@misc{Glasauer, author = {Glasauer, Stefan}, title = {Sequential Bayesian updating as a model for human perception}, series = {Progress in Brain Research}, volume = {249}, journal = {Progress in Brain Research}, issn = {1875-7855}, doi = {10.1016/bs.pbr.2019.04.025}, pages = {3 -- 18}, abstract = {Sequential Bayesian updating has been proposed as model for explaining various systematic biases in human perception, such as the central tendency, range effects, and serial dependence. The present chapter introduces to the principal ideas behind Bayesian updating for the random-change model introduced previously and shows how to implement sequential updating using the exact method via probability distributions, the Kalman filter for Gaussian distributions, and a particle filter for approximate sequential updating. Finally, it is demonstrated how to couple perception to action by selecting an appropriate action based on the posterior distribution that results from sequential updating.}, language = {en} } @misc{SalmasiStemmlerGlasaueretal., author = {Salmasi, Mehrdad and Stemmler, Martin and Glasauer, Stefan and Loebel, Alex}, title = {Synaptic Information Transmission in a Two-State Model of Short-Term Facilitation}, series = {Entropy}, volume = {21}, journal = {Entropy}, number = {8}, issn = {1099-4300}, doi = {10.3390/e21080756}, pages = {13}, abstract = {Action potentials (spikes) can trigger the release of a neurotransmitter at chemical synapses between neurons. Such release is uncertain, as it occurs only with a certain probability. Moreover, synaptic release can occur independently of an action potential (asynchronous release) and depends on the history of synaptic activity. We focus here on short-term synaptic facilitation, in which a sequence of action potentials can temporarily increase the release probability of the synapse. In contrast to the phenomenon of short-term depression, quantifying the information transmission in facilitating synapses remains to be done. We find rigorous lower and upper bounds for the rate of information transmission in a model of synaptic facilitation. We treat the synapse as a two-state binary asymmetric channel, in which the arrival of an action potential shifts the synapse to a facilitated state, while in the absence of a spike, the synapse returns to its baseline state. The information bounds are functions of both the asynchronous and synchronous release parameters. If synchronous release facilitates more than asynchronous release, the mutual information rate increases. In contrast, short-term facilitation degrades information transmission when the synchronous release probability is intrinsically high. As synaptic release is energetically expensive, we exploit the information bounds to determine the energy-information trade-off in facilitating synapses. We show that unlike information rate, the energy-normalized information rate is robust with respect to variations in the strength of facilitation.}, language = {en} } @misc{GlasauerDieterichBrandt, author = {Glasauer, Stefan and Dieterich, Marianne and Brandt, Thomas}, title = {Computational neurology of gravity perception involving semicircular canal dysfunction in unilateral vestibular lesions}, series = {Progress in Brain Research}, volume = {248}, journal = {Progress in Brain Research}, issn = {1875-7855}, doi = {10.1016/bs.pbr.2019.04.010}, pages = {303 -- 317}, abstract = {Unilateral peripheral vestibular lesions not only lead to vertigo, nystagmus and imbalance, but also to a bias in the perception of verticality, which can be measured as tilt of the subjective visual vertical (SVV). Previously, this tilt has been assumed to be caused by a residual otolith bias, for example, because unequal numbers of active haircells on both sides of the utricular striola might result in an imbalance of the firing rates of central otolith neurons. Here we propose that a tilt of the subjective visual vertical might as well be caused by a vertical semicircular canal bias in the roll axis after unilateral peripheral lesions. The canal bias, acting similar to angular velocity stimuli, influences the SVV via the central gravity estimator, which under normal circumstances resolves a perceptual tilt-translation ambiguity. To illustrate our hypothesis, we compare model predictions to data on SVV measurements in patients with unilateral vestibular lesions while being tilted or being rotated eccentrically. We further embed the model of peripheral processing in a neural network that implements the idiotropic bias and represents the direction of gravity as population code in a three dimensional spherical topography.}, language = {en} } @misc{LehnenSchroederHenningsenetal., author = {Lehnen, Nadine and Schr{\"o}der, Lena and Henningsen, Peter and Glasauer, Stefan and Ramaioli, Cecilia}, title = {Deficient head motor control in functional dizziness: Experimental evidence of central sensory-motor dysfunction in persistent physical symptoms}, series = {Progress in Brain Research}, volume = {249}, journal = {Progress in Brain Research}, issn = {1875-7855}, doi = {10.1016/bs.pbr.2019.02.006}, pages = {385 -- 400}, abstract = {Understanding the mechanisms of symptoms that are insufficiently explained by organic dysfunction remains challenging. Recently, it has been proposed that such "functional symptoms" are based on erroneous sensory processing in the central nervous system (CNS), with internal expectations dominating sensory inputs. In a pilot study, we used a head motor control set-up to assess the interplay between sensory input and expectation on the example of patients with functional dizziness. Eight patients and 11 age-matched healthy controls performed large active eye-head gaze shifts towards visual targets in the natural situation and with the head moment of inertia 3.3-fold increased. The latter induces head oscillations and the expected sensory outcome of the movement, estimated in the CNS, does not match the actual sensory input. Head oscillations were assessed in patients and in healthy subjects and compared to prior results from patients with organic disease (vestibular loss and cerebellar ataxia). Head oscillations in patients with functional dizziness were different from those of healthy subjects (F(1,17) = 27.26, P < 0.001, partial η2 = 0.62), and similar to those of patients with cerebellar ataxia, and with vestibular loss (F(2,19) = 0.56, P = 0.58). Even in the natural, unweighted, condition, head oscillations were higher in functional dizziness patients than in healthy subjects (P = 0.001). Since an extensive work-up failed to demonstrate any explanatory peripheral vestibular, motor, or cerebellar organic dysfunction, these motor control deficits are a first indication of erroneous interplay between expectations and sensory input in the CNS that could account for persistent physical symptoms.}, language = {en} } @misc{DietrichHeidgerSchnieppetal., author = {Dietrich, Haike and Heidger, F. and Schniepp, Roman and MacNeilage, Paul R. and Glasauer, Stefan and W{\"u}hr, Max}, title = {Head motion predictability explains activity-dependent suppression of vestibular balance control}, series = {Scientific Reports}, volume = {10}, journal = {Scientific Reports}, issn = {2045-2322}, doi = {10.1038/s41598-019-57400-z}, abstract = {Vestibular balance control is dynamically weighted during locomotion. this might result from a selective suppression of vestibular inputs in favor of a feed-forward balance regulation based on locomotor efference copies. The feasibility of such a feed-forward mechanism should however critically depend on the predictability of head movements (HMP) during locomotion. To test this, we studied in 10 healthy subjects the differential impact of a stochastic vestibular stimulation (SVS) on body sway (center-of-pressure, COP) during standing and walking at different speeds and compared it to activity-dependent changes in HMp. SVS-cop coupling was determined by correlation analysis in frequency and time domains. HMP was quantified as the proportion of head motion variance that can be explained by the average head trajectory across the locomotor cycle. SVS-COP coupling decreased from standing to walking and further dropped with faster locomotion. Correspondingly, HMP increased with faster locomotion. Furthermore, SVS-COP coupling depended on the gait-cycle-phase with peaks corresponding to periods of least HMP. These findings support the assumption that during stereotyped human self-motion, locomotor efference copies selectively replace vestibular cues, similar to what was previously observed in animal models.}, language = {en} } @misc{SalmasiGlasauerStemmler, author = {Salmasi, Mehrdad and Glasauer, Stefan and Stemmler, Martin}, title = {Short-term facilitation and neurotransmitter spillover counteract each other in neuronal information transmission}, series = {28th Annual Computational Neuroscience Meeting: CNS*2019}, journal = {28th Annual Computational Neuroscience Meeting: CNS*2019}, issn = {1471-2202}, doi = {10.1186/s12868-019-0538-0}, pages = {155 -- 156}, language = {en} } @misc{Glasauer, author = {Glasauer, Stefan}, title = {Magnitude Estimation}, abstract = {Data from the publication Petzschner FH, Glasauer S (2011) Iterative Bayesian Estimation as an Explanation for Range and Regression Effects: A Study on Human Path Integration. J Neurosci 31(47):17220 -17229. DOI:10.1523/JNEUROSCI.2028-11.2011 Data is stored in two Matlab files. AE_all.mat contains the raw angular estimation data, DE_all.mat the raw distance estimation data for all participants. Each structure in the cell array Data is for one participant and contains pdata (produced distance or angle, that's the stimulus) and rdata (re-produced distance or angle, the response). There are 3x180 values, first dimension are the three ranges used, so Data{1}.pdata(1,:) contains the stimuli for participant 1 and the short range in the angular estimation experiment (given you loaded AE_all.mat).}, language = {en} } @misc{KutzKolbGlasaueretal., author = {Kutz, Dieter F. and Kolb, Florian P. and Glasauer, Stefan and Straka, Hans}, title = {Somatosensory Influence on Platform-Induced Translational Vestibulo-Ocular Reflex in Vertical Direction in Humans}, series = {Frontiers in Neurology}, volume = {11}, journal = {Frontiers in Neurology}, issn = {1664-2295}, doi = {10.3389/fneur.2020.00332}, pages = {1 -- 10}, abstract = {The vestibulo-ocular reflex (VOR) consists of two components, the rotational VOR (rVOR) elicited by semicircular canal signals and the translational VOR (tVOR) elicited by otolith signals. Given the relevant role of the vertical tVOR in human walking, this study aimed at measuring the time delay of eye movements in relation to whole-body vertical translations in natural standing position. Twenty (13 females and 7 males) healthy, young subjects (mean 25 years) stood upright on a motor-driven platform and were exposed to sinusoidal movements while fixating a LED, positioned at a distance of 50 cm in front of the eyes. The platform motion induced a vertical translation of 2.6 cm that provoked counteracting eye movements similar to self-paced walking. The time differences between platform and eye movements indicated that the subject's timing of the extraocular motor reaction depended on stimulus frequency and number of repetitions. At low stimulus frequencies (<0.8 Hz) and small numbers of repetitions (<3), eye movements were phase advanced or in synchrony with platform movements. At higher stimulus frequencies or continuous stimulation, eye movements were phase lagged by ~40 ms. Interestingly, the timing of eye movements depended on the initial platform inclination. Starting with both feet in dorsiflexion, eye movements preceded platform movements by 137 ms, whereas starting with both feet in plantar flexion eye movement precession was only 19 ms. This suggests a remarkable influence of foot proprioceptive signals on the timing of eye movements, indicating that the dynamics of the vertical tVOR is controlled by somatosensory signals.}, language = {en} } @misc{GlasauerLehnenRadziejetal., author = {Glasauer, Stefan and Lehnen, Nadine and Radziej, Katharina and Weigel, Angelika and K{\"a}nel, Roland von and Pitron, Victor and Van den Bergh, Omer and L{\"o}we, Bernd and Lehmann, Marco and Henningsen, Peter}, title = {Complementing conceptual models of persistent somatic symptoms with mathematical formalization}, series = {Psychosomatic Medicine}, journal = {Psychosomatic Medicine}, issn = {1534-7796}, doi = {10.1097/PSY.0000000000000801}, language = {en} } @misc{KostorzFlanaginGlasauer, author = {Kostorz, Kathrin and Flanagin, Virginia and Glasauer, Stefan}, title = {Synchronization between instructor and observer when learning a complex bimanual skill}, series = {Neuroimage}, journal = {Neuroimage}, issn = {1053-8119}, doi = {10.1016/j.neuroimage.2020.116659}, pages = {20}, abstract = {While learning from an instructor by watching a 'how-to' video has become common practice, we know sur- prisingly little about the relation between brain activities in instructor and observers. In this fMRI study we investigated the temporal synchronization between instructor and observers using intersubject correlation in the naturalistic setting of learning to fold origami. Brain activity of the blindfolded instructor during action pro- duction was compared to the observers while they viewed the instructor's video-taped actions. We demonstrate for the first time that the BOLD activity in the instructor's and observer's brain are synchronized while observing and learning a manual complex task with the goal of reproducing it. We can rule out that this synchrony originates from visual feedback. Observers exhibiting higher synchrony with the instructor in the ventral premotor cortex, while viewing the video for the first time, were more successful in reproducing the origami afterwards. Furthermore, changes in instructor-observer synchrony across observational learning sessions occur in cerebellar areas, as well as differences in instructor-observer synchrony between learning and the counting folds, our non- learning control. Not only known cerebellar motor production areas show synchrony, shedding new light on the involvement of the cerebellum in action observation and learning.}, language = {en} }