Vad som avsågs, om jag nu minns rätt, var inte uppdelningen i fem smaker utan att lokaliseringen av receptorerna, som man tidigare ansett placerade i avgränsade grupper med specifik lokalisering för respektive smak, var mer "blandad". En bra sajt i ämnet:
http://www.cf.ac.uk/biosi/staff/jacob/teac...sory/taste.html där man kan läsa:
"Regional localisation of taste on the tongue (Taste maps)
There has been some controversy as to whether the familiar taste maps of the human tongue, which appear in every textbook, are correct. Taste sensation can be localised on the tongue but does the tongue have regions that are more sensitive to one taste modality than another? Fungiform papillae are concentrated on the anterior tip of the tongue and anterior lateral margins in humans and it has been demonstrated that NaCl threshold was inversely related to the number of fungiform papillae (more papillae = more sensitivity, lower threshold). In a study of human fungiform papillae it was found that taste buds can respond to NaCl only or to both NaCl and sucrose. The responses to NaCl and sucrose occurred in different cells within the taste bud. Thus, one can infer that fungiform papillae are salt-sensitive but this does not mean they are insensitive to other tastes. Bitter receptors are not uniformly distributed over the tongue. In rats the bitter receptors are expressed in a subset of taste cells in all papillae but they are more concentrated in foliate and circumvallate papillae situated at the sides and the back of the tongue. Furthermore, alpha-gustducin, which is the G-protein coupled to the T2R bitter receptors (see below), is expressed more in circumvallate than fungiform papillae in the rat. One rather more empirical approach to resolving this question is to stimulate the different areas of the tongue directly. Thermal stimulation of the anterior sides of the tongue in humans (fungiform papillae and the chorda tympani nerve) evokes sweet and salt/sour taste. While thermal stimulation of the rear of the tongue (foliate/circumvallate papillae and glossopharyngeal nerve) causes a different relationship between temperature and taste to the anterior stimulation. One can conclude that the classical "taste map" is an over simplification. Sensitivity to all tastes is distributed across the whole tongue and indeed to other regions of the mouth where there are taste buds (epiglottis, soft palate), but some areas are indeed more responsive to certain tastes than others."
På svenska finns:
http://www.biol.lu.se/zoofysiol/Svar/Lukt.html