MIT News breed · Wetenschap

New Theory: Brain Uses Analog Computations via Traveling Waves for Cognition and Consciousness

A new theory from MIT scientists suggests that the brain utilizes traveling waves of rhythmic neural activity to coordinate neural networks through analog computations, explaining how cognition and consciousness arise. This model expands on the traditional 'circuit' metaphor by incorporating the dynamic role of brain waves.

The brain's existing circuits and synapses provide the foundation for memory and goals, but they are too slow for rapid, adaptive responses to the environment. Instead, a faster control system is needed to coordinate millions of neurons. Brain waves, synchronized rhythmic fluctuations of neurons, are proposed to fulfill this crucial service.

Unlike digital circuits that process information sequentially, analog computation, facilitated by wave interference, allows for parallel processing. The theory posits that the brain leverages its physical properties, specifically these traveling waves, to perform computations efficiently and locally.

This theory has implications for clinical treatments, as brain waves can be manipulated non-invasively. Research is already underway to study brain wave dynamics in conditions like autism, suggesting potential therapeutic avenues.

The theory builds on the concept of 'mixed selectivity,' where neurons participate in multiple networks simultaneously. Brain waves are seen as the organizing principle for these neural ensembles, with different frequencies governing various cognitive processes like working memory and sensory information processing.

Specifically, slower alpha and beta waves, representing memories and goals, regulate faster gamma waves, which handle incoming sensory data. Synapses store these representations, while wave dynamics determine which ones are active. Emerging research also indicates that waves can directly influence neural spiking through rapid electric field-mediated processes.

Alpha/beta waves exert control spatially and temporally, acting like 'mobile stencils' that dictate where and when sensory information is processed and which neuron ensembles are involved. This 'spatiotemporal computing' allows for analog computations where waves intersect and combine.

The researchers aim to find direct evidence of these analog computations within brain wave patterns. Consciousness is theorized to emerge when these dynamic wave patterns create an organized, globally integrated state within the cortex, linking widespread activity.

Studies on general anesthesia show that disrupting brain wave dynamics leads to unconsciousness, regardless of the specific drugs used. This suggests that consciousness relies more on the integrity of large-scale wave organization than on specific cellular components. The brain's efficiency in organizing information through waves is seen as a key evolutionary advantage.

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