Self Comes to Mind

exemplars are more independent and clearly separate from each other.
    The cerebral cortices are evolutionarily more recent than the nuclei. They are all distinguished by their two-dimensional sheathlike structure, which confers upon some of them detailed map-making abilities. But the number of layers in a cortex varies from a mere three (for old-vintage cortices) to six (for more recent vintages). The complexity of the circuitry within and across those layers varies as well. The overall location in the whole brain volume is also functionally telling. In general, very modern cortices occur at and around the point at which the major sensory pathways—e.g., auditory, visual, somatosensory—enter the cerebral cortex mantle and are thus connected with sensory processing and map-making. In other words, they belong to the “early sensory cortex” club.
    Motor cortices also have varied vintages. Some motor cortices are quite old and small, again located at the midline in the anterior cingulate and supplementary motor regions, clearly visible on the internal (or medial) surface of each cerebral hemisphere. Other motor cortices are modern and structurally sophisticated and occupy a sizable territory on the external surface of the brain (the lateral surface).
    What a given region ends up contributing to the overall business of the brain depends significantly on its partners: which talks to the region and which is talked back to, specifically, which regions project their neurons to region X (thus modifying the state of region X) and which regions receive projections from region X (thus being modified by its output). A lot depends on where region X is located within the network. Whether region X has map-making abilities is another important factor in its functional role.
    Mind and behavior are the moment-to-moment results of the operation of galaxies of nuclei and cortical parcels articulated by convergent and divergent neural projections. If the galaxies are well organized and work harmoniously, the owner makes poetry. If not, madness ensues.
AT THE INTERFACES BETWEEN THE BRAIN AND THE WORLD
    Two kinds of neural structures are located at the border between the brain and the world. One points inward , the other outward . The first neural structure is made up of the sensory receptors of the body’s periphery—the retina, the cochlea in the inner ear, the nerve terminals in our skin, and so forth. These receptors do not receive neuron projections from the outside, at least not naturally, although neuronlike electrical inputs from prosthetic implants are changing this situation. They receive physical stimuli instead—light, vibration, mechanical contact. Sensory receptors initiate a chain of signals from the body’s border to inside the brain, across multiple hierarchies of neuron circuits that penetrate deeply into the brain territories. But they don’t just move up like water in a pipe system. At every new station they undergo processing and a transformation. In addition, they tend to send signals back to where the inbound projection chains started. These understudied features of brain architecture probably have great significance for certain aspects of consciousness.
    The other kind of border point occurs where the outward projections from the brain end and the environment begins. The chains of signals arise within the brain but end up either releasing chemical molecules into the atmosphere or connecting to muscular fibers in the body. The latter enables us to move and speak, and that is where the principal outward chains terminate. Beyond the muscle fibers there lies direct movement in space. In earlier stages of evolution, the release of chemical molecules at the membrane or skin border played important roles in the life of an organism. It was an important means of action. In humans, this facet remains understudied, although the release of pheromones is not in doubt.
    One may conceptualize the brain as a progressive elaboration of what began as a simple reflex arc: neuron NEU senses object OB and signals to neuron ZADIG, which projects to muscle fiber MUSC and causes movement. Later in evolution a neuron would be added to the reflex circuit, in between NEU and ZADIG. This is an interneuron , and let us call it INT; it behaves such that the response of neuron ZADIG is no longer automatic. Neuron ZADIG responds, for example, only if neuron NEU fires all its guns upon it and not if neuron ZADIG receives a weaker message;