Self Comes to Mind

enabled detailed image-making, expanded memory capacity, imagination, reasoning, and eventually language. Now comes the big problem: notwithstanding the anatomical and functional expansion of the cerebral cortex, the functions of the brain stem were not duplicated in the cortical structures. The consequence of this economic division of roles is a fatal and complete interdependence of brain stem and cortex. They are forced to cooperate with each other.
    Brain evolution was faced with a major anatomo-functional bottleneck, but natural selection predictably solved it. Given that the brain stem was still being asked to guarantee the full scope of life regulation and the foundations of consciousness for the entire nervous system, a way had to be found of ensuring that the brain stem influenced the cerebral cortex and , just as important, that the activities of the cerebral cortex influenced the brain stem, most critically, of course, when it came to the construction of the core self. This is all the more important when we think that most external objects exist as images only in the cerebral cortex and cannot be fully imaged in the brain stem.
    This is where the thalamus came to the rescue, as the enabler of an accommodation. The thalamus accomplishes a dissemination of signals from the brain stem to a widespread territory of the cortical mantle. In turn, the hugely expanded cerebral cortex, both directly and with the assistance of subcortical nuclei such as those in amygdalae and basal ganglia, funnels signals to the small-scale brain stem. Maybe in the end the thalamus is best described as the marriage broker of the oddest couple.
    The brain-stem–cortex mismatch is likely to have imposed limitations on the development of cognitive abilities in general and on our consciousness in particular. Intriguingly, as cognition changes under pressures such as the digital revolution, the mismatch may have a lot to say about the way the human mind evolves. In my formulation the brain stem will remain a provider of the fundamental aspects of consciousness, because it is the first and indispensable provider of primordial feelings. Increased cognitive demands have made the interplay between the cortex and brain stem a bit rough and brutal, or, to put it in kinder words, they have made the access to the wellspring of feeling more difficult. Something may yet have to give.
    I said it would be foolish to take sides and favor one of the three divisions in the process of the making of consciousness. And yet one has to agree that the brain-stem component has a functional precedence, that it remains an entirely indispensable part of the puzzle, and that, for that very reason as well as for its modest size and jam-packed anatomy, it is the most vulnerable to pathology among the big three divisions. This much needs to be said, if only because in the wars of consciousness the cerebral cortex tends to get the upper hand.
From the Ensemble Work of Large Anatomical
Divisions to the Work of Neurons
     
    Up to this point, I have attempted to explain the emergence of a conscious mind largely from the perspective of components that can be identified with the naked eye, including the small nuclei of the brain stem and thalamus. What the naked eye does not see, however, is the millions of neurons that make up the networks or systems within those structures, nor the numerous small groupings of such neurons that contribute to the overall effort of making a mind with a self. The ensemble work of the large anatomical divisions is built on the ensemble work of components of gradually smaller scale, all the way down to small circuits of neurons. In this downward anatomical trend, there are smaller and smaller regions of the cerebral cortex, along with their retinues of cable work connecting them to other brain sites; there are smaller and smaller nuclei wired in particular ways to other nuclei and to regions of the cortex; last, at the bottom of the hierarchy, we find the small neuron circuits, the microscopic building blocks whose momentary spatial patterns of activity create minds. The conscious mind is built from the brain’s nested, hierarchical componentiality.
    It is generally assumed that the firing of neurons linked by synapses within microscopic circuits gives rise to the basic phenomena of mind-making, conveniently called the “protophenomena” of cognition. It is also thought that scaling up a large number of such phenomena results in the making