• A
  • A
  • A
  • ABC
  • ABC
  • ABC
  • А
  • А
  • А
  • А
  • А
Regular version of the site

The Shorter the Delay, the More Effective the Neurofeedback

The Shorter the Delay, the More Effective the Neurofeedback

© Anna Andreeva / 2nd year student, BA profile ‘Animation and Illustration’, HSE Art and Design School

HSE University scientists have for the first time in the world investigated the impact of delayed reinforcement signals in neurofeedback (NFB) training. They have experimentally proven that reducing the delay in feedback (decreasing feedback latency) can significantly increase the efficacy of training. This opens up new potential for the use of NFB for cognitive enhancement, self-regulation, and the treatment of a broad range of neurological disorders from anxeity and depression to epilepsy. The study was published in the Journal of Neural Engineering.

Neurofeedback (NFB) is a neuromodulation technology that allows a person to adjust the parameters of his or her own brain activity. Typically NFB uses electroencephalography (EEG) data reflecting changes in the potential of the electric field on the surface of the human head. EEG parameters are presented to the subject as, for example, a visual stimulus (column height on the screen, screen brightness) together with the task to change these parameters in the desired direction. By focusing on the NFB signal, the subject tries to remember the relationship between the parameter and their mental state. This allows a person to ‘feel’ the activity of their brain and learn how to control it. Often times such learning occurs subconsciously, i.e. without the use of any specific strategy.

Previous results from HSE University researchers have shown that in the majority of modern NFB systems the reinforcement signal lags behind the changes in neuronal activity, leading to ineffective learning and a wide dispersion of NFB therapy outcomes.

In order to provide access to the realm of small delays, the scientists developed a new mathematical method of filtering the EEG signal, allowing rapid estimation of the parameters of the rhythmic activity of the brain.  

‘This method gave us access to a previously unknown area of brain interaction with minimal latency in responses from the external system. It allows the brain to perceive an artificially created feedback loop as part of its own neural network. This is a qualitative leap that opens a new era in neurofeedback paradigm research,’ says Alexey Ossadtchi, Director of the Centre for Bioelectric Interfaces at HSE University.

This development allowed the scientists to conduct a ground-breaking study on the impact of feedback latency on the efficacy of neurofeedback training. Forty subjects were trained to increase the power of their own parietal alpha rhythm based on a feedback signal displayed on a computer screen.

Participants in the experiment were divided into four groups. Those in the first group received a feedback signal with the shortest achievable delay at the time of the test, 240 ms. HSE University scientists have now managed to achieve a feedback loop reinforcing instantaneous narrow-band rhythm power with a total delay of less than 110 ms. Feedback signals for the subjects in the second and third groups were artificially delayed by 250 and 500 ms respectively, and for the subjects in the fourth group the feedback was not at all associated with their brain activity.

It turned out that the subjects from the group with the minimum delay achieved a certain level of alpha rhythm power after fewer training sessions compared with subjects from the other groups. Moreover, the analysis of alpha rhythm power after training showed that only the subjects from the group with the minimum delay displayed a sustained increase in rhythm power. This result is particularly important, as achieving sustainable changes is the main goal of  the NFB therapy.


See also:

‘In the Blink of an Eye’ Statistics: People Estimate Size of the Set of Objects Based on Distance to Them

HSE University researchers Yuri Markov and Natalia Tiurina discovered that when people visually estimate the size of objects, they are also able to consider their distance from the observer, even if there are many such objects. The observers rely not only on the objects’ retinal representation, but also on the surrounding context. The paper was published in the journal Acta Psychologica.

Can the Brain Resist the Group Opinion?

Scientists at HSE University have learned that disagreeing with the opinion of other people leaves a ‘trace’ in brain activity, which allows the brain to later adjust its opinion in favour of the majority-held point of view. The article was published in Scientific Reports.

Researchers Expand the Capabilities of Magnetoencephalography

Researchers from the HSE Institute for Cognitive Neuroscience have proposed a new method to process magnetoencephalography (MEG) data, which helps find cortical activation areas with higher precision. The method can be used in both basic research and clinical practice to diagnose a wide range of neurological disorders and to prepare patients for brain surgery. The paper describing the algorithm was published in the journal NeuroImage.

How Modern Robots Are Developed

Today, neuroscience and robotics are developing hand in hand. Mikhail Lebedev, Academic Supervisor at HSE University’s Centre for Bioelectric Interfaces, spoke about how studying the brain inspires the development of robots.

Movement Recovery after Stroke Depends on the Integrity of Connections between the Cerebral Cortex and the Spinal Cord

A team of scientists, with the first author from the HSE University, were investigating which factors are the most important for the upper limb motor recovery after a stroke. The study is published in Stroke, the world's leading journal for cerebrovascular pathology.

Losing Money Multiple Times Causes Plastic Changes in the Brain

Researchers at the HSE Institute for Cognitive Neuroscience have shown experimentally that economic activity can actively change the brain. Signals that predict regular financial losses evoke plastic changes in the cortex. Therefore, these signals are processed by the brain more meticulously, which helps to identify such situations more accurately. The article was published in Scientific Reports.

HSE University Evaluated the Diagnostic Validity of the SARS Test

Researchers at the HSE University Centre for Language and Brain, in cooperation with a professor of neuropsychology from Lomonosov Moscow State University and specialists from the Centre for Speech Pathology and Neuro-rehabilitation, evaluated the diagnostic validity of the Standardized Assessment of Reading Skills in Russian (SARS) and checked whether the available normative data are current. The results of the study, the updated levels for reading speed, as well as the control levels for evaluating these indicators, were published in The Russian Journal of Cognitive Science. 

Russian Research Team Gains Deeper Insight into the Workings of the Human Brain during Group Problem Solving

A team of Russian researchers with the participation of a leading researcher at HSE University, Ekaterina Pechenkova, found that during group problem solving the components of the social brain are co-activated, but they do not increase their coupling during cooperation as would be suggested for a holistic network. The study was published in Frontiers in Human Neuroscience.

Neural Networks Can Now Make Personality Judgments Based on Our Photographs

Many people are able to recognize the personality traits of the person they are talking to by their facial features. Experts in non-verbal communication can do this even with a photograph. But is it possible to teach artificial intelligence to do the same?

Attention and Atención: How Language Proficiency Correlates with Cognitive Skills

An international team of researchers carried out an experiment at HSE University demonstrating that knowledge of several languages can improve the performance of the human brain. In their study, they registered a correlation between participants’ cognitive control and their proficiency in a second language.