German Primate Center Research Articles

Gross morphometry of the heart of the Common marmoset

The Callithrix jacchus is a Brazilian endemic species that has been widely used as an experimental model in biomedical research. Anatomical data are necessary to support experimental studies with this species. Eleven hearts of C. jacchus from the German Primate Centre (DPZ) have been studied in order to characterize their gross morphometry and compare them with other animal models and human. Biometric data were also obtained. The mean values for morphometry of the hearts did not show any significant difference between male and female. The relative heart weight was similar to human, bovine and equine species. Considering those aspects, the C. jacchus could be used as non-human primate experimental model for biomedical studies on heart.

Minimally invasive transabdominal collection of preimplantation embryos from the common marmoset monkey (Callithrix jacchus)

A novel, minimally invasive, transabdominal embryo collection method (transabdominal method) was developed as an alternative to a standard abdominal incision for embryo collection in the common marmoset. The abdominal incision method was used for 304 flushes using 36 female animals, whereas the transabdominal method was used for 488 flushes using 48 females; successful embryo collection rates were 48.0% and 48.4% (P > 0.05), respectively. These techniques were successfully duplicated at another institute (German Primate Center, DPZ). At that institution, successful embryo collection rates were 88.9% and 77.8% for the abdominal incision and transabdominal methods, respectively (P > 0.05), whereas the average numbers of preimplantation embryos obtained per flush were (mean ± SD) 1.91 ± 0.35 and 1.71 ± 0.14 (P > 0.05). The transabdominal method reduced animal stress, did not require incisional wound healing, and enabled successive embryo recoveries to be done much sooner. More embryos in early developmental stages (zygotes/morulae) were recovered using the transabdominal method (76.1%) than the abdominal incision method (52.6%, P < 0.01). In contrast, recovery of arrested or abnormal embryos was not significantly different between these two methods (9.8% and 8.3%). To verify developmental ability of embryos recovered by the transabdominal method, transfer of 28 normal embryos to 14 surrogate mothers yielded a nidation rate of 57%. Five females sustained term pregnancies and eight neonates were born. This novel transabdominal method will facilitate progress in marmoset developmental biology and embryology.

Characterization of the 10q26-orthologue in rhesus monkeys corroborates a functional connection between ARMS2 and HTRA1

Age-related macular degeneration, which is the leading cause of blindness in industrialized countries, is a multifactorial, degenerative disorder of the macula with strong heritability. For age-related macular degeneration in humans, the genes ARMS2 and HTRA1 in the region 10q26 are both promising candidates for being involved in pathogenesis. However, the associated variants are located in a region of strong linkage disequilibrium and so far, the identification of the causative gene in humans was not yet possible. This dilemma might be solved using an appropriate model organism. Rhesus monkeys suffer from drusen, a major hallmark of age-related macular degeneration, and the drusen-phenotype shares susceptibility factors with human macular degeneration. Thus, the rhesus monkey represents a natural animal model to uncover genetic factors leading to macular degeneration. Moreover, the existence of genetically homogenous cohorts offers an excellent opportunity to determine risk factors. However, the 10q26-orthologue genomic region in rhesus monkeys is not characterized in detail so far. Therefore, the aim of this study is to analyze the rhesus linkage disequilibrium structure and to investigate whether variants in ARMS2 or HTRA1 are associated with the drusen-phenotype as well. We sequenced parts of a 20 kb region around ARMS2 and HTRA1 in a genetically homogeneous cohort of 91 rhesus monkeys descending from the CPRC rhesus cohort on Cayo Santiago and currently housed in the German Primate Centre in Göttingen. Within this group, ophthalmoscopic examinations revealed a naturally high drusen prevalence of about 47% in monkeys >5 years. We detected 56 genetic variants within and around ARMS2 and HTRA1 and, as one deviates from Hardy-Weinberg-Equilibrium, 55 polymorphisms were used to generate a linkage disequilibrium-Plot and to perform association studies. We observed strong linkage disequilibrium between the markers and were able to define two haplotype blocks. One of these blocks spanned the whole ARMS2 locus and the 5′ part of HTRA1 – almost perfectly resembling the situation found in humans. Tests for association revealed a variant in the promoter region of HTRA1 and two variants in the 5′-UTR of ARMS2 to be associated with drusen. The strong linkage disequilibrium inhibits – as in humans – a determination of the risk gene using statistical methods only. However, the conserved linkage disequilibrium structure in humans and macaques goes in line with the recently emerged dual causality model proposing that ARMS2 and HTRA1 are functionally connected and that both genes contribute to the disease pathology. Moreover, the characterization of the 10q26-orthologue genomic region of the rhesus monkey provides a basis for now needed functional investigations in a well-characterized model organism.

On the impact of oscillatory synchrony on directed functional connectivity metrics: a network-model-based study

Event Abstract Back to Event On the impact of oscillatory synchrony on directed functional connectivity metrics: a network-model-based study Agostina Palmigiano1, 2*, Demian Battaglia1, 2, Annette Witt1, 2, 3 and Theo Geisel1, 2 1 Max Planck Intitute for Dynamics and Self-Organization, Non linear Dynamics, Germany 2 Bernstein Center for Computational Neuroscience, Germany 3 German Primate Center, Germany Perception, cognition and behavior require flexible communication and coordination between brain circuits. Experimental and theoretical evidence (Womelsdorf et al. 2007; Battaglia et al., 2012) show that phase locking between the oscillatory activity of different brain areas or local circuits may underlie the self-organized instantiation of effective communication channels. From a data analysis perspective, causal influences between different neuronal populations are often inferred from time series of neural activity obtained through electrophysiological recordings or imaging techniques using methods like Granger Causality or Transfer Entropy. However, the depiction of inter-areal interactions provided by such indirect "black-box" approaches is difficult to interpret, because the underlying network dynamics associated to the recorded signals is known only partially or is completely hidden. Furthermore different metrics are not guaranteed but in special conditions to infer matching causal connectivities (aka directed functional connectivities). We consider here the dynamics of a toy system of two coupled (unidirectionally or bidirectionally) neural populations, described as large networks of spiking excitatory and inhibitory neurons with realistic heterogeneous parameters. By varying systematically the degree of synchronization of the resulting network activity and the strength of inter-population coupling, we explore the performance in different dynamical regimes of different causality metrics in inferring the underlying inter-population coupling from semi-realistic synthetic spike trains, LFPs and other imaging signals with different spatial and temporal resolutions. More specifically, we identify under which conditions linear techniques fail in providing a correct inference of the ongoing population interaction and we comment on possible practical strategies to overcome their limitations. Acknowledgements This project is supported by the grant BMBF Grant 01GQ1005B (BCCN Goettingen) References [1] Womelsdorf T et al (2007) Science 316: 1609-1612. [2] Buehlmann A, Deco G (2010) PLoS Comp Biol 6. [3] Battaglia D, Witt A, Wolf F, Geisel T (2012) PLoS Comp Biol (in press). [4] Barnett L, Barrett AB, Seth AK (2009) Phys Rev Lett 103:238701. Keywords: causality, functional connectivity, network oscillations, synchronization Conference: Bernstein Conference 2012, Munich, Germany, 12 Sep - 14 Sep, 2012. Presentation Type: Poster Topic: Other Citation: Palmigiano A, Battaglia D, Witt A and Geisel T (2012). On the impact of oscillatory synchrony on directed functional connectivity metrics: a network-model-based study. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference 2012. doi: 10.3389/conf.fncom.2012.55.00175 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 18 Sep 2012; Published Online: 12 Sep 2012. * Correspondence: Miss. Agostina Palmigiano, Max Planck Intitute for Dynamics and Self-Organization, Non linear Dynamics, Goettingen, 37077, Germany, apalmigiano@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Agostina Palmigiano Demian Battaglia Annette Witt Theo Geisel Google Agostina Palmigiano Demian Battaglia Annette Witt Theo Geisel Google Scholar Agostina Palmigiano Demian Battaglia Annette Witt Theo Geisel PubMed Agostina Palmigiano Demian Battaglia Annette Witt Theo Geisel Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Asymmetric generalization of target jump adaptation suggests tuning changes at the level of motor goals -- a neuronal network simulation

Event Abstract Back to Event Asymmetric generalization of target jump adaptation suggests tuning changes at the level of motor goals -- a neuronal network simulation Stephanie Westendorff1, 2, Shenbing Kuang1, Opher Donchin3 and Alexander Gail1, 2* 1 German Primate Center, Germany 2 Bernstein Center for Computational Neuroscience, Germany 3 Ben-Gurion University of the Negev, Israel We previously presented a behavioral target jump paradigm (Westendorff et al., 2010), in which reach movements reliably adapted to target error alone, without prediction error caused by perturbed feedback about the hand position. The target jump task induced adaptation with an asymmetric generalization, i.e. reach corrections for the adapted target were transferred more strongly towards unperturbed probe targets which lay in the direction of the target jump, compared to probe targets in the opposite direction. We here present a three-layer recurrent neuronal network with which we can simulate the reach adaptation behavior of the target jump paradigm. The presented model was previously used for simulating context-specific sensorimotor transformations (Brozovic, 2007) and needed only minor modifications for simulating the target jump task. After learning a 1-to-1 standard mapping from spatially local sensory input to a congruent motor output across the whole workspace, the model was re-trained at a single spatial position to perform a 15º rotation of the motor output relative to the local sensory input. In this adapted state the generalization of adaptation effects to unperturbed probe target locations was measured equivalently to human psychophysics. We analyzed the changes in the neuronal tuning properties at the different levels of the model in response to the induced target jump adaptation. The model reproduces the asymmetry in generalization observed in the experimental data. The strength of the asymmetry is dependent on the tuning width of neurons in the output layer, but can be robustly found over a wide range of parameters. The asymmetry of generalization is contingent upon changes of tuning properties in the hidden layer. If tuning changes in the hidden layer were prevented, than the model still adapted to the local target jump but showed symmetric generalization, which does not match the psychophysical results. This implies that adaptation in the learning model is achieved by changes in the mapping from the input to the hidden layer, rather than changes in the mapping from the hidden to the output layer. Our results suggest that adaptation in our target jump task likely affects motor goal representations at early visuospatial stages of reach planning, rather than changes at the motor execution level. The simulations predict specific changes of tuning properties in areas like the posterior parietal cortex during target jump adaptation. References Brozovic et al. 2007 JNeurosci:27:10588. Westendorff et al 2011 Soc Neurosci Abstr 292.8 Keywords: adaptation, generalization, motor goal, Neurons, networks and dynamical systems, reach, target jump Conference: BC11 : Computational Neuroscience & Neurotechnology Bernstein Conference & Neurex Annual Meeting 2011, Freiburg, Germany, 4 Oct - 6 Oct, 2011. Presentation Type: Poster Topic: neurons, networks and dynamical systems (please use "neurons, networks and dynamical systems" as keywords) Citation: Westendorff S, Kuang S, Donchin O and Gail A (2011). Asymmetric generalization of target jump adaptation suggests tuning changes at the level of motor goals -- a neuronal network simulation. Front. Comput. Neurosci. Conference Abstract: BC11 : Computational Neuroscience & Neurotechnology Bernstein Conference & Neurex Annual Meeting 2011. doi: 10.3389/conf.fncom.2011.53.00050 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 23 Aug 2011; Published Online: 04 Oct 2011. * Correspondence: Dr. Alexander Gail, German Primate Center, Göttingen, Germany, agail@gwdg.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Stephanie Westendorff Shenbing Kuang Opher Donchin Alexander Gail Google Stephanie Westendorff Shenbing Kuang Opher Donchin Alexander Gail Google Scholar Stephanie Westendorff Shenbing Kuang Opher Donchin Alexander Gail PubMed Stephanie Westendorff Shenbing Kuang Opher Donchin Alexander Gail Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Optimization of the input impedance of a low-noise unipolar powered amplifier

Recording systems in neurophysiological research have to deal with high sensor impedances of 1 MΩ and above, while having pretty low signal amplitudes of several μV. In cooperation with the German Primate Center Göttingen the Institute of Electromechanical Design develops a wireless recording system which can be carried by animals. Since common circuits and electrical parts for noise reduction used in stationary on-the-shelf systems are too space demanding for our device, we designed a simple input stage with an instrumental amplifier followed by cascade of programmable gain amplifiers.The widespread approach of dimensioning the amplifier's input resistance as high as possible has appreciable disadvantages in design of compact mobile recording systems, such as leakage currents and parasitic resistances. Furthermore thermal noise increases significantly for broadband recordings. We could show, that accepting lower input impedance leads to an almost optimal signal to noise ratio and reduces design troubles for mobile devices.

Induced Roelofs effect in reaching

Event Abstract Back to Event Induced Roelofs effect in reaching Bahareh Taghizadeh1 and Alexander Gail1, 2* 1 German Primate Center, Germany 2 Bernstein Center for Computational Neuroscience, Germany Goal-directed reaching requires accurate localization of the target object. But the localization of visual objects is prone to illusions induced by the visual context. In the induced Roelofs effect (IRE), the position of a task irrelevant visual object induces a shift in the localization of the visual target object. This is true when subjects have to indicate the position of the target object relative to an array of reference positions, e.g. by response keys or by pointing to it with delay. In contrast, when subjects in the same task indicate the position of the target object by pointing to it without instructed delay or by directly reaching towards it with or without delay, no IRE is induced [1]. This discrepancy was taken as evidence for separate visuospatial representations for direct sensorimotor processing compared to spatial cognitive processing [2]. Here we test if an IRE can also be induced for reaching movement towards the target stimulus, which would argue against such strictly separate processing. We asked human subjects to perform reaches towards visual target stimuli in the frontoparallel plane. Each trial started with a brief appearance of a reference array (RA) of five horizontally arranged boxes which indicated the potential target positions. Then the target and a surrounding task-irrelevant visual frame were flashed, followed by a decision array (DA) immediately after the cue/frame offset. The DA was identical to the RA, but could be placed at different positions on the screen. While keeping ocular fixation, subjects had to reach towards the DA box which corresponded to the RA box in which they had seen the flashed target. The results showed a reliable IRE for reaching. In our task the reach goal needed to be defined relative to a task-relevant object, i.e. in an object-based reference frame, while in previous experiments the reach goal was directly defined by the target objects. The results suggest that during object-based encoding of motor goal locations, the information of additional task-irrelevant objects can induce systematic mis-localizations of the reach goal. This finding argues against strictly separate visuospatial representations for direct sensorimotor processing compared to spatial cognitive processing.

Non-human primates in outdoor enclosures: Risk for infection with rodent-borne hantaviruses

Different species of non-human primates have been exploited as animal disease models for human hantavirus infections. To study the potential risk of natural hantavirus infection of non-human primates, we investigated serum samples from non-human primates of three species living in outdoor enclosures of the German Primate Center (GPC), Göttingen, located in a hantavirus endemic region of central Germany. For that purpose we used serological assays based on recombinant antigens of the bank vole ( Myodes glareolus) transmitted Puumala virus (PUUV) and the common and field vole ( Microtus arvalis, Microtus agrestis) associated Tula virus (TULV) which are both broadly geographically distributed in Germany. In 24 out of 251 (9.6%) monkey sera collected in 2006 PUUV- and/or TULV-reactive immunoglobulin G (IgG) antibodies were detected. Investigation of follow-up sera from 13 animals confirmed for two animals a seroconversion due to hantavirus exposure at the GPC. To prove the origin of the infection, wild rodents from the surrounding regions were analyzed by hantavirus-specific reverse transcriptase-PCR analysis. In 6 of the 73 investigated bank voles and 3 of the 19 investigated Microtus spp. PUUV- and TULV-specific nucleic acid sequences, respectively, were detected. In conclusion, our investigations demonstrate for the first time natural infections of non-human primates in outdoor enclosures in Germany. These findings highlight the importance of hantavirus surveillance in those primate housings and corresponding preventive measures against wild rodents, particularly in hantavirus endemic regions.

Generalization patterns during reach adaptation to target jump

Event Abstract Back to Event Generalization patterns during reach adaptation to target jump Stephanie Westendorff1*, Bahareh Taghizadeh1 and Alexander Gail1 1 German Primate Center, Sensorimotor Group, BCCN Göttingen, Germany In typical visuomotor rotation tasks, adaptation is induced by a mismatch between visual and proprioceptive sensory input. Target-jump paradigms, i.e. tasks with sudden displacement of the movement target during movement initiation or execution, do not induce cross-modal mismatch, nor do they induce adaptation when subject are aware of the displacement. Here we present and characterize a novel target jump paradigm, in which reach movements reliably get adapted to target displacements. Subjects had to make center-out reaches to a peripheral target. Simultaneously they had to make a saccade to a neutral target. Saccadic suppression during the eye movement allowed us to displace the reach target during hand movement initiation or execution, without subjects noticing the perturbation. The reach target was displaced either to a different eccentricity (radial displacement) or to a different angular (directional displacement).Subjects incrementally adapted to the radial and to the directional displacement, with average learning rates similar to prism adaptation, and showed reliable negative aftereffects.We also tested the generalization of the adaptation effect to neighboring reach targets. Subjects were first adapted to either a radial or directional target displacement, and then probed at different positions along the radius and circumference of the adapted target. Preliminary analysis of our results suggests that movement endpoints to novel targets are off-set by a vector that is approximately equal to the displacement vector imposed on the adapted target. The offset decreases with increasing angular or radial distance from the adapted target.Our results show that reach adaptation in a target-jump experiment is possible when the displacement is obscured by a simultaneous saccade to a different target. The observed generalization patterns may be difficult to explain as a combination of independent adjustments on the direction and extent of movement. Consequently, our results may cast doubt on an earlier claim that direction and extent of movements are planned independently (Krakauer, Pine, Ghilardi, and Ghez, J Neurosci, 2000). Figure 1: Reach endpoint adaptation to 15º directional target jump. Reach errors are shown as angular deviation over trials for 6 subjects. Figure 1 Keywords: computational neuroscience Conference: Bernstein Conference on Computational Neuroscience, Berlin, Germany, 27 Sep - 1 Oct, 2010. Presentation Type: Presentation Topic: Bernstein Conference on Computational Neuroscience Citation: Westendorff S, Taghizadeh B and Gail A (2010). Generalization patterns during reach adaptation to target jump. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference on Computational Neuroscience. doi: 10.3389/conf.fncom.2010.51.00018 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 22 Sep 2010; Published Online: 23 Sep 2010. * Correspondence: Dr. Stephanie Westendorff, German Primate Center, Sensorimotor Group, BCCN Göttingen, Göttingen, Germany, swesten@gwdg.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Stephanie Westendorff Bahareh Taghizadeh Alexander Gail Google Stephanie Westendorff Bahareh Taghizadeh Alexander Gail Google Scholar Stephanie Westendorff Bahareh Taghizadeh Alexander Gail PubMed Stephanie Westendorff Bahareh Taghizadeh Alexander Gail Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Decision making in the Posterior Parietal Cortex: A neural field model

Event Abstract Back to Event Decision making in the Posterior Parietal Cortex: A neural field model Christian Klaes1*, Sebastian Schneegans2, Gregor Schöner2 and Alexander Gail3 1 Bernstein Center for Computational Neuroscience Goettingen, German Primate Center, Germany 2 Ruhr-Universität-Bochum, Institut für Neuroinformatik, Germany 3 Deutsches Primatenzentrum, Sensorimotor Group, Germany The process of decision making often involves incomplete information about the outcome of the decision. In order to plan goal-directed reaching, it is necessary to combine sensory information about goal positions with information about the current behavioral context to select an appropriate action. A central role in this process is attributed to the posterior parietal cortex (PPC), which has been associated with value based selection of action and perceptual decision making. As an underlying mechanism, it has been proposed that the selection and specification of possible actions are not two distinct, sequential operations, but that instead the decision for an action emerges from the competition between different movement plans1. Here, we present a neural field model2 to describe the dynamics of action selection in the PPC, developed in parallel with an electrophysiological study in monkeys3. The task required rule-based spatial remapping of a motor goal, which was indicated by a spatial cue, depending on a contextual cue. The model can learn the context-dependent remapping task via an implemented Hebbian-style learning rule. It is trained from a pre-structured initial state (with default cue-response mapping behavior), using a training procedure that emulates the training procedure of the monkeys. The trained model developed activity patterns and neuronal tunings consistent with the empirical data. We then examined how actions are planned in the absence of an explicit rule, i.e. with no contextual cue. In this case the model showed a decision bias towards one goal (Fig. 1a) or an equal representation of both potential goals (Fig. 1b), depending on the input statistics during training. The model remained susceptible to later experience and changes of the reward schedule. This matches the observations in monkeys performing the same task and it provides an account for the formation of action plans under ambiguous conditions. The field model provides an integrated account for the operations of sensorimotor transformations, working memory, and action selection required for decision making. Figure 1: Activity in the PPC layer of the model. A spatial cue is presented at the probe direction (PD). The remapped direction (RD) is the position that the model previously learned to be the valid goal, when an additional contextual cue was presented. The time axis shows the memory period from onset of the transient spatial cue until just before the goal is to be selected (go cue). When exposed to 80 % remapped motor goals and 20 % direct mapped goals, the model develops a bias towards the remapped direction (RD), when tested in a free choice trial (a). If the ratio is 50/50, both potential motor goals are equally represented (b). Figure 1

X Chromosomal Variation Is Associated with Slow Progression to AIDS in HIV-1-Infected Women

AIDS has changed from a mostly male-specific health problem to one that predominantly affects females. Although sex differences in HIV-1 susceptibility are beyond doubt, the extent to which sex affects the onset and progression of AIDS has remained elusive. Here, we provide evidence for an influence of X chromosomal variation on the course of retroviral infection, both in HIV-1-infected patients and in the rhesus macaque model of AIDS. A two-stage, microsatellite-based GWAS of SIV-infected monkeys revealed MHC class I markers and a hitherto-unknown X chromosomal locus as being associated with a nominal score measuring progression to AIDS (Fisher's exact p < 10(-6)). The X chromosomal association was subsequently confirmed in HIV-1-infected patients with published SNP genotype data. SNP rs5968255, located at human Xq21.1 in a conserved sequence element near the RPS6KA6 and CYLC1 genes, was identified as a significant genetic determinant of disease progression in females (ANOVA p = 8.8 x 10(-5)), but not in males (p = 0.19). Heterozygous female carriers of the C allele showed significantly slower CD4 cell decline and a lower viral load at set point than TT homozygous females and than males. Inspection of HapMap revealed that the CT genotype is significantly more frequent among Asians than among Europeans or Africans. Our results suggest that, in addition to the individual innate and adaptive immunity status, sex-linked genetic variation impacts upon the rate of progression to AIDS. Elucidating the mechanisms underlying this sex-specific effect will promote the development of antiretroviral therapies with high efficacy in both sexes.

Outbreak of Streptococcus equi subsp. zooepidemicus infection in a group of rhesus monkeys (Macaca mulatta)

Background A severe upper respiratory tract infection occurred in a breeding group of rhesus monkeys housed together in one of six indoor/outdoor corals of the German Primate Center. The clinical signs of the disease included severe purulent conjunctivitis, rhinitis, pharyngitis, respiratory distress and lethargy. Six of 45 animals died within a few days after developing signs of infection. Methods and results Histopathologic and microbiologic examinations of the dead animals were consistent with a severe fibrinopurulent bronchopneumonia. Microbiology revealed a Lancefield group C streptococcus identified as Streptococcus equi subsp. zooepidemicus as the causative agent of infection. Conclusions The infection was passed on from animal to animal but did not spread to the other five breeding groups nearby. Extensive diagnostic testing failed to reveal the consisting presence of copathogens in individual cases. A visitor with upper respiratory disease was suspected as source of infection.

Attentional modulation of the tuning of neurons in area MT to the direction of transparent motion

Event Abstract Back to Event Attentional modulation of the tuning of neurons in area MT to the direction of transparent motion Anja Lochte1*, Valeska Stephan1, Vladislav Kozyrev1, 2, Annette Witt2, 3 and Stefan Treue1 1 German Primate Center, Germany 2 Bernstein Center for Computational Neuroscience, Germany 3 Max Planck Institute for Dynamics and Self-Organization , Germany Transparent motion perception requires the segmentation and separate representation of multiple motion directions within the same part of visual space. In a previous study we recorded responses from direction-selective neurons in macaque middle temporal area (MT) to unattended bidirectional random dot patterns (RDPs; Treue et al., 2000). The profile of responses to such transparent motion patterns is the scaled sum of responses to the individual components, showing two peaks when the angle between the component directions exceeds the neuron’s tuning width.Here we investigated the influence of attention on the representation of the direction components of transparent motion by recording from MT in an attentional paradigm. Our question was, whether the effects of attention can be better characterized as a modulation of the population response in MT or as a modulation of two independent neuronal populations, each encoding one of the two directions (as might be expected to happen in area V1). Two monkeys were trained on a task, where an initial cue indicated the relevant direction of motion in a given trial. Two RDPs were then presented, moving within a common stationary aperture, sized and positioned to fit within the classical receptive field. While maintaining gaze on a fixation point, the animals were instructed to respond to a speed increment within the cued surface. In a sensory condition, the monkeys were asked to respond to a luminance change of the fixation point. By systematically varying the overall pattern direction, tuning curves were measured with a constant relative angle of 120 degrees between the component directions. The activity profile across 90 MT units showed two peaks corresponding to the two stimulus configurations in which one of the directions moved in the neuron’s preferred direction. The profile can be well fit by the sum of two Gaussians, enabling a quantitative comparison of neuronal responses for the attended versus the sensory condition. The fitted tuning curves showed an average increase of 52% around the peak where the preferred direction was attended relative to the sensory condition. For the peak corresponding to the condition when the preferred direction was unattended, we observed an average suppression of 5%. Neither of the fitted individual Gaussians showed a change in tuning width. Our results, supported by preliminary numerical modeling, show that attending to one surface in a transparent motion stimulus causes a direction-dependent modulation of the population response in MT, representing the neural correlate of attentional allocation to an individual surface.Acknowledgments: The project was supported by the Volkswagen Foundation (grant I/79868) and by grant 01GQ0433 from the Federal Ministry of Education and Research to the Bernstein Center for Computational Neuroscience Goettingen. Conference: Bernstein Conference on Computational Neuroscience, Frankfurt am Main, Germany, 30 Sep - 2 Oct, 2009. Presentation Type: Poster Presentation Topic: Sensory processing Citation: Lochte A, Stephan V, Kozyrev V, Witt A and Treue S (2009). Attentional modulation of the tuning of neurons in area MT to the direction of transparent motion. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference on Computational Neuroscience. doi: 10.3389/conf.neuro.10.2009.14.154 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 28 Aug 2009; Published Online: 28 Aug 2009. * Correspondence: Anja Lochte, German Primate Center, Göttingen, Germany, alochte@gwdg.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Anja Lochte Valeska Stephan Vladislav Kozyrev Annette Witt Stefan Treue Google Anja Lochte Valeska Stephan Vladislav Kozyrev Annette Witt Stefan Treue Google Scholar Anja Lochte Valeska Stephan Vladislav Kozyrev Annette Witt Stefan Treue PubMed Anja Lochte Valeska Stephan Vladislav Kozyrev Annette Witt Stefan Treue Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Influence of attention on encoding of two spatially separated motion patterns by neurons in area MT

Influence of attention on encoding of two spatially separated motion patterns by neurons in area MT

Multiplicative changes in area MST neuron's responses of primate visual cortex by spatial attention

Event Abstract Back to Event Multiplicative changes in area MST neuron's responses of primate visual cortex by spatial attention Sonia Baloni1, 2*, Daniel Kaping2 and Stefan Treue2 1 Bernstein Center for Computational Neuroscience, Germany 2 German Primate Center, Germany Spatial attention has been shown to create multiplicative enhancements of orientation tuning curves in area V4 and of direction tuning curves of area MT of primate visual cortex. We similarly, aimed to study attentional effects on tuning profiles of MST neurons, which are tuned for spiral motion space (SMS) directions. The SMS, introduced by Graziano et al. (1994), is a circular dimension that considers expansion, clockwise rotation, contraction and counterclockwise rotation as cardinal directions in this space, with a continuum of stimuli in between.We recorded SMS tuning curves from 123 MST neurons of two macaque monkeys. The monkeys were trained to attend to a target stimulus, a SMS random dot pattern (RDP) in the presence of another RDP (distractor). One of the RDP was placed in the receptive field (RF) while the other was placed outside, in the opposite hemifield. In a given trial the two RDPs moved in the same direction, picked randomly from one of twelve SMS directions and either the stimulus inside (attention-in condition) or outside (attention-out condition) the RF was the designated target. The monkeys had to report a speed change of the target stimulus while ignoring all other changes. The tuning profile of individual MST neurons can be well fitted by a Gauss function, allowing a quantitative comparison of neuronal responses to the stimulus inside the RF, when it is behaviorally relevant (attended target stimulus) or irrelevant (unattended distractor).We found that directing spatial attention into the RF enhances the response of MST neurons to optimized SMS multiplicatively (average +30%). The robust responses of MST neurons to SMS stimuli away from the preferred direction can be used to test between two alternative attentional modulation models. In the activity gain model, attention multiplicatively modulates the overall responses of neurons. Because the given activity level evoked by a particular stimulus is modulated independent of the neuron’s baseline firing rate, the given activity is multiplied by a fixed factor. An alternative to the activity gain model is the response gain model in which attention only modulates the additional activity evoked by a given stimulus leaving a neuron’s “baseline” response unmodulated.We modified the Gaussian tuning function by holding all parameters to the values obtained for the attention-out condition while introducing a single attentional multiplication factor, either multiplying the entire function (activity gain) or all parameters but the baseline (response gain). The fits are all well correlated with the data and because the two functions have a similar form they are highly correlated. A partial correlation between the fitted activity and response gain data revealed that many more cells were better fit by the activity gain model.In summary, responses in MST are multiplicatively enhanced when spatial attention is directed into the RF. This effect is best accounted for by activity gain models where the overall response of the neuron is modulated by a constant factor. Conference: Bernstein Conference on Computational Neuroscience, Frankfurt am Main, Germany, 30 Sep - 2 Oct, 2009. Presentation Type: Poster Presentation Topic: Information processing in neurons and networks Citation: Baloni S, Kaping D and Treue S (2009). Multiplicative changes in area MST neuron's responses of primate visual cortex by spatial attention. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference on Computational Neuroscience. doi: 10.3389/conf.neuro.10.2009.14.045 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Aug 2009; Published Online: 26 Aug 2009. * Correspondence: Sonia Baloni, Bernstein Center for Computational Neuroscience, Göttingen, Germany, sbaloni@gwdg.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sonia Baloni Daniel Kaping Stefan Treue Google Sonia Baloni Daniel Kaping Stefan Treue Google Scholar Sonia Baloni Daniel Kaping Stefan Treue PubMed Sonia Baloni Daniel Kaping Stefan Treue Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Validation of non-fluorescent methods to reliably detect acrosomal and plasma membrane integrity of common marmoset (Callithrix jacchus) sperm

Simple, rapid and stable sperm evaluation methods which have been optimized for common marmoset (Callithrix jacchus) are critical for studies involving collection and evaluation of sperm in the field. This is particularly important for new species groups such as Callitrichidae where the sperm have been little studied. Of this family, C. jacchus is the best known, and has been chosen as a model species for other members of the genus Callithrix. The fundamental evaluation parameters for sperm of any species are viability and acrosomal status. Semen samples were collected by penile vibratory stimulation. To evaluate sperm plasma membrane integrity, Eosin-Nigrosin was tested here for the common marmoset sperm to be used under field conditions. Further, a non-fluorescent stain for acrosome, the "Simple" stain, developed for domestic and wild cats, was tested on common marmoset sperm. This was compared with a fluorescent staining, Fluorescein isothiocyanate-Pisum sativum agglutinin (FITC-PSA), routinely used and validated for common marmoset at the German Primate Centre to evaluate acrosomal integrity. Results obtained with the "Simple" stain showed a marked differentiation between sperm with intact and non-intact acrosome both with and without ionophore treatment and closely correlated with results obtained with FITC-PSA. Temperature had no effect on the results with the "Simple" stain and the complete processing is simple enough to be carried out under field conditions. These findings indicated that the "Simple" stain and Eosin-Nigrosin provide rapid and accurate results for C. jacchus sperm and that those methods can be reliably used as field tools for sperm evaluation for this species.

The International Max Planck Research Schools for Molecular Biology and Neurosciences in Göttingen (Germany) as Examples for Joint Doctoral Training by a German University and its Non‐university Partners

New concepts of higher education have recently been implemented through the MSc/PhD programmes in Molecular Biology and Neurosciences in the International Max Planck Research Schools, due to close cooperation between the University of Gottingen, three Max Planck Institutes and the German Primate Centre. The novel measures include a three stage selection of applicants, structured PhD training in English, doctoral thesis committees, and comprehensive services and support for the international student community. All university and non‐university faculty members are equally involved in training, supervision, and examinations. The close cooperation significantly improved synergies between the participating institutions and led to new collaborations within the Gottingen science community.

Attention reshapes center-surround receptive-field structure in Macaque cortical area MT

Event Abstract Back to Event Attention reshapes center-surround receptive-field structure in Macaque cortical area MT Katharina Anton-Erxleben1*, Valeska Stephan1 and Stefan Treue1 1 German Primate Center, Germany Directing spatial attention to a location inside the classical receptive field (cRF) of a neuron in macaque medial temporal area (MT) has been shown to shift the center of the cRF towards the attended location. Here we investigate the influence of spatial attention on the profile of the inhibitory surround present in many MT neurons. Two monkeys were trained to attend to the fixation point or to one of two random dot patterns (RDPs) placed at equal eccentricity inside or next to the cRF, while a third RDP (the probe) was briefly presented in quick succession at regularly spaced positions spanning the receptive field center and surround. Mean responses to probe presentation at the different positions were used to compute a map of the excitatory receptive field and its inhibitory surround. We find that attention systematically reshapes the receptive field profile, significantly and independently shifting both center and inhibitory surround towards the attended location. Furthermore, size of the cRF is changed as a function of relative distance of the attentional focus: attention inside the cRF shrinks it, while directing attention next to the cRF expands it. In addition, we find systematic changes in surround inhibition and cRF amplitude. This non-multiplicative push-pull modulation of the receptive field's center-surround structure by attention optimizes processing at and near the attentional focus to strengthen the representation of the attended stimulus while reducing influences from distractors. Conference: Bernstein Symposium 2008, Munich, Germany, 8 Oct - 10 Oct, 2008. Presentation Type: Poster Presentation Topic: All Abstracts Citation: Anton-Erxleben K, Stephan V and Treue S (2008). Attention reshapes center-surround receptive-field structure in Macaque cortical area MT. Front. Comput. Neurosci. Conference Abstract: Bernstein Symposium 2008. doi: 10.3389/conf.neuro.10.2008.01.024 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 13 Nov 2008; Published Online: 13 Nov 2008. * Correspondence: Katharina Anton-Erxleben, German Primate Center, Göttingen, Germany, k.antonerxleben@web.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Katharina Anton-Erxleben Valeska Stephan Stefan Treue Google Katharina Anton-Erxleben Valeska Stephan Stefan Treue Google Scholar Katharina Anton-Erxleben Valeska Stephan Stefan Treue PubMed Katharina Anton-Erxleben Valeska Stephan Stefan Treue Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Neurogenesis in the adult brain: is there an association with mental disorders?

Within the last two decades, our view of the mature mammalian brain has changed. The brain is far from being fixed and immutable, as a multitude of factors such as environmental stimulation, learning, growth factors, glucocorticoids and sexual hormones, stress, aging, and neurotransmitters such as glutamate and serotonin regulate generation of new neurons; also many drugs have an impact on neurogenesis in selected brain regions such as the subgranular zone of the hippocampal dentate gyrus and the subventricular zone of the lateral ventricles. This newfound capacity has forced a new look at plasticity of the brain, an organ previously considered to have a stable structure. The term neural plasticity summarizes dynamic processes that constitute the capacity of neural systems, single neurons, glia cells, synapses, receptors, and other components to adapt and change their structural or functional repertoire in response to alterations in the internal and/or external environment. Neural plasticity is mandatory for adequate functioning of an individual in the continuously changing environment. However, as demonstrated e.g., in brains of patients with mood disorders it became clear that neural plastic processes are not always beneficial. The discovery of stem cells in the adult brain and of adult neurogenesis has added new dimensions to neuroplasticity research. Moreover, it raises questions regarding the underlying mechanisms of the newly generated neurons, and how they influence the functioning of established neuronal networks. The magnitude and ubiquity of adult neurogenesis across vertebrates suggests that it is an essential process and not merely a residue of development. The functional implications of adult neurogenesis are still a matter of debate, but several reports provide evidence, although so far only correlational, that neurogenesis in the adult dentate gyrus might be involved in learning and memory processes. Moreover, new theories have linked neuropsychiatric disorders such as depression, schizophrenia, dementia, and drug addiction to a failure of adult neurogenesis. The hippocampus is one of the brain structures that has been extensively studied with regard to the consequences of stress, depression, and antidepressant actions. Recent imaging studies in humans revealed that the hippocampus undergoes selective volume reduction in stress-related neuropsychiatric disorders such as recurrent depressive illness. Today there is compelling experimental evidence that reduced dentate neurogenesis and hippocampal volume loss in animal models of depression can be reversed by antidepressant treatment. These findings caused the formulation of the novel concept that reduced neurogenesis may contribute to the pathogenesis of depression. However, the exact mechanisms responsible for the hippocampal volume loss in major depression are so far unclear. In their article Czeh and Lucassen state that neuronal loss can be excluded as cause for the volume loss. As apoptosis and reduced neurogenesis contribute only to a very limited extent to the observed volume loss other factors such as alterations in the glial, dendritic, axonal, and synaptic compartments are discussed to contribute to the hippocampal shrinkage. Together with shifts in both the extracellular space and fluid volume theses factors may provide a mechanistic explanation for the obE. Fuchs (&) Clinical Neurobiology Laboratory German Primate Center Kellnerweg 4 37077 Goettingen, Germany Tel.: +49-551/385-1130 E-Mail: efuchs@gwdg.de

Epizootic of Tularemia in an Outdoor Housed Group of Cynomolgus Monkeys (Macaca fascicularis)

Tularemia is a highly contagious infectious zoonosis, transmissible by inoculation, ingestion, or inhalation of the infectious agent Francisella tularensis. The disease is perpetuated by infected rodents, blood-sucking arthropods, and by contaminated water. Therefore, nonhuman primates housed outdoors may be at risk for exposure. An epizootic of F. tularensis occurred in an indoor/outdoor-housed group of cynomolgus monkeys (Macaca fascicularis) at the German Primate Center. Tularemia was diagnosed in 18 out of 35 animals within a period of 2 years. Six animals died with unspecific clinical symptoms; 12 animals developed seroconversion and were still alive. Pathologic findings were similar in all monkeys that died and resembled the clinical picture of the human disease, including an ulceroglandular syndrome with local lymphadenopathy, gingivostomatitis, and systemic spread, with manifestations such as subacute necrotizing hepatitis, granulomatous splenitis, and pneumonia. Tularemia was diagnosed by culture, real-time polymerase chain reaction, and ELISA techniques. This is the largest outbreak in nonhuman primates and the first report of tularemia in cynomolgus monkeys. An overview of the recent literature about tularemia in nonhuman primates is given.