Functional Transcranial Doppler Research Articles

Aberrant cerebral blood flow responses during cognition: Implications for the understanding of cognitive deficits in fibromyalgia.

There is ample evidence for cognitive deficits in fibromyalgia syndrome (FMS). The present study investigated cerebral blood flow responses during arithmetic processing in FMS patients and its relationship with performance. The influence of clinical factors on performance and blood flow responses were also analyzed. Forty-five FMS patients and 32 matched healthy controls completed a mental arithmetic task while cerebral blood flow velocities in the middle (MCA) and anterior (ACA) cerebral arteries were measured bilaterally using functional transcranial Doppler sonography (fTCD). Patients' cognitive processing speeds were slower versus healthy controls. In contrast to patients, healthy controls showed a pronounced early blood flow response (during seconds 4-6 after the warning signal) in all assessed arteries. MCA blood flow modulation during this period was correlated with task performance. This early blood flow response component was markedly less pronounced in FMS patients in both MCAs. Furthermore, patients displayed an aberrant pattern of lateralization, with right hemispheric dominance especially observed in the ACA. Severity of clinical pain in FMS patients was correlated with cognitive performance and cerebral blood flow responses. Cognitive impairment in FMS is associated with alterations in cerebral blood flow responses during cognitive processing. These results suggest a potential physiological pathway through which psychosocial and clinical factors may affect cognition.

Comparing methods for determining motor-hand lateralization based on fTCD signals.

The lateralization index (LI) as determined from functional transcranial Doppler sonography (fTCD) can be used to determine the hemispheric organization of neural activation during a behavioral task. Previous studies have proposed different methods to determine this index, but to our knowledge no studies have compared the performance of these methods. In this study, we compare two established methods with a simpler method proposed here. The aim was to see whether similar results could be achieved with a simpler method and to give an indication of the analysis steps required to determine the LI. A simple unimanual motor task was performed while fTCD was acquired, and the LI determined by each of these methods was compared. In addition, LI determined by each method was related to behavioural output in the form of degree of handedness. The results suggest that although the methods differed in complexity, they yielded similar results when determining the lateralization of motor functions, and its correlation with behavior. Further investigation is needed to expand the conclusions of this preliminary study, however the new method proposed in the paper has great potential as it is much simpler than the more established methods yet yields similar results.

Measuring Neurovascular Coupling by Combining Electroencephalogram and Functional Transcranial Doppler: A Detailed Method

Event Abstract Back to Event Measuring Neurovascular Coupling by Combining Electroencephalogram and Functional Transcranial Doppler: A Detailed Method Lisa Kurylowicz1*, Nicholas Badcock2, Mark Kohler1, Owen Churches3 and Hannah Keage1 1 University of South Australia, Cognitive Neuroscience Laboratory, School of Psychology, Social Work and Social Policy, Australia 2 Macquarie University, ARC Centre of Excellence in Cognition and its Disorders, Department of Cognitive Science, Australia 3 Flinders University, Brain and Cognition Laboratory, School of Psychology, Australia Neuronal function and cerebrovascular supply are usually assessed in isolation however their relationship to each other is critical for brain function. Methods that do exist are typically expensive and unsuitable for populations where the technique would be most valuable, such as the very young and very old. Two groups have previously investigated the relationship between neural function and cerebrovascular supply by pairing electroencephalogram (EEG) and functional transcranial doppler (fTCD). EEG measures neural function via the recording of electrical activity at the scalp, while fTCD uses ultrasound to record blood flow velocity in major cerebral arteries. We furthered previously published methods by improving the data recordings between equipment, data processing methods and the incorporation of active as well as passive visual cognitive tasks. Visual evoked potentials were recorded from the occipital lobe and cerebral blood flow velocity was recorded from the posterior cerebral artery using fTCD while participants completed a passive checkerboard task, along with visual half-field tasks identifying either, tools or symmetrical shapes. We will discuss the design of tasks, particularly given known differences in neural and hemodynamic responses to cognitive operations. Further, we will show how blood flow velocity and event-related potential (ERP; calculated from averaging EEG data) data are correlated and how the degree of correlation changes relative to ERP component and the segment of hemodynamic response (e.g. gain). This combined EEG-fTCD technique - which is non-invasive, not costly and suitable for most populations - stands to make valuable contributions to the understanding of neurovascular coupling in health and disease. Keywords: ERP, Electroencephalogram, hemodynamic response, fTCD, visual half-field, Cerebral blood flow velocity, functional transcranial Doppler, event related potential components Conference: XII International Conference on Cognitive Neuroscience (ICON-XII), Brisbane, Queensland, Australia, 27 Jul - 31 Jul, 2014. Presentation Type: Poster Topic: Methods Development Citation: Kurylowicz L, Badcock N, Kohler M, Churches O and Keage H (2015). Measuring Neurovascular Coupling by Combining Electroencephalogram and Functional Transcranial Doppler: A Detailed Method. Conference Abstract: XII International Conference on Cognitive Neuroscience (ICON-XII). doi: 10.3389/conf.fnhum.2015.217.00305 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 19 Feb 2015; Published Online: 24 Apr 2015. * Correspondence: Miss. Lisa Kurylowicz, University of South Australia, Cognitive Neuroscience Laboratory, School of Psychology, Social Work and Social Policy, Adelaide, Australia, lisa.kurylowicz@unisa.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Lisa Kurylowicz Nicholas Badcock Mark Kohler Owen Churches Hannah Keage Google Lisa Kurylowicz Nicholas Badcock Mark Kohler Owen Churches Hannah Keage Google Scholar Lisa Kurylowicz Nicholas Badcock Mark Kohler Owen Churches Hannah Keage PubMed Lisa Kurylowicz Nicholas Badcock Mark Kohler Owen Churches Hannah Keage Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Measuring cerebral hemodynamic changes during action observation with functional transcranial doppler

[Purpose] The purpose of this study was to investigate the effects of action observation training (AOT) on cerebral hemodynamic changes including cerebral blood flow velocity (CBFV) and cerebral blood flow volume (CBFvol) in healthy subjects. [Subjects] Fifteen healthy subjects participated in this study. [Methods] All subjects were educated regarding AOT, and systolic peak velocity (Vs) as well as mean flow velocity (Vm) in the middle cerebral artery (MCA), anterior cerebral artery (ACA), and posterior cerebral artery (PCA) were evaluated using functional transcranial doppler with a 2-MHz probe, before and after performing AOT. [Results] Healthy subjects showed significant differences in Vs and Vm in the MCA, ACA, and PCA after AOT compared with those before AOT. [Conclusion] Our findings indicate that AOT has a positive effect in terms of an increase in CBFV and CBFvol in healthy subjects, since the brain requires more blood to meet the metabolic demand during AOT.

Hemispheric Specialization for Processing Arithmetic in Adults

Event Abstract Back to Event Hemispheric Specialization for Processing Arithmetic in Adults Veronica Connaughton1*, Vicole Bothma2, Azhani Amiruddin2, Karen Clunies-Ross2, Noel French3 and Allison Fox4 1 Univeristy of Western Australia, School of Psychology, Australia 2 University of Western Australia, Australia 3 King Edward Memorial Hospital, Australia 4 University of Western Australia, School of Psychology, Australia A variety of current models of the cerebral circuits that underpin arithmetic calculation exist although research into cerebral lateralization of mathematical operations is in its initial stages. This study measured middle cerebral artery blood flow lateralization using Functional Transcranial Doppler (fTCD) ultrasonography during the performance of arithmetic tasks to test the triple-code model of numerical functioning. It was hypothesised that blood flow would be greater to the hemisphere responsible for language during multiplication tasks which depend on the retrieval of stored semantic knowledge, whereas bilateral activation would be more likely when adults performed subtraction. Thirteen adults, aged between 18 and 37 years, participated in a one-day cognitive and neuroimaging research program hosted at the Neurocognitive Development Unit. Laterality Indices were obtained whilst they performed an expressive language task and both multiplication and subtraction tasks. Blood flow during the expressive language and numerical calculation tasks showed statistically significant leftward lateralizations and the lateralization indices obtained during the mathematics tasks did not differ significantly from that obtained during the expressive language task (Cohen's d for repeated measures d = 0.160 and d = 0.290 for the multiplication and subtraction tasks, respectively). In partial support of the triple-code model, blood flow while performing multiplication operations was largest over the hemisphere corresponding to language generation. However, contrary to our expectations, blood flow was also significantly lateralised to the left hemisphere while participants performed subtraction. One plausible explanation for these results is that simple subtraction operations similarly draw on the semantic store. It is also possible that the response requirement for both tasks was a confounding factor and future research will attempt to control for this potential confound. Keywords: Arithmetic, subtraction, multiplication, fTCD, middle cerebral artery (MCA), Triple-Code Model Conference: XII International Conference on Cognitive Neuroscience (ICON-XII), Brisbane, Queensland, Australia, 27 Jul - 31 Jul, 2014. Presentation Type: Poster Topic: Cognition and Executive Processes Citation: Connaughton V, Bothma V, Amiruddin A, Clunies-Ross K, French N and Fox A (2015). Hemispheric Specialization for Processing Arithmetic in Adults. Conference Abstract: XII International Conference on Cognitive Neuroscience (ICON-XII). doi: 10.3389/conf.fnhum.2015.217.00128 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 19 Feb 2015; Published Online: 24 Apr 2015. * Correspondence: Ms. Veronica Connaughton, Univeristy of Western Australia, School of Psychology, Perth, Australia, 21104481@STUDENT.UWA.EDU.AU Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Veronica Connaughton Vicole Bothma Azhani Amiruddin Karen Clunies-Ross Noel French Allison Fox Google Veronica Connaughton Vicole Bothma Azhani Amiruddin Karen Clunies-Ross Noel French Allison Fox Google Scholar Veronica Connaughton Vicole Bothma Azhani Amiruddin Karen Clunies-Ross Noel French Allison Fox PubMed Veronica Connaughton Vicole Bothma Azhani Amiruddin Karen Clunies-Ross Noel French Allison Fox Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Effects of noise and mental task performance upon changes in cerebral blood flow parameters.

The objectives of this paper were to determine whether traffic noise influences the parameters of cerebral blood flow (CBF) measured by functional transcranial Doppler sonography (fTCD) during the performance of mental tasks, and to see whether impact of noise on CBF changes with age. The study comprised 36 healthy volunteers, 22 women and 14 men, aged 25-49 years. The fTCD was performed using a fixed 2-MHz probe, aiming for an evaluation of mean velocity (MFV) and the pulsatility index (PI) in the middle cerebral artery (MCA) on both sides. Subsequently, fTCD was monitored: At rest; during performance of the Paced Auditory Serial Addition Test (PASAT); during exposure to traffic noise; and during concomitant exposure to noise and PASAT performance. MFV and PI were compared for particular conditions and correlated with age. During exposure to noise, flow parameters did not change significantly. PASAT performance in silence increased MFV and decreased PI in MCA on both sides. During PASAT performance, on exposure to noise, MCV and PI changed significantly only in the left MCA. However, values of MFV were significantly lower during noise than in silence. Correlations with age were noted for velocities in the right MCA during PASAT performance in silence and for PI on both sides during PASAT performed in noise conditions. Noise impairs the CBF during mental tasks. A comparison of changes in CBF parameters correlated with age suggests that the involvement of the nondominant hemisphere in managing with noise effects increases with age.

Оценка латерализации церебральной гемодинамики при выполнении вербальных мнестических заданий методом функциональной транскраниальной допплерографии

There are the preliminary results of the research of interhemispheric asymmetry of cerebral hemodynamics during the performance of auditory-verbal and visual memory tasks with the use of functional transcranial doppler ultrasound (fTCD). The fTCD is considered as a non-invasive and objective method for assessment the dominant hemisphere for verbal functions. The aim of two experiments was to analyze the effect of a) different types of verbal and nonverbal tasks and b) the conditions of the mnestic activity performance (memorize and recognize) on the changes of blood flow velocity in left and right hemispheres in 62 healthy subjects. There are preliminary results of possible application fTCD to identify the dominant hemisphere for speech functions with combination of concrete verbal cognitive tasks and condition of its presentation.

Cerebral language lateralisation attenuates in old age: evidence from functional transcranial Doppler methods

Cerebral language lateralisation attenuates in old age: evidence from functional transcranial Doppler methods

Perinatal testosterone exposure and cerebral lateralisation in adult males: Evidence for the callosal hypothesis

Two competing theories address the influence of foetal testosterone on cerebral laterality: one proposing exposure to high foetal testosterone concentrations is related to atypical lateralisation (Geschwind–Galaburda hypothesis), the other that high foetal testosterone concentrations exaggerate typical lateralisation (callosal hypothesis). The current study examined the relationship between cord testosterone concentrations and cerebral laterality for language and spatial memory in adulthood. Male participants with high (>0.15nmol) and low (<0.10nmol) cord testosterone levels were invited to take part in the study (n=18 in each group). Cerebral laterality was measured using functional Transcranial Doppler ultrasonography, while participants completed word generation and visual short-term memory tasks. Typical left lateralisation of language was more common in the high-testosterone group than in the low-testosterone group, χ2=4.50, df=1, p=034. Spatial memory laterality was unrelated to cord testosterone level. Our findings indicate that foetal testosterone exposure is related to language laterality in a direction that supports the callosal hypothesis.

No population bias to left-hemisphere language in 4-year-olds with language impairment.

Background. An apparent paradox in the field of neuropsychology is that people with atypical cerebral lateralization do not appear to suffer any cognitive disadvantage, yet atypical cerebral lateralization is more common in children and adults with developmental language disorders. This study was designed to explore possible reasons for this puzzling pattern of results.Methods. We used functional transcranial Doppler ultrasound (fTCD) to assess cerebral blood flow during language production in 57 four-year-olds, including 15 children who had been late-talkers when first seen at 20 months of age. We categorized cerebral lateralization as left, right or bilateral, and compared proportions with each type of laterality with those seen in a previously tested sample of children aged 6–16 years. We also compared language scores at 4 years for those with typical and atypical lateralization, and then looked at the association the opposite way: comparing those with typical or impaired language in terms of their cerebral lateralization.Results. The distribution of types of cerebral lateralization was similar for 4-year-olds to that seen in older children. Overall, cerebral lateralization was not predictive of language level. However, for children who had language difficulties at 20 months and/or 4 years (N = 21), there was no population bias to left-hemisphere language activation, whereas children without language problems at either age showed a pronounced bias to left-sided language lateralization. Nevertheless, many children with right hemisphere language had no indications of language difficulties, confirming that atypical cerebral asymmetry is not a direct cause of problems.Conclusions. We suggest that atypical lateralization at the individual level is not associated with language impairment. However, lack of lateralization at the population level is a marker of risk for language impairment, which could be due to genetic or non-genetic causes.

Inferring common cognitive mechanisms from brain blood-flow lateralization data: a new methodology for fTCD analysis.

Current neuroimaging techniques with high spatial resolution constrain participant motion so that many natural tasks cannot be carried out. The aim of this paper is to show how a time-locked correlation-analysis of cerebral blood flow velocity (CBFV) lateralization data, obtained with functional TransCranial Doppler (fTCD) ultrasound, can be used to infer cerebral activation patterns across tasks. In a first experiment we demonstrate that the proposed analysis method results in data that are comparable with the standard Lateralization Index (LI) for within-task comparisons of CBFV patterns, recorded during cued word generation (CWG) at two difficulty levels. In the main experiment we demonstrate that the proposed analysis method shows correlated blood-flow patterns for two different cognitive tasks that are known to draw on common brain areas, CWG, and Music Synthesis. We show that CBFV patterns for Music and CWG are correlated only for participants with prior musical training. CBFV patterns for tasks that draw on distinct brain areas, the Tower of London and CWG, are not correlated. The proposed methodology extends conventional fTCD analysis by including temporal information in the analysis of cerebral blood-flow patterns to provide a robust, non-invasive method to infer whether common brain areas are used in different cognitive tasks. It complements conventional high resolution imaging techniques.

Investigating language lateralization during phonological and semantic fluency tasks using functional transcranial Doppler sonography

Although there is consensus that the left hemisphere plays a critical role in language processing, some questions remain. Here we examine the influence of overt versus covert speech production on lateralization, the relationship between lateralization and behavioural measures of language performance and the strength of lateralization across the subcomponents of language. The present study used functional transcranial Doppler sonography (fTCD) to investigate lateralization of phonological and semantic fluency during both overt and covert word generation in right-handed adults. The laterality index (LI) was left lateralized in all conditions, and there was no difference in the strength of LI between overt and covert speech. This supports the validity of using overt speech in fTCD studies, another benefit of which is a reliable measure of speech production.

An analysis of cerebral blood flow from middle cerebral arteries during cognitive tasks via functional transcranial Doppler recordings

Functional transcranial Doppler (fTCD) is a useful medical imaging technique to monitor cerebral blood flow velocity (CBFV) in major cerebral arteries. In this paper, CBFV changes in the right and left middle cerebral arteries (MCA) caused by cognitive tasks, such as word generation tasks and mental rotation tasks, were examined using fTCD. CBFV recordings were collected from 20 healthy subjects (10 females, 10 males). We obtained both the raw CBFV signal and the envelope CBFV signal, which is the maximal velocity to gain more information about the changes and hemisphere lateralization in cognitive tasks compared to the resting state. Time, frequency, time–frequency, and information-theoretic features were calculated and compared. Sex effects were also taken into consideration. The results of our analysis demonstrated that the raw CBFV signal contained more descriptive information than the envelope signals. Furthermore, both types of cognitive tasks produced higher values in most signal features. Geometric tasks were more distinguished from the rest-state than verbal tasks and the lateralization was exhibited in right MCA during geometric tasks. Our results show that the raw CBFV signals provided valuable information when studying the effects of cognitive tasks and lateralization in the MCA.

Cerebral lateralization for language in deaf children with cochlear implantation

Functional Transcranial Doppler ultrasonography (fTCD) was used to investigate the effects of early acoustic deprivation and subsequent reafferentation on cerebral dominance for language in deaf children provided with Cochlear Implantation (CI). Twenty children with CI (13 in right ear and 7 in left ear) and 20 controls matched for age, sex and handedness were administered a fTCD animation description task. Left hemisphere dominance for language with comparable mean Laterality Indexes (LIs) was found in children with CI and controls; right-ear implanted subjects showed cerebral activation controlateral to implanted ear more frequently than left-ear implanted ones. Linguistic proficiency of CI recipients was below age expectation in comparison to controls; language scores did not significantly differ between children with left and right LI, whereas both age and side of implantation were significantly related to language outcome. Theoretical implication and potential clinical application of fTCD in CI management are discussed.

Effects of Action Observational Training on Cerebral Hemodynamic Changes of Stroke Survivors: A fTCD Study

[Purpose] The purpose of this study was to investigate the effect of Action Observational Training (AOT) on cerebral hemodynamic changes, including cerebral blood flow velocity (CBFV) and cerebral blood flow volume (CBFvol) in healthy subjects and stroke survivors. [Subjects] This study had a cross-sectional design. Seven healthy subjects and six patients with a first-time stroke participated in this study. [Methods] All subjects were educated about AOT, and we measured their systolic peak velocity (Vs), mean flow velocity (Vm), pulsatility index (PI), and resistance index (RI) in the middle cerebral artery (MCA), the anterior cerebral artery (ACA), and the posterior cerebral artery (PCA), before and after performance of AOT, using Functional Transcranial Doppler (fTCD) with a 2-MHz probe. [Results] Both healthy subjects and stroke survivors showed significant improvements of Vs and Vm in MCA, ACA and PCA after AOT. [Conclusion] Our findings indicate that AOT increases CBFV in healthy subjects and stroke survivors, because the brain requires more blood in order to meet the metabolic demand of the brain during AOT.

EPA-0705 – Correlates of behavior and cerebral hemodynamics during complex functioning in young adulthood

Background Functional transcranial Doppler sonography (fTCD) of basal cerebral arteries is a non-invasive technique that allows monitoring of cerebral hemodynamics during cognitive performance with a high temporal resolution. There is ample evidence that age impacts on performance and cerebral hemodynamics. This study investigated those associations between a sample of young adult healthy subjects performing the Trail Making Test (TMT), a means of selective attention and complex cognitive functioning. Methods We examined cerebral hemodynamic parameters in the middle cerebral arteries (MCA) using fTCD while healthy subjects (mean age 31.5 years) simultaneously performed the TMT. Results There was a significant slowing with older age (age 30 years or older) for both selective attention and complex cognitive functioning, and older age was associated with significantly lower mean cerebral blood flow velocity (MFV) in males during complex functioning. Young age (younger than 30 years) was associated with initially bilateral and then significantly left sided lateralization, and older age with a bilateral pattern. Conclusions These novel results suggest that, in a relatively young age continuum sample, older age results in slowing and decreased brain perfusion, though in a diverse manner. Younger age is associated with alternating pattern of lateralization implying a diverse cognitive style with age as covariate. It adds to the notion that fTCD is a substantial tool to significantly link age related modulation of performance with dedicated parameters of brain perfusion.

EPA-1297 - Lateralization of cerebral hemodynamics in schizophrenia during the trail making test: a functional transcranial doppler sonography study

Schizophrenia is a major mental disorder, with complex symptoms involving psychosis, apathy and cognitive impairment. The Trail Making Test (TMT) is a useful tool to assess cognitive functioning. Functional transcranial Doppler sonography (fTCD) of basal cerebral arteries is a noninvasive technique that allows monitoring of cerebral hemodynamics with a high temporal resolution during cognitive tasks. We assessed cerebral hemodynamics and lateralization in the middle cerebral arteries (MCA) using fTCD while patients with chronic schizophrenia and healthy subjects performed the TMT Part A and B, as well as a control task. fTCD was used to asses bilateral mean cerebral blood flow velocity (MFV) changes in the middle (MCA) and anterior (ACA) cerebral arteries. Fifteen patients with chronic Schizophrenia and 20 healthy control subjects with similar sociodemographic characteristics performed the TMT during fTCD measurements of the MCA and ACA. Schizophrenia patients demonstrated an overall poorer performance, with a significant different lateralization pattern for both forms of TMT than healthy subjects. There was a significant slowing both forms of TMT, schizophrenia was associated with initially left sided lateralization. Healthy subjects showed a bilateral pattern. These novel results show performance and brain perfusion abnormalities in schizophrenia, supporting the idea that cognitive performance has a pathological functional correlate predominantly in the lateral hemispheres of the brain. It adds to the notion that fTCD is a valuable tool to correlate psychological paradigms with brain perfusion.

Mental Workload Assessment: From the Perspective of Neuroergonomics

The assessment of mental workload is undergoing transition from traditional ergonomics to neuroergonomics. The neuroimaging techniques such as electroencephalography (EEG), event-related potentials (ERPs), functional magnetic resonance imaging (fMRI), functional Near-infrared spectroscopy (fNIRS) and transcranial doppler (TCD) provide the strong supports for this revolution. It is found that under single-task condition, with the increase of mental workload level, alpha-band power decreases, theta-band power increases. In addition, the cerebral blood flow in the regions of the prefrontal cortex (PFC), the average oxygenation changes in the regions of left inferior frontal gyrus (LIFG) and the cerebral blood flow velocity (CBFV) also increase. Under dual-task condition, with the increase of mental workload level, the amplitudes of several ERPs components elicited by the secondary task stimuli (e.g., N1, Novelty P3, P3b, etc) decrease. Based on these findings, researchers have achieved the real-time online evaluation of mental workload by pattern classification algorithms (e.g.,artificial neural network, support vector machine). But all of these techniques have their own advantages and disadvantages on several aspects (i.e., sensitivity, diagnosticity, primary task intrusion, implementation requirements, acceptability and reliability). In the future, researchers should promote the combination of these neuroimaging technologies, improve their acceptability and enhance their sensitivity and diagnosticity via pattern recognition algorithms.

Shared Brain Lateralization Patterns in Language and Acheulean Stone Tool Production: A Functional Transcranial Doppler Ultrasound Study

BackgroundThe popular theory that complex tool-making and language co-evolved in the human lineage rests on the hypothesis that both skills share underlying brain processes and systems. However, language and stone tool-making have so far only been studied separately using a range of neuroimaging techniques and diverse paradigms.Methodology/Principal FindingsWe present the first-ever study of brain activation that directly compares active Acheulean tool-making and language. Using functional transcranial Doppler ultrasonography (fTCD), we measured brain blood flow lateralization patterns (hemodynamics) in subjects who performed two tasks designed to isolate the planning component of Acheulean stone tool-making and cued word generation as a language task. We show highly correlated hemodynamics in the initial 10 seconds of task execution.Conclusions/SignificanceStone tool-making and cued word generation cause common cerebral blood flow lateralization signatures in our participants. This is consistent with a shared neural substrate for prehistoric stone tool-making and language, and is compatible with language evolution theories that posit a co-evolution of language and manual praxis. In turn, our results support the hypothesis that aspects of language might have emerged as early as 1.75 million years ago, with the start of Acheulean technology.

Multimodal Assessment of Optokinetic Visual Stimulation Response in Migraine With Aura

This study aimed to assess activation patterns and the hemodynamic response to optokinetic stimulation in migraine with aura patients compared with controls. It has been proposed that altered visual motion processing in striate and extrastriate visual areas is present in migraine patients and might play a role in the pathophysiology of the disease. Besides activating a large visual network, optokinetic stimulation in particular has been shown to provoke symptoms associated with migraine. In this study, we examined the response to visual stimulation in 18 migraine with aura patients compared with 18 healthy controls by using functional magnetic resonance imaging and functional transcranial Doppler, thereby assessing the activation pattern of the visual areas (V1-V5) as well as the vasomotor reactivity of the posterior cerebral artery. For stimulation, we used a vertically rotating optokinetic drum with complex colored figures. Group analysis of migraineurs with aura vs controls revealed different activation patterns in functional magnetic resonance imaging: attenuation of the physiological right lateralization with a significantly increased activation in the left V5 complex, the left area V3, and the right V5 complex. Analysis of the visually evoked flow response of the cerebral blood flow velocity in the posterior cerebral artery showed a larger side-difference of the offset latency (P < .05) and a reduced steepness of the decreasing slope on the left side (P < .05). Combining examinations with a good structural (functional magnetic resonance imaging) and temporal (functional transcranial Doppler) resolution is a novel approach to migraine pathophysiology. Our findings of an altered pattern of activation by optokinetic visual stimulation with hyperresponsiveness in visual areas activated by motion perception (V5 and V3) further strengthen the concept of an interictal motion-processing deficit in migraine. This is complemented by the slower restitution of the visually evoked flow response after stimulus offset in migraine with aura patients.