Douglas Heaven/New Scientist
Where does the mind reside? It’s a question that’s occupied the best brains for thousands of years. Now, a patient who is self-aware – despite lacking three regions of the brain thought to be essential for self-awareness – demonstrates that the mind remains as elusive as ever.
The finding suggests that mental functions might not be tied to fixed brain regions. Instead, the mind might be more like a virtual machine running on distributed computers, with brain resources allocated in a flexible manner, says David Rudrauf at the University of Iowa in Iowa City, who led the study of the patient.
Recent advances in functional neuroimaging – a technique that measures brain activity in the hope of finding correlations between mental functions and specific regions of the brain – have led to a wealth of studies that map particular functions onto regions.
Previous neuroimaging studies had suggested that three regions – the insular cortex, anterior cingulate cortex and medial prefrontal cortex – are critical for self-awareness. But for Rudrauf the question wasn’t settled.
So when his team heard about patient R, who had lost brain tissue including the chunks of the three ‘self-awareness’ regions following a viral infection, they immediately thought he could help set the record straight.
According to the models based on neuroimaging, says Rudrauf, “patients with no insula should be like zombies”.