Biology subjects

Noesselt, T.

Publications and source records attributed to Noesselt, T..

11 recordsLinked to original sources

bioRxiv2026

The neural signature of simple overlearned temporal expectations resembles episodic retrieval

Temporal expectations are crucial for adaptive responding to predictable events. Most previous imaging studies have focused on the neural underpinnings of unexpectedness rather than expectedness, without considering that neural responses related to temporal expectations may be confounded by parallel learning processes. To identify the neural basis of overlearned expectancy with fMRI, we employed a multi-day detection paradigm with auditory cues preceding visual targets at likely and unlikely time points. After training left inferior parietal cortex was engaged in processing overlearned temporal expectations together with retrosplenial and prefrontal cortex. Remarkably, compared with untrained controls, we observed inverted brain responses as a function of stimulus likelihood and training status. Finally, the brain regions coding overlearned expectancy had previously been implicated in episodic retrieval and simulation (based on Neurosynth association tests), suggesting that frequently used temporal expectations may, over time, utilize episodic memory routines to simulate likely future events and thus guide behavior.

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bioRxiv2024

Neural networks representing temporal expectation in mice

The ability to attend to specific moments in time is crucial for survival across species facilitating perception and motor performance by leveraging prior temporal knowledge for predictive processing. Despite its importance, the neural mechanisms underlying the utilization of macro-scale and meso-scale neural resources during temporal processing and their relationship to behavioural strategies and motor responses remain largely unexplored. To investigate the capacity for predictive temporal structure of multisensory stimuli to optimize motor behaviour, we established a behavioural paradigm, in which mice were trained to an auditory-cue and visual-target presented at expected or unexpected temporal delays. Using a combination of stimulus-evoked and resting-state functional magnetic resonance imaging, we examined task-related evoked activity in brain-wide networks and found that that the formation of temporal expectations relying on accumulated sensory information and combined multisensory input involves plasticity across large macro-scale cortical networks comprised of primary sensory systems, sensory association areas including posterior parietal cortex, retrosplenial cortex, prefrontal top-down executive control centres of the brain, as well as hippocampal networks. Additionally, employing in vivo two-photon calcium imaging, we explored local single-cell dynamics within the posterior parietal cortex during this task and found that temporal expectation could be decoded directly from neuronal activity within this brain region. Overall, our study provides insights into the neural correlates underlying the formation of multisensory temporal expectations in the mouse brain and highlights the recruitment of neural resources across temporally-driven statistical learning processes.

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bioRxiv2023

Contextual modulation of primary visual cortex by temporal predictability during motion extrapolation

Predicting future events is a fundamental cognitive ability which often depends on the volatility of the environment. Previous studies on apparent motion reported that when the brain is confronted with low levels of predictability, activity in low-level sensory areas is increased, including primary visual cortex. However, other studies on temporal predictability reported opposite effects potentially due to the influence of attention. It remains unclear, however, how temporal predictability modulates brain responses in a more ecologically valid real motion paradigm. Our study investigated whether motion extrapolation in high and low predictable contexts would differently modulate fMRI-responses in subject-specific primary visual cortex during visible and partially occluded stimulation. To this end, participants performed a modified version of the interception paradigm in visible and occluded phases, in which they observed a stimulus moving horizontally, then vertically at two different velocities. They were instructed to press when and where the stimulus would reach a given point-of-contact. In high predictable context, the velocity was identical during horizontal and vertical (occluded) movement; whereas, in low predictable context, the velocity could change during the vertical trajectory. MVPA results revealed accuracies above chance for all classification analyses carried out with low and highly predictable context data. Moreover, trial-history analysis showed that a change in trial type (constant velocity after change in velocity and vice versa) increased BOLD-responses in V1. This pattern of results suggests motion extrapolation can enhance activity in primary visual cortex, regardless of trial-specific predictability, but it is affected by recent trial history. Highlights* Ignoring trial history high and low temporal predictability similarly enhance response in V1 * In recent trial-history analysis, low temporal predictability enhanced responses in V1 compared to high temporal predictability * Shared regions inside primary visual cortex encode visible and partially occluded information

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bioRxiv2023

Preventing injuries: How augmented reality reduces fall risks in pseudo-natural environments

Falling is a major contributor to injury-related incidents and the 2nd most likely cause for unintentional injury deaths world-wide. Here, we therefore tested a vision aid for obstacle detection during a navigation task in pseudo-natural environments (virtually created cities). The vision aid had nine different setups (i.e. no highlighting of hazardous objects vs. eight different hit / false alarm ratios [cue validity]). Elderly and healthy, young adults completed the navigation task. As in real life, elderly walked slower and fell more often in pseudo-natural environments, suggesting the ecological validity of such safe experimental setups to test hazardous situations. Importantly, the vision aid reduced the risk of falling (by up to 33 %) for both age groups. Thus, our study highlights that a vision aid which augments reality could be a substantial contributor in preventing falls and related injuries, decreasing the financial burden on the health system and increasing life quality.

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bioRxiv2022

Seeing and Extrapolating motion trajectories share common informative activation patterns in primary visual cortex

The natural environment is dynamic and moving objects become constantly occluded, engaging the brain in a challenging completion process to estimate where and when the object might reappear. Although motion extrapolation is critical in daily life - imagine crossing the street while an approaching car is occluded by a larger standing vehicle - its neural underpinnings are still not well understood. While the engagement of low-level visual cortex during dynamic occlusion has been postulated, most of the previous group-level fMRI-studies failed to find evidence for an involvement of low-level visual areas during occlusion. In this fMRI-study, we therefore used individually-defined retinotopic maps and multivariate pattern analysis to characterize the neural basis of visible and occluded motion in humans. To this end, participants learned velocity-direction pairings (slow motion-upwards; fast motion-downwards or vice versa) during a training phase without occlusion and judged the stimulus direction, based on its velocity, during a following test phase with occlusion. We find that occluded motion direction can be predicted from the activity patterns during visible motion within low-level visual areas, supporting the notion of a mental representation of motion trajectory in these regions during occlusion. Highlights* Dynamically occluded information is processed in low-level visual cortex * Specific regions inside low-level visual areas encode visible and dynamically occluded information * Overlap of visible and occluded informative activity patterns in the visual field suggest shared computational circuits in primary visual cortex

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bioRxiv2021

Entering into a self-regulated learning mode prevents detrimental effect of feedback removal on memory

Recently, we provided causal evidence that self-regulated dopamine signaling enhanced long-term memory formation in the absence of any external feedback or reward (Ripolles et al., 2016, 2018) if a congruent meaning inferred from semantic context (DA-dependent learning), while DA-signals were absent if no congruent meaning could be inferred (DA-independent learning). Here, we investigated the interaction of self-regulated learning with externally-regulated DA-signalling by providing external performance feedback in the first or second half of trials. We found that removing feedback during DA-dependent learning lowered subsequent recognition rates a day later, whereas recognition remained high in the group which received feedback only in the second half. In contrast, feedback modestly enhanced recognition rates for both groups for DA-independent learning. Our findings suggest that external reinforcers can selectively impair DA-dependent memories if internal DA-dependent processes are not already established and highlights the relevance of self-regulated learning in education to support stable memory formation.

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bioRxiv2021

Minimal interplay between explicit knowledge, dynamics of learning and temporal expectations in different, complex uni- and multisensory contexts

While temporal expectations (TE) generally improve reactions to temporally predictable events, it remains unknown how temporal rule learning and explicit knowledge about temporal rules contribute to performance improvements and whether any contributions generalise across modalities. Here, participants discriminated the frequency of diverging auditory, visual or audiovisual targets embedded in auditory, visual or audiovisual distractor sequences. Temporal regularities were manipulated run-wise (early vs. late target within sequence). Behavioural performance (accuracy, RT) plus measures from a computational learning model all suggest that temporal rule learning occurred but did not generalise across modalities, that dynamics of learning (size of TE effect across runs) and explicit knowledge have little to no effect on the strength of TE, and that explicit knowledge affects performance - if at all - in a context dependent manner: only under complex task regimes (unknown target modality) might it partially help to resolve response conflict while it is lowering performance in less complex environments..

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bioRxiv2021

Cross-modal perceptual enhancement of unisensory targets is uni-directional and does not affect temporal expectations

Previous studies demonstrated that redundant target stimuli can enhance performance due to multisensory interplay and interactively facilitate performance enhancements due to temporal expectations (TE; faster and accurate reactions to temporally expected targets). Here we tested whether other types of multisensory interactions - i.e. interactions evoked by temporally flanking irrelevant stimuli - can result in similar performance patterns and boost not only unisensory target perception (multi-vs. unisensory sequences) but also unisensory temporal expectations (expected vs. unexpected). To test our hypothesis, we presented sequences of 12 stimuli (10 Hz) which either consisted of auditory (A), visual (V) or alternating auditory-visual stimuli (e.g. A-V-A-V-...) with either auditory (AV(A)) or visual (AV(V)) targets. Participants had to discriminate target frequency which was unpredictable by temporal regularities (expected vs. unexpected target positions) and by stimulation sequence (A, V, AV(A), AV(V)). Moreover, we ran two experiments in which we presented redundant multisensory targets and manipulated the speed of the stimulation sequence (10 vs. 15 Hz stimulus trains) to control whether the results of Experiment 1 depended on sequence speed. Performance for unisensory targets was affected by temporally flanking distractors, with multisensory interactions selectively improving unisensory visual target perception. Yet, only redundant multisensory targets reliably affected TEs. Together, these results indicate that cross-modal facilitation of unisensory target perception in fast stimulus streams is uni-directional, but also differs from multisensory interactions evoked by redundant targets; more specifically, it appears to be context-dependent (task, design etc.) whether unisensory stimulation (unlike redundant target stimulation) allows for the generation of temporal expectations.

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bioRxiv2021

Context dependency of time-based event-related expectations for different modalities

Expectations about the temporal occurrence of events (when) are often tied with the expectations about certain event-related properties (what and where) happening at these time points. For instance, slowly waking up in the morning we expect our alarm clock to go off; however, the longer we do not hear it the more likely we already missed it. However, most current evidence for complex time-based event-related expectations (TBEEs) is based on the visual modality. Here we tested whether TBEEs can also act cross-modally. To this end, visual and auditory stimulus streams were presented which contained early and late targets embedded among distractors (to maximise temporal target uncertainty). Foreperiod-modality-contingencies were manipulated run-wise so that visual targets either occurred early in 80% of trials and auditory targets occurred late in 80 % of trials or vice versa. Participants showed increased sensitivity for expected auditory early/visual late targets which increased over time while the opposite pattern was observed for visual early/auditory late targets. A benefit in reaction times was only found for auditory early trials. Together, this pattern of results suggests that context-dependent TBEEs for auditory targets after short foreperiods (be they correct or not) dominated and determined which modality became more expected at the late position irrespective of the veridical statistical regularity. Hence, TBEEs in cross-modal and uncertain environments are context-dependent, shaped by the dominant modality in temporal tasks (i.e. auditory) and only boost performance cross-modally when expectations about the event after the short foreperiod match with the run-wise context (i.e. auditory early/visual late).

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bioRxiv2019

Information-based taste maps in insular cortex are shaped by stimulus concentration

Taste processing is an essential ability in all animals signaling potential harm or benefit of ingestive behavior. Although the peripheral taste coding is well understood, current evidence for central taste processing remains contradictory. To address this issue, human participants judged pleasantness and intensity of low and high-concentration tastes (salty, sweet, sour, bitter) in two fMRI-experiments. High-resolution fMRI and multivariate pattern analysis were used to characterize taste-related informational content in human gustatory cortex (GC). Clusters within GC were narrowly tuned to specific tastants consistently across tasks. Importantly, taste concentrations completely altered the spatial layout of putative taste-specific maps with distinct, non-overlapping patterns for each taste category at different concentration levels. Together, our results point at population-level representations in human GC as a complex function of taste category and concentration.

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bioRxiv2018

Intrinsically regulated learning is modulated by synaptic dopamine availability

We recently provided evidence that an intrinsic reward-related signal--triggered by successful learning in absence of any external feedback--modulated the entrance of new information into long-term memory via the activation of the dopaminergic midbrain, hippocampus, and ventral striatum (the SN/VTA-Hippocampal loop; Ripolles et al., 2016). Here, we used a double-blind, within-subject randomized pharmacological intervention to test whether this learning process is indeed dopamine-dependent. A group of healthy individuals completed three behavioural sessions of our learning task after the intake of different pharmacological treatments: a dopaminergic precursor, a dopamine receptor antagonist or a placebo. Results show that the pharmacological intervention bidirectionally modulated behavioral measures of both learning and pleasantness, inducing memory benefits after 24 hours only for those participants with a high sensitivity to reward. These results provide causal evidence for a dopamine-dependent mechanism instrumental in intrinsically regulated learning, and further suggest that subject-specific dopamine sensitivity drastically alters learning success.

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