Center for Behavioral Brain Science

Magdeburg, Germany

Center for Behavioral Brain Science

Magdeburg, Germany
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Edelmann E.,Otto Von Guericke University of Magdeburg | Lessmann V.,Otto Von Guericke University of Magdeburg | Lessmann V.,Center for Behavioral Brain science | Brigadski T.,Otto Von Guericke University of Magdeburg | Brigadski T.,Center for Behavioral Brain science
Neuropharmacology | Year: 2014

Overwhelming evidence collected since the early 1990's strongly supports the notion that BDNF is among the key regulators of synaptic plasticity in many areas of the mammalian central nervous system. Still, due to the extremely low expression levels of endogenous BDNF in most brain areas, surprisingly little data i) pinpointing pre- and postsynaptic release sites, ii) unraveling the time course of release, and iii) elucidating the physiological levels of synaptic activity driving this secretion are available. Likewise, our knowledge regarding pre- and postsynaptic effects of endogenous BDNF at the single cell level in mediating long-term potentiation still is sparse. Thus, our review will discuss the data currently available regarding synaptic BDNF secretion in response to physiologically relevant levels of activity, and will discuss how endogenously secreted BDNF affects synaptic plasticity, giving a special focus on spike timing-dependent types of LTP and on mossy fiber LTP. We will attempt to open up perspectives how the remaining challenging questions regarding synaptic BDNF release and action might be addressed by future experiments. This article is part of the Special Issue entitled 'BDNF Regulation of Synaptic Structure, Function, and Plasticity'. © 2013 Elsevier Ltd. All rights reserved.

Fischer A.,Otto Von Guericke University of Magdeburg | Fischer A.,Max Planck Institute for Neurological Research | Ullsperger M.,Otto Von Guericke University of Magdeburg | Ullsperger M.,Donders Institute for Brain | And 2 more authors.
Neuron | Year: 2013

The ability to learn not only from experienced but alsofrom merely fictive outcomes without direct rewarding or punishing consequences should improve learning and resulting value-guided choice. Using an instrumental learning task in combination with multiple single-trial regression of predictions derived from a computational reinforcement-learning model on human EEG, we found an early temporospatial double dissociation in the processing of fictive and real feedback. Thereafter, real and fictive feedback processing converged at a common final path, reflected in parietal EEG activity that was predictive of future choices. In the choice phase, similar parietal EEG activity related to certainty of the impending response was predictive for the decision on the next trial as well. These parietal EEG effects may reflect a common adaptive cortical mechanism of updating or strengthening of stimulus values by integrating outcomes, learning rate, and certainty, which is active during both decision making and evaluation. Neuronal processing of real (rewarding, punishing) and fictive action outcomes (which would have happened had one acted differently) differs for 400ms and then converges on a common adaptive mechanism driving future decision making and learning

Wiener J.M.,Bournemouth University | de Condappa O.,Bournemouth University | Harris M.A.,Bournemouth University | Harris M.A.,University of Edinburgh | And 2 more authors.
Journal of Neuroscience | Year: 2013

Efficient spatial navigation requires not only accurate spatial knowledge but also the selection of appropriate strategies. Using a novel paradigm that allowed us to distinguish between beacon, associative cue, and place strategies, we investigated the effects of cognitive aging on the selection and adoption of navigation strategies in humans. Participants were required to rejoin a previously learned route encountered from an unfamiliar direction. Successful performance required the use of an allocentric place strategy, which was increasingly observed in young participants over six experimental sessions. In contrast, older participants,whowere able to recall the routewhen approaching intersections from the same direction as during encoding, failed to use the correct place strategy when approaching intersections from novel directions. Instead, they continuously used a beacon strategy and showed no evidence of changing their behavior across the six sessions. Given that this bias was already apparent in the first experimental session, the inability to adopt the correct place strategy is not related to an inability to switch from a firmly established response strategy to an allocentric place strategy. Rather, and in line with previous research, age-related deficits in allocentric processing result in shifts in preferred navigation strategies and an overall bias for response strategies. The specific preference for a beacon strategy is discussed in the context of a possible dissociation between beacon-based and associative-cue-based response learning in the striatum, with the latter being more sensitive to age-related changes. © 2013 the authors.

Hoffmann M.B.,Otto Von Guericke University of Magdeburg | Hoffmann M.B.,Center for Behavioral Brain science | Dumoulin S.O.,University Utrecht
Trends in Neurosciences | Year: 2015

Sensory systems project information in a highly organized manner to the brain, where it is preserved in maps of the sensory structures. These sensory projections are altered in congenital abnormalities, such as anophthalmia, albinism, achiasma, and hemihydranencephaly. Consequently, these abnormalities, profoundly affect the organization of the visual system. Surprisingly, visual perception remains largely intact, except for anophthalmia. Recent brain imaging advances shed light on the mechanisms that underlie this phenomenon. In contrast to animal models, in humans the plasticity of thalamocortical connections appears limited, thus demonstrating the importance of cortical adaptations. We suggest that congenital visual pathway abnormalities provide a valuable model to investigate the principles of plasticity that make visual representations available for perception and behavior in humans. © 2014 Elsevier Ltd.

Fischer A.G.,Otto Von Guericke University of Magdeburg | Jocham G.,Center for Behavioral Brain science | Ullsperger M.,Otto Von Guericke University of Magdeburg | Ullsperger M.,Center for Behavioral Brain science | Ullsperger M.,Radboud University Nijmegen
Trends in Cognitive Sciences | Year: 2015

Neuroscientists have been puzzled by the fact that acute administration of a selective serotonin reuptake inhibitor (SSRI) produces results that are, at times, compatible with either decreases or increases in serotonergic neurotransmission. Furthermore, the underlying cause of the delayed onset of antidepressant effects of SSRI treatment has remained obscure. It has recently been reported that serotonergic raphe neurons co-release glutamate and that serotonergic and glutamatergic components constitute a dual signal with behaviorally distinct effects. We discuss the consequences of these novel findings and propose a framework for understanding the controversial effects of acute SSRI administration. Furthermore, we suggest that the delayed remedial onset of SSRI treatment could be explained by an initial reduction of the glutamatergic component of the dual serotonergic signal. © 2014 Elsevier Ltd.

Shine J.P.,German Center for Neurodegenerative Diseases | Valdes-Herrera J.P.,German Center for Neurodegenerative Diseases | Hegarty M.,University of California at Santa Barbara | Wolbers T.,German Center for Neurodegenerative Diseases | Wolbers T.,Center for Behavioral Brain science
Journal of Neuroscience | Year: 2016

Spatial navigation is a multisensory process involving integration of visual and body-based cues. In rodents, head direction (HD) cells, which are most abundant in the thalamus, integrate these cues to code facing direction. Human fMRI studies examining HD coding in virtual environments (VE) have reported effects in retrosplenial complex and (pre-)subiculum, but not the thalamus. Furthermore, HD coding appeared insensitive to global landmarks. These tasks, however, provided only visual cues for orientation, and attending to global landmarks did not benefit task performance. In the present study, participants explored a VE comprising four separate locales, surrounded by four global landmarks. To provide body-based cues, participants wore a head-mounted display so that physical rotations changed facing direction in the VE. During subsequent MRI scanning, subjects saw stationary views of the environment and judged whether their orientation was the same as in the preceding trial. Parameter estimates extracted from retrosplenial cortex and the thalamus revealed significantly reduced BOLD responses when HD was repeated. Moreover, consistent with rodent findings, the signal did not continue to adapt over repetitions of the same HD. These results were supported by a whole-brain analysis showing additional repetition suppression in the precuneus. Together, our findings suggest that: (1) consistent with the rodent literature, the human thalamus may integrate visual and body-based, orientation cues; (2) global reference frame cues can be used to integrate HD across separate individual locales; and (3) immersive training procedures providing full body-based cues may help to elucidate the neural mechanisms supporting spatial navigation. © 2016 the authors.

Riemer M.,German Center for Neurodegenerative Diseases | Diersch N.,German Center for Neurodegenerative Diseases | Bublatzky F.,University of Mannheim | Wolbers T.,German Center for Neurodegenerative Diseases | Wolbers T.,Center for Behavioral Brain science
NeuroImage | Year: 2016

The mental representations of space, time, and number magnitude are inherently linked. The right posterior parietal cortex (PPC) has been suggested to contain a general magnitude system that underlies the overlap between various perceptual dimensions. However, comparative studies including spatial, temporal, and numerical dimensions are missing. In a unified paradigm, we compared the impact of right PPC inhibition on associations with spatial response codes (i.e., Simon, SNARC, and STARC effects) and on congruency effects between space, time, and numbers. Prolonged cortical inhibition was induced by continuous theta-burst stimulation (cTBS), a protocol for transcranial magnetic stimulation (TMS), at the right intraparietal sulcus (IPS).Our results show that congruency effects, but not response code associations, are affected by right PPC inhibition, indicating different neuronal mechanisms underlying these effects. Furthermore, the results demonstrate that interactions between space and time perception are reflected in congruency effects, but not in an association between time and spatial response codes. Taken together, these results implicate that the congruency between purely perceptual dimensions is processed in PPC areas along the IPS, while the congruency between percepts and behavioral responses is independent of this region. © 2016 Elsevier Inc..

Daniel R.,Otto Von Guericke University of Magdeburg | Daniel R.,Princeton University | Pollmann S.,Otto Von Guericke University of Magdeburg | Pollmann S.,Center for Behavioral Brain science
Neurobiology of Learning and Memory | Year: 2014

Reinforcement learning enables organisms to adjust their behavior in order to maximize rewards. Electrophysiological recordings of dopaminergic midbrain neurons have shown that they code the difference between actual and predicted rewards, i.e., the reward prediction error, in many species. This error signal is conveyed to both the striatum and cortical areas and is thought to play a central role in learning to optimize behavior. However, in human daily life rewards are diverse and often only indirect feedback is available. Here we explore the range of rewards that are processed by the dopaminergic system in human participants, and examine whether it is also involved in learning in the absence of explicit rewards. While results from electrophysiological recordings in humans are sparse, evidence linking dopaminergic activity to the metabolic signal recorded from the midbrain and striatum with functional magnetic resonance imaging (fMRI) is available. Results from fMRI studies suggest that the human ventral striatum (VS) receives valuation information for a diverse set of rewarding stimuli. These range from simple primary reinforcers such as juice rewards over abstract social rewards to internally generated signals on perceived correctness, suggesting that the VS is involved in learning from trial-and-error irrespective of the specific nature of provided rewards. In addition, we summarize evidence that the VS can also be implicated when learning from observing others, and in tasks that go beyond simple stimulus-action-outcome learning, indicating that the reward system is also recruited in more complex learning tasks. © 2014 Elsevier Inc.

Endrass T.,Otto Von Guericke University of Magdeburg | Endrass T.,Center for Behavioral Brain science | Ullsperger M.,Otto Von Guericke University of Magdeburg | Ullsperger M.,Center for Behavioral Brain science | Ullsperger M.,Radboud University Nijmegen
Neuroscience and Biobehavioral Reviews | Year: 2014

Obsessive-compulsive disorder (OCD) is characterized by overactivity in frontal and striatal brain regions, and event-related potential studies have shown increased brain activity during performance monitoring. The error-related negativity (ERN) is a component of the event-related potential that is observed following incorrect responses, and signals the need for behavioral adjustments. ERN enhancements have even been considered as a biomarker or endophenotype of OCD. However over the past years, enhanced ERN amplitudes, although less reliably, were also found in anxiety and affective disorders. These results question the specificity of ERN alterations to OCD. The present review summarizes current findings on performance monitoring and feedback processing in OCD and their relation to behavioral measures. Further, it discusses possible differential mechanisms contributing to amplitude variations in different clinical conditions. © 2014 Elsevier Ltd.

Ullsperger M.,Otto Von Guericke University of Magdeburg | Ullsperger M.,Center for Behavioral Brain science | Ullsperger M.,Radboud University Nijmegen | Fischer A.G.,Otto Von Guericke University of Magdeburg | And 5 more authors.
Trends in Cognitive Sciences | Year: 2014

Successful goal-directed behavior critically depends on performance monitoring, a set of cognitive and affective functions determining whether adaptive control is needed and, if so, which type and magnitude is required. Knowledge of the brain structures involved in such a process has grown enormously, although the time course of performance-monitoring (PM) activity remains poorly understood. Here, we review evidence from EEG recordings in humans and show that monitored events elicit a rather uniform sequence of cortical activity reflecting the detection, accumulation, and weighting of evidence for the necessity to adapt and (re)act. We link the EEG findings with invasive and pharmacological findings and evaluate the neurobiological plausibility of current theories of PM. © 2014 Elsevier Ltd.

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