Self Comes to Mind

originates, there is a rich collection of other nuclei that includes those involved in the management of internal body states: the locus coeruleus, the ventral tegmental nuclei, and the raphe nuclei, respectively responsible for the release of norepinephrine, dopamine, and serotonin in certain sectors of the cerebral cortex and basal forebrain. The projections from these nuclei bypass the thalamus.
    Among the nuclei involved in body state management, we find the nucleus tractus solitarius (NTS) and the parabrachial nucleus (PBN), whose significance was discussed in Chapters 3, 4, and 5 relative to the creation of a first line of bodily feelings, the primordial feelings. The upper brain stem also includes the nuclei of the periaqueductal gray (PAG), whose activity results in the behavioral and chemical responses that are part and parcel of life regulation and, as part of that role, execute the emotions. The PAG nuclei are closely interlocked with those of the PBN and the NTS and also with the deep layers of the superior colliculi, which are likely to play a coordinating role in the construction of the core self. This complicated anatomy tells us that while the classical nuclei and the ascending activating systems are no doubt associated with wake and sleep cycles, the remainder of the brain-stem nuclei participate in other equally important functions relevant to consciousness, namely, the housing of the standards for biological value; the representation of the organism’s interior on the basis of which the protoself is assembled and primordial feeling states are generated; and the critical first stages in the construction of the core self, which has consequences for the governance of attention. 4
    In brief, reflection on this profusion of functional roles reveals a shared dedication to the management of life. But the idea that the work of these nuclei is confined to the regulation of viscera, metabolism, and wakefulness does not do justice to the results they achieve. They manage life in a far broader way. This is the neural home of biological value, and biological value has a pervasive influence throughout the brain, in terms of structure and operations. In all likelihood, this is the place where the process of making mind begins, in the form of primordial feelings, and it is apparent that the process that makes the conscious mind a reality, the self, also originates here. Even the coordinating efforts of the deep layers of the superior colliculi get into the act and lend a hand.
THE THALAMUS
    Consciousness is often described as the result of massive integration of signals in the brain, across many regions; in that description, the role of the thalamus is most prominent. Without a doubt the thalamus contributes importantly to the creation of the background fabric of the mind and to the endgame we call the conscious mind. But can we be more specific about its roles?
    Like the brain stem, the thalamus contributes to all components of the conscious mind triad. One set of thalamic nuclei is essential for wakefulness and bridges brain stem to cortex; another brings in the inputs with which cortical maps can be assembled; the remainder assists with the sort of integration without which a complex mind is not conceivable, let alone a mind with a self in it.
    I have always resisted venturing into the thalamus, and I am even more cautious today. What little knowledge I have of the huge collection of thalamic nuclei, I owe to the very few experts on this structure. 5 Still, some of the roles played by the thalamus are not in question and can be reviewed here. The thalamus serves as a way station for information that’s collected from the body and destined for the cerebral cortex. This includes all the channels that ferry signals about the body and about the world, from pain and temperature to touch, hearing, and vision. All signals bound for the cortex stop at thalamic relay nuclei and change into tracks that take them to their destinations in varied cities of the cerebral cortex. Only smell manages to escape the thalamic attractor and wafts to the cerebral cortex, as it were, via nonthalamic channels.
    The thalamus also deals with the signals required to wake up the entire cerebral cortex or put it to sleep—this is done by neuron projections from the reticular formation that I mentioned earlier. Their signals change paths at the intralaminar nuclei, and the PMCs are a major destination.
    But no less importantly—and far