Biology subjects

Niemeier, M.

Publications and source records attributed to Niemeier, M..

9 recordsLinked to original sources

bioRxiv2026

Precise measurement of rodent drinking using CLiQR (Capacitive Lick Quantification in Rodents)

Accurate quantification of rodent licking behavior is essential for studies of fluid intake, including investigations of alcohol use disorder and obesity. Lickometry systems vary widely in sensing modality, cost, scalability, and data resolution. Also, many available systems require specialized housing or store only binary lick/no lick data based on thresholding. Here, we present CLiQR (Capacitive Lick Quantification in Rodents), an open-source capacitive lickometry system designed for high-throughput recording of licking behavior in home-cage environments while preserving the full capacitance time series. The system uses MPR121 capacitive sensors connected to custom metal-tipped serological pipette sippers and a centralized desktop computer to record data from up to 24 mice concurrently, with capacity for two-bottle choice experiments. Validation experiments demonstrated that the capacitive signals reliably distinguish licking from non-licking interactions. Total lick counts showed a positive correlation with measured fluid consumption (R2 = 0.849, p < 0.0001), confirming that detected events provide a meaningful proxy for intake. All information necessary to reproduce the system is shared openly in this manuscript and online. By combining scalability, full-trace data acquisition, and low cost, CLiQR provides a flexible and extensible platform for high-throughput behavioral neuroscience experiments and enables retrospective improvement of lick-detection algorithms.

animal behavior and cognition↗

bioRxiv2025

From Tasks to Topology: Dorsal and Ventral Streams Emerge in Optimized Neural Networks

The primate visual system is organized into dorsal and ventral pathways, classically linked to visuomotor control and perception. A long-standing question is whether this division reflects intrinsic architectural priors or emerges from task demands. We trained a single convolutional network to perform classification and grasp prediction of 3D objects, without imposing modular structure. Dual-stream topology - functionally distinct visuomotor and perceptual pathways - emerged spontaneously with rich cross-communication. Shapley value analyses revealed that action- and perception-selective features developed progressively across depth, reflecting task-driven hierarchical specialization. Time-resolved EEG showed that model activity mapped onto dissociable temporal components in human cortex: ventral-aligned signals emerged early and late, where dorsal- and ventral-aligned responses coincided in the intervening interval. These results demonstrate that task optimization alone can explain core features of dorsal-ventral organization, and that distinct temporal roles for perception and action arise naturally atop a shared feedforward scaffold, without requiring architectural hard-coding or recurrence.

neuroscience↗

bioRxiv2025

Action intentions result in the task-specific integration of object features

Theories of object-based attention suggest that attending to an object binds its features together. Yet, there is a growing body of work to suggest that the intention to grasp an object can alter the representation of features such that they are separately represented during different stages of motor planning and execution, whereas some object features such as shape and size might form integrated representations when afforded by motor control. However, it remains untested whether these features were integrated as an outcome of the requirements of grasping motor control, or due to attention towards the object in general. Therefore, here we investigated how task-relevancy modulates the integration of grasp-relevant object features. To this end, we recorded electroencephalography while human participants grasped or reached for objects that varied in their orientation and size. Using multivariate analyses, we found a superadditive integration of object orientation and size during action planning for grasping but not reaching. These integrated representations likely facilitated the calculation of stable grasp points as further evidenced by the representations of grasp-specific visual size and grip size emerging at similar times. Our results provide novel insights into the vital role of action intention on cognitive representations in the human brain.

neuroscience↗

bioRxiv2025

Predictive Coding Explains Asymmetric Connectivity in the Brain: A Neural Network Study

Seminal frameworks of predictive coding propose a hierarchy of generative modules, each attempting to infer the neural representation of the module one level below; the predictions are carried by top-down feedback projections, while the predictive error is propagated by reciprocal forward pathways. Such symmetric feedback connections support visual processing of noisy stimuli in computational models. However, neurophysiological studies have yielded evidence of asymmetric cortical feedback connections. We investigated the contribution of neural feedback during sensorimotor processes, in particular visual processing during grasp planning, by utilizing convolutional neural network models that had been augmented with predictive feedback and were trained to compute grasp positions for real-world objects. After establishing an ameliorative effect of symmetric feedback on grasp detection performance when evaluated on noisy stimuli, we characterized the performance effects of asymmetric feedback, similar to that observed in the cortex. Specifically, we tested model variants extended with short-, medium- and long-range feedback connections (i) originating at the same source layer or (ii) terminating at the same target layer. We found that the performance-enhancing effect of predictive coding under adverse conditions was optimal for medium-range asymmetric feedback. Moreover, this effect was most prominent when medium-range feedback originated at a level of representational abstraction that was proximal to the input layer, in contrast to more distal layers. To conclude, our simulations show that introducing biologically realistic asymmetric predictive feedback improves model robustness to noisy visual stimuli in a neural network model optimized for grasp detection. Significance statementIt is commonly held that the brain predicts the causes of its sensorium via top-down neural pathways. While canonical models of predictive coding assume reciprocal feedforward and feedback connections, functional evidence highlights the importance of non-reciprocal asymmetric feedback, whose role remains poorly understood, particularly in sensorimotor functions. Using neural network models of grasp planning, we characterized optimal pathlengths and source regions for asymmetric feedback facilitating visuomotor processing of noisy sensory inputs. Our findings show that medium-range feedback from early layers marks a sweet spot, incorporating optimal distance between the neural representations of source/target layers and representational abstraction of the feedback source. This intimates an uncharted role of intermediate brain areas along the visuomotor stream as a source of predictive signals.

neuroscience↗

bioRxiv2025

A Meta-analysis of Perceptual Pseudoneglect reveals the Functional Anatomy of Perceptual Judgements

Major evidence for a right-hemisphere dominance of the brain in spatial and/or attentional tasks comes from lesion studies in patients with spatial neglect. However, the neuroanatomy of the different forms of neglect remains a matter of debate, and it remains unclear how dysfunctions in neglect relate to intact processes. In the healthy brain, perceptual pseudoneglect has been considered to be a phenomenon complementary to specific subtypes of neglect as observed in paradigms such as the line bisection task. Therefore, the current study investigated the intact functional anatomy of perceptual pseudoneglect using a meta-analysis to compensate for some of the limitations of individual imaging studies. We collated the data from 24 articles that tested 952 participants with a range of paradigms (landmark task, line bisection, grating-scales task, and number line task) obtaining 337 foci. Using Activation Likelihood Estimation (ALE) we identified a right-hemisphere biased network of cortical areas, including superior and intraparietal regions, the intraoccipital sulcus together with other occipital regions, as well as inferior frontal areas that were associated with perceptual pseudoneglect in partial agreement with lesion studies in patients with neglect. Our study is the first meta-analysis on the mechanisms underlying perceptual judgments which have been shown to give rise to perceptual pseudoneglect.

neuroscience↗

bioRxiv2024

Red means heavy: Action intentions reactivate representations of task-relevant cognitive cues

Recent research shows that the intention to act on an object alters its neural representation in ways as afforded by underlying sensorimotor processes. For example, the intention to grasp and pick up an object results in representations of the objects weight. But these representations become grasp-specific only immediately before object lift if weight information is relayed through object material. This feature triggers earlier representations regardless of intention probably because material-weight contingencies are overlearned. By contrast, recently learned weight cues should be recalled deliberately during grasp planning resulting in early grasp-specific representations. Here, we examined how action intentions affect the representation of newly acquired colour-weight contingencies. We recorded electroencephalography while human participants grasped or reached for objects that varied in shape and density as indicated by their colour. Multivariate analyses revealed a grasp-specific reactivation of colour during planning that was mirrored in beta band. This suggests that task-relevancy influences the representation of colour such that previously encoded colour-weight contingencies may be reactivated as required for grasping, mediated top-down via working memory. Grasp-specific representations of shape and colour were also present in theta band, perhaps reflecting attentional activity. These results provide novel insights into the interplay between cognition and motor planning processes. Significance StatementRecent research shows that the object feature weight, conveyed via highly overlearned material-weight contingencies, is more prominently represented within electrophysiological signals when people intend to grasp an object to lift it vs. reach for it. However, such differences occur late, immediately before object lift. Our study is the first to show that newly learned colour-weight contingencies yield early task-specific representations during action planning; we find that colour/weight representations, forming 140-210 ms after object onset, reactivate around 270 ms during grasp, but not reach planning, with the same pattern arising for beta band. These data suggest that the brain deliberately processes weight information depending on intention, arguably involving working memory representations. Our results highlight the interplay of cognition and motor planning.

neuroscience↗

bioRxiv2023

Computation on demand: Action-specific representations of visual task features arise during distinct movement phases

It is commonly held that computations of goal-directed behaviour are governed by conjunctive neural representations of the task features. However, support for this view comes from paradigms with arbitrary combinations of task features and task affordances that require representations in working memory. Therefore, in the present study we used a task that is well-rehearsed with task features that afford minimal working memory representations to investigate the temporal evolution of feature representations and their potential integration in the brain. Specifically, we recorded electroencephalography data from human participants while they first viewed and then grasped objects or touched them with a knuckle. Objects had different shapes and were made of heavy or light materials with shape and weight being features relevant for grasping but not for knuckling. Using multivariate analysis, we found that representations of object shape were similar for grasping and knuckling. However, only for grasping did early shape representations reactivate at later phases of grasp planning, suggesting that sensorimotor control signals feed back to early visual cortex. Grasp-specific representations of material/weight only arose during grasp execution after object contact during the load phase. A trend for integrated representations of shape and material also became grasp-specific but only briefly during movement onset. These results argue against the view that goal-directed actions inevitably join all features of a task into a sustained and unified neural representation. Instead, our results suggest that the brain generates action-specific representations of relevant features as required for the different subcomponent of its action computations. Significance statementThe idea that all the features of a task are integrated into a joint representation or event file is widely supported but importantly based on paradigms with arbitrary stimulus-response combinations. Our study is the first to investigate grasping using electroencephalography to search for the neural basis of feature integration in such a daily-life task with overlearned stimulus-response mappings. Contrary to the notion of event files we find limited evidence for integrated representations. Instead, we find that task-relevant features form representations at specific phases of the action. Our results show that integrated representations do not occur universally for any kind of goal-directed behaviour but in a manner of computation on demand.

neuroscience↗

bioRxiv2021

Saccades and pre-saccadic stimulus repetition alter cortical network topology and dynamics: evidence from EEG and graph theoretical analysis

Parietal and frontal cortex are involved in saccade generation, but their output signals also modify visual signals throughout cortex. These signals produce well-documented behavioral phenomena (saccades, saccadic suppression, various perisaccadic perceptual distortions) but their underlying influence on cortical network dynamics is not known. Here, we combined electroencephalography (EEG) with frequency-dependent source localization and graph theory analysis (GTA) to understand how saccades and pre-saccadic visual stimuli interactively alter cortical network dynamics in humans. 21 participants viewed series of 1-3 vertical or horizontal grids, followed by grid with the opposite orientation just before a horizontal saccade or continued fixation. EEG signals from the presaccadic interval (cue + 200ms, or equivalent fixation period) were used for source localization. Source localization (saccade - fixation) identified bilateral dorsomedial frontoparietal activity across frequency bands, whereas stimulus repetition produced band-specific modulations in left prefrontal, posterior parietal, and central-superior frontal and/or parietal cortex, with significant saccade-repetition interactions in frontal and parietal regions. GTA analysis revealed a saccade-specific functional network with major hubs in inferior parietal cortex (alpha) and the frontal eye fields (beta), and major saccade-repetition interactions in left prefrontal (theta) and supramarginal gyrus (gamma). Overall, quantitative measures of whole-brain network topology and dynamics (segregation, integration, synchronization, complexity) were enhanced during the presaccadic interval, but repetition interactions reduced synchronization and complexity. These results show that presaccadic signals have widespread, coherent influence on cortical network dynamics, likely responsible for both saccade production and the perceptual phenomena associated with saccades. HighlightsO_LISource localization & graph theory were used to analyze presaccadic EEG signals C_LIO_LIPresaccadic signals produced band-specific modulations/hubs in parietofrontal cortex C_LIO_LIFrontal/parietal eye fields showed extensive functional connectivity across all lobes C_LIO_LIPresaccadic stimulus repetition further modulated functional network connectivity C_LIO_LISaccades and repetition both influenced network clustering, integration, & complexity C_LI

neuroscience↗

bioRxiv2018

Multimodal evidence on shape and surface information in individual face processing

The significance of shape and surface information for face perception is well established, yet their relative contribution to recognition and their neural underpinnings await clarification. Here, we employ image reconstruction to retrieve, assess and visualize such information using behavioral, electroencephalography and functional magnetic resonance imaging data.\n\nOur results indicate that both shape and surface information can be successfully recovered from each modality but that the latter is better recovered than the former, consistent with its key role for face representations. Further, shape and surface information exhibit similar spatiotemporal profiles, rely on the extraction of specific visual features, such as eye shape or skin tone, and reveal a systematic representational structure, albeit with more cross-modal consistency for shape than surface.\n\nThus, the present results help elucidate the representational basis of individual face recognition while, methodologically, they showcase the utility of image reconstruction and clarify its reliance on diagnostic visual information.

neuroscience↗