More than three decades of functional magnetic resonance imaging (fMRI) has gathered extensive evidence of auditory and visual attention effects in the human brain. However, a meta-analysis covering both modalities is lacking. The present activation likelihood estimation (ALE) based meta-analysis reports overlap and segregation of auditory vs. visual attention effects, further dividing those to effects of orienting vs. maintenance of attention, top-down controlled vs. bottom-up triggered attention, and attention to spatial vs. linguistic stimuli. Forty-three eligible auditory and 96 visual studies reporting a total of 1884 activation foci were found with PubMed and Scopus search. ALE meta-analysis revealed multimodal attention-related convergence zones with specific regional specialization in the dorsal and ventral parietal and frontal cortices and supplementary motor area / anterior cingulate cortex. Overall, visual attention was biased towards the dorsal attention network and auditory attention towards the ventral attention network. Midline posterior parietal cortex was associated with spatial attention in both modalities and language-related attention effects in the left inferior frontal and inferior temporal cortices were observed in the audition. In conclusion, the present study showcases the regional topography of attention effects in the brain, identifying brain areas dependent or independent of sensory modality, subprocess of attention, and type of stimulus. The proposed evidence-based multimodal model of attention can be used for interpreting future brain imaging findings as well as clinical observations.

Arvioitu teos: Mikko Salmela: True emotions. Amsterdam/ Philadelphia: John Benjamins, 2014.

Abundant research from early neurocognitive models to recent mega-analyses has highlighted the central role of frontostriatal circuits in attention deficit hyperactivity disorder (ADHD). However, it remains unclear which specific aspects of functionally organized frontostriatal loops are affected by ADHD and how these disruptions differ across individuals in light of the disorder’s marked heterogeneity. We investigated frontostriatal connectivity in individualised circuits in 40 adults with ADHD and 36 neurotypical controls using a multimodal dataset that included diffusion-weighted magnetic resonance imaging (MRI), as well as functional MRI during working memory updating, resting state, and a naturalistic attention task. Compared with neurotypical controls, adults with ADHD exhibited reduced structural connectivity strength and increased mean, axial, and radial diffusivity in tracks originating from medial and orbital prefrontal areas. Functional data revealed weaker connectivity in the ADHD group during verbal and visuospatial working memory tasks in circuits connecting the striatum with the dorsolateral prefrontal cortex, motor regions, and orbitofrontal cortex, while no group differences were found during resting state or the naturalistic task. Structural and functional aberrancies were only partly overlapping. Comparisons with atlas-based analyses highlighted the precision of individualised connectivity mapping. Together, these findings suggest that (1) frontostriatal functional connectivity aberrancies in ADHD are driven by striatum-dependent cognitive processes such as working memory, (2) functional and structural differences are related to partly different frontostriatal circuits, and (3) precise mapping of frontostriatal pathways can be achieved through individualised connectivity mapping.

Background: Working memory (WM) deficits are among the most prominent cognitive impairments in attention deficit hyperactivity disorder (ADHD). While functional connectivity is a prevailing approach in brain imaging of ADHD, alterations in WM-related functional brain networks and their malleability by cognitive training are not well known. We examined whole-brain functional connectivity differences between adults with and without ADHD during n-back WM tasks and rest at pretest, as well as the effects of WM training on functional and structural brain connectivity in the ADHD group. Methods: Forty-two adults with ADHD and 36 neurotypical controls performed visuospatial and verbal n-back tasks during functional magnetic resonance imaging (fMRI). In addition, seven-minute resting state fMRI data and diffusion-weighted MR images were collected from all participants. The adults with ADHD continued into a 5-week randomized controlled WM training trial (experimental group training on a dual n-back task, n = 21; active control group training on Bejeweled II video game, n = 21), followed by a posttraining MRI. Brain connectivity was examined with Network-Based Statistic. Results: At the pretest, adults with ADHD had decreased functional connectivity compared with the neurotypical controls during both n-back tasks in networks encompassing fronto-parietal, temporal, occipital, cerebellar, and subcortical brain regions. Furthermore, WM-related connectivity in widespread networks was associated with performance accuracy in a continuous performance test. Regarding resting state connectivity, no group differences or associations with task performance were observed. WM training did not modulate functional or structural connectivity compared with the active controls. Conclusion: Our results indicate large-scale abnormalities in functional brain networks underlying deficits in verbal and visuospatial WM commonly faced in ADHD. Training-induced plasticity in these networks may be limited.

When performing cognitive tasks in noisy conditions, the brain needs to maintain task performance while additionally controlling the processing of task-irrelevant and potentially distracting auditory stimuli. Previous research indicates that a fundamental mechanism by which this control is achieved is the attenuation of task-irrelevant processing, especially in conditions with high task demands. However, it remains unclear whether the processing of complex naturalistic sounds can be modulated as easily as that of simpler ones. To address this issue, the present fMRI study examined whether activity related to task-irrelevant meaningful speech is attenuated similarly as that related to meaningless control sounds (nonsense speech and noise-vocoded, unintelligible sounds). The sounds were presented concurrently with three numerical tasks varying in difficulty: an easy control task requiring no calculation, a 'routine' arithmetic calculation task and a more demanding 'creative' arithmetic task, where solutions are generated to reach a given answer. Consistent with their differing difficulty, the tasks activated fronto-parieto-temporal regions parametrically (creative > routine > control). In bilateral auditory regions, activity related to the speech stimuli decreased as task demands increased. Importantly, however, the attenuation was more pronounced for meaningful than nonsense speech, demonstrating that distractor type can strongly modulate the extent of the attenuation. This also suggests that semantic processing may be especially susceptible to attenuation under conditions with increased task demands. Finally, as this is the first study to utilize the 'creative' arithmetic task, we conducted exploratory analyses to examine its potential in assessing neural processes involved in mathematical problem-solving beyond routine arithmetic.

Selective attention-related top-down modulation plays a significant role in separating relevant speech from irrelevant background speech when vocal attributes separating concurrent speakers are small and continuously evolving. Electrophysiological studies have shown that such top-down modulation enhances neural tracking of attended speech. Yet, the specific cortical regions involved remain unclear due to the limited spatial resolution of most electrophysiological techniques. To overcome such limitations, we collected both electroencephalography (EEG) (high temporal resolution) and functional magnetic resonance imaging (fMRI) (high spatial resolution), while human participants selectively attended to speakers in audiovisual scenes containing overlapping cocktail party speech. To utilise the advantages of the respective techniques, we analysed neural tracking of speech using the EEG data and performed representational dissimilarity-based EEG-fMRI fusion. We observed that attention enhanced neural tracking and modulated EEG correlates throughout the latencies studied. Further, attention-related enhancement of neural tracking fluctuated in predictable temporal profiles. We discuss how such temporal dynamics could arise from a combination of interactions between attention and prediction as well as plastic properties of the auditory cortex. EEG-fMRI fusion revealed attention-related iterative feedforward-feedback loops between hierarchically organised nodes of the ventral auditory object related processing stream. Our findings support models where attention facilitates dynamic neural changes in the auditory cortex, ultimately aiding discrimination of relevant sounds from irrelevant ones while conserving neural resources.

Reading skills and developmental dyslexia, characterized by difficulties in developing reading skills, have been associated with brain anomalies within the language network. Genetic factors contribute to developmental dyslexia risk, but the mechanisms by which these genes influence reading skills remain unclear. In this preregistered study (https://osf.io/7sehx), we explored if developmental dyslexia susceptibility genes DNAAF4, DCDC2, NRSN1, and KIAA0319 are associated with brain function in fluently reading adolescents and young adults. Functional MRI and task performance data were collected during tasks involving written and spoken sentence processing, and DNA sequence variants of developmental dyslexia susceptibility genes previously associated with brain structure anomalies were genotyped. The results revealed that variation in DNAAF4, DCDC2, and NRSN1 is associated with brain activity in key language regions: the left inferior frontal gyrus, middle temporal gyrus, and intraparietal sulcus. Furthermore, NRSN1 was associated with task performance, but KIAA0319 did not yield any significant associations. Our findings suggest that individuals with a genetic predisposition to developmental dyslexia may partly employ compensatory neural and behavioral mechanisms to maintain typical task performance. Our study highlights the relevance of these developmental dyslexia susceptibility genes in language-related brain function, even in individuals without developmental dyslexia, providing valuable insights into the genetic factors influencing language processing.

Human listeners prefer octave intervals slightly above the exact 2:1 frequency ratio. To study the neural underpinnings of this subjective preference, called the octave enlargement phenomenon, we compared neural responses between exact, slightly enlarged, oversized, and compressed octaves (or their multiples). The first experiment (n = 20) focused on the N1 and P2 event-related potentials (ERPs) elicited in EEG 50-250 ms after the second tone onset during passive listening of one-octave intervals. In the second experiment (n = 20) applying four-octave intervals, musician participants actively rated the different octave types as 'low', 'good' and 'high'. The preferred slightly enlarged octave was individually determined prior to the second experiment. In both experiments, N1-P2 peak-to-peak amplitudes attenuated for the exact and slightly enlarged octave intervals compared with compressed and oversized intervals, suggesting overlapping neural representations of tones an octave (or its multiples) apart. While there were no differences between the N1-P2 amplitudes to the exact and preferred enlarged octaves, ERP amplitudes differed after 500 ms from onset of the second tone of the pair. In the multivariate pattern analysis (MVPA) of the second experiment, the different octave types were distinguishable (spatial classification across electroencephalography [EEG] channels) 200 ms after second tone onset. Temporal classification within channels suggested two separate discrimination processes peaking around 300 and 700 ms. These findings appear to be related to active listening, as no multivariate results were found in the first, passive listening experiment. The present results suggest that the subjectively preferred octave size is resolved at the late stages of auditory processing.

Electrophysiological studies show that top-down modulation enhances neural tracking of attended speech in environments with overlapping speech. Yet, the specific cortical regions involved remain unclear due to the limited spatial resolution of most electrophysiological techniques. Therefore, we performed speech envelope reconstruction and representational dissimilarity-based EEG-fMRI fusion (using temporal response function estimated from EEG, n = 19, and fMRI, n = 19) to determine the spatiotemporal dynamics of attention to audiovisual cocktail-party speech. Attention related enhancement of neural tracking fluctuated in predictable temporal profiles. Such temporal dynamics may arise due to interactions between attention and prediction or other plastic mechanisms in the auditory cortex, or both. EEG-fMRI fusion revealed attention-related recurrent feedforward-feedback loops in the ventral processing stream. Our findings support models where attention facilitates dynamic neural changes in the auditory cortex, ultimately aiding discrimination of relevant sounds from irrelevant ones using minimal neural resources.

EEG data for octave enlargement experiment used in the EJN article. File naming examples: S8E1C = Subject 8, Experiment 1, Complex tone adapter S8E1S = Subject 8, Experiment 1, Sinusoidal tone adapter S8E2 = Subject 8, Experiment 2 All files in one-file EEGLAB format (EEGLAB 2022.1)

While the previous fMRI studies suggest that the contents of the visual working memory (VWM) are represented in a spatially widely distributed brain network and the previous EEG studies have revealed some temporal properties of the memory processes, the exact spatio-temporal dynamics of working memory processes are not yet understood.Here we used multivariate EEG-fMRI fusion analysis to combine spatially (fMRI) and temporally (EEG) precise information, separately measured (n = 29) during a cued and delayed orientation change detection.Representational dissimilarity matrices (RDMs) from EEG responses in 10 ms time bins and fMRI responses from 360 different brain regions were correlated with each other as well as with model RDMs.Both EEG and fMRI response patterns were almost fully explained by attention (left/right cue) and only minimally by memory (set size and change magnitude).EEG-fMRI fusion showed distinct temporal profiles in different regions containing sustained information and transient peaks.The results highlight the role of attentional processes during working memory tasks.

Selective attention related top-down modulation plays a significant role in separating relevant speech from irrelevant background speech when vocal attributes separating concurrent speakers are small and continuously evolving. Electrophysiological studies have shown that such top-down modulation enhances neural tracking of attended speech. Yet, the specific cortical regions involved remain unclear due to the limited spatial resolution of most electrophysiological techniques. To overcome such limitations, we collected both EEG (high temporal resolution) and fMRI (high spatial resolution), while human participants selectively attended to speakers in audiovisual scenes containing overlapping cocktail party speech. To utilize the advantages of the respective techniques, we analysed neural tracking of speech using the EEG data and performed representational dissimilarity-based EEG-fMRI fusion. We observed that attention enhanced neural tracking and modulated EEG correlates throughout the latencies studied. Further, attention related enhancement of neural tracking fluctuated in predictable temporal profiles. We discuss how such temporal dynamics could arise from a combination of interactions between attention and prediction as well as plastic properties of the auditory cortex. EEG-fMRI fusion revealed attention related iterative feedforward-feedback loops between hierarchically organised nodes of the ventral auditory object related processing stream. Our findings support models where attention facilitates dynamic neural changes in the auditory cortex, ultimately aiding discrimination of relevant sounds from irrelevant ones while conserving neural resources.### Competing Interest StatementThe authors have declared no competing interest.

Human language units are hierarchical, and reading acquisition involves integrating multisensory information (typically from auditory and visual modalities) to access meaning. However, it is unclear how the brain processes and integrates language information at different linguistic units (words, phrases, and sentences) provided simultaneously in auditory and visual modalities. To address the issue, we presented participants with sequences of short Chinese sentences through auditory, visual, or combined audio-visual modalities while electroencephalographic responses were recorded. With a frequency tagging approach, we analyzed the neural representations of basic linguistic units (i.e. characters/monosyllabic words) and higher-level linguistic structures (i.e. phrases and sentences) across the 3 modalities separately. We found that audio-visual integration occurs in all linguistic units, and the brain areas involved in the integration varied across different linguistic levels. In particular, the integration of sentences activated the local left prefrontal area. Therefore, we used continuous theta-burst stimulation to verify that the left prefrontal cortex plays a vital role in the audio-visual integration of sentence information. Our findings suggest the advantage of bimodal language comprehension at hierarchical stages in language-related information processing and provide evidence for the causal role of the left prefrontal regions in processing information of audio-visual sentences.

Current knowledge of white matter changes in large-scale brain networks in adult attention deficit hyperactivity disorder (ADHD) is scarce. We collected diffusion-weighted magnetic resonance imaging data in 40 adults with ADHD and 36 neurotypical controls and used constrained spherical deconvolution based tractography to reconstruct whole-brain structural connectivity networks. We used network-based statistic (NBS) and graph theoretical analysis to investigate differences in these networks between the ADHD and control groups, as well as associations between structural connectivity and ADHD symptoms assessed with the Adult ADHD Self-Report Scale or performance in the Conners Continuous Performance Test 2 (CPT-2). NBS revealed decreased connectivity in the ADHD group compared to the neurotypical controls in widespread unilateral networks, which included subcortical and corticocortical structures and encompassed dorsal and ventral attention networks and visual and somatomotor systems. Furthermore, hypoconnectivity in a predominantly left-frontal network was associated with higher amount of commission errors in CPT-2. Graph theoretical analysis did not reveal topological differences between the groups or associations between topological properties and ADHD symptoms or task performance. Our results suggest that abnormal structural wiring of the brain in adult ADHD is manifested as widespread intrahemispheric hypoconnectivity in networks previously associated with ADHD in functional neuroimaging studies.