Neuropsychologia

Naming pictures from the same semantic category can interfere with subsequent word retrieval. Although the left inferior frontal gyrus (LIFG) has been implicated in resolving this semantic interference, its causal role in this process remains unclear. Across three experiments, we investigated the contribution of the LIFG to interference resolution during blocked-cyclic naming. Experiment 1 tested whether continuous theta-burst stimulation over the LIFG increased semantic interference relative to vertex stimulation. Although the overall interference effect did not differ significantly between stimulation sites, exploratory analyses revealed an unexpected pattern based on the initial context (related vs. unrelated) with which items were named, suggesting that LIFG disruption affected retrieval of previously related items even when they were subsequently named in unrelated contexts. This observation motivated two further experiments examining the consequences of prior naming context more directly. Experiment 2 established that, without stimulation, interference observed in related blocks was no longer evident after the items were redistributed into unrelated blocks. Experiment 3 combined this design with cathodal or sham transcranial direct current stimulation (tDCS) over the LIFG. Planned comparisons showed that cathodal stimulation slowed naming of initially related items both within related blocks and after redistribution into unrelated blocks; corresponding comparisons for items named consistently in unrelated blocks were not significant. The similar patterns across two stimulation methods suggest that LIFG-mediated control may influence both selection under current competition and subsequent retrieval of previously competing words. These findings could be accommodated within a hybrid account in which working memory supports context-guided selection and selection-related control helps recalibrate lexical accessibility, limiting the carryover of interference into subsequent naming.

Understanding how the brain represents meaning at different levels of specificity, from general categories (bird) through combined phrases (nocturnal bird) to specific exemplars (owl), is a central question in semantic cognition and its disorders. The anterior temporal lobes (ATL) have been implicated in both activating stored conceptual representations and combining them, yet whether these two routes to conceptual content engage the ATL in the same way remains an open question. We recorded concurrent MEG-EEG from 36 participants reading 100 conceptual triads varying parametrically in specificity: general words (bird), adjective-noun phrases (nocturnal bird), and specific words (owl). Source analyses revealed a non-linear pattern in bilateral ATL (400-520ms): high-specificity concepts elicited greater activity than both low-specificity words and mid-specificity phrases. Bilateral inferior frontal cortex showed this effect with similar timing (430-630ms). N400 amplitude and ATL source activity showed a functional dissociation in their sensitivity to word frequency, ruling out a purely frequency account of the ATL and IFC effects. Results imply that accessing high-specificity concepts requires individuating stored representations among competitors, whereas phrases construct meaning through a different route. These findings extend the unified semantic hub account by revealing that computational operations within the ATL vary depending on task and stimulus demands.

Understanding how native speakers and second language (L2) learners process language differently is fundamental to theories of language acquisition, comprehension, and use. A central debate in this literature concerns the inconsistent findings in emotional prosody processing between native speakers and L2 learners, partly attributable to stimulus lexicality: some studies use real words, whereas others use pseudowords. To resolve this discrepancy, we measured fMRI responses in 15 native speakers and 15 L2 learners while they listened to Mandarin real-word and pseudoword stimuli. Both groups engaged in overlapping auditory, cognitive, and affective regions, including the auditory cortex, inferior frontal cortex, superior temporal cortex, and the temporoparietal junction. However, the two groups showed distinct responses depending on lexicality: native speakers showed stronger recruitment of temporal regions for pseudowords, whereas L2 learners showed greater frontoparietal activation for real words. These patterns were consistent across positive and negative prosody conditions. Furthermore, among L2 learners, higher proficiency was associated with greater frontal activation for real words, but not pseudowords. Together, these findings demonstrate that the differences between native speakers and L2 learners depend critically on stimulus lexicality, highlighting the role of lexicality in bilingual emotion processing.

Chinese is one of the living languages with the highest homophone densities, making homophone processing a critical component of language comprehension and orthographic decoding, as well as an ideal model for examining its cognitive mechanisms. This study assessed mono- and bi-character homophone selection function in 129 Mandarin- and Cantonese-speaking participants, including 66 cognitively healthy individuals, 17 with semantic variant (sv) primary progressive aphasia (PPA), 23 with the nonfluent/agrammatic variant (nfv) PPA, and 23 with the logopenic variant (lv) PPA. All PPA variants showed impairment in homophone selection, with most significant deficits in svPPA and lvPPA. ROC analyses demonstrated its strong diagnostic utility for distinguishing PPA from controls. Voxel-based morphometry revealed that homophone performance correlated with gray-matter volume in left anterior and inferior temporal regions, with variant-specific patterns observed. These findings described the potential role of homophone selection in diagnosing PPA syndrome in Chinese speakers, illuminate crosslinguistic influences on language impairment in PPA, and provide novel insights into the cognitive processing of homophones.

Syntax processing impairment is a defining feature of primary progressive aphasia (PPA), particularly in the nonfluent/agrammatic variant. However, current models are derived largely from Indo-European languages, and it remains unclear whether the cognitive and neuroanatomical mechanisms of syntax processing generalize to Chinese, an analytic, pro-drop language that encodes grammatical relationships primarily through word order and function words rather than inflectional morphology. Participants were recruited from the international Chinese Language Assessment in PPA cohort and included 64 individuals with PPA (19 logopenic, 15 nonfluent/agrammatic, 15 semantic, and 15 unclassifiable/mixed) and 60 cognitively healthy controls. Participants completed sentence comprehension and production tasks with systematically manipulated syntactic features. Item-level linguistic determinants were examined using ridge regression, diagnostic performance using receiver operating characteristic analyses, and neuroanatomical correlates using voxel-based morphometry of structural MRI. Performance on sentence comprehension and production was influenced by grammatical and lexical features. Subject-relative clauses, passive constructions, a higher proportion of function words, longer character length, and greater lexical content were associated with poorer performance among participants with PPA. Sentence comprehension was impaired in the logopenic, nonfluent/agrammatic, and semantic variants, even when isolated to the syntactic component of the sentence comprehension task. Similarly, sentence production was impaired across all PPA variants (all P < 0.01 versus controls). No significant differences were observed among PPA variants. Adjusted receiver operating characteristic analyses demonstrated high discrimination between each PPA variant and controls, with areas under the curve ranging from 0.87 to 0.97 for sentence comprehension-syntax and from 0.91 to 0.97 for sentence production. However, pairwise comparisons showed no significant differences in discriminative performance among PPA variants after correction for multiple comparisons. Both sentence comprehension-syntax and sentence production showed associations with semantic and repetition measures in addition to motor speech measures. Voxel-based morphometry showed that higher sentence comprehension-syntax scores were associated with greater grey matter volume in left frontotemporal and cingulate regions, whereas higher sentence production scores were additionally associated with greater gray matter volume in frontostriatal structures, including the caudate, putamen, and thalamus. Syntactic processing impairment in Chinese-speaking individuals with PPA extends beyond the nonfluent/agrammatic variant and is associated with distributed frontotemporal and frontostriatal regions, as well as lexical-semantic and auditory verbal short term memory mechanisms. These findings suggest that the cognitive and neural manifestations of syntactic impairment may be shaped by language-specific typological properties, underscoring the need for linguistically informed approaches to the assessment and interpretation of PPA.

Humans routinely encounter speech in languages they have never heard, yet how the brain responds to such input and whether bilingual experience shapes this response remains unknown. Here, we used electroencephalography (EEG) and temporal response function (TRF) modeling to examine cortical tracking of the speech envelope in 24 English-monolingual and 24 English-Mandarin bilingual adults. Participants listened to naturally produced continuous speech in three languages: English (familiar to all), Mandarin (familiar to bilinguals only), and Vietnamese (unfamiliar to all). We report two main findings. First, both monolinguals and bilinguals showed enhanced cortical tracking for unfamiliar relative to familiar languages, evidenced by higher EEG prediction accuracy (PA). Monolinguals showed enhanced tracking for both Mandarin and Vietnamese, whereas bilinguals showed enhancement only for Vietnamese, consistent with Mandarin being a familiar language for this group. This finding suggests that enhanced cortical encoding of unfamiliar speech is a general property of the listening brain, not a signature of listening to a non-native language or reduced language proficiency. Second, bilinguals strikingly showed stronger cortical tracking than monolinguals overall, in both PA and TRF peak weights, with the TRF peak weight advantage present across all three languages, suggesting a difference in how bilingual experience shapes the neural encoding of speech. These findings have implications for understanding how the brain navigates the linguistic diversity of everyday life in an increasingly global, multilingual world.

Older adults typically exhibit reduced episodic memory precision, while maintaining relatively preserved retrieval success. However, little is known about whether these age-related differences are influenced by internal biological factors (e.g., chronotype) or external testing conditions (e.g., experiment format, time of day). To address this question, younger and older adults completed an object-location memory task online, either in the morning or evening, and either with or without video-based supervision. Memory performance was assessed using mean absolute error and Bayesian hierarchical mixture modelling, which dissociated memory precision ({kappa}) from the probability of memory-based responding ({theta}). Immediate memory performance was high across age groups, irrespective of time of day. Greater encoding error predicted greater retrieval error, and participants tested in the video condition exhibited lower recall error and higher recognition performance than those tested without supervision. Consistent with prior studies, older adults exhibited reduced memory precision relative to younger adults, whereas retrieval success remained largely intact. However, Bayesian Hierarchical Modelling provided no evidence that time of day, experiment format, or their interactions with age influenced either memory precision or retrieval probability. Older adults reported stronger morning preferences than younger adults, and participants generally selected testing times that aligned with their chronotype. Nevertheless, alignment between chronotype and testing time did not modulate memory performance. The results indicate that age-related differences in episodic memory precision are robust across variations in testing context, including time of day, experiment format, and individual differences in chronotype. More broadly, the results support the feasibility of remote and unsupervised testing for memory precision research and suggest that chronotype and testing time are unlikely to be major sources of variability in immediate object-location memory performance.

We investigated how auditory and visual presentation of small numerical magnitudes and non- numerical magnitudes are passively processed at the neural level. Earlier research suggests automatic processing of quantities occurs rapidly in the brain. However, there are no studies on passive, pre-attentive change detection of magnitudes utilizing mismatch negativity (MMN) across sensory modalities in same participants, important to understand amodal processing of magnitudes. We recorded EEG in passive auditory and visual multi-feature oddball and control paradigms from the same adult individuals (N=104/105, respectively). In the auditory paradigm, the standard stimulus was a 2-part sound, while the deviant stimuli varied in frequency, intensity, gap length, and number of sounds (1-part and 3-part stimuli). In the visual paradigm, the standard stimulus was a dot array containing two medium-sized dots, while the deviant stimuli varied in numerosity (1 or 3 dots) and dot size (small or large). The results for the auditory paradigm showed significant MMN across all features, including comparisons with deviant-alone control stimuli, except for the 2-part vs. 1-part contrast. The results for the visual paradigm suggested differences in processing across all features apart from large and medium-size stimuli. These results replicate earlier MMN findings that the brain distinguishes pre-attentively changes in sound frequency, amplitude and gap. Auditorily presented small numerical magnitudes also showed pre-attentive processing but less robustly to the contrast 2 vs. 1. Visual pre-attentive processing of small numerical magnitudes was also observed. Together these findings could be interpreted to support the existence of abstract, pre- attentive processing of numerical magnitudes. Highlights* Auditory and visual processing of numerical and non-numerical magnitudes was examined with EEG * Auditory non-numerical magnitudes and medium vs. small dots replicated earlier MMN studies * aMMN and vMMN showed pre-attentive processing of changes in small numerosities 2 vs. 3 and 2 vs. 1 * 2 vs. 1 tone processing was less robust than 2 vs. 3 or the processing of the visual contrasts * The brain processes changes in small non-symbolic magnitudes pre-attentively

Developmental dyslexia is associated with impaired cortical tracking of continuous speech and difficulties in perceiving within-word prosodic structure in children and adults. For adults and continuous speech, both low-frequency delta- and theta-band impairments and high-frequency gamma- and beta-band differences are found. To date, perceptual difficulties with intra-word prosody have not been studied in direct relation to neural speech encoding. Here neurotypical adults and adults with dyslexia listened to multisyllabic words. EEG was recorded, and cortical encoding was quantified using temporal response function (TRF) modelling. Four speech representations were explored: lexical stress pattern (intra-word prosodic prominence), the low-frequency speech envelope, word onsets and syllable onsets. Adults with dyslexia showed significantly reduced encoding of intra-word prosodic prominence (delta band) and of the speech envelope (delta and theta bands). In contrast, encoding of word and syllable onsets was preserved. Pinpointing delta-band cortical tracking as central to encoding intra-word prosodic prominence opens new avenues for research.

Recalling scenes and events depends on how information is relationally organised in memory, but it is unclear whether the organisation of eye movements during encoding, rather than simply how much is explored, shapes what is remembered. Using a scene-viewing paradigm and drawing-based free recall task to capture the content and structure of remembered scenes, we examined whether scene memory was better explained by 'lower-order' measures reflecting the magnitude and spatial extent of sampling, or 'higher-order' measures capturing gaze organisation and temporal dynamics. Relative to lower-order measures (number of fixations and scanpath length), memory precision was better predicted by repeated sampling of viewed regions (refixations) and gaze distributions (stationary gaze entropy) during encoding. Thus, the organisation of visual attention, rather than sampling quantity, contributed to scene representations that preserved relationships between elements. These findings highlight a role for spatial gaze dynamics in optimally encoding organised, relational scene representations for episodic memory.

Neuroimaging studies have identified a specialised social brain network that supports emotion recognition and social cognition. This network performs a range of functions that include facial expression recognition and inferring the mental states of others. Studies of neuropsychological patients report that damage to the right inferior frontal gyrus (IFG), the top-down control area in this network, impairs facial expression recognition. To investigate how transient disruption of the right IFG affects the wider social brain we combined transcranial magnetic stimulation (TMS) with functional magnetic resonance imaging (fMRI). Participants (n=20) were scanned across two sessions while performing a delayed match-to-sample emotion recognition task in which happy or fearful expressions were preceded by a congruent or incongruent word cue. Prior to each scan, thetaburst TMS was delivered over the right IFG or over the vertex control site (session order was balanced across participants). A group whole-brain analysis revealed that TMS to the IFG increased neural activity in multiple regions of the social brain network. These included the bilateral temporal pole, precuneus and medial prefrontal cortex (mPFC). This pattern of results shows that the disruption of top-down control mechanisms localised in the IFG alters the neural processing in remote nodes of the social brain network. Our findings are discussed within the wider context of how we recognise and understand the emotions of other people.

Task demand has a long-standing history in experimental psychology, with numerous investigations of the capacity of different systems and processes under varying cognitive load. Whilst demand is a broadly used term in the literature, it is limited by a lack of cross-domain operationalisation, and thus can be a confound in many inter-domain investigations. To address this, we generated and validated two large-scale, open-source, widely applicable stimuli sets that: (i) can probe a wide, continuous range of objective behaviourally-measured processing demand, and (ii) can be directly matched across two highly contrastive cognitive domains (semantic and visuospatial processing). We normed these tasks in a large, online cohort of healthy adults, enabling future studies to utilise and benefit from reliable baseline measures of demand. Using a matching algorithm that takes into account both speed and accuracy, we then closely paired each semantic judgement trial with a trial of comparable difficulty from the corresponding visuospatial task to produce a cross domain matched set of over 400 items. Finally, we analysed the psycholinguistic and perceptual properties of these stimuli to explore some of the underlying factors driving demand.

Neuroimaging studies identify the superior temporal sulcus (STS) as an anatomical and functional target in autism spectrum disorder (ASD). Yet, the STS is a heterogeneous structure containing unique subregions, such as the superior temporal asymmetrical pit (STAP), which is a recently identified human-specific landmark. To date, no study has compared the STAP between ASD individuals and neurotypical controls (NTs) in a large sample. Here, we analyzed the mean intra-hemispheric sulcal depth and inter-hemispheric laterality of the STAP, as well as the anterior and posterior portions of the STS (aSTS, pSTS), in 100 NTs and 100 ASD male individuals (ages 5-18) using a discovery-replication design. Across samples, the STAP and pSTS showed rightward asymmetry, while the aSTS showed leftward asymmetry within groups. All features of the STAP, aSTS, or pSTS did not differ significantly between groups. However, pSTS laterality related to individual differences in social cognition, which was further supported by a meta-analysis across over 200 studies showing that neurocognitive functional differences associated with social cognition and ASD are restricted to portions of the STS outside of the STAP. Together, these findings provide fine-grained insight into prior studies showing coarse morphological differences of the STS between individuals with ASD and NTs, as well as open up new questions and new neuroanatomical targets of the heterogeneous STS in future studies of brain structure, brain function, and cognition in ASD, as well as other neurodevelopmental disorders targeting the superior temporal cortex.

Face familiarity elicits reliable neural signatures during perception, yet how it is represented when faces are recalled from memory by using visual imagery and how these signals relate to perceptual representations, remains unclear. We combined perceptual and imagery conditions with electroencephalography and multivariate pattern analysis. In a perceptual session we presented of four famous individuals, while in the imagery session we used a cued recall paradigm and presented abstract symbols, associated to them. By using time-resolved multivariate decoding we tested if familiarity information is shared across stimulus categories, and if perceptual face familiarity representations overlap with processing during cued recall, related to imagery. The face perception condition showed typical and robust familiarity information over occipito-temporal electrodes. The symbolic cues also carried similar familiarity information, demonstrating cross-category familiarity processing between symbols and faces. During cued recall, familiarity information emerged over posterior regions and evolved into a prolonged and late information component over right anterior electrodes. Importantly, cross-domain temporal generalization analysis revealed an overlap between perceptual face familiarity patterns and recall/imagery related processing: perceptual face familiarity information mapped onto later processing during cued recall, with a pronounced and prolonged right anterior dominance and a shorter overlap over left posterior channels. Together, these results suggest that familiarity processing, similarly to category representations, is supported by overlapping neural patterns across perception and recall/imagery, transitioning from dynamic posterior representations, consistent with perceptual analysis, to a stable and prolonged representation over right anterior sites, that is compatible with a sustained processing, related to recall and/or imagery.

Working memory (WM) and decision-making (DM) are closely linked cognitive processes that rely on frontoparietal regions, yet their distinct and shared neural dynamics remain unclear. Using intracranial EEG recordings from 24 human subjects performing a delayed match-to-sample task, we examined high-frequency broadband (HFB) activity to dissociate WM- and DM-related processes with high spatiotemporal resolution. Principal component analysis of frontoparietal HFB activity revealed multiple temporally distinct patterns spanning stimulus presentation and delay phases. The most dominant component reflected sustained WM-related activity across task phases, consistent with persistent maintenance of internal representations. Additional components captured transient WM encoding across trial phases, as well as both stimulus-linked and ramping DM-related activity suggesting dual early and late stages of evaluative processing. These processes were distributed across frontoparietal regions but showed systematic differences in anatomical focus, with WM-related activity concentrated in dorsolateral prefrontal cortex (PFC) and DM-related activity concentrated in ventrolateral PFC, while inferior parietal cortex preferentially tracked the behavioral significance of incoming stimuli and superior parietal cortex tracked the appearance of new information that may require updating ongoing processing. Together, these findings demonstrate that WM and DM processes are separable yet interleaved over time within distributed cortical networks, revealing coordinated but functionally distinct contributions to goal-directed behavior.

Attention prioritizes relevant information from the environment, but does not do so consistently over time. Instead, we sometimes experience poor attentional states which are characterized by a higher degree of performance failures, or "lapses." The source of these lapses--whether they arise from attentional disengagement, failures of attentional selection, or simply failures of response control--is not clear. This study tests whether the strength of neural representations differs as a function of both attentional selection and modulation over time. We recorded electroencephalography (EEG) data while participants performed a sustained attention task requiring the selection of task-relevant items and withholding of responses to rare targets. Results show that relevant items receive prioritized processing in brain signals, as measured with EEG decoding. Yet, their neural representational fidelity weakens under poor sustained attentional states, foreshadowing upcoming behavioral failures. These findings support a neural basis of disengagement during poor attentional states, suggesting that lapses may arise from a decoupling of brain activity from task processing. Finally, pre-item representational strength predicted memory success for targets, suggesting that neural fidelity indexes an encoding-ready state. Results suggest that the quality of neural representations is affected by ongoing attention and plays a key role in processing and memory.

Reading behaviour is sensitive to contextual demands. For example, when reading to study or answer questions, readers strategically allocate more attention to goal-relevant sections, read slower, and regress more frequently to extract specific information based on task demands. This suggests that readers flexibly adapt their strategies according to goals and situational constraints. However, the neurocognitive mechanisms supporting this flexibility remain unclear. To test this, we combined eye-tracking with EEG during naturalistic reading and examined how short-term reading goals modulated the neural tracking of hierarchical linguistic features at the orthographic (orthographic neighbourhood size), lexical (word frequency), and contextual-semantic (Surprisal) levels. Forty native English speakers read narratives in three goal conditions: Baseline (no goal), Proofreading (detect spelling errors), and Comprehension (attend to content). Fixation-aligned word-level EEG activity was modelled using multivariate temporal response function to estimate the strength of feature-specific neural tracking. Orthographic tracking was significantly enhanced during Proofreading relative to Baseline, and predicted better Proofreading accuracy. Conversely, stronger frequency tracking predicted better Comprehension accuracy. Contextual-semantic tracking was not modulated by task goal. These findings suggest that reading goals selectively bias neural processing towards linguistic features (sublexical vs. lexical) that support successful task performance, providing evidence for short-term functional plasticity in linguistic processing and supporting a flexible predictive processing account of goal-directed reading.

PurposeDuring speech planning, the brain predicts the auditory consequences of its movements and modulates the auditory system--a process called pre-speech auditory modulation (PSAM). We investigated the link between PSAM and behavioral error correction and determined how aging influences these mechanisms. MethodsSeventeen young adults (18-32 years) and 13 older adults (50-85 years) performed a speaking task involving auditory feedback perturbations and a silent reading control. We measured electrophysiological responses (N1/P2) to auditory probes during speech planning and correlated these modulations with the magnitude of participants subsequent behavioral corrective responses. ResultsBoth groups showed significant modulation of N1 and P2. However, N1 modulation correlated with corrective responses only in young adults. Older adults showed reduced behavioral corrections and smaller, delayed P2 components. Despite these age-related behavioral differences and the loss of the modulation-correction correlation, older adults maintained modulation magnitudes comparable to those of younger adults. ConclusionsN1 modulation serves as a neural index of the brains predictive processes during speech planning. Aging appears to selectively disrupt the integration of these signals into motor output rather than the internal generation of the predictions themselves.

Modest positive associations between episodic memory performance and whole hippocampal and hippocampal subfield volumes have been reported in numerous prior studies. A smaller number of studies have reported associations between hippocampal volume and performance on tests of non-mnemonic cognition. The present study examined whether these associations were evident in a lifespan sample of cognitively healthy adults. Of particular interest was whether any identified associations were sensitive to age, and whether associations between subfield volumes and mnemonic and non-mnemonic performance were subfield dependent. We acquired high-resolution T1- and T2-weighted structural images from 163 adults (18-87 years of age). Participants also undertook a comprehensive neuropsychological test battery and an in-scanner test of source memory. Principal components analysis was employed to reduce the neuropsychological test scores to 5 cognitive components. Two components reflected memory performance while the other three reflected different aspects of non-mnemonic cognition. Hippocampal subfields (Cornu Ammonis (CA)1, CA2-3, dentate gyrus (DG) and subiculum) were segmented and measured with the Automated Segmentation of Hippocampus Subfields (ASHS) package. Source memory performance was selectively associated across participants with CA2-3 volume. By contrast, both mnemonic and non-mnemonic component scores derived from the test battery were associated exclusively with the volume of the DG. All associations were age-invariant. The findings indicate that different cognitive domains can be dissociated by virtue of their associations with different hippocampal subfields. Of importance, these associations appear to be life-long and hence are unlikely to reflect individual differences in age-related decline in structural integrity.

Motor effort has been shown to bias perceptual decisions toward less effortful choices, but it remains unknown whether this bias already takes effect during the early stages of decision formation through preparatory attentional allocation or sensory processing, or during later-stage evidence accumulation preceding response execution. This study investigated when motor effort becomes integrated into decision formation by focusing on the temporal evolution of neural processing during perceptual decision-making. While 64-channel EEG was recorded, twenty-four healthy adults performed an orientation discrimination task in which two Gabor patches appeared simultaneously in the left and right visual hemifield and decisions were reported using two pressure-sensitive response buttons requiring different levels of force. We found that motor effort modulated EEG activity at both the preparatory and later decision stages: pre-stimulus alpha power was reduced over the occipito-parietal cortex contralateral to the low-effort option, and mean centro-parietal positivity (CPP) amplitude preceding response execution was greater over centro-parietal cortex for low-effort choices, while leaving early sensory representations intact as indicated by no differences in P1 or N1 amplitude following stimulus onset. Trial-by-trial CPP amplitude preceding response execution increased with the likelihood of selecting the low-effort option, whereas the pre-stimulus alpha modulation was not associated with behavioral decision bias. These findings suggest that motor effort biases perceptual decisions primarily during later-stage evidence accumulation, thereby providing insight into the neural basis of embodied perceptual decision making.