Joachim Hass

SRH University of Applied Sciences · School of Psychology

A prominent finding in psychophysical experiments on time perception is Weber's law, the linear scaling of timing errors with duration. The ability to reproduce this scaling has been taken as a criterion for the validity of neurocomputational models of time perception. However, the origin of Weber's law remains unknown, and currently only a few mod...

The ability to tell time is a crucial requirement for almost everything we do, but the neural mechanisms of time perception are still largely unknown. One way to approach these mechanisms is through computational modeling. This review provides an overview of the most prominent timing models, experimental evidence in their support, and formal ways f...

The prefrontal cortex is centrally involved in a wide range of cognitive functions and their impairment in psychiatric disorders. Yet, the computational principles that govern the dynamics of prefrontal neural networks, and link their physiological, biochemical and anatomical properties to cognitive functions, are not well understood. Computational...

Dynamic causal modeling (DCM) is an analysis technique that has been successfully used to infer about directed connectivity between brain regions based on imaging data such as functional magnetic resonance imaging (fMRI). Most variants of DCM for fMRI rely on a simple bilinear differential equation for neural activation, making it difficult to inte...

Persistent activity, the maintenance of neural activation over short periods of time in cortical networks, is widely thought to underlie the cognitive function of working memory. A large body of modeling studies has reproduced this kind of activity using cell assemblies with strengthened synaptic connections. However, almost all of these studies ha...

The theory of embodied simulation suggests a common neuronal representation for action and perception in mirror neurons (MN) that allows an automatic understanding of another person’s mental state. Multivariate pattern analysis (MVPA) of fMRI data enables a joint investigation of the MN properties cross-modality and action specificity with high spa...

Coordinated movements, speech, and other actions are impossible without precise timing. Computational models of interval timing are expected to provide key insights into the underlying mechanisms of timing, which are currently largely unknown. So far, existing models have only been partially replicating key experimental observations, such as the li...

Coordinated movements, speech, and other actions are impossible without precise timing. Computational models of interval timing are expected to provide key insights into the underlying mechanisms of timing, which are currently largely unknown. So far, existing models have only been partially replicating key experimental observations, such as the li...

Science and humanities divide the world, but also unite it. This attitude is the only one that brings progress and has the goal of creating an understanding of the world. This is reflected in our collaboration for this volume. Each project brings its own particular view of the roles of the concept of “number,” “measurement,” and “pattern” in unders...

At first glance, psychology and physics seem to have nothing in common. However, in both disciplines, sections are dealing with the study of one of the most complex objects in the universe: the human brain. Within psychology, neuropsychologists and neuroscientists “watch the brain at work” by measuring electrical and magnetic signals while particip...

The human mirror neuron system (MNS) can be considered the neural basis of social cognition. Identifying the global network structure of this system can provide significant progress in the field. In this study, we use dynamic causal modeling (DCM) to determine the effective connectivity between central regions of the MNS for the first time during d...

Coordinated movements, speech, and other actions are impossible without precise timing. Computational models of interval timing are expected to provide key insights into the underlying mechanisms of timing, which are currently largely unknown. So far, existing models have only been partially replicating key experimental observations, such as the li...

Background In Neonatal Intensive Care Units (NICUs) premature infants are exposed to various acoustic, environmental and emotional stressors which have a negative impact on their development and the mental health of their parents. Family-centred music therapy bears the potential to positively influence these stressors. The few existing studies indi...

According to the theory of embodied simulation, mirror neurons (MN) in our brain's motor system are the neuronal basis of all social-cognitive processes. The assumption of such a mirroring process in humans could be supported by results showing that within one person the same region is involved in different social cognition tasks. We conducted an f...

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Our ability to infer other individuals’ emotions is central for successful social interactions. Based on the theory of embodied simulation, our mirror neuron system (MNS) provides the essential link between the observed facial configuration of another individual and our inference of that emotion by means of common neuronal activation. However, so f...

Deficits in social cognition have been proposed as a marker of schizophrenia. Growing evidence suggests especially hyperfunctioning of the right posterior superior temporal sulcus (pSTS) in response to neutral social stimuli reflecting the neural correlates of social-cognitive impairments in schizophrenia. We characterized healthy participants acco...

Persistent activity, the maintenance of neural activation over short periods of time in cortical networks, is widely thought to underlie the cognitive function of working memory. A large body of modeling studies has reproduced this kind of activity using cell assemblies with strengthened synaptic connections. However, almost all of these studies ha...

Significance The canonical model of the basal ganglia is based on competing direct (GO) vs. indirect (NO-GO) pathways. However, how is either of the two pathways activated if they receive the same corticostriatal inputs as experimental evidence suggests? Also, in the context of rule-based decisions, how is a specific action selected among competing...

Oscillations are ubiquitous features of brain dynamics that undergo task-related changes in synchrony, power, and frequency. The impact of those changes on target networks is poorly understood. In this work, we used a biophysically detailed model of prefrontal cortex (PFC) to explore the effects of varying the spike rate, synchrony, and waveform of...

Separation of fRPC and fRIN requires a PC population with heterogeneous spike times. (A) Time-averaged firing rate profiles of PC (blue) and IN (red) cells in a minimal PC/IN network with one PC and one IN given high synchrony, square wave input. The IN can spike only when the PC spikes which causes their firing rates to peak in response to the sam...

Comparison of types of resonance in the single PC and PC/IN networks. (A) After removing background noise to allow for subthreshold fluctuations, subthreshold resonance in the voltage fluctuation was observed at 2 Hz in a single principal cell (PC) driven by a weak sinusoidal drive (rinp = .1 kHz). Example voltage traces are shown in response to as...

Time-averaged firing rate resonance in the PFC network with 100 PCs and 37 INs. (A) Firing rate profile for PC (blue) and IN (red) populations in a PFC network with 100 PCs and 37 INs. All parameters of the model were kept fixed relative to the control model except the number of cells per population was increased. Note that the resonant frequencies...

Suppression of response to asynchronous activity does not occur when the natural frequency equals the population frequency of the target. (A) Diagram showing a target PC population, PCT, driven by medium-synchrony oscillatory input at the 28 Hz fpop-resonant frequency in competition with a distractor PC population, PCD, driven by a higher-rate asyn...

Example iFR power spectra used for the determination of population frequency. (A) Response to 8 Hz sinusoidal drive. (i) Nested oscillations in the PC iFR. (ii) Power spectrum with peaks at both the external driving frequency and frequency of internally-generated, nested oscillations. Low-synchrony square wave inputs can also produce nested oscilla...

Input frequency-dependent output response profiles in integrate-and-fire networks. Qualitative features of the PFC network model were reproduced in a simpler PC/IN network model with leaky integrate-and-fire (LIF) neurons. (top) Firing rate profile for PC (blue) and IN (red) populations. (bottom) Population frequency profile for PC and IN populatio...

Suppression of response to asynchronous activity occurs within one cycle of the target oscillating more quickly. (A) Diagram showing a target PC population, PCT, driven by an asynchronous input during period T1 then a medium-synchrony oscillatory input at the 28 Hz fpop-resonant frequency during period T2 in competition with a distractor PC populat...

Relationship between resonance with fixed-mean square waves and responses to fixed-amplitude square waves. (A) Response to fixed-amplitude square wave with pulse amplitude fixed to rp = 4 kHz for all driving frequencies. (i) Firing rate (FR) profile for medium-synchrony square waves. Given fixed pulse amplitude, mean input strength increases with i...

Oscillations are ubiquitous features of brain dynamics that undergo task-related changes in synchrony, power, and frequency. The impact of those changes on target networks is poorly understood. In this work, we used a biophysically detailed model of prefrontal cortex (PFC) to explore the effects of varying the spike rate, synchrony, and waveform of...

Classical accounts of biased competition (BC) require an input bias to resolve the competition between neuronal ensembles driving downstream processing. However, flexible and reliable selection of behaviorally-relevant ensembles can occur with unbiased stimulation: striatal D1 and D2 spiny projecting neurons (SPNs) receive balanced cortical input,...

Die Wissenschaft spaltet die Welt, aber einigt sie auch. Diese Einstellung ist die einzige, die Fortschritt bringt und das Ziel hat, ein Verständnis der Welt zu schaffen. Das spiegelt sich auch in unserer Zusammenarbeit für diesen Band wider. Jedes Projekt bringt seine eigene spezielle Sicht auf die Rollen von „Zahl“, „Messung“ und „Muster“ beim Ve...

Psychologie und Physik scheinen auf den ersten Blick nichts miteinander zu tun zu haben. Doch in beiden Fachrichtungen gibt es Teilgebiete, die sich mit der Erforschung eines der komplexesten Objekte des Universums beschäftigen: dem menschlichen Gehirn. Innerhalb der Psychologie sind es Neuropsychologen, die durch die Messung von elektrischen und m...

Mathematical modeling is a useful tool for understanding the neurodynamical and computational mechanisms of cognitive abilities like time perception, and for linking neurophysiology to psychology. In this chapter, we discuss several biophysical models of time perception and how they can be tested against experimental evidence. After a brief overvie...

Correlations among neurons are supposed to play an important role in neural computation and information coding in the nervous system. Empirically, functional interactions between neurons are most commonly assessed by cross-correlation functions. Recent studies have suggested that pairwise correlations may indeed be sufficient to capture most of the...

For large-scale network simulations, it is often desirable to have computationally tractable, yet in a defined sense still physiologically valid neuron models. In particular, these models should be able to reproduce physiological measurements, ideally in a predictive sense, and under different input regimes in which neurons may operate in vivo. Her...

Temporal information is often contained in multi-sensory stimuli, but it is currently unknown how the brain combines e.g. visual and auditory cues into a coherent percept of time. The existing studies of cross-modal time perception mainly support the "modality appropriateness hypothesis", i.e. the domination of auditory temporal cues over visual on...

Setup of the experiment. Participants stood in front of a screen wearing headphones. They moved the end effector of a robotic manipulandum in order to move a proxy on the screen. (EPS)

Sketch of the screen contents for visual feedback during the motor task. A blue sphere (target) moves along an elliptic trajectory at a prescribed speed. A red sphere (proxy) can be moved with a robotic manipulandum. Two ellipses surround the trajectory of the blue sphere to mark an area that should not be left by the red sphere. Numbers depict the...

DL (in ms) for each individual condition and experiment. Each cell contains the average over all participants, and standard deviation in brackets. In Experiment 3, the Time and Time-Motion condition (abbreviated TM) are reported separately. (PDF)

PSE (in ms) for each individual condition and experiment. Each cell contains the average over all participants, and standard deviation in brackets. In Experiment 3, the Time and Time-Motion condition (abbreviated TM) are reported separately. (PDF)

PSE (in ms) for each experiment averaged for the Time, Time-Motion (abbreviated TM), Straights and Curves condition. Each cell contains the average over all participants, and standard deviation in brackets. In Experiment 3, the Time and Time-Motion condition are reported separately. (PDF)

DL (in ms) for each experiment averaged for the Time, Time-Motion (abbreviated TM), Straights and Curves condition. Each cell contains the average over all participants, and standard deviation in brackets. In Experiment 3, the Time and Time-Motion condition are reported separately. (PDF)

Velocity for each experiment averaged for the Straights and Curves condition of the Motion and the Time-Motion (abbreviated TM) condition, respectively, measured in units of screen units per second (one screen unit equals 30 cm on the computer screen). Each cell contains the average over all participants, and standard deviation in brackets. (PDF)

Curvature for each experiment averaged for the Straights and Curves condition of the Motion and the Time-Motion (abbreviated TM) condition, respectively, measured in units of inverse screen units (one screen unit equals 30 cm on the computer screen). Each cell contains the average over all participants, and standard deviation in brackets. (PDF)

Information about data analysis, the training phase in Experiment 4, data on individual conditions, Experiment 1b, and correlations between time and motion data. (PDF)

Combining experiments and modeling, we study how the discrimination of time intervals depends both on the interval duration and on contextual stimuli. Participants haul to judge the temporal regularity of a sequence of standard intervals that contained a deviant interval. We find that the performance to detect the deviant increases with the number...

Humans can estimate the duration of intervals of time, and psychophysical experiments show that these estimations are subject to timing errors. According to standard theories of timing, these errors increase linearly with the interval to be estimated (Weber's law), and both at longer and shorter intervals, deviations from linearity are reported. Th...

itor> Meeting abstracts - A single PDF containing all abstracts in this Supplement is available here http://www. biomedcentral.co m/content/pdf/14 71-2202-8-S2-in fo.pdf

This paper reports how and to what extent the mass distribution of a passive dynamic walker can be tuned to maximize walking speed and stability. An exploration of the complete parameter space of a bipedal walker is performed by numerical optimization, and optimal manifolds are found in terms of speed, the form of which can be ex-plained by a physi...

This work is concerned with passive dynamic walking on downhill slopes where gaits are at best of fragile stability. A hybrid Darwin-Boltzmann optimization technique is used to search for regions in parameter space where unstable gait cycles are likely and can subsequently be improved by a Newton method. Periodic gaits are present for parameters al...