The last 10 years of the 20th century have been designated the decade of the brain. But, with the notable exception of the revolution in brain imaging, the explosion of activity in neurobiology has failed to capture the imagination of most doctors. To remedy this, we asked six neuroscientists to write about what interested them most.
If you thought that visual processing was restricted to the striate cortex of the occipital lobes, turn to Adam Zeman’s article (p 1696). More than 30 separate cortical representations of the visual field have now been identified, and positron emission tomography is revealing what each contributes to the analysis of complex visual stimuli. Richard Gregory also discusses vision, though from a different point of view (p 1693). He asks (and suggests an answer) why real time sensory inputs should be associated with conscious perception.
Consciousness, however one defines it, seems to be a property of the brain as a functioning system—not something that resides in individual neurones. Almost the opposite seems to be true of the way the brain keeps track of time. The central circadian clock is localised in the suprachiasmatic nucleus of the hypothalamus, but, as Michael Hastings explains, single nerve cells from this area retain the capacity to show a 24 hour rhythm even when isolated in culture (p 1704).
Ian Deary and Susan Greenfield tackle issues of more immediate clinical relevance. Deary discusses the validity of attempts to measure cognitive ability (p 1701), while Greenfield explores how recent discoveries about central neurotransmitters could be exploited for treating neurodegenerative disease (p 1698).
Understanding how the brain works requires more than knowledge of the intricacies of neuronal connections and neurotransmitters. In the last article Steven Rose points out the limitations of our current reductionist concepts (p 1707). He is especially scathing about the tendency to attribute complicated patterns of human behaviour—homosexuality or aggression, for example—to genetic polymorphisms. Along with A M Daniels’ cow slaughtering piece (p 1728), it provides a salutary warning against triumphalist neuroscientific hype.
Clinical review pp 1696-708