New paper published in Neuron by research team of the Max-Planck Institute for Human Development in Berlin, draws attention to a somewhat neglected feature of resting state brain activity- the neural noise.
While the majority of scientific studies investigating perception and cognition have focused on identifying and interpreting “the signal in the noise” in physiological data, novel research, summarised in the paper, highlights the importance of neural noise. The German scientists provide an exciting overview of recent EEG and fMRI studies indicating that increased neural variability (noise) is a prerequisite for richer perception and for cognitive, emotional and behavioural flexibility. Furthermore, they suggest that the ability to increase and decrease the signal-to-noise ratio in the brain in a task-dependant manner, is critical for individual’s peak performance across multiple cognitive domains.
The brain is not the only organ, in which functional signal variability represents a feature of optimal performance. Likewise, the variance in the oscillations and the pace of the human heart, in relation to respiration and parasympathetic and sympathetic neural activation, has been established as an index of emotional and autonomic nervous system flexibility, and key to mental and physical resilience.
The variability of the spontaneous neural activity in biological systems and the ability to shift seamlessly between the states of low (rhythmic, organised, high signal-to-noise) and high (variability, noise) entropy states seems critical for the ability of a system to evolve and adapt.
Interestingly, this spontaneous variability seems to decrease with age. Fortunately, the availability of non-invasive brain stimulation (NIBS) techniques allows us to introduce noise in the system and potentially influence this process of decline.
Reference: Leonhard Waschke, Niels A. Kloosterman, Jonas Obleser, Douglas D. Garrett. Behavior needs neural variability. Neuron, 2021; DOI: 10.1016/j.neuron.2021.01.023