-28 +/- 7%) compared with older monkeys (-13 +/- 3%). Furthermore, peripheral vascular responsiveness to Iso, NE, For, and phenylephrine (PE; 5 micrograms/kg) was significantly (P < 0.05) reduced in older monkeys. For example, phenylephrine (5 micrograms/kg) increased total peripheral resistence by 69 +/- 4% in younger monkeys and by only 45 +/- 3% in older monkeys. Thus in older monkeys without associated cardiovascular disease, baseline hemodynamics are preserved, but adrenergic receptor responsiveness is reduced systemically, not just in the heart.

Spatiotemporal trajectories of reactivation of somatosensory cortex by direct and secondary pathways after dorsal column lesions in squirrel monkeys

PubMed Central

Qi, Hui-Xin; Wang, Feng; Liao, Chia-Chi; Friedman, Robert M.; Tang, Chaohui; Kaas, Jon H.; Avison, Malcolm J.

2016-01-01

After lesions of the somatosensory dorsal column (DC) pathway, the cortical hand representation can become unresponsive to tactile stimuli, but considerable responsiveness returns over weeks of post-lesion recovery. The reactivation suggests that preserved subthreshold sensory inputs become potentiated and axon sprouting occurs over time to mediate recovery. Here, we studied the recovery process in 3 squirrel monkeys, using high-resolution fMRI CBV-fMRI mapping of contralateral somatosensory cortex responsiveness to stimulation of distal finger pads with low and high level electrocutaneous stimulation (ES) before and 2, 4, and 6 weeks after a high cervical level contralateral DC lesion. Both low and high intensity ES of digits revealed the expected somatotopy of the area 3b hand representation in pre-lesion monkeys, while in areas 1 and 3a, high intensity stimulation was more effective in activating somatotopic patterns. Six weeks post-lesion, and irrespective of the severity of loss of direct DC inputs (98%, 79%, 40%), somatosensory cortical area 3b of all three animals showed near complete recovery in terms of somatotopy and responsiveness to low and high intensity ES. However there was significant variability in the patterns and amplitudes of reactivation of individual digit territories within and between animals, reflecting differences in the degree of permanent and/or transient silencing of primary DC and secondary inputs 2 weeks post-lesion, and their spatio-temporal trajectories of recovery between 2 and 6 weeks. Similar variations in the silencing and recovery of somatotopy and responsiveness to high intensity ES in areas 3a and 1 are consistent with inter-individual differences in collateral damage to and recovery of secondary (e.g. spinothalamic) pathways. Thus, cortical deactivation and subsequent reactivation depends not only on the degree of DC lesion, but also on the severity and duration of loss of secondary as well as primary inputs revealed by low

Differential adaptation of the linear and nonlinear components of the horizontal vestibuloocular reflex in squirrel monkeys

NASA Technical Reports Server (NTRS)

Clendaniel, Richard A.; Lasker, David M.; Minor, Lloyd B.; Shelhamer, M. J. (Principal Investigator)

2002-01-01

Previous work in squirrel monkeys has demonstrated the presence of linear and nonlinear components to the horizontal vestibuloocular reflex (VOR) evoked by high-acceleration rotations. The nonlinear component is seen as a rise in gain with increasing velocity of rotation at frequencies more than 2 Hz (a velocity-dependent gain enhancement). We have shown that there are greater changes in the nonlinear than linear component of the response after spectacle-induced adaptation. The present study was conducted to determine if the two components of the response share a common adaptive process. The gain of the VOR, in the dark, to sinusoidal stimuli at 4 Hz (peak velocities: 20-150 degrees /s) and 10 Hz (peak velocities: 20 and 100 degrees /s) was measured pre- and postadaptation. Adaptation was induced over 4 h with x0.45 minimizing spectacles. Sum-of-sines stimuli were used to induce adaptation, and the parameters of the stimuli were adjusted to invoke only the linear or both linear and nonlinear components of the response. Preadaptation, there was a velocity-dependent gain enhancement at 4 and 10 Hz. In postadaptation with the paradigms that only recruited the linear component, there was a decrease in gain and a persistent velocity-dependent gain enhancement (indicating adaptation of only the linear component). After adaptation with the paradigm designed to recruit both the linear and nonlinear components, there was a decrease in gain and no velocity-dependent gain enhancement (indicating adaptation of both components). There were comparable changes in the response to steps of acceleration. We interpret these results to indicate that separate processes drive the adaptation of the linear and nonlinear components of the response.

Ultrasonic Vocalizations Emitted by Flying Squirrels

PubMed Central

Murrant, Meghan N.; Bowman, Jeff; Garroway, Colin J.; Prinzen, Brian; Mayberry, Heather; Faure, Paul A.

2013-01-01

Anecdotal reports of ultrasound use by flying squirrels have existed for decades, yet there has been little detailed analysis of their vocalizations. Here we demonstrate that two species of flying squirrel emit ultrasonic vocalizations. We recorded vocalizations from northern (Glaucomys sabrinus) and southern (G. volans) flying squirrels calling in both the laboratory and at a field site in central Ontario, Canada. We demonstrate that flying squirrels produce ultrasonic emissions through recorded bursts of broadband noise and time-frequency structured frequency modulated (FM) vocalizations, some of which were purely ultrasonic. Squirrels emitted three types of ultrasonic calls in laboratory recordings and one type in the field. The variety of signals that were recorded suggest that flying squirrels may use ultrasonic vocalizations to transfer information. Thus, vocalizations may be an important, although still poorly understood, aspect of flying squirrel social biology. PMID:24009728

Stress in biological invasions: Introduced invasive grey squirrels increase physiological stress in native Eurasian red squirrels.

PubMed

Santicchia, Francesca; Dantzer, Ben; van Kesteren, Freya; Palme, Rupert; Martinoli, Adriano; Ferrari, Nicola; Wauters, Lucas Armand

2018-05-23

Invasive alien species can cause extinction of native species through processes including predation, interspecific competition for resources or disease-mediated competition. Increases in stress hormones in vertebrates may be associated with these processes and contribute to the decline in survival or reproduction of the native species. Eurasian red squirrels (Sciurus vulgaris) have gone extinct across much of the British Isles and parts of Northern Italy following the introduction of North American invasive grey squirrels (Sciurus carolinensis). We extracted glucocorticoid metabolites from faecal samples to measure whether the presence of the invasive species causes an increase in physiological stress in individuals of the native species. We show that native red squirrels in seven sites where they co-occurred with invasive grey squirrels had glucocorticoid concentrations that were three times higher than those in five sites without the invasive species. Moreover, in a longitudinal study, stress hormones in native red squirrels increased after colonisation by grey squirrels. When we experimentally reduced the abundance of the invasive grey squirrels, the concentration of faecal glucocorticoid metabolites in co-occurring red squirrels decreased significantly between pre- and postremoval periods. Hence, we found that the invasive species acts as a stressor which significantly increases the concentrations of glucocorticoids in the native species. Given that sustained elevations in glucocorticoids could reduce body growth and reproductive rate, our results are consistent with previous studies where the co-occurrence of the invasive grey squirrel was associated with smaller size and lower reproductive output in red squirrels. © 2018 The Authors. Journal of Animal Ecology © 2018 British Ecological Society.

Delayed effect of pinealectomy on hibernation of the golden-mantled ground squirrel

NASA Astrophysics Data System (ADS)

Ralph, C. L.; Harlow, H. J.; Phillips, J. A.

1982-12-01

Pinealectomy or radical sham pinealectomy were performed on adult golden-mantled ground squirrels, Spermophilus (=Citellus) lateralis, approximately 1 month prior to the date of normal winter emergence. The first hibernatory period and subsequent active season were not different in either of the operated groups from intact animals. However, although the initiation of the second hibernatory period was not affected in the pinealectomized animals, this group failed to show the progressive increase in the length of heterothermic bouts that is characteristic of normal hibernation. Also, terminal arousal occurred approximately 6 weeks earlier in the second year after pinealectomy. Male squirrels showed a corresponding time compression in their annual gonadal cycle, as was assessed by testicular state. These results suggest that the pineal gland of the golden-mantled ground squirrel is involved in the expression of the annual hibernatory cycle. In the absence of the pineal gland the adult of this species is unable to sustain the normal depth and duration of hibernation in the second over-wintering period following pinealectomy. We have carried out additional experiments with young, laboratory-born S. lateralis and with field-caught, adult S. richardsonii. The results of these studies also are described in this paper.

Generation of transgenic monkeys with human inherited genetic disease.

PubMed

Chan, Anthony W S; Yang, Shang-Hsun

2009-09-01

Modeling human diseases using nonhuman primates including chimpanzee, rhesus, cynomolgus, marmoset and squirrel monkeys has been reported in the past decades. Due to the high similarity between nonhuman primates and humans, including genome constitution, cognitive behavioral functions, anatomical structure, metabolic, reproductive, and brain functions; nonhuman primates have played an important role in understanding physiological functions of the human body, clarifying the underlying mechanism of human diseases, and the development of novel treatments for human diseases. However, nonhuman primate research has been restricted to cognitive, behavioral, biochemical and pharmacological approaches of human diseases due to the limitation of gene transfer technology in nonhuman primates. The recent advancement in transgenic technology that has led to the generation of the first transgenic monkey in 2001 and a transgenic monkey model of Huntington's disease (HD) in 2008 has changed that focus. The creation of transgenic HD monkeys that replicate key pathological features of human HD patients further suggests the crucial role of nonhuman primates in the future development of biomedicine. These successes have opened the door to genetic manipulation in nonhuman primates and a new era in modeling human inherited genetic disorders. We focused on the procedures in creating transgenic Huntington's disease monkeys, but our work can be applied to transgenesis in other nonhuman primate species.

Somatic and neuroendocrine responses to standard and biologically salient acoustic startle stimuli in monkeys

PubMed Central

Parker, Karen J.; Hyde, Shellie A.; Buckmaster, Christine L.; Tanaka, Serena M.; Brewster, Katharine K.; Schatzberg, Alan F.; Lyons, David M.; Woodward, Steven H.

2010-01-01

SUMMARY The startle response, a simple defensive response to a sudden stimulus signaling proximal threat, has been well studied in rodents and humans, but has been rarely examined in monkeys. The first goal of the present studies was to develop a minimally immobilizing startle measurement paradigm and validate its usefulness by testing two core features of the startle response (habituation and graded responsivity) in squirrel monkey subjects. Two different types of startle stimuli were used: standard broad-band noise bursts, and species-specific alarm vocalizations (“yaps”) which are elicited in response to threat in both wild and captive animals. The second goal of the present studies was to test whether yaps produce enhanced startle responsivity due to their increased biological salience compared to simple, non-biologically relevant noise bursts. The third goal of the present studies was to evaluate the hypothalamic pituitary-adrenal (HPA) axis response to startle stimuli, as little is known about the stress-activating role of startle stimuli in any species. These experiments determined that the whole-body startle response in relatively unrestrained squirrel monkeys habituates across repeated stimulus presentations and is proportional to stimulus intensity. In addition, differential habituation was observed across biologically salient vs. standard acoustic startle stimuli. Responses to “yaps” were larger initially but attenuated more rapidly over trials. Responses to “yaps” were also larger in the early subepochs of the response window but then achieved a lower level than responses to noise bursts in the later subepochs. Finally, adrenocorticotropic hormone and cortisol concentrations were significantly elevated above baseline after startle stimuli presentation, though monkeys did not exhibit differential HPA axis responses to the two types of startle stimuli. The development of monkey startle methodology may further enhance the utility of this

Evidence for West Nile virus spillover into the squirrel population in Atlanta, Georgia.

PubMed

Bisanzio, Donal; McMillan, Joseph R; Barreto, Josafá Gonçalves; Blitvich, Bradley J; Mead, Daniel G; O'Connor, Josh; Kitron, Uriel

2015-05-01

In the United States, spillover of West Nile virus (WNV) into wild mammal populations has been reported since the introduction of the virus into the New World in 1999. Eastern gray squirrels (Sciurus carolinensis) exhibit a high seroprevalence for WNV in urban settings where high virus circulation and human spillover have been reported. In Atlanta, Georgia, human cases of WNV are uncommon despite high infection rates in birds and mosquitoes. In this study, we evaluated WNV exposure of eastern gray squirrels in a WNV hot spot in Atlanta. Gray squirrels were live-trapped in Grant Park, Atlanta, during July-October, 2012, and a census was conducted to estimate squirrel density in the study site. Sera from trapped animals were tested for circulating virus-by-virus isolation in cell culture and for WNV-specific antibodies by enzyme-linked immunosorbent assay and plaque reduction neutralization test. Mosquitoes were collected at the same location and tested for virus isolation. Among the 69 collected squirrels, 25 (36.2%) tested positive for WNV antibodies, although none were viremic. Seroprevalence was lower in juveniles (18.8%) than in adults (37.5%), but this difference was not statistically significant. Gender and squirrel density had no effect on seroprevalence. Seasonality of squirrel seroprevalence and of mosquito infection were significantly associated, both peaking in August. No difference in squirrel exposure was detected across the collection sites. We report a high degree of WNV exposure in squirrels in Grant Park that was correlated with seasonality of mosquito infection. The detection of antibodies in juveniles suggests that circulation of WNV in the surveyed population is ongoing. Eastern gray squirrels may be suitable indicators for virus amplification and for risk of human spillover on a local scale in urban settings.

The major histocompatibility complex of tassel-eared squirrels. II. Genetic diversity associated with Abert squirrels.

PubMed

Wettstein, P J; States, J S

1986-01-01

The extent of polymorphism and the rate of divergence of class I and class II sequences mapping to the mammalian major histocompatibility complex (MHC) have been the subject of experimentation and speculation. To provide further insight into the evolution of the MHC we have initiated the analysis of two geographically isolated subspecies of tassel-eared squirrels. In the preceding communication we described the number and polymorphism of TSLA class I and class II sequences in Kaibab squirrels (S. aberti kaibabensis), which live north of the Grand Canyon. In this report we present a parallel analysis of Abert squirrels (S. aberti aberti), which live south of the Grand Canyon in northern Arizona. Genomic DNA from 12 Abert squirrels was digested with restriction enzymes, electrophoresed, blotted, and hybridized with DR alpha, DR beta, DQ alpha, DQ beta, and HLA-B7 probes. The results of these hybridizations were remarkably similar to those obtained in Kaibab squirrels. The majority of class I and class II bands were identical in size and number, suggesting that Abert and Kaibab squirrels have not significantly diverged in the TSLA complex despite their geographical separation. Relative polymorphism of class II sequences was similar to that observed with Kaibab squirrels: beta sequences exhibited higher polymorphism than alpha sequences. As in Kaibab squirrels, a number of alpha and beta sequences were apparently carried on the same fragments. In comparison to class II beta sequences, there was limited polymorphism in class I sequences, although a diverse number of class I genotypes were observed. Attempts to identify segregating TSLA haplotypes were futile in that the only families of sequences with concordant distributions were DQ alpha and DQ beta. These observations and those obtained with Kaibab squirrels suggest that the present-day TSLA haplotypes of both subspecies are derived from a limited number of common, progenitor haplotypes through repeated intra

The 14/15 association as a paradigmatic example of tracing karyotype evolution in New World monkeys.

PubMed

Capozzi, Oronzo; Archidiacono, Nicoletta; Lorusso, Nicola; Stanyon, Roscoe; Rocchi, Mariano

2016-09-01

Fluorescence in situ hybridization (FISH), especially chromosome painting, has been extensively exploited in the phylogenetic reconstruction of primate evolution. Although chromosome painting is a key method to map translocations, it is not effective in detecting chromosome inversions, which may be up to four times more frequent than other chromosomal rearrangements. BAC-FISH instead can economically delineate marker order and reveal intrachromosomal rearrangements. However, up to now, BAC-FISH was rarely used to study the chromosomes of New World monkeys partly due to technical difficulties. In this paper, we used BAC-FISH to disentangle the complex evolutionary history of the ancestral 14/15 association in NWMs, beginning from the squirrel monkey (Saimiri boliviensis). To improve the hybridization efficiency of BAC-FISH in NWMs, we "translated" the human BACs into Callithrix jacchus (CJA) BACs, which yielded much higher hybridization efficiencies on other NWM species than human BACs. Our results disclosed 14 synteny blocks in squirrel monkeys, 7 more than with chromosome painting. We then applied a subset of CJA BACs on six other NWM species. The comparison of the hybridization pattern of these species contained phylogenetic information to discriminate evolutionary relationships. Notably Aotus was found to share an inversion with Callithrix, thus definitely assigning the genus Aotus to Cebidae. The present study can be seen as a paradigmatic approach to investigate the phylogenetics of NWMs by molecular cytogenetics.

Fox squirrels (Sciurus niger) develop West Nile virus viremias sufficient for infecting select mosquito species.

PubMed

Platt, Kenneth B; Tucker, Brad J; Halbur, Patrick G; Blitvich, Bradley J; Fabiosa, Flor G; Mullin, Kathleen; Parikh, Grishma R; Kitikoon, Pravina; Bartholomay, Lyric C; Rowley, Wayne A

2008-04-01

The West Nile virus (WNV) viremia and shedding profiles of 11 adult fox squirrels (Sciurus niger) infected by needle inoculation or mosquito bite were characterized. Daily mean titers (95% confidence intervals) for all squirrels on days 1 through 6 postexposure (p.e.) were: 10(1.7 (1.32.1)), 10(4.4 (4.04.8)), 10(5.3 (5.05.6)), 10(4.4 (3.94.9)), 10(2.7 (2.03.4)), and 10(1.1 (0.52.1)) plaque-forming units (PFU)/mL. The highest WNV serum titers of individual squirrels infected by needle inoculation or mosquito bite ranged from 10(4.5) to 10(6.1) and from 10(5.1) to 10(5.3) PFU/mL, respectively. Nine (82%) squirrels, including all 4 squirrels infected by mosquito bite, had WNV serum titers > or =10(5.1) PFU/mL that persisted on average for 1.6 +/- 0.3 days. Infection and dissemination rates of Culex pipiens (L.) that fed on squirrels with serum titers of 10(4.4 +/- 0.1) PFU/mL were 56% and 13%, respectively. Both of these rates increased to over 80% when fed on squirrels with a mean WNV titer of 10(5.5 +/- 0.1) PFU/mL. Infection and dissemination also occurred in Aedes triseriatus (Say) but at a much lower rate. WNV was isolated from the oral and rectal cavities of all squirrels and from urine that was opportunistically collected from 5 squirrels. The largest quantity of WNV recovered from swabs of the oral cavity and urine was 10(3.1) PFU. The longest periods after exposure that WNV was isolated from the oral cavity and urine from a squirrel were 22 and 17 days p.e., respectively. WNV RNA was also detected in kidney tissue in 1 squirrel 29 days p.e., suggesting that fox squirrels can be persistently infected. Collectively these observations provide further evidence that squirrels can contribute to the natural history and epidemiology of WNV, especially in peridomestic environments.

Dynamics of squirrel monkey linear vestibuloocular reflex and interactions with fixation distance.

PubMed

Telford, L; Seidman, S H; Paige, G D

1997-10-01

Horizontal, vertical, and torsional eye movements were recorded using the magnetic search-coil technique during linear accelerations along the interaural (IA) and dorsoventral (DV) head axes. Four squirrel monkeys were translated sinusoidally over a range of frequencies (0.5-4.0 Hz) and amplitudes (0.1-0.7 g peak acceleration). The linear vestibuloocular reflex (LVOR) was recorded in darkness after brief presentations of visual targets at various distances from the subject. With subjects positioned upright or nose-up relative to gravity, IA translations generated conjugate horizontal (IA horizontal) eye movements, whereas DV translations with the head nose-up or right-side down generated conjugate vertical (DV vertical) responses. Both were compensatory for linear head motion and are thus translational LVOR responses. In concert with geometric requirements, both IA-horizontal and DV-vertical response sensitivities (in deg eye rotation/cm head translation) were related linearly to reciprocal fixation distance as measured by vergence (in m-1, or meter-angles, MA). The relationship was characterized by linear regressions, yielding sensitivity slopes (in deg.cm-1.MA-1) and intercepts (sensitivity at 0 vergence). Sensitivity slopes were greatest at 4.0 Hz, but were only slightly more than half the ideal required to maintain fixation. Slopes declined with decreasing frequency, becoming negligible at 0.5 Hz. Small responses were observed when vergence was zero (intercept), although no response is required. Like sensitivity slope, the intercept was largest at 4.0 Hz and declined with decreasing frequency. Phase lead was near zero (compensatory) at 4.0 Hz, but increased as frequency declined. Changes in head orientation, motion axis (IA vs. DV), and acceleration amplitude produced slight and sporadic changes in LVOR parameters. Translational LVOR response characteristics are consistent with high-pass filtering within LVOR pathways. Along with horizontal eye movements, IA

Behavioral Determinants of Cannabinoid Self-Administration in Old World Monkeys.

PubMed

John, William S; Martin, Thomas J; Nader, Michael A

2017-06-01

Reinforcing effects of Δ 9 -tetrahydrocannabinol (THC), the primary active ingredient in marijuana, as assessed with self-administration (SA), has only been established in New World primates (squirrel monkeys). The objective of this study was to investigate some experimental factors that may enhance intravenous SA of THC and the cannabinoid receptor (CBR) agonist CP 55 940 in Old World monkeys (rhesus and cynomolgus), a species that has been used extensively in biomedical research. In one experiment, male rhesus monkeys (N=9) were trained to respond under a fixed-ratio 10 schedule of food presentation. The effects of CP 55 940 (1.0-10 μg/kg, i.v.) and THC (3.0-300 μg/kg, i.v.) on food-maintained responding and body temperature were determined in these subjects prior to giving them access to self-administer each drug. Both drugs dose-dependently decreased food-maintained responding. CP 55 940 (0.001-3.0 μg/kg) functioned as a reinforcer in three monkeys, whereas THC (0.01-10 μg/kg) did not have reinforcing effects in any subject. CP 55 940 was least potent to decrease food-maintained responding in the monkeys in which CP 55 940 functioned as a reinforcer. Next, THC was administered daily to monkeys until tolerance developed to rate-decreasing effects. When THC SA was reexamined, it functioned as a reinforcer in three monkeys. In a group of cocaine-experienced male cynomolgus monkeys (N=4), THC SA was examined under a second-order schedule of reinforcement; THC functioned as reinforcer in two monkeys. These data suggest that SA of CBR agonists may be relatively independent of their rate-decreasing effects in Old World monkeys. Understanding individual differences in vulnerability to THC SA may lead to novel treatment strategies for marijuana abuse.

Ground squirrel tail-flag displays alter both predatory strike and ambush site selection behaviours of rattlesnakes.

PubMed

Barbour, Matthew A; Clark, Rulon W

2012-09-22

Many species approach, inspect and signal towards their predators. These behaviours are often interpreted as predator-deterrent signals--honest signals that indicate to a predator that continued hunting is likely to be futile. However, many of these putative predator-deterrent signals are given when no predator is present, and it remains unclear if and why such signals deter predators. We examined the effects of one such signal, the tail-flag display of California ground squirrels, which is frequently given both during and outside direct encounters with northern Pacific rattlesnakes. We video-recorded and quantified the ambush foraging responses of rattlesnakes to tail-flagging displays from ground squirrels. We found that tail-flagging deterred snakes from striking squirrels, most likely by advertising squirrel vigilance (i.e. readiness to dodge a snake strike). We also found that tail-flagging by adult squirrels increased the likelihood that snakes would leave their ambush site, apparently by elevating the vigilance of nearby squirrels which reduces the profitability of the ambush site. Our results provide some of the first empirical evidence of the mechanisms by which a prey display, although frequently given in the absence of a predator, may still deter predators during encounters.

Characterization of the Sweet Taste Receptor Tas1r2 from an Old World Monkey Species Rhesus Monkey and Species-Dependent Activation of the Monomeric Receptor by an Intense Sweetener Perillartine

PubMed Central

Cai, Chenggu; Jiang, Hua; Li, Lei; Liu, Tianming; Song, Xuejie; Liu, Bo

2016-01-01

Sweet state is a basic physiological sensation of humans and other mammals which is mediated by the broadly acting sweet taste receptor-the heterodimer of Tas1r2 (taste receptor type 1 member 2) and Tas1r3 (taste receptor type 1 member 3). Various sweeteners interact with either Tas1r2 or Tas1r3 and then activate the receptor. In this study, we cloned, expressed and functionally characterized the taste receptor Tas1r2 from a species of Old World monkeys, the rhesus monkey. Paired with the human TAS1R3, it was shown that the rhesus monkey Tas1r2 could respond to natural sugars, amino acids and their derivates. Furthermore, similar to human TAS1R2, rhesus monkey Tas1r2 could respond to artificial sweeteners and sweet-tasting proteins. However, the responses induced by rhesus monkey Tas1r2 could not be inhibited by the sweet inhibitor amiloride. Moreover, we found a species-dependent activation of the Tas1r2 monomeric receptors of human, rhesus monkey and squirrel monkey but not mouse by an intense sweetener perillartine. Molecular modeling and sequence analysis indicate that the receptor has the conserved domains and ligand-specific interactive residues, which have been identified in the characterized sweet taste receptors up to now. This is the first report of the functional characterization of sweet taste receptors from an Old World monkey species. PMID:27479072

Characterization of the Sweet Taste Receptor Tas1r2 from an Old World Monkey Species Rhesus Monkey and Species-Dependent Activation of the Monomeric Receptor by an Intense Sweetener Perillartine.

PubMed

Cai, Chenggu; Jiang, Hua; Li, Lei; Liu, Tianming; Song, Xuejie; Liu, Bo

2016-01-01

Sweet state is a basic physiological sensation of humans and other mammals which is mediated by the broadly acting sweet taste receptor-the heterodimer of Tas1r2 (taste receptor type 1 member 2) and Tas1r3 (taste receptor type 1 member 3). Various sweeteners interact with either Tas1r2 or Tas1r3 and then activate the receptor. In this study, we cloned, expressed and functionally characterized the taste receptor Tas1r2 from a species of Old World monkeys, the rhesus monkey. Paired with the human TAS1R3, it was shown that the rhesus monkey Tas1r2 could respond to natural sugars, amino acids and their derivates. Furthermore, similar to human TAS1R2, rhesus monkey Tas1r2 could respond to artificial sweeteners and sweet-tasting proteins. However, the responses induced by rhesus monkey Tas1r2 could not be inhibited by the sweet inhibitor amiloride. Moreover, we found a species-dependent activation of the Tas1r2 monomeric receptors of human, rhesus monkey and squirrel monkey but not mouse by an intense sweetener perillartine. Molecular modeling and sequence analysis indicate that the receptor has the conserved domains and ligand-specific interactive residues, which have been identified in the characterized sweet taste receptors up to now. This is the first report of the functional characterization of sweet taste receptors from an Old World monkey species.

Fetal, infant, adolescent and adult phenotypes of polycystic ovary syndrome in prenatally androgenized female rhesus monkeys

PubMed Central

Abbott, David H; Tarantal, Alice F; Dumesic, Daniel A

2010-01-01

Old World monkeys provide naturally-occurring and experimentally-induced phenotypes closely resembling the highly prevalent polycystic ovary syndrome (PCOS) in women. In particular, experimentally-induced fetal androgen excess in female rhesus monkeys produces a comprehensive adult PCOS-like phenotype that includes both reproductive and metabolic dysfunction found in PCOS women. Such a reliable experimental approach enables the use of the prenatally androgenized (PA) female rhesus monkey model to (1) examine fetal, infant and adolescent antecedents of adult pathophysiology, gaining valuable insight into early phenotypic expression of PCOS, and (2) to understand adult pathophysiology from a mechanistic perspective. Elevated circulating luteinizing hormone (LH) levels are the earliest indication of reproductive dysfunction in late gestation nonhuman primate fetuses and infants exposed to androgen excess during early (late first to second trimester) gestation. Such early gestation-exposed PA infants also are hyperandrogenic, with both LH hypersecretion and hyperandrogenism persisting in early gestation-exposed PA adults. Similarly, subtle metabolic abnormalities appearing in young nonhuman primate infants and adolescents precede the abdominal adiposity, hyperliplidemia, and increased incidence of type 2 diabetes that characterize early gestated-exposed PA adults. These new insights into the developmental origins of PCOS, and progression of the pathophysiology from infancy to adulthood, provide opportunities for clinical intervention to ameliorate the PCOS phenotype thus providing a preventive health care approach to PCOS-related abnormalities. For example, PCOS-like traits in PA monkeys, as in PCOS women, can improve with better insulin-glucose homeostasis, suggesting that lifestyle interventions preventing increased adiposity in adolescent daughters of PCOS mothers also may reduce their risk of acquiring many PCOS-related metabolic abnormalities in adulthood. PMID

Prevalence of antibody to adult T-cell leukemia virus-associated antigens (ATLA) in Japanese monkeys and other non-human primates.

PubMed

Hayami, M; Komuro, A; Nozawa, K; Shotake, T; Ishikawa, K; Yamamoto, K; Ishida, T; Honjo, S; Hinuma, Y

1984-02-15

The prevalence of adult T-cell-leukemia virus (ATLV) infection was examined in Japanese monkeys living naturally in various parts of Japan and in other species of non-human primates imported into and kept in Japan. Sera of 2,650 Japanese monkeys from 41 troops throughout Japan were tested. High incidences of anti-ATLV-associated antigen (ATLA)-positive monkeys were found in most troops, not only in the endemic area of human ATL(Southwestern Japan), but also in non-endemic areas. The incidence of sero-positive individuals increased gradually with age, reaching a maximum when the animals became adult, indicating age dependency, like that found by epidemiological studies on humans. Anti-ATLA antibodies were also detected in 90 of 815 sera of imported non-human primates of 33 species other than Japanese monkeys. All the anti-ATLA sero-positive monkeys were Catarrhines (Old World monkeys), mainly macaques of Asian origin. Some sero-positive monkeys were also found among animals of African origin, but no antibody was detected in Prosimians and Platyrrhines (New World monkeys). The clear-cut difference between the geographical distribution of sero-positive simians and that of humans indicates the improbability of direct transmission of ATLV from simians to humans.

Home range, social behavior, and dominance relationships in the African unstriped ground squirrel, Xerus rutilus

USGS Publications Warehouse

O'Shea, Thomas J.

1976-01-01

A field study of home range, social behavior, and dominance relationships in the African unstriped ground squirrel, Xerus rutilus, was conducted in semi-arid bushland near Kibwezi, Kenya. Ground squirrels lived alone or in small groups in isolated burrow systems and had broadly overlapping home ranges. They were neither territorial or colonial. Home ranges were estimated by visual observation of marked animals and those of males were considerably larger (mean=7.01 hectares (ha); n=4) than those of females (mean=1.37 ha; n-6). A continuum of agonistic behavior ranging from threat to combat is described, although actual combat was rarely observed. Sexual behavior includes a stereotypical tail display by adult males. Dominance relationships, based on 542 observed encounters between marked individuals, include a consistent male dominance over females and a fairly constant linear hierarchy among all individuals with shared home ranges. Similarities in the behavior of African ground squirrels and tree squirrels (Sciurus) are discussed.

Effects of Serotonin 2C Receptor Agonists on the Behavioral and Neurochemical Effects of Cocaine in Squirrel Monkeys

PubMed Central

Manvich, Daniel F.; Kimmel, Heather L.

2012-01-01

Accumulating evidence indicates that the serotonin system modulates the behavioral and neurochemical effects of cocaine, but the receptor subtypes mediating these effects remain unknown. Recent studies have demonstrated that pharmacological activation of the serotonin 2C receptor (5-HT2CR) attenuates the behavioral and neurochemical effects of cocaine in rodents, but such compounds have not been systematically evaluated in nonhuman primates. The present experiments sought to determine the impact of pretreatment with the preferential 5-HT2CR agonist m-chlorophenylpiperazine (mCPP) and the selective 5-HT2CR agonist Ro 60-0175 [(α-S)-6-chloro-5-fluoro-α-methyl-1H-indole-1-ethanamine fumarate] on the behavioral and neurochemical effects of cocaine in squirrel monkeys. In subjects trained to lever-press according to a 300-s fixed-interval schedule of stimulus termination, pretreatment with either 5-HT2CR agonist dose-dependently and insurmountably attenuated the behavioral stimulant effects of cocaine. In subjects trained to self-administer cocaine, both compounds dose-dependently and insurmountably attenuated cocaine-induced reinstatement of previously extinguished responding in an antagonist-reversible manner, and the selective agonist Ro 60-0175 also attenuated the reinforcing effects of cocaine during ongoing cocaine self-administration. It is noteworthy that the selective agonist Ro 60-0175 exhibited behavioral specificity because it did not significantly alter nondrug-maintained responding. Finally, in vivo microdialysis studies revealed that pretreatment with Ro 60-0175 caused a reduction of cocaine-induced dopamine increases within the nucleus accumbens, but not the caudate nucleus. These results suggest that 5-HT2CR agonists functionally antagonize the behavioral effects of cocaine in nonhuman primates, possibly via a selective modulation of cocaine-induced dopamine increases within the mesolimbic dopamine system and may therefore represent a novel class of

Horizontal vestibuloocular reflex evoked by high-acceleration rotations in the squirrel monkey. IV. Responses after spectacle-induced adaptation

NASA Technical Reports Server (NTRS)

Clendaniel, R. A.; Lasker, D. M.; Minor, L. B.; Shelhamer, M. J. (Principal Investigator)

2001-01-01

The horizontal angular vestibuloocular reflex (VOR) evoked by sinusoidal rotations from 0.5 to 15 Hz and acceleration steps up to 3,000 degrees /s(2) to 150 degrees /s was studied in six squirrel monkeys following adaptation with x2.2 magnifying and x0.45 minimizing spectacles. For sinusoidal rotations with peak velocities of 20 degrees /s, there were significant changes in gain at all frequencies; however, the greatest gain changes occurred at the lower frequencies. The frequency- and velocity-dependent gain enhancement seen in normal monkeys was accentuated following adaptation to magnifying spectacles and diminished with adaptation to minimizing spectacles. A differential increase in gain for the steps of acceleration was noted after adaptation to the magnifying spectacles. The gain during the acceleration portion, G(A), of a step of acceleration (3,000 degrees /s(2) to 150 degrees /s) increased from preadaptation values of 1.05 +/- 0.08 to 1.96 +/- 0.16, while the gain during the velocity plateau, G(V), only increased from 0.93 +/- 0.04 to 1.36 +/- 0.08. Polynomial fits to the trajectory of the response during the acceleration step revealed a greater increase in the cubic than the linear term following adaptation with the magnifying lenses. Following adaptation to the minimizing lenses, the value of G(A) decreased to 0.61 +/- 0.08, and the value of G(V) decreased to 0.59 +/- 0.09 for the 3,000 degrees /s(2) steps of acceleration. Polynomial fits to the trajectory of the response during the acceleration step revealed that there was a significantly greater reduction in the cubic term than in the linear term following adaptation with the minimizing lenses. These findings indicate that there is greater modification of the nonlinear as compared with the linear component of the VOR with spectacle-induced adaptation. In addition, the latency to the onset of the adapted response varied with the dynamics of the stimulus. The findings were modeled with a bilateral model

Ground squirrel tail-flag displays alter both predatory strike and ambush site selection behaviours of rattlesnakes

PubMed Central

Barbour, Matthew A.; Clark, Rulon W.

2012-01-01

Many species approach, inspect and signal towards their predators. These behaviours are often interpreted as predator-deterrent signals—honest signals that indicate to a predator that continued hunting is likely to be futile. However, many of these putative predator-deterrent signals are given when no predator is present, and it remains unclear if and why such signals deter predators. We examined the effects of one such signal, the tail-flag display of California ground squirrels, which is frequently given both during and outside direct encounters with northern Pacific rattlesnakes. We video-recorded and quantified the ambush foraging responses of rattlesnakes to tail-flagging displays from ground squirrels. We found that tail-flagging deterred snakes from striking squirrels, most likely by advertising squirrel vigilance (i.e. readiness to dodge a snake strike). We also found that tail-flagging by adult squirrels increased the likelihood that snakes would leave their ambush site, apparently by elevating the vigilance of nearby squirrels which reduces the profitability of the ambush site. Our results provide some of the first empirical evidence of the mechanisms by which a prey display, although frequently given in the absence of a predator, may still deter predators during encounters. PMID:22787023

Squirrel Foraging Preferences: Gone Nuts?

ERIC Educational Resources Information Center

Darling, Randi A.

2007-01-01

This field exercise examines the feeding preferences of Gray Squirrels ("Sciurus carolinensis"). Students present squirrels with a variety of food types in a cafeteria-style arrangement in order to test hypotheses about foraging preferences. This exercise, which is appropriate for introductory biology, ecology, and animal behavior classes, is…

Torsional Eye Movements Evoked by Unilateral Labyrinthine Galvanic Polarizations in the Squirrel Monkey

NASA Technical Reports Server (NTRS)

Minor, Lloyd B.; Tomko, David L.; Paige, Gary D.

1995-01-01

longer periods of current administration. This adaptation is manifested as a perstimulus return toward resting discharge and poststimulus after-response in the opposite direction (Goldberg et al., 1984; Minor and Goldberg, l991). Cathodal currents (with respect to the perilymphatic space of the vestibule) are excitatory whereas anodal currents are inhibitory. Horizontal eye movements evoked by unilateral galvanic polarizations administered through chronically implanted labyrinthine stimulating electrodes have been studied in alert squirrel monkeys (Minor and Goldberg, 1991). We sought to extend this analysis by recording three-dimensional eye movements during galvanic stimulation. As predicted based upon roughly equal stimulation of ampullary nerves innervating the vertical canals, a substantial torsional component to the nystagmus is noted. The trajectory of torsional slow phases and nystagmus profile after the polarization provide insight into the central mechanisms that influence these responses.

Multiple detection of zoonotic variegated squirrel bornavirus 1 RNA in different squirrel species suggests a possible unknown origin for the virus.

PubMed

Schlottau, Kore; Hoffmann, Bernd; Homeier-Bachmann, Timo; Fast, Christine; Ulrich, Rainer G; Beer, Martin; Hoffmann, Donata

2017-09-01

The recently discovered variegated squirrel bornavirus 1 (VSBV-1) caused the death of three squirrel breeders in Germany. Subsequent first screening of squirrels with in vivo collected swab samples and a VSBV-1-specific RT-qPCR revealed not only variegated squirrel infections (Sciurus variegatoides), but also Prevost's squirrels (Callosciurus prevostii) as positive for VSBV-1 genome. In this study, 328 squirrels were tested using the established RT-qPCR assays. In 16 individual animals VSBV-1 RNA could be detected; 15 individuals were from small breedings and zoological gardens in Germany, with the remaining individual being from a zoological garden in Croatia. Positive animals belonged to the species C. prevostii, C. finlaysonii, and Tamiops swinhoei within the subfamily Callosciurinae and Sciurus granatensis within the subfamily Sciurinae. Repeated non-invasive oral swab sampling in one holding indicated positive animals months after a first negative result. Besides the oral swabs, VSBV-1 was also detected in fecal (pool) samples allowing the future monitoring of squirrel holdings based on RT-qPCR investigation of such samples. The detection in zoological gardens emphasizes the need for further investigations into the transmission route to humans in order to develop rational public health measures for prevention of transmission. Finally, the detection of several closely related VSBV-1 sequences in squirrels from different subfamilies raises questions as to the origin of the virus.

Cell-poor septa separate representations of digits in the ventroposterior nucleus of the thalamus in monkeys and prosimian galagos.

PubMed

Qi, Hui-Xin; Gharbawie, Omar A; Wong, Peiyan; Kaas, Jon H

2011-03-01

The architectonic features of the ventroposterior nucleus (VP) were visualized in coronal brain sections from two macaque monkeys, two owl monkeys, two squirrel monkeys, and three galagos that were processed for cytochrome oxidase, Nissl bodies, or the vesicular glutamate transporter 2 (vGluT2). The traditional ventroposterior medial (VPM) and ventroposterior lateral (VPL) subnuclei were easily identified, as well as the forelimb and hindlimb compartments of VPL, as they were separated by poorly staining, cell-poor septa. Septa also separated other cell groups within VPM and VPL, specifically in the medial compartment of VPL representing the hand (hand VPL). In one squirrel monkey and one galago we demonstrated that these five groups of cells represent digits 1-5 in a mediolateral sequence by injecting tracers into the cortical representation of single digits, defined by microelectrode recordings, and relating concentrations of labeled neurons to specific cell groups in hand VPL. The results establish the existence of septa that isolate the representation of the five digits in VPL of primates and demonstrate that the isolated cell groups represent digits 1-5 in a mediolateral sequence. The present results show that the septa are especially prominent in brain sections processed for vGluT2, which is expressed in the synaptic terminals of excitatory neurons in most nuclei of the brainstem and thalamus. As vGluT2 is expressed in the synaptic terminations from dorsal columns and trigeminal brainstem nuclei, the effectiveness of vGluT2 preparations in revealing septa in VP likely reflects a lack of synapses using glutamate in the septa. Copyright © 2010 Wiley-Liss, Inc.

Cell-Poor Septa Separate Representations of Digits in the Ventroposterior Nucleus of the Thalamus in Monkeys and Prosimian Galagos

PubMed Central

Qi, Hui-Xin; Gharbawie, Omar A.; Wong, Peiyan; Kaas, Jon H.

2013-01-01

The architectonic features of the ventroposterior nucleus (VP) were visualized in coronal brain sections from two macaque monkeys, two owl monkeys, two squirrel monkeys, and three galagos that were processed for cytochrome oxidase, Nissl bodies, or the vesicular glutamate transporter 2 (vGluT2). The traditional ventroposterior medial (VPM) and ventroposterior lateral (VPL) subnuclei were easily identified, as well as the forelimb and hindlimb compartments of VPL, as they were separated by poorly staining, cell-poor septa. Septa also separated other cell groups within VPM and VPL, specifically in the medial compartment of VPL representing the hand (hand VPL). In one squirrel monkey and one galago we demonstrated that these five groups of cells represent digits 1–5 in a mediolateral sequence by injecting tracers into the cortical representation of single digits, defined by microelectrode recordings, and relating concentrations of labeled neurons to specific cell groups in hand VPL. The results establish the existence of septa that isolate the representation of the five digits in VPL of primates and demonstrate that the isolated cell groups represent digits 1–5 in a mediolateral sequence. The present results show that the septa are especially prominent in brain sections processed for vGluT2, which is expressed in the synaptic terminals of excitatory neurons in most nuclei of the brainstem and thalamus. As vGluT2 is expressed in the synaptic terminations from dorsal columns and trigeminal brainstem nuclei, the effectiveness of vGluT2 preparations in revealing septa in VP likely reflects a lack of synapses using glutamate in the septa. J. Comp. Neurol. 519:738–758, 2011. PMID:21246552

Biodiversity threats from outside to inside: effects of alien grey squirrel (Sciurus carolinensis) on helminth community of native red squirrel (Sciurus vulgaris).

PubMed

Romeo, Claudia; Ferrari, Nicola; Lanfranchi, Paolo; Saino, Nicola; Santicchia, Francesca; Martinoli, Adriano; Wauters, Lucas A

2015-07-01

Biological invasions are among the major causes of biodiversity loss worldwide, and parasites carried or acquired by invaders may represent an added threat to native species. We compared gastrointestinal helminth communities of native Eurasian red squirrels (Sciurus vulgaris) in the presence and absence of introduced Eastern grey squirrels (Sciurus carolinensis) to detect alterations induced by the alien species. In particular, we investigated whether spillover of a North American nematode Strongyloides robustus occurs and whether prevalence of a local parasite Trypanoxyuris sciuri in red squirrels is affected by grey squirrel presence. The probability of being infected by both parasites was significantly higher in areas co-inhabited by the alien species, where 61 % of examined red squirrels (n = 49) were infected by S. robustus and 90 % by T. sciuri. Conversely, in red-only areas, the two parasites infected only 5 and 70 % of individuals (n = 60). Overall, our findings support the hypothesis that red squirrels acquire S. robustus via spillover from the alien congener and suggest that invaders' presence may also indirectly affect infection by local parasites through mechanisms diverse than spill-back and linked to the increased competitive pressure to which red squirrels are subjected. These results indicate that the impact of grey squirrel on red squirrels may have been underestimated and highlight the importance of investigating variation in macroparasite communities of native species threatened by alien competitors.

Aged monkeys as a partial model for Parkinson's disease

PubMed Central

Hurley, P.J.; Elsworth, J.D.; Whittaker, M.C.; Roth, R.H.; Redmond, D.E.

2011-01-01

Parkinson's Disease (PD) and the natural aging process share a number of biochemical mechanisms, including reduced function of dopaminergic systems. The present study aims to determine the extent that motor and behavioral changes in aged monkeys resemble parkinsonism induced by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. The behavioral and physiological changes in PD are believed to result largely from selective depletion of dopamine in the nigrostriatal system. In the present study, ten aged female monkeys were compared with three groups: 9 untreated young adult female monkeys, 10 young adult male monkeys and 13 older male monkeys that had been exposed to MPTP. Trained observers, blind as to age and drug condition and without knowledge of the hypotheses, scored the monkeys using the Parkinson's factor score (Parkscore), which has been validated by a high correlation with post mortem striatal dopamine (DA) concentrations. The aged animals had higher scores on the Parkscore compared with the young adults, with most of its component behavioral items showing significance (tremor, eating problems, delayed initiation of movement, and poverty of movement). L-Dopa and DA-agonists did not clearly reverse the principal measure of parkinsonism. DA concentrations post mortem were 63% lower in 3 aged monkeys in the ventral putamen compared with 4 young adults, with greater reductions in putamen than in caudate (45%). We conclude that aged monkeys, unexposed to MPTP, show a similar profile of parkinsonism to that seen after the neurotoxin exposure to MPTP in young adult monkeys. The pattern of greater DA depletion in putamen than in caudate in aged monkeys is the same as in human Parkinson's disease and contrasts with the greater depletion in caudate seen after MPTP. Aged monkeys of this species reflect many facets of Parkinson's disease, but like older humans do not improve with standard dopamine replacement pharmacotherapies. PMID:21620883

Suspension of Mitotic Activity in Dentate Gyrus of the Hibernating Ground Squirrel

PubMed Central

Popov, Victor I.; Kraev, Igor V.; Ignat'ev, Dmitri A.; Stewart, Michael G.

2011-01-01

Neurogenesis occurs in the adult mammalian hippocampus, a region of the brain important for learning and memory. Hibernation in Siberian ground squirrels provides a natural model to study mitosis as the rapid fall in body temperature in 24 h (from 35-36°C to +4–6°C) permits accumulation of mitotic cells at different stages of the cell cycle. Histological methods used to study adult neurogenesis are limited largely to fixed tissue, and the mitotic state elucidated depends on the specific phase of mitosis at the time of day. However, using an immunohistochemical study of doublecortin (DCX) and BrdU-labelled neurons, we demonstrate that the dentate gyrus of the ground squirrel hippocampus contains a population of immature cells which appear to possess mitotic activity. Our data suggest that doublecortin-labelled immature cells exist in a mitotic state and may represent a renewable pool for generation of new neurons within the dentate gyrus. PMID:21773054

Gray squirrels reproduce in a 2-acre enclosure

Treesearch

H. Reed Sanderson; Larry A. Berry

1973-01-01

A 2-acre enclosure was built in a 40-year-old hardwood stand, and 5 to 19 gray squirrels (Sciurus carolinensis) were confined in it during 3 years. Reproductive behavior of the squirrels was the same at all population densities, but densities above 12 may have reduced productivity. For 10 to 12 squirrels, behavior was about normal and productivity...

Ames Research Center life sciences payload - Overview of results of a spaceflight of 24 rats and 2 monkeys

NASA Technical Reports Server (NTRS)

Callahan, P. X.; Schatte, C.; Grindeland, R. E.; Bowman, G.; Lencki, W. A.

1985-01-01

Engineering and biological data gathered with the research animal holding facilities (RAHFs) used on the Spacelab 3 mission are summarized. The animals totaled 24 rats and two squirrel monkeys. The RAHFs included biotelemetry, cameras and environmental monitoring equipment. The primary mission goal was engineering evaluation of the RAHFs and ancillary equipment. Tightly-fitted seals were found to be a necessity for keeping waste and food particles from contaminating the Spacelab equipment. All the rats returned with little muscle tone and suppressed immune systems. The monkeys displayed highly individual responses to spaceflight. Both species exhibited reduced abilities to maintain meticulously clean furs in weightlessness. Details of several physiological changes detected during post-flight autopsies are provided.

Hoarding patterns in the southern flying squirrel (Glaucomys volans)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clemmer, S.M.

1984-05-01

Southern flying squirrels, Glaucomys volans, were individually offered two size classes of pecans in a 1:1 ratio to establish preference. All but one squirrel preferred small pecans. As relative abundance of preferred food diminished to 0.10, squirrels switched preference. Absolute abundance of either food did not affect caching levels. A difficulty-of-retrieval experiment did not result in switching of preference. No effect of sex on hoarding was exhibited. There was an inverse correlation between individual storing effort and caching levels of the same squirrels tested as pairs, with individual non-storers showing increases in numbers of pecans stored. Animals that were activemore » storers as individuals showed decreases when paired. Total number stored did not decrease significantly when squirrels were offered previously marked pecans. When offered own-marked and other-marked pecans, squirrels did not discriminate. 43 references, 3 figures, 6 tables.« less

Different neural strategies for multimodal integration: comparison of two macaque monkey species.

PubMed

Sadeghi, Soroush G; Mitchell, Diana E; Cullen, Kathleen E

2009-05-01

The integration of neck proprioceptive and vestibular inputs underlies the generation of accurate postural and motor control. Recent studies have shown that central mechanisms underlying the integration of these sensory inputs differ across species. Notably, in rhesus monkey (Macaca mulata), an Old World monkey, neurons in the vestibular nuclei are insensitive to passive stimulation of neck proprioceptors. In contrast, in squirrel monkey, a New World monkey, stimulation produces robust modulation. This has led to the suggestion that there are differences in how sensory information is integrated during self-motion in Old versus New World monkeys. To test this hypothesis, we recorded from neurons in the vestibular nuclei of another species in the Macaca genus [i.e., M. fascicularis (cynomolgus monkey)]. Recordings were made from vestibular-only (VO) and position-vestibular-pause (PVP) neurons. The majority (53%) of neurons in both groups were sensitive to neck proprioceptive and vestibular stimulation during passive body-under-head and whole-body rotation, respectively. Furthermore, responses during passive rotations of the head-on-body were well predicted by the linear summation of vestibular and neck responses (which were typically antagonistic). During active head movement, the responses of VO and PVP neurons were further attenuated (relative to a model based on linear summation) for the duration of the active head movement or gaze shift, respectively. Taken together, our findings show that the brain's strategy for the central processing of sensory information can vary even within a single genus. We suggest that similar divergence may be observed in other areas in which multimodal integration occurs.

Different Neural Strategies for Multimodal Integration: Comparison of two Macaque Monkey Species

PubMed Central

Sadeghi, Soroush G.; Mitchell, Diana E.; Cullen, Kathleen E.

2012-01-01

The integration of neck proprioceptive and vestibular inputs underlies the generation of accurate postural and motor control. Recent studies have shown that central mechanisms underlying the integration of these sensory inputs differ across species. Notably, in rhesus monkey (macaca mulata), an Old World monkey, neurons in the vestibular nuclei are insensitive to passive stimulation of neck proprioceptors. In contrast, in squirrel monkey, a New World monkey, stimulation produces robust modulation. This has led to the suggestion that there are differences in how sensory information is integrated during self motion in old versus New World monkeys. To test this hypothesis, we recorded from neurons in the vestibular nuclei of another species in the macaca genus (i.e., macaca fascicularis (cynomolgus monkey)). Recordings were made from vestibular-only (VO) and position-vestibular-pause (PVP) neurons. The majority (53%) of neurons in both groups were sensitive to neck proprioceptive and vestibular stimulation during passive body-under-head and whole body rotation, respectively. Furthermore, responses during passive rotations of the head-on-body were well predicted by the linear summation of vestibular and neck responses (which were typically antagonistic). During active head movement, the responses of VO and PVP neurons were further attenuated (relative to a model based on linear summation) for the duration of the active head movement or gaze shift, respectively. Taken together, our findings show that the brain's strategy for the central processing of sensory information can vary even within a single genus. We suggest that similar divergence may be observed in other areas in which multimodal integration occurs. PMID:19283371

Spacelab 4: Primate experiment support hardware

NASA Astrophysics Data System (ADS)

Fusco, P. R.; Peyran, R. J.

1984-05-01

A squirrel monkey feeder and automatic urine collection system were designed to fly on the Spacelab 4 Shuttle Mission presently scheduled for January 1986. Prototypes of the feeder and urine collection systems were fabricated and extensively tested on squirrel monkeys at the National Aeronautics and Space Administration's (NASA) Ames Research Center (ARC). The feeder design minimizes impact on the monkey's limited space in the cage and features improved reliability and biocompatibility over previous systems. The urine collection system is the first flight qualified, automatic urine collection device for squirrel monkeys. Flight systems are currently being fabricated.

Spacelab 4: Primate experiment support hardware

NASA Technical Reports Server (NTRS)

Fusco, P. R.; Peyran, R. J.

1984-01-01

A squirrel monkey feeder and automatic urine collection system were designed to fly on the Spacelab 4 Shuttle Mission presently scheduled for January 1986. Prototypes of the feeder and urine collection systems were fabricated and extensively tested on squirrel monkeys at the National Aeronautics and Space Administration's (NASA) Ames Research Center (ARC). The feeder design minimizes impact on the monkey's limited space in the cage and features improved reliability and biocompatibility over previous systems. The urine collection system is the first flight qualified, automatic urine collection device for squirrel monkeys. Flight systems are currently being fabricated.

Horizontal vestibuloocular reflex evoked by high-acceleration rotations in the squirrel monkey. I. Normal responses

NASA Technical Reports Server (NTRS)

Minor, L. B.; Lasker, D. M.; Backous, D. D.; Hullar, T. E.; Shelhamer, M. J. (Principal Investigator)

1999-01-01

The horizontal angular vestibuloocular reflex (VOR) evoked by high-frequency, high-acceleration rotations was studied in five squirrel monkeys with intact vestibular function. The VOR evoked by steps of acceleration in darkness (3,000 degrees /s(2) reaching a velocity of 150 degrees /s) began after a latency of 7.3 +/- 1.5 ms (mean +/- SD). Gain of the reflex during the acceleration was 14.2 +/- 5.2% greater than that measured once the plateau head velocity had been reached. A polynomial regression was used to analyze the trajectory of the responses to steps of acceleration. A better representation of the data was obtained from a polynomial that included a cubic term in contrast to an exclusively linear fit. For sinusoidal rotations of 0.5-15 Hz with a peak velocity of 20 degrees /s, the VOR gain measured 0.83 +/- 0.06 and did not vary across frequencies or animals. The phase of these responses was close to compensatory except at 15 Hz where a lag of 5.0 +/- 0.9 degrees was noted. The VOR gain did not vary with head velocity at 0.5 Hz but increased with velocity for rotations at frequencies of >/=4 Hz (0. 85 +/- 0.04 at 4 Hz, 20 degrees /s; 1.01 +/- 0.05 at 100 degrees /s, P < 0.0001). No responses to these rotations were noted in two animals that had undergone bilateral labyrinthectomy indicating that inertia of the eye had a negligible effect for these stimuli. We developed a mathematical model of VOR dynamics to account for these findings. The inputs to the reflex come from linear and nonlinear pathways. The linear pathway is responsible for the constant gain across frequencies at peak head velocity of 20 degrees /s and also for the phase lag at higher frequencies being less than that expected based on the reflex delay. The frequency- and velocity-dependent nonlinearity in VOR gain is accounted for by the dynamics of the nonlinear pathway. A transfer function that increases the gain of this pathway with frequency and a term related to the third power of head

Precocious quantitative cognition in monkeys.

PubMed

Ferrigno, Stephen; Hughes, Kelly D; Cantlon, Jessica F

2016-02-01

Basic quantitative abilities are thought to have an innate basis in humans partly because the ability to discriminate quantities emerges early in child development. If humans and nonhuman primates share this developmentally primitive foundation of quantitative reasoning, then this ability should be present early in development across species and should emerge earlier in monkeys than in humans because monkeys mature faster than humans. We report that monkeys spontaneously make accurate quantity choices by 1 year of age in a task that human children begin to perform only at 2.5 to 3 years of age. Additionally, we report that the quantitative sensitivity of infant monkeys is equal to that of the adult animals in their group and that rates of learning do not differ between infant and adult animals. This novel evidence of precocious quantitative reasoning in infant monkeys suggests that human quantitative reasoning shares its early developing foundation with other primates. The data further suggest that early developing components of primate quantitative reasoning are constrained by maturational factors related to genetic development as opposed to learning experience alone.

Dopamine D3 and D2 Receptor Mechanisms in the Abuse-Related Behavioral Effects of Cocaine: Studies with Preferential Antagonists in Squirrel Monkeys

PubMed Central

Grundt, Peter; Cao, Jianjing; Platt, Donna M.; Newman, Amy Hauck; Spealman, Roger D.

2010-01-01

Dopamine (DA) D3 and D2 receptor mechanisms are implicated in cocaine's abuse-related behavioral effects, but the relative contribution of the two receptor subtypes is only partially characterized. This study investigated the role of D3 and D2 subtype mechanisms by determining the degree to which the D3-preferring antagonist PG01037 [N-{4-[4-(2,3-dichlorophenyl)-piperazin- 1-yl]-trans-but-2-enyl}-4-pyridine-2-yl-benzamide HCl] and the D2-preferring antagonist L-741626 [3-[4-(4-chlorophenyl)-4- hydroxypiperidin-1-yl]methyl-1H-indole] attenuated several behavioral effects of cocaine in squirrel monkeys. Quantitative observational studies established doses of each antagonist that did not produce untoward effects, which were used in subsequent comparisons. In addition, the ability of the D3-preferring agonist PD128907 [(R-(+)-trans-3,4a,10b-tetrahydro-4-propyl-2H,5H-[1]benzopyrano[4,3-b]-1,4-oxazin-9-ol)] and the D2-preferring agonist sumanirole [(R)-5,6-dihydro-5-(methylamino)-4H- imidazo[4,5,1-ij]quinolin-2(1H)-one(Z)-2-butenedioate] to reproduce cocaine's discriminative stimulus (DS) and priming effects were compared. In monkeys trained to discriminate cocaine from vehicle, both DA antagonists attenuated and both DA agonists partially reproduced cocaine's DS effects. PG01037 also selectively attenuated the cocaine-like DS effects of PD128907, whereas L-741626 attenuated the cocaine-like DS effects of both agonists. In self-administration studies, L-741626 nonselectively reduced cocaine- and food-maintained responding, whereas PG01037 was ineffective against either reinforcer. In studies involving reinstatement of extinguished cocaine seeking, both antagonists attenuated cocaine-induced reinstatement of responding, and both agonists induced at least partial reinstatement of cocaine seeking. L-741626 also attenuated sumanirole-induced, but not PD128907-induced, reinstatement of responding, whereas PG01037 was ineffective against either DA agonist. The results are

Aged monkeys as a partial model for Parkinson's disease.

PubMed

Hurley, P J; Elsworth, J D; Whittaker, M C; Roth, R H; Redmond, D E

2011-09-01

Parkinson's Disease (PD) and the natural aging process share a number of biochemical mechanisms, including reduced function of dopaminergic systems. The present study aims to determine the extent that motor and behavioral changes in aged monkeys resemble parkinsonism induced by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. The behavioral and physiological changes in PD are believed to result largely from selective depletion of dopamine in the nigrostriatal system. In the present study, ten aged female monkeys were compared with three groups: 9 untreated young adult female monkeys, 10 young adult male monkeys and 13 older male monkeys that had been exposed to MPTP. Trained observers, blind as to age and drug condition and without knowledge of the hypotheses, scored the monkeys using the Parkinson's factor score (Parkscore), which has been validated by a high correlation with post mortem striatal dopamine (DA) concentrations. The aged animals had higher scores on the Parkscore compared with the young adults, with most of its component behavioral items showing significance (tremor, Eating Problems, Delayed initiation of movement, and Poverty of Movement). L-Dopa and DA-agonists did not clearly reverse the principal measure of parkinsonism. DA concentrations post mortem were 63% lower in 3 aged monkeys in the ventral putamen compared with 4 young adults, with greater reductions in putamen than in caudate (45%). We conclude that aged monkeys, unexposed to MPTP, show a similar profile of parkinsonism to that seen after the neurotoxin exposure to MPTP in young adult monkeys. The pattern of greater DA depletion in putamen than in caudate in aged monkeys is the same as in human Parkinson's disease and contrasts with the greater depletion in caudate seen after MPTP. Aged monkeys of this species reflect many facets of Parkinson's disease, but like older humans do not improve with standard dopamine replacement pharmacotherapies. Copyright © 2011 Elsevier Inc

Interspecies radioimmunoassay for the major structural proteins of primate type-D retroviruses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colcher, D.; Teramoto, Y.A.; Schlom, J.

1977-12-01

A competition radioimmunoassay has been developed in which type-D retroviruses from three primate species compete. The assay utilizes the major structural protein (36,000 daltons) of the endogenous squirrel monkey retrovirus and antisera directed against the major structural protein (27,000 daltons) of the Mason-Pfizer monkey virus isolated from rhesus monkeys. Purified preparations of both viruses grown in heterologous cells, as well as extracts of heterologous cells infected with squirrel monkey retrovirus or Mason-Pfizer monkey virus, compete completely in the assay. Addition of an endogenous virus of the langur monkey also results in complete blocking. No blocking in the assay is observedmore » with type-C baboon viruses, woolly monkey virus, and gibbon virus. Various other type-C and type-B viruses also showed no reactivity. An interspecies assay has thus been developed that recognizes the type-D retroviruses from both Old World monkey (rhesus and langur) and New World monkey (squirrel) species.« less

Seasonal use of red-cockaded woodpecker cavities by southern flying squirrels.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loeb, Susan C; Ruth, Deanna L

2004-12-31

Loeb, Susan C., and Deanna L. Ruth. 2004. Seasonal use of red-cockaded woodpecker cavities by southern flying squirrels. In: Red-cockaded woodpecker; Road to Recovery. Proceedings of the 4th Red-cockaded woodpecker Symposium. Ralph Costa and Susan J. Daniels, eds. Savannah, Georgia. January, 2003. Chapter 8. Cavities, Cavity Trees, and Cavity Communities. Pp 501-502. Abstract: Southern flying squirrels can significantly impact red-cockaded woodpecker reproductive success (Laves and Loeb 1999). Thus exclusion or removal of flying squirrels from red-cockaded woodpecker cavities and clusters may be warranted in small woodpecker populations (U.S. Fish and Wildlife Service 2003). However, development of effective and efficient protocolsmore » for southern flying squirrel control requires an understanding of the seasonal dynamics of southern flying squirrel cavity use. Most studies of southern flying squirrel use of red-cockaded woodpecker cavities have been conducted during spring (e.g., Harlow and Lennartz 1983, Rudolph et al. 1990a, Loeb 1993) and no studies have examined the effects of long term flying squirrel control on subsequent cavity use. The objectives of this study were to determine: (1) whether flying squirrel use of red-cockaded woodpecker cavities varies with season or cavity type, and (2) the long term effect of continuous squirrel removal.« less

Parasites of the Abert's squirrel (Sciurus aberti) and red squirrel (Tamiasciurus hudsonicus) of New Mexico.

PubMed

Patrick, M J; Wilson, W D

1995-04-01

Between 1989 and 1991, 29 Abert squirrels (Sciurus aberti) and 45 red squirrels (Tamiasciurus hudsonicus) were collected in New Mexico and examined for parasites. Of 29 S. aberti examined, 86.2% (25/29) were infected with at least 1 parasite species. Helminths were found in 62.1% (18/29) of S. aberti; 37.9% (11/29) were infected with fleas and 37.9% (11/29) with the coccidian Eimeria tamiasciuri. Among T. hudsonicus, 82.5% of the squirrels examined were infected with at least 1 parasite. Helminths were found in 57.8% (26/45) of T. hudsonicus; 22.2% (10/45) were infected with fleas and 26.7% (12/45) with Eimeria tamiasciuri. Citellinema quadrivittati was found in squirrels of both species; 55.2% (16/29) of S. aberti were infected, with 57.8% (26/45) of T. hudsonicus carrying the parasite. Enterobius sciuri was only found in S. aberti with 17.2% (5/29) carrying the infection. One cestode, Hymenolepis sp., was found only in T. hudsonicus with 6.7% (3/45) carrying the infection. Four species of flea were found on squirrels of both species. Ceratophyllus vison was found on 6.9% (2/29) of S. aberti and 6.7% (3/45) of T. hudsonicus examined. Opisodasys robustus was found on 6.9% (2/29) of S. aberti and 8.8% (4/45) of T. hudsonicus examined. Orchopeas caedens caedens was found on 3.4% (1/29) of S. aberti and 6.7% (3/45) of T. hudsonicus examined. Orchopeas neotomae was found on 10.3% (3/29) of S. aberti and 6.7% (3/45) of T. hudsonicus examined. Two species of flea were only found on T. hudsonicus; Orchopeas leucopus was found on 2.2% (1/45) and Oropsylla idahoensis was found on 2.2% (1/45) of the T. hudsonicus examined.(ABSTRACT TRUNCATED AT 250 WORDS)

Nervus terminalis, olfactory nerve, and optic nerve representation of luteinizing hormone-releasing hormone in primates.

PubMed

Witkin, J W

1987-01-01

The luteinizing hormone-releasing hormone (LHRH) system was examined immunocytochemically in olfactory bulbs of adult monkeys, including two New World species (squirrel monkey, Saimiri sciureus and owl monkey, Aotus trivirgatus) and one Old World species (cynomolgus macaque, Macaca fasciculata), and in the brain and nasal region of a fetal rhesus macaque Macaca mulatta. LHRH neurons and fibers were found sparsely distributed in the olfactory bulbs in all adult monkeys. There was more LHRH in the accessory olfactory bulb (which is absent in Old World monkeys). In the fetal macaque there was a rich distribution of LHRH neurons and fibers along the pathway of the nervus terminalis, anterior and ventral to the olfactory bulb, and in the nasal septum, with fibers branching into the olfactory epithelium. In addition, there were LHRH neurons and fibers in the optic nerve.

Ectoparasites of a population of urban gray squirrels in northern Florida.

PubMed

Wilson, N A; Telford, S R; Forrester, D J

1991-05-01

Ectoparasites infesting a population of urban gray squirrels (Sciurus carolinensis Gmelin) in northern Florida were collected monthly during 1974. Eleven species were identified: one flea (Orchopeas howardi (Baker], three suckling lice (Enderleinellus longiceps Kellogg & Ferris, Hoplopleura sciuricola Ferris, and Neohaematopinus sciuri Jancke), one tick (Dermacentor variabilis Say), two mesostigmatid (gamasid) mites (Androlaelaps casalis (Berlese) and A. fahrenholzi (Berlese], and four chiggers (Eutrombicula alfreddugesi (Oudemans), E. splendens (Ewing), Leptotrombidium peromysci Vercammen-Grandjean & Langston, and Parasecia gurneyi (Ewing]. The flea and three suckling lice represent core species of ectoparasites for the gray squirrel; the remainder are probably satellite species. Only E. longiceps varied significantly in prevalence or intensity of infestation among host age groups; subadult squirrels had higher intensities than adults. Peak prevalence of O. howardi occurred in January and attained maximum intensity in March, whereas both prevalance and intensity were minimum in August. Prevalence of H. sciuricola was maximum in November and remained at similar levels through June. It then declined significantly to its minimum in September-October. Intensity of infestation, however, was greatest in August, September, and January. Maximum prevalence of N. sciuri occurred from January to March and was minimum in September; intensity of infestation reached maxima in January, June, and August.

Seasonal and among-site variation in the occurrence and abundance of fleas on California ground squirrels (Otospermophilus beecheyi).

PubMed

Hubbart, Jason A; Jachowski, David S; Eads, David A

2011-06-01

An improved understanding of the ecology of fleas on California ground squirrels, Otospermophilus beecheyi, is warranted given the role of fleas in the transmission, and perhaps persistence, of the plague-causing bacterium Yersinia pestis. We sampled O. beecheyi on a seasonal basis from three study sites, each representing a different land use type (preserve, pasture, and agriculture) in the San Joaquin Valley, CA. Overall, the abundance of fleas on squirrels was greatest in spring at the preserve site, in summer at the agriculture and pasture sites, and in winter at the pasture site. Hoplopsyllus anomalus, the species most frequently found on squirrels, was most abundant in spring at the preserve site and in summer at the agriculture and pasture sites. Oropsylla montana was most abundant in winter at the pasture site and on adult squirrels. Echidnophaga gallinacea was most abundant in fall on juvenile squirrels at the preserve site. All three flea species we encountered are known to be potential vectors of Y. pestis. Future efforts to predict flea species occurrence and abundance (and plague risk) at sites of concern should consider seasonal microclimatic conditions and the potential influence of human land use practices. © 2011 The Society for Vector Ecology.

Physiological identification of morphologically distinct afferent classes innervating the cristae ampullares of the squirrel monkey

NASA Technical Reports Server (NTRS)

Lysakowski, A.; Minor, L. B.; Fernandez, C.; Goldberg, J. M.

1995-01-01

1. Semicircular-canal afferents in the squirrel monkey were characterized by their resting discharge, discharge regularity, sensitivity to galvanic currents delivered to the ear (beta *), the gain (g2Hz), and phase lead (phi 2Hz) of their response to 2-Hz sinusoidal head rotations, and their antidromic conduction velocity. Discharge regularity was measured by a normalized coefficient of variation (CV*); the higher the CV*, the more irregular the discharge. g2Hz and phi 2Hz were expressed relative to angular head velocity. 2. These physiological measures were used in an attempt to discern the discharge properties of the three morphological classes of afferents innervating the crista. Presumed bouton (B) fibers were identified as slowly conducting afferents. Presumed calyx (C) fibers were recognized by their irregular discharge and low rotational gains. The remaining fibers were considered to be dimorphic (D) units. Single letters (B, C, and D) are used to emphasize that the classification is based on circumstantial evidence and may be wrong for individual fibers. Of the 125 identified fibers, 13 (10%) were B units, 36 (29%) were C units, and 76 (61%) were D units. 3. B units were regularly discharging D units ranged from regularly to irregularly discharging. C units were the most irregularly discharging afferents encountered. The mean resting discharge for the entire sample was 74 spikes/s. Resting rates were similar for regularly discharging B and D units and higher than those for irregularly discharging C and D units. 4. Except for their lower conduction velocities, the discharge properties of B units are indistinguishable from those of regularly discharging D units. Many of the discharge properties of B and D units vary with discharge regularity. There is a strong, positive relation when beta *, g2Hz, or phi 2Hz is plotted against CV*. For beta * or phi 2Hz, C units conform to the relation for B and D units. In contrast, values of g2Hz for C units are three to

Squirrels cannot live by truffles alone: a closer look at a northwest keystone complex.

Treesearch

Sally Duncan

2004-01-01

Tree squirrels in the Pacific Northwest are part of a keystone complex that includes ectomycorrhizal fungi, Douglas-fir, and spotted owls. All three squirrel species—the northern flying squirrel, the Douglas' squirrel, and the Townsend’s squirrel—consume truffles produced by fungal partners of important tree species. The squirrels then spread the spores of these...

Role of the vestibular end organs in experimental motion sickness - A primate model

NASA Technical Reports Server (NTRS)

Igarashi, Makoto

1990-01-01

Experimental studies of the role of vestibular end organs in motion sickness experienced by squirrel monkeys are reviewed. The first experiments in motion-sickness-susceptible squirrel monkeys were performed under a free-moving condition with horizontal rotation and vertical oscillation. In the following experiments, the vestibular-visual conflict in the pitch plane was given to the chair-restrained (upright position) squirrel monkeys. Results of this study showed that the existence of otolith afferents, which continually signal the directional change of gravity and linear acceleration vectors, was necessary for the elicitation of emesis by the sensory conflict in pitch.

Yellow-bellied marmot and golden-mantled ground squirrel responses to heterospecific alarm calls

PubMed

Shriner

1998-03-01

When two species have predators in common, animals might be able to obtain important information about predation risk from the alarm calls produced by the other species. The behavioural responses of adult yellow-bellied marmots, Marmota flaviventris, and golden-mantled ground squirrels, Spermophilus lateralis, to conspecific and heterospecific alarm calls were studied to determine whether interspecific call recognition occurs in sympatric species that rarely interact. In a crossed design, marmot and squirrel alarm calls were broadcast to individuals of both species, using the song of a sympatric bird as a control. Individuals of both species responded similarly to conspecific and heterospecific anti-predator calls, and distinguished both types of alarms from the bird song. These results indicate that both marmots and squirrels recognized not only their own species' anti-predator vocalizations, but also the alarm calls of another species, and that these vocalizations were discriminated from an equally loud non-threatening sound. These findings suggest that researchers ought to think broadly when considering the sources of information available to animals in their natural environment. Copyright 1998 The Association for the Study of Animal Behaviour Copyright 1998 The Association for the Study of Animal Behaviour.

Cone pigment polymorphism in New World monkeys: are all pigments created equal?

PubMed

Rowe, Mickey P; Jacobs, Gerald H

2004-01-01

Most platyrrhine monkeys have a triallelic M/L opsin gene polymorphism that underlies significant individual variations in color vision. A survey of the frequencies of these polymorphic genes suggests that the three alleles occur with equal frequency among squirrel monkeys (subfamily Cebinae), but are not equally frequent in a number of species from the subfamily Callitrichinae. This departure from equal frequency in the Callitrichids should slightly increase the ratio of dichromats to trichromats in the population and significantly alter the relative representation of the three possible dichromatic and trichromatic phenotypes. A particular feature of the inequality is that it leads to a relative increase in the number of trichromats whose M/L pigments have the largest possible spectral separation. To assess whether these trichromatic phenotypes are equally well equipped to make relevant visual discriminations, psychophysical experiments were run on human observers. A technique involving the functional substitution of photopigments was used to simulate the discrimination between fruits among a background of leaves. The goal of the simulation was to reproduce in the cones of human observers excitations equivalent to those produced in monkey cones as the animals view fruit. Three different viewing conditions were examined involving variations in the relative luminances of fruit and leaves and the spectrum of the illuminant. In all cases, performance was best for simulated trichromacies including M/L pigments with the largest spectral separation. Thus, the inequality of opsin gene frequency in Callitrichid monkeys may reflect adaptive pressures.

The occurrence of hepatozoon in the gray squirrel (Sciurus carolinensis)

USGS Publications Warehouse

Herman, C.M.; Price, D.L.

1955-01-01

Hepatozoon sciuri (Coles, 1914) is reported from gray squirrels (Sciurus carolinensis) in Washington, D.C. and Maryland. Blood smears stained with Giemsa's stain revealed a parasitemia in 16 to 71% of the squirrels examined. A technique for laking the red cells and concentrating the white cells in blood samples demonstrated this protozoon to be present in every squirrel so tested.

Monitoring interactions between red-cockaded woodpeckers and southern flying squirrels.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Risch, Thomas S; Loeb, Susan C

2004-12-31

Risch, Thomas S., and Susan C. Loeb. 2004. Monitoring interactions between red-cockaded woodpeckers and southern flying squirrels. In: Red-cockaded woodpecker; Road to Recovery. Proceedings of the 4th Red-cockaded woodpecker Symposium. Ralph Costa and Susan J. Daniels, eds. Savannah, Georgia. January, 2003. Chapter 8. Cavities, Cavity Trees, and Cavity Communities. Pp 504-505. Abstract: Although several studies have suggested that southern flying squirrels (Glaucomys volans) may have a significant negative impact on red-cockades woodpeckers (Picoides borealsi) (Loeb and Hooper 1997, Laves and Loeb 1999), the nature of the interactions between the species remains unclear. Particularly lacking are data that address if southernmore » flying squirrels directly usurp red-cockaded woodpecker s from cavities, or simply occupy cavities previously abandoned by red-cockaded woodpeckers. Ridley et al. (1997) observed the displacement of a red-cockaded woodpecker by a southern flying squirrel that was released after being captured. Observations of nocturnal displacements of red-cockaded woodpeckers by flying squirrels, however, are lacking. Due to the difficulty of observing interspecific interactions, determining the mechanisims by which flying squirrels impact red-cockaded woodpeckers is problematic.« less

Response of northern flying squirrels to supplementary dens.

Treesearch

A.B. Carey

2002-01-01

The northern flying squirrel (Glaucomys sabrinus) is a keystone species in Pacific Northwest conifer forests, consuming and disseminating spores of ectomycorrhizal fungi essential to Pinaceae and preyed upon by different vertebrate predators. Increasing the numbers of flying squirrels has been suggested as part of a strategy to increase the...

Ground Squirrel Shooting and Potential Lead Exposure in Breeding Avian Scavengers

PubMed Central

Eagles-Smith, Collin A.; Wagner, Mason T.

2016-01-01

Recreational ground squirrel shooting is a popular activity throughout the western United States and serves as a tool for managing ground squirrel populations in agricultural regions. Belding’s ground squirrels (Spermophilus beldingi) are routinely shot in California, Nevada, and Oregon across habitats that overlap with breeding avian scavengers. Ground squirrels shot with lead (Pb)-based bullets may pose a risk to avian scavengers if they consume carcasses containing Pb fragments. To assess the potential risk to breeding avian scavengers we developed a model to estimate the number, mass, and distribution of Pb fragments in shot ground squirrels using radiographic images. Eighty percent of shot carcasses contained detectible Pb fragments with an average of 38.6 mg of Pb fragments. Seven percent of all carcasses contained Pb fragment masses exceeding a lethal dose for a model raptor nestling (e.g. American kestrel Falco sparverius). Bullet type did not influence the number of fragments in shot ground squirrels, but did influence the mass of fragments retained. Belding’s ground squirrels shot with .17 Super Mag and unknown ammunition types contained over 28 and 17 times more mass of Pb fragments than those shot with .22 solid and .22 hollow point bullets, respectively. Ground squirrel body mass was positively correlated with both the number and mass of Pb fragments in carcasses, increasing on average by 76% and 56% respectively across the range of carcass masses. Although the mass of Pb retained in ground squirrel carcasses was small relative to the original bullet mass, avian scavenger nestlings that frequently consume shot ground squirrels may be at risk for Pb-induced effects (e.g., physiology, growth, or survival). Using modeling efforts we found that if nestling golden eagles (Aquila chrysaetos), red-tailed hawks (Buteo jamaicensis), and Swainson’s hawks (B. swainsoni) consumed shot ground squirrels proportionately to the nestling’s mass, energy needs

Ground squirrel shooting and potential lead exposure in breeding avian scavengers

USGS Publications Warehouse

Herring, Garth; Eagles-Smith, Collin A.; Wagner, Mason T.

2016-01-01

Recreational ground squirrel shooting is a popular activity throughout the western United States and serves as a tool for managing ground squirrel populations in agricultural regions. Belding’s ground squirrels (Spermophilus beldingi) are routinely shot in California, Nevada, and Oregon across habitats that overlap with breeding avian scavengers. Ground squirrels shot with lead (Pb)-based bullets may pose a risk to avian scavengers if they consume carcasses containing Pb fragments. To assess the potential risk to breeding avian scavengers we developed a model to estimate the number, mass, and distribution of Pb fragments in shot ground squirrels using radiographic images. Eighty percent of shot carcasses contained detectible Pb fragments with an average of 38.6 mg of Pb fragments. Seven percent of all carcasses contained Pb fragment masses exceeding a lethal dose for a model raptor nestling (e.g. American kestrel Falco sparverius). Bullet type did not influence the number of fragments in shot ground squirrels, but did influence the mass of fragments retained. Belding’s ground squirrels shot with .17 Super Mag and unknown ammunition types contained over 28 and 17 times more mass of Pb fragments than those shot with .22 solid and .22 hollow point bullets, respectively. Ground squirrel body mass was positively correlated with both the number and mass of Pb fragments in carcasses, increasing on average by 76% and 56% respectively across the range of carcass masses. Although the mass of Pb retained in ground squirrel carcasses was small relative to the original bullet mass, avian scavenger nestlings that frequently consume shot ground squirrels may be at risk for Pb-induced effects (e.g., physiology, growth, or survival). Using modeling efforts we found that if nestling golden eagles (Aquila chrysaetos), red-tailed hawks (Buteo jamaicensis), and Swainson’s hawks (B. swainsoni) consumed shot ground squirrels proportionately to the nestling’s mass, energy needs

Influence of habitat on behavior of Towndsend's ground squirrels (Spermophilus townsendii)

USGS Publications Warehouse

Sharpe, Peter B.; Van Horne, Beatrice

1998-01-01

Trade-offs between foraging and predator avoidance may affect an animal's survival and reproduction. These trade-offs may be influenced by differences in vegetative cover, especially if foraging profitability and predation risk differ among habitats. We examined above-ground activity of Townsend's ground squirrels (Spermophilus townsendii) in four habitats in the Snake River Birds of Prey National Conservation Area in southwestern Idaho to determine if behavior of ground squirrels varied among habitats, and we assessed factors that might affect perceived predation risk (i. e. predator detectability, predation pressure, population density). The proportion of time spent in vigilance by ground squirrels in winterfat (Krascheninnikovia lanata) and mosaic habitats of winterfat-sagebrush (Artemisia tridentata) was more than twice that of ground squirrels in burned and unburned sagebrush habitats. We found no evidence for the 'many-eyes' hypothesis as an explanation for differences in vigilance among habitats. Instead, environmental heterogeneity, especially vegetation structure, likely influenced activity budgets of ground squirrels. Differences in vigilance may have been caused by differences in predator detectability and refuge availability, because ground squirrels in the winterfat and mosaic habitats also spent more time in upright vigilant postures than ground squirrels in burned-sagebrush or sagebrush habitats. Such postures may enhance predator detection in low-growing winterfat.

Molecular Prerequisites for Diminished Cold Sensitivity in Ground Squirrels and Hamsters.

PubMed

Matos-Cruz, Vanessa; Schneider, Eve R; Mastrotto, Marco; Merriman, Dana K; Bagriantsev, Sviatoslav N; Gracheva, Elena O

2017-12-19

Thirteen-lined ground squirrels and Syrian hamsters are known for their ability to withstand cold during hibernation. We found that hibernators exhibit cold tolerance even in the active state. Imaging and electrophysiology of squirrel somatosensory neurons reveal a decrease in cold sensitivity of TRPM8-expressing cells. Characterization of squirrel and hamster TRPM8 showed that the channels are chemically activated but exhibit poor activation by cold. Cold sensitivity can be re-introduced into squirrel and hamster TRPM8 by transferring the transmembrane domain from the cold sensitive rat ortholog. The same can be achieved in squirrel TRPM8 by mutating only six amino acids. Reciprocal mutations suppress cold sensitivity of the rat ortholog, supporting functional significance of these residues. Our results suggest that ground squirrels and hamsters exhibit reduced cold sensitivity, partially due to modifications in the transmembrane domain of TRPM8. Our study reveals molecular adaptations that accompany cold tolerance in two species of mammalian hibernators. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Horizontal vestibuloocular reflex evoked by high-acceleration rotations in the squirrel monkey. III. Responses after labyrinthectomy

NASA Technical Reports Server (NTRS)

Lasker, D. M.; Hullar, T. E.; Minor, L. B.; Shelhamer, M. J. (Principal Investigator)

2000-01-01

The horizontal angular vestibuloocular reflex (VOR) evoked by high-frequency, high-acceleration rotations was studied in four squirrel monkeys after unilateral labyrinthectomy. Spontaneous nystagmus was measured at the beginning and end of each testing session. During the period that animals were kept in darkness (4 days), the nystagmus at each of these times measured approximately 20 degrees /s. Within 18-24 h after return to the light, the nystagmus (measured in darkness) decreased to 2.8 +/- 1.5 degrees /s (mean +/- SD) when recorded at the beginning but was 20.3 +/- 3.9 degrees /s at the end of the testing session. The latency of the VOR measured from responses to steps of acceleration (3,000 degrees /s(2) reaching a velocity of 150 degrees /s) was 8.4 +/- 0.3 ms for responses to ipsilesional rotations and 7.7 +/- 0.4 ms for contralesional rotations. During the period that animals were kept in darkness after the labyrinthectomy, the gain of the VOR measured during the steps of acceleration was 0.67 +/- 0.12 for contralesional rotations and 0.39 +/- 0.04 for ipsilesional rotations. Within 18-24 h after return to light, the VOR gain for contralesional rotations increased to 0.87 +/- 0.08, whereas there was only a slight increase for ipsilesional rotations to 0.41 +/- 0. 06. A symmetrical increase in the gain measured at the plateau of head velocity was noted after the animals were returned to light. The VOR evoked by sinusoidal rotations of 2-15 Hz, +/-20 degrees /s, showed a better recovery of gain at lower (2-4 Hz) than at higher (6-15 Hz) frequencies. At 0.5 Hz, gain decreased symmetrically when the peak amplitude was increased from 20 to 100 degrees /s. At 10 Hz, gain was decreased for ipsilesional half-cycles and increased for contralesional half-cycles when velocity was raised from 20 to 50 degrees /s. A model incorporating linear and nonlinear pathways was used to simulate the data. Selective increases in the gain for the linear pathway accounted for the

Response Properties of Cochlear Nucleus Neurons in Monkeys

PubMed Central

Roth, G. Linn; Recio, A.

2009-01-01

Much of what is known about how the cochlear nuclei participate in mammalian hearing comes from studies of non-primate mammalian species. To determine to what extent the cochlear nuclei of primates resemble those of other mammalian orders, we have recorded responses to sound in three primate species: marmosets, Cynomolgus macaques, and squirrel monkeys. These recordings show that the same types of temporal firing patterns are found in primates that have been described in other mammals. Responses to tones of neurons in the ventral cochlear nucleus have similar tuning, latencies, post-stimulus time and interspike interval histograms as those recorded in non-primate cochlear nucleus neurons. In the dorsal cochlear nucleus, too, responses were similar. From these results it is evident that insights gained from non-primate studies can be applied to the peripheral auditory system of primates. PMID:19531377

The topography of primate retina: a study of the human, bushbaby, and new- and old-world monkeys.

PubMed

Stone, J; Johnston, E

1981-02-20

The distribution of ganglion cells has been studied in the retinas of four primates: the prosimian bushbaby, the New-World squirrel monkey, the Old-World crab-eating cynamolgous monkey, and the human. The sizes of ganglion cell somas were also measured at a number of retinal locations and compared with similar measurements in the cat retina to test for the presence in primates of retinal specializations such as the visual streak, and for gradients in retinal structure, such as that between temporal and nasal retina. In all four primates, ganglion cell somas in peripheral retina ranged considerably in diameter (6-16 micrometer in the bushbaby, 8-22 micrometer in the squirrel monkey, 8-23 micrometer in the cynamolgous monkey, 8-26 micrometer in the human). It seems likely that the strong physiological correlates of soma size which have been described among cat retinal ganglion cells and among the relay cells of the macaque lateral geniculate nucleus are generally present in primates. In all four primates, evidence was also obtained of a visual streak specialization; the isodensity lines in ganglion cell density maps were horizontally elongated, and small-bodied ganglion cells were relatively more common in the region of the proposed streak than in other areas of peripheral retina. However, the visual streak seems less well developed than in the cat; among the four primate species examined it was best developed in the bushbaby, at least as assessed by the shape of the isodensity lines. All four primates showed a clear foveal specialization, but this feature seemed least developed in the bushbaby. At the fovea, ganglion cells are smaller in soma size than in peripheral retina; they also seemed more uniform in size, although some distinctly larger cells persist in the human and bushbaby. Soma size measurements also provided evidence of a difference between nasal and temporal areas of peripheral retina comparable to that reported for the cat and other species. Thus the

Receptive-field subfields of V2 neurons in macaque monkeys are adult-like near birth.

PubMed

Zhang, Bin; Tao, Xiaofeng; Shen, Guofu; Smith, Earl L; Ohzawa, Izumi; Chino, Yuzo M

2013-02-06

Infant primates can discriminate texture-defined form despite their relatively low visual acuity. The neuronal mechanisms underlying this remarkable visual capacity of infants have not been studied in nonhuman primates. Since many V2 neurons in adult monkeys can extract the local features in complex stimuli that are required for form vision, we used two-dimensional dynamic noise stimuli and local spectral reverse correlation to measure whether the spatial map of receptive-field subfields in individual V2 neurons is sufficiently mature near birth to capture local features. As in adults, most V2 neurons in 4-week-old monkeys showed a relatively high degree of homogeneity in the spatial matrix of facilitatory subfields. However, ∼25% of V2 neurons had the subfield map where the neighboring facilitatory subfields substantially differed in their preferred orientations and spatial frequencies. Over 80% of V2 neurons in both infants and adults had "tuned" suppressive profiles in their subfield maps that could alter the tuning properties of facilitatory profiles. The differences in the preferred orientations between facilitatory and suppressive profiles were relatively large but extended over a broad range. Response immaturities in infants were mild; the overall strength of facilitatory subfield responses was lower than that in adults, and the optimal correlation delay ("latency") was longer in 4-week-old infants. These results suggest that as early as 4 weeks of age, the spatial receptive-field structure of V2 neurons is as complex as in adults and the ability of V2 neurons to compare local features of neighboring stimulus elements is nearly adult like.

Early Wisconsinan (MIS 4) Arctic ground squirrel middens and a squirrel-eye-view of the mammoth-steppe

NASA Astrophysics Data System (ADS)

Zazula, Grant D.; Froese, Duane G.; Elias, Scott A.; Kuzmina, Svetlana; Mathewes, Rolf W.

2011-08-01

Fossil arctic ground squirrel ( Spermophilus parryii) middens were recovered from ice-rich loess sediments in association with Sheep Creek-Klondike and Dominion Creek tephras (ca 80 ka) exposed in west-central Yukon. These middens provide plant and insect macrofossil evidence for a steppe-tundra ecosystem during the Early Wisconsinan (MIS 4) glacial interval. Midden plant and insect macrofossil data are compared with those previously published for Late Wisconsinan middens dating to ˜25-29 14C ka BP (MIS 3/2) from the region. Although multivariate statistical comparisons suggest differences between the relative abundances of plant macrofossils, the co-occurrence of steppe-tundra plants and insects (e.g., Elymus trachycaulus, Kobresia myosuroides, Artemisia frigida, Phlox hoodii, Connatichela artemisiae) provides evidence for successive reestablishment of the zonal steppe-tundra habitats during cold stages of the Late Pleistocene. Arctic ground squirrels were well adapted to the cold, arid climates, steppe-tundra vegetation and well-drained loessal soils that characterize cold stages of Late Pleistocene Beringia. These glacial conditions enabled arctic ground squirrel populations to expand their range to the interior regions of Alaska and Yukon, including the Klondike, where they are absent today. Arctic ground squirrels have endured numerous Quaternary climate oscillations by retracting populations to disjunct "interglacial refugia" during warm interglacial periods (e.g., south-facing steppe slopes, well-drained arctic and alpine tundra areas) and expanding their distribution across the mammoth-steppe biome during cold, arid glacial intervals.

Socialization of adult owl monkeys (Aotus sp.) in Captivity.

PubMed

Williams, Lawrence E; Coke, C S; Weed, J L

2017-01-01

Social housing has often been recommended as one-way to address the psychological well-being of captive non-human primates. Published reports have examined methods to socialize compatible animals by forming pairs or groups. Successful socialization rates vary depending on the species, gender, and environment. This study presents a retrospective look at pairing attempts in two species of owl monkeys, Aotus nancymaae and A. azarae, which live in monogamous pairs in the wild. The results of 477 pairing attempt conducted with captive, laboratory housed owl monkeys and 61 hr of behavioral observations are reported here. The greatest success pairing these owl monkeys occurred with opposite sex pairs, with an 82% success rate. Opposite sex pairs were more successful when females were older than males. Female-female pairs were more successful than male-male (MM) pairs (62% vs 40%). Successful pairs stayed together between 3 and 7 years before the animals were separated due to social incompatibility. Vigilance, eating, and sleeping during introductions significantly predicted success, as did the performance of the same behavior in both animals. The results of this analysis show that it is possible to give captive owl monkeys a social alternative even if species appropriate social partners (i.e., opposite sex partners) are not available. The focus of this report is a description of one potential way to enhance the welfare of a specific new world primate, the owl monkey, under laboratory conditions. More important is how the species typical social structure of owl monkeys in nature affects the captive management of this genus. Am. J. Primatol. 79:e22521, 2017. © 2015 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Attenuation of behavioral effects of cocaine by the Metabotropic Glutamate Receptor 5 Antagonist 2-Methyl-6-(phenylethynyl)-pyridine in squirrel monkeys: comparison with dizocilpine.

PubMed

Lee, Buyean; Platt, Donna M; Rowlett, James K; Adewale, Adepero S; Spealman, Roger D

2005-03-01

Growing evidence suggests a role for metabotropic glutamate receptors (mGluRs) in the behavioral effects of cocaine related to its abuse. The mGluR5 subtype, in particular, has come under scrutiny due to its distribution in brain regions associated with drug addiction. This study investigated interactions between the selective mGluR5 antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP) and cocaine in squirrel monkeys whose lever-pressing behavior was 1) maintained under a second-order schedule of cocaine self-administration, 2) extinguished and then reinstated by cocaine priming, and 3) controlled by the discriminative stimulus (DS) effects of cocaine. Additional studies determined the effects of MPEP on unconditioned behaviors, coordination, and muscle resistance. In each experiment, the effects of MPEP were compared with those of the N-methyl-d-aspartate antagonist dizocilpine. MPEP attenuated cocaine self-administration, cocaine-induced reinstatement of drug seeking, and the DS effects of cocaine at doses that did not markedly impair motor function or operant behavior in the context of drug discrimination. Dizocilpine also attenuated cocaine self-administration, but it did not significantly alter cocaine-induced reinstatement of drug seeking, and it enhanced rather than attenuated the DS effects of cocaine. The findings point to a significant contribution of mGluR5 mechanisms in the behavioral effects of cocaine related to its abuse and suggest that MPEP has properties of a functional cocaine antagonist, which are not secondary to antagonism at NMDA receptors. The contrasting interactions of MPEP and dizocilpine with cocaine imply that glutamate acting through different metabotropic and ionotropic receptors may modulate the behavioral effects of cocaine in qualitatively different ways.

Metabotropic glutamate receptor 5 shows different patterns of localization within the parallel visual pathways in macaque and squirrel monkeys.

PubMed

Shostak, Yuri; Wenger, Ashley; Mavity-Hudson, Julia; Casagrande, Vivien A

2014-09-24

Glutamate is used as an excitatory neurotransmitter by the koniocellular (K), magnocellular (M), and parvocellular (P) pathways to transfer signals from the primate lateral geniculate nucleus (LGN) to primary visual cortex (V1). Glutamate acts through both fast ionotropic receptors, which appear to carry the main sensory message, and slower, modulatory metabotropic receptors (mGluRs). In this study, we asked whether mGluR5 relates in distinct ways to the K, M, and P LGN axons in V1. To answer this question, we used light microscopic immunocytochemistry and preembedding electron microscopic immunogold labeling to determine the localization of mGluR5 within the layers of V1 in relation to the K, M, and P pathways in macaque and squirrel monkeys. These pathways were labeled separately via wheat germ agglutinin-horseradish peroxidase (WGA-HRP) injections targeting the LGN layers. mGluR5 is of interest because it: 1) has been shown to be expressed in the thalamic input layers; 2) appears to be responsible for some types of oscillatory firing, which could be important in the binding of visual features; and 3) has been associated with a number of sensory-motor gating-related pathologies, including schizophrenia and autism. Our results demonstrated the presence of mGluR5 in the neuropil of all V1 layers. This protein was lowest in IVCα (M input) and the infragranular layers. In layer IVC, mGluR5 also was found postsynaptic to about 30% of labeled axons, but the distribution was uneven, such that postsynaptic mGluR5 label tended to occur opposite smaller (presumed P), and not larger (presumed M) axon terminals. Only in the K pathway in layer IIIB, however, was mGluR5 always found in the axon terminals themselves. The presence of mGluR5 in K axons and not in M and P axons, and the presence of mGluR5 postsynaptic mainly to smaller P and not larger M axons suggest that the response to the release of glutamate is modulated in distinct ways within and between the parallel

Demography of northern flying squirrels informs ecosystem management of western interior forests.

Treesearch

John F. Lehmkuhl; Keith D. Kistler; James S. Begley; John. Boulanger

2006-01-01

We studied northern flying squirrel (Glaucomys sabrinus) demography in the eastern Washington Cascade Range to test hypotheses about regional and local abundance patterns and to inform managers of the possible effects of fire and fuels management on flying squirrels. We quantified habitat characteristics and squirrel density, population trends, and...

Texas ratsnake predation on southern flying squirrels in red-cockaded woodpecker cavities

Treesearch

D. Craig Rudolph; Richard R. Schaefer; Josh B. Pierce; Dan Saenz; Richard N. Conner

2009-01-01

Elaphe spp. (ratsnakes) are frequent predators on cavity-nesting birds and other vertebrates, including Glaucomys volans (Southern Flying Squirrels). They are known predators of Picoides borealis (Red-cockaded Woodpeckers), especially during the nestling phase. Picoides borealis cavities are frequently occupied by Southern Flying Squirrels, often several squirrels per...

Dens of northern flying squirrels in the Pacific Northwest.

Treesearch

A.B. Carey; T.M. Wilson; C.C. Maguire; B.L. Biswell

1997-01-01

Silvicultural prescriptions to enhance northern flying squirrel (Glaucoinys sabrinus) habitat have been suggested as an aid for recovery of the threatened northern spotted owl (Strix occidentalis caurina). Flying squirrels are hypothesized to be limited by den sites (cavities in trees) and by food (truffles). However, no...

A squirrel searches for food at KSC

NASA Technical Reports Server (NTRS)

1999-01-01

An Eastern gray squirrel pauses in its daily search for food in the Merritt Island National Wildlife Refuge, which shares a boundary with Kennedy Space Center. The Eastern gray squirrel is found in wooded, suburban, and urban areas statewide. It nests in tree hollows or leaf nests in treetops. It forages during the day, mainly early morning and late afternoon, both on the ground and in trees, living on a diet of acorns, nuts, fruits, berries, insects, and bird eggs. Food plants include cypress, buckeyes, elms, grapes, tulip trees, mulberries, and tupelo. It breeds in late winter or early spring and again in late spring or summer, bearing two to six young. The eastern gray squirrel chatters when disturbed. The 92,000-acre wildlife refuge is a habitat for more than 310 species of birds, 25 mammals, 117 fishes and 65 amphibians and reptiles.

Avian nestling predation by endangered Mount Graham red squirrel

Treesearch

Claire A. Zugmeyer; John L. Koprowski

2007-01-01

Studies using artificial nests or remote cameras have documented avian predation by red squirrels (Tamiasciurus hudsonicus). Although several direct observations of avian predation events are known in the northern range of the red squirrel distribution, no accounts have been reported in the southern portion. We observed predation upon a hermit thrush...

Use of burrow entrances to indicate densities of Townsend's ground squirrels

USGS Publications Warehouse

Van Horne, Beatrice; Schooley, Robert L.; Knick, Steven T.; Olson, G.S.; Burnham, K.P.

1997-01-01

Counts of burrow entrances have been positively correlated with densities of semi-fossorial rodents and used as an index of densities. We evaluated their effectiveness in indexing densities of Townsend's ground squirrels (Spermophilus townsendii) in the Snake River Birds of Prey National Conservation Area (SRBOPNCA), Idaho, by comparing burrow entrance densities to densities of ground squirrels estimated from livetrapping in 2 consecutive years over which squirrel populations declined by >75%. We did not detect a consistent relation between burrow entrance counts and ground squirrel density estimates within or among habitat types. Scatter plots indicated that burrow entrances had little predictive power at intermediate densities. Burrow entrance counts did not reflect the magnitude of a between-year density decline. Repeated counts of entrances late in the squirrels' active season varied in a manner that would be difficult to use for calibration of transects sampled only once during this period. Annual persistence of burrow entrances varied between habitats. Trained observers were inconsistent in assigning active-inactive status to entrances. We recommend that burrow entrance counts not be used as measures or indices of ground squirrel densities in shrubsteppe habitats, and that the method be verified thoroughly before being used in other habitats.

Trypanosoma cruzi infection of squirrel monkeys: comparison of blood smear examination, commercial enzyme-linked immunosorbent assay, and polymerase chain reaction analysis as screening tests for evaluation of monkey-related injuries.

PubMed

Ndao, M; Kelly, N; Normandin, D; Maclean, J D; Whiteman, A; Kokoskin, E; Arevalo, I; Ward, B J

2000-12-01

Wild-caught New World monkeys (NWM) from Central or South America are often infected with Trypanosoma species, including T. cruzi. In humans, T. cruzi causes Chagas' disease. Even in closed monkey colonies, T. cruzi can be propagated by blood-to-blood exposure, sexual activity, and transplacental transmission. Animal handlers and laboratory staff who deal with blood and tissues from infected NWM are at riskfor acquiring Chagas' disease via accidental exposure. We screened 162 blood samples from wild-caught Saimiri sp. monkeys for Trypanosoma species infections by use of blood smear examination, ELISA, and polymerase chain reaction (PCR) analysis. Blood samples from 19 employees with recent history of monkey-associated injuries also were tested. Six percent (10/162) of the monkey samples were T. cruzi positive on the basis of blood smear examination results, 10.4% (17/162) were positive by ELISA results, and 26.5% (43/162) were positive by PCR results. Other organisms identified by PCR analysis included T. rangeli in two animals, Plasmodium spp. in two animals (P. malariae confirmed by PCR results) and microfilariae in one animal (morphologically, Mansonella perstans). Evidence of trypanosome infection was not found in the 19 employee samples on the basis of results of any of the three aforementioned tests. Close attention must be paid to worker safety where wild-caught NWM are used. The PCR analysis has a clear advantage over conventional techniques (ELISA, blood smear) for screening NWM for trypanosome infections during quarantine and after employee injury.

Squirrel Damage to Pines

Treesearch

USDA Forest Service

1981-01-01

Flagging (dead branch tips) on jack pine and red pine may be caused by insects, diseases, or mechanical damage. In the Lake States, flagging is often the result of mechanical damage, sometimes girdling, caused when the cones are torn off by red squirrels.

Tularemia without lesions in grey tree squirrels: A diagnostic challenge

USDA-ARS?s Scientific Manuscript database

Fifteen cases of Francisella tularenesis infection (tularemia) were identified in western grey (Sciurus griseus) and eastern grey (Sciurus carolinesis) squirrels submitted to the Washington Animal Disease Diagnostic Laboratory between 2008 and 2011. All of the squirrels originated in Washington stat...

Horizontal vestibuloocular reflex evoked by high-acceleration rotations in the squirrel monkey. II. Responses after canal plugging

NASA Technical Reports Server (NTRS)

Lasker, D. M.; Backous, D. D.; Lysakowski, A.; Davis, G. L.; Minor, L. B.

1999-01-01

The horizontal angular vestibuloocular reflex (VOR) evoked by high-frequency, high-acceleration rotations was studied in four squirrel monkeys after unilateral plugging of the three semicircular canals. During the period (1-4 days) that animals were kept in darkness after plugging, the gain during steps of acceleration (3, 000 degrees /s(2), peak velocity = 150 degrees /s) was 0.61 +/- 0.14 (mean +/- SD) for contralesional rotations and 0.33 +/- 0.03 for ipsilesional rotations. Within 18-24 h after animals were returned to light, the VOR gain for contralesional rotations increased to 0. 88 +/- 0.05, whereas there was only a slight increase in the gain for ipsilesional rotations to 0.37 +/- 0.07. A symmetrical increase in the gain measured at the plateau of head velocity was noted after animals were returned to light. The latency of the VOR was 8.2 +/- 0. 4 ms for ipsilesional and 7.1 +/- 0.3 ms for contralesional rotations. The VOR evoked by sinusoidal rotations of 0.5-15 Hz, +/-20 degrees /s had no significant half-cycle asymmetries. The recovery of gain for these responses after plugging was greater at lower than at higher frequencies. Responses to rotations at higher velocities for frequencies >/=4 Hz showed an increase in contralesional half-cycle gain, whereas ipsilesional half-cycle gain was unchanged. A residual response that appeared to be canal and not otolith mediated was noted after plugging of all six semicircular canals. This response increased with frequency to reach a gain of 0.23 +/- 0.03 at 15 Hz, resembling that predicted based on a reduction of the dominant time constant of the canal to 32 ms after plugging. A model incorporating linear and nonlinear pathways was used to simulate the data. The coefficients of this model were determined from data in animals with intact vestibular function. Selective increases in the gain for the linear and nonlinear pathways predicted the changes in recovery observed after canal plugging. An increase in gain of

Epizootiology and pathologic findings associated with a newly described adenovirus in the red squirrel, Sciurus vulgaris.

PubMed

Martínez-Jiménez, David; Graham, David; Couper, David; Benkö, Maria; Schöniger, Sandra; Gurnell, John; Sainsbury, Anthony W

2011-04-01

An infectious disease caused by Squirrelpox virus has contributed to the decline of red squirrels, Sciurus vulgaris, in the British Isles. Because of the heightened disease surveillance activity in red squirrels, adenovirus infection with associated mortality has been detected. Adenoviral disease is described in other rodent species usually associated with stressors. Here we 1) describe the pathologic findings in red squirrels found dead with adenoviral infection and gastrointestinal disease, and 2) investigate the epizootiology of the disease through pathologic investigation, scanning surveillance, and virologic studies. Ten red squirrels involved in conservation studies were diagnosed with adenoviral infection by electron microscopy or PCR. All squirrels exhibited diarrhea and small intestinal inflammation or hemorrhage was evident in seven cases. Lesions indicative of splenic lymphocytolysis were observed in one squirrel and leukocytic hepatitis in another. No adenovirus was detected in grey squirrels, Sciurus carolinensis, inhabiting the same forest area, but previous serologic studies showed that grey squirrels cannot be discounted as a reservoir of the virus. Scanning surveillance showed that 12% of 493 red squirrels had diarrheal disease and two of 13 free-living red squirrels with diarrheal disease had adenovirus infection. Adenoviral disease in declining free-living wild red squirrel populations in the British Isles occurs at a detectable frequency and its impact on the conservation of this species deserves further attention.

Indicators of red squirrel (Tamiasciurus hudonicus) abundance in the whitebark pine zone

USGS Publications Warehouse

Mattson, D.J.; Reinhart, Daniel P.

1996-01-01

We investigated occupied squirrel middens and squirrel sightings and vocalizations as indicators of red squirrel (Tamiasciurus hudsonicus) abundance in the high-elevation whitebark pine (Pinus albicaulis) zone. Data were collected 1984-1989 from line transects located on 2 study sites in the Yellowstone ecosystem. We evaluated the performance of each measure on the basis of precision and biological considerations. We concluded that, of the 3 measures, active middens were the best indicator of red squirrel abundance. We also observed that the density of active middens dropped by 48%-66% between 1987 and 1989, following a severe drought and extensive wildfires that burned one of the study sites during 1988.

Eye model for the ground squirrel

NASA Astrophysics Data System (ADS)

Sussman, Dafna; Chou, B. Ralph; Lakshminarayanan, Vasudevan

2011-11-01

This paper presents an anatomically-correct eye model for the ground squirrel, a diurnal, highly-developed mammal with high visual acuity. This model can assist in understanding the relationship between ocular structural development and its corresponding function. The eye model is constructed based on anatomical measurements of thicknesses and indices of refraction of the various ocular media. The model then derives the gradient index distribution of the crystalline lens using a ray tracing method with a Monte Carlo optimization. Results indicate a diffraction-limited ocular behaviour, implying the visual acuity of the ground squirrel is more likely to be limited by photoreceptor density and diffraction effects, than by ocular geometry.

Seasonal and post-trauma remodeling in cone-dominant ground squirrel retina

PubMed Central

Merriman, Dana K.; Sajdak, Benjamin S.; Li, Wei; Jones, Bryan W.

2016-01-01

With a photoreceptor mosaic containing ~85% cones, the ground squirrel is one of the richest known mammalian sources of these important retinal cells. It also has a visual ecology much like the human’s. While the ground squirrel retina is understandably prominent in the cone biochemistry, physiology, and circuitry literature, far less is known about the remodeling potential of its retinal pigment epithelium, neurons, macroglia, or microglia. This review aims to summarize the data from ground squirrel retina to this point in time, and to relate them to data from other brain areas where appropriate. We begin with a survey of the ground squirrel visual system, making comparisons with traditional rodent models and with human. Because this animal’s status as a hibernator often goes unnoticed in the vision literature, we then present a brief primer on hibernation biology. Next we review what is known about ground squirrel retinal remodeling concurrent with deep torpor and with rapid recovery upon re-warming. Notable here is rapidly-reversible, temperature-dependent structural plasticity of cone ribbon synapses, as well as pre- and post-synaptic plasticity throughout diverse brain regions. It is not yet clear if retinal cell types other than cones engage in torpor-associated synaptic remodeling. We end with the small but intriguing literature on the ground squirrel retina’s remodeling responses to insult by retinal detachment. Notable for widespread loss of (cone) photoreceptors, there is surprisingly little remodeling of the RPE or Müller cells. Microglial activation appears minimal, and remodeling of surviving second- and third-order neurons seems absent, but both require further study. In contrast, traumatic brain injury in the ground squirrel elicits typical macroglial and microglial responses. Overall, the data to date strongly suggest a heretofore unrecognized, natural checkpoint between retinal deafferentiation and RPE and Müller cell remodeling events. As

Daily and seasonal activity patterns in the eastern gray squirrel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bland, M.E.

1977-03-01

The daily and seasonal activity patterns of the eastern gray squirrel were investigated between July 1, 1971 and September 16, 1972. Seasonal variations existed in the amount of time per day squirrels were active, the time of onset and cessation of activity, and the size of home range. Squirrels were most active in the fall and spring and least active in the winter. Two peaks in activity (morning and evening) with a mid-day resting period were characteristic of the summer activity pattern. During the winter one brief period of activity occurred during the warm mid-day hours. In the fall themore » time of onset of activity was consistent and occurred 20 to 30 minutes before sunrise. Cessation of activity was also regular and took place 20 to 30 minutes after sunset. Times of onset and cessation of activity were irregular during the winter and summer with onset usually occurring after sunrise and cessation before sunset. Home range size was smallest in winter and largest in late spring and late summer. Male and female range sizes were similar in fall and winter but in the spring and summer ranges of males exceeded those of females. During winter one night nest location was used per given two week period and daytime activity was restricted to the area around the den site. In spring, summer, and fall each squirrel used between two and three nest locations per two week period and squirrels traveled considerable distance from the den site. Hardwood and cedar forests were heavily utilized by the squirrels with approximately 53 percent of the locations occurring in hardwood forests and 38 percent in cedar forests. Correlations between the amount of time per day squirrels were active and various abiotic and biotic factors were made. Snow cover and/or extremely cold temperatures during the winter and early spring curtailed movement, and rainy weather in summer decreased activity. The availability of acorns in the autumn and the appearance of food in the spring increased

Pharmacokinetic modeling: Prediction and evaluation of route dependent dosimetry of bisphenol A in monkeys with extrapolation to humans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisher, Jeffrey W., E-mail: jeffrey.fisher@fda.hhs.gov; Twaddle, Nathan C.; Vanlandingham, Michelle

A physiologically based pharmacokinetic (PBPK) model was developed for bisphenol A (BPA) in adult rhesus monkeys using intravenous (iv) and oral bolus doses of 100 {mu}g d6-BPA/kg (). This calibrated PBPK adult monkey model for BPA was then evaluated against published monkey kinetic studies with BPA. Using two versions of the adult monkey model based on monkey BPA kinetic data from and , the aglycone BPA pharmacokinetics were simulated for human oral ingestion of 5 mg d16-BPA per person (Voelkel et al., 2002). Voelkel et al. were unable to detect the aglycone BPA in plasma, but were able to detectmore » BPA metabolites. These human model predictions of the aglycone BPA in plasma were then compared to previously published PBPK model predictions obtained by simulating the Voelkel et al. kinetic study. Our BPA human model, using two parameter sets reflecting two adult monkey studies, both predicted lower aglycone levels in human serum than the previous human BPA PBPK model predictions. BPA was metabolized at all ages of monkey (PND 5 to adult) by the gut wall and liver. However, the hepatic metabolism of BPA and systemic clearance of its phase II metabolites appear to be slower in younger monkeys than adults. The use of the current non-human primate BPA model parameters provides more confidence in predicting the aglycone BPA in serum levels in humans after oral ingestion of BPA. -- Highlights: Black-Right-Pointing-Pointer A bisphenol A (BPA) PBPK model for the infant and adult monkey was constructed. Black-Right-Pointing-Pointer The hepatic metabolic rate of BPA increased with age of the monkey. Black-Right-Pointing-Pointer The systemic clearance rate of metabolites increased with age of the monkey. Black-Right-Pointing-Pointer Gut wall metabolism of orally administered BPA was substantial across all ages of monkeys. Black-Right-Pointing-Pointer Aglycone BPA plasma concentrations were predicted in humans orally given oral doses of deuterated BPA.« less

Short-term fasting attenuates the response of the HPG axis to kisspeptin challenge in the adult male rhesus monkey (Macaca mulatta).

PubMed

Wahab, Fazal; Aziz, Farzana; Irfan, Shahzad; Zaman, Waheed-Uz; Shahab, Muhammad

2008-11-07

In primates, changes in nutritional status affect the hypothalamic-pituitary-gonadal (HPG) axis by still poorly understood mechanisms. Recently, hypothalamic kisspeptin-GPR54 signaling has emerged as a significant regulator of this neuroendocrine axis. The present study was designed to examine whether suppression of the reproductive function by acute food-restriction in a non-human primate is mediated by decreased responsiveness of the HPG axis to endogenous kisspeptin drive. Five intact adult male rhesus monkeys habituated to chair-restraint, received intravenous boli of human kisspeptin-10 (KP10, 50 microg), hCG (50 IU), and vehicle (1 ml) in both fed and 48-h fasting conditions. Plasma concentrations of glucose, cortisol and testosterone (T) were measured by using enzymatic and specific RIAs, respectively. The acute 48-h fasting decreased plasma glucose (P<0.01) and T (P<0.005) levels, and increased cortisol levels (P<0.05). KP10 administration caused a robust stimulation of T secretion in both fed and fasted monkeys. However, mean T concentration and T AUC after KP10 administration were significantly (P<0.01-0.005) reduced in fasted monkeys. Likewise, the time of the first significant increase in post-KP10 T levels was also significantly (P<0.01) delayed. T response to hCG stimulation was similar in fed and fasted monkeys. The present results indicate that under fasting conditions the KP10 induced T response is delayed and suppressed. These data support the notion that fasting-induced suppression of the HPG axis in the adult male rhesus monkey may involve, at least in part, a reduction in the sensitivity of the GnRH neuronal network to endogenous kisspeptin stimulation.

Thermoregulation is impaired in an environment without circadian time cues

NASA Technical Reports Server (NTRS)

Fuller, C. A.; Sulzman, F. M.; Moore-Ede, M. C.

1978-01-01

Thirteen adult male squirrel monkeys were restrained to a metabolism chair for periods of two or more weeks within an isolation chamber having controlled environmental lighting and ambient temperature. The monkeys were subjected to mild 6-hour cold exposures at all circadian phases of the day. It was found that a prominent circadian rhythm in body temperature, regulated against mild cold exposure, was present in those monkeys synchronized in a 24-hour light-dark cycle. Cold exposures were found to produce decreased core body temperatures when the circadian rhythms were free running or when environmental time indicators were not present. It is concluded that the thermoregulating system depends on the internal synchronization of the circadian time-keeping system.

Demonstration of line transect methodologies to estimate urban gray squirrel density

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hein, E.W.

1997-11-01

Because studies estimating density of gray squirrels (Sciurus carolinensis) have been labor intensive and costly, I demonstrate the use of line transect surveys to estimate gray squirrel density and determine the costs of conducting surveys to achieve precise estimates. Density estimates are based on four transacts that were surveyed five times from 30 June to 9 July 1994. Using the program DISTANCE, I estimated there were 4.7 (95% Cl = 1.86-11.92) gray squirrels/ha on the Clemson University campus. Eleven additional surveys would have decreased the percent coefficient of variation from 30% to 20% and would have cost approximately $114. Estimatingmore » urban gray squirrel density using line transect surveys is cost effective and can provide unbiased estimates of density, provided that none of the assumptions of distance sampling theory are violated.« less

Comparison of synchronization of primate circadian rhythms by light and food

NASA Technical Reports Server (NTRS)

Sulzman, F. M.; Fuller, C. A.; Moore-Ede, M. C.

1978-01-01

It is a well-documented fact that cycles of light and dark (LD) are the major entraining agent or 'zeitgeber' for circadian rhythms and that cycles of eating and fasting (EF) are capable of synchronizing a few circadian rhythms in the squirrel monkey. In this paper, by contrasting how these rhythms are timed by LD and EF cycles, the differential coupling to the oscillating system within adult male squirrel monkeys is examined. The variables measured are the rhythms of drinking, colonic temperature, and urinary potassium and water excretion. Attention is given to a comparison of the reproducibility of the averaged waveforms of the rhythms, the stability of the timing of a phase reference point, and the rate of resynchronization of these rhythms following an abrupt 8-hr phase delay in the zeitgeber. It is shown that the colonic temperature rhythm is more tightly controlled by LD than EF cycles, and that the drinking and urinary rhythms are more tightly coupled to EF than LD cycles.

SOME EVIDENCE OF PSYCHIC BLINDNESS IN MONKEYS WITH FOCAL-HEAD IRRADIATION OF THE TEMPORAL LOBES

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDowell, A.A.; Brown, W.L.

1963-12-01

This study was conducted to compare the effects of various extra-cage social stimuli on the free-cage behavior of normal monkeys and of monkeys with previous focal-head irradiation. Four control and four focal-head irradiated monkeys with nearly identical training histories were used, the latter being the survivors of a focal-head irradiation study conducted 41/2 yr earlier. They had received 3000 r x radiation to an area of the head containing the inferior parietal lobule and posterior aspect of the temporal lobe, and repeated 30 days later Each group was systematically observed under each of four socialstimulus conditions with the order ofmore » condition presentation counterbalanced within each group over a 4-day period. The four social-stimulus conditions included: absence of social stimulus, an adult male monkey, an adult female monkey at menses, and an adult female monkey at estimated time of ovulation. The socialstimulus conditions showed no effect on the nondirected activities of the normal monkeys, but produced a marked decrease in the nondirected activities of the focal-head irradiated monkeys, with the least number of such activities being manifest in the presence of the adult female monkey at ovulation. Under conditions of social stimulation the normal monkeys showed a marked decrease in total directed activities of the non-social-stimulus condition, while the focal-head irradiated monkeys showed a marked increase, the effect in each instance being greatest in the presence of the female at ovulation. The directed activities, toward the cage as an object, of the controls decreasrd and those of the experimental subjects increased. The controls were more than twice as responsive to the female at estimated time of ovulation as to the other two social stimuli, while the experimental monkeys were equally responsive to each of the three social stimuli. The data suggest the presence of psychic blindness in the monkeys previously exposed to focal

Nest trees of northern flying squirrels in the Sierra Nevada

Treesearch

Marc D. Meyer; Douglas A. Kelt; Malcolm P. North

2005-01-01

We examined the nest-tree preferences of northern flying squirrels (Glaucomys sabrinus) in an old-growth, mixed-conifer and red fir (Abies magnifica) forest of the southern Sierra Nevada of California. We tracked 27 individuals to 122 nest trees during 3 summers. Flying squirrels selected nest trees that were larger in diameter and...

Monitoring interactions between red-cockaded woodpeckers and southern flying squirrels

Treesearch

Thomas S. Risch; Susan C. Loeb

2004-01-01

Although several studies have suggested that southern flying squirrels (Glaucomys volans) may have a signif- icant negative impact on red-cockaded woodpeckers (Picoides borealis) (Loeb and Hooper 1997, Laves and Loeb 1999), the nature of the interactions between the species remains unclear. Particularly lacking are data that address if southern flying squirrels...

Postnatal change in sulcal length asymmetry in cerebrum of cynomolgus monkeys (Macaca fascicularis).

PubMed

Sakamoto, Kazuhito; Sawada, Kazuhiko; Fukunishi, Katsuhiro; Noritaka, Imai; Sakata-Haga, Hiromi; Yoshihiro, Fukui

2014-02-01

The purpose of this study was to determine the timing of the onset of adult-type sulcal length asymmetry during postnatal development of the male cynomolgus monkey cerebrum. The monkey brain has already reached adult size by 3 months of age, although the body weight only represents 1/8 of the adult body weight by that time. The fronto-occipital length and the cerebral width also reached adult levels by that postnatal age with no left/right bias. Consistently, lengths of the major primary sulci reached adult levels by 3 months of age, and then decreased slightly in sexually mature monkeys (4-6.5 years of age). Asymmetry quotient analysis showed that sulcal length asymmetry patterns gradually changed during postnatal development. The male adult pattern of sulcal length asymmetry was acquired after 24 months of age. In particular, age-dependent rightward lateralization of the arcuate sulcal length was revealed during cerebral maturation by three-way ANOVA. The results suggest that the regional difference in cerebral maturation from adolescence to young adulthood modifies the sulcal morphology with characteristic asymmetric patterns in male cynomolgus monkeys. Copyright © 2013 Wiley Periodicals, Inc.

The potential role of strongyloides robustus on parasite-mediated competition between two species of flying squirrels (Glaucomys).

PubMed

Krichbaum, Kristle; Mahan, Carolyn G; Steele, Michael A; Turner, Gregory; Hudson, Peter J

2010-01-01

There is growing evidence that populations of the northern flying squirrel (Glaucomys sabrinus) are declining in the eastern United States, perhaps due to competition with the southern flying squirrel (Glaucomys volans). Potential causes include parasite-mediated or apparent competition from the shared intestinal nematode, Strongyloides robustus, which has been shown to detrimentally affect the northern flying squirrel but not the southern flying squirrel. To investigate this hypothesis, we conducted a preliminary study on the parasite community of both flying squirrel species from sites in Pennsylvania where the two species occur sympatrically and where G. sabrinus is now considered endangered at the state level. We compared these parasite communities with those from northern flying squirrels from northern New York where the southern flying squirrel is absent. We found eight species of gastrointestinal parasites (Pterygodermatites peromysci, Lemuricola sciuri, Syphacia thompsoni, Syphacia spp., Capillaria spp., Citellinema bifurcatum, Strogyloides robustus, and an unidentifiable cestode species) in both species of flying squirrels examined for our study. The parasite-mediated competition hypothesis was partially supported. For example, in Pennsylvania, S. robustus was overdispersed in southern flying squirrels, such that a small proportion of the hosts carried a large proportion of the worm population. In addition, we found S. robustus to be present in northern flying squirrels when the species were sympatric, but not where southern flying squirrels were absent in New York. However, there was no association between S. robustus and the body condition of flying squirrels. We detected a potential parasite community interaction, as S. robustus abundance was positively associated with P. peromysci.

Status and habitat relationships of northern flying squirrels on Mount Desert Island, Maine

USGS Publications Warehouse

O'Connell, A.F.; Servello, F.; Higgins, J.; Halteman, W.

2001-01-01

Northern (Glaucomys sabrinus) and southern (G. volans) flying squirrels occur in Maine, but there is uncertainty about range overlap in southcentral Maine where the southern flying squirrel reaches its geographic range limit. We surveyed flying squirrels on Mount Desert Island (MDI), located along the central Maine coast, to update the current status and distribution of these species. We captured only northern flying squirrels, and populations (> 2 individuals) were located in two conifer stands and one mixed conifer-hardwood stand. All three stands were located in relatively older forests, outside a large area burned in a 1947 fire. Tree diameters were similar between trap stations with and without captures, under-story density was low overall, and there was a trend of higher seedling density at capture locations. Low understory density may allow squirrels more effective gliding movements between trees, which may enhance predator avoidance. Although the southern flying squirrel was reported from MDI numerous times during the 20th century, no voucher specimens exist, and species identification and localities have been poorly documented. Future surveys on MDI should consider collection of voucher specimens to validate subsequent survey efforts and effectively document changes in local biodiversity.

Movements of northern flying squirrels in different-aged forest stands of western Oregon

USGS Publications Warehouse

Martin, K.J.; Anthony, R.G.

1999-01-01

In western Oregon, northern flying squirrels (Glaucomys sabrinus) are the primary prey species for northern spotted owls (Strix occidentalis caurina), an old-growth associated species. To assess differences between old-growth and second-growth habitat, we livetrapped and radiotagged 39 northern flying squirrels to estimate their home range sizes and describe movements in 2 old-growth and 2 second-growth conifer forest stands in the Cascade Mountains of central Oregon. Sampling periods were summer and fall of 1991-92. Home range sizes averaged 4.9 ha and did not differ (P > 0.30) between the 2 stand types. Male northern flying squirrels had larger (P ??? 0.03) mean home ranges (5.9 ?? 0.8 ha; ?? ?? SE; n = 20) than females (3.9 ?? 0.4 ha; n = 19). Northern flying squirrel movement distances between successive, noncorrelated telemetry locations averaged 71 m (n = 1,090). No correlation was found between distances moved and stand type or sex. Northern flying squirrel's home range sizes, movements, and densities were similar between the 2 stand types. We suggest abundance and movements of northern flying squirrels are not influencing the preferential selection of oldgrowth forests by northern spotted owls.

Current status of the western gray squirrel population in the Puget Trough, Washington.

Treesearch

R. Bayrakci; A.B. Carey; T.M. Wilson

2001-01-01

The Puget Trough population of Washington’s state-threatened western gray squirrel is centered in Oregon white oak ecotones adjacent to conifer forests and prairies on the Fort Lewis Military Reservation. Our goal was to determine the current status of western gray squirrels in this region. In 1998, we found five western gray squirrels in 538 hours of foot surveys in...

FLOTAC for diagnosis of endo-parasites in pet squirrels in southern Italy.

PubMed

d'Ovidio, D; Rinaldi, L; Ianniello, D; Donnelly, T M; Pepe, P; Capasso, M; Cringoli, G

2014-02-24

The present study investigated the occurrence of endoparasites in pet squirrels in southern Italy. Fresh fecal samples were collected from 50 asymptomatic pet squirrels belonging to five different species (Callosciurus finlaysonii, n=6, C. prevosti, n=6; Tamias striatus, n=26, T. sibiricus, n=10; Sciurus carolinensis, n=2) housed both in pet shops and/or in private residences. All fecal samples were processed using the FLOTAC pellet technique to identify and count helminth eggs/larvae and protozoan cysts/oocysts. In addition, to detect Cryptosporidium spp. and Giardia spp. the samples were analyzed by the Remel Xpect(®) immunoassay. Helminth eggs were detected in 9 out of 50 squirrels. Specifically, eggs of Dicrocoelium dendriticum were found in 5 squirrels (C. finlaysonii, n=2; C. prevosti, n=2; T. striatus, n=1); eggs of the pinworm Syphacia spp. in 3 squirrels (C. prevosti, n=2; T. striatus, n=1); and eggs of gastrointestinal nematoda (Nippostrongylus-like) were found in 1 subject (C. prevosti). Finally, two squirrels (C. prevosti) had multiple parasitic infections with D. dendriticum and Capillaria hepatica, and with D. dendriticum and Strongyloides spp., respectively. None of the samples were positive for Cryptosporidium spp. or Giardia spp. or any other protozoa (e.g. Eimeria). To the authors' knowledge, this is the first report of a D. dendriticum natural infection in pet rodents. Copyright © 2013 Elsevier B.V. All rights reserved.

Daily Activity and Nest Occupation Patterns of Fox Squirrels (Sciurus niger) throughout the Year.

PubMed

Wassmer, Thomas; Refinetti, Roberto

2016-01-01

The authors investigated the general activity and nest occupation patterns of fox squirrels in a natural setting using temperature-sensitive data loggers that measure activity as changes in the microenvironment of the animal. Data were obtained from 25 distinct preparations, upon 14 unique squirrels, totaling 1385 recording days. The animals were clearly diurnal, with a predominantly unimodal activity pattern, although individual squirrels occasionally exhibited bimodal patterns, particularly in the spring and summer. Even during the short days of winter (9 hours of light), the squirrels typically left the nest after dawn and returned before dusk, spending only about 7 hours out of the nest each day. Although the duration of the daily active phase did not change with the seasons, the squirrels exited the nest earlier in the day when the days became longer in the summer and exited the nest later in the day when the days became shorter in the winter, thus tracking dawn along the seasons. During the few hours spent outside the nest each day, fox squirrels seemed to spend most of the time sitting or lying. These findings suggest that fox squirrels may have adopted a slow life history strategy that involves long periods of rest on trees and short periods of ground activity each day.

Population density-dependent hair cortisol concentrations in rhesus monkeys (Macaca mulatta)

PubMed Central

Dettmer, A.M.; Novak, M.A.; Meyer, J.S.; Suomi, S.J.

2014-01-01

Summary Population density is known to influence acute measures of hypothalamic-pituitary-adrenal (HPA) axis activity in a variety of species, including fish, deer, birds, and humans. However, the effects of population density on levels of chronic stress are unknown. Given the fact that exposure to chronically elevated levels of circulating glucocorticoids results in a host of health disparities in animals and humans alike, it is important to understand how population density may impact chronic stress. We assessed hair cortisol concentrations (HCCs), which are reliable indicators of chronic HPA axis activity, in rhesus monkeys (Macaca mulatta) to determine the influence of population density on these values. In Experiment 1, we compared HCCs of monkeys living in high-density (HD; 1 monkey/0.87m2) and low-density (LD; 1 monkey/63.37m2) environments (N=236 hair samples) and found that HD monkeys exhibited higher hair cortisol across all age categories (infant, juvenile, young adult, adult, and aged) except infancy and aged (F(5)=4.240, p=0.001), for which differences were nearly significant. HD monkeys also received more severe fight wounds than LD monkeys (χ2=26.053, p<0.001), though no effects of dominance status emerged. In Experiment 2, we examined how HCCs change with fluctuating population levels across five years in the adult LD monkeys (N=155 hair samples) and found that increased population density was significantly positively correlated with HCCs in this semi-naturalistic population (r(s)=0.975, p=0.005). These are the first findings to demonstrate that increased population density is associated with increased chronic, endogenous glucocorticoid exposure in a nonhuman primate species. We discuss the implications of these findings with respect to laboratory research, population ecology, and human epidemiology. PMID:24636502

Population density-dependent hair cortisol concentrations in rhesus monkeys (Macaca mulatta).

PubMed

Dettmer, A M; Novak, M A; Meyer, J S; Suomi, S J

2014-04-01

Population density is known to influence acute measures of hypothalamic-pituitary-adrenal (HPA) axis activity in a variety of species, including fish, deer, birds, and humans. However, the effects of population density on levels of chronic stress are unknown. Given the fact that exposure to chronically elevated levels of circulating glucocorticoids results in a host of health disparities in animals and humans alike, it is important to understand how population density may impact chronic stress. We assessed hair cortisol concentrations (HCCs), which are reliable indicators of chronic HPA axis activity, in rhesus monkeys (Macaca mulatta) to determine the influence of population density on these values. In Experiment 1, we compared HCCs of monkeys living in high-density (HD; 1 monkey/0.87m(2)) and low-density (LD; 1 monkey/63.37m(2)) environments (N=236 hair samples) and found that HD monkeys exhibited higher hair cortisol across all age categories (infant, juvenile, young adult, adult, and aged) except infancy and aged (F(5)=4.240, p=0.001), for which differences were nearly significant. HD monkeys also received more severe fight wounds than LD monkeys (χ(2)=26.053, p<0.001), though no effects of dominance status emerged. In Experiment 2, we examined how HCCs change with fluctuating population levels across 5 years in the adult LD monkeys (N=155 hair samples) and found that increased population density was significantly positively correlated with HCCs in this semi-naturalistic population (r(s)=0.975, p=0.005). These are the first findings to demonstrate that increased population density is associated with increased chronic, endogenous glucocorticoid exposure in a nonhuman primate species. We discuss the implications of these findings with respect to laboratory research, population ecology, and human epidemiology. Published by Elsevier Ltd.

Yield from an intensively hunted population of eastern fox squirrels

Treesearch

James S. Jordan; James S. Jordan

1971-01-01

Rates at which Eastern fox squirrels (Sciurus niger) are exploited in areas open to public hunting may be useful guides for designing fall hunting seasons that are biologically defensible. However, there is a question whether the harvest of fox squirrels by public hunting will even occasionally be great enough to challenge the limit allowed by the best designed...

Predation risk landscape modifies flying and red squirrel nest site occupancy independently of habitat amount

PubMed Central

Korpimäki, Erkki; Villers, Alexandre; Selonen, Vesa

2018-01-01

Habitat choice often entails trade-offs between food availability and predation risk. Understanding the distribution of individuals in space thus requires that both habitat characteristics and predation risk are considered simultaneously. Here, we studied the nest box use of two arboreal squirrels who share preferred habitat with their main predators. Nocturnal Ural owls (Strix uralensis) decreased occurrence of night-active flying squirrels (Pteromys volans) and diurnal goshawks (Accipiter gentilis) that of day-active red squirrels (Sciurus vulgaris). Unexpectedly, the amount of preferred habitat had no effect on nest box use, but, surprisingly, both squirrel species seemed to benefit from close proximity to agricultural fields and red squirrels to urban areas. We found no evidence of trade-off between settling in a high-quality habitat and avoiding predators. However, the amount of poor-quality young pine forests was lower in occupied sites where goshawks were present, possibly indicating habitat specific predation on red squirrels. The results suggest that erecting nest boxes for Ural owls should be avoided in the vicinity of flying squirrel territories in order to conserve the near threatened flying squirrels. Our results also suggest that flying squirrels do not always need continuous old forests, and hence the currently insufficient conservation practices could be improved with reasonable increases in the areas left untouched around their nests. The results of this study demonstrate the importance of taking into account both habitat requirements and predation risk as well as their interactive effects when modeling the occupancy of threatened animal species and planning their conservation. PMID:29596438

Fire, red squirrels, whitebark pine, and Yellowstone grizzly bears

USGS Publications Warehouse

Podruzny, Shannon; Reinhart, Daniel P.; Mattson, David J.

1999-01-01

Whitebark pine (Pinus albicaulis) habitats are important to Yellowstone grizzly bears (Ursus arctos) as refugia and sources of food. Ecological relationships between whitebark pine, red squirrels (Tamiasciurus hudsonicus), and grizzly bear use of pine seeds on Mt. Washburn in Yellowstone National Park, Wyoming, were examined during 1984-86. Following large-scale fires in 1988, we repeated the study in 1995-97 to examine the effects of fire on availability of whitebark pine seed in red squirrel middens and on bear use of middens. Half of the total length of the original line transects burned. We found no red squirrel middens in burned areas. Post-fire linear-abundance (no./km) of active squirrel middens that were pooled from burned and unburned areas decreased 27% compared to pre-fire abundance, but increased in unburned portions of some habitat types. Mean size of active middens decreased 54% post-fire. Use of pine seeds by bears (linear abundance of excavated middens) in pooled burned and unburned habitats decreased by 64%, likely due to the combined effects of reduced midden availability and smaller midden size. We discourage any further large-scale losses of seed producing trees from management-prescribed fires or timber harvesting until the effects of fire on ecological relationships in the whitebark pine zone are better understood.

Seasonal use of red-cockaded woodpecker cavities by southern flying squirrels

Treesearch

Susan C. Loeb; Deanna L. Ruth

2004-01-01

Southern flying squirrels (Glaucomys volans) can significantly impact red-cockaded woodpecker reproductive success (Laves and Loeb 1999). Thus, exclusion or removal of flying squirrels from red-cockaded woodpecker cavities and clusters may be warranted in small woodpecker populations (U.S. Fish and Wildlife Service 2003). However, development of...

Sexing the Sciuridae: a simple and accurate set of molecular methods to determine sex in tree squirrels, ground squirrels and marmots.

PubMed

Gorrell, Jamieson C; Boutin, Stan; Raveh, Shirley; Neuhaus, Peter; Côté, Steeve D; Coltman, David W

2012-09-01

We determined the sequence of the male-specific minor histocompatibility complex antigen (Smcy) from the Y chromosome of seven squirrel species (Sciuridae, Rodentia). Based on conserved regions inside the Smcy intron sequence, we designed PCR primers for sex determination in these species that can be co-amplified with nuclear loci as controls. PCR co-amplification yields two products for males and one for females that are easily visualized as bands by agarose gel electrophoresis. Our method provides simple and reliable sex determination across a wide range of squirrel species. © 2012 Blackwell Publishing Ltd.

Kleptoparasitic behavior and species richness at Mt. Graham red squirrel middens

Treesearch

Andrew J. Edelman; John L. Koprowski; Jennifer L. Edelman

2005-01-01

We used remote photography to assess the frequency of inter- and intra-specific kleptoparasitism and species richness at Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis) middens. Remote cameras and conifer cones were placed at occupied and unoccupied middens, and random sites. Species richness of small mammals was higher at red squirrel...

Spatial Relational Memory in 9-Month-Old Macaque Monkeys

ERIC Educational Resources Information Center

Lavenex, Pierre; Lavenex, Pamela Banta

2006-01-01

This experiment assesses spatial and nonspatial relational memory in freely moving 9-mo-old and adult (11-13-yr-old) macaque monkeys ("Macaca mulatta"). We tested the use of proximal landmarks, two different objects placed at the center of an open-field arena, as conditional cues allowing monkeys to predict the location of food rewards hidden in…

The Autopsy of Squirrel Doe

ERIC Educational Resources Information Center

Dick, Timothy T.; Watson, Jason

2005-01-01

Introductory biology laboratory experiences frequently rely on preserved chordates for anatomical study. Unfortunately, these preserved organisms rarely reflect the appearance of a living creature. Since community colleges are generally prohibited the use of live chordates, this paper describes the autopsy of a "road kill" squirrel to facilitate…

Cloning of Macaque Monkeys by Somatic Cell Nuclear Transfer.

PubMed

Liu, Zhen; Cai, Yijun; Wang, Yan; Nie, Yanhong; Zhang, Chenchen; Xu, Yuting; Zhang, Xiaotong; Lu, Yong; Wang, Zhanyang; Poo, Muming; Sun, Qiang

2018-02-08

Generation of genetically uniform non-human primates may help to establish animal models for primate biology and biomedical research. In this study, we have successfully cloned cynomolgus monkeys (Macaca fascicularis) by somatic cell nuclear transfer (SCNT). We found that injection of H3K9me3 demethylase Kdm4d mRNA and treatment with histone deacetylase inhibitor trichostatin A at one-cell stage following SCNT greatly improved blastocyst development and pregnancy rate of transplanted SCNT embryos in surrogate monkeys. For SCNT using fetal monkey fibroblasts, 6 pregnancies were confirmed in 21 surrogates and yielded 2 healthy babies. For SCNT using adult monkey cumulus cells, 22 pregnancies were confirmed in 42 surrogates and yielded 2 babies that were short-lived. In both cases, genetic analyses confirmed that the nuclear DNA and mitochondria DNA of the monkey offspring originated from the nucleus donor cell and the oocyte donor monkey, respectively. Thus, cloning macaque monkeys by SCNT is feasible using fetal fibroblasts. Copyright © 2018 Elsevier Inc. All rights reserved.

Sporadic Premature Aging in a Japanese Monkey: A Primate Model for Progeria

PubMed Central

Oishi, Takao; Imai, Hiroo; Go, Yasuhiro; Imamura, Masanori; Hirai, Hirohisa; Takada, Masahiko

2014-01-01

In our institute, we have recently found a child Japanese monkey who is characterized by deep wrinkles of the skin and cataract of bilateral eyes. Numbers of analyses were performed to identify symptoms representing different aspects of aging. In this monkey, the cell cycle of fibroblasts at early passage was significantly extended as compared to a normal control. Moreover, both the appearance of senescent cells and the deficiency in DNA repair were observed. Also, pathological examination showed that this monkey has poikiloderma with superficial telangiectasia, and biochemical assay confirmed that levels of HbA1c and urinary hyaluronan were higher than those of other (child, adult, and aged) monkey groups. Of particular interest was that our MRI analysis revealed expansion of the cerebral sulci and lateral ventricles probably due to shrinkage of the cerebral cortex and the hippocampus. In addition, the conduction velocity of a peripheral sensory but not motor nerve was lower than in adult and child monkeys, and as low as in aged monkeys. However, we could not detect any individual-unique mutations of known genes responsible for major progeroid syndromes. The present results indicate that the monkey suffers from a kind of progeria that is not necessarily typical to human progeroid syndromes. PMID:25365557

Red-cockaded woodpecker cavity tree resin avoidance by southern flying squirrels

Treesearch

Richard R. Schaefer; Daniel Saenz

1998-01-01

While examining red-cockaded woodpecker (Picoides borealis) cavity contents in eastern Texas, the authors observed cavity tree resin avoidance by southern flying squirrels (Glaucomys volans). The tree surface around an active red-cockaded woodpecker cavity is coated with sticky resin which flows from resin wells created by the woodpecker. The southern flying squirrel...

Maturation and reproduction of northern flying squirrels in Pacific Northwest forests.

Treesearch

Lisa J. Villa; Andrew B. Carey; Todd M. Wilson; Karma E. Glos

1999-01-01

Northern flying squirrels are the primary prey of northern spotted owls and are important dispersers of fungal spores in Pacific Northwest forests. Despite the importance of these squirrels in forest ecosystems, information is lacking on life history and methods for determining age and reproductive condition. In the laboratory, we measured epiphyseal notch, femur...

Short-term responses of red squirrels to prescribed burning in the interior Pacific Northwest, USA

Treesearch

Robin E. Russell; John F. Lehmkuhl; Stephen T. Buckland; Victoria A. Saab

2010-01-01

We quantified changes in density of red squirrels (Tamiasciurus hudsonicus) in response to prescribed fire in mixed coniferous forests of Idaho and Washington, USA, using a Before-After-Control-Impact design. We found no evidence that low-severity prescribed fires affected density of red squirrels; we estimated the change in red squirrel densities...

Psychomotor stimulant effects of beta-phenylethylamine in monkeys treated with MAO-B inhibitors.

PubMed

Bergman, J; Yasar, S; Winger, G

2001-12-01

Sufficiently high doses of beta-phenylethylamine (beta-PEA), a trace amine that is rapidly metabolized by monoamine oxidase-type B (MAO-B), can produce effects comparable to those of cocaine or methamphetamine (MA). The present experiments were conducted to study how the discriminative-stimulus (S(D)) and reinforcing-stimulus (S(R)) effects of beta-PEA in monkeys are modified by treatment with inhibitors of MAO-B [R-(-)-deprenyl and MDL 72974]. In studies of its S(D) effects, doses of beta-PEA up to 30 mg/kg engendered only sporadic responding on the drug-associated lever in squirrel monkeys that discriminated intramuscular injections of 0.3 mg/kg MA from vehicle whereas lower doses of 0.3-1.0 mg/kg beta-PEA produced full substitution when administered after either R-(-)-deprenyl or MDL 72974 (0.3 mg/kg). The MA-like S(D) effects of beta-PEA were attenuated by either dopamine D(1) or D(2) receptor blockers. In studies of its S(R) effects, high doses of beta-PEA maintained responding in two of three monkeys under a second-order fixed-interval schedule (3.0 or 10 mg/kg per injection) and two of three monkeys under a simple fixed ratio (FR) schedule (0.3-1.0 mg/kg per injection) of intravenous (i.v.) self-administration. MAO-B inhibition by R-(-)-deprenyl or MDL 72974 enhanced the S(R) effects of beta-PEA in all monkeys and, under the FR schedule, induced a 30-fold or greater leftward shift in the dose-response function for its i.v. self-administration. Based on time-course determinations, the enhanced S(R) effects of beta-PEA under the FR schedule were long-lasting and dissipated gradually over 3-7 days. These results show that inhibition of MAO-B enhances S(D) and S(R) effects of beta-PEA in monkeys, presumably by delaying its inactivation. MAO-B inhibition leading to increased levels of beta-PEA may be useful, alone or in combination with other therapeutic agents, in the pharmacological management of selected aspects of drug dependence.

Relative roles of grey squirrels, supplementary feeding, and habitat in shaping urban bird assemblages.

PubMed

Bonnington, Colin; Gaston, Kevin J; Evans, Karl L

2014-01-01

Non-native species are frequently considered to influence urban assemblages. The grey squirrel Sciurus carolinensis is one such species that is widespread in the UK and is starting to spread across Europe; it predates birds' nests and can compete with birds for supplementary food. Using distance sampling across the urbanisation intensity gradient in Sheffield (UK) we test whether urban grey squirrels influence avian species richness and density through nest predation and competition for supplementary food sources. We also assess how urban bird assemblages respond to supplementary feeding. We find that grey squirrels slightly reduced the abundance of breeding bird species most sensitive to squirrel nest predation by reducing the beneficial impact of woodland cover. There was no evidence that grey squirrel presence altered relationships between supplementary feeding and avian assemblage structure. This may be because, somewhat surprisingly, supplementary feeding was not associated with the richness or density of wintering bird assemblages. These associations were positive during the summer, supporting advocacy to feed birds during the breeding season and not just winter, but explanatory capacity was limited. The amount of green space and its quality, assessed as canopy cover, had a stronger influence on avian species richness and population size than the presence of grey squirrels and supplementary feeding stations. Urban bird populations are thus more likely to benefit from investment in improving the availability of high quality habitats than controlling squirrel populations or increased investment in supplementary feeding.

Relative Roles of Grey Squirrels, Supplementary Feeding, and Habitat in Shaping Urban Bird Assemblages

PubMed Central

Bonnington, Colin; Gaston, Kevin J.; Evans, Karl L.

2014-01-01

Non-native species are frequently considered to influence urban assemblages. The grey squirrel Sciurus carolinensis is one such species that is widespread in the UK and is starting to spread across Europe; it predates birds’ nests and can compete with birds for supplementary food. Using distance sampling across the urbanisation intensity gradient in Sheffield (UK) we test whether urban grey squirrels influence avian species richness and density through nest predation and competition for supplementary food sources. We also assess how urban bird assemblages respond to supplementary feeding. We find that grey squirrels slightly reduced the abundance of breeding bird species most sensitive to squirrel nest predation by reducing the beneficial impact of woodland cover. There was no evidence that grey squirrel presence altered relationships between supplementary feeding and avian assemblage structure. This may be because, somewhat surprisingly, supplementary feeding was not associated with the richness or density of wintering bird assemblages. These associations were positive during the summer, supporting advocacy to feed birds during the breeding season and not just winter, but explanatory capacity was limited. The amount of green space and its quality, assessed as canopy cover, had a stronger influence on avian species richness and population size than the presence of grey squirrels and supplementary feeding stations. Urban bird populations are thus more likely to benefit from investment in improving the availability of high quality habitats than controlling squirrel populations or increased investment in supplementary feeding. PMID:25338062

Influence of thinning of Douglas-fir forests on population parameters and diet of northern flying squirrels

USGS Publications Warehouse

Gomez, D.M.; Anthony, R.G.; Hayes, J.P.

2005-01-01

We investigated the effects of thinning young (35- to 45-yr-old) Douglas-fir (Pseudotsuga menziesii) forests on density, survival, body mass, movements, and diets of northern flying squirrels (Glaucomys sabrinus) in the northern coast range of Oregon. We used a repeated measures, randomized block design with 3 treatments (control, moderate thinning, and heavy thinning) and 4 replicates to study diets and population characteristics from 1994-1997. Densities of flying squirrels were variable in space and time, but they were positively correlated to biomass and frequency of fungal sporocarps, suggesting they were responding to food resources rather than forest structure. Fungal sporocarps comprised a major portion of the squirrel's diet, and other vegetative material made up the remainder of the diet. Several fungal genera including Gautieria, Geopora, Hymenogaster, Hysterangium, Melanogaster, and Rhizopogon were found more frequently in diets than on the trapping grids and therefore appeared to be selected by the squirrels. Flying squirrel movements were negatively correlated with the frequency of occurrence of fungal sporocarps at trap stations, suggesting that squirrels traveled greater distances to find fungal sporocarps where these food items were more sparsely distributed. We hypothesized that flying squirrel densities would be relatively low in these young, structurally simple forests; however, densities on some of the grids were >1.5 squirrels/ha, which was comparable to densities described for the species in late-successional forests. Our results indicated that commercial thinning did not have measurable short-term effects on density, survival, or body mass of flying squirrels.

Multiplex PCR assay discriminates rabbit, rat and squirrel meat in food chain.

PubMed

Ahamad, Mohammad Nasir Uddin; Ali, Md Eaqub; Hossain, M A Motalib; Asing, Asing; Sultana, Sharmin; Jahurul, M H A

2017-12-01

Rabbit meat is receiving increasing attention because it contains a high level of proteins with relatively little fat. On the other hand, squirrel meat is served in upper-class meals in certain countries, so is sold at higher prices. The other side of the coin is rat meat, which has family ties with rabbit and squirrel but poses substantial threats to public health because it is a potential carrier of several zoonotic organisms. Recently, rat meat was mislabelled and sold as lamb after chemical modification. Thus, the chances of rabbit and squirrel meat substitution by rat meat cannot be ruled out. For the first time, a multiplex PCR assay was developed in Malaysia for the discriminatory identification of rat, rabbit and squirrel in the food chain. Rabbit (123 bp), rat (108 bp) and squirrel (243 bp) targets were amplified from ATP6 and cytb genes, along with a eukaryotic internal control (141bp). The products were sequenced and cross-tested against 22 species. A total of 81 reference samples and 72 meatball specimens were screened to validate the assay. Analyte stability was evaluated through boiling, autoclaving and micro-oven cooking. The tested lower limits of detection were 0.01 ng DNA for pure meat and 0.1% for meatballs.

Fox Squirrels Match Food Assessment and Cache Effort to Value and Scarcity

PubMed Central

Delgado, Mikel M.; Nicholas, Molly; Petrie, Daniel J.; Jacobs, Lucia F.

2014-01-01

Scatter hoarders must allocate time to assess items for caching, and to carry and bury each cache. Such decisions should be driven by economic variables, such as the value of the individual food items, the scarcity of these items, competition for food items and risk of pilferage by conspecifics. The fox squirrel, an obligate scatter-hoarder, assesses cacheable food items using two overt movements, head flicks and paw manipulations. These behaviors allow an examination of squirrel decision processes when storing food for winter survival. We measured wild squirrels' time allocations and frequencies of assessment and investment behaviors during periods of food scarcity (summer) and abundance (fall), giving the squirrels a series of 15 items (alternating five hazelnuts and five peanuts). Assessment and investment per cache increased when resource value was higher (hazelnuts) or resources were scarcer (summer), but decreased as scarcity declined (end of sessions). This is the first study to show that assessment behaviors change in response to factors that indicate daily and seasonal resource abundance, and that these factors may interact in complex ways to affect food storing decisions. Food-storing tree squirrels may be a useful and important model species to understand the complex economic decisions made under natural conditions. PMID:24671221

Management and conservation of tree squirrels: the importance of endemism, species richness, and forest condition

Treesearch

John L. Koprowski

2005-01-01

Tree squirrels are excellent indicators of forest health yet the taxon is understudied. Most tree squirrels in the Holarctic Region are imperiled with some level of legal protection. The Madrean Archipelago is the epicenter for tree squirrel diversity in North America with 5 endemic species and 2 introduced species. Most species of the region are poorly studied in...

Effectiveness of flying squirrel excluder devices on red-cockaded woodpecker cavities

Treesearch

Susan C. Loeb

1996-01-01

The author tested the effectiveness of squirrel excluder devices (SQED?s) in deterring southern flying squirrels (Glaucomys volans) from using artificial red-cockaded woodpecker (Picoides borealis) cavities by placing them on approximately one-half of the cavities in 14 inactive recruitment clusters on the Savannah River Site, SC. SQED?s consisted of 2 pieces of 35.5-...

"Subpial Fan Cell" - A Class of Calretinin Neuron in Layer 1 of Adult Monkey Prefrontal Cortex.

PubMed

Gabbott, Paul L A

2016-01-01

Layer 1 of the cortex contains populations of neurochemically distinct neurons and afferent fibers which markedly affect neural activity in the apical dendritic tufts of pyramidal cells. Understanding the causal mechanisms requires knowledge of the cellular architecture and synaptic organization of layer 1. This study has identified eight morphological classes of calretinin immunopositive (CRet+) neurons (including Cajal-Retzius cells) in layer 1 of the prefrontal cortex (PFC) in adult monkey (Macaca fasicularis), with a distinct class - termed "subpial fan (SPF) cell" - described in detail. SPF cells were rare horizontal unipolar CRet+ cells located directly beneath the pia with a single thick primary dendrite that branched into a characteristic fan-like dendritic tree tangential to the pial surface. Dendrites had spines, filamentous processes and thorny branchlets. SPF cells lay millimeters apart with intralaminar axons that ramified widely in upper layer 1. Such cells were GABA immunonegative (-) and occurred in areas beyond PFC. Interspersed amidst SPF cells displaying normal structural integrity were degenerating CRet+ neurons (including SPF cells) and clumps of lipofuscin-rich cellular debris. The number of degenerating SPF cells increased during adulthood. Ultrastructural analyses indicated SPF cell somata received asymmetric (A - presumed excitatory) and symmetric (S - presumed inhibitory) synaptic contacts. Proximal dendritic shafts received mainly S-type and distal shafts mostly A-type input. All dendritic thorns and most dendritic spines received both synapse types. The tangential areal density of SPF cell axonal varicosities varied radially from parent somata - with dense clusters in more distal zones. All boutons formed A-type contacts with CRet- structures. The main post-synaptic targets were dendritic shafts (67%; mostly spine-bearing) and dendritic spines (24%). SPF-SPF cell innervation was not observed. Morphometry of SPF cells indicated a unique

Macroparasite fauna of alien grey squirrels (Sciurus carolinensis): composition, variability and implications for native species.

PubMed

Romeo, Claudia; Wauters, Lucas A; Ferrari, Nicola; Lanfranchi, Paolo; Martinoli, Adriano; Pisanu, Benoît; Preatoni, Damiano G; Saino, Nicola

2014-01-01

Introduced hosts populations may benefit of an "enemy release" through impoverishment of parasite communities made of both few imported species and few acquired local ones. Moreover, closely related competing native hosts can be affected by acquiring introduced taxa (spillover) and by increased transmission risk of native parasites (spillback). We determined the macroparasite fauna of invasive grey squirrels (Sciurus carolinensis) in Italy to detect any diversity loss, introduction of novel parasites or acquisition of local ones, and analysed variation in parasite burdens to identify factors that may increase transmission risk for native red squirrels (S. vulgaris). Based on 277 grey squirrels sampled from 7 populations characterised by different time scales in introduction events, we identified 7 gastro-intestinal helminths and 4 parasite arthropods. Parasite richness is lower than in grey squirrel's native range and independent from introduction time lags. The most common parasites are Nearctic nematodes Strongyloides robustus (prevalence: 56.6%) and Trichostrongylus calcaratus (6.5%), red squirrel flea Ceratophyllus sciurorum (26.0%) and Holarctic sucking louse Neohaematopinus sciuri (17.7%). All other parasites are European or cosmopolitan species with prevalence below 5%. S. robustus abundance is positively affected by host density and body mass, C. sciurorum abundance increases with host density and varies with seasons. Overall, we show that grey squirrels in Italy may benefit of an enemy release, and both spillback and spillover processes towards native red squirrels may occur.

Mandible shape and dwarfism in squirrels (Mammalia, Rodentia): interaction of allometry and adaptation

NASA Astrophysics Data System (ADS)

Hautier, Lionel; Fabre, Pierre-Henri; Michaux, Jacques

2009-06-01

Squirrels include several independent lineages of dwarf forms distributed into two ecological groups: the dwarf tree and flying squirrels. The mandible of dwarf tree squirrels share a highly reduced coronoid process and a condylar process drawn backwards. Dwarf flying squirrels on the other hand, have an elongated coronoid process and a well-differentiated condylar process. To interpret such a difference, Elliptic Fourier Transform was used to evaluate how mandible shape varies with dwarfism in sciurids. The results obtained show that this clear-cut difference cannot be explained by a simple allometric relationship in relation with size decrease. We concluded that the retention of anteriorly positioned eye sockets, in relation with distance estimation, allowed the conservation of a well-differentiated coronoid process in all flying species, despite the trend towards its reduction observed among sciurids as their size decreases.

Opportunistic predation by a broad-winged hawk on a southern flying squirrel

Treesearch

Daniel Saenz; Richard R. Schaefer

1995-01-01

Broad-winged Hawks (Buteo platypterus) take a wide variety of prey, including numerous small mammal species (Rusch and Doerr 1972; Fitch 1974; Mosher and Matray 1974; Rosenfield et al. 1984; and Toland 1986). Flying squirrels (Glaucomys spp.) are probably not regular prey of diurnal raptors due to the squirrel's nocturnal...

Behavioural correlates of urbanisation in the Cape ground squirrel Xerus inauris

NASA Astrophysics Data System (ADS)

Chapman, Tarryn; Rymer, Tasmin; Pillay, Neville

2012-11-01

Urbanisation critically threatens biodiversity because of habitat destruction and novel selection pressures. Some animals can respond to these challenges by modifying their behaviour, particularly anti-predator behaviour, allowing them to persist in heavily transformed urban areas. We investigated whether the anti-predator behaviour of the Cape ground squirrel Xerus inauris differed in three localities that differed in their level of urbanisation. According to the habituation hypothesis, we predicted that ground squirrels in urban areas would: (a) be less vigilant and forage more; (b) trade-off flight/vigilance in favour of foraging; and (c) have shorter flight initiation distances (FID) when approached by a human observer. Observations were made in winter and summer at each locality. As expected, ground squirrels in urbanised areas were less vigilant and had shorter FIDs but did not trade-off between foraging and vigilance. In contrast, a population in a non-urbanised locality showed greater levels of vigilance, FID and traded-off vigilance and foraging. A population in a peri-urban locality showed mixed responses. Our results indicate that Cape ground squirrels reduce their anti-predator behaviour in urban areas and demonstrate a flexible behavioural response to urbanisation.

Behavioural correlates of urbanisation in the Cape ground squirrel Xerus inauris.

PubMed

Chapman, Tarryn; Rymer, Tasmin; Pillay, Neville

2012-11-01

Urbanisation critically threatens biodiversity because of habitat destruction and novel selection pressures. Some animals can respond to these challenges by modifying their behaviour, particularly anti-predator behaviour, allowing them to persist in heavily transformed urban areas. We investigated whether the anti-predator behaviour of the Cape ground squirrel Xerus inauris differed in three localities that differed in their level of urbanisation. According to the habituation hypothesis, we predicted that ground squirrels in urban areas would: (a) be less vigilant and forage more; (b) trade-off flight/vigilance in favour of foraging; and (c) have shorter flight initiation distances (FID) when approached by a human observer. Observations were made in winter and summer at each locality. As expected, ground squirrels in urbanised areas were less vigilant and had shorter FIDs but did not trade-off between foraging and vigilance. In contrast, a population in a non-urbanised locality showed greater levels of vigilance, FID and traded-off vigilance and foraging. A population in a peri-urban locality showed mixed responses. Our results indicate that Cape ground squirrels reduce their anti-predator behaviour in urban areas and demonstrate a flexible behavioural response to urbanisation.

Does own experience affect perception of others' actions in capuchin monkeys (Cebus apella)?

PubMed

Kuroshima, Hika; Kaiser, Ingrid; Fragaszy, Dorothy M

2014-11-01

Anticipating another's actions is an important ability in social animals. Recent research suggests that in human adults and infants one's own action experience facilitates understanding and anticipation of others' actions. We investigated the link between first-person experience and perception of another's action in adult tufted capuchin monkeys (Sapajus apella spp., formerly Cebus apella spp.). In Experiment 1, the monkeys observed a familiar human (actor) trying to open a container using either a familiar or an unfamiliar action. They looked for longer when the actor tried to open the container using a familiar action. In Experiment 2, the actor performed two novel actions on a new container. The monkeys looked equally at the two actions. In Experiment 3, the monkeys were trained to open the container using one of the novel actions in Experiment 2. After training, we repeated the same procedure as in Experiment 2. The monkeys looked for longer when the actor manipulated the container using the action they had practiced than when she used the unfamiliar action. These results show that knowledge derived from one's own experience impacts perception of another's action in these New World monkeys.

Macroparasite Fauna of Alien Grey Squirrels (Sciurus carolinensis): Composition, Variability and Implications for Native Species

PubMed Central

Romeo, Claudia; Wauters, Lucas A.; Ferrari, Nicola; Lanfranchi, Paolo; Martinoli, Adriano; Pisanu, Benoît; Preatoni, Damiano G.; Saino, Nicola

2014-01-01

Introduced hosts populations may benefit of an "enemy release" through impoverishment of parasite communities made of both few imported species and few acquired local ones. Moreover, closely related competing native hosts can be affected by acquiring introduced taxa (spillover) and by increased transmission risk of native parasites (spillback). We determined the macroparasite fauna of invasive grey squirrels (Sciurus carolinensis) in Italy to detect any diversity loss, introduction of novel parasites or acquisition of local ones, and analysed variation in parasite burdens to identify factors that may increase transmission risk for native red squirrels (S. vulgaris). Based on 277 grey squirrels sampled from 7 populations characterised by different time scales in introduction events, we identified 7 gastro-intestinal helminths and 4 parasite arthropods. Parasite richness is lower than in grey squirrel's native range and independent from introduction time lags. The most common parasites are Nearctic nematodes Strongyloides robustus (prevalence: 56.6%) and Trichostrongylus calcaratus (6.5%), red squirrel flea Ceratophyllus sciurorum (26.0%) and Holarctic sucking louse Neohaematopinus sciuri (17.7%). All other parasites are European or cosmopolitan species with prevalence below 5%. S. robustus abundance is positively affected by host density and body mass, C. sciurorum abundance increases with host density and varies with seasons. Overall, we show that grey squirrels in Italy may benefit of an enemy release, and both spillback and spillover processes towards native red squirrels may occur. PMID:24505348

Evidence of autumn breeding in red squirrels, Tamiasciurus hudsonicus, in western Montana

Treesearch

Dean E. Pearson

2000-01-01

Red Squirrels (Tamiasciurus hudsonicus) routinely breed biannually in eastern North America, but normally breed once annually in western North America. However, a postpartum estrus resulting in two breeding seasons per year has been documented within the maritime region of British Columbia. I present two accounts of Red Squirrel behavior suggestive of autumn...

Monkey Visual Short-Term Memory Directly Compared to Humans

PubMed Central

Elmore, L. Caitlin; Wright, Anthony A.

2015-01-01

Two adult rhesus monkeys were trained to detect which item in an array of memory items had changed using the same stimuli, viewing times, and delays as used with humans. Although the monkeys were extensively trained, they were less accurate than humans with the same array sizes (2, 4, & 6 items), with both stimulus types (colored squares, clip art), and showed calculated memory capacities of about one item (or less). Nevertheless, the memory results from both monkeys and humans for both stimulus types were well characterized by the inverse power-law of display size. This characterization provides a simple and straightforward summary of a fundamental process of visual short-term memory (how VSTM declines with memory load) that emphasizes species similarities based upon similar functional relationships. By more closely matching of monkey testing parameters to those of humans, the similar functional relationships strengthen the evidence suggesting similar processes underlying monkey and human VSTM. PMID:25706544

Similarity of Bisphenol A Pharmacokinetics in Rhesus Monkeys and Mice: Relevance for Human Exposure

PubMed Central

Taylor, Julia A.; vom Saal, Frederick S.; Welshons, Wade V.; Drury, Bertram; Rottinghaus, George; Hunt, Patricia A.; Toutain, Pierre-Louis; Laffont, Céline M.; VandeVoort, Catherine A.

2011-01-01

Objective Daily adult human exposure to bisphenol A (BPA) has been estimated at < 1 μg/kg, with virtually complete first-pass conjugation in the liver in primates but not in mice. We measured unconjugated and conjugated BPA levels in serum from adult female rhesus monkeys and adult female mice after oral administration of BPA and compared findings in mice and monkeys with prior published data in women. Methods Eleven adult female rhesus macaques were fed 400 μg/kg deuterated BPA (dBPA) daily for 7 days. Levels of serum dBPA were analyzed by isotope-dilution liquid chromatography–mass spectrometry (0.2 ng/mL limit of quantitation) over 24 hr on day 1 and on day 7. The same dose of BPA was fed to adult female CD-1 mice; other female mice were administered 3H-BPA at doses ranging from 2 to 100,000 μg/kg. Results In monkeys, the maximum unconjugated serum dBPA concentration of 4 ng/mL was reached 1 hr after feeding and declined to low levels by 24 hr, with no significant bioaccumulation after seven daily doses. Mice and monkeys cleared unconjugated serum BPA at virtually identical rates. We observed a linear (proportional) relationship between administered dose and serum BPA in mice. Conclusions BPA pharmacokinetics in women, female monkeys, and mice is very similar. By comparison with approximately 2 ng/mL unconjugated serum BPA reported in multiple human studies, the average 24-hr unconjugated serum BPA concentration of 0.5 ng/mL in both monkeys and mice after a 400 μg/kg oral dose suggests that total daily human exposure is via multiple routes and is much higher than previously assumed. PMID:20855240

Will Arctic ground squirrels impede or accelerate climate-induced vegetation changes to the Arctic tundra?

NASA Astrophysics Data System (ADS)

Dalton, J.; Flower, C. E.; Brown, J.; Gonzalez-Meler, M. A.; Whelan, C.

2014-12-01

Considerable attention has been given to the climate feedbacks associated with predicted vegetation shifts in the Arctic tundra in response to global environmental change. However, little is known regarding the extent to which consumers can facilitate or respond to shrub expansion. Arctic ground squirrels, the largest and most northern ground squirrel, are abundant and widespread throughout the North American tundra. Their broad diet of seeds, flowers, herbage, bird's eggs and meat speaks to the need to breed, feed, and fatten in a span of some 12-16 weeks that separate their 8-9 month bouts of hibernation with the potential consequence to impact ecosystem dynamics. Therefore Arctic ground squirrels are a good candidate to evaluate whether consumers are mere responders (bottom-up effects) or drivers (top-down) of the observed and predicted vegetation changes. As a start towards this question, we measured the foraging intensity (giving-up densities) of Arctic ground squirrels in experimental food patches within which the squirrels experience diminishing returns as they seek the raisins and peanuts that we provided at the Toolik Lake field station in northern Alaska. If the squirrels show their highest feeding intensity in the shrubs, they may impede vegetation shifts by slowing the establishment and expansion of shrubs in the tundra. Conversely, if they show their lowest feeding intensity within shrub dominated areas, they may accelerate vegetation shifts. We found neither. Feeding intensity varied most among transects and times of day, and least along a tundra-to-shrub vegetation gradient. This suggests that the impacts of squirrels will be heterogeneous - in places responders and in others drivers. We should not be surprised then to see patches of accelerated and impeded vegetation changes in the tundra ecosystem. Some of these patterns may be predictable from the foraging behavior of Arctic ground squirrels.

FINITE-DIFFERENCE ELECTROMAGNETIC DEPOSITION/THERMOREGULATORY MODEL: COMPARISON BETWEEN THEORY AND MEASUREMENTS (JOURNAL VERSION)

EPA Science Inventory

The rate of the electromagnetic energy deposition and the resultant thermoregulatory response of a block model of a squirrel monkey exposed to plane-wave fields at 350 MHz were calculated using a finite-difference procedure. Noninvasive temperature measurements in live squirrel m...

Green foliage losses from ponderosa pines induced by Abert squirrels and snowstorms: A comparison. [Sciurus aberti; Pinus pondersosa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allred, W.S.; Gaud, W.S.

1993-01-01

Abert squirrels (Sciurus aberti) are obligate herbivores on ponderosa pine (Pinus ponderosa). The inner bark of pine shoots is considered one of the predominant food resources obtained by foraging squirrels. As squirrels forage for this resource they induce green needle losses from chosen feed trees. Amounts of induced green needle losses appear to vary according to the availability of alternative foods and squirrel population densities. Weather also induces green needle losses to ponderosa pines. Results of this study indicate that, at least in some years, heavy snowstorms can induce greater amounts of green needle losses than squirrels. Squirrel herbivory wasmore » not indicated as a factor in any tree mortality. However, losses due to snowstorms are more severe since they may cause the actual depletion of trees in the forest because of the tree mortality they inflict.« less

Habitat and Landscape Correlates of Southern Flying Squirrel Use of Red-Cockaded Woodpecker Clusters

Treesearch

Susan C. Loeb; Shawna L. Reid; Donald J. Lipscomb

2012-01-01

Southern flying squirrels (Glaucomys volans) can have significant negative impacts on redcockaded woodpecker (Picoides borealis) reproductive success and group size. Although direct control of southern flying squirrels may be necessary in small red-cockaded woodpecker populations (

The effects of gypsy moth infestation on gray squirrel habitat and populations

Treesearch

David E. Samuel; Rob Silvester

1991-01-01

The overall objective of this project was to determine the effects of defoliation on gray squirrel habitat. We will evaluate the existing Habitat Suitability Index (HSI) Model for gray squirrels on the University Forest and determine the effects of thinning on HSI values computed for thinned and unthinned stands. Habitat variables used in the U. S. Fish and Wildlife...

Causes of mortality and pathological lesions observed post-mortem in red squirrels (Sciurus vulgaris) in Great Britain

PubMed Central

2013-01-01

Background The red squirrel population in Great Britain has declined dramatically in recent decades, principally due to squirrelpox. Concern exists that red squirrels may become extinct nationally and, as there has been limited research in to diseases other than squirrelpox, this study aimed to identify additional causes of mortality. Results Post-mortem examinations on 163 red squirrels found dead on Isle of Wight (IoW) England, in Scotland and at other locations in Great Britain showed that 41.7% (n = 68) were killed by road traffic and 9.2% (n = 15) by predators, principally domestic cats and dogs. The overall male/female ratio was 1.08/1. Fleas were recorded on 34.9% of IoW squirrels and on 43.8% of Scottish squirrels but sucking lice and ixodid ticks were only seen on Scottish squirrels. Bacterial infections were significant, particularly in association with respiratory disease (n = 16); two squirrels died of Bordetella bronchiseptica bronchopneumonia. Cases of fatal exudative dermatitis (n = 5) associated with a lukM-positive clone of Staphylococcus aureus occurred only on the IoW. Toxoplasmosis (n = 12) was also confined to IoW where it was responsible for almost one tenth (9.5%) of all deaths. Hepatozoonosis was common, especially in IoW squirrels, but was not considered a primary cause of mortality. Hepatic capillariasis affected four IoW squirrels and one from Scotland. Fungal infections included oral candidiasis, adiaspiromycosis and pulmonary phaeohyphomycosis. Neoplastic conditions diagnosed were: pulmonary carcinoma, gastric spindle cell tumour, renal papillary adenoma and trichoepithelioma. Epidermal hyperplasia of unknown aetiology was seen in squirrels showing crusty lesions of the ear pinnae on IoW (n = 3) and Brownsea Island (n = 1), associated in two cases with cutaneous wart-like growths. Miscellaneous diagnoses included chylothorax, electrocution, intussusception, suspected cholecalciferol rodenticide poisoning and

Equivalence Between Squirrel Cage and Sheet Rotor Induction Motor

NASA Astrophysics Data System (ADS)

Dwivedi, Ankita; Singh, S. K.; Srivastava, R. K.

2016-06-01

Due to topological changes in dual stator induction motor and high cost of its fabrication, it is convenient to replace the squirrel cage rotor with a composite sheet rotor. For an experimental machine, the inner and outer stator stampings are normally available whereas the procurement of rotor stampings is quite cumbersome and is not always cost effective. In this paper, the equivalence between sheet/solid rotor induction motor and squirrel cage induction motor has been investigated using layer theory of electrical machines, so as to enable one to utilize sheet/solid rotor in dual port experimental machines.

Differential Estimates of Southern Flying Squirrel (Glaucomys volans) Population Structure Based on Capture Method.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laves, Kevin S.; Loeb, Susan C.

2006-01-01

ABSTRACT.—It is commonly assumed that population estimates derived from trapping small mammals are accurate and unbiased or that estimates derived from different capture methods are comparable. We captured southern flying squirrels (Glaucomys volans) using two methods to study their effect on red-cockaded woodpecker (Picoides borealis) reproductive success. Southern flying squirrels were captured at and removed from 30 red-cockaded woodpecker cluster sites during March to July 1994 and 1995 using Sherman traps placed in a grid encompassing a red-cockaded woodpecker nest tree and by hand from red-cockaded woodpecker cavities. Totals of 195 (1994) and 190 (1995) red-cockaded woodpecker cavities were examinedmore » at least three times each year. Trappability of southern flying squirrels in Sherman traps was significantly greater in 1995 (1.18%; 22,384 trap nights) than in 1994 (0.42%; 20,384 trap nights), and capture rate of southern flying squirrels in cavities was significantly greater in 1994 (22.7%; 502 cavity inspections) than in 1995 (10.8%; 555 cavity inspections). However, more southern flying squirrels were captured per cavity inspection than per Sherman trap night in both years. Male southern flying squirrels were more likely to be captured from cavities than in Sherman traps in 1994, but not in 1995. Both male and female juveniles were more likely to be captured in cavities than in traps in both years. In 1994 males in reproductive condition were more likely to be captured in cavities than in traps and in 1995 we captured significantly more reproductive females in cavities than in traps. Our data suggest that population estimates based solely on one trapping method may not represent true population size or structure of southern flying squirrels.« less

Influence of trap modifications and environmental predictors on capture success of southern flying squirrels

USGS Publications Warehouse

Jacques, Christopher N.; Zweep, James S.; Scheihing, Mary E.; Rechkemmer, Will T.; Jenkins, Sean E.; Klaver, Robert W.; Dubay, Shelli A.

2017-01-01

Sherman traps are the most commonly used live traps in studies of small mammals and have been successfully used in the capture of arboreal species such as the southern flying squirrel (Glaucomys volans). However, southern flying squirrels spend proportionately less time foraging on the ground, which necessitates above-ground trapping methods and modifications of capture protocols. Further, quantitative estimates of the factors affecting capture success of flying squirrel populations have focused solely on effects of trapping methodologies. We developed and evaluated the efficacy of a portable Sherman trap design for capturing southern flying squirrels during 2015–2016 at the Alice L. Kibbe Field Station, Illinois, USA. Additionally, we used logistic regression to quantify potential effects of time-dependent (e.g., weather) and time-independent (e.g., habitat, extrinsic) factors on capture success of southern flying squirrels. We recorded 165 capture events (119 F, 44 M, 2 unknown) using our modified Sherman trap design. Probability of capture success decreased 0.10/1° C increase in daily maximum temperature and by 0.09/unit increase (km/hr) in wind speed. Conversely, probability of capture success increased by 1.2/1° C increase in daily minimum temperature. The probability of capturing flying squirrels was negatively associated with trap orientation. When tree-mounted traps are required, our modified trap design is a safe, efficient, and cost-effective method of capturing animals when moderate weather (temp and wind speed) conditions prevail. Further, we believe that strategic placement of traps (e.g., northeast side of tree) and quantitative information on site-specific (e.g., trap location) characteristics (e.g., topographical features, slope, aspect, climatologic factors) could increase southern flying squirrel capture success. © 2017 The Wildlife Society.

Inaccessibility of reinforcement increases persistence and signaling behavior in the fox squirrel (Sciurus niger).

PubMed

Delgado, Mikel M; Jacobs, Lucia F

2016-05-01

Under natural conditions, wild animals encounter situations where previously rewarded actions do not lead to reinforcement. In the laboratory, a surprising omission of reinforcement induces behavioral and emotional responses described as frustration. Frustration can lead to aggressive behaviors and to the persistence of noneffective responses, but it may also lead to new behavioral responses to a problem, a potential adaptation. We assessed the responses to inaccessible reinforcement in free-ranging fox squirrels (Sciurus niger). We trained squirrels to open a box to obtain food reinforcement, a piece of walnut. After 9 training trials, squirrels were tested in 1 of 4 conditions: a control condition with the expected reward, an alternative reinforcement (a piece of dried corn), an empty box, or a locked box. We measured the presence of signals suggesting arousal (e.g., tail flags and tail twitches) and found that squirrels performed fewer of these behaviors in the control condition and increased certain behaviors (tail flags, biting box) in the locked box condition, compared to other experimental conditions. When faced with nonreinforcement, that is, frustration, squirrels increased the number of interactions with the apparatus and spent more time interacting with the apparatus. This study of frustration responses in a free-ranging animal extends the conclusions of captive studies to the field and demonstrates that fox squirrels show short-term negatively valenced responses to the inaccessibility, omission, and change of reinforcement. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Pulse register phonation in Diana monkey alarm calls

NASA Astrophysics Data System (ADS)

Riede, Tobias; Zuberbühler, Klaus

2003-05-01

The adult male Diana monkeys (Cercopithecus diana) produce predator-specific alarm calls in response to two of their predators, the crowned eagles and the leopards. The acoustic structure of these alarm calls is remarkable for a number of theoretical and empirical reasons. First, although pulsed phonation has been described in a variety of mammalian vocalizations, very little is known about the underlying production mechanism. Second, Diana monkey alarm calls are based almost exclusively on this vocal production mechanism to an extent that has never been documented in mammalian vocal behavior. Finally, the Diana monkeys' pulsed phonation strongly resembles the pulse register in human speech, where fundamental frequency is mainly controlled by subglottal pressure. Here, we report the results of a detailed acoustic analysis to investigate the production mechanism of Diana monkey alarm calls. Within calls, we found a positive correlation between the fundamental frequency and the pulse amplitude, suggesting that both humans and monkeys control fundamental frequency by subglottal pressure. While in humans pulsed phonation is usually considered pathological or artificial, male Diana monkeys rely exclusively on pulsed phonation, suggesting a functional adaptation. Moreover, we were unable to document any nonlinear phenomena, despite the fact that they occur frequently in the vocal repertoire of humans and nonhumans, further suggesting that the very robust Diana monkey pulse production mechanism has evolved for a particular functional purpose. We discuss the implications of these findings for the structural evolution of Diana monkey alarm calls and suggest that the restricted variability in fundamental frequency and robustness of the source signal gave rise to the formant patterns observed in Diana monkey alarm calls, used to convey predator information.

Characterization of Monkeypox virus infection in African rope squirrels (Funisciurus sp.)

USGS Publications Warehouse

Falendysz, Elizabeth; Lopera, Juan G.; Doty, Jeffrey B.; Nakazawa, Yoshinori J.; Crill, Colleen; Lorenzsonn, Faye; Kalemba, Lem's N.; Ronderos, Monica; Meija, Andres; Malekani, Jean M.; Karem, Kevin L.; Caroll, Darrin; Osorio, Jorge E.; Rocke, Tonie E.

2017-01-01

Monkeypox (MPX) is a zoonotic disease endemic in Central and West Africa and is caused by Monkeypox virus (MPXV), the most virulent Orthopoxvirus affecting humans since the eradication of Variola virus (VARV). Many aspects of the MPXV transmission cycle, including the natural host of the virus, remain unknown. African rope squirrels (Funisciurus spp.) are considered potential reservoirs of MPXV, as serosurveillance data in Central Africa has confirmed the circulation of the virus in these rodent species [1,2]. In order to understand the tissue tropism and clinical signs associated with infection with MPXV in these species, wild-caught rope squirrels were experimentally infected via intranasal and intradermal exposure with a recombinant MPXV strain from Central Africa engineered to express the luciferase gene. After infection, we monitored viral replication and shedding via in vivo bioluminescent imaging, viral culture and real time PCR. MPXV infection in African rope squirrels caused mortality and moderate to severe morbidity, with clinical signs including pox lesions in the skin, eyes, mouth and nose, dyspnea, and profuse nasal discharge. Both intranasal and intradermal exposures induced high levels of viremia, fast systemic spread, and long periods of viral shedding. Shedding and luminescence peaked at day 6 post infection and was still detectable after 15 days. Interestingly, one sentinel animal, housed in the same room but in a separate cage, also developed severe MPX disease and was euthanized. This study indicates that MPXV causes significant pathology in African rope squirrels and infected rope squirrels shed large quantities of virus, supporting their role as a potential source of MPXV transmission to humans and other animals in endemic MPX regions.

Characterization of Monkeypox virus infection in African rope squirrels (Funisciurus sp.).

PubMed

Falendysz, Elizabeth A; Lopera, Juan G; Doty, Jeffrey B; Nakazawa, Yoshinori; Crill, Colleen; Lorenzsonn, Faye; Kalemba, Lem's N; Ronderos, Monica D; Mejia, Andres; Malekani, Jean M; Karem, Kevin; Carroll, Darin S; Osorio, Jorge E; Rocke, Tonie E

2017-08-01

Monkeypox (MPX) is a zoonotic disease endemic in Central and West Africa and is caused by Monkeypox virus (MPXV), the most virulent Orthopoxvirus affecting humans since the eradication of Variola virus (VARV). Many aspects of the MPXV transmission cycle, including the natural host of the virus, remain unknown. African rope squirrels (Funisciurus spp.) are considered potential reservoirs of MPXV, as serosurveillance data in Central Africa has confirmed the circulation of the virus in these rodent species [1,2]. In order to understand the tissue tropism and clinical signs associated with infection with MPXV in these species, wild-caught rope squirrels were experimentally infected via intranasal and intradermal exposure with a recombinant MPXV strain from Central Africa engineered to express the luciferase gene. After infection, we monitored viral replication and shedding via in vivo bioluminescent imaging, viral culture and real time PCR. MPXV infection in African rope squirrels caused mortality and moderate to severe morbidity, with clinical signs including pox lesions in the skin, eyes, mouth and nose, dyspnea, and profuse nasal discharge. Both intranasal and intradermal exposures induced high levels of viremia, fast systemic spread, and long periods of viral shedding. Shedding and luminescence peaked at day 6 post infection and was still detectable after 15 days. Interestingly, one sentinel animal, housed in the same room but in a separate cage, also developed severe MPX disease and was euthanized. This study indicates that MPXV causes significant pathology in African rope squirrels and infected rope squirrels shed large quantities of virus, supporting their role as a potential source of MPXV transmission to humans and other animals in endemic MPX regions.

Role of gamma-aminobutyric acid type A (GABAA) receptor subtypes in acute benzodiazepine physical dependence-like effects: evidence from squirrel monkeys responding under a schedule of food presentation

PubMed Central

Fischer, Bradford D.; Teixeira, Laura P.; van Linn, Michael L.; Namjoshi, Ojas A.; Cook, James M.; Rowlett, James K.

2013-01-01

Rationale Assays of schedule-controlled responding can be used to characterize the pharmacology of benzodiazepines and other GABAA receptor modulators, and are sensitive to changes in drug effects that are related to physical dependence. Objective The present study used this approach to investigate the role of GABAA receptor subtypes in mediating dependence-like effects following benzodiazepine administration. Methods Squirrel monkeys (n=6) were trained on a fixed-ratio schedule of food reinforcement. Initially, the response rate-decreasing effects of chlordiazepoxide (0.1–10 mg/kg; nonselective GABAA receptor agonist), zolpidem (0.032–1.0 mg/kg; α1 subunit-containing GABAA subtype-preferring agonist) and HZ-166 (0.1–10 mg/kg; functionally selective α2 and α3 subunit-containing GABAA receptor agonist) were assessed. Next, acute dependence-like effects following single injections of chlordiazepoxide, zolpidem and HZ-166 were assessed with flumazenil (0.1–3.2 mg/kg; nonselective GABAA receptor antagonist). Finally, acute dependence-like effects following zolpidem administration were assessed with βCCt and 3-PBC (0.1–3.2 mg/kg and 0.32–10 mg/kg, respectively; α1 subunit-containing GABAA receptor antagonists). Results Chlordiazepoxide, zolpidem and HZ-166 produced dose- and time-dependent decreases in response rates, whereas flumazenil, βCCt and 3-PBC were ineffective. After the drug effects waned, flumazenil produced dose-dependent decreases in response rates following administration of 10 mg/kg chlordiazepoxide and 1.0 mg/kg zolpidem, but not following any dose of HZ-166. Further, both βCCt and 3-PBC produced dose-dependent decreases in response rates when administered after 1.0 mg/kg zolpidem. Conclusions These data raise the possibility that α1 subunit-containing GABAA receptors play a major role in physical dependence-related behaviors following a single injection of a benzodiazepine. PMID:23354533

Role of gamma-aminobutyric acid type A (GABAA) receptor subtypes in acute benzodiazepine physical dependence-like effects: evidence from squirrel monkeys responding under a schedule of food presentation.

PubMed

Fischer, Bradford D; Teixeira, Laura P; van Linn, Michael L; Namjoshi, Ojas A; Cook, James M; Rowlett, James K

2013-05-01

Assays of schedule-controlled responding can be used to characterize the pharmacology of benzodiazepines and other GABAA receptor modulators, and are sensitive to changes in drug effects that are related to physical dependence. The present study used this approach to investigate the role of GABAA receptor subtypes in mediating dependence-like effects following benzodiazepine administration. Squirrel monkeys (n = 6) were trained on a fixed-ratio schedule of food reinforcement. Initially, the response rate-decreasing effects of chlordiazepoxide (0.1-10 mg/kg; nonselective GABAA receptor agonist), zolpidem (0.032-1.0 mg/kg; α1 subunit-containing GABAA subtype-preferring agonist), and HZ-166 (0.1-10 mg/kg; functionally selective α2 and α3 subunit-containing GABAA receptor agonist) were assessed. Next, acute dependence-like effects following single injections of chlordiazepoxide, zolpidem, and HZ-166 were assessed with flumazenil (0.1-3.2 mg/kg; nonselective GABAA receptor antagonist). Finally, acute dependence-like effects following zolpidem administration were assessed with βCCt and 3-PBC (0.1-3.2 mg/kg and 0.32-10 mg/kg, respectively; α1 subunit-containing GABAA receptor antagonists). Chlordiazepoxide, zolpidem, and HZ-166 produced dose- and time-dependent decreases in response rates, whereas flumazenil, βCCT, and 3-PBC were ineffective. After the drug effects waned, flumazenil produced dose-dependent decreases in response rates following administration of 10 mg/kg chlordiazepoxide and 1.0 mg/kg zolpidem, but not following any dose of HZ-166. Further, both βCCT and 3-PBC produced dose-dependent decreases in response rates when administered after 1.0 mg/kg zolpidem. These data raise the possibility that α1 subunit-containing GABAA receptors play a major role in physical dependence-related behaviors following a single injection of a benzodiazepine.

Monochromatic ocular wave aberrations in young monkeys

PubMed Central

Ramamirtham, Ramkumar; Kee, Chea-su; Hung, Li-Fang; Qiao-Grider, Ying; Roorda, Austin; Smith, Earl L.

2006-01-01

High-order monochromatic aberrations could potentially influence vision-dependent refractive development in a variety of ways. As a first step in understanding the effects of wave aberration on refractive development, we characterized the maturational changes that take place in the high-order aberrations of infant rhesus monkey eyes. Specifically, we compared the monochromatic wave aberrations of infant and adolescent animals and measured the longitudinal changes in the high-order aberrations of infant monkeys during the early period when emmetropization takes place. Our main findings were that (1) adolescent monkey eyes have excellent optical quality, exhibiting total RMS errors that were slightly better than those for adult human eyes that have the same numerical aperture and (2) shortly after birth, infant rhesus monkeys exhibited relatively larger magnitudes of high-order aberrations predominately spherical aberration, coma, and trefoil, which decreased rapidly to assume adolescent values by about 200 days of age. The results demonstrate that rhesus monkey eyes are a good model for studying the contribution of individual ocular components to the eye’s overall aberration structure, the mechanisms responsible for the improvements in optical quality that occur during early ocular development, and the effects of high-order aberrations on ocular growth and emmetropization. PMID:16750549

Demographic and behavioral responses of southern flying squirrels to experimental logging in Arkansas

Treesearch

James F. Taulman; Kimberly G. Smith; Ronald E. Thill

1998-01-01

This study investigated responses of populations of southern flying squirrels to a range of experimental even-aged and uneven-aged timber-harvest practices along a gradient of increasing disturbance intensity. The goals were to determine whether measurable demographic parameters of squirrels in experimental forests would change after logging; whether a disturbance...

Forest habitat associations of the golden-mantled ground squirrel: Implications for fuels management

Treesearch

Katharine R. Shick; Dean E. Pearson; Leonard F. Ruggiero

2006-01-01

Golden-mantled ground squirrels are commonly associated with high-elevation habitats near or above upper timberline. This species also occurs in fire-adapted, low-elevation forests that are targeted for forest health restoration (FHR) treatments intended to remove encroaching understory trees and thin overstory trees. Hence, the golden-mantled ground squirrel...

Locomotor performance and cost of transport in the northern flying squirrel Glaucomys sabrinus.

Treesearch

John S. Scheibe; Winston P. Smith; Jill Bassham; Dawn Magness

2006-01-01

We assess locomotor performance by northern flying squirrels Glartcontys sabrinus Shaw, 1801 and test the hypothesis that gliding locomotion is energetically cheaper than quadrupedal locomotion. We measured 168 glides by 82 northern flying squirrels in Alaska. Mean glide distances varied from 12.46 m to 14.39 m, with a maximum observed glide...

A Purkinje shift in the spectral sensitivity of grey squirrels

PubMed Central

Silver, Priscilla H.

1966-01-01

1. The light-adapted spectral sensitivity of the grey squirrel has been determined by an automated training method at a level about 6 log units above the squirrel's absolute threshold. 2. The maximum sensitivity is near 555 nm, under light-adapted conditions, compared with the dark-adapted maximum near 500 nm found by a similar method. 3. Neither the light-adapted nor the dark-adapted behavioural threshold agrees with electrophysiological findings using single flash techniques, but there is agreement with e.r.g. results obtained with sinusoidal stimuli. PMID:5972118

Macroparasite community of the Eurasian red squirrel (Sciurus vulgaris): poor species richness and diversity.

PubMed

Romeo, Claudia; Pisanu, Benoît; Ferrari, Nicola; Basset, Franck; Tillon, Laurent; Wauters, Lucas A; Martinoli, Adriano; Saino, Nicola; Chapuis, Jean-Louis

2013-10-01

The Eurasian red squirrel (Sciurus vulgaris) is the only naturally occurring tree squirrel throughout its range. We aim at improving current knowledge on its macroparasite fauna, expecting that it will have a poor parasite diversity because in species that have no sympatric congeners parasite richness should be lower than in hosts sharing their range with several closely related species, where host-switching events and lateral transmission are promoted. We examined gastro-intestinal helminth and ectoparasite communities (excluding mites) of, respectively, 147 and 311 red squirrel roadkills collected in four biogeographic regions in Italy and France. As expected, the macroparasite fauna was poor: we found five species of nematodes and some unidentified cestodes, three fleas, two sucking lice and two hard ticks. The helminth community was dominated by a single species, the oxyurid Trypanoxyuris (Rodentoxyuris) sciuri (prevalence, 87%; mean abundance, 373 ± 65 worms/host). Its abundance varied among seasons and biogeographic regions and increased with body mass in male hosts while decreased in females. The most prevalent ectoparasites were the flea Ceratophyllus (Monopsyllus) sciurorum (28%), whose presence was affected by season, and the generalist tick Ixodes (Ixodes) ricinus that was found only in France (34%). All the other helminths and arthropod species were rare, with prevalence below 10%. However, the first record of Strongyloides robustus, a common nematode of North American Eastern grey squirrels (S. carolinensis), in two red squirrels living in areas where this alien species co-inhabits, deserves further attention, since low parasite richness could result in native red squirrels being particularly vulnerable to parasite spillover.

Weak orientation and direction selectivity in lateral geniculate nucleus representing central vision in the gray squirrel Sciurus carolinensis

PubMed Central

Zaltsman, Julia B.; Heimel, J. Alexander

2015-01-01

Classic studies of lateral geniculate nucleus (LGN) and visual cortex (V1) in carnivores and primates have found that a majority of neurons in LGN exhibit a center-surround organization, while V1 neurons exhibit strong orientation selectivity and, in many species, direction selectivity. Recent work in the mouse and the monkey has discovered previously unknown classes of orientation- and direction-selective neurons in LGN. Furthermore, some recent studies in the mouse report that many LGN cells exhibit pronounced orientation biases that are of comparable strength to the subthreshold inputs to V1 neurons. These results raise the possibility that, in rodents, orientation biases of individual LGN cells make a substantial contribution to cortical orientation selectivity. Alternatively, the size and contribution of orientation- or direction-selective channels from LGN to V1 may vary across mammals. To address this question, we examined orientation and direction selectivity in LGN and V1 neurons of a highly visual diurnal rodent: the gray squirrel. In the representation of central vision, only a few LGN neurons exhibited strong orientation or direction selectivity. Across the population, LGN neurons showed weak orientation biases and were much less selective for orientation compared with V1 neurons. Although direction selectivity was weak overall, LGN layers 3abc, which contain neurons that express calbindin, exhibited elevated direction selectivity index values compared with LGN layers 1 and 2. These results suggest that, for central visual fields, the contribution of orientation- and direction-selective channels from the LGN to V1 is small in the squirrel. As in other mammals, this small contribution is elevated in the calbindin-positive layers of the LGN PMID:25717157

Cluster of sylvatic epidemic typhus cases associated with flying squirrels, 2004-2006.

PubMed

Chapman, Alice S; Swerdlow, David L; Dato, Virginia M; Anderson, Alicia D; Moodie, Claire E; Marriott, Chandra; Amman, Brian; Hennessey, Morgan; Fox, Perry; Green, Douglas B; Pegg, Eric; Nicholson, William L; Eremeeva, Marina E; Dasch, Gregory A

2009-07-01

In February 2006, a diagnosis of sylvatic epidemic typhus in a counselor at a wilderness camp in Pennsylvania prompted a retrospective investigation. From January 2004 through January 2006, 3 more cases were identified. All had been counselors at the camp and had experienced febrile illness with myalgia, chills, and sweats; 2 had been hospitalized. All patients had slept in the same cabin and reported having seen and heard flying squirrels inside the wall adjacent to their bed. Serum from each patient had evidence of infection with Rickettsia prowazekii. Analysis of blood and tissue from 14 southern flying squirrels trapped in the woodlands around the cabin indicated that 71% were infected with R. prowazekii. Education and control measures to exclude flying squirrels from housing are essential to reduce the likelihood of sylvatic epidemic typhus.

Early Rockets

NASA Image and Video Library

1959-05-18

A squirrel monkey, Able, is being ready for placement into a capsule for a preflight test of Jupiter, AM-18 mission. AM-18 was launched on May 28, 1959 and also carried a rhesus monkey, Baker, into suborbit.

“Subpial Fan Cell” — A Class of Calretinin Neuron in Layer 1 of Adult Monkey Prefrontal Cortex

PubMed Central

Gabbott, Paul L. A.

2016-01-01

Layer 1 of the cortex contains populations of neurochemically distinct neurons and afferent fibers which markedly affect neural activity in the apical dendritic tufts of pyramidal cells. Understanding the causal mechanisms requires knowledge of the cellular architecture and synaptic organization of layer 1. This study has identified eight morphological classes of calretinin immunopositive (CRet+) neurons (including Cajal-Retzius cells) in layer 1 of the prefrontal cortex (PFC) in adult monkey (Macaca fasicularis), with a distinct class — termed “subpial fan (SPF) cell” — described in detail. SPF cells were rare horizontal unipolar CRet+ cells located directly beneath the pia with a single thick primary dendrite that branched into a characteristic fan-like dendritic tree tangential to the pial surface. Dendrites had spines, filamentous processes and thorny branchlets. SPF cells lay millimeters apart with intralaminar axons that ramified widely in upper layer 1. Such cells were GABA immunonegative (-) and occurred in areas beyond PFC. Interspersed amidst SPF cells displaying normal structural integrity were degenerating CRet+ neurons (including SPF cells) and clumps of lipofuscin-rich cellular debris. The number of degenerating SPF cells increased during adulthood. Ultrastructural analyses indicated SPF cell somata received asymmetric (A — presumed excitatory) and symmetric (S — presumed inhibitory) synaptic contacts. Proximal dendritic shafts received mainly S-type and distal shafts mostly A-type input. All dendritic thorns and most dendritic spines received both synapse types. The tangential areal density of SPF cell axonal varicosities varied radially from parent somata — with dense clusters in more distal zones. All boutons formed A-type contacts with CRet- structures. The main post-synaptic targets were dendritic shafts (67%; mostly spine-bearing) and dendritic spines (24%). SPF-SPF cell innervation was not observed. Morphometry of SPF cells

Modelling recolonization of second-growth forest stands by the north american red squirrel Tamiasciurus hudsonicus.

PubMed

Nyquist, B; Tyson, R; Larsen, K

2007-05-01

In this paper, we present a model for source-sink population dynamics where the locations of source and sink habitats change over time. We do this in the context of the population dynamics of the North American red squirrel, Tamiasciurus hudsonicus, within a forest environment subject to harvesting and regrowth. Harvested patches of forest are initially sinks, then eventually become source habitat again as the forest regrows. At the same time, each harvested patch is gradually recolonized by squirrels from other forest patches. We are interested in the interaction of forest harvesting dynamics with squirrel population dynamics. This depends on the harvesting schedule, and on the choices squirrels make when deciding whether to settle in a mature forest patch or in a recently harvested patch. We find that the time it takes for a second-growth forest patch to be recolonized at the mature forest level is longer than the time required for the habitat quality to be restored to the mature forest level. We also notice that recolonization pressure decreases squirrel populations in neighbouring patches. The connectivity between forest patches and the cutting schedule used also affect the time course of recolonization and steady-state population levels.

Detection of Signal Regulatory Protein α in Saimiri sciureus (Squirrel Monkey) by Anti-Human Monoclonal Antibody

PubMed Central

de Souza, Hugo Amorim dos Santos; Costa-Correa, Edmar Henrique; Bianco-Junior, Cesare; Andrade, Márcia Cristina Ribeiro; Lima-Junior, Josué da Costa; Pratt-Riccio, Lilian Rose; Daniel-Ribeiro, Cláudio Tadeu; Totino, Paulo Renato Rivas

2017-01-01

Non-human primates (NHP) are suitable models for studying different aspects of the human system, including pathogenesis and protective immunity to many diseases. However, the lack of specific immunological reagents for neo-tropical monkeys, such as Saimiri sciureus, is still a major factor limiting studies in these models. An alternative strategy to circumvent this obstacle has been the selection of immunological reagents directed to humans, which present cross-reactivity with NHP molecules. In this context and considering the key role of inhibitory immunoreceptors—such as the signal regulatory protein α (SIRPα)—in the regulation of immune responses, in the present study, we attempted to evaluate the ability of anti-human SIRPα monoclonal antibodies to recognize SIRPα in antigen-presenting S. sciureus peripheral blood mononuclear cells (PBMC). As shown by flow cytometry analysis, the profile of anti-SIRPα staining as well as the levels of SIRPα-positive cells in PBMC from S. sciureus were similar to those observed in human PBMC. Furthermore, using anti-SIRPα monoclonal antibody, it was possible to detect a decrease of the SIRPα levels on surface of S. sciureus cells after in vitro stimulation with lipopolysaccharides. Finally, using computed-based analysis, we observed a high degree of conservation of SIRPα across six species of primates and the presence of shared epitopes in the extracellular domain between humans and Saimiri genus that could be targeted by antibodies. In conclusion, we have identified a commercially available anti-human monoclonal antibody that is able to detect SIRPα of S. sciureus monkeys and that, therefore, can facilitate the study of the immunomodulatory role of SIRPα when S. sciureus is used as a model. PMID:29312325

Spider monkeys (Ateles geoffroyi) are less sensitive to the odor of aliphatic ketones than to the odor of other classes of aliphatic compounds.

PubMed

Eliasson, Moa; Hernandez Salazar, Laura Teresa; Laska, Matthias

2015-10-01

Aliphatic ketones are widely present in body-borne and food odors of primates. Therefore, we used an operant conditioning paradigm and determined olfactory detection thresholds in four spider monkeys for a homologous series of aliphatic 2-ketones (2-butanone to 2-nonanone) and two of their isomers (3- and 4-heptanone). We found that, with the exception of the two shortest-chained ketones, all animals detected concentrations <1 ppm (parts per million), and with five odorants individual animals even reached threshold values <0.1 ppm. Further, we found a significant correlation between olfactory sensitivity of the spider monkeys and carbon chain length of the 2-ketones which can best be described as a U-shaped function. In contrast, no significant correlation was found between olfactory sensitivity and position of the functional carbonyl group. Across-odorant and across-species comparisons revealed the following: spider monkeys are significantly less sensitive to the odors of aliphatic ketones than to the odor of other classes of aliphatic compounds (1-alcohols, n-aldehydes, n-acetic esters, and n-carboxylic acids) sharing the same carbon length. Spider monkeys do not differ significantly in their olfactory sensitivity for aliphatic ketones from squirrel monkeys and pigtail macaques, but are significantly less sensitive to these odorants compared to human subjects and mice. These findings support the notion that neuroanatomical and genetic properties do not allow for reliable predictions with regard to a species' olfactory sensitivity. Further, we conclude that the frequency of occurrence of a class of odorants in a species' chemical environment does not allow for reliable predictions of the species' olfactory sensitivity. Copyright © 2015 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Stereological assessment of normal Persian squirrels (Sciurus anomalus) kidney.

PubMed

Akbari, Mohsen; Goodarzi, Nader; Tavafi, Majid

2017-03-01

The functions of the mammalian kidney are closely related to its structure. This suggests that renal function can be completely characterized by accurate knowledge of its quantitative morphological features. The aim of this study was to investigate the histomorphometric features of the kidney using design-based and unbiased stereological methods in the Persian squirrel (Sciurus anomalus), which is the only representative of the Sciuridae family in the Middle East. The left kidneys of five animals were examined. Total volume of the kidney, cortex, and medulla were determined to be 960.75 ± 87.4, 754.31 ± 77.09 and 206.1 ± 16.89 mm 3 , respectively. The glomerular number was 32844.03 ± 1069.19, and the total glomerular volume was estimated to be 36.7 ± 1.45 mm 3 . The volume and length of the proximal convoluted tubule were estimated at 585.67 ± 60.7 mm 3 and 328.8 ± 14.8 m, respectively, with both values being greater than those reported in the rat kidney. The volume and length of the distal convoluted tubule were calculated at 122.34 ± 7.38 mm 3 and 234.4 ± 17.45 m, respectively, which are also greater than those reported in the rat kidney. Despite the comparable body weight, the total number and mean individual volume of glomeruli in the Persian squirrel kidney were greater than those in the rat kidney. Overall, the stereological variables of the kidneys elucidated in this study are exclusive to the Persian squirrel. Our findings, together with future renal physiological data, will contribute to a better understanding of the renal structure-function relationship in the Persian squirrel.

No safety in the trees: Local and species-level adaptation of an arboreal squirrel to the venom of sympatric rattlesnakes.

PubMed

Pomento, Abby M; Perry, Blair W; Denton, Robert D; Gibbs, H Lisle; Holding, Matthew L

2016-08-01

Within some species, squirrels respond to variable selection from venomous snake predators by showing population-level variation in resistance, while between species, some rattlesnakes possess venom that is more effective at overcoming venom resistance in different species of squirrels. A functional evaluation of resistance variation to venom within and between species of squirrels and snakes can link resistance variation to its evolutionary causes across these different evolutionary scales. To do this, we compared the effectiveness of squirrel sera in inhibiting rattlesnake (Crotalus spp.) venom metalloproteinase activity between populations and between species to test for a response to local variation in selection from a single rattlesnake predator and for specialization of two resistant squirrel species to each of their distinct sympatric snake predators. We found that Timber Rattlesnake (Crotalus horridus) venom inhibition by Eastern gray squirrels (Sciurus carolinensis) is higher at a site where the rattlesnakes are present, which suggests selection may maintain venom resistance in populations separated by short distances. Next, we performed a reciprocal cross of venoms and sera from two rattlesnake and two squirrel species. This showed that squirrel resistance is lower when tested against venom from allopatric compared to sympatric rattlesnake species, demonstrating that squirrel inhibitors are specialized to sympatric venom and suggesting a tradeoff in terms of specialization to the venom of a specific species of rattlesnake predator. This pattern can be explained if inhibitors must recognize venom proteins and resistance evolution tracks venom evolution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Diet affects arctic ground squirrel gut microbial metatranscriptome independent of community structure

PubMed Central

Hatton, Jasmine J.; Stevenson, Timothy J.; Buck, C. Loren; Duddleston, Khrystyne N.

2017-01-01

Summary We examined the effect of diet on pre-hibernation fattening and the gut microbiota of captive arctic ground squirrels (Urocitellus parryii). We measured body composition across time and gut microbiota density, diversity, and function prior to and after five-weeks on control, high-fat, low-fat (18%, 40%, and 10% energy from fat, respectively), or restricted calorie (50% of control) diets. Squirrels fattened at the same rate and to the same degree on all diets. Additionally, we found no differences in gut microbiota diversity or short chain fatty acid production across time or with diet. Analysis of the gut microbial transcriptome indicated differences in community function among diet groups, but not across time, and revealed shifts in the relative contribution of function at a taxonomic level. Our results demonstrate that pre-hibernation fattening of arctic ground squirrels is robust to changes in diet and is accomplished by more than increased food intake. Although our analyses did not uncover a definitive link between host fattening and the gut microbiota, and suggest the squirrels may possess a gut microbial community structure that is unresponsive to dietary changes, studies manipulating diet earlier in the active season may yet uncover a relationship between host diet, fattening and gut microbiota. PMID:28251799

Early Life Experiences and Telomere Length in Adult Rhesus Monkeys: An Exploratory Study

PubMed Central

Schneper, Lisa M.; Brooks-Gunn, Jeanne; Notterman, Daniel A.; Suomi, Stephen J.

2016-01-01

Objective Child rearing environments have been associated with morbidity in adult rhesus monkeys. We examine whether such links are also seen with leukocyte telomere length. Methods To determine telomere length in leukocytes, blood was collected from 11 adult females aged seven to ten years who had been exposed to different rearing environments between birth and seven months. Four had been reared with their mothers in typical social groups comprised of other females, their offspring, and 1–2 adult males. The other seven had been reared in either small groups of peers or in individual cages with extensive peer interaction daily. After seven months, all shared a common environment. Results Telomere lengths were longer for those adults who had been reared with their mothers in social groups (median = 16.0 kb, interquartile range = 16.5–15.4) than for those who were reared without their mothers (median = 14.0 kb, interquartile range = 14.3–12.7; 2.2 kb/telomere difference, p<0.027). Conclusions This observation adds to emerging knowledge about early adverse child rearing conditions and their potential for influencing later morbidity. As newborns were randomly assigned to the mother or other rearing conditions, the findings are not confounded by other conditions that co-occur with adverse child rearing environments in humans (e.g., prenatal stress, nutrition and health as well as postnatal nutrition and negative life experiences over and above rearing conditions). PMID:27763985

Ecology of northern flying squirrels: implications for ecosystem management in the Pacific Northwest, USA.

Treesearch

Andrew B. Carey

2002-01-01

Northern flying squirrels (Glaucomys sabrinus) in the USA Pacific Northwest are keystone species that disseminate the spores of ectomycorrhizal fungi symbiotic with Pinaceae and that are preyed upon by a variety of vertebrate predators. Substantial research has shown that these squirrels tend to be most abundant in naturally regenerated forests...

Depth perception from moving cast shadow in macaque monkey.

PubMed

Mizutani, Saneyuki; Usui, Nobuo; Yokota, Takanori; Mizusawa, Hidehiro; Taira, Masato; Katsuyama, Narumi

2015-07-15

In the present study, we investigate whether the macaque monkey can perceive motion in depth using a moving cast shadow. To accomplish this, we conducted two experiments. In the first experiment, an adult Japanese monkey was trained in a motion discrimination task in depth by binocular disparity. A square was presented on the display so that it appeared with a binocular disparity of 0.12 degrees (initial position), and moved toward (approaching) or away from (receding) the monkey for 1s. The monkey was trained to discriminate the approaching and receding motion of the square by GO/delayed GO-type responses. The monkey showed a significantly high accuracy rate in the task, and the performance was maintained when the position, color, and shape of the moving object were changed. In the next experiment, the change in the disparity was gradually decreased in the motion discrimination task. The results showed that the performance of the monkey declined as the distance of the approaching and receding motion of the square decreased from the initial position. However, when a moving cast shadow was added to the stimulus, the monkey responded to the motion in depth induced by the cast shadow in the same way as by binocular disparity; the reward was delivered randomly or given in all trials to prevent the learning of the 2D motion of the shadow in the frontal plane. These results suggest that the macaque monkey can perceive motion in depth using a moving cast shadow as well as using binocular disparity. Copyright © 2015 Elsevier B.V. All rights reserved.

Sertraline inhibits increases in body fat and carbohydrate dysregulation in adult female cynomolgus monkeys

PubMed Central

Silverstein-Metzler, Marnie G.; Shively, Carol A.; Clarkson, Thomas B.; Appt, Susan E.; Carr, J.Jeffrey; Kritchevsky, Stephen B.; Jones, Sara R.; Register, Thomas C.

2017-01-01

Selective serotonin reuptake inhibitor (SSRI) antidepressants are widely prescribed for depression and other disorders. SSRIs have become one of the most commonly used drugs in the United States, particularly by women. Acute effects on body composition and carbohydrate metabolism have been reported, but little is known regarding the effects of chronic SSRI use. We evaluated the effects of chronic administration of a commonly prescribed SSRI, sertraline HCl, on body weight and composition, fat distribution, carbohydrate metabolism, as well as activity, in adult female depressed and nondepressed cynomolgus monkeys (Macaca fascicularis; n = 42) using a placebo-controlled, longitudinal, randomized study design. Phenotypes were evaluated prior to and after 18 months of oral sertraline (20 mg/kg) or placebo. Over the 18 month treatment period, the placebo group experienced increases in body weight, body fat (visceral and subcutaneous) fasting insulin concentrations, and homeostasis model assessment of insulin resistance scores (HOMA-IR). Sertraline treatment prevented increases in body weight, fat, insulin, and HOMA-IR (all p < 0.05), without significantly altering activity levels. Sertraline treatment altered adiponectin in an unusual way — reducing circulating adiponectin in depressed monkeys without affecting fat mass or body weight. Deleterious effects on adiponectin, a potentially insulin-sensitizing and atheroprotective protein, may result in adverse effects on cardiovascular health despite otherwise beneficial effects on body composition and carbohydrate metabolism. PMID:26939086

The effect of age on the discriminative stimulus effects of ethanol and its GABA(A) receptor mediation in cynomolgus monkeys.

PubMed

Helms, Christa M; Grant, Kathleen A

2011-08-01

Excessive alcohol consumption is less common among aged compared to young adults, with aged adults showing greater sensitivity to many behavioral effects of ethanol. This study compared the discriminative stimulus effects of ethanol in young and middle-aged adult cynomolgus monkeys (Macaca fascicularis) and its γ-aminobutyric acid (GABA)(A) receptor mediation. Two male and two female monkeys trained to discriminate ethanol (1.0 g/kg, i.g.; 60-min pre-treatment interval) from water at 5-6 years of age (Grant et al. in Psychopharmacology 152:181-188, 2000) were re-trained in the current study more than a decade later (19.3 ± 1.0 years of age) for a within-subjects comparison. Also, four experimentally naïve middle-aged (mean ± SEM, 17.0 ± 1.5 years of age) female monkeys were trained to discriminate ethanol for between-subjects comparison with published data from young adult naïve monkeys. Two of the naïve middle-aged monkeys attained criterion performance, with weak stimulus control and few discrimination tests, despite greater blood-ethanol concentration 60 min after 1.0 g/kg ethanol in middle-aged compared to young adult female monkeys (Green et al. in Alcohol Clin Exp Res 23:611-616, 1999). The efficacy of the GABA(A) receptor positive modulators pentobarbital, midazolam, allopregnanolone, pregnanolone, and androsterone to substitute for the discriminative stimulus effects of 1.0 g/kg ethanol was maintained from young adulthood to middle age. The data suggest that 1.0 g/kg ethanol is a weak discriminative stimulus in naive middle-aged monkeys. Nevertheless, the GABA(A) receptor mechanisms mediating the discriminative stimulus effects of ethanol, when learned as a young adult, appear stable across one third of the primate lifespan.

Ectoparasites and fitness of female Columbian ground squirrels

PubMed Central

Raveh, Shirley; Neuhaus, Peter; Dobson, F. Stephen

2015-01-01

Parasites play an important role in the evolution of host traits via natural selection, coevolution and sexually selected ornaments used in mate choice. These evolutionary scenarios assume fitness costs for hosts. To test this assumption, we conducted an ectoparasite removal experiment in free-living Columbian ground squirrels (Urocittelus columbianus) in four populations over three years. Adult females were randomly chosen to be either experimentally treated with anti-parasite treatments (spot-on solution and flea powder, N = 61) or a sham treatment (control, N = 44). We expected that experimental females would show better body condition, increased reproductive success and enhanced survival. Contrary to our expectations, body mass was not significantly different between treatments at mating, birth of litter or weaning of young. Further, neither number nor size of young at weaning differed significantly between the two treatments. Survival to the next spring for adult females and juveniles was not significantly different between experimental and control treatments. Finally, annual fitness was not affected by the treatments. We concluded that females and their offspring were able compensate for the presence of ectoparasites, suggesting little or no fitness costs of parasites for females in the different colonies and during the years of our experiments. PMID:25870399

A meta-analysis of forest age and structure effects on northern flying squirrel densities

Treesearch

Gillian L. Holloway; Winston P. Smith

2011-01-01

Research on the impact of clearcut logging and partial harvesting practices on northern flying squirrels (Glaucomys sabrinus) has shown inconsistent and contrary results, limiting the use of this species as a management indicator species. Much of this variability in study results is due to the labor intensive nature of studying flying squirrels,...

Melanocortin 1 receptor (MC1R) gene sequence variation and melanism in the gray (Sciurus carolinensis), fox (Sciurus niger), and red (Sciurus vulgaris) squirrel.

PubMed

McRobie, Helen R; King, Linda M; Fanutti, Cristina; Coussons, Peter J; Moncrief, Nancy D; Thomas, Alison P M

2014-01-01

Sequence variations in the melanocortin 1 receptor (MC1R) gene are associated with melanism in many different species of mammals, birds, and reptiles. The gray squirrel (Sciurus carolinensis), found in the British Isles, was introduced from North America in the late 19th century. Melanism in the British gray squirrel is associated with a 24-bp deletion in the MC1R. To investigate the origin of this mutation, we sequenced the MC1R of 95 individuals including 44 melanic gray squirrels from both the British Isles and North America. Melanic gray squirrels of both populations had the same 24-bp deletion associated with melanism. Given the significant deletion associated with melanism in the gray squirrel, we sequenced the MC1R of both wild-type and melanic fox squirrels (Sciurus niger) (9 individuals) and red squirrels (Sciurus vulgaris) (39 individuals). Unlike the gray squirrel, no association between sequence variation in the MC1R and melanism was found in these 2 species. We conclude that the melanic gray squirrel found in the British Isles originated from one or more introductions of melanic gray squirrels from North America. We also conclude that variations in the MC1R are not associated with melanism in the fox and red squirrels.

Temperature adaptation of active sodium-potassium transport and of passive permeability in erythrocytes of ground squirrels.

NASA Technical Reports Server (NTRS)

Kimzey, S. L.; Willis, J. S.

1971-01-01

Unidirectional active and passive fluxes of K-42 and Na-24 were measured in red blood cells of ground squirrels (hibernators) and guinea pigs (nonhibernators). As the temperature was lowered, ?active' (ouabain-sensitive) K influx and Na efflux were more considerably diminished in guinea pig cells than in those of ground squirrels. The fraction of total K influx which is ouabain-sensitive in red blood cells of ground squirrels was virtually constant at all temperatures, whereas it decreased abruptly in guinea pig cells as temperature was lowered.

Basic math in monkeys and college students.

PubMed

Cantlon, Jessica F; Brannon, Elizabeth M

2007-12-01

Adult humans possess a sophisticated repertoire of mathematical faculties. Many of these capacities are rooted in symbolic language and are therefore unlikely to be shared with nonhuman animals. However, a subset of these skills is shared with other animals, and this set is considered a cognitive vestige of our common evolutionary history. Current evidence indicates that humans and nonhuman animals share a core set of abilities for representing and comparing approximate numerosities nonverbally; however, it remains unclear whether nonhuman animals can perform approximate mental arithmetic. Here we show that monkeys can mentally add the numerical values of two sets of objects and choose a visual array that roughly corresponds to the arithmetic sum of these two sets. Furthermore, monkeys' performance during these calculations adheres to the same pattern as humans tested on the same nonverbal addition task. Our data demonstrate that nonverbal arithmetic is not unique to humans but is instead part of an evolutionarily primitive system for mathematical thinking shared by monkeys.

Correlates of vulnerability in Chiricahua fox squirrels

Treesearch

Bret S. Pasch; John L. Koprowski

2005-01-01

Chiricahua fox squirrels (Sciurus nayaritensis chiricahuae) are endemic to the Chiricahua Mountains of southeastern Arizona. A paucity of natural history information and uncertain conservation status served as impetus for us to initiate a descriptive ecological study of the species. We examined reproductive and population ecology of Chiricahua fox...

Does repeated human intrusion alter use of wildland sites by red squirrels? Multiyear experimental evidence

Treesearch

Kevin J. Gutzwiller; Samuel K. Riffell

2008-01-01

Intrusion by humans into wildlife habitat during recreational activities has become a worldwide conservation concern. Low levels of intrusion, which occur frequently in many wildlands, could influence use of sites by red squirrels (Tamiasciurus hudsonicus) and have important ramifications for conservation. Red squirrels can influence forest...

Cluster of Sylvatic Epidemic Typhus Cases Associated with Flying Squirrels, 2004–2006

PubMed Central

Chapman, Alice S.; Swerdlow, David L.; Dato, Virginia M.; Anderson, Alicia D.; Moodie, Claire E.; Marriott, Chandra; Amman, Brian; Hennessey, Morgan; Fox, Perry; Green, Douglas B.; Pegg, Eric; Nicholson, William L.; Eremeeva, Marina E.

2009-01-01

In February 2006, a diagnosis of sylvatic epidemic typhus in a counselor at a wilderness camp in Pennsylvania prompted a retrospective investigation. From January 2004 through January 2006, 3 more cases were identified. All had been counselors at the camp and had experienced febrile illness with myalgia, chills, and sweats; 2 had been hospitalized. All patients had slept in the same cabin and reported having seen and heard flying squirrels inside the wall adjacent to their bed. Serum from each patient had evidence of infection with Rickettsia prowazekii. Analysis of blood and tissue from 14 southern flying squirrels trapped in the woodlands around the cabin indicated that 71% were infected with R. prowazekii. Education and control measures to exclude flying squirrels from housing are essential to reduce the likelihood of sylvatic epidemic typhus. PMID:19624912

Hypothalamic-pituitary-adrenal axis physiology and cognitive control of behavior in stress inoculated monkeys.

PubMed

Parker, Karen J; Buckmaster, Christine L; Lindley, Steven E; Schatzberg, Alan F; Lyons, David M

2012-01-01

Monkeys exposed to stress inoculation protocols early in life subsequently exhibit diminished neurobiological responses to moderate psychological stressors and enhanced cognitive control of behavior during juvenile development compared to non-inoculated monkeys. The present experiments extended these findings and revealed that stress inoculated monkeys: (a) mount neurobiological responses equivalent to non-inoculated monkeys when the stressor is of sufficient intensity, and (b) continue to exhibit enhanced cognitive control as young adults compared to non-inoculated monkeys. These results suggest that stress inoculation protocols alter the appraisal of and response to moderate stressors as less threatening and permanently enhance cognitive control, at least through early adulthood. These data therefore support the notion that the stress inoculation phenotype reflects stress resilience rather than stress pathology.

Laboratory evaluation of anticoagulant-treated baits for control of the northern palm squirrel, Funambulus pennanti Wroughton.

PubMed Central

Mathur, R. P.; Prakash, I.

1980-01-01

Individually caged northern palm squirrels, Funambulus pennanti, were fed with bait containing 0.025% warfarin or fumarin, 0.0075% chlorophacinone or 0.005% brodifacoum for a fixed number of days varying from 1 to 14. Brodifacoum (WBA 8119) was found most toxic since 66% and 70% of the animals died after one and two days' feeding respectively. Chlorophacinone killed 70% of the squirrels after three days' feeding. Squirrels were relatively tolerant to warfarin and fumarin since the mortality after a period of 14 days' feeding was only 58% and 75% respectively. PMID:7462592

Laboratory evaluation of anticoagulant-treated baits for control of the northern palm squirrel, Funambulus pennanti Wroughton.

PubMed

Mathur, R P; Prakash, I

1980-12-01

Individually caged northern palm squirrels, Funambulus pennanti, were fed with bait containing 0.025% warfarin or fumarin, 0.0075% chlorophacinone or 0.005% brodifacoum for a fixed number of days varying from 1 to 14. Brodifacoum (WBA 8119) was found most toxic since 66% and 70% of the animals died after one and two days' feeding respectively. Chlorophacinone killed 70% of the squirrels after three days' feeding. Squirrels were relatively tolerant to warfarin and fumarin since the mortality after a period of 14 days' feeding was only 58% and 75% respectively.

Endovascular ischemic stroke models of adult rhesus monkeys: a comparison of two endovascular methods.

PubMed

Wu, Di; Chen, Jian; Wang, Bincheng; Zhang, Mo; Shi, Jingfei; Ma, Yanhui; Zhu, Zixin; Yan, Feng; He, Xiaoduo; Li, Shengli; Dornbos Iii, David; Ding, Yuchuan; Ji, Xunming

2016-08-18

To further investigate and improve upon current stroke models in nonhuman primates, infarct size, neurologic function and survival were evaluated in two endovascular ischemic models in sixteen rhesus monkeys. The first method utilized a micro-catheter or an inflatable balloon to occlude the M1 segment in six monkeys. In the second model, an autologous clot was injected via a micro-catheter into the M1 segment in ten monkeys. MRI scanning was performed on all monkeys both at baseline and 3 hours after the onset of ischemia. Spetzler neurologic functions were assessed post-operatively, and selective perfusion deficits were confirmed by DSA and MRI in all monkeys. Animals undergoing micro-catheter or balloon occlusion demonstrated more profound hemiparesis, larger infarct sizes, lower Spetzler neurologic scores and increased mortality compared to the thrombus occlusion group. In animals injected with the clot, there was no evidence of dissolution, and the thrombus was either near the injection site (M1) or flushed into the superior division of the MCA (M2). All animals survived the M2 occlusion. M1 occlusion with thrombus generated 50% mortality. This study highlighted clinically important differences in these two models, providing a platform for further study of a translational thromboembolic model of acute ischemic stroke.

Subcortical afferent connections of the amygdala in the monkey

NASA Technical Reports Server (NTRS)

Mehler, W. R.

1980-01-01

The cells of origin of the afferent connections of the amygdala in the rhesus and squirrel monkeys are determined according to the retrograde axonal transport of the enzyme horseradish peroxidase injected into various quadrants of the amygdala. Analysis of the distribution of enzyme-labeled cells reveals afferent amygdalar connections with the ipsilateral halves of the midline nucleus paraventricularis thalami and both the parvo- and magnocellular parts of the nucleus subparafascicularis in the dorsal thalamus, all the subdivisions of the midline nucleus centralis complex, the nucleus reuniens ventralis and the nucleus interventralis. The largest populations of enzyme-labeled cells in the hypothalamus are found to lie in the middle and posterior parts of the ipsilateral, lateral hypothalamus and the ventromedial hypothalamic nucleus, with scattered cells in the supramammillary and dorsomedial nuclei and the posterior hypothalamic area, Tsai's ventral tegmental area, the rostral and caudal subdivisions of the nucleus linearis in the midbrain and the dorsal raphe nucleus. The most conspicuous subdiencephalic source of amygdalar afferent connections is observed to be the pars lateralis of the nucleus parabrachialis in the dorsolateral pontine tegmentum, with a few labeled cells differentiated from pigmented cells in the locus coeruleus.

Living on the edge: Space use of Eurasian red squirrels in marginal high-elevation habitat

NASA Astrophysics Data System (ADS)

Romeo, Claudia; Wauters, Lucas A.; Preatoni, Damiano; Tosi, Guido; Martinoli, Adriano

2010-11-01

In marginal habitats located at the edge of a species' range, environmental conditions are frequently extreme and individuals may be subject to different selective pressures compared to central populations. These so-called edge or marginal populations tend to have lower densities and reproductive rates than populations located in more suitable habitats, but little is known about local adaptations in spacing behavior. We studied space use and social organization in a population of Eurasian red squirrels ( Sciurus vulgaris) in a high-elevation marginal habitat of dwarf mountain pine ( Pinus mugo) and compared it with spacing patterns in high-quality Scots pine ( Pinus sylvestris) forest at lower-elevation. Home ranges and core areas were larger in the marginal habitat. In both habitats, males used larger home ranges than females, but sex differences in core area size were significant only in the edge population. Patterns of core area overlap were similar in both habitats with intra-sexual territoriality among adult females and higher degrees of inter-sexual overlap, typical for the species throughout its range. However, low densities in the edge population resulted in higher female by males overlap in spring-summer, suggesting males increased home ranges and core areas during mating season to augment access to estrus females. Thus, in the marginal habitat, with low food abundance and low population densities, linked with extreme winter conditions, squirrels, especially males, used large home ranges. Finally, squirrels responded more strongly to variation in food availability (inverse relation between home range size and seed abundance), and even to fluctuations in density (inverse relation between core area size and density of animals of the same sex), in the marginal than in the high-quality habitat, suggesting high behavioral plasticity to respond to the ecological constraints in marginal habitats.

Molecular Mechanism of Species-dependent Sweet Taste toward Artificial Sweeteners

PubMed Central

Liu, Bo; Ha, Matthew; Meng, Xuan-Yu; Kaur, Tanno; Khaleduzzaman, Mohammed; Zhang, Zhe; Jiang, Peihua; Li, Xia; Cui, Meng

2011-01-01

The heterodimer of Tas1R2 and Tas1R3 is a broadly acting sweet taste receptor, which mediates mammalian sweet taste toward natural and artificial sweeteners and sweet-tasting proteins. Perception of sweet taste is a species selective physiological process. For instance, artificial sweeteners aspartame and neotame taste sweet to humans, apes and Old World monkeys but not to New World monkeys and rodents. Although specific regions determining the activation of the receptors by these sweeteners have been identified, the molecular mechanism of species-dependent sweet taste remains elusive. Using human/squirrel monkey chimeras, mutagenesis and molecular modeling, we reveal that the different responses of mammalian species towards the artificial sweeteners aspartame and neotame are determined by the steric effect of a combination of a few residues in the ligand binding pocket. Residues S40 and D142 in the human Tas1R2, which correspond to residues T40 and E142 in the squirrel monkey Tas1R2, were found to be the critical residues for the species dependent difference in sweet taste. In addition, human Tas1R2 residue I67, which corresponds to S67 in squirrel monkey receptor, modulates the higher affinity of neotame than that of aspartame. Our studies not only shed light on the molecular mechanism of species dependent sweet taste toward artificial sweeteners, but also provide guidance for designing novel effective artificial sweet compounds. PMID:21795555

Molecular mechanism of species-dependent sweet taste toward artificial sweeteners.

PubMed

Liu, Bo; Ha, Matthew; Meng, Xuan-Yu; Kaur, Tanno; Khaleduzzaman, Mohammed; Zhang, Zhe; Jiang, Peihua; Li, Xia; Cui, Meng

2011-07-27

The heterodimer of Tas1R2 and Tas1R3 is a broadly acting sweet taste receptor, which mediates mammalian sweet taste toward natural and artificial sweeteners and sweet-tasting proteins. Perception of sweet taste is a species-selective physiological process. For instance, artificial sweeteners aspartame and neotame taste sweet to humans, apes, and Old World monkeys but not to New World monkeys and rodents. Although specific regions determining the activation of the receptors by these sweeteners have been identified, the molecular mechanism of species-dependent sweet taste remains elusive. Using human/squirrel monkey chimeras, mutagenesis, and molecular modeling, we reveal that the different responses of mammalian species toward the artificial sweeteners aspartame and neotame are determined by the steric effect of a combination of a few residues in the ligand binding pocket. Residues S40 and D142 in the human Tas1R2, which correspond to residues T40 and E142 in the squirrel monkey Tas1R2, were found to be the critical residues for the species-dependent difference in sweet taste. In addition, human Tas1R2 residue I67, which corresponds to S67 in squirrel monkey receptor, modulates the higher affinity of neotame than of aspartame. Our studies not only shed light on the molecular mechanism of species-dependent sweet taste toward artificial sweeteners, but also provide guidance for designing novel effective artificial sweet compounds.

Thinning of young Douglas-fir forests decreases density of northern flying squirrels in the Oregon Cascades

USGS Publications Warehouse

Manning, Tom; Hagar, Joan C.; McComb, Brenda C.

2012-01-01

Large-scale commercial thinning of young forests in the Pacific Northwest is currently promoted on public lands to accelerate the development of late-seral forest structure for the benefit of wildlife species such as northern spotted owls (Strix occidentalis caurina) and their prey, including the northern flying squirrel (Glaucomys sabrinus). Attempts to measure the impact of commercial thinning on northern flying squirrels have mostly addressed short-term effects (2–5 years post-thinning) and the few published studies of longer-term results have been contradictory. We measured densities of northern flying squirrels 11–13 years after thinning of young (55–65 years) Douglas-fir forest stands in the Cascade Range of Oregon, as part of the Young Stand Thinning & Diversity Study. The study includes four replicate blocks, each consisting of an unthinned control stand and one stand each of the following thinning treatments: Heavy Thin; Light Thin; and Light Thin with Gaps. Thinning decreased density of northern flying squirrels, and squirrel densities were significantly lower in heavily thinned stands than in more lightly thinned stands. Regression analysis revealed a strong positive relationship of flying squirrel density with density of large (>30 cm diameter) standing dead trees and a negative relationship with percent cover of low understory shrubs. Maintaining sufficient area and connectivity of dense, closed canopy forest is recommended as a strategy to assure that long-term goals of promoting late-seral structure do not conflict with short-term habitat requirements of this important species.

Do you see what I see? A comparative investigation of the Delboeuf illusion in humans (Homo sapiens), rhesus monkeys (Macaca mulatta), and capuchin monkeys (Cebus apella).

PubMed

Parrish, Audrey E; Brosnan, Sarah F; Beran, Michael J

2015-10-01

Studying visual illusions is critical to understanding typical visual perception. We investigated whether rhesus monkeys (Macaca mulatta) and capuchin monkeys (Cebus apella) perceived the Delboeuf illusion in a similar manner as human adults (Homo sapiens). To test this, in Experiment 1, we presented monkeys and humans with a relative discrimination task that required subjects to choose the larger of 2 central dots that were sometimes encircled by concentric rings. As predicted, humans demonstrated evidence of the Delboeuf illusion, overestimating central dots when small rings surrounded them and underestimating the size of central dots when large rings surrounded them. However, monkeys did not show evidence of the illusion. To rule out an alternate explanation, in Experiment 2, we presented all species with an absolute classification task that required them to classify a central dot as "small" or "large." We presented a range of ring sizes to determine whether the Delboeuf illusion would occur for any dot-to-ring ratios. Here, we found evidence of the Delboeuf illusion in all 3 species. Humans and monkeys underestimated central dot size to a progressively greater degree with progressively larger rings. The Delboeuf illusion now has been extended to include capuchin monkeys and rhesus monkeys, and through such comparative investigations we can better evaluate hypotheses regarding illusion perception among nonhuman animals. (c) 2015 APA, all rights reserved).

Nest tree use by the endangered Virginia northern flying squirrel in the central Appalachian Mountains

Treesearch

Jennifer M. Menzel; W. Mark Ford; John W. Edwards; Michael A. Menzel

2004-01-01

Little is known about nest tree use of the endangered Virginia northern flying squirrel (Glaucomys sabrinus fuscus). Because nesting sites could be a limiting factor, it is important to understand the denning ecology to further manage and protect this subspecies. We compared characteristics of nest trees used by Virginia northern flying squirrels...

Functional organization of the medial temporal lobe memory system following neonatal hippocampal lesion in rhesus monkeys.

PubMed

Chareyron, Loïc J; Banta Lavenex, Pamela; Amaral, David G; Lavenex, Pierre

2017-12-01

Hippocampal damage in adult humans impairs episodic and semantic memory, whereas hippocampal damage early in life impairs episodic memory but leaves semantic learning relatively preserved. We have previously shown a similar behavioral dissociation in nonhuman primates. Hippocampal lesion in adult monkeys prevents allocentric spatial relational learning, whereas spatial learning persists following neonatal lesion. Here, we quantified the number of cells expressing the immediate-early gene c-fos, a marker of neuronal activity, to characterize the functional organization of the medial temporal lobe memory system following neonatal hippocampal lesion. Ninety minutes before brain collection, three control and four adult monkeys with bilateral neonatal hippocampal lesions explored a novel environment to activate brain structures involved in spatial learning. Three other adult monkeys with neonatal hippocampal lesions remained in their housing quarters. In unlesioned monkeys, we found high levels of c-fos expression in the intermediate and caudal regions of the entorhinal cortex, and in the perirhinal, parahippocampal, and retrosplenial cortices. In lesioned monkeys, spatial exploration induced an increase in c-fos expression in the intermediate field of the entorhinal cortex, the perirhinal, parahippocampal, and retrosplenial cortices, but not in the caudal entorhinal cortex. These findings suggest that different regions of the medial temporal lobe memory system may require different types of interaction with the hippocampus in support of memory. The caudal perirhinal cortex, the parahippocampal cortex, and the retrosplenial cortex may contribute to spatial learning in the absence of functional hippocampal circuits, whereas the caudal entorhinal cortex may require hippocampal output to support spatial learning.

Ames Research Center Life Sciences Payload Project for Spacelab Mission 3

NASA Technical Reports Server (NTRS)

Callahan, P. X.; Tremor, J.; Lund, G.; Wagner, W. L.

1983-01-01

The Research Animal Holding Facility, developed to support rodent and squirrel monkey animal husbandry in the Spacelab environment, is to be tested during the Spacelab Mission 3 flight. The configuration and function of the payload hardware elements, the assembly and test program, the operational rationale, and the scientific approach of this mission are examined. Topics covered include animal life support systems, the squirrel monkey restraint, the camera-mirror system, the dynamic environment measurement system, the biotelemetry system, and the ground support equipment. Consideration is also given to animal pretests, loading the animals during their 12 hour light cycle, and animal early recovery after landing. This mission will be the first time that relatively large samples of monkeys and rats will be flown in space and also cared for and observed by man.

Acute fatal toxoplasmosis in squirrels (Sciurus carolensis) with bradyzoites in visceral tissues.

PubMed

Dubey, J P; Hodgin, E C; Hamir, A N

2006-06-01

Acute toxoplasmosis was diagnosed in 3 gray squirrels (Sciurus carolensis) from Louisiana and Pennsylvania. The predominant lesion was multifocal necrosis in several organs, especially of the lymph nodes. Numerous Toxoplasma gondii tachyzoites were seen in lesions, and the diagnosis was confirmed immunohistochemically by reaction with polyclonal T. gondii-specific antibodies. Tissue cysts were seen in several organs, including lung alveoli. The presence of tissue cysts in alveoli of pet squirrels maybe of public health concern if tissue cysts excreted in nasal secretions are swallowed by children.

Seasonal Patterns of Body Temperature Daily Rhythms in Group-Living Cape Ground Squirrels Xerus inauris

PubMed Central

Scantlebury, Michael; Danek-Gontard, Marine; Bateman, Philip W.; Bennett, Nigel C.; Manjerovic, Mary-Beth; Joubert, Kenneth E.; Waterman, Jane M.

2012-01-01

Organisms respond to cyclical environmental conditions by entraining their endogenous biological rhythms. Such physiological responses are expected to be substantial for species inhabiting arid environments which incur large variations in daily and seasonal ambient temperature (Ta). We measured core body temperature (Tb) daily rhythms of Cape ground squirrels Xerus inauris inhabiting an area of Kalahari grassland for six months from the Austral winter through to the summer. Squirrels inhabited two different areas: an exposed flood plain and a nearby wooded, shady area, and occurred in different social group sizes, defined by the number of individuals that shared a sleeping burrow. Of a suite of environmental variables measured, maximal daily Ta provided the greatest explanatory power for mean Tb whereas sunrise had greatest power for Tb acrophase. There were significant changes in mean Tb and Tb acrophase over time with mean Tb increasing and Tb acrophase becoming earlier as the season progressed. Squirrels also emerged from their burrows earlier and returned to them later over the measurement period. Greater increases in Tb, sometimes in excess of 5°C, were noted during the first hour post emergence, after which Tb remained relatively constant. This is consistent with observations that squirrels entered their burrows during the day to ‘offload’ heat. In addition, greater Tb amplitude values were noted in individuals inhabiting the flood plain compared with the woodland suggesting that squirrels dealt with increased environmental variability by attempting to reduce their Ta-Tb gradient. Finally, there were significant effects of age and group size on Tb with a lower and less variable Tb in younger individuals and those from larger group sizes. These data indicate that Cape ground squirrels have a labile Tb which is sensitive to a number of abiotic and biotic factors and which enables them to be active in a harsh and variable environment. PMID:22558324

Comparison of functional recovery of manual dexterity after unilateral spinal cord lesion or motor cortex lesion in adult macaque monkeys.

PubMed

Hoogewoud, Florence; Hamadjida, Adjia; Wyss, Alexander F; Mir, Anis; Schwab, Martin E; Belhaj-Saif, Abderraouf; Rouiller, Eric M

2013-01-01

In relation to mechanisms involved in functional recovery of manual dexterity from cervical cord injury or from motor cortical injury, our goal was to determine whether the movements that characterize post-lesion functional recovery are comparable to original movement patterns or do monkeys adopt distinct strategies to compensate the deficits depending on the type of lesion? To this aim, data derived from earlier studies, using a skilled finger task (the modified Brinkman board from which pellets are retrieved from vertical or horizontal slots), in spinal cord and motor cortex injured monkeys were analyzed and compared. Twelve adult macaque monkeys were subjected to a hemi-section of the cervical cord (n = 6) or to a unilateral excitotoxic lesion of the hand representation in the primary motor cortex (n = 6). In addition, in each subgroup, one half of monkeys (n = 3) were treated for 30 days with a function blocking antibody against the neurite growth inhibitory protein Nogo-A, while the other half (n = 3) represented control animals. The motor deficits, and the extent and time course of functional recovery were assessed. For some of the parameters investigated (wrist angle for horizontal slots and movement types distribution for vertical slots after cervical injury; movement types distribution for horizontal slots after motor cortex lesion), post-lesion restoration of the original movement patterns ("true" recovery) led to a quantitatively better functional recovery. In the motor cortex lesion groups, pharmacological reversible inactivation experiments showed that the peri-lesion territory of the primary motor cortex or re-arranged, spared domain of the lesion zone, played a major role in the functional recovery, together with the ipsilesional intact premotor cortex.

Seasonal, spatial, and maternal effects on gut microbiome in wild red squirrels.

PubMed

Ren, Tiantian; Boutin, Stan; Humphries, Murray M; Dantzer, Ben; Gorrell, Jamieson C; Coltman, David W; McAdam, Andrew G; Wu, Martin

2017-12-21

Our understanding of gut microbiota has been limited primarily to findings from human and laboratory animals, but what shapes the gut microbiota in nature remains largely unknown. To fill this gap, we conducted a comprehensive study of gut microbiota of a well-studied North American red squirrel (Tamiasciurus hudsonicus) population. Red squirrels are territorial, solitary, and live in a highly seasonal environment and therefore represent a very attractive system to study factors that drive the temporal and spatial dynamics of gut microbiota. For the first time, this study revealed significant spatial patterns of gut microbiota within a host population, suggesting limited dispersal could play a role in shaping and maintaining the structure of gut microbial communities. We also found a remarkable seasonal rhythm in red squirrel's gut microbial composition manifested by a tradeoff between relative abundance of two genera Oscillospira and Corpococcus and clearly associated with seasonal variation in diet availability. Our results show that in nature, environmental factors exert a much stronger influence on gut microbiota than host-associated factors including age and sex. Despite strong environmental effects, we found clear evidence of individuality and maternal effects, but host genetics did not seem to be a significant driver of the gut microbial communities in red squirrels. Taken together, the results of this study emphasize the importance of external ecological factors rather than host attributes in driving temporal and spatial patterns of gut microbiota in natural environment.

Gastrointestinal parasites of the colobus monkeys of Uganda.

PubMed

Gillespie, Thomas R; Greiner, Ellis C; Chapman, Colin A

2005-06-01

From August 1997 to July 2003, we collected 2,103 fecal samples from free-ranging individuals of the 3 colobus monkey species of Uganda-the endangered red colobus (Piliocolobus tephrosceles), the eastern black-and-white colobus (Colobus guereza), and the Angolan black-and-white colobus (C. angolensis)--to identify and determine the prevalence of gastrointestinal parasites. Helminth eggs, larvae, and protozoan cysts were isolated by sodium nitrate flotation and fecal sedimentation. Coprocultures facilitated identification of helminths. Seven nematodes (Strongyloides fulleborni, S. stercoralis, Oesophagostomum sp., an unidentified strongyle, Trichuris sp., Ascaris sp., and Colobenterobius sp.), 1 cestode (Bertiella sp.), 1 trematode (Dicrocoeliidae), and 3 protozoans (Entamoeba coli, E. histolytica, and Giardia lamblia) were detected. Seasonal patterns of infection were not apparent for any parasite species infecting colobus monkeys. Prevalence of S. fulleborni was higher in adult male compared to adult female red colobus, but prevalence did not differ for any other shared parasite species between age and sex classes.

Peripheral refraction in normal infant rhesus monkeys

PubMed Central

Hung, Li-Fang; Ramamirtham, Ramkumar; Huang, Juan; Qiao-Grider, Ying; Smith, Earl L.

2008-01-01

Purpose To characterize peripheral refractions in infant monkeys. Methods Cross-sectional data for horizontal refractions were obtained from 58 normal rhesus monkeys at 3 weeks of age. Longitudinal data were obtained for both the vertical and horizontal meridians from 17 monkeys. Refractive errors were measured by retinoscopy along the pupillary axis and at eccentricities of 15, 30, and 45 degrees. Axial dimensions and corneal power were measured by ultrasonography and keratometry, respectively. Results In infant monkeys, the degree of radial astigmatism increased symmetrically with eccentricity in all meridians. There were, however, initial nasal-temporal and superior-inferior asymmetries in the spherical-equivalent refractive errors. Specifically, the refractions in the temporal and superior fields were similar to the central ametropia, but the refractions in the nasal and inferior fields were more myopic than the central ametropia and the relative nasal field myopia increased with the degree of central hyperopia. With age, the degree of radial astigmatism decreased in all meridians and the refractions became more symmetrical along both the horizontal and vertical meridians; small degrees of relative myopia were evident in all fields. Conclusions As in adult humans, refractive error varied as a function of eccentricity in infant monkeys and the pattern of peripheral refraction varied with the central refractive error. With age, emmetropization occurred for both central and peripheral refractive errors resulting in similar refractions across the central 45 degrees of the visual field, which may reflect the actions of vision-dependent, growth-control mechanisms operating over a wide area of the posterior globe. PMID:18487366

Smoked aluminum track stations record flying squirrel occurrence

Treesearch

Martin G. Raphael; Cathy A. Taylor; Reginald H. Barrett

1986-01-01

Smoked aluminum track stations are a useful technique for studying patterns of abundance and distribution of northern flying squirrel (Glaucomys sabrinus). They are easily transported to remote field sites, allow permanent preservation of tracks, and yield frequency-of-occurrence information. A study in Douglas-fir (Pseseudotsuga menziesii...

The adaptive function of masturbation in a promiscuous African ground squirrel.

PubMed

Waterman, Jane M

2010-09-28

Studies of animal mating systems increasingly emphasize female multiple mating and cryptic sexual selection, particularly sperm competition. Males under intense sperm competition may manipulate sperm quantity and quality through masturbation, which could waste sperm and decrease fertility. I examined the factors influencing masturbation by male Cape ground squirrels (Xerus inauris) in light of a number of functional hypotheses. Observational data on a marked population of squirrels were collected in east-central Namibia using scan and all-occurrences sampling. Masturbation was far more frequent on days of female oestrus and mostly occurred after copulation. Masturbation rates were higher in dominant males, which copulate more, than in subordinates and increased with number of mates a female accepts. These results suggest that masturbation in this species was not a response to sperm competition nor a sexual outlet by subordinates that did not copulate. Instead masturbation could function as a form of genital grooming. Female Cape ground squirrels mate with up to 10 males in a 3-hr oestrus, and by masturbating after copulation males could reduce the chance of infection. Sexually transmitted infections (STIs) can profoundly affect fertility, and their consequences for mating strategies need to be examined more fully.

Ecological scale and forest development: squirrels, dietary fungi, and vascular plants in managed and unmanaged forests.

Treesearch

A.B. Carey; J. Kershner; B. Biswell; L.S. Dominguez de Toledo

1999-01-01

Understanding ecological processes and their spatial scales is key to managing ecosystems for biodiversity, especially for species associated with late-seral forest. We focused on 2 species of squirrel (Sciuridae: northern flying squirrel, Glaucomys sabrinus, and Townsend's chipmunk, Tamias townsendii) in a crosssectional survey of managed and natural stands in...

Home Range, Habitat Selection, and Population Dynamics of Southern Flying Squirrels in Managed Forests in Arkansas

Treesearch

James F. Taulman; Kimberly G. Smith

2004-01-01

Abstract After experimental harvests on 18 mature pine-hardwood stands in 6 replicated groups, flying squirrels changed from uniform pre-harvest patterns of nest box use to concentrating on protected greenbelt (GB) areas on harvested stands. Squirrel densities declined on all harvested stands as densities increased on three control stands. Fifty...

Spatial organization of northern flying squirrels, Glaucomys sabrinus: Territoriality in females?

USGS Publications Warehouse

Smith, J.R.; Vuren, D.H.V.; Kelt, D.A.; Johnson, M.L.

2011-01-01

We determined home-range overlap among northern flying squirrels (Glaucomys sabrinus) to assess their spatial organization. We found extensive home-range overlap among females, and though this overlap could reflect social behavior, we found no evidence of attraction among females, with only one instance of den sharing. Instead, our results suggest that females share foraging areas but may be territorial in portions of the home range, especially around den trees and during young-rearing. Home-range overlap could also result from, the extrinsic effect of forest fragmentation due to timber harvest, which might impede dispersal and force squirrels to cluster on remaining fragments of suitable habitat.

Implications of Hybridization, NUMTs, and Overlooked Diversity for DNA Barcoding of Eurasian Ground Squirrels

PubMed Central

Ermakov, Oleg A.; Simonov, Evgeniy; Surin, Vadim L.; Titov, Sergey V.; Brandler, Oleg V.; Ivanova, Natalia V.; Borisenko, Alex V.

2015-01-01

The utility of DNA Barcoding for species identification and discovery has catalyzed a concerted effort to build the global reference library; however, many animal groups of economical or conservational importance remain poorly represented. This study aims to contribute DNA barcode records for all ground squirrel species (Xerinae, Sciuridae, Rodentia) inhabiting Eurasia and to test efficiency of this approach for species discrimination. Cytochrome c oxidase subunit 1 (COI) gene sequences were obtained for 97 individuals representing 16 ground squirrel species of which 12 were correctly identified. Taxonomic allocation of some specimens within four species was complicated by geographically restricted mtDNA introgression. Exclusion of individuals with introgressed mtDNA allowed reaching a 91.6% identification success rate. Significant COI divergence (3.5–4.4%) was observed within the most widespread ground squirrel species (Spermophilus erythrogenys, S. pygmaeus, S. suslicus, Urocitellus undulatus), suggesting the presence of cryptic species. A single putative NUMT (nuclear mitochondrial pseudogene) sequence was recovered during molecular analysis; mitochondrial COI from this sample was amplified following re-extraction of DNA. Our data show high discrimination ability of 100 bp COI fragments for Eurasian ground squirrels (84.3%) with no incorrect assessments, underscoring the potential utility of the existing reference librariy for the development of diagnostic ‘mini-barcodes’. PMID:25617768

Comparison of Functional Recovery of Manual Dexterity after Unilateral Spinal Cord Lesion or Motor Cortex Lesion in Adult Macaque Monkeys

PubMed Central

Hoogewoud, Florence; Hamadjida, Adjia; Wyss, Alexander F.; Mir, Anis; Schwab, Martin E.; Belhaj-Saif, Abderraouf; Rouiller, Eric M.

2013-01-01

In relation to mechanisms involved in functional recovery of manual dexterity from cervical cord injury or from motor cortical injury, our goal was to determine whether the movements that characterize post-lesion functional recovery are comparable to original movement patterns or do monkeys adopt distinct strategies to compensate the deficits depending on the type of lesion? To this aim, data derived from earlier studies, using a skilled finger task (the modified Brinkman board from which pellets are retrieved from vertical or horizontal slots), in spinal cord and motor cortex injured monkeys were analyzed and compared. Twelve adult macaque monkeys were subjected to a hemi-section of the cervical cord (n = 6) or to a unilateral excitotoxic lesion of the hand representation in the primary motor cortex (n = 6). In addition, in each subgroup, one half of monkeys (n = 3) were treated for 30 days with a function blocking antibody against the neurite growth inhibitory protein Nogo-A, while the other half (n = 3) represented control animals. The motor deficits, and the extent and time course of functional recovery were assessed. For some of the parameters investigated (wrist angle for horizontal slots and movement types distribution for vertical slots after cervical injury; movement types distribution for horizontal slots after motor cortex lesion), post-lesion restoration of the original movement patterns (“true” recovery) led to a quantitatively better functional recovery. In the motor cortex lesion groups, pharmacological reversible inactivation experiments showed that the peri-lesion territory of the primary motor cortex or re-arranged, spared domain of the lesion zone, played a major role in the functional recovery, together with the ipsilesional intact premotor cortex. PMID:23885254

A comparison of habitat use and demography of red squirrels at the southern edge of their range

Treesearch

Katherine M. Leonard; John L. Koprowski

2009-01-01

Populations at the edge of their geographic range may demonstrate different population dynamics from central populations. Endangered Mt. Graham red squirrels (Tamiasciurus hudsonicus grahamensis), endemic to southeastern Arizona, represent the southernmost red squirrel population and are found at lower densities than conspecifics in the center of the...

Circadian rhythms of body temperature and locomotor activity in the antelope ground squirrel, Ammospermophilus leucurus.

PubMed

Refinetti, Roberto; Kenagy, G J

2018-02-01

We studied circadian rhythms of body temperature and locomotor activity in antelope ground squirrels (Ammospermophilus leucurus) under laboratory conditions of a 12L:12D light-dark cycle and in constant darkness. Antelope ground squirrels are diurnally active and, exceptionally among ground squirrels and other closely related members of the squirrel family in general, they do not hibernate. Daily oscillations in body temperature consisted of a rise in temperature during the daytime activity phase of the circadian cycle and a decrease in temperature during the nighttime rest phase. The body temperature rhythms were robust (71% of maximal strength) with a daily range of oscillation of 4.6°C, a daytime mean of 38.7°C, and a nighttime mean of 34.1°C (24-h overall mean 36.4°C). The body temperature rhythm persisted in continuous darkness with a free-running period of 24.2h. This pattern is similar to that of hibernating species of ground squirrels but with a wave form more similar to that of non-hibernating rodents. Daily oscillations in body temperature were correlated with individual bouts of activity, but daytime temperatures were higher than nighttime temperatures even when comparing short episodes of nocturnal activity that were as intense as diurnal activity. This suggests that although muscular thermogenesis associated with locomotor activity can modify the level of body temperature, the circadian rhythm of body temperature is not simply a consequence of the circadian rhythm of activity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Atypical den use of Carolina Northern Flying Squirrels (Glaucomys sabrinus coloratus) in the southern Appalachian Mountains

USGS Publications Warehouse

Diggins, Corinne A.; Kelly, Christine A.; Ford, W. Mark

2015-01-01

Glaucomys sabrinus coloratus (Carolina Northern Flying Squirrel) is a federally endangered subspecies that occurs in high elevation forests of the southern Appalachian Mountains. Denning sites may be a limiting factor for this subspecies in areas where cavity trees are not abundant or where interspecific competition from other tree squirrels occurs. This shortage can result in use of unusual denning sites, such as subterranean dens. Herein, we report atypical denning habits of radio-collared Carolina Northern Flying Squirrels in southwestern Virginia and western North Carolina from 2008 to 2011 and 2014. Increased knowledge of denning habitats may be beneficial for conservation and habitat management of this subspecies, particularly in sub-optimal or degraded habitats.

Seasonal patterns of body temperature daily rhythms in group-living Cape ground squirrels Xerus inauris.

PubMed

Scantlebury, Michael; Danek-Gontard, Marine; Bateman, Philip W; Bennett, Nigel C; Manjerovic, Mary Beth; Manjerovic, Mary-Beth; Joubert, Kenneth E; Waterman, Jane M

2012-01-01

Organisms respond to cyclical environmental conditions by entraining their endogenous biological rhythms. Such physiological responses are expected to be substantial for species inhabiting arid environments which incur large variations in daily and seasonal ambient temperature (T(a)). We measured core body temperature (T(b)) daily rhythms of Cape ground squirrels Xerus inauris inhabiting an area of Kalahari grassland for six months from the Austral winter through to the summer. Squirrels inhabited two different areas: an exposed flood plain and a nearby wooded, shady area, and occurred in different social group sizes, defined by the number of individuals that shared a sleeping burrow. Of a suite of environmental variables measured, maximal daily T(a) provided the greatest explanatory power for mean T(b) whereas sunrise had greatest power for T(b) acrophase. There were significant changes in mean T(b) and T(b) acrophase over time with mean T(b) increasing and T(b) acrophase becoming earlier as the season progressed. Squirrels also emerged from their burrows earlier and returned to them later over the measurement period. Greater increases in T(b), sometimes in excess of 5°C, were noted during the first hour post emergence, after which T(b) remained relatively constant. This is consistent with observations that squirrels entered their burrows during the day to 'offload' heat. In addition, greater T(b) amplitude values were noted in individuals inhabiting the flood plain compared with the woodland suggesting that squirrels dealt with increased environmental variability by attempting to reduce their T(a)-T(b) gradient. Finally, there were significant effects of age and group size on T(b) with a lower and less variable T(b) in younger individuals and those from larger group sizes. These data indicate that Cape ground squirrels have a labile T(b) which is sensitive to a number of abiotic and biotic factors and which enables them to be active in a harsh and variable

Social stimuli enhance phencyclidine (PCP) self-administration in rhesus monkeys

PubMed Central

Newman, Jennifer L.; Perry, Jennifer L.; Carroll, Marilyn E.

2007-01-01

Environmental factors, including social interaction, can alter the effects of drugs of abuse on behavior. The present study was conducted to examine the effects of social stimuli on oral phencyclidine (PCP) self-administration by rhesus monkeys. Ten adult rhesus monkeys (M. mulatta) were housed side by side in modular cages that could be configured to provide visual, auditory, and olfactory stimuli provided by another monkey located in the other side of the paired unit. During the first experiment, monkeys self-administered PCP (0.25 mg/ml) and water under concurrent fixed ratio (FR) 16 schedules of reinforcement with either a solid or a grid (social) partition separating each pair of monkeys. In the second experiment, a PCP concentration-response relationship was determined under concurrent progressive ratio (PR) schedules of reinforcement under the solid and grid partition conditions. Under the concurrent FR 16 schedules, PCP and water self-administration was significantly higher during exposure to a cage mate through a grid partition than when a solid partition separated the monkeys. The relative reinforcing strength of PCP, as measured by PR break points, was greater during the grid partition condition compared to the solid partition condition indicated by an upward shift in the concentration-response curve. To determine whether the social stimuli provided by another monkey led to activation of the hypothalamic-pituitary-adrenal (HPA) axis, which may have evoked the increase of PCP self-administration during the grid partition condition, a third experiment was conducted to examine cortisol levels under the two housing conditions. A modest, but nonsignificant increase in cortisol levels was found upon switching from the solid to the grid partition condition. The results suggest that social stimulation among monkeys in adjoining cages leads to enhanced reinforcing strength of PCP. PMID:17560636

Administration of high doses of copper to capuchin monkeys does not cause liver damage but induces transcriptional activation of hepatic proliferative responses.

PubMed

Araya, Magdalena; Núñez, Héctor; Pavez, Leonardo; Arredondo, Miguel; Méndez, Marco; Cisternas, Felipe; Pizarro, Fernando; Sierralta, Walter; Uauy, Ricardo; González, Mauricio

2012-02-01

Liver cells respond to copper loading upregulating protective mechanisms. However, to date, except for liver content, there are no good indicators that identify individuals with excess liver copper. We hypothesized that administering high doses of copper to young (5.5 mg Cu · kg⁻¹ . d⁻¹) and adult (7.5 mg Cu · kg⁻¹ . d⁻¹) capuchin monkeys would induce detectable liver damage. Study groups included adult monkeys (2 females, 2 males) 3-3.5 y old at enrollment treated with copper for 36 mo (ACu); age-matched controls (1 female, 3 males) that did not receive additional copper (AC); young monkeys (2 female, 2 males) treated from birth with copper for 36 mo (YCu); and young age-matched controls (2 female, 2 males) that did not receive additional copper (YC). We periodically assessed clinical, blood biochemical, and liver histological indicators and at 36 mo the hepatic mRNA abundance of MT2a, APP, DMT1, CTR1, HGF, TGFβ, and NFκΒ only in adult monkeys. After 36 mo, the liver copper concentration was 4-5 times greater in treated monkeys relative to controls. All monkeys remained healthy with normal routine serum biochemical indices and there was no evidence of liver tissue damage. Relative mRNA abundance of HGF, TGFβ and NFκB was significantly greater in ACu than in AC monkeys. In conclusion, capuchin monkeys exposed to copper at doses up to 50 times the current upper level enhanced expression of genes related to inflammation and injury without clinical, blood biochemical, or histological evidence of liver damage.

The Functional Organization and Cortical Connections of Motor Cortex in Squirrels

PubMed Central

Cooke, Dylan F.; Padberg, Jeffrey; Zahner, Tony

2012-01-01

Despite extraordinary diversity in the rodent order, studies of motor cortex have been limited to only 2 species, rats and mice. Here, we examine the topographic organization of motor cortex in the Eastern gray squirrel (Sciurus carolinensis) and cortical connections of motor cortex in the California ground squirrel (Spermophilus beecheyi). We distinguish a primary motor area, M1, based on intracortical microstimulation (ICMS), myeloarchitecture, and patterns of connectivity. A sensorimotor area between M1 and the primary somatosensory area, S1, was also distinguished based on connections, functional organization, and myeloarchitecture. We term this field 3a based on similarities with area 3a in nonrodent mammals. Movements are evoked with ICMS in both M1 and 3a in a roughly somatotopic pattern. Connections of 3a and M1 are distinct and suggest the presence of a third far rostral field, termed “F,” possibly involved in motor processing based on its connections. We hypothesize that 3a is homologous to the dysgranular zone (DZ) in S1 of rats and mice. Our results demonstrate that squirrels have both similar and unique features of M1 organization compared with those described in rats and mice, and that changes in 3a/DZ borders appear to have occurred in both lineages. PMID:22021916

The Adaptive Function of Masturbation in a Promiscuous African Ground Squirrel

PubMed Central

Waterman, Jane M.

2010-01-01

Background Studies of animal mating systems increasingly emphasize female multiple mating and cryptic sexual selection, particularly sperm competition. Males under intense sperm competition may manipulate sperm quantity and quality through masturbation, which could waste sperm and decrease fertility. I examined the factors influencing masturbation by male Cape ground squirrels (Xerus inauris) in light of a number of functional hypotheses. Methodology Observational data on a marked population of squirrels were collected in east-central Namibia using scan and all-occurrences sampling. Findings Masturbation was far more frequent on days of female oestrus and mostly occurred after copulation. Masturbation rates were higher in dominant males, which copulate more, than in subordinates and increased with number of mates a female accepts. Conclusions These results suggest that masturbation in this species was not a response to sperm competition nor a sexual outlet by subordinates that did not copulate. Instead masturbation could function as a form of genital grooming. Female Cape ground squirrels mate with up to 10 males in a 3-hr oestrus, and by masturbating after copulation males could reduce the chance of infection. Sexually transmitted infections (STIs) can profoundly affect fertility, and their consequences for mating strategies need to be examined more fully. PMID:20927404

Inputs from regularly and irregularly discharging vestibular nerve afferents to secondary neurons in squirrel monkey vestibular nuclei. III. Correlation with vestibulospinal and vestibuloocular output pathways

NASA Technical Reports Server (NTRS)

Boyle, R.; Goldberg, J. M.; Highstein, S. M.

1992-01-01

1. A previous study measured the relative contributions made by regularly and irregularly discharging afferents to the monosynaptic vestibular nerve (Vi) input of individual secondary neurons located in and around the superior vestibular nucleus of barbiturate-anesthetized squirrel monkeys. Here, the analysis is extended to more caudal regions of the vestibular nuclei, which are a major source of both vestibuloocular and vestibulospinal pathways. As in the previous study, antidromic stimulation techniques are used to classify secondary neurons as oculomotor or spinal projecting. In addition, spinal-projecting neurons are distinguished by their descending pathways, their termination levels in the spinal cord, and their collateral projections to the IIIrd nucleus. 2. Monosynaptic excitatory postsynaptic potentials (EPSPs) were recorded intracellularly from secondary neurons as shocks of increasing strength were applied to Vi. Shocks were normalized in terms of the threshold (T) required to evoke field potentials in the vestibular nuclei. As shown previously, the relative contribution of irregular afferents to the total monosynaptic Vi input of each secondary neuron can be expressed as a %I index, the ratio (x100) of the relative sizes of the EPSPs evoked by shocks of 4 x T and 16 x T. 3. Antidromic stimulation was used to type secondary neurons as 1) medial vestibulospinal tract (MVST) cells projecting to spinal segments C1 or C6; 2) lateral vestibulospinal tract (LVST) cells projecting to C1, C6; or L1; 3) vestibulooculo-collic (VOC) cells projecting both to the IIIrd nucleus and by way of the MVST to C1 or C6; and 4) vestibuloocular (VOR) neurons projecting to the IIIrd nucleus but not to the spinal cord. Most of the neurons were located in the lateral vestibular nucleus (LV), including its dorsal (dLV) and ventral (vLV) divisions, and adjacent parts of the medial (MV) and descending nuclei (DV). Cells receiving quite different proportions of their direct inputs

Epigenetic mechanism underlying the development of polycystic ovary syndrome (PCOS)-like phenotypes in prenatally androgenized rhesus monkeys.

PubMed

Xu, Ning; Kwon, Soonil; Abbott, David H; Geller, David H; Dumesic, Daniel A; Azziz, Ricardo; Guo, Xiuqing; Goodarzi, Mark O

2011-01-01

The pathogenesis of polycystic ovary syndrome (PCOS) is poorly understood. PCOS-like phenotypes are produced by prenatal androgenization (PA) of female rhesus monkeys. We hypothesize that perturbation of the epigenome, through altered DNA methylation, is one of the mechanisms whereby PA reprograms monkeys to develop PCOS. Infant and adult visceral adipose tissues (VAT) harvested from 15 PA and 10 control monkeys were studied. Bisulfite treated samples were subjected to genome-wide CpG methylation analysis, designed to simultaneously measure methylation levels at 27,578 CpG sites. Analysis was carried out using Bayesian Classification with Singular Value Decomposition (BCSVD), testing all probes simultaneously in a single test. Stringent criteria were then applied to filter out invalid probes due to sequence dissimilarities between human probes and monkey DNA, and then mapped to the rhesus genome. This yielded differentially methylated loci between PA and control monkeys, 163 in infant VAT, and 325 in adult VAT (BCSVD P<0.05). Among these two sets of genes, we identified several significant pathways, including the antiproliferative role of TOB in T cell signaling and transforming growth factor-β (TGF-β) signaling. Our results suggest PA may modify DNA methylation patterns in both infant and adult VAT. This pilot study suggests that excess fetal androgen exposure in female nonhuman primates may predispose to PCOS via alteration of the epigenome, providing a novel avenue to understand PCOS in humans.

Nutritional benefits of Crematogaster mimosae ants and Acacia drepanolobium gum for patas monkeys and vervets in Laikipia, Kenya.

PubMed

Isbell, Lynne A; Rothman, Jessica M; Young, Peter J; Rudolph, Kathleen

2013-02-01

Patas monkeys (Erythrocebus patas) are midsized primates that feed extensively on the gum of Acacia drepanolobium and the ants are housed in swollen thorns of this Acacia. Their diet resembles that expected more of smaller bodied primates. Patas monkeys are also more like smaller bodied primates in reproducing at high rates. We sought to better understand the convergence of patas monkeys with smaller bodied primates by comparing their feeding behavior on ants and gum with that of closely related, sympatric vervets (Chlorocebus pygerythrus), and analyzing the nutrient content of the gum of A. drepanolobium and of Crematogaster mimosae, the most common ant species eaten by patas monkeys in Laikipia, Kenya. All occurrences of feeding and moving during focal animal sampling revealed that 1) patas monkeys seek A. drepanolobium gum but vervets avoid it; 2) both species open swollen thorns most often in the morning when antsare less active; 3) patas monkeys continually feed onswollen thorns and gum while moving quickly throughout the day, whereas vervets reduce their consumption of these items and their travel rate at mid-day, and; 4) vervets eat young swollen thorns at a higher rate than patas monkeys. Patas monkeys are able to spend little time acquiring substantial amounts of energy, protein, and minerals from A. drepanolobium gum and C. mimosae ants each day. These findings, when coupled with evidence of causes of infant and adult female mortality, suggest that reproductive success of female patas monkeys is more immediately affected by illness, disease, interactions between adults and infants, and access to water than by food. Copyright © 2012 Wiley Periodicals, Inc.

Effects of new forest management strategies on squirrel populations.

Treesearch

Andrew B. Carey

2000-01-01

Two strategies for managing forests for multiple values have achieved prominence in debates in the Pacific Northwest: (1) legacy retention with passive management and long rotations, and (2) intensive management for timber with commercial thinnings and long rotations. Northern flying squirrels (Glaucomys sabrinus), Townsend's chipmunks (

Green tree frog (Hyla cinerea) and ground squirrel (Xerospermophilus spilosoma) mortality attributed to inland brevetoxin transportation at Padre Island National Seashore, Texas, 2015

USGS Publications Warehouse

Buttke, Danielle E.; Walker, Alicia; Huang, I-Shuo; Flewelling, Leanne; Lankton, Julia S.; Ballmann, Anne E.; Clapp, Travis; Lindsay, James; Zimba, Paul V.

2018-01-01

On 16 September 2015, a red tide (Karenia brevis) bloom impacted coastal areas of Padre Island National Seashore Park. Two days later and about 0.9 km inland, 30–40 adult green tree frogs (Hyla cinerea) were found dead after displaying tremors, weakness, labored breathing, and other signs of neurologic impairment. A rainstorm, accompanied by high winds, rough surf, and high tides, which could have aerosolized brevetoxin, occurred on the morning of the mortality event. Frog carcasses were healthy but contained significant brevetoxin in tissues. Tissue brevetoxin was also found in two dead or dying spotted ground squirrels (Xerospermophilus spilosoma) and a coyote (Canis latrans). Rainwater collected from the location of the mortality event contained brevetoxin. Mortality of green tree frog and ground squirrel mortality has not been previously attributed to brevetoxin exposure and such mortality suggested that inland toxin transport, possibly through aerosols, rainfall, or insects, may have important implications for coastal species.

A test of object permanence in a new-world monkey species, cotton top tamarins (Saguinus oedipus).

PubMed

Neiworth, Julie J; Steinmark, Eric; Basile, Benjamin M; Wonders, Ryann; Steely, Frances; DeHart, Catherine

2003-03-01

Cotton top tamarins were tested in visible and invisible displacement tasks in a method similar to that used elsewhere to test squirrel monkeys and orangutans. All subjects performed at levels significantly above chance on visible ( n=8) and invisible ( n=7) displacements, wherein the tasks included tests of the perseverance error, tests of memory in double and triple displacements, and "catch" trials that tested for the use of the experimenter's hand as a cue for the correct cup. Performance on all nine tasks was significantly higher than chance level selection of cups, and tasks using visible displacements generated more accurate performance than tasks using invisible displacements. Performance was not accounted for by a practice effect based on exposure to successive tasks. Results suggest that tamarins possess stage 6 object permanence capabilities, and that in a situation involving brief exposure to tasks and foraging opportunities, tracking objects' movements and responding more flexibly are abilities expressed readily by the tamarins.

Rhesus monkeys (Macaca mulatta) map number onto space

PubMed Central

Drucker, Caroline B.; Brannon, Elizabeth M.

2014-01-01

Humans map number onto space. However, the origins of this association, and particularly the degree to which it depends upon cultural experience, are not fully understood. Here we provide the first demonstration of a number-space mapping in a non-human primate. We trained four adult male rhesus macaques (Macaca mulatta) to select the fourth position from the bottom of a five-element vertical array. Monkeys maintained a preference to choose the fourth position through changes in the appearance, location, and spacing of the vertical array. We next asked whether monkeys show a spatially-oriented number mapping by testing their responses to the same five-element stimulus array rotated ninety degrees into a horizontal line. In these horizontal probe trials, monkeys preferentially selected the fourth position from the left, but not the fourth position from the right. Our results indicate that rhesus macaques map number onto space, suggesting that the association between number and space in human cognition is not purely a result of cultural experience and instead has deep evolutionary roots. PMID:24762923

Rhesus monkeys (Macaca mulatta) map number onto space.

PubMed

Drucker, Caroline B; Brannon, Elizabeth M

2014-07-01

Humans map number onto space. However, the origins of this association, and particularly the degree to which it depends upon cultural experience, are not fully understood. Here we provide the first demonstration of a number-space mapping in a non-human primate. We trained four adult male rhesus macaques (Macaca mulatta) to select the fourth position from the bottom of a five-element vertical array. Monkeys maintained a preference to choose the fourth position through changes in the appearance, location, and spacing of the vertical array. We next asked whether monkeys show a spatially-oriented number mapping by testing their responses to the same five-element stimulus array rotated ninety degrees into a horizontal line. In these horizontal probe trials, monkeys preferentially selected the fourth position from the left, but not the fourth position from the right. Our results indicate that rhesus macaques map number onto space, suggesting that the association between number and space in human cognition is not purely a result of cultural experience and instead has deep evolutionary roots. Copyright © 2014 Elsevier B.V. All rights reserved.

Anophthalmia in a Wild Eastern Gray Squirrel (Sciurus carolinensis).

PubMed

Rothenburger, Jamie L; Hartnett, Elizabeth A; James, Fiona M K; Grahn, Bruce H

2017-10-01

We describe bilateral true anophthalmia in a juvenile female eastern gray squirrel (Sciurus carolinensis) with histologic confirmation that orbital contents lacked ocular tissues. Additionally, the optic chiasm of the brain was absent and axon density in the optic tract adjacent to the lateral geniculate nucleus was reduced.

Individual acoustic variation in Belding's ground squirrel alarm chirps in the High Sierra Nevada

NASA Astrophysics Data System (ADS)

McCowan, Brenda; Hooper, Stacie L.

2002-03-01

The acoustic structure of calls within call types can vary as function of individual identity, sex, and social group membership and is important in kin and social group recognition. Belding's ground squirrels (Spermophilus beldingi) produce alarm chirps that function in predator avoidance but little is known about the acoustic variability of these alarm chirps. The purpose of this preliminary study was to analyze the acoustic structure of alarm chirps with respect to individual differences (e.g., signature information) from eight Belding's ground squirrels from four different lakes in the High Sierra Nevada. Results demonstrate that alarm chirps are individually distinctive, and that acoustic similarity among individuals may correspond to genetic similarity and thus dispersal patterns in this species. These data suggest, on a preliminary basis, that the acoustic structure of calls might be used as a bioacoustic tool for tracking individuals, dispersal, and other population dynamics in Belding's ground squirrels, and perhaps other vocal species.

The ontogeny of kin-recognition mechanisms in Belding's ground squirrels.

PubMed

Mateo, Jill M

2017-05-01

Despite extensive research on the functions and mechanisms of kin recognition, little is known about developmental changes in the abilities mediating such recognition. Belding's ground squirrels, Urocitellus beldingi, use at least two mechanisms of kin recognition in nepotistic contexts: familiarity and phenotype matching. Because recognition templates develop from early associations with familiar kin (and/or with self), familiarity-based recognition should precede phenotype-matching recognition even though one template is thought to be used for both mechanisms. I used a cross-fostering design to produce individuals that differed in relatedness and familiarity. Two pups (one female and one male) were exchanged reciprocally between two litters within 48-h of birth. Every five days, from 15 to 30-d of age, young were exposed to bedding and oral-gland odors from their familiar foster mother and an unfamiliar unrelated female (familiarity test) and from their unfamiliar genetic mother and another unfamiliar unrelated female (phenotype-matching test). As expected, discrimination of odors based on familiarity was evident at all ages tested, whereas discrimination based on relatedness was not evident until 30-d. My results provide a first estimate for when phenotype-matching mechanisms are used by young Belding's ground squirrels, and thus when they can recognize unfamiliar kin such as older sisters or grandmothers. Belding's ground squirrels are the first species for which the development of the production, perception and action components is well understood. Copyright © 2017 Elsevier Inc. All rights reserved.

Consideration of other primate species as flight animals

NASA Technical Reports Server (NTRS)

Bourne, G. H.

1977-01-01

The different types of primates which might be used as flight animals are surveyed, and the pros and cons of using them are discussed. Various factors suggest that the most desirable animals for space studies are the rhesus, pig-tailed, Java, and squirrel monkeys. The capuchin monkey has assets for certain types of space experimentation.

Catenotaenia dendritica (Cestoda: Catenotaeniidae) and Three Ectoparasite Species in the Red Squirrel, Sciurus vulgaris, from Cheongju, Korea

PubMed Central

Choe, Seongjun; Lee, Dongmin; Park, Hansol; Jeon, Hyeong-Kyu; Lee, Youngsun; Na, Ki-Jeong; Lee, In-Yong; Eom, Keeseon S.

2016-01-01

Parasites are recorded from the red squirrel, Sciurus vulgaris, from Cheongju, the Republic of Korea. A total of 5 road-killed squirrels were thoroughly examined for internal and external parasites from November 2011 to May 2014. Total 4 parasite species, including 1 tapeworm and 3 ectoparasite species were recovered. They were morphologically identified as Catenotaenia dendritica (Cestoda: Catenotaeniidae), Hirstionyssus sciurinus, Leptotrombidium pallidum, and Ceratophyllus (Monopsyllus) indages. Among them, C. dendritica and H. sciurinus are recorded for the first time in the Korean parasite fauna. In addition, the possibility that the red squirrel could act as a reservoir host for a zoonotic disease like tsutsugamushi disease with L. pallidum as its vector has been raised. PMID:27658604

Catenotaenia dendritica (Cestoda: Catenotaeniidae) and Three Ectoparasite Species in the Red Squirrel, Sciurus vulgaris, from Cheongju, Korea.

PubMed

Choe, Seongjun; Lee, Dongmin; Park, Hansol; Jeon, Hyeong-Kyu; Lee, Youngsun; Na, Ki-Jeong; Lee, In-Yong; Eom, Keeseon S

2016-08-01

Parasites are recorded from the red squirrel, Sciurus vulgaris, from Cheongju, the Republic of Korea. A total of 5 road-killed squirrels were thoroughly examined for internal and external parasites from November 2011 to May 2014. Total 4 parasite species, including 1 tapeworm and 3 ectoparasite species were recovered. They were morphologically identified as Catenotaenia dendritica (Cestoda: Catenotaeniidae), Hirstionyssus sciurinus, Leptotrombidium pallidum, and Ceratophyllus (Monopsyllus) indages. Among them, C. dendritica and H. sciurinus are recorded for the first time in the Korean parasite fauna. In addition, the possibility that the red squirrel could act as a reservoir host for a zoonotic disease like tsutsugamushi disease with L. pallidum as its vector has been raised.

Capuchin monkeys (Cebus apella) treat small and large numbers of items similarly during a relative quantity judgment task.

PubMed

Beran, Michael J; Parrish, Audrey E

2016-08-01

A key issue in understanding the evolutionary and developmental emergence of numerical cognition is to learn what mechanism(s) support perception and representation of quantitative information. Two such systems have been proposed, one for dealing with approximate representation of sets of items across an extended numerical range and another for highly precise representation of only small numbers of items. Evidence for the first system is abundant across species and in many tests with human adults and children, whereas the second system is primarily evident in research with children and in some tests with non-human animals. A recent paper (Choo & Franconeri, Psychonomic Bulletin & Review, 21, 93-99, 2014) with adult humans also reported "superprecise" representation of small sets of items in comparison to large sets of items, which would provide more support for the presence of a second system in human adults. We first presented capuchin monkeys with a test similar to that of Choo and Franconeri in which small or large sets with the same ratios had to be discriminated. We then presented the same monkeys with an expanded range of comparisons in the small number range (all comparisons of 1-9 items) and the large number range (all comparisons of 10-90 items in 10-item increments). Capuchin monkeys showed no increased precision for small over large sets in making these discriminations in either experiment. These data indicate a difference in the performance of monkeys to that of adult humans, and specifically that monkeys do not show improved discrimination performance for small sets relative to large sets when the relative numerical differences are held constant.

2. Light tower, view west towards Squirrel Island, south and ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. Light tower, view west towards Squirrel Island, south and east sides - Ram Island Light Station, Ram Island, south of Ocean Point & just north of Fisherman Island, marking south side of Fisherman Island Passage, Ocean Point, Lincoln County, ME

Blockade of THC-seeking behavior and relapse in monkeys by the cannabinoid CB(1)-receptor antagonist rimonabant.

PubMed

Justinova, Zuzana; Munzar, Patrik; Panlilio, Leigh V; Yasar, Sevil; Redhi, Godfrey H; Tanda, Gianluigi; Goldberg, Steven R

2008-11-01

Accumulating evidence suggests the endocannabinoid system modulates environmental cues' ability to induce seeking of drugs, including nicotine and alcohol. However, little attention has been directed toward extending these advances to the growing problem of cannabis use disorders. Therefore, we studied intravenous self-administration of Delta(9)-tetrahydrocannabinol (THC), the main psychoactive constituent of marijuana, using a second-order schedule of drug seeking. Squirrel monkeys' lever responses produced only a brief cue light until the end of the session, when the final response delivered THC along with the cue. When a reinstatement procedure was used to model relapse following a period of abstinence, THC-seeking behavior was robustly reinstated by the cue or by pre-session administration of THC, other cannabinoid agonists, or morphine, but not cocaine. The cannabinoid antagonist rimonabant blocked cue-induced drug seeking, THC-induced drug seeking, and the direct reinforcing effects of THC. Thus, rimonabant and related medications might be effective as treatments for cannabinoid dependence.

Early Rockets

NASA Image and Video Library

1959-05-28

On May 28, 1959, a Jupiter Intermediate Range Ballistic Missile provided by a U.S. Army team in Redstone Arsenal, Alabama, launched a nose cone carrying Baker, A South American squirrel monkey and Able, An American-born rhesus monkey. This photograph shows Able after recovery of the nose cone of the Jupiter rocket by U.S.S. Kiowa.

Stimulus Similarity and Encoding Time Influence Incidental Recognition Memory in Adult Monkeys with Selective Hippocampal Lesions

ERIC Educational Resources Information Center

Zeamer, Alyson; Meunier, Martine; Bachevalier, Jocelyne

2011-01-01

Recognition memory impairment after selective hippocampal lesions in monkeys is more profound when measured with visual paired-comparison (VPC) than with delayed nonmatching-to-sample (DNMS). To clarify this issue, we assessed the impact of stimuli similarity and encoding duration on the VPC performance in monkeys with hippocampal lesions and…

Predictive habitat models derived from nest-box occupancy for the endangered Carolina northern flying squirrel in the southern Appalachians

Treesearch

W. Mark Ford; Andrew M. Evans; Richard H. Odom; Jane L. Rodrigue; Christine A. Kelly; Nicole Abaid; Corinne A. Diggins; Douglas Newcomb

2015-01-01

In the southern Appalachians, artificial nest-boxes are used to survey for the endangered Carolina northern flying squirrel (CNFS; Glaucomys sabrinus coloratus), a disjunct subspecies associated with high elevation (>1385 m) forests. Using environmental parameters diagnostic of squirrel habitat, we created 35 a priori occupancy...

Impact of Striped-Squirrel Nectar-Robbing Behaviour on Gender Fitness in Alpinia roxburghii Sweet (Zingiberaceae).

PubMed

Deng, Xiaobao; Mohandass, Dharmalingam; Katabuchi, Masatoshi; Hughes, Alice C; Roubik, David W

2015-01-01

Nectar-robbing has the potential to strongly affect male and female reproductive fitness of plants. One example of nectar theft is that shown by striped-squirrels (Tamiops swinhoei) on a number of ginger species, including Alpinia roxburghii and A. kwangsiensis (Zingiberaceae). In this study, we used a fluorescent dye as a pollen analogue, and measured fruit and seed output, to test the effect of squirrel nectar-robbing on A. roxburghii reproductive fitness. Pollen transfer between robbed and unrobbed flowers was assessed by comparing 60 randomly established plots containing robbed and unrobbed flowers. The frequency of squirrel robbing visits and broken styles were recorded from a number of flowers for five consecutive days. Two bee species (Bombus eximius and Apis cerana), were the primary pollinators, and their visitation frequency was recorded for six consecutive days. The results showed that fluorescent powder from unrobbed flowers was dispersed further, and to a greater number of flowers than that placed on robbed flowers. Additionally, robbing flowers caused significant damage to reproductive organs, resulting in lower fruit and seed sets in robbed than in unrobbed flowers and influencing both male and female fitness. The frequency of the primary pollinator visits (B. eximius) was significantly higher for unrobbed plants than for robbed plants. The present study clearly shows the negative impact of squirrel robbing on A. roxburghii male reproductive fitness and neutral impact on female reproductive fitness.

Comparison of surface temperature in 13-lined ground squirrel (Spermophilus tridecimlineatus) and yellow-bellied marmot (Marmota flaviventris) during arousal from hibernation.

PubMed

Phillips, P K; Heath, J E

2004-08-01

Surface temperatures (Ts) of eight 13-lined ground squirrels and seven yellow-bellied marmots were measured during arousal from hibernation using infrared thermography (IRT) and recorded on videotape. Animals aroused normally in 5 degrees C cold rooms. Body temperatures were recorded during arousal using both cheek pouch and interscapular temperature probes. Warming rate in arousal was exponential. Mean mass specific warming rates show the squirrels warm faster (69.76 degrees C/h/kg) than the marmots (4.49 degrees C/h/kg). Surface temperatures (Ts) for 11 regions were measured every few minutes during arousal. The smaller ground squirrel shows the ability to perfuse distal regions without compromising rise in deep body temperature (Tb). All squirrel Ts's remained low as Tb rose to 18 degrees C, at which point, eyes opened, squirrels became more active and all Ts's rose parallel to Tb. Marmot Ts remained low as Tb rose initially. Each marmot showed a plateau phase where Tb remained constant (mean Tb 20.3+/-1.0 degrees C, duration 9.4+/-4.1 min) during which time all Ts's rose, and then remained relatively constant as Tb again began to rise. An anterior to posterior Ts gradient was evident in the ground squirrel, both body and feet. This gradient was only evident in the feet of the marmots.

Habitat associations of hypogeous fungi in the Southern Appalachians: implications for the endangered northern flying squirrel (Glaycomys sabrinus coloratus)

Treesearch

Susan C. Loeb; Frank H. Tainter; Efren Cázares

2000-01-01

Sporocarps of hypogeous mycorrhizal fungi (truffles) are the major food of northern flying squirrels (Glaucomys sabrinus). The two subspecies of northern flying squirrels that occur in the southern Appalachians, G. s. coloratus and G. s. fuscus, are endangered species which are primarily found in the ecotone...

Biology and management of the western gray squirrel and Oregon white oak woodlands: with emphasis on the Puget Trough.

Treesearch

L.A. Ryan; A.B. Carey

1995-01-01

The western gray squirrel (Sciurus griseus Ord, 1818) has been accorded "threatened species" status by the state of Washington. populations are small, scattered, and declining primarily due to the loss and fragmentation of suitable habitat. Western gray squirrels are closely associated with Oregon white oak (Quercus garryana...

Effects of low temperature on breathing pattern and ventilatory responses during hibernation in the golden-mantled ground squirrel.

PubMed

Webb, Cheryl L; Milsom, William K

2017-07-01

During entrance into hibernation in golden-mantled ground squirrels (Callospermophilus lateralis), ventilation decreases as metabolic rate and body temperature fall. Two patterns of respiration occur during deep hibernation. At 7 °C body temperature (T b ), a breathing pattern characterized by episodes of multiple breaths (20.6 ± 1.9 breaths/episode) separated by long apneas or nonventilatory periods (T nvp ) (mean = 11.1 ± 1.2 min) occurs, while at 4 °C T b , a pattern in which breaths are evenly distributed and separated by a relatively short T nvp (0.5 ± 0.05 min) occurs. Squirrels exhibiting each pattern have similar metabolic rates and levels of total ventilation (0.2 and 0.23 ml O 2 /hr/kg and 0.11 and 0.16 ml air/min/kg, respectively). Squirrels at 7 °C T b exhibit a significant hypoxic ventilatory response, while squirrels at 4 °C T b do not respond to hypoxia at any level of O 2 tested. Squirrels at both temperatures exhibit a significant hypercapnic ventilatory response, but the response is significantly reduced in the 4 °C T b squirrels. Carotid body denervation has little effect on the breathing patterns or on the hypercapnic ventilatory responses. It does reduce the magnitude and threshold for the hypoxic ventilatory response. Taken together the data suggest that (1) the fundamental rhythm generator remains functional at low temperatures; (2) the hypercapnic ventilatory response arises from central chemoreceptors that remain functional at very low temperatures; (3) the hypoxic ventilatory response arises from both carotid body and aortic chemoreceptors that are silenced at lower temperatures; and (4) there is a strong correlation between breathing pattern and chemosensitivity.

EVIDENCE FOR MOTOR PLANNING IN MONKEYS: RHESUS MACAQUES SELECT EFFICIENT GRIPS WHEN TRANSPORTING SPOONS

PubMed Central

Nelson, Eliza L.; Berthier, Neil E.; Metevier, Christina M.; Novak, Melinda A.

2014-01-01

McCarty and colleagues (1999) developed the elevated spoon task to measure motor planning in human infants. In this task, a spoon containing food was placed on an elevated apparatus that supported both ends of the spoon. The handle was oriented to the left or right on different trials. We presented naïve adult rhesus monkeys (Macaca mulatta) with the elevated spoon problem, and observed how monkeys learned the affordances of spoons over sessions. Strikingly, monkeys developed two different strategies for efficient spoon transport in just 12 to 36 trials. In subsequent testing with a novel double bowl spoon approximately 1 year later, monkeys demonstrated that they were attending to the baited spoon bowl and continued to select efficient grips for transporting the spoon. Monkey data were contrasted with previous studies in human infants using a perception-action perspective in an effort to understand the fundamentals of tool use and motor planning that may be common in the development of these abilities across species and their origins in human behavior. PMID:21676101

Mapping and monitoring Mount Graham red squirrel habitat with Lidar and Landsat imagery

USGS Publications Warehouse

Hatten, James R.

2014-01-01

The Mount Graham red squirrel (Tamiasciurus hudsonicus grahamensis) is an endemic subspecies located in the Pinaleño Mountains of southeast Arizona. Living in a conifer forest on a sky-island surrounded by desert, the Mount Graham red squirrel is one of the rarest mammals in North America. Over the last two decades, drought, insect infestations, and fire destroyed much of its habitat. A federal recovery team is working on a plan to recover the squirrel and detailed information is necessary on its habitat requirements and population dynamics. Toward that goal I developed and compared three probabilistic models of Mount Graham red squirrel habitat with a geographic information system and logistic regression. Each model contained the same topographic variables (slope, aspect, elevation), but the Landsat model contained a greenness variable (Normalized Difference Vegetation Index) extracted from Landsat, the Lidar model contained three forest-inventory variables extracted from lidar, while the Hybrid model contained Landsat and lidar variables. The Hybrid model produced the best habitat classification accuracy, followed by the Landsat and Lidar models, respectively. Landsat-derived forest greenness was the best predictor of habitat, followed by topographic (elevation, slope, aspect) and lidar (tree height, canopy bulk density, and live basal area) variables, respectively. The Landsat model's probabilities were significantly correlated with all 12 lidar variables, indicating its utility for habitat mapping. While the Hybrid model produced the best classification results, only the Landsat model was suitable for creating a habitat time series or habitat–population function between 1986 and 2013. The techniques I highlight should prove valuable in the development of Landsat- or lidar-based habitat models range wide.

Oblique effect in visual area 2 of macaque monkeys

PubMed Central

Shen, Guofu; Tao, Xiaofeng; Zhang, Bin; Smith, Earl L.; Chino, Yuzo M.

2014-01-01

The neural basis of an oblique effect, a reduced visual sensitivity for obliquely oriented stimuli, has been a matter of considerable debate. We have analyzed the orientation tuning of a relatively large number of neurons in the primary visual cortex (V1) and visual area 2 (V2) of anesthetized and paralyzed macaque monkeys. Neurons in V2 but not V1 of macaque monkeys showed clear oblique effects. This orientation anisotropy in V2 was more robust for those neurons that preferred higher spatial frequencies. We also determined whether V1 and V2 neurons exhibit a similar orientation anisotropy soon after birth. The oblique effect was absent in V1 of 4- and 8-week-old infant monkeys, but their V2 neurons showed a significant oblique effect. This orientation anisotropy in infant V2 was milder than that in adults. The results suggest that the oblique effect emerges in V2 based on the pattern of the connections that are established before birth and enhanced by the prolonged experience-dependent modifications of the neural circuitry in V2. PMID:24511142

A Squirrel Cage Type Electric Motor Rotor Assembly.

DTIC Science & Technology

1996-09-05

cage motor, but also provides efficiencies approaching those of permanent magnet motors . With the above and other objects in view, as will...and active motor life relative to known permanent magnet motors . Referring to FIG. 4, there is illustrated an alternative embodiment in which...part the.known advantages of a squirrel cage motor, and further provides improved efficiencies approaching those of permanent magnet motors . It is to

Animal studies on Spacelab-3

NASA Technical Reports Server (NTRS)

Schatte, C.; Grindeland, R.; Callahan, P.; Berry, W.; Funk, G.; Lencki, W.

1987-01-01

The flight of two squirrel monkeys and 24 rats on Spacelab-3 was the first mission to provide hands-on maintenance on animals in a laboratory environment. With few exceptions, the animals grew and behaved normally, were free of chronic stress, and differed from ground controls only for gravity dependent parameters. One of the monkeys exhibited symptoms of space sickness similar to those observed in humans, which suggests squirrel monkeys may be good models for studying the space adaptation syndrome. Among the wide variety of parameters measured in the rats, most notable was the dramatic loss of muscle mass and increased fragility of long bones. Other interesting rat findings were those of suppressed interferom production by spleen cells, defective release of growth hormone by somatrophs, possible dissociation of circadian pacemakers, changes in hepatic lipid and carbohydrate metabolism, and hypersensitivity of marrow cells to erythropoietin. These results portend a strong role for animals in identifying and elucidating the physiological and anatomical responses of mammals to microgravity.

Animal studies on Spacelab-3

NASA Technical Reports Server (NTRS)

Schatte, C.; Grindeland, R.; Callahan, P.; Funk, G.; Lencki, W.; Berry, W.

1986-01-01

The flight of two squirrel monkeys and 24 rates on Spacelab-3 was the first mission to provide hand-on maintenance on animals in a laboratory environment. With few exceptions, the animals grew and behaved normally, were free of chronic stress, and differed from ground controls only for gravity-dependent parameters. One of the monkeys exhibited symptoms of space sickness similar to those observed in humans, which suggests squirrel monkeys may be good models for studying the space-adaptation syndrome. Among the wide variety of parameters measured in the rats, most notable was the dramatic loss of muscle mass and increased fragility of long bones. Other interesting rat findings were those of suppressed interferon production by spleen cells, defective release of growth hormone by somatotrophs, possible dissociation of circadian pacemakers, changes in hepatic lipid and carbohydrate metabolism, and hypersensitivity of marrow cells to erythopoietin. These results portend a strong role for animals in identifying and elucidating the physiological and anatomical responses of mammals to microgravity.

Differences in trapping mortality rates of northern flying squirrels

Treesearch

D.K. Rosenberg; R.G. Anthony

1993-01-01

We described trapping mortality rates of northern flying squirrel (Glaucomys sabrinus) populations in western Oregon, U.S.A., and evaluated the effects of sex, age, body mass, and number of times an individual was recaptured on these rates. Although the overall trapping mortality rates were relatively low (7%) during 16-21 day trapping sessions, we...

A multidimensional model of the effect of gravity on the spatial orientation of the monkey

NASA Technical Reports Server (NTRS)

Merfeld, D. M.; Young, L. R.; Oman, C. M.; Shelhamer, M. J.

1993-01-01

A "sensory conflict" model of spatial orientation was developed. This mathematical model was based on concepts derived from observer theory, optimal observer theory, and the mathematical properties of coordinate rotations. The primary hypothesis is that the central nervous system of the squirrel monkey incorporates information about body dynamics and sensory dynamics to develop an internal model. The output of this central model (expected sensory afference) is compared to the actual sensory afference, with the difference defined as "sensory conflict." The sensory conflict information is, in turn, used to drive central estimates of angular velocity ("velocity storage"), gravity ("gravity storage"), and linear acceleration ("acceleration storage") toward more accurate values. The model successfully predicts "velocity storage" during rotation about an earth-vertical axis. The model also successfully predicts that the time constant of the horizontal vestibulo-ocular reflex is reduced and that the axis of eye rotation shifts toward alignment with gravity following postrotatory tilt. Finally, the model predicts the bias, modulation, and decay components that have been observed during off-vertical axis rotations (OVAR).

The neonatal marmoset monkey ovary is very primitive exhibiting many oogonia

PubMed Central

Fereydouni, B; Drummer, C; Aeckerle, N; Schlatt, S; Behr, R

2014-01-01

Oogonia are characterized by diploidy and mitotic proliferation. Human and mouse oogonia express several factors such as OCT4, which are characteristic of pluripotent cells. In human, almost all oogonia enter meiosis between weeks 9 and 22 of prenatal development or undergo mitotic arrest and subsequent elimination from the ovary. As a consequence, neonatal human ovaries generally lack oogonia. The same was found in neonatal ovaries of the rhesus monkey, a representative of the old world monkeys (Catarrhini). By contrast, proliferating oogonia were found in adult prosimians (now called Strepsirrhini), which is a group of ‘lower’ primates. The common marmoset monkey (Callithrix jacchus) belongs to the new world monkeys (Platyrrhini) and is increasingly used in reproductive biology and stem cell research. However, ovarian development in the marmoset monkey has not been widely investigated. Herein, we show that the neonatal marmoset ovary has an extremely immature histological appearance compared with the human ovary. It contains numerous oogonia expressing the pluripotency factors OCT4A, SALL4, and LIN28A (LIN28). The pluripotency factor-positive germ cells also express the proliferation marker MKI67 (Ki-67), which has previously been shown in the human ovary to be restricted to premeiotic germ cells. Together, the data demonstrate the primitiveness of the neonatal marmoset ovary compared with human. This study may introduce the marmoset monkey as a non-human primate model to experimentally study the aspects of primate primitive gonad development, follicle assembly, and germ cell biology in vivo. PMID:24840529

Nutritional Findings and Early Behavioral Observations.

ERIC Educational Resources Information Center

Ausman, Lynn M.

This study investigated the effects of a short period of severe protein malnutrition on subsequent growth and development in the squirrel monkey. A total of 12 newborn monkeys were fed a low protein diet from 2 to 8 weeks of age then rehabilitated by returning them to the 13 percent protein diet of the control group. Minimum amount of protein…

Thymus development in Macaca fascicularis (Cynomolgus monkey): an approach for toxicology and embryology.

PubMed

Buse, Eberhard; Habermann, Gunnar; Vogel, Friedhelm

2006-05-01

Thymus development was studied in the cynomolgus monkey from day 35 of gestation (gd 35) to the stage of advanced involution in a 21-year-old monkey. Special emphasis was placed on thymus cell generation and cellular pattern formation. At gd 35, the epithelial bud of the thymus was visible in a sagittal position at the level of the thoracic aperture. At gd 50, first lymphocyte-like cells and few Human Leukocyte Antigen-D Region (HLA-DR) immunoreactive cells appeared. The cortico-medullary differentiation, Hassall's body precursors and faint immunoreactivity for T-lymphocytes (CD 3-positive) were detected from gd 60 onwards. First macrophages (CD 68 positive) were apparent at day 70, first CD 20 immunoreactive cells (B-lymphocyte-like cells) at gd 85, and natural killer cells (M1014 immunoreactive) at gd 100. At gd 100 all evaluated cell populations present in the adult cynomolgus monkey thymus were in place, whereas no B- and T-cell precursors or (CD 34 and CD 117, respectively) dendritic cells (CD 35 positive cells) were present. All these immunopositive cells persisted, partly with changing distribution patterns, until the advanced age of 21 years with the exception of natural killer cells, which were present only until adult ages (evaluation at 4-7 years). The rationale of this study was to analyse thymic development in the cynomolgus monkey and to evaluate the relevance of the development of thymus in non-human primate as a model for corresponding human targeted toxicological research.

Development of a rhesus monkey lung geometry model and application to particle deposition in comparison to humans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asgharian, Bahman; Price, Owen; McClellan, Gene

2012-11-01

The exposure-dose-response characterization of an inhalation hazard established in an animal species needs to be translated to an equivalent characterization in humans relative to comparable doses or exposure scenarios. Here, the first geometry model of the conducting airways for rhesus monkeys is developed based upon CT images of the conducting airways of a 6-month-old male, rhesus monkey. An algorithm was developed for adding the alveolar region airways using published rhesus morphometric data. The resultant lung geometry model can be used in mechanistic particle or gaseous dosimetry models. Such dosimetry models require estimates of the upper respiratory tract volume of themore » animal and the functional residual capacity, as well as of the tidal volume and breathing frequency of the animal. The relationship of these variables to rhesus monkeys of differing body weights was established by synthesizing and modeling published data as well as modeling pulmonary function measurements on 121 rhesus control animals. Deposition patterns of particles up to 10 µm in size were examined for endotracheal and and up to 5 µm for spontaneous breathing in infant and young adult monkeys and compared to those for humans. Deposition fraction of respirable size particles was found to be higher in the conducting airways of infant and young adult rhesus monkeys compared to humans. Due to the filtering effect of the conducting airways, pulmonary deposition in rhesus monkeys was lower than that in humans. Finally, future research areas are identified that would either allow replacing assumptions or improving the newly developed lung model.« less

Development of a rhesus monkey lung geometry model and application to particle deposition in comparison to humans

PubMed Central

Asgharian, Bahman; Price, Owen; McClellan, Gene; Corley, Rick; Einstein, Daniel R.; Jacob, Richard E.; Harkema, Jack; Carey, Stephan A.; Schelegle, Edward; Hyde, Dallas; Kimbell, Julia S.; Miller, Frederick J.

2016-01-01

The exposure-dose-response characterization of an inhalation hazard established in an animal species needs to be translated to an equivalent characterization in humans relative to comparable doses or exposure scenarios. Here, the first geometry model of the conducting airways for rhesus monkeys is developed based upon CT images of the conducting airways of a 6-month-old male, rhesus monkey. An algorithm was developed for adding the alveolar region airways using published rhesus morphometric data. The resultant lung geometry model can be used in mechanistic particle or gaseous dosimetry models. Such dosimetry models require estimates of the upper respiratory tract volume of the animal and the functional residual capacity, as well as of the tidal volume and breathing frequency of the animal. The relationship of these variables to rhesus monkeys of differing body weights was established by synthesizing and modeling published data as well as modeling pulmonary function measurements on 121 rhesus control animals. Deposition patterns of particles up to 10 μm in size were examined for endotracheal and and up to 5 μm for spontaneous breathing in infant and young adult monkeys and compared to those for humans. Deposition fraction of respirable size particles was found to be higher in the conducting airways of infant and young adult rhesus monkeys compared to humans. Due to the filtering effect of the conducting airways, pulmonary deposition in rhesus monkeys was lower than that in humans. Future research areas are identified that would either allow replacing assumptions or improving the newly developed lung model. PMID:23121298

Impact of Striped-Squirrel Nectar-Robbing Behaviour on Gender Fitness in Alpinia roxburghii Sweet (Zingiberaceae)

PubMed Central

Deng, Xiaobao; Mohandass, Dharmalingam; Katabuchi, Masatoshi; Hughes, Alice C.; Roubik, David W.

2015-01-01

Nectar-robbing has the potential to strongly affect male and female reproductive fitness of plants. One example of nectar theft is that shown by striped-squirrels (Tamiops swinhoei) on a number of ginger species, including Alpinia roxburghii and A. kwangsiensis (Zingiberaceae). In this study, we used a fluorescent dye as a pollen analogue, and measured fruit and seed output, to test the effect of squirrel nectar-robbing on A. roxburghii reproductive fitness. Pollen transfer between robbed and unrobbed flowers was assessed by comparing 60 randomly established plots containing robbed and unrobbed flowers. The frequency of squirrel robbing visits and broken styles were recorded from a number of flowers for five consecutive days. Two bee species (Bombus eximius and Apis cerana), were the primary pollinators, and their visitation frequency was recorded for six consecutive days. The results showed that fluorescent powder from unrobbed flowers was dispersed further, and to a greater number of flowers than that placed on robbed flowers. Additionally, robbing flowers caused significant damage to reproductive organs, resulting in lower fruit and seed sets in robbed than in unrobbed flowers and influencing both male and female fitness. The frequency of the primary pollinator visits (B. eximius) was significantly higher for unrobbed plants than for robbed plants. The present study clearly shows the negative impact of squirrel robbing on A. roxburghii male reproductive fitness and neutral impact on female reproductive fitness. PMID:26689684

The connections of layer 4 subdivisions in the primary visual cortex (V1) of the owl monkey.

PubMed

Boyd, J D; Mavity-Hudson, J A; Casagrande, V A

2000-07-01

with connectional data in other primates. Re-examination of data from previous studies in squirrel and macaque monkeys suggests that the tripartite organization of layer 4 and the unique projection pattern of layer 4ctr are not restricted to owl monkeys, but are common to a number of primate species.

Genome Editing of Monkey.

PubMed

Liu, Zhen; Cai, Yijun; Sun, Qiang

2017-01-01

Gene-modified monkey models would be particularly valuable in biomedical and neuroscience research. Virus-based transgenic and programmable nucleases-based site-specific gene editing methods (TALEN, CRISPR-cas9) enable the generation of gene-modified monkeys with gain or loss of function of specific genes. Here, we describe the generation of transgenic and knock-out (KO) monkeys with high efficiency by lentivirus and programmable nucleases.

The elusive illusion: Do children (Homo sapiens) and capuchin monkeys (Cebus apella) see the Solitaire illusion?

PubMed

Parrish, Audrey E; Agrillo, Christian; Perdue, Bonnie M; Beran, Michael J

2016-02-01

One approach to gaining a better understanding of how we perceive the world is to assess the errors that human and nonhuman animals make in perceptual processing. Developmental and comparative perspectives can contribute to identifying the mechanisms that underlie systematic perceptual errors often referred to as perceptual illusions. In the visual domain, some illusions appear to remain constant across the lifespan, whereas others change with age. From a comparative perspective, many of the illusions observed in humans appear to be shared with nonhuman primates. Numerosity illusions are a subset of visual illusions and occur when the spatial arrangement of stimuli within a set influences the perception of quantity. Previous research has found one such illusion that readily occurs in human adults, the Solitaire illusion. This illusion appears to be less robust in two monkey species, rhesus macaques and capuchin monkeys. We attempted to clarify the ontogeny of this illusion from a developmental and comparative perspective by testing human children and task-naïve capuchin monkeys in a computerized quantity judgment task. The overall performance of the monkeys suggested that they perceived the numerosity illusion, although there were large differences among individuals. Younger children performed similarly to the monkeys, whereas older children more consistently perceived the illusion. These findings suggest that human-unique perceptual experiences with the world might play an important role in the emergence of the Solitaire illusion in human adults, although other factors also may contribute. Copyright © 2015 Elsevier Inc. All rights reserved.

Severely insect-damaged forest: A temporary trap for red squirrels?

Treesearch

Claire A. Zugmeyer; John L. Koprowski

2009-01-01

Recent insect infestations in the spruce-fir forest in the Pinalenno Mountains of southeastern Arizona provided an opportunity to document response to severe forest disturbance and existence of an ecological trap for an endemic montane isolate, the endangered Mt. Graham red squirrel (Tamiasciurus hudsonicus grahamensis). From September 2003 to...

Conservatism and Adaptability during Squirrel Radiation: What Is Mandible Shape Telling Us?

PubMed Central

Casanovas-Vilar, Isaac; van Dam, Jan

2013-01-01

Both functional adaptation and phylogeny shape the morphology of taxa within clades. Herein we explore these two factors in an integrated way by analyzing shape and size variation in the mandible of extant squirrels using landmark-based geometric morphometrics in combination with a comparative phylogenetic analysis. Dietary specialization and locomotion were found to be reliable predictors of mandible shape, with the prediction by locomotion probably reflecting the underlying diet. In addition a weak but significant allometric effect could be demonstrated. Our results found a strong phylogenetic signal in the family as a whole as well as in the main clades, which is in agreement with the general notion of squirrels being a conservative group. This fact does not preclude functional explanations for mandible shape, but rather indicates that ancient adaptations kept a prominent role, with most genera having diverged little from their ancestral clade morphologies. Nevertheless, certain groups have evolved conspicuous adaptations that allow them to specialize on unique dietary resources. Such adaptations mostly occurred in the Callosciurinae and probably reflect their radiation into the numerous ecological niches of the tropical and subtropical forests of Southeastern Asia. Our dietary reconstruction for the oldest known fossil squirrels (Eocene, 36 million years ago) show a specialization on nuts and seeds, implying that the development from protrogomorphous to sciuromorphous skulls was not necessarily related to a change in diet. PMID:23593456

A MEG investigation of somatosensory processing in the rhesus monkey

PubMed Central

Wilson, Tony W.; Godwin, Dwayne W.; Czoty, Paul W.; Nader, Michael A.; Kraft, Robert A.; Buchheimer, Nancy C.; Daunais, James B.

2009-01-01

The use of minimally and non-invasive neuroimaging methods in animal models has sharply increased over the past decade. Such studies have enhanced understanding of the neural basis of the physical signals quantified by these tools, and have addressed an assortment of fundamental and otherwise intractable questions in neurobiology. To date, these studies have almost exclusively utilized positron-emission tomography or variants of magnetic resonance based imaging. These methods provide largely indirect measures of brain activity and are strongly reliant on intact vasculature and normal blood flow, which is known to be compromised in many clinical conditions. The current study provides the first demonstration of whole-head magnetoencephalography (MEG), a non-invasive and direct measure of neuronal activity, in a rhesus monkey, and in the process supplies the initial data on systems-level dynamics in somatosensory cortices. An adult rhesus monkey underwent three separate studies of tactile stimulation on the pad of the right second or fifth digit as whole-head MEG data were acquired. The neural generators of the primary neuromagnetic components were localized using an equivalent-current-dipole model. Second digit stimulation produced an initial cortical response peaking ∼16 ms after stimulus onset in the contralateral somatosensory cortices, with a later response at ∼96 ms in an overlapping or nearby neural area with a roughly orthogonal orientation. Stimulation of the fifth digit produced similar results, the main exception being a substantially weaker later response. We believe the 16ms response is likely the monkey homologue of the human M50 response, as both are the earliest cortical response and localize to the contralateral primary somatosensory area. Thus, these data suggest that mechanoreception in nonhuman primates operates substantially faster than that in adult humans. More broadly, these results demonstrate that it is feasible to use current human whole

Irregular xenoantibodies against human red blood cells in Papio anubis, P ursinus, P hamadryas, P papio, Saimiri sciureus, and Macaca mulatta: possible effect on xenotransplantation results.

PubMed

Ramis, G; Martínez-Alarcón, L; Majado, M; Ríos, A; Quereda, J J; Ramírez, P; Muñoz, A

2010-01-01

To assess the presence of irregular xenoantibodies against human red blood cells (RBCs) in 6 primate species used in xenotransplantation and other experimental procedures. Serum samples from 109 baboons of 4 different species (olive, chacma, sacred, and Guinea), 38 rhesus macaques, and 30 squirrel monkeys were tested for irregular xenoantibodies using an agglutination test using human RBCs of known phenotype for Rh, Kell, Kidd, Lewis, Lutheran, P1, and Duffy antigens, commercially available as RBC I, II, and III. We found hemagglutination for RBC I in 49%, 22%, 100%, 57%, 32%, and 33% of olive, chacma, sacred, and Guinea baboons, rhesus macaques, and squirrel monkey, respectively. The frequency for RBC II was 49%, 50%, 100%, 57%, 37%, and 33%, respectively, and for RBC III was 56%, 37%, 100%, 79%, 34%, and 33%, respectively. There were differences in frequency depending on the sex of the rhesus macaques; all 3 RBCs tested were higher in the females: 44% vs 0%, P = .008; 48% vs 1%, P = .02, and 44% vs 9.1%, P = .04 for RBC I, II, and III, respectively. There were differences due to age in only olive baboons, and a higher frequency in younger animals compared with juvenile, subadult, and adult animals for all 3 human RBCs. Assessment of irregular antibodies in the presence of primate serum should be taken into account during any experimental xenotransplantation protocol.

Stress amplifies sex differences in primate prefrontal profiles of gene expression.

PubMed

Lee, Alex G; Hagenauer, Megan; Absher, Devin; Morrison, Kathleen E; Bale, Tracy L; Myers, Richard M; Watson, Stanley J; Akil, Huda; Schatzberg, Alan F; Lyons, David M

2017-11-02

Stress is a recognized risk factor for mood and anxiety disorders that occur more often in women than men. Prefrontal brain regions mediate stress coping, cognitive control, and emotion. Here, we investigate sex differences and stress effects on prefrontal cortical profiles of gene expression in squirrel monkey adults. Dorsolateral, ventrolateral, and ventromedial prefrontal cortical regions from 18 females and 12 males were collected after stress or no-stress treatment conditions. Gene expression profiles were acquired using HumanHT-12v4.0 Expression BeadChip arrays adapted for squirrel monkeys. Extensive variation between prefrontal cortical regions was discerned in the expression of numerous autosomal and sex chromosome genes. Robust sex differences were also identified across prefrontal cortical regions in the expression of mostly autosomal genes. Genes with increased expression in females compared to males were overrepresented in mitogen-activated protein kinase and neurotrophin signaling pathways. Many fewer genes with increased expression in males compared to females were discerned, and no molecular pathways were identified. Effect sizes for sex differences were greater in stress compared to no-stress conditions for ventromedial and ventrolateral prefrontal cortical regions but not dorsolateral prefrontal cortex. Stress amplifies sex differences in gene expression profiles for prefrontal cortical regions involved in stress coping and emotion regulation. Results suggest molecular targets for new treatments of stress disorders in human mental health.

Behavioural Responses of Yunnan Snub-Nosed Monkeys (Rhinopithecus bieti) to Tourists in a Provisioned Monkey Group in Baimaxueshan Nature Reserve.

PubMed

Xia, Wancai; Ren, Baoping; Li, Yanhong; Hu, Jie; He, Xinming; Krzton, Ali; Li, Ming; Li, Dayong

2016-01-01

The appearance of tourists brings about behavioural changes in some primates. Primate behavioural responses to human activities can reflect their survival strategy. Little is known about how the behaviour of Rhinopithecus bieti changes in the presence of tourists. Here we provide the first detailed description of interactions between a provisioned group of R. bieti and tourists at Xiangguqing in Baimaxueshan Nature Reserve from July 2012 to June 2013. We found that R. bieti had different response rates to the 5 most common human actions (shout, photograph, offer food, clap, and wave). Results indicated that R. bieti expresses 10 behavioural reactions (threat, escape, vigilance, warning, panic, alliance, attack, foraging, approach, and staring) to tourists' actions. On the whole, most of the monkeys' responses were unfriendly or hostile; a small number were neutral and affiliative. Behavioural responses were also significantly different among the different age/sex classes. Immature individuals engaged in more affiliative behaviours than adult individuals, and adult males tended towards more hostile behaviours. The behaviour of R. bieti towards tourists showed both tension and adaptability. Scientific management of provisioned monkey groups and strict regulation of tourist behaviour is needed in order to protect the animals from the negative effects of tourism-related disturbance. © 2017 S. Karger AG, Basel.

FoxP2 is a Parvocellular-Specific Transcription Factor in the Visual Thalamus of Monkeys and Ferrets

PubMed Central

Iwai, Lena; Ohashi, Yohei; van der List, Deborah; Usrey, William Martin; Miyashita, Yasushi; Kawasaki, Hiroshi

2013-01-01

Although the parallel visual pathways are a fundamental basis of visual processing, our knowledge of their molecular properties is still limited. Here, we uncovered a parvocellular-specific molecule in the dorsal lateral geniculate nucleus (dLGN) of higher mammals. We found that FoxP2 transcription factor was specifically expressed in X cells of the adult ferret dLGN. Interestingly, FoxP2 was also specifically expressed in parvocellular layers 3–6 of the dLGN of adult old world monkeys, providing new evidence for a homology between X cells in the ferret dLGN and parvocellular cells in the monkey dLGN. Furthermore, this expression pattern was established as early as gestation day 140 in the embryonic monkey dLGN, suggesting that parvocellular specification has already occurred when the cytoarchitectonic dLGN layers are formed. Our results should help in gaining a fundamental understanding of the development, evolution, and function of the parallel visual pathways, which are especially prominent in higher mammals. PMID:22791804

Metagenomic analysis reveals a functional signature for biomass degradation by cecal microbiota in the leaf-eating flying squirrel (Petaurista alborufus lena)

PubMed Central

2012-01-01

Background Animals co-evolve with their gut microbiota; the latter can perform complex metabolic reactions that cannot be done independently by the host. Although the importance of gut microbiota has been well demonstrated, there is a paucity of research regarding its role in foliage-foraging mammals with a specialized digestive system. Results In this study, a 16S rRNA gene survey and metagenomic sequencing were used to characterize genetic diversity and functional capability of cecal microbiota of the folivorous flying squirrel (Petaurista alborufus lena). Phylogenetic compositions of the cecal microbiota derived from 3 flying squirrels were dominated by Firmicutes. Based on end-sequences of fosmid clones from 1 flying squirrel, we inferred that microbial metabolism greatly contributed to intestinal functions, including degradation of carbohydrates, metabolism of proteins, and synthesis of vitamins. Moreover, 33 polysaccharide-degrading enzymes and 2 large genomic fragments containing a series of carbohydrate-associated genes were identified. Conclusions Cecal microbiota of the leaf-eating flying squirrel have great metabolic potential for converting diverse plant materials into absorbable nutrients. The present study should serve as the basis for future investigations, using metagenomic approaches to elucidate the intricate mechanisms and interactions between host and gut microbiota of the flying squirrel digestive system, as well as other mammals with similar adaptations. PMID:22963241

Metagenomic analysis reveals a functional signature for biomass degradation by cecal microbiota in the leaf-eating flying squirrel (Petaurista alborufus lena).

PubMed

Lu, Hsiao-Pei; Wang, Yu-bin; Huang, Shiao-Wei; Lin, Chung-Yen; Wu, Martin; Hsieh, Chih-hao; Yu, Hon-Tsen

2012-09-10

Animals co-evolve with their gut microbiota; the latter can perform complex metabolic reactions that cannot be done independently by the host. Although the importance of gut microbiota has been well demonstrated, there is a paucity of research regarding its role in foliage-foraging mammals with a specialized digestive system. In this study, a 16S rRNA gene survey and metagenomic sequencing were used to characterize genetic diversity and functional capability of cecal microbiota of the folivorous flying squirrel (Petaurista alborufus lena). Phylogenetic compositions of the cecal microbiota derived from 3 flying squirrels were dominated by Firmicutes. Based on end-sequences of fosmid clones from 1 flying squirrel, we inferred that microbial metabolism greatly contributed to intestinal functions, including degradation of carbohydrates, metabolism of proteins, and synthesis of vitamins. Moreover, 33 polysaccharide-degrading enzymes and 2 large genomic fragments containing a series of carbohydrate-associated genes were identified. Cecal microbiota of the leaf-eating flying squirrel have great metabolic potential for converting diverse plant materials into absorbable nutrients. The present study should serve as the basis for future investigations, using metagenomic approaches to elucidate the intricate mechanisms and interactions between host and gut microbiota of the flying squirrel digestive system, as well as other mammals with similar adaptations.

Direct effects of fire on endangered Mount Graham red squirrels

Treesearch

John L. Koprowski; Katherine M. Leonard; Claire A. Zugmeyer; Julia L. Jolley

2006-01-01

Direct mortality of forest wildlife due to fire is rarely documented. In June and July 2004, the Nuttall Complex Fire burned 11,898 ha in the Pinaleno Mountains, southeastern Arizona. Portions of these mountains serve as the only habitat of endangered Mount Graham red squirrels (Tamiasciurus hudsonicus grahamensis). Survival of radio-collared red...

Videos of conspecifics elicit interactive looking patterns and facial expressions in monkeys

PubMed Central

Mosher, Clayton P.; Zimmerman, Prisca E.; Gothard, Katalin M.

2014-01-01

A broader understanding of the neural basis of social behavior in primates requires the use of species-specific stimuli that elicit spontaneous, but reproducible and tractable behaviors. In this context of natural behaviors, individual variation can further inform about the factors that influence social interactions. To approximate natural social interactions similar to those documented by field studies, we used unedited video footage to induce in viewer monkeys spontaneous facial expressions and looking patterns in the laboratory setting. Three adult male monkeys, previously behaviorally and genetically (5-HTTLPR) characterized (Gibboni et al., 2009), were monitored while they watched 10 s video segments depicting unfamiliar monkeys (movie monkeys) displaying affiliative, neutral, and aggressive behaviors. The gaze and head orientation of the movie monkeys alternated between ‘averted’ and ‘directed’ at the viewer. The viewers were not reinforced for watching the movies, thus their looking patterns indicated their interest and social engagement with the stimuli. The behavior of the movie monkey accounted for differences in the looking patterns and facial expressions displayed by the viewers. We also found multiple significant differences in the behavior of the viewers that correlated with their interest in these stimuli. These socially relevant dynamic stimuli elicited spontaneous social behaviors, such as eye-contact induced reciprocation of facial expression, gaze aversion, and gaze following, that were previously not observed in response to static images. This approach opens a unique opportunity to understanding the mechanisms that trigger spontaneous social behaviors in humans and non-human primates. PMID:21688888

Videos of conspecifics elicit interactive looking patterns and facial expressions in monkeys.

PubMed

Mosher, Clayton P; Zimmerman, Prisca E; Gothard, Katalin M

2011-08-01

A broader understanding of the neural basis of social behavior in primates requires the use of species-specific stimuli that elicit spontaneous, but reproducible and tractable behaviors. In this context of natural behaviors, individual variation can further inform about the factors that influence social interactions. To approximate natural social interactions similar to those documented by field studies, we used unedited video footage to induce in viewer monkeys spontaneous facial expressions and looking patterns in the laboratory setting. Three adult male monkeys (Macaca mulatta), previously behaviorally and genetically (5-HTTLPR) characterized, were monitored while they watched 10 s video segments depicting unfamiliar monkeys (movie monkeys) displaying affiliative, neutral, and aggressive behaviors. The gaze and head orientation of the movie monkeys alternated between "averted" and "directed" at the viewer. The viewers were not reinforced for watching the movies, thus their looking patterns indicated their interest and social engagement with the stimuli. The behavior of the movie monkey accounted for differences in the looking patterns and facial expressions displayed by the viewers. We also found multiple significant differences in the behavior of the viewers that correlated with their interest in these stimuli. These socially relevant dynamic stimuli elicited spontaneous social behaviors, such as eye-contact induced reciprocation of facial expression, gaze aversion, and gaze following, that were previously not observed in response to static images. This approach opens a unique opportunity to understanding the mechanisms that trigger spontaneous social behaviors in humans and nonhuman primates. (PsycINFO Database Record (c) 2011 APA, all rights reserved).

Effects of Aroclor 1254 reg sign on hydrocortisone levels in adult Rhesus monkeys (Macaca mulatta)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loo, J.C.K.; Tryphonas, H.; Jordan, N.

Researchers, using female Sprague Dawley rats, reported the effects of chronic (5-7 months) oral dosing with Aroclor 1254{reg sign} (Polychlorinated biphenyls-PCB) on the serum levels of corticosterone, the principle glucocorticoid in rats. Their findings indicated that corticosterone levels were significantly depressed at dose levels of 479 {mu}g/kg bw/day and above. The objective of the present study was to determine the effects of PCB on the hydrocortisone levels in Rhesus monkey (Macaca mulatta) serum. In the monkey the controlling hormone is hydrocortisone which is identical to that of humans.

Transient blindness due to the combined effects of mevinphos and atropine.

DOT National Transportation Integrated Search

1973-02-01

Three squirrel monkeys did not respond to visual stimuli for at least one hour following combined administration of mevinphos (Phosdrin) and atropine. Therefore, aerial applicator personnel being treated for mevinphos (Phosdrin) poisoning with atropi...

Standardized Full-Field Electroretinography in the Green Monkey (Chlorocebus sabaeus)

PubMed Central

Bouskila, Joseph; Javadi, Pasha; Palmour, Roberta M.; Bouchard, Jean-François; Ptito, Maurice

2014-01-01

Abstract Full-field electroretinography is an objective measure of retinal function, serving as an important diagnostic clinical tool in ophthalmology for evaluating the integrity of the retina. Given the similarity between the anatomy and physiology of the human and Green Monkey eyes, this species has increasingly become a favorable non-human primate model for assessing ocular defects in humans. To test this model, we obtained full-field electroretinographic recordings (ERG) and normal values for standard responses required by the International Society for Clinical Electrophysiology of Vision (ISCEV). Photopic and scotopic ERG recordings were obtained by full-field stimulation over a range of 6 log units of intensity in dark-adapted or light-adapted eyes of adult Green Monkeys (Chlorocebus sabaeus). Intensity, duration, and interval of light stimuli were varied separately. Reproducible values of amplitude and latency were obtained for the a- and b-waves, under well-controlled adaptation and stimulus conditions; the i-wave was also easily identifiable and separated from the a-b-wave complex in the photopic ERG. The recordings obtained in the healthy Green Monkey matched very well with those in humans and other non-human primate species (Macaca mulatta and Macaca fascicularis). These results validate the Green Monkey as an excellent non-human primate model, with potential to serve for testing retinal function following various manipulations such as visual deprivation or drug evaluation. PMID:25360686

Risky business: rhesus monkeys exhibit persistent preferences for risky options.

PubMed

Xu, Eric R; Kralik, Jerald D

2014-01-01

Rhesus monkeys have been shown to prefer risky over safe options in experiential decision-making tasks. These findings might be due, however, to specific contextual factors, such as small amounts of fluid reward and minimal costs for risk-taking. To better understand the factors affecting decision-making under risk in rhesus monkeys, we tested multiple factors designed to increase the stakes including larger reward amounts, distinct food items rather than fluid reward, a smaller number of trials per session, and risky options with greater variation that also included non-rewarded outcomes. We found a consistent preference for risky options, except when the expected value of the safe option was greater than the risky option. Thus, with equivalent mean utilities between the safe and risky options, rhesus monkeys appear to have a robust preference for the risky options in a broad range of circumstances, akin to the preferences found in human children and some adults in similar tasks. One account for this result is that monkeys make their choices based on the salience of the largest payoff, without integrating likelihood and value across trials. A related idea is that they fail to override an impulsive tendency to select the option with the potential to obtain the highest possible outcome. Our results rule out strict versions of both accounts and contribute to an understanding of the diversity of risky decision-making among primates.

Partial recovery of hemiparesis following hemispherectomy in infant monkeys.

PubMed

Burke, Mark W; Zangenehpour, Shahin; Ptito, Maurice

2010-01-22

Hemiparesis, unilateral weakness or partial paralysis, is a common outcome following hemispherectomy in humans. We use the non-human primate as an invaluable translational model for our understanding of developmental plasticity in response to hemispherectomy. Three infant vervet monkeys (Chlorocebus sabeus) underwent hemispherectomy at a median age of 9 weeks and two additional monkeys at 48 months. Gross motor assessment was conducted in a large open field that contained a horizontal bar spanning the width of the cage. Subjects were assessed yearly following surgery in infantile lesions for a period of 3 years. Adult-lesioned subjects were assessed 40 months following surgery. Shortly after surgery both infant and adult-lesioned subjects were unable to move the contralateral side of their body, but all subjects were able to walk within 6 months following surgery. At each time point the lower limb gait was normal in infant-lesioned subjects with no apparent limp or dragging, however the upper limb demonstrated significant impairment. Horizontal bar crossing was significantly impaired during the first 24 months following surgery. Adult-lesioned subjects also displayed upper limb movement impairments similar to infant-lesioned subjects. In addition the adult-lesioned subjects displayed a noticeable lower limb limp, which was not observed in the infant-lesioned group. Both groups at each time point showed a propensity for ipsiversive turning. The upper limb gait impairment and horizontal bar crossing of lesioned subjects are reminiscent of hemiparesis seen in hemisperectomized humans with the young-lesioned subjects showing a greater propensity for recovery. (c) 2009 Elsevier Ireland Ltd. All rights reserved.

Social conditioned place preference in the captive ground squirrel Ictidomys tridecemlineatus: Social reward as a natural phenotype

PubMed Central

Lahvis, Garet P.; Panksepp, Jules B.; Kennedy, Bruce C.; Wilson, Clarinda R.; Merriman, Dana K.

2015-01-01

Social behaviors of wild animals are often considered within an ultimate framework of adaptive benefits versus survival risks. By contrast, studies of laboratory animals more typically focus on affective aspects of behavioral decisions, whether a rodent derives a rewarding experience from social encounter and how this experience might be initiated and maintained by neural circuits. Artificial selection and inbreeding have rendered laboratory animals more affiliative and less aggressive than their wild conspecifics, leaving open the possibility that social reward is an artifact of domestication. We compared social behaviors of wild and captive population of juvenile 13-lined ground squirrels (Ictidomys tridecemlineatus), the latter 2nd and 3rd generation descendents of wild individuals. At an age corresponding to emergence from the burrow, postnatal day 38, captive squirrels engaged in vigorous social approach and play; these juvenile behaviors declined significantly by postnatal day 56. Similarly, young wild squirrels expressed social proximity and play, affiliative interactions declined with summer’s progression and were replaced by agonistic chasing behaviors. Social conditioned place preference testing (conditioned postnatal days 40–50) indicated that adolescent squirrels derived a rewarding experience from social reunion. Our results support the contention that undomesticated rodents have the capacity for social reward and more generally suggest the possibility that positive affective experiences may support group cohesion and social cooperation in the wild. PMID:26147706

Attentional biases and memory for emotional stimuli in men and male rhesus monkeys.

PubMed

Lacreuse, Agnès; Schatz, Kelly; Strazzullo, Sarah; King, Hanna M; Ready, Rebecca

2013-11-01

We examined attentional biases for social and non-social emotional stimuli in young adult men and compared the results to those of male rhesus monkeys (Macaca mulatta) previously tested in a similar dot-probe task (King et al. in Psychoneuroendocrinology 37(3):396-409, 2012). Recognition memory for these stimuli was also analyzed in each species, using a recognition memory task in humans and a delayed non-matching-to-sample task in monkeys. We found that both humans and monkeys displayed a similar pattern of attentional biases toward threatening facial expressions of conspecifics. The bias was significant in monkeys and of marginal significance in humans. In addition, humans, but not monkeys, exhibited an attentional bias away from negative non-social images. Attentional biases for social and non-social threat differed significantly, with both species showing a pattern of vigilance toward negative social images and avoidance of negative non-social images. Positive stimuli did not elicit significant attentional biases for either species. In humans, emotional content facilitated the recognition of non-social images, but no effect of emotion was found for the recognition of social images. Recognition accuracy was not affected by emotion in monkeys, but response times were faster for negative relative to positive images. Altogether, these results suggest shared mechanisms of social attention in humans and monkeys, with both species showing a pattern of selective attention toward threatening faces of conspecifics. These data are consistent with the view that selective vigilance to social threat is the result of evolutionary constraints. Yet, selective attention to threat was weaker in humans than in monkeys, suggesting that regulatory mechanisms enable non-anxious humans to reduce sensitivity to social threat in this paradigm, likely through enhanced prefrontal control and reduced amygdala activation. In addition, the findings emphasize important differences in

Potential for nest site competition between native and exotic tree squirrels

Treesearch

Andrew J. Edelman; John L. Koprowski; Sadie R. Bertelsen

2009-01-01

In communities where strong interspecific competition between native species is lacking, exotic and native species often exhibit intense resource competition resulting in decline of native populations. We examined the potential for interspecific competition for nest sites between co-occurring native Mt. Graham red squirrels (Tamiasciurus hudsonicus grahamensis...

Do monkeys choose to choose?

PubMed

Perdue, Bonnie M; Evans, Theodore A; Washburn, David A; Rumbaugh, Duane M; Beran, Michael J

2014-06-01

Both empirical and anecdotal evidence supports the idea that choice is preferred by humans. Previous research has demonstrated that this preference extends to nonhuman animals, but it remains largely unknown whether animals will actively seek out or prefer opportunities to choose. Here we explored the issue of whether capuchin and rhesus monkeys choose to choose. We used a modified version of the SELECT task-a computer program in which monkeys can choose the order of completion of various psychomotor and cognitive tasks. In the present experiments, each trial began with a choice between two icons, one of which allowed the monkey to select the order of task completion, and the other of which led to the assignment of a task order by the computer. In either case, subjects still had to complete the same number of tasks and the same number of task trials. The tasks were relatively easy, and the monkeys responded correctly on most trials. Thus, global reinforcement rates were approximately equated across conditions. The only difference was whether the monkey chose the task order or it was assigned, thus isolating the act of choosing. Given sufficient experience with the task icons, all monkeys showed a significant preference for choice when the alternative was a randomly assigned order of tasks. To a lesser extent, some of the monkeys maintained a preference for choice over a preferred, but computer-assigned, task order that was yoked to their own previous choice selection. The results indicated that monkeys prefer to choose when all other aspects of the task are equated.

Comparative anatomy of the arm muscles of the Japanese monkey (Macaca fuscata) with some comments on locomotor mechanics and behavior.

PubMed

Aversi-Ferreira, Tales Alexandre; Aversi-Ferreira, Roqueline A G M F; Bretas, Rafael Vieira; Nishimaru, Hiroshi; Nishijo, Hisao

2016-08-01

The anatomical literature on the genus Macaca has focused mainly on the rhesus monkey. However, some aspects in the positional behaviors of the Japanese monkey may be different from those in rhesus monkey, suggesting that the anatomical details of these species are divergent. Four thoracic limbs of Macaca fuscata adults were dissected. The arm muscles in Japanese macaques are more similar to rhesus monkeys and Papio; these characteristics are closer to those of bearded capuchins than apes, indicating more proximity of this genus to New World primates. The anatomical features observed favor quadrupedal locomotor behaviors on the ground and in arboreal environments. Japanese monkeys, rhesus monkeys, and bearded capuchins, which share more primitive characteristics in their arm muscles, present features that favor both arboreal and quadrupedal locomotor behaviors, whereas apes, mainly Pan and Gorilla, which spend more time on the ground, present more quadrupedal specializations. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of forest management on truffle abundance and squirrel diets.

Treesearch

A.B. Carey; W. Colgan; J.M. Trappe; R. Molina

2002-01-01

Thinning and retention of biological legacies (large live, dead, and fallen trees and their associated biota) during clearcutting are two practices to promote development of late-seral attributes in second-growth forests. We evaluated the effects of these practices on production of truffles and use of truffles as food by northern flying squirrels and Townsend’s...

Sensorless speed detection of squirrel-cage induction machines using stator neutral point voltage harmonics

NASA Astrophysics Data System (ADS)

Petrovic, Goran; Kilic, Tomislav; Terzic, Bozo

2009-04-01

In this paper a sensorless speed detection method of induction squirrel-cage machines is presented. This method is based on frequency determination of the stator neutral point voltage primary slot harmonic, which is dependent on rotor speed. In order to prove method in steady state and dynamic conditions the simulation and experimental study was carried out. For theoretical investigation the mathematical model of squirrel cage induction machines, which takes into consideration actual geometry and windings layout, is used. Speed-related harmonics that arise from rotor slotting are analyzed using digital signal processing and DFT algorithm with Hanning window. The performance of the method is demonstrated over a wide range of load conditions.

Systems Biology of the Vervet Monkey

PubMed Central

Jasinska, Anna J.; Schmitt, Christopher A.; Service, Susan K.; Cantor, Rita M.; Dewar, Ken; Jentsch, James D.; Kaplan, Jay R.; Turner, Trudy R.; Warren, Wesley C.; Weinstock, George M.; Woods, Roger P.; Freimer, Nelson B.

2013-01-01

Nonhuman primates (NHP) provide crucial biomedical model systems intermediate between rodents and humans. The vervet monkey (also called the African green monkey) is a widely used NHP model that has unique value for genetic and genomic investigations of traits relevant to human diseases. This article describes the phylogeny and population history of the vervet monkey and summarizes the use of both captive and wild vervet monkeys in biomedical research. It also discusses the effort of an international collaboration to develop the vervet monkey as the most comprehensively phenotypically and genomically characterized NHP, a process that will enable the scientific community to employ this model for systems biology investigations. PMID:24174437

Glide performance and aerodynamics of non-equilibrium glides in northern flying squirrels (Glaucomys sabrinus)

PubMed Central

Bahlman, Joseph W.; Swartz, Sharon M.; Riskin, Daniel K.; Breuer, Kenneth S.

2013-01-01

Gliding is an efficient form of travel found in every major group of terrestrial vertebrates. Gliding is often modelled in equilibrium, where aerodynamic forces exactly balance body weight resulting in constant velocity. Although the equilibrium model is relevant for long-distance gliding, such as soaring by birds, it may not be realistic for shorter distances between trees. To understand the aerodynamics of inter-tree gliding, we used direct observation and mathematical modelling. We used videography (60–125 fps) to track and reconstruct the three-dimensional trajectories of northern flying squirrels (Glaucomys sabrinus) in nature. From their trajectories, we calculated velocities, aerodynamic forces and force coefficients. We determined that flying squirrels do not glide at equilibrium, and instead demonstrate continuously changing velocities, forces and force coefficients, and generate more lift than needed to balance body weight. We compared observed glide performance with mathematical simulations that use constant force coefficients, a characteristic of equilibrium glides. Simulations with varying force coefficients, such as those of live squirrels, demonstrated better whole-glide performance compared with the theoretical equilibrium state. Using results from both the observed glides and the simulation, we describe the mechanics and execution of inter-tree glides, and then discuss how gliding behaviour may relate to the evolution of flapping flight. PMID:23256188

Glide performance and aerodynamics of non-equilibrium glides in northern flying squirrels (Glaucomys sabrinus).

PubMed

Bahlman, Joseph W; Swartz, Sharon M; Riskin, Daniel K; Breuer, Kenneth S

2013-03-06

Gliding is an efficient form of travel found in every major group of terrestrial vertebrates. Gliding is often modelled in equilibrium, where aerodynamic forces exactly balance body weight resulting in constant velocity. Although the equilibrium model is relevant for long-distance gliding, such as soaring by birds, it may not be realistic for shorter distances between trees. To understand the aerodynamics of inter-tree gliding, we used direct observation and mathematical modelling. We used videography (60-125 fps) to track and reconstruct the three-dimensional trajectories of northern flying squirrels (Glaucomys sabrinus) in nature. From their trajectories, we calculated velocities, aerodynamic forces and force coefficients. We determined that flying squirrels do not glide at equilibrium, and instead demonstrate continuously changing velocities, forces and force coefficients, and generate more lift than needed to balance body weight. We compared observed glide performance with mathematical simulations that use constant force coefficients, a characteristic of equilibrium glides. Simulations with varying force coefficients, such as those of live squirrels, demonstrated better whole-glide performance compared with the theoretical equilibrium state. Using results from both the observed glides and the simulation, we describe the mechanics and execution of inter-tree glides, and then discuss how gliding behaviour may relate to the evolution of flapping flight.

Do rhesus monkeys (Macaca mulatta) perceive illusory motion?

PubMed

Agrillo, Christian; Gori, Simone; Beran, Michael J

2015-07-01

During the last decade, visual illusions have been used repeatedly to understand similarities and differences in visual perception of human and non-human animals. However, nearly all studies have focused only on illusions not related to motion perception, and to date, it is unknown whether non-human primates perceive any kind of motion illusion. In the present study, we investigated whether rhesus monkeys (Macaca mulatta) perceived one of the most popular motion illusions in humans, the Rotating Snake illusion (RSI). To this purpose, we set up four experiments. In Experiment 1, subjects initially were trained to discriminate static versus dynamic arrays. Once reaching the learning criterion, they underwent probe trials in which we presented the RSI and a control stimulus identical in overall configuration with the exception that the order of the luminance sequence was changed in a way that no apparent motion is perceived by humans. The overall performance of monkeys indicated that they spontaneously classified RSI as a dynamic array. Subsequently, we tested adult humans in the same task with the aim of directly comparing the performance of human and non-human primates (Experiment 2). In Experiment 3, we found that monkeys can be successfully trained to discriminate between the RSI and a control stimulus. Experiment 4 showed that a simple change in luminance sequence in the two arrays could not explain the performance reported in Experiment 3. These results suggest that some rhesus monkeys display a human-like perception of this motion illusion, raising the possibility that the neurocognitive systems underlying motion perception may be similar between human and non-human primates.

Excavation of red squirrel middens by grizzly bears in the whitebark pine zone

USGS Publications Warehouse

Mattson, D.J.; Reinhart, Daniel P.

1997-01-01

Whitebark pine seeds Pinus albicaulis are an important food of grizzly Ursus arctos horribilis bears wherever whitebark pine is abundant in the contiguous United States of America; availability of seeds affects the distribution of bears, and the level of conflict between bears and humans. Almost all of the seeds consumed by bears are excavated from middens where red squirrels Tamiasciurus hudsonicus have cached whitebark pine cones.Relationships among the occupancy of middens by squirrels, the excavation of middens by bears, and site features were investigated in this study. Data were collected from radio-marked bears and from middens located from line transects on two study sites in the Yellowstone ecosystem.Densities of active middens were positively related to lodgepole pine Pinus contorta basal area and negatively related to steepness of slope.The probability that a midden was occupied by a squirrel (i.e. active) was positively related to lodgepole pine basal area in the surrounding stand, size of the midden and size of the whitebark pine cone crop, and negatively related to elevation and to bear excavation during the previous 2-12 months.The probability that a midden had been excavated by a bear during the previous 12 months was positively related to size of the midden, and to whitebark pine basal area and cone crop, and negatively related to nearness of roads and town sites.The influence of midden size on bear use was attributable to a positive relationship with the number of excavated cones. The positive association between bear excavations and whitebark pine basal area or cone crops was attributable to availability of pine seeds.Grizzly bears would benefit from the minimization of roads and other human facilities in the whitebark pine zone and from increases in the availability of whitebark pine seeds, potentially achieved by increasing the numbers of cone-producing whitebark pine trees, especially in lower elevations of the whitebark pine zone where red

Precise Motor Control Enables Rapid Flexibility in Vocal Behavior of Marmoset Monkeys.

PubMed

Pomberger, Thomas; Risueno-Segovia, Cristina; Löschner, Julia; Hage, Steffen R

2018-03-05

Investigating the evolution of human speech is difficult and controversial because human speech surpasses nonhuman primate vocal communication in scope and flexibility [1-3]. Monkey vocalizations have been assumed to be largely innate, highly affective, and stereotyped for over 50 years [4, 5]. Recently, this perception has dramatically changed. Current studies have revealed distinct learning mechanisms during vocal development [6-8] and vocal flexibility, allowing monkeys to cognitively control when [9, 10], where [11], and what to vocalize [10, 12, 13]. However, specific call features (e.g., duration, frequency) remain surprisingly robust and stable in adult monkeys, resulting in rather stereotyped and discrete call patterns [14]. Additionally, monkeys seem to be unable to modulate their acoustic call structure under reinforced conditions beyond natural constraints [15, 16]. Behavioral experiments have shown that monkeys can stop sequences of calls immediately after acoustic perturbation but cannot interrupt ongoing vocalizations, suggesting that calls consist of single impartible pulses [17, 18]. Using acoustic perturbation triggered by the vocal behavior itself and quantitative measures of resulting vocal adjustments, we show that marmoset monkeys are capable of producing calls with durations beyond the natural boundaries of their repertoire by interrupting ongoing vocalizations rapidly after perturbation onset. Our results indicate that marmosets are capable of interrupting vocalizations only at periodic time points throughout calls, further supported by the occurrence of periodically segmented phees. These ideas overturn decades-old concepts on primate vocal pattern generation, indicating that vocalizations do not consist of one discrete call pattern but are built of many sequentially uttered units, like human speech. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

The influence of changing seasonality and snow cover on arctic ground squirrel phenology.

NASA Astrophysics Data System (ADS)

Barnes, B.; Sheriff, M.; Kenagy, J.; Buck, L.; Team Squirrel

2011-12-01

A warming climate in the Arctic may have asymmetrical effects on seasonality, depending on the timing and extent of snow cover. Warm autumns that delay the onset of persistent snow cover will lengthen growing seasons of some plants and, combined with continuing access to fallen seeds, berries, and leaves, extend feeding opportunities for ground foragers. Warming in spring should advance when the ground becomes snow free and the onset of plant productivity, leading overall to a longer growing season. However, if winter and spring precipitation increase, as is predicted in climate models, the amount and seasonal extent of snow pack will increase, which will delay melt and lead to delayed springs. Either of these scenarios may develop regionally, depending on local weather, snow, and wind. Since 1996, we have been investigating the timing of annual events in natural populations of arctic ground squirrels, Urocitellus parryii, living at two nearby sites (Toolik and Atigun, 68o38'N) in arctic Alaska that greatly differ in timing and duration of snow cover. Since arctic ground squirrels are highly dependent on snow free ground for foraging, we predicted that these environmental differences will have had major impacts on life histories and timing of annual events on the local populations. Precision in dates of the beginning and end of hibernation, use of heterothermy, and birth of young were determined by temperature-sensitive data loggers implanted into juvenile and adult animals of both sexes. Weather stations, snow cameras, and transects for plant phenology are in place at both locations, although record lengths differ. While across the past 15 years annual timing of hibernation and breeding has not shown significant trends at either site, the two populations have differed consistently in hibernation timing and length of active season, and they show a 13 day difference in average timing of reproduction. These results reveal a substantial flexibility of timing of the

Effects of near-UV radiation on the protein of the grey squirrel lens.

PubMed

Zigman, S; Paxhia, T; Waldron, W

1988-06-01

In vivo exposure of grey squirrels to 40W BLB illumination resulted in alterations in the state of the lens crystallins, mainly in the outer layer of the lens. HPLC revealed an increase of the void volume or crosslinked crystallins and an increase in peptides with molecular weights lower than 20,000 d. In vitro exposure of squirrel lens aqueous extracts to Woods lamp radiation (predominantly 365 nm) led to similar but more exaggerated changes as viewed by high performance liquid chromatography. When viewed by polyacrylamide gel electrophoresis (PAGE), soluble protein crosslinking was also observed. The near-UV absorbing chromophores of low molecular weight present in the lens served as photosensitizers that enhanced the protein changes. Sodium azide inhibited the changes, indicating a role for singlet oxygen in the crosslinking.

Effects of prior cocaine self-administration on cognitive performance in female cynomolgus monkeys.

PubMed

Kromrey, Sarah A; Gould, Robert W; Nader, Michael A; Czoty, Paul W

2015-06-01

Cocaine use has been associated with cognitive impairments that may contribute to poor treatment outcomes. However, the degree to which these deficits extend into periods of abstinence has not been completely elucidated. This study tested whether prior experience self-administering cocaine affected acquisition of two cognitive tasks in 16 adult female cynomolgus monkeys. Seven monkeys had previously self-administered cocaine but had not had access to cocaine for 2 months at the start of this study. After monkeys were trained to respond on a touchscreen, associative learning and behavioral flexibility were assessed using a stimulus discrimination (SD) and reversal (SDR) task from the CANTAB battery. Performance on this task was monitored over the subsequent 3 months. Additionally, working memory was assessed with a delayed match-to-sample (DMS) task. Cocaine-naïve monkeys required fewer total trials and made fewer errors and omissions before acquiring the SD and SDR tasks compared with monkeys who had previously self-administered cocaine; two monkeys in the latter group did not acquire the task. However, this cognitive impairment dissipated over several months of exposure to the task. The number of sessions for touch training and delays required to establish a performance-based curve on the DMS task did not differ between groups. Results suggest that cocaine exposure can impair the ability to learn a novel task requiring behavioral inhibition and flexibility, even after an extended period of abstinence. However, this deficit did not extend to maintenance of the task or to acquisition of a working memory task.

Experimental manipulation of spatial heterogeneity in Douglas-fir forests: effects on squirrels.

Treesearch

A.B. Carey

2001-01-01

Squirrel communities simultaneously composed of abundant populations of Glaucomys, Tamias, and Tamiasciurus are: (1) a result of high production of seeds and fruiting bodies by forest plants and fungi and complexity of ecosystem structure, composition, and function; (2) indicative of high carrying capacity...

Acorn Caching in Tree Squirrels: Teaching Hypothesis Testing in the Park

ERIC Educational Resources Information Center

McEuen, Amy B.; Steele, Michael A.

2012-01-01

We developed an exercise for a university-level ecology class that teaches hypothesis testing by examining acorn preferences and caching behavior of tree squirrels (Sciurus spp.). This exercise is easily modified to teach concepts of behavioral ecology for earlier grades, particularly high school, and provides students with a theoretical basis for…

Den use and selection by northern flying squirrels in fragmented landscapes

Treesearch

Sanjay Pyare; Winston P. Smith; Colin S. Shanley

2010-01-01

We studied den use and den-habitat selection by the Prince of Wales Island flying squirrel (Glaucomys sabrinus griseifrons) at multiple spatial scales in fragmented temperate rain-forest habitats because of the role dens play in the distribution, reproduction, and population density of this endemic subspecies. We observed differences in spatial...

Antigenic Relationships Among Four Herpesviruses

PubMed Central

Blue, W. T.; Plummer, G.

1973-01-01

Common viral antigens were detected, by fluorescent-antibody studies, in cells infected with herpes simplex virus 1, squirrel monkey herpesvirus 1, bovine rhinotracheitis, and equine abortion viruses. The two primate viruses showed slight cross-neutralization. PMID:4351969

A metacognitive illusion in monkeys.

PubMed

Ferrigno, Stephen; Kornell, Nate; Cantlon, Jessica F

2017-09-13

Like humans, monkeys can make accurate judgements about their own memory by reporting their confidence during cognitive tasks. Some have suggested that animals use associative learning to make accurate confidence judgements, while others have suggested animals directly access and estimate the strength of their memories. Here we test a third, non-exclusive possibility: perhaps monkeys, like humans, base metacognitive inferences on heuristic cues. Humans are known to use cues like perceptual fluency (e.g. how easy something is to see) when making metacognitive judgements. We tested monkeys using a match-to-sample task in which the perceptual fluency of the stimuli was manipulated. The monkeys made confidence wagers on their accuracy before or after each trial. We found that monkeys' wagers were affected by perceptual fluency even when their accuracy was not. This is novel evidence that animals are susceptible to metacognitive illusions similar to those experienced by humans. © 2017 The Author(s).

Signaling Lymphocytic Activation Molecule Family Receptor Homologs in New World Monkey Cytomegaloviruses.

PubMed

Pérez-Carmona, Natàlia; Farré, Domènec; Martínez-Vicente, Pablo; Terhorst, Cox; Engel, Pablo; Angulo, Ana

2015-11-01

Throughout evolution, large DNA viruses have been usurping genes from their hosts to equip themselves with proteins that restrain host immune defenses. Signaling lymphocytic activation molecule (SLAM) family (SLAMF) receptors are involved in the regulation of both innate and adaptive immunity, which occurs upon engagement with their ligands via homotypic or heterotypic interactions. Here we report a total of seven SLAMF genes encoded by the genomes of two cytomegalovirus (CMV) species, squirrel monkey CMV (SMCMV) and owl monkey CMV (OMCMV), that infect New World monkeys. Our results indicate that host genes were captured by retrotranscription at different stages of the CMV-host coevolution. The most recent acquisition led to S1 in SMCMV. S1 is a SLAMF6 homolog with an amino acid sequence identity of 97% to SLAMF6 in its ligand-binding N-terminal Ig domain. We demonstrate that S1 is a cell surface glycoprotein capable of binding to host SLAMF6. Furthermore, the OMCMV genome encodes A33, an LY9 (SLAMF3) homolog, and A43, a CD48 (SLAMF2) homolog, two soluble glycoproteins which recognize their respective cellular counterreceptors and thus are likely to be viral SLAMF decoy receptors. In addition, distinct copies of further divergent CD48 homologs were found to be encoded by both CMV genomes. Remarkably, all these molecules display a number of unique features, including cytoplasmic tails lacking characteristic SLAMF signaling motifs. Taken together, our findings indicate a novel immune evasion mechanism in which incorporation of host SLAMF receptors that retain their ligand-binding properties enables viruses to interfere with SLAMF functions and to supply themselves with convenient structural molds for expanding their immunomodulatory repertoires. The way in which viruses shape their genomes under the continual selective pressure exerted by the host immune system is central for their survival. Here, we report that New World monkey cytomegaloviruses have broadly

Spaceflight and immune responses of rhesus monkeys

NASA Technical Reports Server (NTRS)

Sonnenfeld, Gerald; Morton, Darla S.; Swiggett, Jeanene P.; Hakenewerth, Anne M.; Fowler, Nina A.

1995-01-01

The effects of restraint on immunological parameters was determined in an 18 day ARRT (adult rhesus restraint test). The monkeys were restrained for 18 days in the experimental station for the orbiting primate (ESOP), the chair of choice for Space Shuttle experiments. Several immunological parameters were determined using peripheral blood, bone marrow, and lymph node specimens from the monkeys. The parameters included: response of bone marrow cells to GM-CSF (granulocyte-macrophage colony stimulating factor), leukocyte subset distribution, and production of IFN-a (interferon-alpha) and IFN-gamma (interferon-gamma). The only parameter changed after 18 days of restraint was the percentage of CD8+ T cells. No other immunological parameters showed changes due to restraint. Handling and changes in housing prior to the restraint period did apparently result in some restraint-independent immunological changes. Handling must be kept to a minimum and the animals allowed time to recover prior to flight. All experiments must be carefully controlled. Restraint does not appear to be a major issue regarding the effects of space flight on immune responses.

Evolutionary Transformation of the Palmaris Longus Muscle in Flying Squirrels (Pteromyini: Sciuridae): An Anatomical Consideration of the Origin of the Uniquely Specialized Styliform Cartilage.

PubMed

Kawashima, Tomokazu; Thorington, Richard W; Bohaska, Paula W; Sato, Fumi

2017-02-01

A long-standing issue in squirrel evolution and development is the origin of the styliform cartilage of flying squirrels, which extends laterally from the carpus to support the gliding membrane (patagium). Because the styliform cartilage is one of the uniquely specialized structures permitting gliding locomotion, the knowledge of its origin and surrounding transformation is key for understanding their aerodynamic evolution. The developmental study that would definitely answer this question would be difficult due to the rarity of embryological material. Instead, anatomical examinations have suggested two major hypotheses on the homology of the styliform cartilage: the pisiform bone of other mammals, or an additional carpal structure, such as the ulnar sesamoid of some of the other mammals or the hypothenar cartilage of the non-gliding squirrels. To test these hypotheses, a detailed examination of the anatomy of the carpus of gliding and non-gliding squirrels, and the colugo were undertaken. Based on physical and virtual dissections of the carpus, this study showed that both the pisiform bone and styliform cartilage were present in flying squirrels. This finding is further supported by demonstration that a "true Palmaris longus," with innervation typical for this muscle, inserts on the styliform cartilage. Taken together, our osteological, muscular, and neurological results suggest that the styliform cartilage was transformed in flying squirrels from an initially superficial and ulnar-derived anlagen into its current form. Anat Rec, 300:340-352, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Purification and characterization of fructose bisphosphate aldolase from the ground squirrel, Spermophilus lateralis: enzyme role in mammalian hibernation.

PubMed

MacDonald, Justin A; Storey, Kenneth B

2002-12-15

Fructose-1,6-bisphosphate (F1,6P(2)) aldolase was purified to homogeneity from skeletal muscle of the golden-mantled ground squirrel, Spermophilus lateralis. Enzyme properties were examined at temperatures characteristic of euthermia (37 degrees C) and hibernation (5 degrees C); parallel studies assessed rabbit muscle aldolase for comparison. Kinetic properties of each enzyme were differentially affected by assay temperature. For example, the K(m) for F1,6P(2) of ground squirrel aldolase was 0.9+/-0.05 microM at 37 degrees C and 50% higher (1.45+/-0.04 microM) at 5 degrees C, whereas the K(m) of rabbit aldolase increased threefold over the same temperature range. The inhibitory effects of adenylates were similar at both temperatures for the ground squirrel enzyme, but inhibition by adenosine 5(')-diphosphate, adenosine 5(')-monophosphate, and inosine 5(')-monophosphate was substantially reduced at 5 degrees C for rabbit aldolase. Inhibition by inorganic phosphate increased at lower temperatures for both enzymes; for ground squirrel aldolase, the K(i) was 1.18+/-0.1mM at 37 degrees C and 0.23+/-0.05 mM at 5 degrees C. Inhibition of aldolase by inorganic phosphate could be one factor that helps to shut down glycolysis during hibernation. Thus, mammalian hibernators may exploit low-temperature characteristics of aldolase to benefit the metabolic needs of the hibernating state.

Age and seasonal differences in the synthesis and metabolism of testosterone by testicular tissue and pineal HIOMT activity of Uinta ground squirrels (Spermophilus armatus)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellis, L.C.; Balph, D.F.

Male Uinta ground squirrels (Spermophilus armatus) were sacrificed from a free-living population during the breeding season, which immediately followed emergence from hibernation; after the reproductive season; and just prior to aestivation/hibernation. HIOMT activity of the pineal gland was assayed and related to the ability of the gonads to synthesize and metabolize testosterone. Older squirrels had higher HIOMT activity than did the younger animals. The activity of this enzyme was lowest in squirrels during the breeding season. HIOMT activity increased after the breeding season to its highest level just before the squirrels enter aestivation/hibernation. At this time, testicular weight increased concomitantmore » with an apparent increase in HIOMT activity. Testicular size and weight were largest at the time of emergence of the animals from hibernation. Androgen synthesis was also greatest during the breeding season. As would be expected, both decreased rapidly thereafter. The testes formed little 17..cap alpha..,20..cap alpha..-dihydroxyprogesterone during or after the breeding season, contrary to what has been reported for rats and house sparrows. The older squirrels demonstrated a greater capacity for testosterone metabolism during the breeding season than did the younger animals.« less

DNA analysis of a 30,000-year-old Urocitellus glacialis from northeastern Siberia reveals phylogenetic relationships between ancient and present-day arctic ground squirrels

PubMed Central

Faerman, Marina; Bar-Gal, Gila Kahila; Boaretto, Elisabetta; Boeskorov, Gennady G.; Dokuchaev, Nikolai E.; Ermakov, Oleg A.; Golenishchev, Fedor N.; Gubin, Stanislav V.; Mintz, Eugenia; Simonov, Evgeniy; Surin, Vadim L.; Titov, Sergei V.; Zanina, Oksana G.; Formozov, Nikolai A.

2017-01-01

In contrast to the abundant fossil record of arctic ground squirrels, Urocitellus parryii, from eastern Beringia, only a limited number of fossils is known from its western part. In 1946, unnamed GULAG prisoners discovered a nest with three mummified carcasses of arctic ground squirrels in the permafrost sediments of the El’ga river, Yakutia, Russia, that were later attributed to a new species, Citellus (Urocitellus) glacialis Vinogr. To verify this assignment and to explore phylogenetic relationships between ancient and present-day arctic ground squirrels, we performed 14C dating and ancient DNA analyses of one of the El’ga mummies and four contemporaneous fossils from Duvanny Yar, northeastern Yakutia. Phylogenetic reconstructions, based on complete cytochrome b gene sequences of five Late Pleistocene arctic ground squirrels and those of modern U. parryii from 21 locations across western Beringia, provided no support for earlier proposals that ancient arctic ground squirrels from Siberia constitute a distinct species. In fact, we observed genetic continuity of the glacialis mitochondrial DNA lineage in modern U. parryii of the Kamchatka peninsula. When viewed in a broader geographic perspective, our findings provide new insights into the genetic history of U. parryii in Late Pleistocene Beringia. PMID:28205612

Sexual dimorphism of sulcal length asymmetry in the cerebrum of adult cynomolgus monkeys (Macaca fascicularis).

PubMed

Imai, Noritaka; Sawada, Kazuhiko; Fukunishi, Katsuhiro; Sakata-Haga, Hiromi; Fukui, Yoshihiro

2011-12-01

The present study aimed to quantitatively clarify the gross anatomical asymmetry and sexual dimorphism of the cerebral hemispheres of cynomolgus monkeys. While the fronto-occipital length of the right and left cerebral hemispheres was not different between sexes, a statistically significant rightward asymmetry was detected in the cerebral width at the perisylvian region in females, but not in males (narrower width of the left side in the females). An asymmetry quotient of the sulcal lengths revealed a rightward asymmetry in the inferior occipital sulcus and a leftward asymmetry in the central and intraparietal sulci in both sexes. However, the laterality of the lengths of other sulci was different for males and females. The arcuate sulcus was directed rightward in males but there was no rightward bias in females. Interestingly, the principle sulcus and lateral fissure were left-lateralized in the males, but right-lateralized in the females. The results suggest that lateralization patterns are regionally and sexually different in the cerebrum of cynomolgus monkeys. The present results provide a reference for quantitatively evaluating the normality of the cerebral cortical morphology in cynomolgus monkeys. © 2011 The Authors. Congenital Anomalies © 2011 Japanese Teratology Society.

Metabolism and pharmacokinetics of the combination Zidovudine plus Lamivudine in the adult Erythrocebus patas monkey determined by liquid chromatography-tandem mass spectrometric analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Divi, Rao L.; Doerge, Daniel R.; Twaddle, Nathan C.

2008-01-15

Because of their similarity to humans, non-human primates constitute useful preclinical models in which to examine potential human drug toxicities. Antiretroviral nucleoside reverse transcriptase inhibitor (NRTI) toxicity is currently under investigation in Erythrocebus patas monkeys, and whereas NRTI pharmacokinetics have been studied in other monkey species, pharmacokinetics for Zidovudine plus Lamivudine (AZT/3TC) dosing have not been reported in the patas. Here we present 24 h serum pharmacokinetic parameters after a single oral exposure to the combination of AZT (40 mg) and 3TC (24 mg), doses equivalent to a human daily dose of Combivir (registered) . The patas (n = 3)more » AZT/3TC pharmacokinetic profiles were similar to those seen in other primate species. Average maximum serum concentrations (C{sub max}) for AZT and 3TC were 2.35 and 2.65 {mu}g/ml, respectively, and were observed at 0.83 h (T{sub max}). C{sub max} was 13.34 {mu}g/ml for the AZT-glucuronide (AZT-G) and was 0.023 {mu}g/ml for the potentially toxic minor metabolite 3'-amino-3'-deoxythymidine (AMT), both occurring at about 1 h after dosing. Similar elimination half-times, 0.70 and 0.68 h{sup -1}, were found for AZT and AZT-G, respectively, while 3TC was eliminated about half as fast (0.33 h{sup -1}) resulting in AUC{sub (0-{infinity})} values of 6.97 {mu}g/ml h for 3TC, 2.99 {mu}g/ml h for AZT, 20.5 {mu}g/ml h for AZT-G and 0.002 for AMT 6.97 {mu}g/ml h. This study shows similar metabolism and pharmacokinetics for oral administration of AZT/3TC in the adult patas monkey, other primate species and humans. The data validate the use of the patas monkey for studies of NRTI toxicity.« less

Modeling and Demonstrating Regenerative Braking of a Squirrel Cage Induction Motor with Various Deceleration Rates Using V by F Control

DTIC Science & Technology

2010-06-01

DEMONSTRATING REGENERATIVE BRAKING OF A SQUIRREL CAGE INDUCTION MOTOR WITH VARIOUS DECELERATION RATES USING V BY F CONTROL by Billy J. Nytko...Regenerative Braking of a Squirrel Cage Induction Motor with Various Deceleration Rates Using V by F Control 6. AUTHOR(S) Billy J. Nytko 5. FUNDING...Naval Postgraduate School (NPS) to model regenerative braking to support energy conservation technologies and to improve the efficiencies within the

Evidence for a single class of somatostatin receptors in ground squirrel cerebral cortex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krantic, S.; Petrovic, V.M.; Quirion, R.

1989-01-01

In the present study we characterized high-affinity somatostatin (SRIF) binding sites (Kd = 2.06 +/- 0.32 nM and Bmax = 295 +/- 28 fmol/mg protein) in cerebral cortex membrane preparations of European ground squirrel using /sup 125/I-(Tyr0-D-Trp8)-SRIF14 as a radioligand. The inhibition of radioligand specific binding by SRIF14, as well as by its agonists (SRIF28, Tyr0-D-Trp8-SRIF14, SMS 201 995) was complete and monophasic, thus revealing a single population of somatostatinergic binding sites. Radioautographic analysis of /sup 125/I-(Tyr0-D-Trp8)-SRIF14 labeled brain sections confirmed the results of our biochemical study. The homogeneity of SRIF binding sites in the ground squirrel neocortex was notmore » dependent on the animal's life-cycle phase.« less

Subtle changes in brain functions produced by single doses of mevinphos (Phosdrin).

DOT National Transportation Integrated Search

1973-02-01

Mevinphos (Phosdrin) was found to inhibit the amplitude of hippocampal evoked potentials in unanesthetized squirrel monkeys with chronically indwelling electrodes. The threshold dose was 0.050 mg/kg and the maximal dose studied was 0.200 mg/kg. Doses...

Clustering of PCOS-like traits in naturally hyperandrogenic female rhesus monkeys.

PubMed

Abbott, D H; Rayome, B H; Dumesic, D A; Lewis, K C; Edwards, A K; Wallen, K; Wilson, M E; Appt, S E; Levine, J E

2017-04-01

Do naturally occurring, hyperandrogenic (≥1 SD of population mean testosterone, T) female rhesus monkeys exhibit traits typical of women with polycystic ovary syndrome (PCOS)? Hyperandrogenic female monkeys exhibited significantly increased serum levels of androstenedione (A4), 17-hydroxyprogesterone (17-OHP), estradiol (E2), LH, antimullerian hormone (AMH), cortisol, 11-deoxycortisol and corticosterone, as well as increased uterine endometrial thickness and evidence of reduced fertility, all traits associated with PCOS. Progress in treating women with PCOS is limited by incomplete knowledge of its pathogenesis and the absence of naturally occurring PCOS in animal models. A female macaque monkey, however, with naturally occurring hyperandrogenism, anovulation and polyfollicular ovaries, accompanied by insulin resistance, increased adiposity and endometrial hyperplasia, suggests naturally occurring origins for PCOS in nonhuman primates. As part of a larger study, circulating serum concentrations of selected pituitary, ovarian and adrenal hormones, together with fasted insulin and glucose levels, were determined in a single, morning blood sample obtained from 120 apparently healthy, ovary-intact, adult female rhesus monkeys (Macaca mulatta) while not pregnant or nursing. The monkeys were then sedated for somatometric and ultrasonographic measurements. Female monkeys were of prime reproductive age (7.2 ± 0.1 years, mean ± SEM) and represented a typical spectrum of adult body weight (7.4 ± 0.2 kg; maximum 12.5, minimum 4.6 kg). Females were defined as having normal (n = 99) or high T levels (n = 21; ≥1 SD above the overall mean, 0.31 ng/ml). Electronic health records provided menstrual and fecundity histories. Steroid hormones were determined by tandem LC-MS-MS; AMH was measured by enzymeimmunoassay; LH, FSH and insulin were determined by radioimmunoassay; and glucose was read by glucose meter. Most analyses were limited to 80 females (60 normal T, 20 high T) in

Germline transmission in transgenic Huntington's disease monkeys.

PubMed

Moran, Sean; Chi, Tim; Prucha, Melinda S; Ahn, Kwang Sung; Connor-Stroud, Fawn; Jean, Sherrie; Gould, Kenneth; Chan, Anthony W S

2015-07-15

Transgenic nonhuman primate models are an increasingly popular model for neurologic and neurodegenerative disease because their brain functions and neural anatomies closely resemble those of humans. Transgenic Huntington's disease monkeys (HD monkeys) developed clinical features similar to those seen in HD patients, making the monkeys suitable for a preclinical study of HD. However, until HD monkey colonies can be readily expanded, their use in preclinical studies will be limited. In the present study, we confirmed germline transmission of the mutant huntingtin (mHTT) transgene in both embryonic stem cells generated from three male HD monkey founders (F0) and in second-generation offspring (F1) produced via artificial insemination by using intrauterine insemination technique. A total of five offspring were produced from 15 females that were inseminated by intrauterine insemination using semen collected from the three HD founders (5 of 15, 33%). Thus far, sperm collected from the HD founder (rHD8) has led to two F1 transgenic HD monkeys with germline transmission rate at 100% (2 of 2). mHTT expression was confirmed by quantitative real-time polymerase chain reaction using skin fibroblasts from the F1 HD monkeys and induced pluripotent stem cells established from one of the F1 HD monkeys (rHD8-2). Here, we report the stable germline transmission and expression of the mHTT transgene in HD monkeys, which suggest possible expansion of HD monkey colonies for preclinical and biomedical research studies. Copyright © 2015 Elsevier Inc. All rights reserved.

Spontaneous Metacognition in Rhesus Monkeys.

PubMed

Rosati, Alexandra G; Santos, Laurie R

2016-09-01

Metacognition is the ability to think about thinking. Although monitoring and controlling one's knowledge is a key feature of human cognition, its evolutionary origins are debated. In the current study, we examined whether rhesus monkeys (Macaca mulatta; N = 120) could make metacognitive inferences in a one-shot decision. Each monkey experienced one of four conditions, observing a human appearing to hide a food reward in an apparatus consisting of either one or two tubes. The monkeys tended to search the correct location when they observed this baiting event, but engaged in information seeking-by peering into a center location where they could check both potential hiding spots-if their view had been occluded and information seeking was possible. The monkeys only occasionally approached the center when information seeking was not possible. These results show that monkeys spontaneously use information about their own knowledge states to solve naturalistic foraging problems, and thus provide the first evidence that nonhumans exhibit information-seeking responses in situations with which they have no prior experience. © The Author(s) 2016.

Pentatrichomonas hominis: prevalence and molecular characterization in humans, dogs, and monkeys in Northern China.

PubMed

Li, Wen-Chao; Ying, Meng; Gong, Peng-Tao; Li, Jian-Hua; Yang, Ju; Li, He; Zhang, Xi-Chen

2016-02-01

Pentatrichomonas hominis is an anaerobic amitochondrial flagellated protist that primarily colonizes the large intestines of a number of species, including cats, dogs, nonhuman primates, and humans. The prevalence of this parasite in dogs, monkeys, and humans is, however, poorly understood. In this study, a total of 362 fecal samples including 252 dogs, 60 monkeys, and 50 humans from northern China were collected for an epidemiological survey of P. hominis infection.The average prevalence of P. hominis infection determined by nested PCR was 27.38% (69/252), 4.00% (2/50), and 46.67% (28/60) in dogs, humans, and monkeys, respectively. The prevalence was significantly higher in 6-month-old dogs (41.53%) and children (7.69%) than in older dogs (14.39%) and adults (0%) (P < 0.05). Sequencing of amplicons revealed that four variable positions separated sequences into three types, called CC1-3. CC1 was the most prevalent in the study population. This study determined that P. hominis infection is common in dogs, monkeys, and humans, especially in children and young dogs. Given the infection prevalence, P. hominis may pose a risk of zoonotic and anthroponotic transmission.

Effects of short-term niacin treatment on plasma lipoprotein concentrations in African green monkeys (Chlorocebus aethiops).

PubMed

Chauke, Chesa G; Arieff, Zainunisha; Kaur, Mandeep; Seier, Jurgen V

2014-02-01

Niacin is the most effective drug available for raising levels of high-density lipoprotein (HDL) cholesterol. To evaluate its effects on plasma lipid concentrations, the authors administered a low dose of niacin to healthy, adult, female African green monkeys for 3 months. In the treated monkeys, low-density lipoprotein cholesterol concentrations decreased by 43% from baseline, whereas concentrations of HDL cholesterol and apolipoprotein A-I increased by 49% and 34%, respectively. The results suggest that in this primate model, a low dose of niacin can effectively increase concentrations of HDL cholesterol.

Bilirubin photoisomers in rhesus monkey serum.

PubMed

Okada, Hitoshi; Itoh, Susumu; Nii, Kohichiroh; Sugino, Masashiro; Fuke, Noriko; Koyano, Kosuke; Yasuda, Saneyuki; Kusaka, Takashi

2018-05-23

As rhesus monkeys exhibit physiological jaundice during the neonatal period, we used rhesus monkey serum to examine changes in bilirubin photoisomers. Bilirubin-rhesus monkey serum solution was irradiated with blue light-emitting diode, and changes in the absorbance and bilirubin fraction were compared with those in bilirubin- human serum albumin (HSA) and bilirubin-rat albumin solutions. The λ max decreased with light irradiation. The mean production rate of cyclobilirubin IXα was 1.98, 199 and 0.76 × 10 -2 /min in rhesus monkey serum, HSA and rat albumin, respectively. There was no significant difference between rhesus monkey serum and HSA. The (ZE)-bilirubin IXα/(ZZ)-bilirubin IXα ratio was 0.33, 0.45, and 0.10, respectively, differing significantly among the groups. The (EZ)-bilirubin IXα/(ZZ)-bilirubin IXα ratio was 0.020, 0.010, and 0.062, respectively, with no significant difference between rhesus monkey serum and HSA. The production rate of (EZ)-cyclobilirubin XIIIα(= (ZE)-cyclobilirubin XIIIα) was 0.73, 1.60, and 0.51 × 10 -2 /min, respectively, with differing significantly among the groups. The (EZ)-bilirubin IIIα/(ZZ)-bilirubin IIIα ratio was significantly different among the groups at 0.20, 0.38, and 0.15, respectively. This is the first report demonstrating the photoisomerization of bilirubin in rhesus monkey serum and the animal with the same cyclobilirubin production rate as HSA.Rhesus monkeys may be used as an animal model for neonatal hyperbilirubinemia in humans to evaluate the efficacy of phototherapy. Copyright © 2018 Elsevier B.V. All rights reserved.

Corticobulbar projections from distinct motor cortical areas to the reticular formation in macaque monkeys.

PubMed

Fregosi, Michela; Contestabile, Alessandro; Hamadjida, Adjia; Rouiller, Eric M

2017-06-01

Corticospinal and corticobulbar descending pathways act in parallel with brainstem systems, such as the reticulospinal tract, to ensure the control of voluntary movements via direct or indirect influences onto spinal motoneurons. The aim of this study was to investigate the corticobulbar projections from distinct motor cortical areas onto different nuclei of the reticular formation. Seven adult macaque monkeys were analysed for the location of corticobulbar axonal boutons, and one monkey for reticulospinal neurons' location. The anterograde tracer BDA was injected in the premotor cortex (PM), in the primary motor cortex (M1) or in the supplementary motor area (SMA), in 3, 3 and 1 monkeys respectively. BDA anterograde labelling of corticobulbar axons were analysed on brainstem histological sections and overlapped with adjacent Nissl-stained sections for cytoarchitecture. One adult monkey was analysed for retrograde CB tracer injected in C5-C8 hemispinal cord to visualise reticulospinal neurons. The corticobulbar axons formed bilateral terminal fields with boutons terminaux and en passant, which were quantified in various nuclei belonging to the Ponto-Medullary Reticular Formation (PMRF). The corticobulbar projections from both PM and SMA tended to end mainly ipsilaterally in PMRF, but contralaterally when originating from M1. Furthermore, the corticobulbar projection was less dense when originating from M1 than from non-primary motor areas (PM, SMA). The main nuclei of bouton terminals corresponded to the regions where reticulospinal neurons were located with CB retrograde tracing. In conclusion, the corticobulbar projection differs according to the motor cortical area of origin in density and laterality. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Late winter and early spring home range and habitat use of the endangered Carolina northern flying squirrel in western North Carolina

USGS Publications Warehouse

Ford, W. Mark; Kelly, Christine A.; Rodrigue, Jane L.; Odom, Richard H.; Newcomb, Douglas; Gilley, L. Michelle; Diggins, Corinne A.

2014-01-01

The Carolina northern flying squirrel Glaucomys sabrinus coloratus is an endangered subspecies that is restricted to high elevation forests in the southern Appalachian Mountains. Owing to rugged terrain and nocturnal habits, the subspecies’ natural history, home range characteristics and habitat preferences are poorly known. We radio-tracked 3 female and 2 male Carolina northern flying squirrels during late winter through spring 2012 in the Pisgah National Forest, North Carolina, USA. Tracked squirrels used 13 yellow birch Betula alleghaniensis and 9 red spruce Picea rubens as diurnal dens. Ten of the yellow birch dens were in cavities, whereas the remainders were dreys. Conversely, 8 of the red spruce dens were dreys and one was in a cavity. Mean (±SE) female 95 and 50% adaptive kernel home ranges were 6.50 ± 2.19 and 0.93 ± 0.33 ha, respectively, whereas the corresponding values for males were 12.6 ± 0.9 and 1.45 ± 0.1 ha, respectively. Squirrels used red spruce stands with canopies >20 m more than expected based on availability at the landscape and home range scales. Results should be interpreted cautiously because of small sample sizes and seasonal observations; however, they provide evidence that although northern hardwoods such as yellow birch are an important den habitat component, mature red spruce-dominated habitats with complex structure provide foraging habitats and are also den habitat. Our findings support efforts to improve the structural condition of extant red spruce forests and/or increase red spruce acreage to potentially benefit Carolina northern flying squirrels.

The effects of feedback lighting on the circadian drinking rhythm in the diurnal new world primate Saimiri sciureus

NASA Technical Reports Server (NTRS)

Ferraro, J. S.; Sulzman, F. M.

1988-01-01

Feedback lighting provides illumination primarily during the subjective night (i.e., the photosensitive portion of the circadian cycle) in response to a given behavior. This technique has previously been used to test the nonparametric model of entrainment in nocturnal rodents. In three species (Rattus norvegicus, Mesocricetus auratus, and Mus musculus), the free-running period of the locomotor activity rhythm was similar whether the animals were exposed to continuous light or discrete light pulses occurring essentially only during the subjective night (i.e., feedback lighting). In the current experiments, feedback lighting was presented to squirrel monkeys so that light fell predominantly during the subjective night. Feedback lighting was linked to the drinking behavior in this diurnal primate so that when the animal drank, the lights went out. Despite the seemingly adverse predicament, the monkeys maintained regular circadian drinking rhythms. Furthermore, just as the period of the free-running activity rhythms of nocturnal rodents exposed to continuous light or feedback lighting were similar, the period of the drinking rhythms of the squirrel monkeys in continuous light and feedback lighting were comparable (25.6 +/- 0.1 and 25.9 +/- 0.1 hours, respectively), despite a substantial decrease in the total amount of light exposure associated with feedback lighting. The free-running period of monkeys exposed to continuous dark (24.5 +/- 0.1 hours) was significantly shorter than either of the two lighting conditions (P < 0.001). The results presented for the drinking rhythm were confirmed by examination of the temperature and activity rhythms. Therefore, discrete light pulses given predominately during the subjective night are capable of simulating the effects of continuous light on the free-running period of the circadian rhythms of a diurnal primate. The response of squirrel monkeys to feedback lighting thus lends further support for the model and suggests that the

Rhesus monkey heart rate during exercise

NASA Technical Reports Server (NTRS)

Delorge, J.; Thach, J. S., Jr.

1972-01-01

Various schedules of reinforcement and their relation to heart rates of rhesus monkeys during exercise are described. All the reinforcement schedules produced 100 per cent or higher increments in the heart rates of the monkeys during exercise. Resting heart rates were generally much lower than those previously reported, which was attributed to the lack of physical restraint of the monkeys during recording.

Get the Monkey off Your Back

ERIC Educational Resources Information Center

Ciabattini, David; Custer, Timothy J.

2008-01-01

Monkeys are the problems that need solutions, the tasks that need to be accomplished, the decisions that need to be made, and the actions that need to be taken. According to a theory, people carry monkeys around on their backs until they can successfully shift their burden to someone else and the monkey leaps from one back to the next. Managers…

Segregating the Effects of Seed Traits and Common Ancestry of Hardwood Trees on Eastern Gray Squirrel Foraging Decisions.

PubMed

Sundaram, Mekala; Willoughby, Janna R; Lichti, Nathanael I; Steele, Michael A; Swihart, Robert K

2015-01-01

The evolution of specific seed traits in scatter-hoarded tree species often has been attributed to granivore foraging behavior. However, the degree to which foraging investments and seed traits correlate with phylogenetic relationships among trees remains unexplored. We presented seeds of 23 different hardwood tree species (families Betulaceae, Fagaceae, Juglandaceae) to eastern gray squirrels (Sciurus carolinensis), and measured the time and distance travelled by squirrels that consumed or cached each seed. We estimated 11 physical and chemical seed traits for each species, and the phylogenetic relationships between the 23 hardwood trees. Variance partitioning revealed that considerable variation in foraging investment was attributable to seed traits alone (27-73%), and combined effects of seed traits and phylogeny of hardwood trees (5-55%). A phylogenetic PCA (pPCA) on seed traits and tree phylogeny resulted in 2 "global" axes of traits that were phylogenetically autocorrelated at the family and genus level and a third "local" axis in which traits were not phylogenetically autocorrelated. Collectively, these axes explained 30-76% of the variation in squirrel foraging investments. The first global pPCA axis, which produced large scores for seed species with thin shells, low lipid and high carbohydrate content, was negatively related to time to consume and cache seeds and travel distance to cache. The second global pPCA axis, which produced large scores for seeds with high protein, low tannin and low dormancy levels, was an important predictor of consumption time only. The local pPCA axis primarily reflected kernel mass. Although it explained only 12% of the variation in trait space and was not autocorrelated among phylogenetic clades, the local axis was related to all four squirrel foraging investments. Squirrel foraging behaviors are influenced by a combination of phylogenetically conserved and more evolutionarily labile seed traits that is consistent with a weak

Pharmacokinetics of doxylamine, a component of Bendectin, in the rhesus monkey.

PubMed

Slikker, W; Holder, C L; Lipe, G W; Bailey, J R; Young, J F

1989-01-01

The elimination of doxylamine and metabolites was determined after iv administration of [14C]doxylamine succinate at 0.7 and 13.3 mg/kg to the adult female rhesus monkey. Although the total recovery of radioactivity was the same for the low- and high-dose studies (90.2%), the rate of plasma elimination of doxylamine and its demethylated metabolite (desmethyldoxylamine) was slower for the high dose group. The 24 hr urinary excretion of doxylamine metabolites, desmethyl- and didesmethyldoxylamine, was significantly increased and the polar doxylamine metabolites were significantly decreased as the iv doxylamine succinate dose was increased. The plasma elimination of gas chromatograph (GC)-detected doxylamine was determined after oral administration of Bendectin (doxylamine succinate and pyridoxine hydrochloride) at 7, 13.3, and 27 mg/kg to adult female rhesus monkeys. As the dose increased, the clearance of doxylamine decreased. A statistically evaluated fit of the oral data to a single-compartment, parallel first-order elimination model and a single-compartment, parallel first- and second-order (Michaelis-Menten) elimination model indicated that the more complex model containing the second-order process was most consistent with the observed elimination data.