The Map that Will Change the World

The central form of information transmission today is undoubtedly the internet; this bodiless network has the ability to create, strengthen, and destroy the connections that comprise it. This is not so different from our brains. Think of logging on to Google and typing in a search for brain. This single input elicits a response from many different web pages with a close match to the search term. At the top are the sites with stronger connections to the search “brain” and those at the bottom have the weaker connections. This order can be changed. As internet traffic increases to a certain site its position moves higher in the list. The brain performs a similar search after we hear a word. A “meter” might bring to mind a device for measurement, such as a parking meter or thermometer, or a unit of measure that equals 100 centimeters or even the rhythmic structure of poetry. Repeated exposure to a different term can lead to changes in what meaning the word is initially associated with due to increased neuronal activity and strengthening the relationship.

Another search for, say, “nervous system” may bring up some of the same web pages because the terms nervous system and brain are connected. These new pages will each respond to their own input and suddenly this simple network is complex. If we make a simple circuit of three neurons in which each have five connections there are a total of 15 synapses that can be arranged in any of 120 different connection patterns. A typical adult neuron makes about 7,500 synapses with any number of other neurons, yet in the adult brain there are billions of neurons to be analyzed. The formation of a collaboration named the Human Connectome Project (HCP) has set out to map every synapse in the human brain. This means that the location and number of connections between any two neurons will be identified. Many believe the big questions in neuroscience today (i.e. How do memories form?) can only be resolved through connectomic analysis, and while the project is currently in its formative stages new imaging techniques are being developed to speed up the process. The figure (below) shows a general map of the fiber tracts in the brain that has been generated, but the resolution power is not reliable enough to be considered 100% accurate. Even though completion is far off we don’t have to wait to make use of the findings. Websites such as Elsevier’s Brain Navigator (http://www.brainnav.com/home;jsessionid=E2CB717544FCA387D151968247BBEBD7) allow anyone to look at brain structures or view the whole brain in three dimensions. These tools are now an invaluable asset to many researchers due to the increased accuracy and functionality over printed atlases. New findings, such as, gene expression patterns, can be uploaded to these programs creating a growing database that has the ability to enlighten anyone from a high school student to a seasoned Neuroscientist.