You could double the number of synaptic connections in a very simple neurocircuit as a result of experience and learning. The reason for that was that long-term memory alters the expression of genes in nerve cells, which is the cause of the growth of new synaptic connections.
The brain has this amazing level of almost fractal complexity to it. When you start looking at any part of it in detail, you realize that it's much more complex than you thought.
Because many squid have brain nerve fibres that are hundreds of times thicker than those of humans, neuroscientists have long used them for research. These nerve fibres have led to so many breakthroughs in the study of neurons that many scientists joke that the squid should receive a Nobel Prize.
Studies by many labs have already started to identify specific circuits of neurons involved in normal cognitive function like memory and learning, as well as disease processes such as Parkinson's disease, depression, and autism.
As the brain matures, one thing that happens is the pruning of the synapses. Synaptic pruning does not occur willy-nilly; it depends largely on how any one brain pathway is used.
I think that we are already making steps toward mapping out the brain so we can identify the chemical patterns that create and store memory.
The circadian neurons are one of the few circuits in neurobiology where we have a chance to understand at multiple levels how different sets of neurons communicate with each other - including understanding the wiring rules, the biochemical rules, and the functional behavioral rules.
There is no real independent self, aloof from other human beings, inspecting the world, inspecting other people. You are, in fact, connected not just via Facebook and Internet, you're actually quite literally connected by your neurons.
It is now widely realized that nearly all the 'classical' problems of molecular biology have either been solved or will be solved in the next decade. The entry of large numbers of American and other biochemists into the field will ensure that all the chemical details of replication and transcription will be elucidated. Because of this, I have long felt that the future of molecular biology lies in the extension of research to other fields of biology, notably development and the nervous system.
Most theoretical work since the proposals of Hebb (1949) and Hayek (1952) has relied upon particular forms of dependent synaptic rules in which either pre- or postsynaptic change is contingent upon closely occurring events in both neurons taking part in the synapse.
In the early Sixties, having begun to describe the physiology of cells in the adult cat visual cortex, David Hubel and I decided to investigate how the highly specific response properties of cortical cells emerged during postnatal development.
Your brain is built of cells called neurons and glia - hundreds of billions of them. Each one of these cells is as complicated as a city.
Unlike the heart or kidney, which have a small, defined set of cell types, we still do not have a taxonomy of neurons, and neuroscientists still argue whether specific types of neurons are unique to humans. But there is no disputing that neurons are only about 10 percent of the cells in the human brain.
I would argue that if you understand how the cells of the brain are organized into circuits, almost computational circuits if you will, and we see how information flows through those circuits and how it's transformed, we might have a much firmer grasp on why our brains make decisions the way that they do. If we get a handle on that, maybe we can overcome some of our limitations and at the very least we'll understand why we do what we do.
We now know, from the latest research about neurons, that we are hard-wired for empathy. We're hard-wired for cooperation. That is something about what we are as people - what it means to be a human being. And what Barack Obama was addressing was not just race or just the nature of politics. The great speeches address who we are as people, what it means to be a human being.
