New evidence swells brain morphometry understanding

Impressive international data from MRI assessment of subcortical brain structures across the lifespan confirms mostly age-related decreases in volume from peaks typically early in life.

The study of more than 18,000 healthy individuals 3-90 years of age found the volume of the caudate, putamen, globus pallidus and nucleus accumbens peaked early during the first decade of life and declined immediately after.

Thalamus, hippocampus and amygdala volumes peaked during the first 2–3 decades of life, remained largely stable until the sixth decade and then declined gradually.

However the volume of the lateral ventricles increased steadily with age.

The data may be used to develop normative reference values for neuroimaging phenotypes and assist in better understanding developmental and ageing changes in the brain.

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Researchers discover small window of opportunity for best recovery after stroke

An international study has shown, for the first time, that the capacity for the human brain to reorganise synaptic connections and recover itself after stroke peaks around two weeks post stroke and diminishes over time.

The finding, published in Neurorehabilitation and Neural Repair, is the first neurophysical evidence supporting the idea that until now has only been documented in animal studies.

Investigators in Adelaide and the UK followed the recovery of 60 ischaemic stroke patients up to one year post stroke and used continuous transcranial magnetic stimulation (cTBS) to repetitively activate different hemispheres of the motor cortex to measure brain plasticity.

The Adelaide laboratory tested the stroke damaged motor cortex while the London laboratory tested the non-stroke damaged hemisphere.

According to investigators, led by Dr Brenton Hordacre from the University of South Australia’s Body in Mind research group, plasticity was strongest in the two weeks immediately after stroke in the non-damaged motor cortex but there was no change in the damaged hemisphere in response to cTBS.

Investigators say behavioural training given during this brief period may be especially effective in supporting post stroke recovery.

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White matter changes a feature of frontotemporal dementia

New research suggests that white matter changes, called hyper intensities and commonly linked to vascular health problems and Alzheimer’s disease, may also be a core feature of frontotemporal dementia.

The finding is based on a study involving 64 people with frontotemporal dementia, 65 people with Alzheimer’s disease and 66 people without dementia who had brain scans and other tests.

Participants were followed for an average of two years. Autopsy information was available for 13 of the people with frontotemporal dementia and five of the people with Alzheimer’s disease.

Researchers from the University of Sydney found that the total volume of white matter hyperintensities in the brain was larger in people with frontotemporal dementia than in the people with Alzheimer’s disease or the healthy control group.

The average volume of white matter hyperintensities in people with frontotemporal dementia was 0.76 mL compared to 0.40 mL in people with Alzheimer’s disease and 0.12 mL in people without dementia.

What’s more, the amount of white matter hyperintensities was associated with the severity of a person’s frontotemporal dementia, including the severity of their symptoms and everyday difficulties, but it was not associated with having vascular risk factors such as high blood pressure and high cholesterol as was expected.

The Neurology study also reveals  certain areas of the brain where higher amounts of white matter hyperintensities develop are associated with worse cognitive performance. For example, in both frontotemporal dementia and Alzheimer’s disease, increased white matter hyperintensities in the corpus callosum was associated with attention problems.

“White matter hyperintensities should be viewed as a core feature of frontotemporal dementia and Alzheimer’s disease that can contribute to cognitive problems, not simply a marker of vascular disease,” investigators said

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