Changes in cerebral blood flow (CBF) and metabolism are now widely used to map and quantify neural activity, although the underlying mechanism for these changes is still incompletely understood. Magnetic resonance spectroscopy (MRS) at 3T, synchronized with a 32-s block design visual stimulation paradigm, was employed to investigate activation-induced changes in temperature and metabolism in the human primary visual cortex. A marginally significant increase in the local temperature of the visual cortex was found (0.1 degrees C, P = 0.09), excluding the possibility of a temperature decrease (95% confidence interval (CI) = 0.0-0.2 degrees C), which was previously suggested. A comparison with models of thermal equilibrium in the presence of blood flow suggests that an increase in heat production during activation, greater than or at least equal to that produced by the complete oxidative metabolism of the elevated glucose (Glc) utilization accompanying activation, would be required to offset the cooling effects of the increased blood flow. The total pools of glutamate (Glu), glutamine (Gln), myo-Inositol (mI), N-acetylaspartate (NAA), choline (Cho), and lactate (Lac) were not significantly affected by activation. Limits on Lac concentration changes were too weak to constrain theories of the metabolic use of elevated Glc consumption during stimulation, and emphasize the challenges of measuring even large Lac changes accompanying stimulation.
Aims: The aim of this study was to investigate the whole-brain asymmetry changes in spinocerebellar ataxia type 3 (SCA3) and their association with movement disorders.
Methods: Voxel-based morphometry (VBM) was used to assess asymmetry in gray matter (GM) volume in 83 genetically confirmed SCA3 patients and 83 sex- and age-matched healthy controls (HCs). The asymmetry index (AI) was analyzed for partial correlation with disease severity, as measured by the Scale for Assessment and Rating of Ataxia (SARA) and International Cooperative Ataxia Rating Scale (ICARS).
For most of my career, I focused on understanding how and where spatial context, the place where things happen, is represented in the brain. My interest in this began in the early 1990's, during my postdoctoral training with David Amaral, when we defined the rodent homolog of the primate parahippocampal cortex, a region implicated in processing spatial and contextual information. We parceled out the caudal portion of the rat perirhinal cortex (PER) and called it the postrhinal cortex (POR).
Learning new categories is fundamental to cognition, occurring in daily life through various sensory modalities. However, it is not well known how acquiring new categories can modulate the brain networks. Resting-state functional connectivity is an effective method for detecting short-term brain alterations induced by various modality-based learning experiences.
The neural representations for compositional processing have so far been mostly studied during sentence comprehension. In an fMRI study of sentence production, we investigated the brain representations for compositional processing during speaking. We used a rapid serial visual presentation sentence recall paradigm to elicit sentence production from the conceptual memory of an event.
Background: Postoperative subdural hematoma (SDH) typically presents with headache, impaired consciousness, hemiplegia, gait disturbance, and aphasia but can also present with visual impairment.
Observations: A 52-year-old woman diagnosed with Chiari malformation type I and syringomyelia underwent foramen magnum decompression. Cerebrospinal fluid was lost due to arachnoid injury during the procedure.
