sense also provides a unique mechanism to test the sensory and representational theories of unilateral neglect. Olfactory information projects predominantly to the ipsilateral hemisphere. Patients with a right hemisphere lesion show left sided neglect in other modalities and fail to respond to the left contralateral nostril, thus the representational theory is supported. It was suggested that since the olfactory sensory pathways to the cerebral hemispheres were not crossed, a neglect should have occurred on the right side if a sensory loss were the cause of neglect. Neglect in olfactory sense is compared with its occurrence in the trigeminal sense, a sense stimulated in the same manner as olfaction (chemically through the nasal passages) but contralaterally innervated. Studies supporting the representational theory of unilateral neglect show that right hemisphere lesion patients with left unilateral neglect failed to respond to their left contralateral nostril on olfactory double simultaneous stimulation in spite of adequate olfactory sensitivity. This demonstrated that the occurrence of unilateral neglect is not a function of sensory attenuation, in fact, olfactory sensitivity did not correlate with number of extinctions. Extinction of taste The existence of neglect and/or extinction in taste is less explored than olfaction, even though in humans the ability to localize taste stimuli presented on the tongue has been previously described. In the case of a patient with a wide parietal-occipital tumor, tactile extinction on the upper limbs and extinction of taste sensations on the left part of the tongue were seen when two tastes were presented simultaneously on each hemitongue. The results of the assessment revealed there is unimodal taste extinction and displacement of taste sensations under crossmodal taste-tactile stimulation. In particular, when a touch was delivered to the right hemi-tongue and a taste was applied on the left hemi-tongue, the patient repeatedly reported bilateral taste stimulation, thus surprisingly extinguishing the right touch and partially misplacing the left taste stimulus. Gustatory extinction also seems to occur consequently to a severe tactile extinction. In the gustatory test done on patients with right brain damage (RHD) or left brain damage (LHD) and healthy subjects, nine RHD patients with left hemitongue tactile extinction showed no gustatory extinction for both unilateral and bilateral stimulations. Contrary to a largely crossed cortical representation of the limbs and other exteroceptive body sites, the tongue has been traditionally thought to enjoy a bilateral representation in the cortex for both somatic and gustatory modalities. In fact