Biology subjects

Sterzer, P.

Publications and source records attributed to Sterzer, P..

10 recordsLinked to original sources

bioRxiv2026

Baseline activity of V1 interneurons connects pupil-linked arousal to engaged behavioral state

AO_SCPLOWBSTRACTC_SCPLOWHumans and rodents alternate between discrete, persistent behavioral states during perceptual decision-making. For example, trials can be clustered into states of engaged, disengaged, and biased decision-making strategies. In mice, the probability of being in an engaged state exhibits an inverted-U relationship with baseline pupil-linked arousal, consistent with the Yerkes-Dodson Law. We replicated this relationship in mice (N=11; audio-visual change detection task) and showed that it generalizes to humans (N=69; auditory detection task). We then examined its neural basis, using simultaneous pupillometry and electrophysiological recordings in mouse V1. A nonlinear mediation model revealed that baseline activity of putative fast-spiking interneurons, but not putative pyramidal neurons, made a significant statistical contribution to the inverted-U shaped relationship between pupil-linked arousal and engaged-state probability. These findings are consistent with the idea that arousal may shape behavioral states by modulating baseline inhibitory activity within a primary sensory region.

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bioRxiv2026

History-dependent Biases in Perceptual Decisions Depend on NMDA Receptors

Perceptual decisions are governed not only by current sensory input but also by the history of previous stimuli, choices, or outcomes. Such history-dependent biases evolve across multiple timescales ranging from seconds to minutes. Synaptic plasticity is one possible mechanism mediating such effects. The by N-methyl-aspartate (NMDA) glutamate receptor is critical for synaptic plasticity, and indirect evidence points to its role in the generation of history-dependent biases. Here, we pharmacologically blocked NMDA receptors in healthy human participants performing a two-alternative visual decision-making task. Participants choices were biased by the accumulation of fluctuating sensory evidence within each trial as well as the accumulation of across-trial sequences of stimuli, which enabled them to adapt to changing stimulus statistics across blocks. NMDA receptor blockade reduced the task-adaptive across trials, history-dependent biases. In contrast, enhancing GABA-A receptor activity in the same participants increased the transiency of the within-trial evidence accumulation dynamics. Our findings provide direct evidence for the importance of NMDA receptor function in history-dependent biases in the human brain.

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bioRxiv2024

Ischemic lesions to inferior frontal cortex alter the dynamics of conscious visual perception

Whether the prefrontal cortex is part of the neural correlates of conscious visual perception has been subject to longstanding debate. Recent work, using functional magnetic resonance imaging (fMRI) and repetitive transcranial magnetic stimulation (rTMS) to induce virtual lesions, has illustrated a key role of the right inferior frontal cortex (IFC) in the detection and resolution of perceptual ambiguities. Here, we sought to validate an active role of the IFC in conscious perception by evaluating how loss-of-function in patients with ischemic stroke in this region influences processing of ambiguous visual information. To this end, twenty-three patients (11 female, mean age 70.65 {+/-} 1.2 years) with chronic (>6 months), right-hemispheric ischemic stroke lesions within the MCA-territory (9 patients with IFC lesions, 14 without) performed a bistable perception task, having to report the perceived direction of rotation of an ambiguous random-dot-kinematogram (RDK). As hypothesized, patients with IFC lesions showed significantly fewer perceptual changes compared to patients without IFC lesions (IFC 44.9 {+/-} 46.3 s, non-IFC 28.2 {+/-} 37.1 s, T(182.9) =3.1, p = 2.2 x 10-3). Importantly, this effect remained significant when controlling for age, sex, stroke severity and lesion volume (T(5.97) = -2.9, p =0.026). Our results support the notion that the IFC is crucial for resolving perceptual ambiguities, suggesting an active role of frontal cortex in shaping conscious visual experience.

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bioRxiv2024

Anterior insular activity signals perceptual conflicts induced by temporal and spatial context

The signals registered by our senses are inherently ambiguous. Subjective experience, by contrast, is informative: it portrays one interpretation of the sensory environment at a time while discarding competing alternatives. This is exemplified by bistable perception, where ambiguous sensory information induces prolonged intervals of alternating unambiguous perceptual states. According to predictive-processing accounts of bistable perception, perceptual experiences in the recent past constitute a predictive context that stabilizes perception, while sensory information that is in conflict with this predictive context evokes prediction errors. These prediction errors are thought to drive spontaneous perceptual switches. We asked whether this mechanism generalizes to conflicts between other forms of predictive context and sensory information. To this aim, we investigated the neural correlates of perceptual conflicts with temporal and spatial context during bistable perception using functional magnetic resonance imaging (fMRI). Twenty-six healthy participants viewed serial presentations of ambiguous structure-from-motion stimuli either in isolation (conflict with temporal context) or embedded in a similar but unambiguous surround stimulus (conflict with spatial context). The neural correlates of conflicts with temporal and spatial context overlapped in the anterior insula bilaterally. Model-based analyses similarly yielded common prediction error signals in the anterior insula bilaterally, right inferior frontal gyrus and right inferior parietal lobe. Together, these findings point to a generic role of these frontoparietal regions in detecting perceptual conflict and thus in the construction of unambiguous perceptual experiences.

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bioRxiv2024

N-Methyl-D-aspartate receptor hypofunction causes recurrent and transient failures of perceptual inference

1Perception alternates between an external mode, driven by sensory inputs, and an internal mode, shaped by prior knowledge. We found that the external mode is more prevalent during pharmacologically induced N-Methyl-D-aspartate receptor (NMDAR) hypofunction and in schizophrenia. This NMDAR-dependent increase in external mode suggests that psychotic experiences are caused by recurring dissociations of perception from prior knowledge about the world.

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bioRxiv2021

Humans and mice fluctuate between external and internal modes of sensory processing

2Perception is known to cycle through periods of enhanced and reduced sensitivity to external information. Here, we asked whether such infra-slow fluctuations arise as a noise-related epiphenomenon of limited processing capacity or, alternatively, represent a structured mech{-}anism of perceptual inference. Using two large-scale datasets, we found that humans and mice waver between alternating intervals of externally- and internally-oriented modes of sensory analysis. During external mode, perception aligned more closely with the external sensory information, whereas internal mode was characterized by enhanced biases toward perceptual history. Computational modeling indicated that dynamic changes in mode are enabled by two interlinked factors: (i), the integration of subsequent inputs over time and, (ii), infra-slow anti-phase oscillations in the perceptual impact of external sensory information versus internal predictions that are provided by perceptual history. Simulated data suggested that between-mode fluctuations may benefit perception by generating unambiguous error signals that enable robust learning and metacognition in volatile environments. 3 One sentence summaryHumans and mice fluctuate between external and internal modes of sensory processing.

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bioRxiv2020

Non-stimulated regions in early visual cortex encode the contents of conscious visual perception

Predictions shape our perception. The theory of predictive processing poses that our brains make sense of incoming sensory input by generating predictions, which are sent back from higher to lower levels of the processing hierarchy. These predictions are based on our internal model of the world and enable inferences about the hidden causes of the sensory input data. It has been proposed that conscious perception corresponds to the currently most probable internal model of the world. Accordingly, predictions influencing conscious perception should be fed back from higher to lower levels of the processing hierarchy. Here, we used functional magnetic resonance imaging (fMRI) and multivoxel pattern analysis to show that non-stimulated regions of early visual areas contain information about the conscious perception of an ambiguous visual stimulus. These results indicate that early sensory cortices in the human brain receive predictive feedback signals that reflect the current contents of conscious perception.

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bioRxiv2020

Evidence for an Active Role of Inferior Frontal Cortex in Conscious Experience

2In the search for the neural correlates of consciousness, it has remained controversial whether prefrontal cortex determines what is consciously experienced or, alternatively, serves only complementary functions such as introspection or action. Here, we provide converging evidence from computational modeling and two functional magnetic resonance imaging experiments for a key role of inferior frontal cortex in detecting perceptual conflicts that emerge from ambiguous sensory information. Crucially, the detection of perceptual conflicts by prefrontal cortex turned out to be critical in the process of transforming ambiguous sensory information into unambiguous conscious experiences: In a third experiment, disruption of neural activity in inferior frontal cortex through transcranial magnetic stimulation slowed down the updating of conscious experience that occurs in response to perceptual conflicts. These findings show that inferior frontal cortex actively contributes to the resolution of perceptual ambiguities. Prefrontal cortex is thus causally involved in determining the contents of conscious experience. 3 One-sentence SummaryInferior frontal cortex detects and resolves perceptual conflict during bistable perception.

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bioRxiv2018

Overly strong priors for socially meaningful visual signals in psychosis proneness

Predictive coding accounts of psychosis state that an overweighing of high-level priors relative to sensory information may lead to the misperception of meaningful signals underlying the experience of auditory hallucinations and delusions. However, it is currently unclear whether the hypothesized overweighing of priors (1) represents a pervasive alteration that also affects the visual modality, and, (2) takes already effect at early automatic processing stages.\n\nHere, we addressed these questions by studying visual perception of socially meaningful stimuli in healthy individuals with varying degrees of psychosis proneness (n=39). In a first task, we quantified participants prior for detecting faces in visual noise. In a second task, we measured participants prior for detecting direct gaze stimuli that were rendered invisible by continuous flash suppression. We found that the prior for detecting faces in noise correlated with hallucination proneness (rho=0.50, p=0.001) as well as delusion proneness (rho=0.44, p=0.005). Similarly, the prior for detecting invisible direct gaze was significantly associated with hallucination proneness (rho = 0.42, p = 0.010) and trend-wise with delusion proneness (rho = 0.29, p = 0.087). Our results provide evidence for the idea that overly strong high-level priors for automatically detecting socially meaningful stimuli might constitute a generic processing alteration in psychosis.

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bioRxiv2017

A Confidence-Based Reinforcement Learning Model For Perceptual Learning

It is well established that learning can occur without external feedback, yet normative reinforcement learning theories have difficulties explaining such instances of learning. Recently, we reported on a confidence-based reinforcement learn-ing model for the model case of perceptual learning (Guggenmos, Wilbertz, Hebart, & Sterzer, 2016), according to which the brain capitalizes on internal monitoring processes when no external feedback is available. In the model, internal confidence prediction errors - the difference between current confidence and expected confidence - serve as teaching signals to guide learning. In the present paper, we explore an extension to this idea. The main idea is that the neural information processing pathways activated for a given sensory stimulus are subject to fluctuations, where some pathway configurations lead to higher confidence than others. Confidence prediction errors strengthen pathway configurations for which fluctuations lead to above-average confidence and weaken those that are associated with below-average con-fidence. We show through simulation that the model is capable of self-reinforced perceptual learning and can benefit from exploratory network fluctuations. In addition, by simulating different model parameters, we show that the ideal confidence-based learner should (i) exhibit high degrees of network fluctuation in the initial phase of learning, but re-duced fluctuations as learning progresses, (ii) have a high learning rate for network updates for immediate performance gains, but a low learning rate for long-term maximum performance, and (iii) be neither too under-nor too overconfident. In sum, we present a model in which confidence prediction errors strengthen favorable network fluctuations and enable learning in the absence of external feedback. The model can be readily applied to data of real-world perceptual tasks in which observers provided both choice and confidence reports.

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