Dr Norberg used different colours to represent parts of the notoriously complex organ.
The frontal cortex is cream and pale green, the visual cortex a mix of blue, purple and turquoise while the hippocampus is made up of baby pink wool.
The two sides of the nine inch brain – one and a half times life size – are joined together by a zip with the cerebellum knitted in blue and spinal cord trailing off in white strands of wool.
Dr Norberg, from the National Bureau of Economic Research in Cambridge, Massachusetts, said she was determined to finish her challenge once she had started: “It was a labour of love.
“For me, there were two humorous aspects. One was simply to undertake such a ridiculously complex, time consuming project for no practical reason.
“The second was the idea of making a somewhat mysterious and difficult object – a brain – out of a ‘cuddly’, cheerfully coloured, familiar material like cotton yarn.”
Dr Norberg said the wool lent itself to creating the right “rippling” effect for parts of the brain and was easier to manipulate than other materials.
“The process of construction was much more similar to the actual growth of a real brain than it would have been if I’d been using a material such as clay or metal,” she said.
“You can see very naturally how the ‘rippling’ effect of the cerebral cortex emerges from properties that probably have to do with nerve cell growth.
“In the case of knitting, the effect is created by increasing the number of stitches in each row.”
Dr Norberg said she started knitting the individual parts of the brain – such as the cerebellum, brainstem and amygdala – separately before bringing them together.
Her patience paid off and the woolly brain is now on display at the Boston Museum of Science.