Search

Delusions of control in schizophrenia are characterized by the striking feeling that one's actions are controlled by external forces. We here tested qualitative predictions inspired by Bayesian causal inference models, which suggest that such misattributions of agency should lead to decreased intentional binding. Intentional binding refers to the phenomenon that subjects perceive a compression of time between their intentional actions and consequent sensory events. We demonstrate that patients with delusions of control perceived less self-agency in our intentional binding task. This effect was accompanied by significant reductions of intentional binding as compared to healthy controls and patients without delusions. Furthermore, the strength of delusions of control tightly correlated with decreases in intentional binding. Our study validated a critical prediction of Bayesian accounts of intentional binding, namely that a pathological reduction of the prior likelihood of a causal relation between one's actions and consequent sensory events--here captured by delusions of control--should lead to lesser intentional binding. Moreover, our study highlights the import of an intact perception of temporal contiguity between actions and their effects for the sense of agency. [ABSTRACT FROM AUTHOR]

While traditional theories of sensorimotor processing have often assumed a serial decision-making pipeline, more recent approaches have suggested that multiple actions may be planned concurrently and vie for execution. Evidence for the latter almost exclusively stems from electrophysiological studies in posterior parietal and premotor cortex of monkeys. Here we study concurrent prospective motor planning in humans by recording functional magnetic resonance imaging (fMRI) during a delayed response task engaging movement sequences towards multiple potential targets. We find that also in human posterior parietal and premotor cortex delay activity modulates both with sequence complexity and the number of potential targets. We tested the hypothesis that this modulation is best explained by concurrent prospective planning as opposed to the mere maintenance of potential targets in memory. We devise a bounded rationality model with information constraints that optimally assigns information resources for planning and memory for this task and determine predicted information profiles according to the two hypotheses. When regressing delay activity on these model predictions, we find that the concurrent prospective planning strategy provides a significantly better explanation of the fMRI-signal modulations. Moreover, we find that concurrent prospective planning is more costly and thus limited for most subjects, as expressed by the best fitting information capacities. We conclude that bounded rational decision-making models allow relating both behavior and neural representations to utilitarian task descriptions based on bounded optimal information-processing assumptions. Author summary: When the future is uncertain, it can be beneficial to concurrently plan several action possibilities in advance. Electrophysiological research found evidence in monkeys that brain regions in posterior parietal and promotor cortex are indeed capable of planning several actions in parallel. We now used fMRI to study brain activity in these brain regions in humans. For our analyses we applied bounded rationality models that optimally assign information resources to fMRI activity in a complex motor planning task. We find that theoretical information costs of concurrent prospective planning explained fMRI activity profiles significantly better than assuming alternative memory-based strategies. Moreover, exploiting the model allowed us to quantify the individual capacity limit for concurrent planning and to relate these individual limits to both subjects' behavior and to their neural representations of planning. [ABSTRACT FROM AUTHOR]

The static magnetic field of MRI scanners can induce a magneto-hydrodynamic stimulation of the vestibular organ (MVS). In common fMRI settings, this MVS effect leads to a vestibular ocular reflex (VOR). We asked whether - beyond inducing a VOR - putting a healthy subject in a 3T MRI scanner would also alter goal-directed spatial behavior, as is known from other types of vestibular stimulation. We investigated 17 healthy volunteers, all of which exhibited a rightward VOR inside the MRI-scanner as compared to outside-MRI conditions. More importantly, when probing the distribution of overt spatial attention inside the MRI using a visual search task, subjects scanned a region of space that was significantly shifted toward the right. An additional estimate of subjective straight-ahead orientation likewise exhibited a rightward shift. Hence, putting subjects in a 3T MRI-scanner elicits MVS-induced horizontal biases of spatial orienting and exploration, which closely mimic that of stroke patients with spatial neglect. [ABSTRACT FROM AUTHOR]

The recruitment of cross-hemispheric counterparts of lateralized prefrontal brain regions with increasing processing demand is thought to increase memory performance despite cognitive aging, but was recently reported to be present also in young adults working at their capacity limit. Here we ask if cross-hemispheric recruitment is a general strategy of the adult brain in that executive task demand would modulate bilateral activation beyond prefrontal cortex and across cognitive tasks. We analyzed data sets from two fMRI experiments investigating retrospective working memory maintenance and prospective action planning. We confirmed a cross-hemispheric recruitment of prefrontal cortex across tasks and experiments. Changes in lateralization due to planning further surfaced in the cerebellum, dorsal premotor and posterior parietal cortex. Parietal cortex thereby exhibited cross-hemispheric recruitment also during spatial but not verbal working memory maintenance. Our results confirm a domain-general role of prefrontal cortex in cross-hemispheric recruitment. They further suggest that other task-specific brain regions also recruit their idling cross-hemispheric counterparts to relocate executive processing power. [ABSTRACT FROM AUTHOR]

The recruitment of cross-hemispheric counterparts of lateralized prefrontal brain regions with increasing processing demand is thought to increase memory performance despite cognitive aging, but was recently reported to be present also in young adults working at their capacity limit. Here we ask if cross-hemispheric recruitment is a general strategy of the adult brain in that executive task demand would modulate bilateral activation beyond prefrontal cortex and across cognitive tasks. We analyzed data sets from two fMRI experiments investigating retrospective working memory maintenance and prospective action planning. We confirmed a cross-hemispheric recruitment of prefrontal cortex across tasks and experiments. Changes in lateralization due to planning further surfaced in the cerebellum, dorsal premotor and posterior parietal cortex. Parietal cortex thereby exhibited cross-hemispheric recruitment also during spatial but not verbal working memory maintenance. Our results confirm a domain-general role of prefrontal cortex in cross-hemispheric recruitment. They further suggest that other task-specific brain regions also recruit their idling cross-hemispheric counterparts to relocate executive processing power. [ABSTRACT FROM AUTHOR]

The processes underlying perceptual decision making are diverse and typically engage a distributed network of brain areas. It is a particular challenge to establish a sensory-to-motor functional hierarchy in such networks. This is because single-cell recordings mainly study the nodes of decision networks in isolation but seldom simultaneously. Moreover, imaging methods, which allow simultaneously accessing information from overall networks, typically suffer from either the temporal or the spatial resolution necessary to establish a detailed functional hierarchy in terms of a sequential recruitment of areas during a decision process. Here we report a novel analytical approach to work around these latter limitations: using temporal differences in human fMRI activation profiles during a tactile discrimination task with immediate versus experimentally delayed behavioral responses, we could derive a linear functional gradient across task-related brain areas in terms of their relative dependence on sensory input versus motor output. The gradient was established by comparing peak latencies of activation between the two response conditions. The resulting time differences described a continuum that ranged from zero time difference, indicative for areas that process information related to the sensory input and, thus, are invariant to the response delay instruction, to time differences corresponding to the delayed response onset, thus indicating motor-related processing. Taken together with our previous findings (Li Hegner et al. []: Hum Brain Mapp 36:3339-3350), our results suggest that the anterior insula reflects the ultimate perceptual stage within the uncovered sensory-to-motor gradient, likely translating sensory information into a categorical abstract (non-motor) decision. Hum Brain Mapp 38:1172-1181, 2017. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Summary Inhibition of action is commonly attributed to frontal cortex. A new study shows that intra-surgical stimulation of human posterior parietal cortex selectively prevents the initiation and execution of voluntary movement of the contralateral hand. Inhibition of action is commonly attributed to frontal cortex. A new study shows that intra-surgical stimulation of human posterior parietal cortex selectively prevents the initiation and execution of voluntary movement of the contralateral hand. [ABSTRACT FROM AUTHOR]

Perceptual decision making involves a distributed cortical network including areas related to sensory feature extraction, decision formation, and finally signalling the decision through a motor response. Although these processing steps are supposed to occur in sequence, the seemingly instant mapping of a perceptual decision onto a motor response renders these processes almost indistinguishable. To dissociate cortical areas related to sensory decision making from areas that prepare the subsequent motor response, we performed functional magnetic resonance imaging during a tactile spatial pattern discrimination task with interleaved immediate and delayed response conditions. Decision difficulty was manipulated parametrically by adding spatial noise to the tactile patterns, resulting in a rise in decision time with increasing noise. We assumed that areas involved in making the decision should show a variation in their activation with decision time and irrespective of whether (immediate response condition) or not (delayed response condition) a motor response could be prepared in advance. To exhibit these putative decision areas, we used response time, as was obtained in the immediate response condition, as parametric predictor for the difficulty-dependent variations of blood oxygenation level-dependent (BOLD)-activity in both response conditions. BOLD activations in right (contralateral) postcentral sulcus, right intraparietal sulcus (IPS) and bilateral anterior insula (aINS) reflected this parametric modulation in both response conditions, suggesting a role of these areas in tactile decisions independent of decision-specific motor preparation. Furthermore, a multivariate pattern analysis performed on the BOLD responses in the delayed response condition for a single difficulty level independently validated IPS and aINS as decision-related areas. Hum Brain Mapp 36:3339-3350, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

In this time-resolved functional magnetic resonance imaging (fMRI) study, we aimed to trace the neuronal correlates of covert planning processes that precede visually guided motor behavior. Specifically, we asked whether human posterior parietal cortex has prospective planning activity that can be distinguished from activity related to retrospective visual memory and attention. Although various electrophysiological studies in monkeys have demonstrated such motor planning at the level of parietal neurons, comparatively little support is provided by recent human imaging experiments. Rather, a majority of experiments highlights a role of human posterior parietal cortex in visual working memory and attention. We thus sought to establish a clear separation of visual memory and attention from processes related to the planning of goal-directed motor behaviors. To this end, we compared delayed-response tasks with identical mnemonic and attentional demands but varying degrees of motor planning. Subjects memorized multiple target locations, and in a random subset of trials targets additionally instructed (1) desired goals or (2) undesired goals for upcoming finger reaches. Compared with the memory/attention-only conditions, both latter situations led to a specific increase of preparatory fMRI activity in posterior parietal and dorsal premotor cortex. Thus, posterior parietal cortex has prospective plans for upcoming behaviors while considering both types of targets relevant for action: those to be acquired and those to be avoided. [ABSTRACT FROM AUTHOR]

For optimal response selection, the consequences associated with behavioral success or failure must be appraised. To determine how monetary consequences influence the neural representations of motor preparation, human brain activity was scanned with fMRI while subjects performed a complex spatial visuomotor task. At the beginning of each trial, reward context cues indicated the potential gain and loss imposed for correct or incorrect trial completion. FMRI-activity in canonical reward structures reflected the expected value related to the context. In contrast, motor preparatory activity in posterior parietal and premotor cortex peaked in high ''absolute value'' (high gain or loss) conditions: being highest for large gains in subjects who believed they performed well while being highest for large losses in those who believed they performed poorly. These results suggest that the neural activity preceding goal-directed actions incorporates the absolute value of that action, predicated upon subjective, rather than objective, estimates of one's performance. [ABSTRACT FROM AUTHOR]

Summary: Each action has sensory consequences that need to be distinguished from sensations arising from the environment. This is accomplished by the comparing of internal predictions about these consequences with the actual afference, thereby isolating the afferent component that is self-produced . Because the sensory consequences of actions vary as a result of changes of the effector''s efficacy, internal predictions need to be updated continuously and on a short time scale. Here, we tested the hypothesis that this updating of predictions about the sensory consequences of actions is mediated by the cerebellum, a notion that parallels the cerebellum''s role in motor learning . Patients with cerebellar lesions and their matched controls were equally able to detect experimental modifications of visual feedback about their pointing movements. When such feedback was constantly rotated, both groups instantly attributed the visual feedback to their own actions. However, in interleaved trials without actual feedback, patients did no longer account for this feedback rotation—neither perceptually nor with respect to motor performance. Both deficits can be explained by an impaired updating of internal predictions about the sensory consequences of actions caused by cerebellar pathology. Thus, the cerebellum guarantees both precise performance and veridical perceptual interpretation of actions. [Copyright &y& Elsevier]

Despite smooth pursuit eye movements, we are unaware of resultant retinal image motion. This example of perceptual invariance is achieved by comparing retinal image slip with an internal reference signal predicting the sensory consequences of the eye movement. This prediction can be manipulated experimentally, allowing one to vary the amount of self-induced image motion for which the reference signal compensates and, accordingly, the resulting percept of motion. Here we were able to map regions in CRUS I within the lateral cerebellar hemispheres that exhibited a significant correlation between functional magnetic resonance imaging signal amplitudes and the amount of motion predicted by the reference signal. The fact that these cerebellar regions were found to be functionally coupled with the left parieto-insular cortex and the supplementary eye fields points to these cortical areas as the sites of interaction between predicted and experienced sensory events, ultimately giving rise to the perception of a stable world despite self-induced retinal motion. [ABSTRACT FROM AUTHOR]

Abstract: When our eyes track objects that are moving in a richly structured environment, the retinal image of the stationary visual scene inevitably moves over the retina in a direction opposite to the eye movement. Such self-motion-induced global retinal slip usually provides an ideal stimulus for the optokinetic reflex. This reflex operates to compensate for global image flow. However, during smooth pursuit eye movements it must be shut down so that the reflex does not counteract the voluntary pursuit of moving targets. Here, we asked if retinal information is sufficient for this cancellation of the optokinetic reflex during smooth pursuit eye movements. In a series of experiments, we show that neither the eye movement-induced retinal image motion per se nor the relative motion between the pursuit target and the background are sufficient for suppression of optokinesis. We, therefore, conclude that extra-retinal information about smooth pursuit eye movements is required for the cancellation of the optokinetic reflex. [Copyright &y& Elsevier]

Summary: Psychopathological symptoms in schizophrenia patients suggest that the concept of self might be disturbed in these individuals [1]. Delusions of influence make them feel that someone else is guiding their actions, and certain kinds of their hallucinations seem to be misinterpretations of their own inner voice as an external voice, the common denominator being that self-produced information is perceived as if coming from outside. If this interpretation were correct, we might expect that schizophrenia patients might also attribute the sensory consequences of their own eye movements to the environment rather than to themselves, challenging the percept of a stable world. Indeed, this seems to be the case because we found a clear correlation between the strength of delusions of influence and the ability of schizophrenia patients to cancel out such self-induced retinal information in motion perception. This correlation reflects direct experimental evidence supporting the view that delusions of influence in schizophrenia might be due to a specific deficit in the perceptual compensation of the sensory consequences of one’s own actions [1–6]. [Copyright &y& Elsevier]

When lying inside a MRI scanner and even in the absence of any motion, the static magnetic field of MRI scanners induces a magneto-hydrodynamic stimulation of subjects' vestibular organ (MVS). MVS thereby not only causes a horizontal vestibular nystagmus but also induces a horizontal bias in spatial attention. In this study, we aimed to determine the time course of MVS-induced biases in both VOR and spatial attention inside a 3 T MRI-scanner as well as their respective aftereffects after participants left the scanner. Eye movements and overt spatial attention in a visual search task were assessed in healthy volunteers before, during, and after a one-hour MVS period. All participants exhibited a VOR inside the scanner, which declined over time but never vanished completely. Importantly, there was also an MVS-induced horizontal bias in spatial attention and exploration, which persisted throughout the entire hour within the scanner. Upon exiting the scanner, we observed aftereffects in the opposite direction manifested in both the VOR and in spatial attention, which were statistically no longer detectable after 7 min. Sustained MVS effects on spatial attention have important implications for the design and interpretation of fMRI-studies and for the development of therapeutic interventions counteracting spatial neglect. [ABSTRACT FROM AUTHOR]

Goal-directed hand movements are usually directed straight at the target, e.g. when swatting a fly. Their paths can also become quite complex, when drawing or avoiding obstacles. Studies on movement planning have largely neglected the latter movement type and the question of whether it is the same neural machinery that is planning such complex hand trajectories as well as straight, vector-like movements. Using time-resolved fMRI during delayed response tasks we examined planning activity in human superior parietal lobule (SPL) and dorsal premotor cortex (PMd). We show that the recruitment of both areas in trajectory planning differs significantly: PMd represented both straight and complex hand trajectories while SPL only those that led straight to the target. This suggests that while posterior parietal cortex only provides representations for simple, straight reaches, the complex and computationally demanding reach planning necessarily involves dorsal premotor cortex. Our findings yield new insights into the organization of cerebro-cortical strategies of forming reach trajectory plans. [ABSTRACT FROM AUTHOR]

Axions and axion‐like particles are hypothetical particles predicted in extensions of the standard model and are promising cold dark matter candidates. The Any Light Particle Search (ALPS II) experiment is a light‐shining‐through‐the‐wall experiment that aims to produce these particles from a strong light source and magnetic field and subsequently detect them through a reconversion into photons. With an expected rate ≈1 photon per day, a sensitive detection scheme needs to be employed and characterized. One foreseen detector is based on a transition edge sensor (TES). Here, the machine and deep learning algorithms for the rejection of background events recorded with the TES are investigated. A first application of convolutional neural networks to classify time series data measured with the TES is also presented. [ABSTRACT FROM AUTHOR]

Working memory (WM) is the key process linking perception to action. Several lines of research have, accordingly, highlighted WM's engagement in sensori-motor associations between retrospective stimuli and future behavior. Using human fMRI we investigated whether prior information about the effector used to respond in a WM task would have an impact on the way the same sensory stimulus is maintained in memory despite a behavioral response could not be readily planned. We focused on WM-related activity in posterior parietal cortex during the maintenance of spatial items for a subsequent match-to-sample comparison, which was reported either with a verbal or with a manual response. We expected WM activity to be higher for manual response trials, because of posterior parietal cortex's engagement in both spatial WM and hand movement preparation. Increased fMRI activity for manual response trials in bilateral anterior intraparietal sulcus confirmed our expectations. These results imply that the maintenance of sensory material in WM is optimized for motor context, i.e. for the effector that will be relevant in the upcoming behavioral responses. [ABSTRACT FROM AUTHOR]

Behavioral studies show that motor actions are planned by adapting motor programs to produce desired visual consequences. Does this mean that the brain plans these visual consequences independent of the motor actions required to obtain them? Here we addressed this question by investigating planning-related fMRI activity in human posterior parietal (PPC) and dorsal premotor (PMd) cortex. By manipulating visual movement of a virtual end-effector controlled via button presses we could dissociate motor actions from their sensory outcome. A clear representation of the visual consequences was visible in both PPC and PMd activity during early planning stages. Our findings suggest that in both PPC and PMd action plans are initially represented on the basis of the desired sensory outcomes while later activity shifts towards representing motor programs. [ABSTRACT FROM AUTHOR]

Transition Edge Sensors (TESs) have found widespread application in fundamental studies due to their low background rate, high efficiency, and excellent energy resolution. This makes them suitable candidates for ALPS II, which investigates the existence of new particles (axions and axion-like-particles) which couple very weakly to photons. ALPS II anticipates an extremely low signal rate < 10 - 5 cps (amounting to ∼ 1–2 photons a day). The detection of these low energy (∼ 1 eV, 1064 nm) photons with a high energy resolution is necessary for ALPS II. We show that with our TES setup, we can analyze the TES pulses with different methods such as pulse fitting and Principal Component Analysis (PCA). These achieve (using the standard deviation) an energy resolution ( Δ E / E ) down to ∼ 8 % . The pulse analysis, with a chosen fitting approach, assists also in achieving a very low dark count rate O 10 - 6 cps for 1064 nm photon signal searches in the TES. [ABSTRACT FROM AUTHOR]

A finite axion–nucleon coupling, nearly unavoidable for QCD axions, leads to the production of axions via the thermal excitation and subsequent de-excitation of 57 Fe isotopes in the sun. We revise the solar bound on this flux adopting the up to date emission rate, and investigate the sensitivity of the proposed International Axion Observatory IAXO and its intermediate stage BabyIAXO to detect these axions. We compare different realistic experimental options and discuss the model dependence of the signal. Already BabyIAXO has sensitivity far beyond previous solar axion searches via the nucleon coupling and IAXO can improve on this by more than an order of magnitude. [ABSTRACT FROM AUTHOR]

Summary: Perception and action are governed not only by sensory information but also by prior predictions about sensory events. These sensory predictions allow one to react more rapidly to predictable information in the environment [1] and to perceptually distinguish self-produced and externally produced sensations [2–6]. In order to be accurate, however, all sensory predictions need continuous recalibration to match the changing properties of the environment, the sensorimotor system, or both. Earlier studies showed that the cerebellum is crucial for the recalibration of sensory predictions capturing the sensory consequences of one’s motor behavior [5, 7]. Here we asked whether the cerebellum, a structure intimately linked to plasticity within the motor domain [8–13], also accounts for the recalibration of sensory predictions about external sensory events within the perceptual domain in a nonmotor task. Cerebellar patients and healthy controls were equally able to predict the time of reappearance of a moving target that temporarily disappeared behind an occluder. However, patients were significantly impaired in recalibrating this spatiotemporal prediction to account for an experimentally added delay. This suggests that the cerebellum plays a domain-general role in fine tuning predictive models. [ABSTRACT FROM AUTHOR]

Sensorimotor learning critically depends on error signals. Learning usually tries to minimise these error signals to guarantee optimal performance. Errors can, however, have both internal causes, resulting from one's sensorimotor system, and external causes, resulting from external disturbances. Does learning take into account the perceived cause of error information? Here, we investigated the recalibration of internal predictions about the sensory consequences of one's actions. Since these predictions underlie the distinction of self- and externally produced sensory events, we assumed them to be recalibrated only by prediction errors attributed to internal causes. When subjects were confronted with experimentally induced visual prediction errors about their pointing movements in virtual reality, they recalibrated the predicted visual consequences of their movements. Recalibration was not proportional to the externally generated prediction error, but correlated with the error component which subjects attributed to internal causes. We also revealed adaptation in subjects' motor performance which reflected their recalibrated sensory predictions. Thus, causal attribution of error information is essential for sensorimotor learning. [ABSTRACT FROM AUTHOR]

Abstract: When interacting with the world, we need to distinguish whether sensory information results from external events or from our own actions. The nervous system most likely draws this distinction by comparing the actual sensory input with an internal prediction about the sensory consequences of one’s actions. However, interacting with the world also requires an evaluation of the outcomes of self-action, e.g. in terms of their affective valence. Here we show that subjects’ perceived pointing direction does not only depend on predictive and sensory signals related to the performed action itself, but also on the affective valence of the action outcome: subjects perceived their movements as directed towards positive and away from negative outcomes. Our findings suggest that the non-conceptual perception of the sensory consequences of self-action builds on both sensorimotor information related directly to self-action and a post hoc evaluation of the affective action outcome. [Copyright &y& Elsevier]

Contralateral hemispheric representation of sensory inputs (the right visual hemifield in the left hemisphere and vice versa) is a fundamental feature of primate sensorimotor organization, in particular the visuomotor system. However, many higher-order cognitive functions in humans show an asymmetric hemispheric lateralization-e.g., right brain specialization for spatial processing-necessitating a convergence of information from both hemifields. Electrophysio-logical studies in monkeys and functional imaging in humans have investigated space and action representations at different stages of visuospatial processing, but the transition from contralateral to unified global spatial encoding and the relationship between these encoding schemes and functional lateralization are not fully understood. Moreover, the integration of data across monkeys and humans and elucidation of interspecies homologies is hindered, because divergent findings may reflect actual species differences or arise from discrepancies in techniques and measured signals (electrophysiology vs. imaging). Here, we directly compared spatial cue and memory representations for action planning in monkeys and humans using event-related functional MRI during a working-memory oculomotor task. In monkeys, cue and memory-delay period activity in the frontal, parietal, and temporal regions was strongly contralateral. In putative human functional homologs, the contralaterality was significantly weaker, and the asymmetry between the hemispheres was stronger. These results suggest an inverse relationship between contralaterality and lateralization and elucidate similarities and differences in human and macaque cortical circuits subserving spatial awareness and oculomotor goal-directed actions. [ABSTRACT FROM AUTHOR]

The ALPS II experiment, Any Light Particle Search II at DESY in Hamburg, will look for sub-eV mass new fundamental bosons (e.g., axion-like particles, hidden photons, and other weakly interacting sub-eV particles) in the next years by means of a light-shining-through-wall setup. The ALPS II photosensor is a tungsten transition-edge sensor (W-TES) optimized for 1064 nm photons. This TES, operated at 80 mK, has already allowed single infrared photon detections as well as non-dispersive spectroscopy with very low background rates. The demonstrated quantum efficiency for such TES is up to 95 % (1064 nm) as has been already demonstrated by the US National Institute of Standards and Technology. A back-to-back measurement of the ALPS TES quantum efficiency using a calibrated charge-coupled device camera has lead to a first estimation of 30 %. Improvement methods are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Recent work has demonstrated that the sense of agency is not only determined by efference-copy-based internal predictions and internal comparator mechanisms, but by a large variety of different internal and external cues. The study by Moore and colleagues [Moore, J. W., Wegner, D. M., & Haggard, P. (2009). Modulating the sense of agency with external cues. Conscious and Cognition] aimed to provide further evidence for this view by demonstrating that external agency cues might outweigh or even substitute efferent signals to install a basic registration of self-agency. Although the study contains some critical points that, so we argue, are central to a proper interpretation of the data, it hints at a new perspective on agency: optimal cue integration seems to be the key to a robust sense of agency. We here argue that this framework could allow integrating the findings of Moore and colleagues and other recent agency studies into a comprehensive picture of the sense of agency and its pathological disruptions. [Copyright &y& Elsevier]

Recent observations made with advanced LIGO and advanced Virgo have initiated the era of gravitational-wave astronomy. The number of events detected by these '2nd generation' (2G) ground-based observatories is partially limited by noise arising from temperature-induced position fluctuations of the test mass (TM) mirror surfaces used for probing spacetime dynamics. The design of next-generation gravitational-wave observatories addresses this limitation by using cryogenically cooled test masses; current approaches for continuously removing heat (resulting from absorbed laser light) rely on heat extraction via black-body radiation or conduction through suspension fibres. As a complementing approach for extracting heat during observational runs, we investigate cooling via helium gas impinging on the TM in free molecular flow. We establish a relation between cooling power and corresponding displacement noise, based on analytical models, which we compare to numerical simulations. Applying this theoretical framework with regard to the conceptual design of the Einstein telescope (ET), we find a cooling power of 10 mW at 18 K for a gas pressure that exceeds the ET design strain noise goal by at most a factor of ∼3 in the signal frequency band from 3 to 11 Hz. A cooling power of 100 mW at 18 K corresponds to a gas pressure that exceeds the ET design strain noise goal by at most a factor of ∼11 in the band from 1 to 28 Hz. [ABSTRACT FROM AUTHOR]

Elderly adults may master challenging cognitive demands by additionally recruiting the cross-hemispheric counterparts of otherwise unilaterally engaged brain regions, a strategy that seems to be at odds with the notion of lateralized functions in cerebral cortex. We wondered whether bilateral activation might be a general coping strategy that is independent of age, task content and brain region. While using functional magnetic resonance imaging (fMRI), we pushed young and old subjects to their working memory (WM) capacity limits in verbal, spatial, and object domains. Then, we compared the fMRI signal reflecting WM maintenance between hemispheric counterparts of various task-relevant cerebral regions that are known to exhibit lateralization. Whereas language-related areas kept their lateralized activation pattern independent of age in difficult tasks, we observed bilaterality in dorsolateral and anterior prefrontal cortex across WM domains and age groups. In summary, the additional recruitment of cross-hemispheric counterparts seems to be an age-independent domain-general strategy to master cognitive challenges. This phenomenon is largely confined to prefrontal cortex, which is arguably less specialized and more flexible than other parts of the brain. [ABSTRACT FROM AUTHOR]

The Any Light Particle Search II (ALPS II) experiment is a Light-Shining-through-a-Wall experiment under construction at DESY, Hamburg. Its goal is to probe the existence of Axion Like Particles (ALPs), a possible candidate for dark matter. The expected small rate of reconverted photons requires a sensor capable of measuring low-energetic photons (1.165 eV) with high efficiency and a low dark count rate. A first science run in 2022 will be based on a heterodyne detection scheme. For a second run, a Transition Edge Sensor (TES) system is envisioned as a photon-counting detector. The TES reacts to the change in temperature produced by the absorption of a single photon by operating in the transition between the superconducting and normal conducting phases. Due to its high sensitivity, the TES is susceptible to the influence of electronic noise and background events. In this work, we perform analyses in time and frequency domain and compare these results with simulations to understand the detector's energy resolution. The setup of the TES is presented, along with the proposed design to measure its efficiency and linearity. [ABSTRACT FROM AUTHOR]

Four decades after its prediction, the axion remains the most compelling solution to the strong- CP problem and a well-motivated dark matter candidate, inspiring a host of elegant and ultrasensitive experiments based on axion-photon mixing. This article reviews the experimental situation on several fronts. The microwave cavity experiment is making excellent progress in the search for dark matter axions in the μeV range and may plausibly be extended up to 100 μeV. Within the past several years, however, researchers have realized that axions are pervasive throughout string theories, but with masses that fall naturally in the neV range, for which an NMR-based search is under development. Both searches for axions emitted from the Sun's burning core and purely laboratory experiments based on photon regeneration have recently made great progress, with ambitious projects proposed for the coming decade. Each of these campaigns has pushed the state of the art in technology, enabling large gains in sensitivity and mass reach. Furthermore, each modality has been exploited in order to search for more generalized axion-like particles, which we also discuss in this review. We are hopeful, even optimistic, that the next review of the subject will concern the discovery of the axion, its properties, and its exploitation as a probe of early universe cosmology and structure formation. [ABSTRACT FROM AUTHOR]

Abstract: The ALPS Collaboration runs a “Light Shining through a Wall” (LSW) experiment to search for photon oscillations into “Weakly Interacting Sub-eV Particles” (WISPs) often predicted by extensions of the Standard Model. The experiment is set up around a superconducting HERA dipole magnet at the site of DESY. Due to several upgrades of the experiment we are able to place limits on the probability of photon–WISP–photon conversions of a . These limits result in today''s most stringent laboratory constraints on the existence of low mass axion-like particles, hidden photons and minicharged particles. [Copyright &y& Elsevier]

Abstract: Clinical data indicate that the brain network of speech motor control can be subdivided into at least three functional–neuroanatomical subsystems: (i) planning of movement sequences (premotor ventrolateral–frontal cortex and/or anterior insula), (ii) preparedness for/initiation of upcoming verbal utterances (supplementary motor area, SMA), and (iii) on-line innervation of vocal tract muscles, i.e., motor execution (corticobulbar system, basal ganglia, cerebellum). Using an event-related design, this functional magnetic resonance imaging (fMRI) study sought to further delineate the contribution of SMA to pre-articulatory processes of speech production (preceding the innervation of vocal tract muscles) during an acoustically paced syllable repetition task forewarned by a tone signal. Hemodynamic activation across the whole brain and the time courses of the responses in five regions of interest (ROIs) were computed. First, motor preparation was associated with a widespread bilateral activation pattern, encompassing brainstem structures, SMA, insula, premotor ventrolateral–frontal areas, primary sensorimotor cortex (SMC), basal ganglia, and the superior cerebellum. Second, calculation of the time courses of BOLD (“blood oxygenation level-dependent”) signal changes revealed the warning stimulus to elicit synchronous onset of hemodynamic activation in these areas. However, during 4-s intervals of syllable repetitions SMA and cerebellum showed opposite temporal activation patterns in terms of a shorter (SMA) and longer (cerebellum) latency of the entire BOLD response—as compared to SMC, indicating different pacing mechanisms during the initial and the ongoing phase of the task. Nevertheless, the contribution of SMA was not exclusively restricted to the preparation/initiation of verbal responses since the extension of mesiofrontal activation varied with task duration. [Copyright &y& Elsevier]

The experience of being the initiator of one's own actions seems to be infallible at first glance. Misattributions of agency of one's actions in certain neurological or psychiatric patients reveal, however, that the central mechanisms underlying this experience can go astray. In particular, delusions of influence in schizophrenia might result from deficits in an inferential mechanism that allows distinguishing whether or not a sensory event has been self-produced. This distinction is made by comparing the actual sensory information with the consequences of one's action as predicted on the basis of internal action-related signals such as efference copies. If this internal prediction matches the actual sensory event, an action is registered as self-caused; in case of a mismatch, the difference is interpreted as externally produced. We tested the hypothesis that delusions of influence are based on deficits in this comparator mechanism. In particular, we tested whether patients’ impairments in action attribution tasks are caused by imprecise predictions about the sensory consequences of self-action. Schizophrenia patients and matched controls performed pointing movements in a virtual-reality setup in which the visual consequences of movements could be rotated with respect to the actual movement. Experiment 1 revealed higher thresholds for detecting experimental feedback rotations in the patient group. The size of these thresholds correlated positively with patients’ delusions of influence. Experiment 2 required subjects to estimate their direction of pointing visually in the presence of constantly rotated visual feedback. When compared to controls, patients’ estimates were significantly better adapted to the feedback rotation and exhibited an increased variability. In interleaved trials without visual feedback, i.e. when pointing estimates relied solely on internal action-related signals, this variability was likewise increased and correlated with both delusions of influence and the size of patients’ detection thresholds as assessed in the first experiment. These findings support the notion that delusions of influence are based on imprecise internal predictions about the sensory consequences of one's actions. Moreover, we suggest that such imprecise predictions prompt patients to rely more strongly on (and thus adapt to) external agency cues, in this case vision. Such context-dependent weighted integration of imprecise internal predictions and alternative agency cues might thus reflect the common basis for the various misattributions of agency in schizophrenia patients. [ABSTRACT FROM PUBLISHER]

Abstract: The ALPS Collaboration runs a “light shining through a wall” (LSW) experiment to search for photon oscillations into “weakly interacting sub-eV particles” (WISPs) inside of a superconducting HERA dipole magnet at the site of DESY. In this paper we report on the first successful integration of a large-scale optical resonant cavity to boost the available power for WISP production in this type of experiments. The key elements are a frequency tunable narrow line-width continuous wave laser acting as the primary light source and an electronic feed-back control loop to stabilize the power build-up. We describe and characterize our apparatus and demonstrate the data analysis procedures on the basis of a brief exemplary run. [Copyright &y& Elsevier]