How to breathe life back into brain theory

The brain is not a trivial object of study because how it works remains unclear despite advances in measurement and manipulation. A dominant view treats the brain like a computer, but engineering metaphors are often vague and misleading for explaining animal cognition. Real brains are not engineered, so brain science should focus on biology. Mechanistic explanations are challenged because neurons do not follow fixed rules or commands, cannot be modified arbitrarily, and do not implement computations in a straightforward way. Neural activity is not a direct code mapping one variable to another; firing rates depend on sensory details and task timing. Inferring links between brain activity and external variables does not imply the organism uses those variables as code.

"What is a brain? The question might seem obvious, but it is not trivial. Neuroscience has progressed in the past century, with the development of sophisticated techniques to measure and manipulate brain cells, neural circuits and even animal behaviours. Yet how the brain actually works still eludes us."

"He concedes that engineering metaphors can be useful but argues that they are often vague, incoherent and misleading - failing to capture animal cognition, for example. The reason is simple: real brains are not engineered. Brette aims to breathe life back into brain science by focusing the study of the nervous system on biology."

"Brains are not programmable machines, Brette contends, because neurons do not follow fixed rules or commands, cannot be modified to function arbitrarily and don't implement computations as such. Nor is neural activity a code, in which one variable is mapped directly to another (as happens in Morse code and Braille)."

"The firing rate of neurons can vary depending on the details of sensory stimuli, such as the orientation of an observed shape or the type of task being performed, and when and how it is being completed. In other words, although scientists can infer links between brain activity and external variables, this does not mean that the organism that they are studying is doing that as well."

Read at Nature