How the Brain Works

FIGURE 1.1. The anatomy of a cell. Illustration copyright 2004 by James P. McCahill. Used with permission. 

The postsynaptic neuron receives the neurotransmitter when the neurotransmitter engages a receptor site on the neuron s cell membrane. Each type of neurotransmitter will react with one specific type of receptor site and no other, similar to a lock and key. But it would not do to just let neurotransmitters sit there in the synapse causing unending activity, so there are other components in presynaptic neurons that take the extra neurotransmitters in a particular area back into the cell (this is called reuptake). Sometimes the neurotransmitters that have been taken back are broken down in the presynaptic neuron (by enzymes, such as monoamine oxidase, or MAO), and then are recycled in the vesicles for later use. There are at least 40 different chemicals that have been shown to act as neurotransmitters some of the most common are listed in Table 1.1. 

Usually excitatory, except for some parasympathetic nerve endings where it is inhibitory (such as the effect on the heart by the vagus nerve). Secreted by many neurons, including those in the motor area of the brain, basal ganglia, skeletal muscle motor neurons, all preganglionic autonomic nervous system neurons, all postganglionic parasympathetic neurons, and some postganglionic sympathetic neurons. 

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Perhaps it is not surprising to find that our knowledge of how the brain works and where defects that lead to abnormal behaviour can arise is so deficient. The approach to understanding the biochemical basis of psychiatric disease is largely based on the assumption that the brain is chemically homogeneous, which is improbable Nevertheless, there has been some success in recent years in probing the changes that may be... 

Basic neuroscience information on how the brain works and how drugs affect the brain. 

In this section, we discuss some basic concepts about how the brain works and how psychotropic medications affect it. We believe you should have some understanding of these issues for four reasons ... 

A neural network is a piece of hardware or software (or a combination of the two) that simulates what we think we know about how the brain works. The operative word is "think" to say that such models do things exactly as the brain does would be much too presumptuous at this time, as there are still a great many mysteries concerning the brain. To avoid any implied presumption, some researchers in this field prefer terms like parallel distributed processors, connectionist systems, or collective decision circuits. 

Source From Dubin, How the Brain Works, note 48. 

Kotulak, R. (1997). Inside the brain Revolutionary discoveries of how the brain works. Kansas City, MO Andrews McMeel. 

New York Times, September 17, 2007). Yet, we are making progress. It is a lot easier to study how drugs affect the brain than to discover how the brain works. 

Over a century before, Marie Curie had expressed her hope that scientific knowledge would someday result in a decrease in violence, war, and poverty. We do not need to know how the brain works to be able to learn how drugs affect brain chemistry. 

In vivo MR has been extensively used in the study of the human brain, its fiinctions and metabolism. MRI has a significant role to play in our understanding of how the brain works. In the last few years the most interesting application of MRI is the construction of functional maps of the brain (functional MRI, fMRI). In response to brain activation, an increase in the proportion of oxyhemoglobin with respect to the deoxyhemoglobin takes place. 

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