Biology subjects

Wilming, N.

Publications and source records attributed to Wilming, N..

6 recordsLinked to original sources

bioRxiv2023

Brainstem arousal systems adaptively shape large-scale cortical interactions for flexible decision-making

Most perceptual decisions entail a flexible mapping from sensory input to motor output. Flexible input-output mapping is reflected in correlated variability within the cortical network involved in perceptual decisions. Here, we tested the idea that brainstem arousal systems are involved in flexible input-output mapping and changes in cortical correlated variability. We combined brainstem fMRI, pupillometry, and time-resolved assessment of the intrinsic correlations between cortical population codes for stimulus and action. Human participants reported the orientation of visual stimuli by button presses, while the required stimulus-response mapping rule could undergo hidden and unpredictable changes. Rule switches evoked brainstem and pupil responses as well as changes in computational model-inferred, latent variables. These variables governed participants rule-switching behavior and pupil responses. Brainstem activity and pupil dilation preceded increases in the strength of correlations between cortical stimulus and action codes. Brainstem arousal systems may promote the reorganization of sensorimotor cortical pathways for flexible decisions.

neuroscience↗

bioRxiv2022

Large-Scale Circuit Configuration for Flexible Sensory-Motor Decisions

Humans and non-human primates can flexibly switch between different arbitrary mappings from sensation to action to solve a cognitive task. It has remained unknown how the brain implements such flexible sensory-motor mapping rules. Here, we uncovered a dynamic reconfiguration of task-specific correlated variability between sensory and motor brain regions. Human participants switched between two rules for reporting visual orientation judgments during fMRI recordings. Rule switches were either signaled explicitly or inferred by the participants from ambiguous cues. We used behavioral modeling to reconstruct the time course of their belief about the active rule. In both contexts, the patterns of correlations between ongoing fluctuations in stimulus- and action-selective activity across visual and action-related brain regions tracked participants belief about the active rule. The rule-specific correlation patterns broke down around the time of behavioral errors. We conclude that internal beliefs about task state are instantiated in brain-wide, selective patterns of correlated variability.

neuroscience↗

bioRxiv2020

Disentangling Decision-related Feedforward and Feedback Signals in Human Cortex

Perceptual decisions entail the accumulation of sensory evidence for a particular choice towards an action plan. An influential framework holds that sensory cortical areas encode the instantaneous sensory evidence and downstream, action-related regions accumulate this evidence. The large-scale distribution of this computation across the cerebral cortex has remained largely elusive. We developed a regionally-specific magnetoencephalography decoding approach to exhaustively map the dynamics of stimulus- and choice-specific signals across the human cortical surface during a visual decision. Comparison with the evidence accumulation dynamics inferred from behavior enabled us to disentangle stimulus-dependent and endogenous components of choice-predictive activity across the visual cortical hierarchy. The endogenous component was present in primary visual cortex, expressed in a low (< 20 Hz) frequency-band, and its time course tracked, with delay, the build-up of choice-predictive activity in (pre-)motor regions. Our results are consistent with choice-specific cortical feedback signaling in a specific frequency channel during decision formation.

neuroscience↗

bioRxiv2020

Normative Circuit Dynamics Across Human Cortex During Evidence Accumulation in Changing Environments

Many decisions under uncertainty entail the temporal accumulation of evidence that informs about the state of the environment. When environments are subject to hidden changes in their state, maximizing accuracy and reward requires non-linear accumulation of the evidence. How this adaptive, non-linear computation is realized in the brain is unknown. We analyzed human behavior and cortical population activity (measured with magnetoencephalography) recorded during visual evidence accumulation in a changing environment. Behavior and decision-related activity in cortical regions involved in action planning exhibited hallmarks of adaptive evidence accumulation, which could also be implemented by a recurrent cortical microcircuit. Decision dynamics in action-encoding parietal and frontal regions were mirrored in a frequency-specific modulation of the state of visual cortex that depended on pupil-linked arousal and the expected probability of change. These findings link normative decision computations to recurrent cortical circuit dynamics and highlight the adaptive nature of decision-related feedback to sensory cortex.

neuroscience↗

bioRxiv2017

Entorhinal cortex receptive fields are modulated by spatial attention, even without movement.

Grid cells have been identified in the entorhinal cortex in a variety of species and allow for the precise decoding of position in space (1-7). Along with potentially playing an important role in navigation, grid cells have recently been hypothesized to make a general contribution to mental operations, including remembering the past and thinking about the future (8,9). A prerequisite for this hypothesis is that grid cell activity does not critically depend on physical movement. Directed attention, which contributes to virtually all mental operations and can be separated from physical movement provides a good test case to investigate this hypothesis. Overt attention in the form of fixational eye movements leads to grid-like firing fields in the monkey entorhinal cortex (3). Here we show that movement of covert attention, without any physical movement, also elicits spatial receptive fields with a triangular tiling of the space. In monkeys trained to maintain central fixation while covertly attending to a stimulus moving in the periphery we identified a significant population (20/141, 14% neurons at a FDR<5%) of entorhinal cells with spatially structured receptive fields. Further, we were able to identify a population of neurons that were labeled as grid cells on an individual basis. This contrast with our recordings obtained in the hippocampus, where grid-like representations were not observed. Our results provide compelling evidence that neurons in macaque entorhinal cortex do not rely on physical movement. Notably, these results support the notion that grid cells may be capable of serving a variety of different cognitive functions and suggest that grid cells are a versatile component of many neural algorithms.

neuroscience↗

bioRxiv2017

Aversive Learning Changes Face-Viewing Strategies, as Revealed by Model-Based Fixation-Pattern Similarity Analysis

Animals can effortlessly adapt their behavior by generalizing from past experiences, and avoid harm in novel aversive situations. In our current understanding, the perceptual similarity between learning and generalization samples is viewed as one major factor driving aversive generalization. Alternatively, the threat-prediction account proposes that perceptual similarity should lead to generalization to the extent it predicts harmful outcomes. We tested these views using a two-dimensional perceptual continuum of faces. During learning, one face is conditioned to predict a harmful event, whereas the most dissimilar face stays neutral; introducing an adversity gradient defined only along one dimension. Learning changed the way how humans sampled information during viewing of faces. These occurred specifically along the adversity gradient leading to an increased dissimilarity of eye-movement patterns along the threat-related dimension. This provides evidence for the threat-prediction account of generalization, which conceives perceptual factors to be relevant to the extent they predict harmful outcomes.

neuroscience↗