|
|
|
May 19, 2002
SYNDICATED: Mind the gaps
THE brain is a wonderful territory for scientific exploration but there is a great deal that we don’t understand about the way it works. The bottom line of Joseph Ledoux’s Synaptic self is that we are our synapses. Synapses are the tiny gaps between nerve cells across which chemical signals pass from one nerve cell to the next. These can stimulate or inhibit the nerve cell from firing, and it is the combined influence of many inputs that determines if it does fire. But the nerve cell is just one of billions — there are a thousand million synapses in a piece of brain the size of a grain of sand — that connect in complex circuits. How these circuits behave determines how we feel, think and behave, and this is ultimately determined by what is happening at the synapses.
Ledoux describes the molecular bases of these processes in often rather technical detail, and the description of brain development is unfortunately seriously flawed. Much attention is given to the hipocampus, which plays such a key role in many brain functions, particularly memory, and the amygdala, which is at the heart of emotion. Ledoux considers the relation between what he calls the mental trilogy — cognition, emotion, motivation — and this brings into play an investigation into memory, both which is readily accessible and which is not.
He is at his best on emotion, the subject of his excellent book. The emotional brain, and his studies on fear using animal models are of particular importance. He also describes the new research that may be unlocking the molecular basis of love by studying voles — one of the few monogamous mammals. The chapter on synaptic sickness is also excellent, and the author rightly disparages the soup model phenomenon, which attributes mental illness to chemical imbalances. Instead he emphasises circuits, like those involving the amygdala, which play a key role in depression. But he fails to provide an explanation for the common and disturbing feature of depression, and somatization, which results in unpleasant physical symptoms.
Peter Hobson is a psychoanalyst, and it is to his credit that the special verbiage of his profession does not pervade the clarity of his writing in The cradle of thought. His aim is to understand the mental process of babies in order to understand how we think — including being creative and how to interact in a social setting. In order to do this he devotes much attention to the abnormalities of the mental process, thus focussing on autism. His study proves that it is the infant’s emotional engagement with other people, particularly the mother, that is the most important aspect of normal development. He dismisses the importance of the genes in controlling how the brain develops and thus functions during childhood.
The most characteristic feature of autism is the child’s inability to read other people’s minds. The classic test for this involves putting a sweet in a red box in front of John and Mary and then sending Mary out of the room. The sweet is moved to the blue box and John is asked where Mary will look for it when she returns. If John is autistic he will say Mary will look in the blue box as he cannot understand what Mary would really think. Such children have severe social behaviour difficulties.
Hobson sees the relation with the mother as fundamental and asserts that thought development is influenced by the caregiver’s emotional relationship with the infant. It is implied that the failure to properly relate is the cause of autism, and the tendency towards autism in blind children is used as support for this view. However, the evidence from those who work in this area proves that the lack of motherly care is not the sole cause for autism. Genetic factors play an important role as well; three-quarters of autism sufferers have mental retardation due to brain abnormalities.
Hobson feels that since many suffering from autism have special skills, as in the case of maths and music, their mode of thought is programmed towards local rather than social thinking. Even the cause of autism remains unknown as does the reason why boys are more autistic than girls.
While covering many aspects of the brain, both the authors miss out on some essential features. First, the only function of the brain from an evolutionary point of view is to control movement — interaction with the environment. That is why plants do not have brains. Second, what makes us different from all animals is that we have causal beliefs, and this is what enables humans to make complex tools. It is technology that has driven human evolution, not social interaction. — Dawn/Observer news service
The synaptic self
By Joseph Le Doux
Macmillan
ISBN 0333781872
406pp. £20
The cradle of thought
By Peter Hobson
Macmillan
ISBN 0333766334
307pp. £20
|
|
|
|
