‘Brain works overtime’ to help out after a stroke

When one part of the brain is damaged, surrounding parts work harder to compensate and keep us functioning as normal, researchers have found. The discovery comes as part of a project exploring the impact of a stroke on the brain.

As part of the research carried out at the Functional Imaging Laboratory at UCL (University College London) scientists, funded by the Wellcome Trust, have been investigating the effects of a stroke using a non-invasive procedure called Transcranial Magnetic Stimulation (TMS).TMS sends electrical pulses into the brain creating a controlled, short-term reduction in responsiveness – similar to those experienced after a stroke. During this procedure volunteers performed a series of basic tasks such as tapping out a rhythm with their fingers while their brain activity was monitored with a PET scan. The scans show an increase in activity in the areas surrounding the impaired part of the brain – again, similar to those experienced by stroke patients.

Lead researcher Dr Lucy Lee explained:

“That the brain responds to these manufactured impairments in the same way as it does to the damage caused by a stroke suggests that the additional activity seen after a stroke is part of a normal brain response. In effect, healthy parts of the brain seem to be working overtime to try and make up for the impaired tissue and enable the person to function normally.

“It appears that when the brain detects that something isn’t right it maps a different route to continue performing tasks as normal.

“The similarity between the results of this experiment and the brain activity in stroke patients sets us the challenge of developing this into a robust model of a stroke. If we can do this, it could dramatically improve our understanding of what’s happening to the brain and, of course, ultimately to develop the most effective treatments.”

It is long known that after a stroke the parts of the brain surrounding the damaged area behave differently. This new study has encouraged researchers as it suggests rather than this being a sign of damage from the stroke, it may be the healthy parts of the brain trying to overcome the damage. The brain seems to be adapting to ensure that physical abilities and actions continue as normal.

The TMS procedure works by creating a magnetic field which generates a mild electrical current at a precise location in the primary motor cortex – the part of the brain which controls voluntary muscle activity throughout the body. This current interferes with the normal mechanisms the brain uses to send messages to trigger physical action, even those needed for the most basic tasks.

The procedure takes about one hour to complete and doesn’t cause any harm or side effects to the volunteers - most don’t even notice any difference in their performance of physical tasks, such as finger tapping or handwriting.

This technique gives rise to the possibility of healthy volunteers being able to assist the in understanding of the brain’s reaction to a stroke and how to most effectively treat it. Potentially, it could help overcome some of the difficulties experienced in trying to research strokes, including finding suitable volunteers.

Each year over 130,000 people in England and Wales have a stroke and about 60,000 people die as a result.Stroke is also the largest single cause of severe disability in England and Wales with over 250,000 people being affected at any one time.

ENDS

Media contact:

Mark Anderson – 020 7611 8612

Notes to editor:

1.The Wellcome Trust is an independent research funding charity established in 1936 under the will of the tropical medicine pioneer Sir Henry Wellcome. The Trust’s mission is to foster and promote research with the aim of improving human and animal health and it currently spends over £400 million per annum.