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Meinzer, M.

Publications and source records attributed to Meinzer, M..

15 recordsLinked to original sources

Brain Regions Involved in Object-Location Memory Across the Human Lifespan: A Systematic Review and Activation Likelihood Estimation Meta-Analysis of Task-Based fMRI

BackgroundThe ability to remember object locations in real life is a fundamental cognitive process that supports goal-directed behavior and is particularly vulnerable to aging and neurodegenerative disease. Despite a growing body of functional magnetic resonance imaging (fMRI) research on object-location memory (OLM), the neural substrates of establishing and retrieving location information are largely unknown. ObjectiveThis systematic review and coordinate-based meta-analysis aimed to identify brain regions consistently activated during OLM in healthy adults, primarily for encoding and - on an exploratory basis - for retrieval, and to characterize age-related differences in OLM-related neural activity. MethodsA systematic search was conducted across three databases (PubMed, PsycInfo, Cochrane Library) up to February 2026. Studies employing task-based fMRI during the encoding and retrieval of object-location associations in healthy adults were eligible. Age-related differences in OLM-related brain activity were examined via narrative synthesis. An activation likelihood estimation (ALE) meta-analysis was performed on studies reporting stereotactic peak coordinates. The review was pre-registered on PROSPERO (CRD420251023695). ResultsTwenty-one studies comprising 637 participants were included in the systematic review, with 12 studies being eligible for the encoding ALE meta-analysis. The retrieval ALE meta-analysis was not possible due to the limited number of included studies and reported foci. The systematic review indicated that OLM encoding consistently recruited bilateral fusiform gyri and parahippocampal cortices, with additional engagement of parietal and prefrontal regions across individual studies, whereas OLM retrieval recruited mainly the hippocampus and precuneus. The coordinate-based ALE meta-analysis revealed two significant clusters of activation during OLM encoding: a left-lateralized cluster encompassing the fusiform gyrus, parahippocampal gyrus, and inferior temporal gyrus (peak MNI: -28, -38, -16), and a right-hemisphere cluster spanning the parahippocampal gyrus and fusiform gyrus (peak MNI: 30, -46, -16). Age-related differences, based on a small number of studies with direct age comparison, pointed toward reduced activity in posterior cortical regions coupled with increased activity in prefrontal and midline regions. Additionally, younger adults showed greater hippocampal activation for successful than unsuccessful spatial retrieval, whereas older adults showed the opposite pattern. ConclusionThe systematic review and meta-analysis identify the fusiform gyri and parahippocampal cortices as the most reliably activated regions during OLM encoding, locating OLM formation primarily within the ventral visual-to-medial-temporal processing stream. Retrieval additionally engaged the hippocampus and precuneus, consistent with their established roles in episodic memory. Age-related differences included reduced posterior cortical encoding activity in older adults, a reversal of the hippocampal activation pattern during retrieval, and weaker suppression of midline regions during task performance. The identified encoding pathway may inform targeted network-level interventions such as non-invasive brain stimulation to counteract cognitive decline in aging and neurodegenerative disease. Highlights- First systematic review and coordinate-based meta-analysis of task-based fMRI during encoding and retrieval of object-location memories (OLMs). - Activation likelihood estimation (ALE) identified bilateral fusiform gyrus and parahippocampus as the most consistent encoding regions, supporting a ventral-dominant input pathway. - Hippocampus and precuneus were the most consistent OLM retrieval regions, suggesting an encoding-retrieval dissociation. - Age-related encoding differences centered on reduced fusiform and parahippocampal subsequent-memory effects, with an altered anterior-hippocampal response in older adults.

neuroscience↗

Inhibition in motion: Test-retest reliability of inhibitory kinematics in a go/no-go mouse tracking task

Response inhibition, the ability to suppress contextually inappropriate actions, is a cornerstone of cognitive control and is commonly assessed using paradigms such as the go/no-go task. However, traditional go/no-go paradigms rely on binary outcomes such as commission errors, which offer limited insight into the dynamic, graded behavioral adjustments underlying successful stopping. The present study developed a novel mouse-tracking go/no-go paradigm with a dynamic start to capture inhibitory processes during ongoing execution. Twenty-three healthy young adults completed the task in two sessions separated by approximately one week to evaluate the test-retest reliability of standard behavioral measures (error rates and reaction times), and three kinematic features: path length, mean velocity, and mean acceleration. Results revealed robust differences between go and no-go trials across all measures. Successful inhibition was characterized by significantly shorter path lengths and reduced mean velocity and acceleration compared to go trials. Critically, all measures demonstrated moderate-to-good test-retest reliability across sessions, with intraclass correlation coefficients ranging from .75 to .85 for go trials and from .59 to .83 for no-go trials. These findings establish construct validity and psychometric reliability of the current mouse-tracking go/no-go paradigm. The demonstrated stability of these measures provides the methodological foundation for their use in cross-sectional, longitudinal, and intervention research targeting inhibitory control.

neuroscience↗

Temporo-Occipital and Medial Temporal Networks Underlying Object-Location Learning

Object-location memory (OLM), a fundamental component of spatial memory, is essential for everyday functioning yet declines with aging and neurodegenerative disorders. Functional neuroimaging studies have consistently implicated medial temporal lobe (MTL) structures, including the hippocampus and parahippocampal gyrus, as well as medial and lateral temporo-occipital regions, in object-location associative learning. However, the neural mechanisms and functional network interactions supporting OLM acquisition remain largely unknown. To address this gap, we examined twenty healthy adults (18-45 years) performing an object-location learning task during functional MRI. As a first main finding, task-related functional connectivity analyses revealed enhanced coupling between MTL structures, ventral visual regions, and temporo-occipital cortices during OLM learning. Secondly, stronger connectivity within this network was associated with higher learning accuracy, highlighting the behavioral relevance of coordinated cortical-MTL interactions. Thirdly, these connectivity patterns were not static but evolved across learning stages: interregional coupling was strongest during early learning and progressively attenuated as performance stabilized, suggesting sharpening and increased efficiency of network interactions with learning. Together, our results provide mechanistic insight into OLM acquisition at the functional network level and offer an evidence-based framework for identifying target networks to enhance spatial memory through non-invasive brain stimulation.

neuroscience↗

Normative Deviations Reveal Task-Evoked and Clinical Network Reorganization

Understanding how cognitive demands and pathology reshape large-scale functional connectivity (FC) requires methods that are both multivariate and region-specific. Here we introduce One-class SVM-based Connectome Anomaly Recognition (OSCAR), a normative modelling framework that detects condition-related deviations in the multivariate connectivity profile of a brain region. OSCAR learns the distribution of region-to-whole-brain connectivity patterns given a reference state sample (e.g. resting-state data; RS) using a one-class support vector machine (OCSVM). The trained models are then applied to FC profiles from a target condition (e.g., task or patient group). The outlier proportions are used to quantify the difference between the reference and target condition. We validated OSCAR on three diverse tasks and a patient cohort with early psychosis. OSCAR consistently identified condition-sensitive regions in networks known to support conflict processing, object-location memory, lexical learning, and early psychosis, respectively, including thalamic and basal ganglia regions. Moreover, it detected additional well-established task- or disease-relevant parcels not captured by the comparison method permutation-based multivariate analysis of variance (perMANOVA). Regions flagged by OSCAR were at least as close, and often closer, to independent task-activation findings than those identified by perMANOVA. These results demonstrate that OSCAR provides an interpretable, region-centred normative modelling approach that is sensitive to subtle multivariate FC deviations, and offers a practical tool for mapping condition-specific reconfigurations of functional brain networks with high external validity, in both experimental and clinical settings.

neuroscience↗

Harmonizing the stimulation dose of focal tDCS across target sites

Non-invasive brain stimulation is an established tool for modulating neural activity that holds promise for advancing both cognitive neuroscience and clinical interventions. Focal transcranial direct current stimulation (tDCS), using center-surround electrode montages, enables more region-specific targeting. Although computational models can simulate individual electric fields, no existing approach enables the prospective individualization of electrode placement while standardizing the dose across targeted brain regions. In the current preparatory methodological study, we present a modeling-based framework that harmonizes the electric field strength between different target regions at the group level, but preserves inter-individual variability. This enables systematic examination of dose-response relationships and their regional differences. Positioning of the center-surround electrode montages is individualized to ensure focusing of the electric field on the target regions. We started by defining brain targets for eight cognitive and motor functions using MRI data from 43 participants. Using field simulations, we then estimated a group-average field strength in the target regions that had led to behavioral and physiological effects in prior tDCS studies (resulting in 0.2 V/m). The radii of the center-surround montages were optimized for each target region to achieve the intended field strength while maximizing focality. Validation in an independent sample (n=53) confirmed that the intended target field strength is achieved on average for new participants. The described computational tools are made available as open-source software, allowing other researchers to apply our individualization framework with parameters (target regions and target field strengths) tailored to their specific research questions; and are currently being implemented in a multi-center study involving approximately 1,000 datasets.

neuroscience↗

Multimodal Imaging-Based Targeting Approach for Network-Level Brain Stimulation

BackgroundNeural network effects of transcranial direct current stimulation (tDCS) are poorly understood. Here, we introduce an empirically informed, multimodal functional magnetic resonance imaging (fMRI) based framework suited for guiding stimulation target selection and hypothesis-based data analysis in focal tDCS-fMRI studies. MethodsWe illustrate our approach using data of 37 healthy individuals (19 females; mean {+/-} SD age = 25.8 {+/-} 5.9) recruited from a multicenter tDCS-fMRI study. Participants completed resting-state (RS- and task-fMRI (object-location memory, OLM, or associative picture-pseudoword learning, APPL, experiments) with placebo tDCS. Seed-based RS data analysis identified the functional networks originating from project-specific target regions for focal tDCS (right occipito-temporal cortex, rOTC; left ventral IFG, lvIFG) and also established their test-retest reliability using intraclass correlation coefficients (ICC). Dice coefficients analyzed the overlap between the seeded RS- and task-evoked networks. This aimed to identify task-active regions potentially affected by downstream neural network effects from the target regions. ResultsSeed-based analyses identified two highly reliable ventral visual-limbic (rOTC) and language-related networks (lvIFG), with >72-77% of voxels showing good-to-excellent TRR (ICC [≥] 0.75). Only a subset of voxels identified by the RS analyses overlapped with activity elicited by the experimental paradigms (ranging from 7.5-55%), with larger correspondence for the OLM task (Dice OLM: 0.249-0.349; APPL 0.065-0.106). Therefore, the degree of potential tDCS network effects varied substantially depending on the target region, the extent of its functional network and task-specific activity patterns. Degree of correspondence was further mediated by the selected contrasts-of-interest in the task-based analyses, with more conservative control conditions resulting in reduced overlap. ConclusionWe established a principled, multimodal fMRI framework bridging a critical gap in neuromodulation research. By integrating reliable intrinsic connectivity maps with task-evoked activity patterns, we provide a method to prospectively identify network-level targets for focal brain stimulation and to generate hypotheses for data analyses in tDCS-fMRI studies. This approach paves the way for investigating modulation of specific functional networks, shifting the rationale from stimulating an isolated brain region to strategically targeting key nodes within a predefined functional pathway.

neuroscience↗

Deep learning to overcome human error and bias in electrode position extraction in tDCS-fMRI studies

Combining transcranial direct current stimulation (tDCS) with fMRI enables investigation of stimulation effects, while structural MRI verifies electrode positioning, critical for focal montages where minor misplacements reduce target current dose. Currently, no fully automated methods exist for precise electrode extraction from MRI. We developed an Attention U-Net-based deep learning approach to automate electrode detection in focal tDCS-fMRI studies, using structural pointwise-encoding time reduction with radial acquisition (PETRA) MRI scans from a multicenter trial (N = 392 images; 1,568 electrodes, https://www.memoslap.de/en/home/). Performance was compared to manual and semi-automated methods for a 3x1 montage (three cathodes around a central anode). The network achieved robust segmentation (Dice Score = 0.76, Hausdorff distance = 36.76 mm), identifying all electrodes in 95% of cases (323/340). These metrics compared network-segmented electrodes to highly accurate, manually segmented electrodes, which are also called "ground truth". Linear mixed-effects models on 52 "ground truth" images showed deep learning outperformed manual and semi-automated methods, aligning best with ground truth. Fully/semi-automated methods comparison of 290 images showed highest agreement (ICC = 0.990, bias = 1.3 mm), while manual extraction exhibited larger biases (-5.77 to -7.06 mm) and systematic errors. The automated approach overcomes manual limitations by improving precision, eliminating human variability and bias, and enabling scalability for large studies. It sets a new standard for electrode verification in focal tDCS, particularly for studies requiring precise localization. The model is open-source, with future refinements discussed

neuroscience↗

Functionally Relevant and Reliable Brain Stimulation Targets for Enhancement of Novel Word-Learning

Linking word-forms and their meanings is central to language learning. Transcranial direct current stimulation (tDCS), has shown potential to enhance this process, but with variable effects. This study aimed to (1) identify reliable and functionally relevant tDCS target brain regions to enhance novel-word learning and (2) assess test-retest reliability (TRR) of behavioral and imaging outcomes. Twenty healthy individuals completed two functional magnetic resonance imaging (fMRI) sessions using parallel task versions. Participants learned picture-pseudoword associations across six learning blocks. Behavioral learning was analyzed using linear-mixed-models. Whole-brain and region-of-interest (ROI) analyses examined learning-related activity changes and their behavioral relevance. TRR was assessed using intraclass correlation coefficients (ICCs). Participants successfully acquired the novel-word forms, indexed by increased accuracy and faster latency across stages. Behavioral outcomes showed good-to-excellent TRR. The task elicited robust language-learning related activity and activity changes across stages were correlated with learning success. Task-related activity was variable, but voxels within significant clusters ([~]81%) and most ROIs showed moderate-to-excellent consistency. Power analyses confirmed a sufficient sample size for detecting the reported ICCs. Current modeling suggested that focal-tDCS can induce neurophysiologically relevant electrical field strength in the identified target regions. Hence, we identified accessible, reliable and functionally relevant cortical targets for enhancing novel-word learning. TRR results support the usefulness of the paradigm for future concurrent tDCS-fMRI research. Our study also outlines a general path towards optimization of brain stimulation studies by implementing an empirically informed approach for selecting reliable and relevant target regions and implementation of reliable experimental and imaging paradigms.

neuroscience↗

Stuck on you! Social brain stimulation increases the cognitive effort required to return to the egocentric perspective

Flexible switching between self and other perspectives is critical for adaptive social cognition and is thought to rely on the dynamic regulation of self-other representations. Although neuroimaging implicates the dorsomedial prefrontal cortex (dmPFC) and right temporoparietal junction (rTPJ) in perspective-taking, causal evidence for their specific contributions to perspective switching is lacking. Here, we applied focal transcranial direct current stimulation (f-tDCS) to the dmPFC and rTPJ while participants completed a visual perspective-taking task requiring switches between egocentric and altercentric viewpoints. Anodal stimulation to either site selectively increased the cognitive cost of switching back to the egocentric-perspective, without affecting switches into the altercentric-perspective. Rather than facilitating re-engagement with self-referential processing, stimulation enhanced altercentric persistence or impaired disengagement from the altercentric perspective. These findings provide novel causal evidence that both the dmPFC and rTPJ are involved in regulating the inhibition and updating of self-other representations during perspective switching. Results suggest that stimulation of these hubs may disrupt efficient realignment to the self, highlighting their role in maintaining an altercentric cognitive state. Future studies are required to uncover the precise neural computations that account for the comparable behavioural outcomes observed across distinct social brain hubs.

neuroscience↗

Regionally specific picture naming benefits of focal tDCS are dependent on baseline performance in older adults

AbstractWord-finding difficulty is a common challenge in older age and is linked to various neuropathological conditions associated with ageing. Transcranial direct current stimulation (tDCS) has shown promise as a cognitive enhancement tool for both healthy aging and age- related cognitive disorders. However, its effectiveness in enhancing word-finding ability remains inconsistent, especially among healthy adults. This variability is likely due to factors such as task selection, stimulation parameters, and small sample sizes. Additionally, many studies have overlooked the role of baseline performance in evaluating tDCS efficacy. In this preregistered study, we examined 72 older and 72 younger adults using a double-blind, sham-controlled design, delivering anodal focal tDCS to either the left inferior frontal gyrus or the left temporoparietal junction. Baseline naming performance and fluid intelligence were measured before stimulation. Anodal stimulation of the left inferior frontal gyrus significantly increased response speed for object and action naming in older adults, but crucially only in older adults who performed poorly during the baseline naming session. Findings demonstrate regionally specific effects of focal tDCS in healthy older individuals in greater need for naming facilitation. Notably, performance on a broad measure of fluid intelligence was unrelated to stimulation response, suggesting task specificity of this effect.

neuroscience↗

Gender imbalances in citation rates are mediated by field specific author gender distributions

Gender biases are well documented in science and typically favor male scientists. In this context, a particularly pervasive gender bias is undercitation of publications authored by women, resulting in profound negative effects on academic visibility and career advancement. This bias has been well documented in fields where author gender distributions are strongly skewed towards men (e.g., astronomy, physics, neuroscience). By investigating citation practices in a field that has traditionally been more accessible to female scientists (Speech and Language Pathology, SLP), we demonstrate that gendered citation practices are mediated by author gender distribution, rather than being a universal pattern. Specifically, our results revealed a citation pattern in SLP that (a) overall tends to favor female authors, (b) persists after controlling for potential confounding factors and, (c) is particularly strong when female authors are citing publications involving female first and senior author teams. This research also implies that the implementation of effective measures to increase the number and influence of underrepresented individuals in specific fields of science may be suitable to mitigate downstream disadvantages for career advancement of either sex.

scientific communication and education↗

The right temporoparietal junction is causally associated with embodied perspective taking

Several theories exist pertaining to the role of the right temporoparietal junction (rTPJ) in social cognition. A prominent theory claims the rTPJ is especially associated with embodied processes. In the present study we use high-definition transcranial direct current stimulation (HD-tDCS) to provide evidence that the rTPJ is causally associated with the embodied processes underpinning perspective taking. Eighty-eight young human adults were stratified to receive either rTPJ or dorsomedial prefrontal (dmPFC) anodal HD-tDCS in a sham-controlled, double-blind, repeated-measures design. Perspective tracking (line-of-sight) and perspective taking (embodied rotation) were assessed using a visuo-spatial perspective taking (VPT) task that required understanding what another person could see or how they see it, respectively. Embodied processing was manipulated by positioning the participant in a manner congruent or incongruent with the orientation of an avatar on the screen. As perspective taking, but not perspective tracking, is influenced by bodily posture, this allows the investigation of the specific causal role for the rTPJ in embodied processing. Crucially, anodal stimulation to the rTPJ increased the effect of bodily posture during perspective taking, whereas no such effects were identified during perspective tracking, thereby providing evidence for a causal role for the rTPJ in the embodied component of perspective taking. Stimulation to the dmPFC had no effect on perspective tracking or taking. Therefore, the present study provides support for theories postulating that the rTPJ is causally involved in embodied cognitive processing relevant to social functioning.\n\nSignificance StatementThe ability to understand anothers perspective is a fundamental component of social functioning. Adopting another perspective is thought to involve both embodied and non-embodied processes. The present study used high-definition transcranial direct current stimulation (HD-tDCS) and provided causal evidence that the right temporoparietal junction (rTPJ) is involved specifically in the embodied component of perspective taking. Specifically, HD-tDCS to the rTPJ, but not another hub of the social brain (dmPFC), increased the effect of body posture during perspective taking, but not tracking. This is the first causal evidence that HD-tDCS can modulate social embodied processing in a site-specific and task-specific manner.

neuroscience↗

Cultural background influences electrical stimulation effects on the social brain

ABSTRACTCultural background influences social cognition, however no study has examined brain stimulation differences attributable to cultural background. 104 young adults [52 South-East Asian Singaporeans (SEA); 52 Caucasian Australians (CA)] received anodal high-definition transcranial direct current stimulation (HD-tDCS) to the dorsomedial prefrontal cortex (dmPFC) or the right temporoparietal junction (rTPJ). Participants completed tasks with varying demands on self-other processing including visual perspective taking and episodic memory with self and other encoding. At baseline, SEA showed greater self-other integration than CA in the level one (line-of-sight) VPT task as indexed by greater interference from the alternate perspective. Anodal HD-tDCS to the dmPFC resulted in the CA performing closer to the SEA during egocentric perspective judgements. Baseline performance on level two (embodied rotation) VPT task and the self-reference effect in memory (SRE) was comparable between the two groups. In the combined sample, HD-tDCS to the rTPJ decreased the interference from the egocentric perspective during level two VPT and dmPFC HD-tDCS removed the SRE in episodic memory. Stimulation effects were comparable when baseline performance was comparable. When baseline performance differed, stimulation differences were identified. Therefore, social cognitive differences due to cultural background are an important consideration in social brain stimulation studies.\n\nHIGHLIGHTSO_LICompared with Caucasians, South-East Asians were influenced by the alternate perspective to a greater extent during level one visual perspective taking\nC_LIO_LIAnodal HD-tDCS to the dmPFC shifted Caucasians closer to the baseline performance of South-East Asians\nC_LIO_LIAnodal HD-tDCS to the dmPFC removed the self-reference effect in episodic memory in both cultural groups\nC_LIO_LIAnodal HD-tDCS to the dmPFC reduced overall memory performance in the South-East Asians but not in the Caucasian group\nC_LIO_LIAnodal HD-tDCS to the rTPJ reduced egocentric interference in a level two visual perspective taking task in both cultural groups\nC_LI

neuroscience↗

Improving cross-cultural \"mind-reading\" with electrical brain stimulation

Background: A cross-cultural disadvantage exists when inferring the mental state of others, which may be detrimental for individuals acting in an increasingly globalized world. The dorsomedial prefrontal cortex (dmPFC) is a key hub of the social brain involved in ToM. Therefore, we explored whether facilitation of dmPFC function by focal high-definition tDCS can improve cross-cultural mind-reading.\n\nMethod: 52 (26 F/M) Singaporeans performed the Caucasian version of the Reading the Mind in the Eyes Test (RMET) and received HD-tDCS to either the dmPFC or a control site (right temporoparietal junction,rTPJ) in sham-controlled, double-blinded, crossover studies. Contact with Caucasians was determined for the Singaporean cohort as a potential mediator of RMET performance and HD-tDCS response. 52 Caucasians completed the RMET during sham-tDCS and served as a comparison group.\n\nResults: A cross-cultural disadvantage on the RMET was confirmed in the Singaporean cohort and this disadvantage was more pronounced in those participants who had less contact with Caucasians. Importantly, HD-tDCS to the dmPFC improved RMET performance in those with less contact. No effect was identified for rTPJ HD-tDCS or for the age/sex control task demonstrating task and site specificity of the stimulation effects.\n\nConclusion: Electrical stimulation of the dmPFC selectively improves the rate of cross-cultural ToM inference from facial cues, effectively removing cross-cultural disadvantage that was found in individuals with lower cross-cultural exposure.

neuroscience↗

Dissociable roles for the rTPJ and dmPFC in self-other processing: a HD-tDCS study

BackgroundSocial interaction relies on the integration and distinction of self and other. The dorsomedial prefrontal cortex (dmPFC) and the right temporoparietal junction (rTPJ) are two regions consistently associated with social processes. Theories of rTPJ function in social cognition include self-other distinction, self-inhibition, or embodied mental rotation, whereas the dmPFC is associated with a wide range of social functions involving understanding and encoding information pertaining to others. However, to date, no study has provided causal evidence for dissociable roles of the rTPJ and dmPFC in social cognition.\n\nMethod52 healthy young adults were stratified into two studies and received either dmPFC or rTPJ anodal HD-tDCS in a sham-controlled, double-blinded, repeated measures design. Subjects completed a social cognitive battery measuring self-other processing across an implicit and explicit level one (line-of-sight) and level two (mental rotation) visual perspective taking tasks (VPT), as well as self and other encoding effects on episodic memory in order to test the self-reference effect (SRE).\n\nResultsStimulation of the dmPFC selectively enhanced integration of the other perspective into self as indexed by an increase in congruency effect (incongruent-congruent) across both explicit VPT tasks. It also removed the SRE in episodic memory, indexed by increasing the recognition of other-encoded words and reducing the recognition of self-encoded words. Stimulation of the rTPJ resulted in improved inhibition of the self-perspective during level two VPT only, as indexed by a reduction of the congruency effect when taking the other perspective.\n\nConclusionOur results provide the first causal evidence for dissociable roles of the dmPFC and rTPJ in social cognition. This research supports theories suggesting that rTPJ facilitates embodied mental rotation, whereas the dmPFC integrates information relevant to the other into that of the self.

neuroscience↗