E. G. Jones – författare

This volume deals with some of the association areas of the cerebral cortex and with the auditory cortex. In the first chapter, by Deepak Pandya and Edward Yeterian, the general architectural features and connections of cortical associ­ ation areas are considered; as these authors point out, in primates the association areas take up a considerable portion of the total cortical surface. Indeed, it is the development of the association areas that accounts for the greatest differ­ ences between the brains of primate and non primate species, and these areas have long been viewed as crucial in the formation of higher cognitive and be­ havioral functions. In the following chapter, Irving Diamond, David Fitzpatrick, and James Sprague consider the question of whether the functions of the as­ sociation areas depend on projections from the sensory areas of the cortex. They use the visual cortex to examine this question and show that there is a great deal of difference between species in the amount of dependence, the differences being paralleled by variations in the manner in which the geniculate and pulvinar nuclei of the thalamus project to the striate and extra striate cortical areas. One of the more interesting and perhaps least understood of the association areas is the cingulate cortex, discussed by Brent Vogt. Cingulate cortex has been linked with emotion and with affective responses to pain, and in his chapter Vogt gives an account of its cytoarchitecture, connections, and functions.

Volume 5 of Cerebral Cortex completes the sequence of three volumes on the individual functional areas of the cerebral cortex by covering the somatosensory and motor areas. However, the chapters on these areas lead naturally to a series of others on patterns of connectivity in the cortex, intracortical and subcortical, so that the volume as a whole achieves a much broader viewpoint. The individual chapters on the sensory-motor areas reflect the considerable diversity of interest within the field, for each of the authors has given his or her chapter a different emphasis, reflecting in part topical interest and in part the body of data resulting from work in a particular species. In considering the functional organization of the somatosensory cortex, Robert Dykes and Andre Ruest have chosen to concentrate on the nature of the mapping process and its significance. Harold Burton, in his chapter on the somatosensory fields buried in the sylvian fissure, shows how critical is an understanding of this mapping process in the functional subdivision of the cortex. A frequently overlooked subdivision of the cortex, the vestibular region, is given the emphasis it deserves in a chapter by John Fredrickson and Allan Rubin. The further functional subdivisions that occur within the first somatosensory area are given an anatom­ ical basis in the review by Edward Jones of connectivity in the primate sensory­ motor cortex.

In recent years, the suprasylvian gyrus of the cat has attracted the attention of many neurophysiologists and experimental psychologists and the variety of their interests is reflected in the number of morphological and functional sub- divisions which have been made of it. Some of these subdivisions are shown in Fig. 1. Workcrs concerned with t. hc visual system havc made studies of the third visual area (awa to) on the medial aspect. of thc gyrus, and of the latcral supra- sylvian area on the lateral aspeet, both of which contain representations of the retina (Clare and Bishop, 1954; Hubel and Wiesel, 1965, 1969; Wright, 1969). However, the full extent of these areas and particularly of the latter, is still not known. Other workers have investigated the extent of the gyrus activated by somatic sensory (Darian. Smith, Isbister, Mok and Yokota, 1966) or auditory (Woolsey, 1961) stimuli. A third field of incrcasing interest is the study of the "polysensory areas" of the cortex, two of which are situated in the middle supra- sylvian gyrus.In these areas, in animals anaesthetized with chloralose, conver- gence upon single neurons of auditory, somatic and visual impulses has been demonstrated (see ego Thompson, Johnson and Hoopes, 1963; Dubner and Rut- ledge, 1964, 1965; Dubner, 1966; Bignall, 1967) and it has been proposed that these areas play an important part in the central processing of sensory information (Buser and Bignall, 1967; Thompson, 1967).