How Can We Learn From the Unwell Brain for a Healthy Mind?

Neuroscience is a young kid. Given the research boom these days, one cannot imagine that neuroscience, as a field of study, is only 100–150 years old. At the turn of the 19th to the 20th century there were no imaging/scanning devices available that could provide direct and online insight into the functioning of the brain. One source of information, however, was the clinical cases reported in neurology and psychiatry journals. The brains of patients with abnormal mental features could provide some clues about brain functioning, especially via postmortem investigation of structural abnormalities such as lesions. Despite the fact that we have fancy tools such as fMRI (functional magnetic resonance imaging) equipment these days, we nevertheless have not yet unravelled the puzzle of how the dull gray matter of the brain can generate something as colourful as the various mental features we think of as self, consciousness, emotional feelings and personal identity.

Returning to the origins of neuroscience to study the unwell brain for clues about the healthy mind brings me to the added element in the title of my forthcoming book, Neurophilosophy and the Healthy Mind: Learning from the Unwell Brain (Norton Publisher, November 2015). Over the centuries it has been philosophers who discussed and described mental features and their concepts. These particular concepts often have been carried over, into the context of neuroscience, without thorough investigation of whether such one-to-one transfer from mind to brain is really feasible and plausible. By comparing and correlating neuroscientific data and philosophical definitions of various mental concepts—for example, self, consciousness, emotional feelings, and personal identity—I reveal some major discrepancies between neuroscience and philosophy that we can overcome and bridge only by changing how we define our mental concepts in philosophy. Hence, Neurophilosophy and the Healthy Mind: Learning from the Unwell Brain carries major implications not only for how researchers in neuroscience and clinicians understand and view the brain in relation to psychiatric disorders, but also for the various kinds of puzzles often discussed by past and present philosophers.

Consider a recent study of ours by Pengmin Qin (Qin et al. 2015; Human Brain Mapping). He investigated the concentration or density of GABA-A receptors in patients with severe brain lesions who lost consciousness, e.g., vegetative state (VS). He observed that the VS patients suffered from a huge global decrease in GABA-A receptors all over the brain showing 40-50% reduction. Most importantly, he demonstrated that the degree of GABA-A receptor reduction predicted the level of consciousness three months later: the higher the degree of GABA-A receptors at the time of investigation, the more likely patients will show a higher level of consciousness three months later. GABA-A receptors are thus important for the therapeutic recovery of consciousness when it is lost as it is VS. This is the clinical side of things.

What do these results tell us about the healthy brain? They demonstrate for the first time that GABA-A receptors may be central for consciousness. Why and how? That remains unclear at this point in time. GABA-A receptors mediate inhibition or suppression of neural activity. Such gaba-ergic mediated neural inhibition seems to be important to coordinate, link and bind together the various inputs our brain receives. This hypothesis can be tested experimentally in the healthy brain. If it holds, we learned something from the unwell brain for consciousness in the healthy mind.

Human Brain Mapping. 2015 Jul 3. doi: 10.1002/hbm.22883. [Epub ahead of print]

GABAA receptor deficits predict recovery in patients with disorders of consciousness: A preliminary multimodal [11 C]Flumazenil PET and fMRI study.

Qin P1,2,3, Wu X4, Duncan NW1,2,3,5, Bao W6, Tang W7, Zhang Z6, Hu J4, Jin Y4, Wu X4, Gao L4, Lu L8, Guan Y6, Lane T2,3, Huang Z2, Bodien YG9, Giacino JT9, Mao Y4, Northoff G1,2,3,5,10.

See www.georgnorthoff.com under journal articles 2015 for the PDF

I will be back next month with another example, namely the effects of early childhood trauma on the brain’s resting state activity in adulthood which again shows how we can learn from the unwell brain in for the healthy mind.