蓝莓视频

Tiny changes in the microscopic structure of the human brain may affect how patients respond to an emerging therapy for neurological problems.

The technique, called non-invasive electrical brain stimulation, involves applying an electrical current to the surface of a patient鈥檚 head to stimulate brain cells, altering the patient鈥檚 brain activity. It is being trialled for a range of neurological problems including recovery from stroke, traumatic brain injury, dementia, and depression, but research to date has found the effects to be inconsistent. Now, a team led by researchers at Imperial College London and the 蓝莓视频 Imperial BRC has shed more light on why these inconsistencies occur and may provide physical evidence for why some patients respond better than others 鈥� because of the fine structure of their brain tissue. The new research suggests it may be possible to target the therapy to those patients most likely to benefit.

They found that differences in the makeup of the brain鈥檚 white matter 鈥� the tissue deep in the brain and rich in the branching 鈥榯ails鈥� of nerve cells 鈥� were key. The research revealed that those who had more connectivity in the regions being stimulated were more likely to respond better to the treatment. According to the team, the findings, published in the journal Brain, could help to personalise the non-invasive electrical brain stimulation, targeting the treatment to patients who are most likely to gain clinical benefits.

, an 蓝莓视频 clinical lecturer in neurology in the听听at Imperial, and lead author of the study, said: 鈥淲ith all the current buzz around brain stimulation for altering brain activity, it鈥檚 important to understand who will benefit most from听this technique in the clinic.

鈥淧roblems with white matter structure are a feature of a range of different neurological conditions. Our study is a step towards more personalised use of brain stimulation, which will improve the outcomes using this technique, as well as reduce the number of people treated unnecessarily.鈥�

In the study, researchers looked at 24 healthy patients and 35 patients recruited predominantly from St Mary鈥檚 Hospital, part of Imperial College Healthcare NHS Trust, recovering from a moderate or severe traumatic brain injury (TBI). Participants performed a task inside an MRI scanner (see 鈥楾he Stop Signal Task鈥�听in sidebar) while receiving small amounts of electrical current through electrodes on the surface of the scalp or a placebo. They were unable to tell whether they were receiving brain stimulation or not. They found that healthy participants who received brain stimulation performed better in the task than when they did not receive the treatment. For patient with TBI, task performance in response to stimulation varied widely.

However, when they analysed MRI scans, they found that those participants with highly-connected white matter in the brain region being stimulated responded best to the treatment, and those who had damaged or less-connected regions of white matter showed less improvement. They also found that brain stimulation could partially reverse some of the abnormalities in brain activity caused by TBI.

The team cautions that while more work is needed to confirm the findings, it could mean brain stimulation might prove a useful treatment approach for other neurological conditions with abnormal brain activity as a feature, such as dementia.

鈥淲e found that people with听stronger听white matter connections in their听brain听had better improvement with stimulation,鈥� Dr Li explained. 鈥淭his might be an important reason why previous studies have found that听some people benefit from stimulation, whilst others don’t and means we can start using brain stimulation in a more personalised way.鈥�

According to the researchers, the study is limited in that in that they only investigated one type of cognitive behaviour and would need to be replicated in other types of behaviour to show if the findings apply more generally. In addition, they only stimulated one region of the brain, so they do not know whether the effects are specific to this region, or whether other regions can be stimulated. Dr Li explains the team will now focus on larger studies with more participants to investigate what other factors influence someone鈥檚 response to brain stimulation. They will also apply the technique to other conditions with听abnormalities in brain activity to see if they can alter activity and improve brain function.