From Axons to Identity: Neurological Explorations of the Nature of the Self (Norton Series on Interpersonal Neurobiology) by Feinberg Todd E

Author:Feinberg, Todd E. [Feinberg, Todd E.]
Language: eng
Format: mobi
Publisher: W. W. Norton & Company
Published: 2011-04-11T04:00:00+00:00

CHAPTER FIVE

The Neural Structure of the Self

WHILE I HAVE thus far focused on clinical neuropathologies in order to examine the critical issue of how the brain creates the self, there are many other interesting aspects to this question that transcend the clinical conditions I have described. We will turn now to the larger model of how the brain is organized to make the creation of the self possible, and as in the hierarchical development of the self that we have examined so far, the relationship between the brain and the self can only be understood as the result of the hierarchical patterns of the growth of neural systems. In subsequent chapters we will also explore some of the most interesting yet unsolved puzzles of modern neuroscience, such as the relationship between the brain, the self, and consciousness and how the brain creates mental unity.

The human brain is the most complex structure on earth. Indeed, it is somewhat ironic that the very structure that enables us to think great thoughts is itself so difficult to understand. (How the billions of neurons within the brain coordinate their activity to create a unified self is one of the great remaining scientific mysteries—a problem I will return to later.) This complexity makes it difficult to describe in broad strokes the general patterns that make the workings of the brain comprehensible. Since the late 1980s, however, there has been enormous progress in our understanding of the neurobiology of the self. In this chapter I will examine some basic evolutionary trends and neuroanatomical principles that order the brain and attempt to integrate recent theories into a general model of the neural basis of the self.

As the human brain evolved, enabling it to accomplish its increasingly difficult tasks, the structure of the brain developed in similarly complex ways that we can observe today. In order to create a blueprint to deepen our understanding of the relationship between the brain and the self, I propose a model that approaches the nervous system from the standpoint of two organizational trends that help us understand the shape the brain takes and how that shape relates to its ability to create the self.

If we think of the central nervous system, including the brain and the spinal cord, as something like a tree, the first trend we can observe is its cross-sectional organization, as when, for example, one examines the radially arranged growth rings in the tree’s trunk. In the second major pattern, a tree may also be examined from the “bottom-up,” taking into consideration its hierarchical organization from its roots to its leaves. In a similar fashion, the nervous system demonstrates increasing complexity as it extends from the lower levels of the nervous system to the most evolved and highest levels. As we shall see, both of these trends, the radially arranged medial–lateral trend, and the longitudinally organized caudal–rostral trend, are essential to the development and functioning of the neural substrate of the self.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.