von Neumann Correctly Hypothesizes How Memory Works

The question of the physical embodiment of this memory remains. For this, various authorrs have suggested a variety of solutions. It has beeen proposed to assume that the thresholds—orr, more broadly stated, the stimulation criteria—^f or various nerve cells change with time as functions of the previous history of that cell. Thus frequent use of a nerve cell might lower its threshold, i.e. ease the requirements of its stimulation, and the like. If this were true, the memory would reside i...

 The Immune System

An immune system of enormous complexity is present in all vertebrate animals. When we place a population of lymphocytes from such an animal in appropriate tissue culture fluid, and when we add an antigen, the lymphocytes will produce specific antibody molecules, in the absense of any nerve cells. I find it astonishing that the immune system embodies a degree of complexity which suggests some more or less superficial though striking analogies with human language, and that this cognitive system...

 Number of Neuron Connection in the Brain

Each nerve cell receives connections from other nerve cells at six sites called synapses. But here is an astonishing fact—there are about one million billion connections in the cortical sheet. If you were to count them, one connection (or synapse) per second, you would finish counting some thirty-two million years after you began. Another way of getting a feeling for the numbers of connections in this extraordinary structure is to consider that a large match-head's worth of your brain conta...

 The Biological Big Bang

As a scientist, I was very aware that watching a baby’s brain develop feels as if you have a front-row seat to a biological Big Bang. The brain starts out as a single cell in the womb, quiet as a secret. Within a few weeks, it is pumping out nerve cells at the astonishing rate of 8,000 per second. Within a few months, it is on its way to becoming the world’s finest thinking machine.

 An Experiment With a Tadpole's Development

An early classic experiment by the Nobel Prize-winning embryologist Roger Sperry illustrates the principle perfectly. Sperry and a colleague took a tadpole and removed a tiny square of skin from the back. They removed another square, the same size, from the belly. They then regrafted the two squares, but each in the other's place: the belly skin was grafted on the back, and the back skin on the belly. When the tadpole grew up into a frog, the result was rather pretty, as experiments in embryo...