The Atlas of Human Brain Connections is intended to encourage reflection on two important issues in neurological sciences: the relevance of neuroanatomy to the understanding of brain function and the importance of methodological developments to the study of neuroanatomy. Aristotle, the father of comparative anatomy, was the first to tell us why it is important to study anatomy. For example, in relation to the bodies of birds he wrote ‘each bodily part is for the sake of something… Birds’ beaks… differ according to their different [ways] of life. Some beaks are… straight if they are used...
The Atlas of Human Brain Connections is intended to encourage reflection on two important issues in neurological sciences: the relevance of neuroanatomy to the understanding of brain function and the importance of methodological developments to the study of neuroanatomy. Aristotle, the father of comparative anatomy, was the first to tell us why it is important to study anatomy. For example, in relation to the bodies of birds he wrote ‘each bodily part is for the sake of something… Birds’ beaks… differ according to their different [ways] of life. Some beaks are… straight if they are used simply for feeding, curved if the bird eats raw meat, because a curved beak is useful for overpowering their prey…’ (Aristotle, 2004). Hence, ‘form and function go together for Aristotle. Anatomy and physiology are integral components of the same science’ (Blits, 1999). In teleological terms we might say that a unique form subserves a specific function; in evolutionary terms that the function shapes the form. It follows that modification of the form results in dysfunction, a corollary that applies in nature at any level. Scientists have exploited this logic to work out, in a reverse order (from functional deficits to structural modifications), the causes of human diseases. Thus, in molecular biology, the study of linear sequences of bases forming the DNA or amino acids composing proteins, and their ability to fold into relatively stable three-dimensional structures with unique transcriptional or enzymatic activities has led to important insights into normal cellular processes and pathological conditions. At a macroscopical level, the Aristotelian principle has dominated Western culture since the Renaissance (Figure 1.1). Michelangelo's obsession with the human body was driven by the hope of capturing the meaning of human existence through the representation of a perfect body. Leonardo's physiognomy attempted to reveal the many facets of ‘human passions’ through the representation of facial expressions. Both Michelangelo and Leonardo practised human body dissection, a method of scientific enquiry that grew stronger over the centuries and culminated in the work of the greatest neuroanatomists of the 18th and 19th centuries, all of whom shared a common faith in the clinico-anatomical correlation to explore disorders of the brain in both animals and humans (see Chapter 5) (Catani, 2007).
Anatomy teaching became one of the pillars of medical education. Old anatomists used to introduce their courses with the saying ‘sine anatomia non sciemus’ (‘without anatomy there is no knowledge’) and students would pay costly fees to attend extracurricular dissecting classes. With the move towards holism that took place between the two world wars and the development of more sophisticated psychological methods in the second half of the 20th century, the neuroanatomy understanding of that time became insufficient to capture the complexity of psychological functions. For many, anatomy became largely irrelevant to the development of psychological models of function and dysfunction (Catani and ffytche, 2010). This position is put in a nutshell by the American philosopher and cognitive scientist Jerry Fodor: ‘… if the mind happens in space at all, it happens somewhere north of the neck. What exactly turns on knowing how far north?’ (Fodor, 1999).
In the last decade the advent of magnetic resonance imaging (MRI) and the flourishing of techniques for structural and functional imaging are promising to reinstate anatomy to its former position. However, the importance of studying anatomy with ‘expensive’ neuroimaging techniques continues to be harshly criticized and often people wonder whether much more than a few footnotes have been added to the work of the great neuroanatomists of the past centuries. There is no doubt that neuroimaging is a very powerful tool that is contributing to our understanding of brain anatomy and function. It is also true that many findings derived from neuroimaging research are difficult to translate into benefits for patients.
In contemporary neuroscience the anatomy of the central nervous system has become essentially the anatomy of the connections between distant regions. Understanding the pattern of connectivity and how neurons communicate is probably the next frontier in neurosciences (Mesulam, 2005). Investments on a large scale for projects aimed at mapping the ‘connectome’ testify to the great interest of the scientific community in the descriptive anatomy of human brain connections. We, however, hold the view that neuroimaging has to prove its clinical validity beyond group-level analysis to stand the test of time. Unfortunately, insights from advanced imaging methods often fail to reach those clinicians who might benefit most from them. The Atlas of Human Brain Connections is intended to help neuroscientists and clinicians in the processes of correlating structure with function, and lesions with symptoms, tasks that for a long time have been within the remit of descriptive anatomy.
Chapter. 1984 words. Illustrated.
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