The dorsal visual stream, often referred to as the 'where' stream, represents the pathway taken by visual information from the primary visual cortex to the posterior parietal lobe and onwards. It partners the ventral or 'what' stream, the subject of a previous review and largely a temporal-based system. Here, we consider the dorsal stream disorders of perception (simultanagnosia, akinetopsia) along with their consequences on action (eg, optic ataxia and oculomotor apraxia, along with Balint's syndrome). The role of the dorsal stream in blindsight and hemispatial neglect is also considered.
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http://dx.doi.org/10.1136/practneurol-2015-001168 | DOI Listing |
Quant Imaging Med Surg
January 2025
Department of Radiology, Beijing Youan Hospital, Capital Medical University, Beijing, China.
Background: Approximately half of human immunodeficiency virus (HIV) patients experience HIV-associated neurocognitive disorders (HAND); however, the neurophysiological mechanisms underlying HAND remain unclear. This study aimed to evaluate changes in functional brain activity patterns during the early stages of HIV infection by comparing local and global indicators using resting-state functional magnetic resonance imaging (rs-fMRI).
Methods: A total of 165 people living with HIV (PLWH) but without neurocognitive disorders (PWND), 173 patients with asymptomatic neurocognitive impairment (ANI), and 100 matched healthy controls (HCs) were included in the study.
Microvasc Res
January 2025
Primary Health Care Center, Department of Health, Medicine and Caring Sciences, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden; Wallenberg Centre for Molecular Medicine, Linköping University, Linköping, Sweden. Electronic address:
Introduction: Little is known about the day-to-day variability of different skin microcirculation parameters, and how this variability is influenced by age and sex. The aim was to examine the day-to-day variability of microcirculatory parameters in relation to age and sex.
Methods: The cutaneous microcirculation was measured using a fiber optic probe integrating laser Doppler flowmetry (LDF) and diffuse reflectance spectroscopy (DRS) to measure oxygen saturation, red blood cell (RBC) tissue fraction, speed-resolved and conventional perfusion.
Agri
January 2025
Department of Physical Medicine and Rehabilitation, Bilkent City Hospital, Ankara, Türkiye.
Objectives: The present study aimed to compare the pressure-pain threshold (PPT) values in patients with rheumatoid arthritis (RA) and age-gender matched controls with chronic nonspecific low back pain and to determine whether PPT values could be beneficial as a disease activity predictor after secondary fibromyalgia had been ruled out.
Methods: This study contained a cross-sectional observational study of participants with RA and chronic nonspecific low back pain controls without fibromyalgia. Visual analog scale (VAS), fatigue severity scale (FSS), pain catastrophizing scale (PCS), health assessment questionnaire (HAQ), hospital anxiety and depression scale (HADS), and disease activity score (DAS28) were administered.
Hum Brain Mapp
February 2025
Department of Radiology, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland.
In contrast to blood-oxygenation level-dependent (BOLD) functional MRI (fMRI), which relies on changes in blood flow and oxygenation levels to infer brain activity, diffusion fMRI (DfMRI) investigates brain dynamics by monitoring alterations in the apparent diffusion coefficient (ADC) of water. These ADC changes may arise from fluctuations in neuronal morphology, providing a distinctive perspective on neural activity. The potential of ADC as an fMRI contrast (ADC-fMRI) lies in its capacity to reveal neural activity independently of neurovascular coupling, thus yielding complementary insights into brain function.
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January 2025
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
MT+ is pivotal in the dorsal visual stream, encoding tool-use characteristics such as motion speed and direction. Despite its conservation between humans and monkeys, differences in MT+ spatial location and organization may lead to divergent, yet unexplored, connectivity patterns and functional characteristics. Using diffusion tensor imaging, we examined the structural connectivity of MT+ subregions in macaques and humans.
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