Long memories in brain activity explain streaks in individual behaviour

(Medical Xpress)—Even with a constant task, human performance fluctuates in time-scales from seconds to minutes in a fractal manner. In a recent study a Finnish research group found that the individual variability in the brain dynamics as indexed by the neuronal scaling laws predicted the individual behavioral variability and the conscious detection of very weak sensory stimuli. These data indicate that individual neuronal dynamics underlie the individual variability in human cognition and performance. Results may also have a strong impact in understanding the neuronal mechanism of neuropsychiatric diseases in which behavioral dynamics are abnormal.

Human performance in cognitive tasks varies from moment-to-moment so that the similar behavioral performance is clustered into streaks. The neuronal dynamics underlying this behavioral variability has remained unknown.

Similar scale-free and power-law distributed "avalanche dynamics" is observed in many natural systems such as sand piles, earthquakes, gene regulation, and also brain activity. However, the functional significance of the neuronal scale-free behavior has remained unknown. It is also unclear whether it is just epiphenomena without any further significance.

"We investigated whether the individual variability in the scaling-laws governing the detection of auditory and presented in the threshold of detection could be predicted by the variability in the neuronal scaling laws," explains Matias Palva, project leader in the Neuroscience Center of the University of Helsinki, Finland.

The researchers used magneto- and electroencephalography to record non-invasively human brain activity during the task performance. They found that both the behavioral and neuronal dynamics were characterized by scale-free dynamics. Individual variability in the neuronal scaling laws predicted the individual scaling laws in behavioral performance.

"These results suggest that the individual behavioral and psychophysical variability in task performance is largely a result of the inherent variability in the individual ," says project leader Satu Palva.

More information: PNAS doi: 10.1073/pnas.1216855110

Related Stories

Watching neurons learn

Apr 26, 2012

What happens at the level of individual neurons while we learn? This question intrigued the neuroscientist Daniel Huber, who recently arrived at the Department of Basic Neuroscience at the University of Geneva. During his ...

Is too much brain activity connected to Alzheimer's disease?

Aug 16, 2012

High baseline levels of neuronal activity in the best connected parts of the brain may play an important role in the development of Alzheimer's disease. This is the main conclusion of a new study appearing in PLoS Computational Bi ...

Recommended for you

Surprising new role for calcium in sensing pain

20 hours ago

When you accidentally touch a hot oven, you rapidly pull your hand away. Although scientists know the basic neural circuits involved in sensing and responding to such painful stimuli, they are still sorting ...

Neurons in human skin perform advanced calculations

Sep 01, 2014

Neurons in human skin perform advanced calculations, previously believed that only the brain could perform. This is according to a study from Umeå University in Sweden published in the journal Nature Ne ...

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

thingumbobesquire
1 / 5 (1) Feb 13, 2013
Attention span (and attention directedness) is determined by factors that are outside the realm of biophysics per se. These factors have to do with cognitive resonance with idea content. This is what fundamentally differentiates mere physical brain functions from the culturally determined category of mind. In this regard, attention can be maintained on appropriately defined subject matter across generations.