SYNAPTIC DARWINISM

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I teach an undergraduate course at Stony Brook, called "From Synapse to Circuit: Selforganization of the Brain". This course presents some of the basic ideas of contemporary neuroscience in a more quantitative, and abstract, form than is commonly encountered in introductory neurobiology courses. The aim of the course is to sketch how the special properties of biological molecules (such as ion channels), synapses, neurons and the circuits they comprise lead to the extraordinary features of "mind": complex adaptive behavior, knowledge, understanding, emotion, sleep, dreams, language, even consciousness and "soul". The underlying idea is that the special properties of synapses, arising from the molecules of which they are composed, endow the brain, by a process of "selforganization", with unexpected features, such as "mind". "Selforganization" refers to the way that many complex systems, composed of large numbers of relatively simple interacting parts, behave in unexpected ways when the rules governing the interaction of the parts have particular forms. The course does not aim to be comprehensive, partly because the subject is too vast, and partly because neuroscientists (especially me) do not yet completely understand the subject. The following is the summary of the course that appears in the Stony Brook undergraduate handbook:

"BIO 338 "From Synapse to Circuit: Selforganisation of the Brain"

Exploration of basic neural and synaptic mechanisms and the operation of representative brain circuits, using both theoretical approaches and experimental evidence. Particular attention will be given to Hebb’s Rule ("cells that fire together, wire together"), its cellular basis, its consequences for circuit selforganisation, and its limits. The course is aimed at anyone with curiosity about the brain, who is willing to tackle a range of reading, including original research papers. A solid background in a mathematical, physical or biological science is desirable, though the course will be largely selfcontained.

The 2005 Syllabus for the course can be seen by clicking here.

 

 

Note on the Hebb Synapse.

An important unifying concept of the course is the "Hebb Synapse". This is a special sort

of neural connection which responds to the coincident electrical activity of the 2 nerve

cells making the connection by becoming stronger. There are 2 important issues here:

(1) how is it that a subcellular structure can behave in this special way, as a result of the

interaction of the molecules of which it is composed.

(2) why is it that this special synaptic property can lead to "selforganisation" of extremely

complex structures, such as the human brain? – structures which seem to have minds,

even though the constituent molecules and synapses do not?

So the course both looks "down" from synapses to molecules and "up" from synapses to

minds.

The course starts out by considering 2 other examples of "looking both up and down".

Phase transitions: molecular interaction leads to unexpected properties such as the melting of ice and the magnetization of iron.

Life: Molecular selfreplication leads to even more unexpected properties: life.

 

The Lecture notes themselves are here