Posts tagged brain signals
Articles and news from the latest research reports.
Two minds are better than one
Scientists at the Essex have been working with NASA on a project where they controlled a virtual spacecraft by thought alone.
Using BCI (brain-computer interface) technology, they found that combining the brain power of two people could be more accurate in steering a spacecraft than one person. BCIs convert signals generated from the brain into control commands for various applications, including virtual reality and hands-free control.
Researchers at Essex have already been undertaking extensive projects into using BCI to help people with disabilities to enable spelling, mouse control or to control a wheelchair. The research involves the user carrying our certain mental tasks which the computer then translates into commands to move the wheelchair in different directions.
The University has built-up an international reputation for its BCI research and is expanding its work into the new area of collaborative BCI, where tasks are performed by combining the signals of multiple BCI users.
The £500,000 project with NASA’s Jet Propulsion Lab in Pasadena, California, involved two people together steering a virtual spacecraft to a planet using a unique BCI mouse, developed by scientists at Essex.
Using electroencephalography (EEG), the two users wore a cap with electrodes which picked up different patterns in the brainwaves depending on what they were focusing their attention on a screen – in this case one of the eight directional dots of the cursor. Brain signals representing the users’ chosen direction, as interpreted by the computer, were then merged in real time to produce control commands for steering the spacecraft.
As Professor Riccardo Poli, for the University’s School of Computer Science and Electronic Engineering, explained, the experiment was very intense and involved a lot of concentration. With two people taking part in the test, the results were more accurate as the system could cope if one of the users had a brief lapse in concentration.
Analysis of this collaborative approach showed that two minds could be better than one at producing accurate trajectories. Combining signals also helped reduce the random “noise” that hinders EEG signals, such as heartbeat, breathing, swallowing and muscle activity. “When you average signals from two people’s brains, the noise cancels out a bit,” added Professor Poli.
Professor Poli said an exciting development for BCI research in the future relates to joint decision making, where a physiological signal, like pressing a button, and brain activity can be combined to give a superior result. “It is like measuring someone’s gut feeling,” added Professor Poli.
(Source: essex.ac.uk)
Brain activity study lends insight into schizophrenia
Magnetic fields produced by the naturally occurring electrical currents in the brain could potentially be used as an objective test for schizophrenia and help to better understand the disease, according to new research published today.
A team of researchers from Plymouth and Spain have used the non-invasive magnetoencephalogram (MEG) technique to find two spectral features that are significantly different in schizophrenia patients compared to healthy control subjects.
Furthermore, they found that there were four spectral features in the brain signals of schizophrenia patients that changed with age compared to healthy control subjects, suggesting that schizophrenia affects the way in which brain activity evolves with age.
The study has been published today, Thursday 31 January, in the journal Physiological Measurement.
Schizophrenia is a serious psychiatric disorder, usually starting in late adolescence, which is characterised by a range of positive and negative symptoms, including hallucinations, delusions, paranoia, cognitive impairment, social withdrawal, self-neglect and loss of motivation and initiative.
It has no objective test and is currently diagnosed by clinicians who assess patients using a defined set of criteria.
Lead author of the study Dr Javier Escudero said: “At present, there is no blood, cerebrospinal fluid, brain imaging or neurophysiological test for schizophrenia in routine clinical practice. The diagnosis relies on the interpretation of symptoms and clinical history according to consensus criteria.
"The advent of an objective marker for schizophrenia would significantly facilitate the diagnosis and offer a better understanding of the neurobiological basis of the disease."
In this study, the frequency spectrum of the MEG background activity was analysed in 15 schizophrenia patients with positive symptoms and 17 age-matched healthy control subjects.
A range of spectral features from the MEGs were analysed to provide a holistic view of the brain activity of each subject. The MEG produced 148 values for each subject, which were subsequently divided into five different groups representing different parts of the brain, and were statistically analysed.
The researchers also investigated whether the spectral features could be used to distinguish between schizophrenia patients and the healthy controls. They showed that they were able to classify patients with 71 per cent accuracy.
"The long-term vision is to develop a low-cost, non-invasive and objective test to aid the diagnosis of this and other brain diseases. The magnetoencephalogram is able to provide very detailed information about the brain activity; however, it is expensive. Therefore, we aim to transfer these developments to electroencephalogram recordings in the future, as this technique meets those requirements of reduced cost, high availability and non-invasiveness," continued Dr Escudero.
(Image: Shutterstock)
“Doctor” or “Darling”: The Subtle Differences of Speech
Human speech comes in countless varieties: When people talk to close friends or partners, they talk differently than when they address a physician. These differences in speech are quite subtle and hard to pinpoint. In a recent special issue of the journal Frontiers in Human Neuroscience, Johanna Derix, Dr. Tonio Ball, and their colleagues from the Bernstein Center and the University Medical Center in Freiburg report that they were able to tell from brain signals who a person was talking to. This discovery could contribute to the further development of speech synthesizers for patients with severe paralysis.
In contrast to the experimental research common in human neuroscience, the scientists studied natural, non-experimental behavior. Patients who, for medical reasons, had electrodes implanted underneath their skull allowed their brain activity to be recorded during daily life in the hospital. The Freiburg researchers compared data recorded during natural conversations that the patients had with their physicians and their life partners. They found pronounced differences in the anterior temporal lobe, a brain area well known for its significance in social interaction. Several components of neural signals that are detectable on the brain surface can convey such information.
“This study is only the first step towards elucidating the neural basis of human everyday behavior,” explains the neuroscientist and physician Tonio Ball. “Such investigations will become especially important in developing new neurotechnological treatment options for patients with impaired motor and language functions that work in real life situations.” The restoration of speech production becomes necessary in some forms of neurological diseases and chronic paralysis. A computer could synthesize speech for patients suffering from such conditions by using their brain signals. Information on who the patient is addressing could help the device to select the degree of formality – and to prevent it from calling the doctor “darling.”