Imaging neuroscience (Cambridge, Mass.)最新文献

{"title":"Acetaminophen affects the duration but not the occurrence of BOLD signal decline in the dorsal hippocampus after induction of neuronal afterdischarges.","authors":"Alberto Arboit, Karla Krautwald, Frank Angenstein","doi":"10.1162/IMAG.a.161","DOIUrl":"10.1162/IMAG.a.161","url":null,"abstract":"<p><p>Combined in vivo electrophysiological and functional magnetic resonance imaging (fMRI) measurements were used to monitor neuronal and hemodynamic responses in the right dorsal hippocampus during and after electrical stimulation of the right perforant pathway with a short period of 20 Hz pulses. These measurements were performed under two conditions: 1.5% isoflurane (which has a long-term vasodilator effect) or 100 µg/kg medetomidine (which has a long-term vasoconstrictor effect). The stimulation elicited a short period of neuronal afterdischarges (nAD) followed by a sustained decline in fMRI BOLD signals, as previously described (Arboit et al., 2024). While the duration of nAD was similar in presence of isoflurane and medetomidine, the subsequent decline of BOLD signal was significantly longer with isoflurane than with medetomidine. However, when the same experiments were performed in the presence of acetaminophen, the duration of the sustained decline of BOLD signals became similar: acetaminophen significantly prolonged the decline in the presence of medetomidine, whereas it only slightly shortened it in the presence of isoflurane. As acetaminophen did not affect the generation and intensity of nAD, the results indicate that nAD activates at least two different neurovascular coupling (NVC) mechanisms that mediate the sustained BOLD signal decline, of which acetaminophen affects the maintenance.</p>","PeriodicalId":73341,"journal":{"name":"Imaging neuroscience (Cambridge, Mass.)","volume":"3 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12455054/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145139731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mapping individual differences in intermodal coupling in neurodevelopment.","authors":"Ruyi Pan, Sarah M Weinstein, Danni Tu, Fengling Hu, Büşra Tanrıverdi, Rongqian Zhang, Simon N Vandekar, Erica B Baller, Ruben C Gur, Raquel E Gur, Aaron F Alexander-Bloch, Theodore D Satterthwaite, Jun Young Park","doi":"10.1162/IMAG.a.156","DOIUrl":"10.1162/IMAG.a.156","url":null,"abstract":"<p><p>Within-individual coupling between measures of brain structure and function evolves in development and may underlie differential risk for neuropsychiatric disorders. Despite increasing interest in the development of structure-function relationships, rigorous methods to quantify and test individual differences in coupling remain nascent. In this article, we explore and address gaps in approaches for testing and spatially localizing individual differences in intermodal coupling, including a new method, called CEIDR (<b>C</b>luster <b>E</b>nhancement for testing <b>I</b>ndividual <b>D</b>ifferences in <math><mi>ρ</mi></math> (<b>r</b>)). CEIDR controls false positives in individual differences in intermodal correlations that arise from mean and variance heterogeneity and improves statistical power by adopting adaptive cluster enhancement. Through a comparison across different approaches to testing individual differences in intermodal coupling, we delineate subtle differences in the hypotheses they test, which may ultimately lead researchers to arrive at different results. Finally, we illustrate these differences in two applications to brain development using data from the Philadelphia Neurodevelopmental Cohort.</p>","PeriodicalId":73341,"journal":{"name":"Imaging neuroscience (Cambridge, Mass.)","volume":"3 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12455055/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145139378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Functional MRI reveals subcortical auditory push-pull interactions requiring intercollicular integrity.","authors":"Frederico Severo, Mafalda Valente, Noam Shemesh","doi":"10.1162/IMAG.a.155","DOIUrl":"10.1162/IMAG.a.155","url":null,"abstract":"<p><p>The role of subcortical structures in binaural integration is of great interest for auditory processing. The inferior colliculus (IC) is the main auditory midbrain center where ascending and descending auditory projections converge, which was suggested to encode auditory information via a push-pull mechanism (a coordinated antagonistic neural mechanism for adaptive response control) between the two ICs. However, the origin of this push-pull mechanism in the brain and how it interacts with other upstream/downstream subcortical areas are still a matter of great debate. Here, we harness functional MRI (fMRI) in combination with IC lesions in the rat to dissect the push-pull interaction from a pathway-wide perspective. We find evidence for the push-pull mechanism in IC through opposing negative/positive fMRI signals in the ipsilateral/contralateral ICs upon monaural stimulation. By unilaterally lesioning the corresponding contralateral IC, we demonstrate the necessity of collicular integrity and intercollicular interactions for the push-pull interaction. Using binaural stimulation and IC lesions, we show that the push-pull interaction is exerted also in binaural processing. Finally, we demonstrate that, at least at the population level revealed by fMRI, the main push-pull interactions occur first at the IC level, and not earlier, and that the outcome of the push-pull \"calculation\" is relayed downstream to the medial geniculate body (MGB). This dissection of the push-pull interaction sheds light into subcortical auditory function.</p>","PeriodicalId":73341,"journal":{"name":"Imaging neuroscience (Cambridge, Mass.)","volume":"3 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12455056/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145139000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Activation mapping in multi-center retrospective rat sensory-evoked functional MRI datasets using a unified pipeline.","authors":"Marie E Galteau, Margaret Broadwater, Yi Chen, Gabriel Desrosiers-Gregoire, Rita Gil, Johannes Kaesser, Eugene Kim, Pervin Kıryağdı, Henriette Lambers, Yanyan Y Liu, Xavier López-Gil, Eilidh MacNicol, Parastoo Mohebkhodaei, Ricardo X N De Oliveira, Carolina A Pereira, Henning M Reimann, Alejandro Rivera-Olvera, Erwan Selingue, Nikoloz Sirmpilatze, Sandra Strobelt, Akira Sumiyoshi, Channelle Tham, Raul Tudela, Roël M Vrooman, Isabel Wank, Yongzhi Zhang, Wessel A van Engelenburg, Jürgen Baudewig, Susann Boretius, Diana Cash, M Mallar Chakravarty, Kai-Hsiang Chuang, Luisa Ciobanu, Gabriel A Devenyi, Cornelius Faber, Andreas Hess, Judith R Homberg, Ileana O Jelescu, Carles Justicia, Ryuta Kawashima, Thoralf Niendorf, Tom W J Scheenen, Noam Shemesh, Guadalupe Soria, Nick Todd, Lydia Wachsmuth, Xin Yu, Baogui B Zhang, Yen-Yu Ian Shih, Sung-Ho Lee, Joanes Grandjean","doi":"10.1162/IMAG.a.157","DOIUrl":"10.1162/IMAG.a.157","url":null,"abstract":"<p><p>Functional Magnetic Resonance Imaging (fMRI) in rodents is pivotal for understanding the mechanisms underlying Blood Oxygen Level-Dependent (BOLD) signals and phenotyping animal models of disorders, among other applications. Despite its growing use, comparing rodent fMRI results across different research sites remains challenging due to variations in experimental protocols. Here, we aggregated and analyzed 22 sensory-evoked rat fMRI datasets from 12 imaging centers, totaling scans from 220 rats, to get a snapshot of the current acquisitions in the field. This retrospective analysis highlights common practices and parameters to inform future cross-laboratory standardization efforts. We applied a standardized preprocessing pipeline and evaluated the impact of different hemodynamic response function models on group- and individual-level activity patterns. Our analysis revealed inter-dataset variability attributed to differences in experimental design, anesthesia protocols, and imaging parameters. We identified robust activation clusters in all (22/22) datasets. The comparison between stock human models implemented in software and rat-specific models showed significant variations in the resulting statistical maps. Our findings emphasize the necessity for standardized protocols and collaborative efforts to improve the reproducibility and reliability of rodent fMRI studies. We provide open access to all datasets and analysis code to foster transparency and further research in the field.</p>","PeriodicalId":73341,"journal":{"name":"Imaging neuroscience (Cambridge, Mass.)","volume":"3 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12455057/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145139824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mapping brain function underlying naturalistic motor observation and imitation using high-density diffuse optical tomography.","authors":"Dalin Yang, Tessa G George, Chloe M Sobolewski, Sophia R McMorrow, Carolina Pacheco, Kelsey T King, Rebecca Rochowiak, Evan Daniels-Day, Sung Min Park, Emma Speh, Ari Segel, Deana Crocetti, Alice D Sperry, Mary Beth Nebel, Bahar Tunçgenç, Rene Vidal, Natasha Marrus, Stewart H Mostofsky, Adam T Eggebrecht","doi":"10.1162/IMAG.a.153","DOIUrl":"10.1162/IMAG.a.153","url":null,"abstract":"<p><p>Autism spectrum disorder (ASD), a condition defined by deficits in social communication, restricted interests, and repetitive behaviors, is associated with early impairments in motor imitation that persist through childhood and into adulthood. Alterations in the mirror neuron system (MNS), crucial for interpreting and imitating actions, may underlie these ASD-associated differences in motor imitation. High-density diffuse optical tomography (HD-DOT) overcomes logistical challenges of functional magnetic resonance imaging to enable identification of neural substrates of naturalistic motor imitation. We aim to investigate brain function underlying motor observation and imitation in autistic and non-autistic adults. We hypothesize that HD-DOT will reveal greater activation in regions associated with the MNS during motor imitation than during motor observation, and that MNS activity will negatively correlate with autistic traits and motor fidelity. We imaged brain function using HD-DOT in N = 100 participants (19 ASD and 81 non-autistic individuals) as they engaged in observing or imitating a sequence of arm movements. Additionally, during imitation, participant movements were simultaneously recorded with 3D cameras for computerized assessment of motor imitation (CAMI). Cortical responses were estimated using general linear models, and multiple regression was used to test for associations with autistic traits, assessed via the Social Responsiveness Scale-2 (SRS-2), and imitation fidelity, assessed via CAMI. Both observing and imitating motor movements elicited significant activations in higher-order visual and MNS regions, including the inferior parietal lobule, superior temporal gyrus, and inferior frontal gyrus. Imitation additionally exhibited greater activation in the superior parietal lobule, primary motor cortex, and supplementary motor area. Notably, the right temporal-parietal junction exhibited activation during observation but not during imitation. Higher presence of autistic traits was associated with increased activation during motor observation in the right superior parietal lobule. No significant associations between brain activation and CAMI scores were observed. Our findings provide robust evidence of shared and task-specific cortical responses underlying motor observation and imitation, emphasizing the differential engagement of MNS regions during motor observation and imitation.</p>","PeriodicalId":73341,"journal":{"name":"Imaging neuroscience (Cambridge, Mass.)","volume":"3 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12451301/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145132934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Task-related changes in aperiodic activity are related to visual working memory capacity independent of event-related potentials and alpha oscillations.","authors":"Sian Virtue-Griffiths, Alex Fornito, Sarah C H Thompson, Mana Biabani, Jeggan Tiego, Tribikram Thapa, Neil W Bailey, Nigel C Rogasch","doi":"10.1162/IMAG.a.150","DOIUrl":"10.1162/IMAG.a.150","url":null,"abstract":"<p><p>Research using electroencephalography (EEG) has shown that individual differences in visual working memory capacity are related to slow-wave event-related potentials (ERPs) and suppression of alpha-band oscillatory power during the delay period of memory tasks. However, recent evidence suggests that changes in non-oscillatory (aperiodic) features of the EEG signal are related to working memory performance. We assessed several features of task-related changes in aperiodic activity including its spatial distribution, the effect of memory load, and the relationships between aperiodic activity, memory capacity, slow-wave ERPs, and alpha suppression. Eighty-four healthy individuals performed a continuous recall working memory (WM) task consisting of 2, 4 or 6 coloured squares while EEG was recorded. Aperiodic activity during a baseline and WM delay period was quantified by fitting a model to the background of the EEG power spectra, which returned parameters describing the slope (exponent) and broadband offset of the spectra. The aperiodic exponent increased (i.e., slope steepened) in fronto-central electrodes during the WM delay period, whereas the offset decreased over parieto-occipital electrodes. These task-related changes in aperiodic activity did not differ between memory loads. Larger increases in the aperiodic exponent were associated with higher working memory capacity measured from both the WM task and a separate battery of complex span tasks, a relationship that was independent of slow-wave ERPs and alpha suppression. Our findings suggest that WM task-related changes in aperiodic activity are region specific and reflect an independent neural mechanism that is important for general working memory ability.</p>","PeriodicalId":73341,"journal":{"name":"Imaging neuroscience (Cambridge, Mass.)","volume":"3 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12451300/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145132939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multimodal evidence challenges the effectiveness of probabilistic cueing for establishing sensory expectations.","authors":"Ziyue Hu, Dominic M D Tran, Reuben Rideaux","doi":"10.1162/IMAG.a.152","DOIUrl":"10.1162/IMAG.a.152","url":null,"abstract":"<p><p>Predictive coding theories posit a reduction in error-signaling neural activity when incoming sensory input matches existing expectations-a phenomenon termed <i>expectation suppression</i>. However, the empirical evidence for expectation suppression, as well as its underlying neural mechanism, is contentious. A further aspect of predictive coding that remains untested is how predictions are integrated across sensorimotor domains. To investigate these two questions, we employed a novel cross-domain probabilistic cueing paradigm, where participants were presented with both visual and motor cues within a single trial. These cues manipulated the orientation and temporal expectancy of target stimuli with 75% validity. Participants completed a reproduction task where they rotated a bar to match the orientation of the target stimulus while their neural and pupil responses were respectively measured via electroencephalography and eye tracking. Our results showed a consistent, feature-unspecific effect of motor expectancy across multiple measures, while evidence for visual expectancy was limited. However, neither motor nor visual expectancy modulated the fidelity of sensory representations. These results indicate that violations of temporal expectancy in the current study may reveal the brain's intrinsic sensitivity to temporal regularities in the natural settings, rather than feature-specific predictions. In contrast, the absence of visual expectancy effects in both neural and pupillometry results adds to a growing body of evidence questioning the effectiveness of probabilistic cueing paradigms for establishing expectations capable of altering sensory representations. Due to null findings in the visual and sensory representation analyses, we did not further investigate cross-domain prediction integration.</p>","PeriodicalId":73341,"journal":{"name":"Imaging neuroscience (Cambridge, Mass.)","volume":"3 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12441825/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145088297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of high-frequency ultrasound transducers for microvascular localization microscopy in the mouse brain.","authors":"Matthew R Lowerison, Yike Wang, Bing-Ze Lin, Zhe Huang, Dongliang Yan, YiRang Shin, Pengfei Song","doi":"10.1162/IMAG.a.151","DOIUrl":"10.1162/IMAG.a.151","url":null,"abstract":"<p><p>Ultrasound localization microscopy is a super-resolution vascular imaging technique which has garnered substantial interest as a tool for small animal neuroimaging, neuroscience research, and the characterization of vascular pathologies. In the context of small animal neurovascular imaging, we posit that increasing the ultrasound imaging frequency is a straightforward approach to enable higher concentrations of microbubble contrast agents, thus increasing the likelihood of microvascular mapping and decreasing the imaging duration. To test this hypothesis, we compared ULM imaging resolution of mouse brain vasculature for three transducers with different center transmit frequencies (15 MHz, 23 MHz, and 31 MHz) under conditions of low and high MB concentration. We demonstrate that higher frequency imaging resulted in more efficient microbubble localization due to a smaller microbubble point-spread function that is easier to localize, and which can achieve a higher localizable concentration within the same unit volume of tissue. We found that increasing the imaging frequency had a minor impact on ULM spatial resolution, as measured by Fourier ring correlation, under the low MB concentration case, but a substantial impact in the high MB concentration case. High-frequency ULM yielded a spatial resolution of 6.9 μm, as measured by Fourier ring correlation, throughout the entire depth of the brain. This highlights the potential of this technology as a highly relevant tool for neuroimaging research, which has substantial implications for neuroscientists investigating microvascular function in disease states, regulation, and brain development.</p>","PeriodicalId":73341,"journal":{"name":"Imaging neuroscience (Cambridge, Mass.)","volume":"3 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12437603/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145082574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Supramodal and modality-specific neural information supports multi-feature prediction errors across cortical levels.","authors":"Maria Niedernhuber, Francesca Fardo, Micah Allen, Tristan Bekinschtein","doi":"10.1162/IMAG.a.149","DOIUrl":"10.1162/IMAG.a.149","url":null,"abstract":"<p><p>Predictive coding posits that the brain actively anticipates inputs from different senses, generating prediction errors when incoming information deviates from internal expectations. While much research has focused on prediction errors elicited by violations of single sensory features, natural environments frequently present more complex events deviating across multiple stimulus dimensions and sensory modalities. In this study, we employed a hierarchical oddball paradigm (n = 30) manipulating auditory and somatosensory stimuli to violate one or two sensory features while high-density EEG was recorded. Temporal decoding revealed that while both single- and double-deviants evoked sustained supramodal activation patterns, double-deviants uniquely elicited a supramodal response starting at 100 ms after the oddball. Effective connectivity analyses identified shared interhemispheric interactions between inferior frontal gyri across modalities, as well as distinct modality-specific connectivity within early and associative sensory cortices. Our findings demonstrate that multi-feature prediction errors recruit both rapid supramodal integration mechanisms and hierarchically organized modality-specific pathways. These results advance our understanding of how the brain flexibly integrates multiple sensory expectation violations across different levels of cortical processing, providing new insights into the neural architecture supporting predictive perception.</p>","PeriodicalId":73341,"journal":{"name":"Imaging neuroscience (Cambridge, Mass.)","volume":"3 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12437609/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145082561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Visual stimulus-evoked blood velocity responses in individual human posterior cerebral arteries measured with dynamic phase-contrast functional MR angiography.","authors":"Zhangxuan Hu, Sébastien Proulx, Grant A Hartung, Daniel E P Gomez, Jingyuan E Chen, Divya Varadarajan, Elif Gökçal, Saskia Bollmann, Can Ozan Tan, M Edip Gurol, Jonathan R Polimeni","doi":"10.1162/IMAG.a.148","DOIUrl":"10.1162/IMAG.a.148","url":null,"abstract":"<p><p>Functional MRI (fMRI) tracks brain activity through the associated hemodynamic changes via neurovascular coupling. Neurons communicate with the microvessels of the parenchyma to initiate a hemodynamic response, and these microvessels then communicate with upstream arterioles and arteries. The role of the larger feeding arteries-far upstream from the site of neuronal activity-in coordinating this response is incompletely understood, yet is important for the interpretation of fMRI. Functional transcranial Doppler (fTCD) can noninvasively measure blood velocity changes in a subset of the largest macrovessels, albeit with poor spatial resolution, whereas existing functional MR angiography (fMRA) methods can assess blood velocity in mid-sized macrovessels but still lack the temporal resolution required to capture dynamic responses. This study aims to propose a new, quantitative fMRA method for measuring blood velocity responses in individual vessels in humans at high spatiotemporal resolution. A dynamic functional phase-contrast MRA approach was developed to quantify responses evoked by visual stimuli in the \"P2\" segment of the posterior cerebral artery (PCA), located ~6 cm away from primary visual cortex. The achieved temporal resolution is comparable with that of conventional blood-oxygenation-level-dependent (BOLD) fMRI, enabling block-design stimulation paradigms similar to those used in conventional fMRI studies. The temporal and spatial properties of the blood velocity responses were evaluated using both long- and short-duration visual stimuli presented to either the full visual field or a single hemifield. Robust responses were measured on both 3T and 7T clinical MRI scanners, and an approximately 3.3 ± 1.2 cm/s increase in the blood velocity in the targeted segment was observed, which is roughly a 10% increase from baseline. Visual hemifield stimulation generated a measurable blood velocity response only in the contralateral cerebral hemisphere, indicating that systemic physiological changes occurring with stimulation cannot account for the observed response, suggesting that they instead reflect neurovascular coupling initiated in the visual cortex. The observed arterial blood velocity response is consistent with a downstream reduction in microvascular resistance and may represent a passive response rather than an active vessel dilation at the targeted arterial segment. The proposed method has the potential to extend the capability of commonly used approaches, such as fTCD, in clinical applications.</p>","PeriodicalId":73341,"journal":{"name":"Imaging neuroscience (Cambridge, Mass.)","volume":"3 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12434382/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145076154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}