Abstract

The vast number of neurons in the brain are ceaselessly engaged in spontaneously generated activity in virtue of interactions between those. It is in the background of this intrinsic activity that the brain responds to signals from the environment and from endogenous signals received by way of active mental processes. This spontaneous activity persists in the `resting state' and is modulated by evoked signals resulting from task-induced activity. The two together generate an ongoing process of self-organization in the brain whereby dynamic excitation patterns are set up and correlated with one another in neuronal aggregates of diverse population size in an intricately nested hierarchy. These correlated patterns constitute distributed models of reality, based on which the brain generates expectations, plans, and predictions relating to the dynamically evolving world that we all are embedded in. The process of neuronal self-organization provides the basis for the emergence of a structured mind exhibiting an exquisite functional complexity. Generally speaking, mental (and, in particular, psychological) processes are based on large scale (`macroscopic') neuronal networks, while microscopic and mesoscopic neuronal populations constitute the `substratum' of the mind, where elementary and tiny bits of experience are represented so as to act as atomic ingredients in the more complex processing of compositely constituted information involved in mental activities. Processes in the microscopic and mesoscopic neuronal aggregates occur on relatively short spatial and temporal scales while those in macroscopic networks are slower and distributed across brain regions. The large scale networks operate near the `edge of instability', which means that these networks, taken together, form a system close to criticality---this is what makes the mind possessed of its remarkable fluidity. The neuronal aggregates themselves are in a constant state of flux, with groups of neurons constantly entering and leaving larger aggregates, and with neurons being simultaneously operative in the functioning of more than one aggregates at a time. In the backdrop of this enormous complexity, the operations of the mind constitute a complementary description of the brain-mind complex to those of the neuronal populations---neither of the two is reducible to the other. In other words, the functioning of the mind is not determinable in terms of the activities of the neuronal populations. The `substratum of the mind', made up of microscopic and mesoscopic populations of neurons, in addition to providing the hinterland in which latent operations supporting all mental processes are enacted, is involved more directly with representations of elementary concepts, with distributed memory (in a broad sense), and with heuristics of an elementary and atomic nature that help us in making vast numbers of `decisions' of a similarly elementary nature.