THE HUMAN BRAIN is a truly astonishing product of evolutionary development. Contained within its one-and-a-half kilograms of organic matter are all of our sensations, perceptions, interpretations, emotions, memories and our sense of ourselves as sentient beings.
Most of the time the neurological processes of normal brain function carry on meticulously and unnoticed as we conduct our lives. However, from time to time this precise biological routine is disrupted by disease or trauma. The consequences of such events, while often distressing, can provide important insights into how the brain works.
Perhaps the most famous case of trauma induced brain damage is that of Phineas Gage, an American railroad construction foreman who was injured while packing down a blasting powder charge into a rock face. The powder exploded and a three-and-a-half-foot long metal bar was propelled through his left eye and out through the top of his head. The iron bar landed about eighty feet away.
Remarkably, Gage recovered physically from this horrendous experience but is reported to have undergone significant personality change as a consequence of extensive frontal lobe damage. Because of this he did not return to his position as foreman and worked in a variety of other jobs until his death in 1860, twelve years after the accident.
In a recently published book entitled The Tell-Tale Brain: Unlocking the mystery of human nature VS Ramachandranexamines a range of rare and unusual delusional syndromes in an attempt to shed light on such complex areas as self-awareness, free will and consciousness. While not clearly answering such vexing conundrums, this book and his other writings do provide a fascinating insight into strange worlds that emerge as a consequence of neurological damage.
One condition referred to is akinetic mutism in which a patient lies in bed, fully conscious and alert, but unable to talk or move around. When recovered the patient describes the condition as a loss of will to respond.
An intriguing adjunct to this condition is referred to as “telephone syndrome”. It may happen for example that the patient shows no response to his father when he is in the room, but if his father goes next door and speaks with him on the telephone he becomes immediately animated and engages in a perfectly normal fashion. This condition arises from damage to an area of the brain called the anterior cingulate. This area is thought to be involved in attention, vigilance and free will.
Capgras delusion is a rare condition in which an individual comes to believe that a close relative, his mother for example, has been replaced by an exact lookalike. The patient recognises his mother, but experiences none of the emotional responses that would normally accompany meeting her. Therefore he concludes that his mother has been replaced by an impostor.
It has been postulated that in the case of the Capgras delusion, the link between the right temporal lobe of the brain where perception emerges into conscious awareness and the amygdala, the emotional centre of the brain, has been damaged.
Cotard delusion is one in which the patient claims that he or she is dead. This is thought to be an exaggerated form of Capgras delusion in which a wide variety of sensory areas are divorced from the emotional centres of the brain and the entire world – including the patient himself – becomes an impostor and he feels alienated or dead.
Ramachandran also refers to phantom limb pain. A person who has undergone an amputation of an arm, for example, may experience a phantom limb in which the hand is permanently clenched, resulting in excruciatingly painful spasm.
In an attempt to alleviate the pain Ramachandran built a box containing a mirror which allowed a reflection of the remaining hand to appear as the missing hand. Instructing the patient to open and close her hand and to wiggle her fingers on both sides as she observed what appeared to be the missing hand resulted in a sensation of movement in the phantom limb and a relief from pain which was made permanent with practice.
While many of the above conditions and phenomena are far from fully understood it is clear that the experiences described are a consequence of disturbed brain processes. According to Ramachandran, studying such conditions in more detail will help expand our understanding of brain function, self awareness and ultimately, consciousness itself.
Paul O’Donoghue is a clinical psychologist and founder member of the Irish Skeptics Society