Objectives: The magnitude of the blood oxygen dependent level (BOLD) functional MRI (fMRI) response to visual stimulation is reduced in the small vessel disease cerebral amyloid angiopathy (CAA), reflecting impaired vascular reactivity. We determined whether BOLD responses were reduced in another small vessel disease, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).
Methods: BOLD fMRI data were collected using a visual stimulus (contrast-reversing checkerboard) and motor task (finger-tapping). The amplitude of BOLD responses in the visual cortex (visual stimulus) and motor cortex (motor task) were compared between 5 CADASIL, 18 CAA and 18 control subjects, controlling for age and hypertension.
Results: BOLD response varied by group for the visual stimulus (p<0.001) but not the motor task (p=0.47). After adjusting for age and hypertension, the estimated mean visual cortex BOLD amplitude response was 3.95% in CADASIL (95% confidence interval, CI 3.15-4.75%), 1.73% in CAA (95% CI 1.19-2.27%), and 2.88% (95% CI 2.39-3.37%) in controls. In CADASIL, the visual BOLD response was greater than in CAA (p<0.001) and controls (p=0.04).
Conclusions: We observed increased and unchanged BOLD amplitude responses in the visual and motor cortices of CADASIL patients, respectively. This suggests that cortical blood flow regulation by neuronal activity may be relatively preserved in CADASIL, in contrast to CAA where occipital vascular reactivity is impaired. Cortical vascular reactivity in CADASIL may be preserved because the disease-related injury is primarily subcortical, whereas increased activation may reflect compensatory mechanisms for subcortical injury.
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http://dx.doi.org/10.1016/j.jns.2017.02.004 | DOI Listing |
Osteoarthritis, a major global cause of pain and disability, is driven by the irreversible degradation of hyaline cartilage in joints. Cartilage tissue engineering presents a promising therapeutic avenue, but success hinges on replicating the native physiological environment to guide cellular behavior and generate tissue constructs that mimic natural cartilage. Although electrical stimulation has been shown to enhance chondrogenesis and extracellular matrix production in 2D cultures, the mechanisms underlying these effects remain poorly understood, particularly in 3D models.
View Article and Find Full Text PDFFront Psychol
December 2024
Graduate School of Humanities and Social Sciences, Hiroshima University, Higashihiroshima, Hiroshima, Japan.
Sense of body ownership has been studied using rubber hand illusion (RHI) and full-body illusion (FBI). It has recently become clear that consciously interpreting a fake body as one's own in a top-down manner influences these body illusions. Furthermore, a study interestingly found that the influence of top-down interpretation was moderated by the degree of depersonalization, which was a symptom of a lack of sense of body ownership.
View Article and Find Full Text PDFAdaptive optics scanning light ophthalmoscopy (AOSLO) enables high-resolution retinal imaging, eye tracking, and stimulus delivery in the living eye. AOSLO-mediated visual stimuli are created by temporally modulating the excitation light as it scans across the retina. As a result, each location within the field of view receives a brief flash of light during each scanner cycle (every 33-40 ms).
View Article and Find Full Text PDFRecent work has claimed that most apparently cross-modal responses in sensory cortex are instead caused by the face movements evoked by stimuli of the non-dominant modality. We show that visual stimuli rarely trigger face movements in awake mice; when they occur, such movements do not explain visual responses in auditory cortex; and in simultaneous recordings, face movements drove artifactual cross-modal responses in visual but not auditory cortex. Thus face movements do not broadly explain cross-modal activity across all stimulus modalities.
View Article and Find Full Text PDFSparse coding enables cortical populations to represent sensory inputs efficiently, yet its temporal dynamics remain poorly understood. Consistent with theoretical predictions, we show that stimulus onset triggers broad cortical activation, initially reducing sparseness and increasing mutual information. Subsequently, competitive interactions sustain mutual information as activity declines and sparseness increases.
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