Synaesthesia is a condition in which a mixing of the senses occurs; for example, sounds trigger the experience of colour. Previous reports suggest this may be familial, but no systematic studies exist. In addition, there are no reliable prevalence or sex-ratio figures for the condition, which is essential for establishing if the reported sex ratio (female bias) is reliable, and if this implicates a sex-linked genetic mechanism. Two independent population studies were conducted in the city of Cambridge, England (studies 1 and 2 here), as necessary background to the family genetic study of synaesthesia (study 3). Studies 1 and 2 arrived at an almost identical prevalence rate for synaesthesia: approximately 1 case in 2000. The sex ratio found was 6:1 (female:male). A third of cases also reported familial aggregation. In study 3 six families were examined, and first-degree relatives were tested for genuineness of the condition. All six families were indeed multiplex for synaesthesia. Alternative modes of inheritance are discussed.

Evidence was reported earlier from a single case that chromatic-lexical (CL) synaesthesia was a genuine phenomenon. A study is presented in which nine subjects were tested who also reported having coloured hearing. The following questions were addressed: (a) were these cases also genuine (ie consistent over time), (b) were they truly lexical, or rather variants of this condition, such as chromatic-graphemic (CG) or chromatic-phonemic (CP) synaesthesia, (c) did the experimental subjects show any commonalities between them, and (d) were they able to give information on a standard questionnaire about the phenomenology and ontogenesis of the condition? Subjects were asked to describe the colour sensation experienced on hearing items from a list of 130 words, phrases, and letters. The experimental group were not informed of any retest, but were retested more than one year later. A control group (n = 9), matched for IQ, memory, age, and gender, were read the same list and asked to associate a colour with each list item. They were informed at the time of testing that they would be retested on a sample of items from the list a week later. 92.3% of the responses of the experimental group when retested one year later were identical to those given in the original test, compared with only 37.6% of the control subjects' responses (retested one week later). This confirmed the genuinneess of these nine cases. All nine experimental subjects showed CG synaesthesia, none showing either CL or CP synaesthesia. Among the experimental group, some consistency was found in the colours evoked by hearing specific letters, suggesting the condition has a neurological basis.(ABSTRACT TRUNCATED AT 250 WORDS)

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The organophosphorus nerve agents sarin, soman, cyclosarin and tabun phosphylate a tyrosine residue on albumin in human blood. These adducts may offer relatively long-lived biological markers of nerve agent exposure that do not 'age' rapidly, and which are not degraded by therapy with oximes. Sensitive methods for the detection of these adducts have been developed using liquid chromatography-tandem mass spectrometry. Adducts of all four nerve agents were detected in the blood of exposed guinea pigs being used in studies to improve medical countermeasures. The tyrosine adducts with soman and tabun were detected in guinea pigs receiving therapy 7 days following subcutaneous administration of five times the LD(50) dose of the respective nerve agent. VX also forms a tyrosine adduct in human blood in vitro but only at high concentrations.

We have defined areas in the brain activated during speaking, utilizing positron emission tomography. Six normal subjects continuously repeated the phrase "Buy Bobby a poppy" (requiring minimal language processing) in four ways: A) spoken aloud, B) mouthed silently, C) without articulation, and D) thought silently. Statistical comparison of images from conditions A with C and B with D highlighted areas associated with articulation alone, because control of breathing for speech was controlled for; we found bilateral activations in sensorimotor cortex and cerebellum with right-sided activation in the thalamus/caudate nucleus. Contrasting images from conditions A with B and C with D highlighted areas associated with the control of breathing for speech, vocalization, and hearing, because articulation was controlled for; we found bilateral activations in sensorimotor and motor cortex, close to but distinct from the activations in the preceding contrast, together with activations in thalamus, cerebellum, and supplementary motor area. In neither subtraction was there activation in Broca's area. These results emphasize the bilaterality of the cerebral control of "speaking" without language processing.