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Dysfunction of the visual cortex is implicated in psychosis and recently, the extrastriate visual cortex (V5/MT) has been causally linked to visual hallucinations through lesion network mapping. Transcranial electric stimulation (tES) has been shown to improve psychotic symptoms and cognition in psychosis spectrum disorders. However, few investigations have used novel approaches, such as high definition tES (HD-tES) to target specific brain circuits. Previously, we showed that stimulation delivered to V5/MT using HD-tDCS (direct current) reduced Positive and Negative Syndrome Scale (PANSS) general symptoms in the short-term (5 days), while HD-tACS (alternating current) improved general symptoms and functioning in the long-term (30 days). Here, we aim to determine if HD-tES to V5/MT has altering effects on cognition and self-reported symptoms of psychosis, and to investigate the differences between self-reported and clinician-reported symptoms. A pilot open label study with a within-subjects, single blind, crossover design was conducted in order to characterize the efficacy of cathodal HD-tDCS and 2Hz delta HD-tACS for psychosis treatment. Enrolled patients received 20 mins of HD-tES twice daily for 5 consecutive days applied bilaterally to V5/MT with a washout between conditions. Assessments were performed at baseline, day 5, and day 30. HD-tACS treatment was found to improve cognition on Digit Sequencing, Tower of London, Semantic Fluency, and “S” Letter Fluency tasks as measured by brief assessment of cognition in schizophrenia (BACS) as well as symptoms of paranoid ideation and anger/hostility as measured by the symptom checklist 90 (SC-90) 1 month after treatment. HD-tDCS treatment yielded significant improvement on “F” Letter Fluency as measured by BACS and did not yield any significant improvement on SC-90 symptoms. Lastly, correlations between SC-90 and PANSS described a distinct relationship between the two scales and their measures of psychiatric morbidity. Ultimately, delta wave tACS may be able to improve cognition and certain symptoms of psychosis by altering cortico-cortico communication between relevant brain structures. Future large-scale investigations are needed to further solidify these results. / 2026-03-04T00:00:00Z

No / Until recently, it was widely believed that object position and object motion were represented independently in the visual cortex. However, several studies have shown that adaptation to motion produces substantial shifts in the perceived position of subsequently viewed stationary objects [[13]]. Two stages of motion adaptation have been proposed: an initial stage at the level of V1 and a secondary stage thought to be located in V5/MT [[4]]. Indeed, selective adaptation can be demonstrated at each of these levels of motion analysis [[5, 6]]. What remains unknown is which of these cortical sites are involved in modulating the positional representation of subsequently viewed objects. To answer this question directly, we disrupted cortical activity by using transcranial magnetic stimulation (TMS) immediately after motion adaptation. When TMS was delivered to V5/MT after motion adaptation, the perceived offset of the test stimulus was greatly reduced. In marked contrast, TMS of V1 had no effect on the changes that normally occur in perceived position after motion adaptation. This result demonstrates that the anatomical locus at which motion and positional information interact is area V5/MT rather than V1/V2.

Yes / Human neuropsychological and neuroimaging studies have raised the possibility that different attributes of optic flow stimuli, namely radial direction and the position of the focus of expansion (FOE), are processed within separate cortical areas. In the human brain, visual areas V5/MT+ and V3A have been proposed as integral to the analysis of these different attributes of optic flow stimuli. In order to establish direct causal relationships between neural activity in V5/MT+ and V3A and the perception of radial motion direction and FOE position, we used Transcranial Magnetic Stimulation (TMS) to disrupt cortical activity in these areas whilst participants performed behavioural tasks dependent on these different aspects of optic flow stimuli. The cortical regions of interest were identified in seven human participants using standard fMRI retinotopic mapping techniques and functional localisers. TMS to area V3A was found to disrupt FOE positional judgements, but not radial direction discrimination, whilst the application of TMS to an anterior sub-division of hV5/MT+, MST/TO-2, produced the reverse effects, disrupting radial direction discrimination but eliciting no effect on the FOE positional judgement task. This double dissociation demonstrates that FOE position and radial direction of optic flow stimuli are signalled independently by neural activity in areas hV5/MT+ and V3A. / This work was funded by the BBSRC (grant B/N003012/1).

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INTRODUÇÃO: O ultrassom transcraniano colorido (UTC) é um eficiente método para avaliação da circulação intracraniana e do fluxo sanguíneo cerebral em diversas condições clínicas incluindo o acidente vascular isquêmico agudo. Uma das principais limitação deste método reside na incapacidade de insonação intracraniana adequada através da janela transtemporal em até 20% dos pacientes. Neste contexto, surge a necessidade do desenvolvimento de uma metodologia estruturada que permitisse caracterizar a qualidade da janela transtemporal de forma mais detalhada e objetiva. No presente estudo, objetivamos: determinar a frequência de visualização dos principais marcos anatômicos pela insonação com UCT utilizando-se a janela transtemporal em pacientes com AVCI agudo; classificar o grau de dificuldade na visualização da primeira porção da artéria cerebral média (ACM) ipsilateral ao lado insonado; determinar a influência da idade, sexo, etnia no na qualidade da janela transtemporal pelo UTC. METODOLOGIA: Avaliamos prospectivamente todos os pacientes adultos, consecutivos, com o primeiro e único episódio de acidente vascular isquêmico no período de julho de 2014 a janeiro de 2015 com um exame de UTC (modo B e Doppler colorido). Dois examinadores classificaram a qualidade da janela transtemporal pelo modo B utilizando uma escore baseado na qualidade da visualização de referencias anatômicas (osso temporal contralateral, asa menor do esfenoide ipsilateral e mesencéfalo) variando de 0 (janela ausente) a 9 (excelente janela). Os preditores independentes de uma boa visualização do sinal da ACM ao UTC foram identificados através de um modelo de regressão logística multivariada selecionado pelo método backward. A acurácia do escore do modo B foi avaliada através dos parâmetro de sensibilidade, especificidade e estatística C (curva ROC). RESULTADOS: entre os 200 paciente incluídos no estudo (55% do sexo masculino e com idade média de 61,17 ± 15,22 anos) o osso temporal contralateral não foi visualizado em 48,5% dos casos, o mesencéfalo foi visualizado em 65% e a asa menor do esfenoide foi visualizada em 66%. A porção proximal da artéria cerebral media (M1) foi visualizada em 62% dos casos. Na análise multivariada, a idade (OR: 0,95; IC95%:0,92 - 0,99; p=0,011) e a pontuação no escore do modo B (OR: 2,97; IC95%:1,93- 4,55; p<0,001) foram preditores independentes de visualização do sinal da ACM ao UTC. A pontuação no escore do modo B mostrou um preditor acudado para subsequente visualização da artéria cerebral médica pelo Doppler colorido com uma área sob a curva ROC de 0,896 (p<0,001). O escore de 2 apresentou uma sensibilidade e especificidade de 80 e 87% para este fim, respectivamente. CONCLUSÃO: O escore do modo B baseado na visualização de referência anatômicas intracranianas pelo modo B do UTC é uma ferramenta útil com boa acurácia para capacidade de visualização do fluxo da artéria cerebral media ipsilateral ao UTC. Este escore permite descrever de forma mais detalhada a qualidade de janela transtemporal ao UTC, em suas diferentes aplicações. / INTRODUCTION: Transcranial Color-Coded Sonography (TCCS) is an widely-used method to assess the intracranial circulation and cerebral blood flow in several clinical conditions including acute ischemic stroke. One of the main limitations of this technic is related to the quality of the transtemporal window, which is poor in about 20% of cases. In this context, it is important to develop an structured approach to better define the quality of the transtemporal window. In this study we aimed to evaluate how frequently the main anatomic landmarks can be adequately visualized by TCCS in acute stroke patients using the transtemporal window; to assess the proportion of patients in which the ipsilateral middle cerebral artery of visualized by TCCS; and to identify the main predictors of a poor transtemporal window on TCCS. METHODS: We examined 200 consecutive acute ischemic stroke (AIS) patients, from July 2014 to January 2015. All patients underwent prospective TCCS evaluation. Visualization of the contralateral temporal bone (CTB), midbrain (MB) and lesser sphenoid wing (LSW) was scored on B-mode images. The resulting B-Mode Score varied from 0 (poor visualization) to 9 (perfect window). A multivariate logistic regression model (backward selection) was used to identify the independent predictors of visualization of the MCA signal by TCCS. The relationship between these B-Mode Score and visualization of the proximal portion of the ipsilateral MCA was assessed in terms of sensitivity, specificity, ROC curve and C statistics. RESULTS: Among 200 AIS patients (male 55%; mean age, 61.17 ± 15,22 years), CTB was invisible\' in 48,5%, the MB was visualized in 65%; and the LSW was seen in 66%. The M1 segment of the MCA was detected in 62% of cases. After multivariate analysis, age (OR: 0.95; 95CI%:0.92-0.99; p=0.011) and B-Mode score (OR: 2.97;95CI%:1.93-4.55; p<0.001) were independente predictors of visualization of MCA signal by TCCS. The BMode Score show good accuracy for the prediction of MCA visualization with an AUC of 0,896. (p<0,001) on the respective ROC curve. A cut-off of 2 on the B-mode score showed a sensitivity of 80% and a specificity of 87% for adequate MCA visualization by TCCS. CONCLUSION: The B-mode Score, which is based on the visualization of intracranial anatomical landmarks on B-Mode, appears to be a reliable way to characterize the quality of the transtemporal window, with a good accuracy as predictor for visualization of the ipsilateral MCA on TCCS. This score may allow more detailed characterization of the transtemporal window for different clinical applications of TCCS.

Early deterioration and long-term recurrence were common after stroke or transient ischemic attach (TIA), however, it is unclear whether they were correlated with active embolization and the consequent new cerebral infarct in acute phase. By employing TCD and diffusion weighted imaging (DWI), we studied the significance of the progression of MES and infarcts during acute phase on the clinical outcomes. We found that the disappearance of MES was correlated with better improvement on day 7 of recruitment; for the long-term outcome, occurrence of exacerbating infarct tended to predict recurrent stroke. Treatment aiming to reduce MES and prevent infarct exacerbation in acute phase may improve the prognosis after stroke. / Finally, one study was performed to assess the changes of hemodynamic parameters after stenting of severe stenosis in the MCA. We aimed to investigate whether TCD can reflect the lumen changes after revascularization and detect hyperperfusion. The findings showed that the velocity of stented MCA in most patients normalized within 24 hours after procedure, but the role of TCD in detecting restenosis in long run needed to be verified; no one suffered from hyperperfusion during the period of our study. The long-term outcomes of patients with normalized velocity versus those with persistently high velocity needed to be further studied. Apart from the velocity changes, changes of the collateral flow after intervention may also be an important part of hemodynamic changes. (Abstract shortened by UMI.) / It was suggested that anti-platelet therapy can reduce the MES, but little was known about the efficacy of low molecular weight heparin (LMWH) although in theory LMWH can reduce the red fibrin-dependent thromboemboli. As a sub-analysis of Fraxiparine in Ischemic Stroke (FISS)-tris study, our study did not show advantages of LMWH in eliminating MES compared with aspirin. / Previous studies showed the accuracy of TCD in diagnosis of middle cerebral artery (MCA) stenosis was variable and the positive predictive value (PPV) was less than 50% in a recent report. One of the important reasons was that most criteria were based on the velocity-only method, ignoring other non-velocity information. Thus, we tried to establish new diagnostic criteria by means of designing an assessment form which integrated more characteristics apart from the velocity acceleration. A composite score for each MCA was calculated according to following parameters in the form: Velocity Scale (score 0-6 for peak systolic velocities&lt;140 to &ge;300cm/s), Hemodynamic Scale (score 0-5 for focal or diffuse velocity increase; score 0-6 for differences between bilateral MCA; score 17 for damping velocity), Spectrum Scale (score 0-2 for normal spectrum, turbulence and musical murmurs). Our results showed that compared with the previously reported criteria, the score calculated from the assessment form yielded much more balanced accuracy against magnetic resonance angiography (MRA) and digital subtraction angiography (DSA). However, the composition of the assessment form was only based on personal experience and need to be further modified. Multicenter studies with large sample size are also needed to confirm the advantages of this new method. / Second, we performed three studies to investigate the relationship between the progression of MES and the short or long-term outcome and the relationship between MES and different treatments. / Hao, Qing. / Adviser: Ka Sing Wong. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3419. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 155-181). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

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