Towards the Idea of Molecular Brains

Abstract

How can single cells without nervous systems perform complex behaviours such as habituation, associative learning and decision making, which are considered the hallmark of animals with a brain? Are there molecular systems that underlie cognitive properties equivalent to those of the brain? This review follows the development of the idea of molecular brains from Darwin’s “root brain hypothesis”, through bacterial chemotaxis, to the recent discovery of neuron-like r-protein networks in the ribosome. By combining a structural biology view with a Bayesian brain approach, this review explores the evolutionary labyrinth of information processing systems across scales. Ribosomal protein networks open a window into what were probably the earliest signalling systems to emerge before the radiation of the three kingdoms. While ribosomal networks are characterised by long-lasting interactions between their protein nodes, cell signalling networks are essentially based on transient interactions. As a corollary, while signals propagated in persistent networks may be ephemeral, networks whose interactions are transient constrain signals diffusing into the cytoplasm to be durable in time, such as post-translational modifications of proteins or second messenger synthesis. The duration and nature of the signals, in turn, implies different mechanisms for the integration of multiple signals and decision making. Evolution then reinvented networks with persistent interactions with the development of nervous systems in metazoans. Ribosomal protein networks and simple nervous systems display architectural and functional analogies whose comparison could suggest scale invariance in information processing. At the molecular level, the significant complexification of eukaryotic ribosomal protein networks is associated with a burst in the acquisition of new conserved aromatic amino acids. Knowing that aromatic residues play a critical role in allosteric receptors and channels, this observation suggests a general role of π systems and their interactions with charged amino acids in multiple signal integration and information processing. We think that these findings may provide the molecular basis for designing future computers with organic processors.

Technological Approach to Mind Everywhere: An Experimentally-Grounded Framework for Understanding Diverse Bodies and Minds

“…In general, larger selves (1) are capable of working toward states of affairs that occur farther into the future (perhaps outlasting the lifetime of the agent itself—an important great transition, in the sense of West et al (2015) , along the cognitive continuum); (2) deploy memories further back in time (their actions become less “mechanism” and more decision-making ( Balazsi et al, 2011 ) because they are linked to a network of functional causes and information with larger diameter); and (3) they expend effort to manage sensing/effector activity in larger spaces [from subcellular networks to the extended mind ( Clark and Chalmers, 1998 ; Turner, 2000 ; Timsit and Gregoire, 2021 )]. Overall, increases of agency are driven by mechanisms that scale up stress ( Box 1 )—the scope of states that an agent can possibly be stressed about (in the sense of pressure to take corrective action).…”

Virus-Induced Membrane Fusion in Neurodegenerative Disorders

“…Recent studies have shown that microtubules can generate action potential-like electrical oscillations, connecting these proteins to the higher brain functions such as memory and consciousness ( Ballatore et al., 2012 ). Indeed, the recent concepts, “cellular consciousness” and “molecular brains” suggest that cognition and information processing may occur at the cellular level ( Baluška et al., 2021 ; Timsit and Grégoire, 2021 ). Along these lines, neuronal ribosomal proteins and tubulin were showed to form CNS-like circuits with computation power, indicating the possibility of subcellular information processing ( Poirot and Timsit, 2016 ; Chudinova et al., 2019 ; Timsit and Bennequin, 2019 ; Fusco et al., 2021 ).…”

Fascial Nomenclature: Update 2022

“…DNA has and recognizes specific spectral signatures in order to create local and distant connections [ 77 ]. The specific response to DNA oscillations is then handled by the cell's microtubules and microfilaments, just like a chip or a micro-brain [ 77 - 79 ]. This view of biological behavior is based on quantum biology, where we move from the microscale to the nanoscale [ 79 ].…”