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Research

Researchers Explain the Neural Mechanisms that Enable Conscious Experience

Recently, there has been convergence of thought by researchers in the fields of memory, perception, and neurology that the same neural circuitry that produces conscious memory of the past not only produces predictions of the future, but also conscious perception of the present.

In a new perspective in the Journal of Cognitive Neuroscience, researchers explain that although our conscious perception appears to simply mirror the external world, due to neural processing delays this intuitive feeling must be wrong. Instead, unconscious perceptual mechanisms represent a timeline that is then consciously remembered. Because the default mode network, along with the frontoparietal control and salience networks, are critical for simulation and memory, they are also critical for consciousness.

“The same simulation processes are used whether we are consciously remembering the past, experiencing the present or imagining the future. Perceptual mechanisms represent an ongoing, editable, ‘best estimate’ of our past, present, and future. There is no hard boundary between conscious perception and memory at milliseconds to seconds timescales,” explains corresponding author Andrew Budson, MD, professor of neurology at Boston University Chobanian & Avedisian School of Medicine.

Budson, who also is chief of cognitive behavioral neurology and director of the Center for Translational Cognitive Neuroscience at the Veterans Affairs (VA) Boston Healthcare System, collaborated with Hinze Hogendoorn, PhD, professor of neuroscience at Queensland University of Technology and Donna Rose Addis, PhD, professor psychology at the University of Toronto.

Previously, Budson published an opinion paper describing the Memory Theory of Consciousness (in the journal Cognitive and Behavioral Neurology), which suggests that our conscious perceptions, decisions, and actions are actually memories of prior unconscious sensations, decisions and actions. Hogendoorn, an expert on the timing of conscious perception, argues that at milliseconds to seconds timescales, “there is no hard natural boundary between perception and memory.” Addis, who studies memory using functional magnetic resonance imaging, suggests that memory, imagination and even our experience of the present are all simulations created by our brain.

The synthesis of their combined theories can explain many mysteries of consciousness including its purpose, anatomy and physiology. “If our synthesis is correct, then we now know the purpose of consciousness, which is the purpose of explicit memory—to use prior information to understand the present moment, imagine possible futures, and plan accordingly,” adds Budson. The theory also suggests that the anatomy and physiology of consciousness is the anatomy and physiology of explicit memory, which Budson argues is the entire cerebral cortex.

According to the researchers, the new synthesis also complements other theories of consciousness, including global neuronal workspace and predictive processing theories. Budson notes that, “this novel synthesis suggests that many major theories of consciousness may be describing its various parts.”