Wiring the Brain

Why did the axon cross the midline? That seems like a simple enough biological problem to solve. In the developing nervous system, especially in the anatomically simple spinal cord, some nerve cells send a slender nerve fibre (called an axon) across the midline of the nervous system to connect to cells on the other side. The projections of other neurons are restricted to the same side as their own cell bodies. The connections between the two sides are crucial in coordinating movement of the two sides of the body. But, more importantly for this discussion, this system is simple enough to be genetically tractable – at least it seems so. When I arrived as a graduate student in the lab of Corey Goodman at the University of California at Berkeley, his group had just carried out a genetic screen in fruit flies to try and understand how this developmental decision was controlled. Flies have an equivalent of a spinal cord, called the ventral nerve cord , and Corey a...

I had an interesting exchange with philosopher Philip Goff on Twitter ( @ Philip_Goff ) recently, prompted by his article : “ Panpsychism is crazy, but it’s also most probably true”, published in Aeon. There he lays out a series of arguments that he claims make it likely that all pieces of matter possess some degree of consciousness. “ According to panpsychism, the smallest bits of matter – things such as electrons and quarks – have very basic kinds of experience; an electron has an inner life.” Image source The idea is that consciousness may be not solely a property of highly complex systems, such as ourselves, but a fundamental property of every piece of matter in the universe, like mass. Some bits of matter would have more of it than others, but all – down to the level of elementary particles like electrons and quarks – would have some kind of subjective experience. I’d like to say there’s more to it than that, that it involves a whole fleshed out framework t...