Unthinkable

Author: Helen Thomson

Synopsis

This book is a fascinating exploration of some of the most extraordinary neurological disorders ever described. The author, a neuroscientist, crosses the continents to meet truly peculiar people whose brains defy the odds in every conceivable way. The author’s goal in studying these unusual people was ‘to create a picture of how the brain functions in us all…by putting their lives side by side‘ with normal brain function (page 15). In depicting the lives of these unique individuals, the book paints a picture of how they overcome the major challenges imposed on them, both by their enhanced brain capacities, and by co-existing restricted social and physical abilities.

An incredibly attractive feature of the book is how the author ingeniously blends biography and history with clinical syndrome and pathophysiology. This is brilliantly demonstrated by the story of Sharon, whose inability to create ‘an accurate mental map of her surroundings’ means she can get lost just by walking from her bathroom to her kitchen (page 49). The cause of this puzzling phenomenon, which causes the the world of the afflicted to ‘flip unexpectedly‘, is developmental topographical disorientation, first described by the psychologist Giuseppe Iaria (pages 51-64). In unravelling this condition, the author referred to several interesting neuroscience breakthroughs, for example the discovery of place cells by the neuroscientist John O’Keefe, and of grid cells by Nobel Prize winning husband and wife team, May-Britt Moser and Edvard Moser (pages 56-58).

The text is characterised, inevitably, by several references to brain structure and function, but the author very skilfully animated this potentially dry subject by linking the science with relevant clinical manifestations. This is particularly evident in her approach to disorders of memory where she referred to the hippocampus, which ‘seems to glue different aspects of memory together’, and to the amygdala, which ‘sends messages to many brain regions to increase the strength of synapses‘ (page 33). She described the retrosplenial cortex as critical for recognising familiar landmarks, and the temporoparietal junction as ‘an area that is said to help us distinguish the self from other’ (pages 56-61 and 240). The author also linked science with function when she explored cognitive maps with reference to Eleanor Maguire, the cognitive neuroscientist who demonstrated that London taxi drivers possess larger than normal posterior hippocampi (pages 55-56). 

The author was particularly interested in the human element of all the disorders she discussed. This is reflected, for example, by the fascinating case of Sylvia, whose profound synaesthesia meant she ‘had experienced a permanent hallucination every day of her life for the past decade’; and by the case of Joel, the mirror-touch synaesthete who ‘loves to see people hug‘ (pages 136 and 240). We also see this in the case of Bob, whose highly superior autobiographical memory (HSAM) is unfortunately accompanied by debilitating obsessive compulsive disorder (page 42). By exploring the human angle in this way, she arrived at many helpful conclusions, for example how to avoid burnout ‘by concentrating on compassion, rather than empathy‘ (page 247).

The book is more than just a biographical sketch of living subjects because the author complemented her case studies with key historical references. For example, she referred to the first written account of the brain, in the ancient Egyptian Edwin Smith papyrus, and to the the first dissection of the brain by the Greek anatomists Herophilus and Erasistratus (pages 2-5). She also gave the accounts of notable historical neuroscience subjects such as Henry Molaison (Patient HM), who developed severe amnesia when his hippocampi were surgically removed in an attempt to treat his intractable epilepsy; it was his unique brain that ‘provided the first fundamental evidence that specific types of memory are processed in different places’ (page 20). Another historical example, reflecting the other extreme of memory, is the enigmatic Solomon Shereshevsky, whose superior memory recall was recorded in exquisite detail by the Russian psychologist Alexander Luria (page 22).