Like and cross modality responses in normal and subnormal children

Experiments which investigated response behaviour in imbeciles and normals, in a conflict situation between a general verbal instruction and direct stimuli, were carried out. It was found that combined verbal-motor responses did not give better results than either verbal or motor responses alone. Results in accordance with the general instruction were significantly better if the subnormal children responded in a different modality from the one in which the signals were given. While normals and imbeciles differed markedly in their ability to perform the tasks in like-modality trials, this difference was less apparent in cross modality responses.

The Comparative Judgements of Generally and Specifically Gifted Children

Different groups of children were compared on sentence verification tasks. The children were either academically, musically or artistically gifted, and there were two forms of the task. In one, a picture was followed by a sentence, and in another, one sentence was followed by another. Subjects had to decide as quickly as possible whether or not the second proposition logically confirmed the first. In the picture-sentence condition results from all groups could be fitted to the constituent comparison model for sentence verification proposed by Carpenter and Just (1975). For the sentence-sentence condition, however, the observed results diverged from those predicted by the model. The results are explained in terms of different degrees of linguistic processing capacities of the subjects, and they demonstrate the importance which verbal-logical congruence has for children. Artistically able children had difficulties in processing subject/object incongruence in sentence pairs whereas musically able children had more problems in processing above/below incongruence.

Shorter Articles and Notes: Like and Cross Modality Recognition in Subnormal Children

The ability of mentally subnormal children to recognize previously presented visual or verbal stimuli was compared. In “like-modality” procedures they had to recognize words or pictures in the modality in which they had originally been presented. In “cross-modality” procedures the stimulus they had to recognize was in the opposite modality from that which had been used for the first presentation.

In every recognition test the items had to be recognized from among an equal number of novel stimuli. Cross-modality procedures resulted in higher recognition scores. The hypothesis is advanced that this could be accounted for by the necessary translation from one type of sensory image to another in the cross-modality trials, which might minimize over-generalization.

MDR3 gene defect in adults with symptomatic intrahepatic and gallbladder cholesterol cholelithiasis

BACKGROUND & AIMS

Many studies indicate that gallstone susceptibility has genetic components. MDR3 is the phosphatidylcholine translocator across the hepatocyte canalicular membrane. Because phospholipids are a carrier and a solvent of cholesterol in hepatic bile, we hypothesized that a defect in the MDR3 gene could be the genetic basis for peculiar forms of cholesterol gallstone disease, in particular those associated with symptoms and cholestasis without evident common bile duct stone.

METHODS

We studied 6 adult patients with a peculiar form of cholelithiasis. MDR3 gene sequence was determined by reverse-transcription polymerase chain reaction amplification of mononuclear cell RNAs followed by direct sequencing. Hepatic bile was analyzed in 2 patients.

RESULTS

All patients shared the following features: at least 1 episode of biliary colic, pancreatitis, or cholangitis; biochemical evidence of chronic cholestasis; recurrence of symptoms after cholecystectomy; presence of echogenic material in the intrahepatic bile ducts; and prevention of recurrence by ursodeoxycholic acid therapy. Hepatic bile composition showed a high cholesterol/phospholipid ratio and cholesterol crystals. In all patients, we found MDR3 gene mutations involving a conserved amino acid region.

CONCLUSIONS

These preliminary observations suggest that MDR3 gene mutations represent a genetic factor involved in this peculiar form of cholesterol gallstone disease in adults. They require further studies to assess the prevalence of MDR3 gene defects in symptomatic and silent cholesterol gallstone disease.

Differential HFE allele expression in hemochromatosis heterozygotes

BACKGROUND & AIMS

Hereditary hemochromatosis is associated with C282Y homozygosity. Some heterozygotes may also present with abnormal iron parameters. However, the precise role of H63D and C282Y mutations in iron overload is poorly understood. We investigated the level of expression of the mutated and unmutated HFE alleles in these heterozygous patients.

METHODS

We studied the expression of HFE messenger RNAs in peripheral blood mononuclear cells from 34 heterozygotes using reverse-transcription polymerase chain reaction (PCR) followed by enzymatic digestion or sequence analysis of the PCR products, which allows relative quantification of mutated and unmutated transcripts. HFE proteins were quantified by Western blotting in Epstein-Barr virus-immortalized lymphocyte extracts from 2 C282Y and H63D homozygotes and a compound heterozygote.

RESULTS

(187C > G; H63D) mutated transcripts predominated in H63D and compound heterozygotes and the normal transcripts in C282Y heterozygotes. The amount of HFE protein was increased in the H63D homozygotes and the compound heterozygote compared with the C282Y homozygotes. In addition, we found a new mutation at codon 282 (C282S) associated with severe iron overload.

CONCLUSIONS

We demonstrate the existence of differential allelic expression of the HFE alleles, suggesting that the (187C > G; H63D) mutation plays a role in the disease expression in H63D heterozygotes, in particular when associated with environmental or host factors.

Can children with autistic spectrum disorders perceive affect in music? An experimental investigation

BACKGROUND

Children with autistic spectrum disorders typically show impairments in processing affective information within social and interpersonal domains. It has yet to be established whether such difficulties persist in the area of music; a domain which is characteristically rich in emotional content.

METHODS

Fourteen children with autism and Asperger syndrome and their age and intelligence matched controls were tested for their ability to identify the affective connotations of melodies in the major or minor musical mode. They were required to match musical fragments with schematic representations of happy and sad faces.

RESULTS

The groups did not differ in their ability to ascribe the musical examples to the two affective categories.

CONCLUSIONS

In contrast to their performance within social and interpersonal domains, children with autistic disorders showed no deficits in processing affect in musical stimuli.

A visually impaired savant artist: interacting perceptual and memory representations

In this single case study, paintings by a visually impaired and cognitively handicapped savant artist are evaluated. He paints his pictures exclusively from memory, either after having looked at a natural scene through binoculars, or after studying landscape photographs in brochures, catalogues, and books. The paintings are compared with the models from which they were derived, and the resulting generative changes are accounted for by an interaction between impaired visual input and memory transformations.

A date to remember: the nature of memory in savant calendrical calculators

BACKGROUND

Savant calendar calculators can supply with speed the day of the week of a given date. Although memory is suggested to be an important component of this unusual ability, memory function has never been systematically investigated in these skilled yet learning impaired individuals.

METHODS

Eight savant calendrical calculators, most of whom had autism, were compared with eight verbal IQ, age and diagnosis matched controls on digit and word span tests and measures of long-term memory for words and calendrical information (individual years). In an analogue to the 'generation effect', the savants' memory for dates was also compared following calculation and study/read tasks.

RESULTS

The savants did not differ from controls on measures of general short- and long-term memory. They did, however, show a clear recall superiority for the long-term retention of calendrical material. They also remembered calculated dates better than those that were only studied.

CONCLUSIONS

A general mnemonic advantage cannot explain savant date calculation skills. Rather, through exposure to date information, the savants are suggested to develop a structured calendar-related knowledge base with the process of calculation utilizing the interrelations within this knowledge store. The cognitive processing style characteristic of autism may also play a role in the acquisition of this savant ability.

The pictorial context dependency of savant artists: a research note

The relative immunity of the concept of size constancy in the face of changes to the retinal image as well as the pictorial device of linear perspective were investigated with 9 savant artists and 9 controls. For drawing use of pictorial rules seemed independent of levels of intelligence; however, when a construction instead of a drawing task had to be carried out, diagnosis rather than the presence or absence of talent was the decisive factor.

Enterocyte differentiation is compatible with SV40 large T expression and loss of p53 function in human colonic Caco-2 cells. Status of the pRb1 and pRb2 tumor suppressor gene products

Transfer of the SV40 large-T (LT) oncogene into isolated human and murine intestinal epithelial cells induced alterations of the ultrastructural organization and polarization of the resulting immortalized cell lines. We now demonstrate that the functional expression of the SV40 LT antigen in Caco-2 cells did not alter phenotypic markers of differentiation, including expression of villin, sucrase-isomaltase, brush border and dome formation. As compared to parental cells, the transfected Caco-2 LT9 cells exhibited similar growth curves and no invasive properties in vitro. The major oncogenic function of the SV40 LT antigen in transfected Caco-2 cells is associated with reduced latency times necessary for the manifestation of tumors in athymic nude mice. The Caco-2 cell line contained deleted and mutant p53 alleles (stop codon in position 204) and has no detectable truncated p53 protein by Western blot. Molecular complexes between the SV40 LT antigen and the retinoblastoma-related proteins pRb1 and Rb2 were clearly identified at the different phases of the growth curve. When compared to normal human colonic crypts, Caco-2 cell differentiation is related to partial redistribution of pRb1 into hypophosphorylated, antiproliferative forms. The pRb2 protein is found elevated in a subset of human colorectal tumors and their corresponding liver metastases. We conclude that: (1) Caco-2 cells exert a dominant control against the oncogenic functions of the LT antigen; (2) loss of p53 function is not restrictive for the establishment of polarity and differentiation of the enterocyte lineage; (3) the levels and phosphorylation status of the Rb1 and Rb2 proteins may play important roles in the proliferation and differentiation of normal and neoplastic human colonic mucosa.

Overexpression of p53 mRNA in colorectal cancer and its relationship to p53 gene mutation

We analysed the frequency of p53 mRNA overexpression in a series of 109 primary colorectal carcinomas and its association with p53 gene mutation, which has been correlated with short survival. Sixty-nine of the 109 cases (63%) demonstrated p53 mRNA overexpression, without any correlation with stage or site of disease. Comparison with p53 gene mutation indicated that, besides cases in which p53 gene mutation and p53 mRNA overexpression were either both present (40 cases) or both absent (36 cases), there were also cases in which p53 mRNA was overexpressed in the absence of any mutation (29 cases) and those with a mutant gene in which the mRNA was not overexpressed (four cases). Moreover, the mutant p53 tumours exhibited an increase of p53 mRNA expression, which was significantly higher in tumours expressing the mutated allele alone than in tumours expressing both wild- and mutated-type alleles. These data (1) show that p53 mRNA overexpression is a frequent event in colorectal tumours and is not predictive of the status of the gene, i.e. whether or not a mutation is present; (2) provide further evidence that p53 protein overexpression does not only result from an increase in the half-life of mutated p53 and suggest that inactivation of the p53 function in colorectal cancers involves at least two distinct mechanisms, including p53 overexpression and/or mutation; and (3) suggest that p53 mRNA overexpression is an early event, since it is not correlated with Dukes stage.

A savant poet

Poems by an individual with a diagnosis of Asperger's Syndrome were analysed and compared with those of a comparison poet. Though the savant poet performed less efficiently on formal language tests supposed to tap creativity, there were few differences between the two poets in regard to the poems' content and the use of various structural devices. The poems by the savant referred more often to aspects of self-analysis, while descriptions of people not related to the self were less frequent. Both poets made use of similes and metaphors. The results are discussed in terms of different modular domains within the language system.

Phenotypic expression in double heterozygotes for familial hypercholesterolemia and familial defective apolipoprotein B-100

Variability in the expression of monogenic lipid disorders may be observed in patients carrying the same DNA mutation, suggesting possible genetic or environmental interactions. Our objective was to investigate the genotype-phenotype relationships in two unrelated French patients with an aggravated expression of a dominantly inherited hypercholesterolemia. In probands, segregation analysis complemented by DNA sequencing identified heterozygous defective alleles and mutations on two nonallelic loci for two monogenic lipid disorders: familial hypercholesterolemia at the low density lipoprotein (LDL) receptor locus and familial defective apolipoprotein B-100 at the locus encoding its ligand, apolipoprotein B-100. The LDL-receptor missense mutations had been reported in French Canadians. The apolipoprotein B mutation was the Arg3500Gln founder mutation in Northern Europe. Probands had an unusual phenotype of aggravated hypercholesterolemia that was complicated with premature coronary arterial disease, although remaining responsive to lipid-lowering drugs. This phenotype was distinct from that observed in their heterozygous relatives and distinct from those observed in FH or FDB homozygotes. These cases refer to a new class of patients with digenic lipid disorders, defined by specific clinical features that result from the combined effects of two independent loci. Moreover, the observed phenotype of aggravated hypercholesterolemia gives further evidence that receptor and ligand play distinct roles in regulating LDL metabolism. Although uncommon, these cases give insight into the molecular mechanisms that underly the clinical variability of inherited hypercholesterolemia.

Recurrent and novel LDL receptor gene mutations causing heterozygous familial hypercholesterolemia in La Habana

The molecular basis of familial hypercholesterolemia (FH) in three families of Spanish descent from La Habana was investigated by the candidate gene approach. The Arg3500Gln mutation of apolipoprotein B-100 was not found. Identification of low density lipoprotein receptor (LDLR) gene haplotypes segregating with FH guided the characterisation of three point mutations by automated sequencing. One, a Val408-->Met missense mutation, a founder mutation in Afrikaner FH patients, was recurrent, being associated with a distinct DNA haplotype. The other two, Glu256-->Lys and Val776-->Met missense mutations, were novel and modified highly conserved residues. These mutations were absent in normolipidemic subjects and were associated in heterozygous carriers with twice the cholesterol levels observed in non-carriers. Noticeably, cardiovascular complications were rarely observed in older heterozygotes, even in those with the Afrikaner FH-2 mutation. These findings confirm the molecular heterogeneity of LDLR gene mutations causing FH and the variability of their expression across different populations.

Savants, segments, art and autism

This study describes two experiments which investigate pattern construction by graphically gifted, autistic savants. We explore whether the notion of weak central coherence in autism might be extended to account for the relatively high frequency of savants among the autistic population. We also suggest that an awareness of constituent segments in wholes may be relevant to artistic talent in general.

Preliminary results of Pneumocystis carinii strain differentiation by using molecular biology

The mode of Pneumocystis carinii transmission is controversial. Recent studies point to exogenous inoculation rather than reactivation, and person-to-person transmission has also been suggested. Comparison of nucleotide sequences of the large-subunit mitochondrial rRNA gene of P. carinii from human immunodeficiency virus-seropositive patients showed strain differences.

Visual and motor functions in graphically gifted savants

Savant artists represent a conundrum to our understanding of the nature of high level specific talents as well as to the concept of general intellectual impairment. In the present paper, we are particularly concerned with the relationship between general perceptual-motor functions in relation to drawing aptitude. Drawing is by definition a perceptual-motor operation, yet mental handicap tends to be associated with some degree of impairment in this area. The following study seeks to isolate such aspects of performance on general perceptual-motor skills that might be associated with drawing ability, and may thus be regarded as building blocks underlying the manifestation of graphic talent. The results are discussed in terms of the relationships between graphic talent, non-verbal intelligence and visual-motor functions.

Two autistic savant readers

Two young autistic children of normal intelligence were tested repeatedly for their reading ability. Their comprehension was appropriate for their developmental status, however, they had reading speeds that were considerably faster than those of their age-matched normal controls. Randomizing word order, and thereby reducing meaningfulness, resulted in an equivalent reduction in relative reading speeds for the younger autistic subject and his control. For the older of the normal children, the effect of randomizing word order was very marked, whereas its effect was minimal for the older of the two autistic boys. The results are regarded as an indication that efficient grapheme-phoneme conversion is a modular component of the reading skill and this transcoding process is primarily responsible for the fast reading of the autistic children.

Phosphorylation of vimentin is an intermediate step in protein kinase C-mediated glycoconjugate secretion

We have previously shown that fibroblasts from patients with cystic fibrosis (CF) display a higher response to 4 beta-phorbol 12-myristate 13-acetate (PMA) than control fibroblasts for stimulation of both protein kinase C (PKC) cytosol-to-membrane translocation and glycoconjugate secretion. In this study we took advantage of these cells with differential responsiveness to PMA to investigate the endogenous substrate(s) involved in PKC stimulation of glycoconjugate secretion after verification of cystic fibrosis transmembrane conductance regulator gene expression in control and CF fibroblasts. We show that a 57-kDa protein that was associated with cytoskeleton and was identified as vimentin by immunoblotting emerged as a good candidate for mediating PKC stimulation of glycoconjugate secretion. 1) Its phosphorylation by PMA was abolished by PKC inhibition or depletion. 2) In both control and CF fibroblasts, the PMA-induced increase in its phosphorylation preceded the phorbol ester stimulation of glycoconjugate secretion. 3) For both processes, the concentration-response curves were superimposable, with higher maximal levels for CF fibroblasts relative to controls. 4) PMA-stimulated 57-kDa protein phosphorylation, like PMA-stimulated glycoconjugate secretion, was significantly increased by Ca2+. 5) Increased PMA phosphorylation of the 57-kDa protein as a result of okadaic acid inhibition of intracellular phosphatases was reflected in increased PMA stimulation of glycoconjugate secretion. In conclusion, 1) PMA phosphorylation of a cytoskeletal 57-kDa protein, identified as vimentin, appears to be an intermediate step in PKC stimulation of constitutive glycoconjugate secretion in human skin fibroblasts; and 2) this process is impaired in CF disease.

Bottle, tulip and wineglass: semantic and structural picture processing by savant artists

Semantic and structural aspects of picture processing were investigated with graphically gifted mentally handicapped subjects and intellectually normal children. The results suggest that savants as well as controls rely primarily on semantically organised memory schemata when reproducing pictures. A semantically determined strategy also determines picture sorting. The findings indicate that within the domain of expertise there appears to be no difference between savants and normals regarding the nature of the mental structures underlying specific talents. The mental structures on which such talents are based, should therefore be regarded as being relatively independent of the level of general cognitive functioning.

Do young calendrical calculators improve with age?

The calendrical calculation performance of two 10-year-old children of the same intelligence level (IQ 90) but different calendrical ability, was compared with the performance of eight adult idiot-savant calculators. The calculating speeds of the two 10-year olds fell within the range of the reaction times of the adult savants. No improvement was detectable in a series of successive trials over time, either in speed or accuracy. It is concluded that the young calculators have already inferred rules about calendrical structure and that their performance cannot be accounted for by practice alone, but these savants use cognitive strategies to aid their performance.

Talents and preoccupations in idiots-savants

The question was asked whether a diagnosis of autism or a tendency to repetitive behaviour and preoccupation with a restricted area of interest, were crucial features of idiot-savant talents. Answers by caretakers to a questionnaire on these topics revealed that autistic and nonautistic savants resembled each other closely in preoccupation but differed from controls matched for IQ and diagnosis. In addition, the mentally handicapped showed fewer repetitive tendencies than did autistic controls. It is concluded that independent of diagnosis, preoccupations and repetitive behaviour appear to be closely associated with the manifestation of idiot-savant talents.

Regulation of secretion in cultured tracheal serous cells by protein kinases A and C

We recently reported that cultured gland serous cells release chondroitin sulfate proteoglycans (CSPGs) in response to beta-adrenergic agonists. In this study, we analyzed this regulatory pathway and other cellular mechanisms responsible for CSPG secretion. We show the following. 1) Isoproterenol increased CSPG secretion in a concentration-dependent manner, with maximal stimulation (50%) obtained at 10(-5) M; at this concentration, the beta-agonist also stimulated protein kinase A (PKA) by 50%, whereas it increased cellular adenosine 3',5'-cyclic monophosphate (cAMP) content by 300%. 2) Phenylephrine (10(-5) M), 4 beta-phorbol 12 beta-myristate 13 alpha-acetate (1.6 x 10(-7) M), and A23187 (10(-6) M) also stimulated CSPG secretion; this stimulation was concomitant with protein kinase C (PKC) translocation from cytosol to membrane, was blocked by sphingosine (2 x 10(-5) M), and was additive with that elicited by isoproterenol. 3) All PKC activators potentiated the isoproterenol-induced increased in cAMP accumulation without modifying the activation of PKA elicited by the beta-agonist. Our results indicate that although the signaling pathways triggered by alpha- and beta-adrenergic agonists converge at the level of adenylate cyclase in tracheal serous cells, PKA and PKC independently regulate CSPG secretion.

A specific linguistic ability

A young man with diagnosed hydrocephalic brain injury was found to be an able linguist. His ability to translate into English from French, German, and Spanish was confirmed to be at a high level, and his capacity to express thoughts and describe scenes in these languages was also verified. A set of translations of the Peabody Picture Vocabulary Test was prepared in French, German, and Spanish, and IQs were derived in each language. The subject's performance intelligence was tested separately and found to be low, especially in relation to spatial reasoning. The subject's linguistic achievements were discussed in terms of an IQ-independent linguistic talent.

Pericellular glycoconjugates of cultured fibroblasts from control and cystic fibrosis patients

1. Labeled glycoconjugates released by trypsin from cell surfaces of control and cystic fibrosis (CF) skin fibroblasts were purified and fractionated by column chromatography on Sephadex G-50 and Concanavalin A Sepharose. Based on chemical analysis and specific enzymatic digestions: (1) Glycoconjugates were characterized as O-linked glycopeptides consisting predominantly of glycosaminoglycan type and N-linked glycopeptides with glycans of complex type. Their relative proportions were similar between the two groups. (2) The N-linked glycopeptides exhibited an increased molar ratio of fucose to galactose in CF fibroblasts. (3) When pericellular glycoconjugates were metabolically labeled with [14C]glucosamine and [3H]fucose, incorporation and degradation kinetics were similar between the two groups.

Further evidence for abnormal protein kinase C regulation of macromolecule secretion in fibroblasts from cystic fibrosis patients

In comparison to skin fibroblasts from normal subjects, those from patients with cystic fibrosis (CF): (1) bound [20-3H] phorbol 12,13-dibutyrate (PDBu) with a higher affinity Kd = 25.8 vs 12.8 nM respectively) but expressed a similar number of total phorbol ester binding sites (about 2.5 pmol PDBu bound/mg of protein); (2) exhibited a faster and higher response to 4 beta-phorbol 12 beta-myristate 13 alpha-acetate (PMA) for the stimulation of [35S]-labelled glycoconjugate release, but were equally sensitive to the synergistic effect of A23187 on this process; and (3) secreted glycoconjugates with similar [35S]-sulfate and [14C]-leucine to [14C]-glucosamine labelling ratios. Taken together, these results provide further evidence for abnormal protein kinase C (PKC) regulation of macromolecule secretion in CF disease.

Factors and primes: a specific numerical ability

An autistic young man and a normal control were asked to factorize numbers and to recognize and generate primes. Both subjects made a similar number of errors and employed similar strategies, but they differed markedly in the speeds at which the arithmetical operations were carried out.

The recognition failure and graphic success of idiot-savant artists

Three groups of subjects, an idiot-savant group, a group of mentally handicapped subjects matched for IQ, and normal artistically gifted children, were compared for their recognition and graphic reproduction abilities. It was found that, independent of input modality, level of intelligence determined recognition performance, while graphic ability independent of IQ was the determining factor in reproduction accuracy.

Art and accuracy: the drawing ability of idiot-savants

The accuracy and the artistic merit of drawings produced by graphically gifted idiot-savants and by artistically able normal children were investigated in various conditions. Drawings had to be executed when a three- or two-dimensional model of the scene to be drawn was in view, or when it had to be remembered or drawn from another viewpoint. It was found that overall accuracy was better for the normal than for the mentally handicapped subjects. In contrast, ratings for artistic merit did not differentiate the groups. It is concluded that while the accuracy of drawings may be related to intelligence, the artistic quality of the graphic production is not.

Intelligence and musical improvisation

We investigated whether somebody with a severe mental impairment could not only remember and reproduce music, but was also able to generate it. Musical improvisation requires the ability to recognize constraints and also demands inventiveness. Musical improvisations on a traditional, tonal and also on a whole tone scale composition were produced by a mentally handicapped and by a normal control musician. It was found that not only the control but also the handicapped subject could improvise appropriately within structural constraints, although with the tonal music the idiot-savant showed some stylistic latitude. It is concluded that cognitive processes such as musical input analysis, decision making, and output monitoring are independent of general intellectual status.

The memory structure of autistic idiot-savant mnemonists

The memory organization of six autistic mnemonists was investigated in two experiments. The first of these provided some evidence that the material of special interest to the subjects, in the present instance bus numbers, was stored in memory in a categorized form. The second study showed that though the idiot-savant mnemonists did not differ from controls in the level of their general memory performance, the factor structure of a number of memory tests differed between the groups. In contrast to the controls, a verbal memory factor which seemed independent of measured verbal IQ was operative in the mnemonist subjects.

Low intelligence and special abilities

In summary, our research enables us to conclude that specific talents are found in people who differ widely in general intelligence levels and such talents should therefore be regarded as at least partly intelligence-independent. However, between normal and mentally handicapped populations and even within the idiot savant group, general cognitive capacity plays some part in determining the manner in which talents manifest themselves. Idiot savant special abilities can neither be regarded as the sole consequence of practice and training, nor are such skills based only on an efficient rote memory. Instead, idiots savants use strategies which are founded on the deduction and application of rules governing the material upon which their special ability operates. They also generate novel or new examples of such rule based structures just as we do in our use of language. Because of the much greater prevalence of idiots savants in the autistic than in the mentally handicapped population, some characteristic common to both autism and specific giftedness might be assumed. An obsessional pre-occupation with a limited section of the environment might be a common factor to both. It may be this rather than autism itself which is relevant to the idiot savant phenomenon.

Phorbol ester-induced protein kinase C translocation and lysosomal enzyme release in normal and cystic fibrosis fibroblasts

The ability of the tumor-promoting phorbol ester 4 beta-phorbol 12 beta-myristate 13 alpha-acetate (PMA) to induce protein kinase C (PKC) translocation and lysosomal enzyme release was examined in skin fibroblasts from normal subjects and from patients with cystic fibrosis (CF). As compared to normal fibroblasts, those CF exhibited: (i) an increased sensitivity to the effect of PMA on the disappearance of PKC from cytosolic fractions as well as a greater and earlier recovery, in the membrane fraction, of the PKC activity lost in the cytosolic fraction; (ii) an earlier response to PMA for its effect on beta-N-acetylglucosaminidase release. In contrast, the inactive phorbol ester 4 alpha-phorbol 12,13-didecanoate (4 alpha PDD) proved ineffective in inducing PKC translocation and beta-N-acetylglucosaminidase release in both normal and CF fibroblasts. The data suggest a defect in the regulation of PKC activity in CF fibroblasts, which may lead to altered secretion.

Visual memory and motor programmes: their use by idiot-savant artists and controls

Artistically gifted children of normal intelligence and idiot-savant artists as well as two groups of IQ-matched controls were tested for their perception of and recognition memory for shapes. They were also tested for their capacity to graphically reproduce the shapes on sight (copying) or from memory. The material consisted of designs of two levels of complexity and structure. Results showed that while IQ was the determining factor in matching and recognition performance, copying and reproduction ability depended on artistic ability and was independent of level of intelligence. These results are interpreted in terms of access to an intelligence-independent system of graphic representations which can evoke appropriate motor programmes.

Musical inventiveness of five idiots-savants

Accounts of musical ability in idiots-savants have up till now been confined to stressing the astounding musical memory which such persons may possess. The present study investigates compositional and improvisational skills in five idiots-savants. The findings interpreted as indicating that a representational system of musical rules and structures is accessible to persons of low general intelligence, and that such a system may underlie reproductive as well as generative musical capacity.

Visual and graphic abilities of the idiot savant artist

Five idiots savants whose artistic output was judged to be at art school entrance standard were matched for performance and verbal IQ with control subjects who had no special artistic talent. Each subject was given tests of reproductive skill with both concrete pictures and unfamiliar and unnameable geometric designs. They were also asked to draw a man, and a test of picture completion was given which involved constructive imagination. In all tests the idiots savants proved clearly superior to IQ-matched controls, indicating the presence of an IQ-independent talent. The results are interpreted in terms of a superior image memory and ready access to a 'picture lexicon'. In addition, the existence of superior graphically directed motor programmes must be assumed.

Idiot savant calendrical calculators: rules and regularities

The three experiments described aimed to establish whether the achievements of idiot savant calendrical calculators were based solely on rote memory and arithmetical procedures, or whether these subjects also used rule-based strategies. It was found that, although different structural calendar regularities were tested by using differing experimental paradigms, all subjects could at least use some of the rules under investigation. The more cognitively able subjects could make use of all the three structural regularities of the calendar tested here. It was concluded that idiot savant calendrical calculators can use rule-based strategies to aid them in the calculation of the days on which past and future dates fall.

Idiot savant calendrical calculators: maths or memory?

Eight idiot savant calendrical calculators were tested on dates in the years 1963, 1973, 1983, 1986 and 1993. The study was carried out in 1983. Speeds of correct response were minimal in 1983 and increased markedly into the past and the future. The response time increase was matched by an increase in errors. Speeds of response were uncorrelated with measured IQ, but the numbers were insufficient to justify any inference in terms of IQ-independence. Results are interpreted as showing that memory alone is inadequate to explain the calendrical calculating performance of the idiot savant subjects.

Peripheral and central handicap and encoding

A linear model of information processing led to many experiments on learning difficulties in the subnormal and severely subnormal. It assumes learning can result from a break in the chain of information flow at any point but overlooks compensatory mechanisms common to a developing organism. To compensate for the model's difficulties, we compared blind and deaf children with subnormal and subnormal autistic children (i.e. localized with general cognitive incapacities). Absence of a modality led to alternative encoding strategies, but in certain circumstances they also occurred in the centrally handicapped. Reasons for the similarities and differences are discussed.