Unlike the adult human brain, the neonatal brain may respond to external stimulus with an increase in deoxyhemoglobin, corresponding to a negative blood oxygen level-dependent (BOLD) signal on functional MRI, according to research published February 20 online ahead of print in the Proceedings of the National Academy of Sciences. Researchers studied the evolution of the cortical blood flow response in neonatal rats during postnatal development using exposed-cortex multispectral optical imaging. Day-12–13 rats, which are equivalent to human newborns, exhibited an inverted hemodynamic response with early signs of oxygen consumption, followed by delayed, active constriction of pial arteries. The hemodynamic response matured through the development of an initial hyperemic (ie, positive BOLD) phase that eventually masked oxygen consumption and balanced vasoconstriction toward adulthood.
Neurologists may have an approximately 15-year interval during which to treat patients with amyloid buildup in an attempt to prevent Alzheimer’s disease, according to research published February 27 online ahead of print in Neurology. Investigators studied 260 participants ages 70 to 92, all of whom underwent two or more serial amyloid PET examinations. A total of 205 participants were cognitively normal, 47 had mild cognitive impairment, and eight had Alzheimer dementia. Rates of amyloid accumulation were low among patients who had low or high amyloid levels at baseline, and high among patients with moderate levels of amyloid at baseline. The researchers estimated that the average time required to travel from a low rate of accumulation to a high rate of accumulation is approximately 15 years.
Overexpression of α-synuclein may be associated with hypertrophy of membrane systems of the presynaptic terminal and the disruption of vesicle recycling, according to a study published in the February 6 issue of the Journal of Neuroscience. Progressive degeneration and cell death are the potential consequences of this disruption. Overexpressed α-synuclein was associated with a large and poorly characterized membranous organelle system of the presynaptic terminal, as well as with smaller vesicular structures within these boutons. The α-synuclein was found in several parts of the protein degradation pathway, including multivesicular bodies in the axons and lysosomes within neuronal cell bodies. The data support the conclusion that α-synuclein is involved in processes associated with the sorting, channeling, packaging, and transport of synaptic material destined for degradation, said the investigators.
Patients with multiple sclerosis (MS) and problems with cognition, memory, attention, or concentration have more damage to areas in the brain responsible for cognitive processes than patients with MS who do not have cognitive problems, according to research published in the March 6 Neurology. Investigators used MRI and diffusion tensor imaging to compare brain measurements in 20 patients with MS who had related cognitive problems, 35 patients with MS who did not have cognitive problems, and 30 healthy controls. About 49% of brain white matter examined had impaired integrity in individuals with MS and no cognitive problems, compared with 76% in patients with MS and cognitive problems. White matter dysfunction was particularly evident in the thalamus in individuals with MS-related cognitive problems.
Epidural steroid injections (ESIs) may be associated with significantly less improvement among patients with spinal stenosis, according to a study published in the February 15 Spine. Researchers performed a subgroup analysis of a prospective, randomized database from the Spine Patient Outcomes Research Trial. ESI patients who ultimately underwent surgery had an average 26-minute increase in operative time and an increased length of stay by 0.9 days. Over four years, surgically treated ESI patients had significantly less improvement in 36-Item Short Form Health Survey (SF-36) Physical Function, compared with patients who had not received ESI. Nonsurgically treated patients who received ESI also had significantly less improvement in SF-36 Body Pain and SF-36 Physical Function than patients who did not receive ESI.
C9RANT, an abnormal protein that forms as a result of genetic abnormalities, may play a role in the development of amyotrophic lateral sclerosis (ALS) or frontotemporal dementia (FTD), researchers reported in the February 20 issue of Neuron. Investigators found insoluble accumulations of C9RANT in the brain tissue of patients with ALS or FTD, but not in patients with other neurodegenerative diseases. Repeat expansions in a noncoding region of the C9ORF72 gene are the major cause of C9RANT, and these expansions are the most common cause of ALS and FTD. The investigators found C9RANT in brain tissue after creating a novel antibody to detect it. C9RANT is a potential biomarker for FTD and ALS and a potential target to prevent neuronal loss, according to the researchers.
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