Emory University neuroscientist Gregory Berns had spent decades using imaging technology to study how the human brain works. That changed when he and his family adopted Callie, a shy, skinny terrier mix, who inspired Berns to tackle the question: ‘What is my dog thinking?’

Berns learned that military working dogs operate calmly in the most challenging environments, leading to a radical notion: Would it be possible to train dogs to hold completely still in an MRI scanner? If so, it might be possible to see how the canine brain actually works.

Berns’s colleagues dismissed the idea; everyone knew that dogs needed to be restrained or sedated for MRI scans. Berns refused to do either – instead, he painstakingly trained the dogs to sit still, even though it meant overcoming many administrative, technical, legal, and behavioural hurdles. The initial findings offer tantalising evidence on how dogs empathise with human emotions, how they love us, and why being the ‘pack leader’ with your dogs, as some experts suggest, is a mistake.