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Gamma oscillations of 30-70 Hz in local electroencephalograms (EEGs) were observed in primary visual cortex (V1) of monkeys when they viewed coloured stimuli under conditions which were not part of a training paradigm. No oscillatory modulations were detected in simultaneously recorded spike trains, although the latter responded to the stimuli. The oscillations had much longer latencies than the spike responses. Proceeding in a "reverse" manner, the oscillations were taken as primary elements of the analyses, and relationships to the accompanying behaviour were sought. Besides colour stimulation, the oscillations were found to be related to a form of annoyance. Only two of four monkeys showed the phenomena. We conclude that the oscillations had a central origin.

Response patterns recorded with 30 microelectrodes from area 17 of anaesthetized monkeys are analysed. A proportion of the patterns are used to define prototype response patterns. These in turn are used to recognize the stimulus from further non-averaged response patterns. In comparison, recognition by a feedforward 'neural network' is much slower, and slightly inferior. The excitation time structure, with a resolution of about 20 ms, is found to contribute strongly to the recognition. There is some inter-ocular recognition for oriented moving bars, and for on and off phases of switched lights, but none for colours. Generalizations over some stimulus parameters (i.e. cases of confusion) are examined: If small jerking shapes are incorrectly recognized, in general the jerk direction often is the correct one. The onset of a response can most easily be found by determining the dissimilarity relative to spontaneous activity in a sliding window.

It is shown that hidden Markov models (HMMs) are a powerful tool in the analysis of multielectrode data. This is demonstrated for a 30-electrode measurement of neuronal spike activity in the monkey's visual cortex during the application of different visual stimuli. HMMs with optimized parameters code the information contained in the spatiotemporal discharge patterns as a probabilistic function of a Markov process and thus provide abstract dynamical models of the pattern-generating process. We compare HMMs obtained from vector-quantized data with models in which parametrized output processes such as multivariate Poisson or binomial distributions are assumed. In the latter cases the visual stimuli are recognized at rates of more than 90% from the neuronal spike patterns. An analysis of the models obtained reveals important aspects of the coding of information in the brain. For example, we identify relevant time scales and characterize the degree and nature of the spatiotemporal variations on these scales.

The arrangement of centromeres, cluster formation and association with the nucleolus and the nuclear membrane were characterized in human lymphocytes during the course of interphase in a cell-phase-dependent manner. We evaluated 3,893 cell nuclei categorized by five parameters. The centromeres were visualized by means of indirect immunofluorescent labeling with anti-centromere antibodies (ACA) contained in serum of patients with CREST syndrome. The cell nuclei were classified as G0, G1, S, G2, G1' and early S' phase by comparing microscopically identified groups of cell nuclei with flow cytometric determination of cell cycle stage of synchronized and unsynchronized lymphocyte cell cultures. Based on a discrimination analysis, a program was devised that calculated the probability for any cell nucleus belonging to the G0, G1, S, G2, G1' and early S' phase using only two microscopic parameters. Various characteristics were determined in the G0, S, and G2 stages. A transition stage to S phase within G1 was detected. This stage shows centromere arrangements not repeated in later cell cycles and which develop from the dissolution of centromere clusters in the periphery of the nucleus during G0 and G1. S phase exhibits various non-random centromere arrangements and associations of centromeres with the nucleolus. G1' and early S' phase of the second cell cycle display no characteristic centromere arrangement. The duplication of centromeres in G2 is asynchronous in two phases. For all cell phases a test for random distribution of the centromeres in the cell nucleus was performed. There is a distinct tendency for centromeres to be in a peripheral position during G0 and G1; this tendency becomes weaker in S phase. Although the visual impression is a seemingly random distribution of centromeres in G2 and G1', statistical analysis still demonstrates a significant deviation from random distribution in favor of a peripheral location. Only the early S phase of the second cell cycle shows no significant deviation from a random distribution.

A new triosephosphate isomerase (TPI) variant is described in an 8-year-old Turkish girl suffering from chronic haemolytic anaemia, myopathy and developmental retardation since early infancy. The enzyme activity profile revealed a generalized deficiency in erythrocytes, granulocytes, mononuclear blood cells, skeletal muscle tissue and cerebrospinal fluid. The concentration of enzyme substrate dihydroxyacetone phosphate was distinctly elevated. Biochemical examination showed accelerated enzyme deamidation, the first step in the normal catabolism of TPI during aging of the erythrocyte. The specific activity of the variant TPI, determined by antibody titration, was reduced to 61% of normal. Its heat stability was markedly decreased. Muscle biopsy and neuropsychological testing further clarified the pathogenesis of the disorder. A prevalent alteration of mitochondria similar to that seen in mitochondrial myopathy and an elevated amount of intracellular glycogen were found. The patient's retarded intellectual development was mainly due to impaired visual perception and sensory-motor co-ordination in addition to a lack of syllogistic reasoning. The findings indicate that the low TPI activity leads to a metabolic block of the glycolytic pathway and hence to a generalized impairment of cellular energy supply.

Peaks in more than 5000 spike train correlograms, obtained from monkey striate cortex, were measured. Earlier work had shown qualitatively that there are frequent prominent peaks having widths in a range around 50 ms, and narrower peaks less than about 7 ms wide. Here we demonstrate that the distribution of peak widths shows a dichotomy.

It has been suggested that the mitochondrial DNA (mtDNA) of all present-day human beings stems exclusively from one woman who lived about 200000 years ago in Africa; examination of the problem by the mathematical theory of random walks supposedly renders alternatives very unlikely. However, a statistical argument first used by Fisher indicates that this hypothesis is untenable, at least if the assumptions made by previous workers are accepted. All present-day mtDNA might go back to one individual, especially if small populations and population bottlenecks with very small numbers of reproducing individuals are assumed; nevertheless, this phase in the evolution of Homo sapiens probably dates back considerably more than 200000 years.

A 30-fold multielectrode for extracellular recording of neuronal spikes is described. Single neuronal spikes were isolated simultaneously by about half of the electrodes. The technique has been applied to demonstrate the spatial distribution of ocular dominance and orientation preference in striate cortex.

The results of psychological examinations on 298 adult male probands with various inherited EEG variants are described. They may be summarized as follows: 1) The low-voltage (N) group scored high in intelligence tests, especially in spatial orientation. Personality scores revealed this group as 'normal', extravert, group-dependent, and not very energetic. 2) The borderline low-voltage (NG) group showed slight weakness in abstract thinking, short-time memory, and motor skills and a relatively strong tendency to have 'neurotic' complaints. Reaction time and motor skills were poor. 3) The occipital fast alpha-variants (BO) group performed very well in tests of abstract thinking and motor skills. 4) The monotonous alpha (R) group showed average performance in most intelligence scores but above-average in short-time memory and in precision under stress conditions. Personality scores indicated high spontaneous activity and toughmindedness. 5) The BG (fronto-precentral beta-group) category showed very low MMPI scores, indicating little neurotic tendency. Intelligence could be above average. 6) The diffuse beta (BD) group scored low in intelligence tests, especially in spatial orientation, and had a high error rate in tests measuring concentration and precision. Most differences were relatively small; the whole range of test scores could be found in all EEG groups.

A female turkish infant with congenital infantile genetic agranulocytosis was examined for its distribution of lymphocyte subclasses. Imbalances of B cells and T-cell subpopulations were found. Compared to the normal control group a relative as well as an absolute deficiency of T helper cells and an increase of the absolute number of T suppressor cells were the most prominent findings. The importance of immunoregulatory T-cell subsets in the pathogenesis of infantile genetic agranulocytosis, disorders of hematopoiesis and granulocyte production, as well as primary and secondary immunodeficiencies is discussed.

The problem of a possible clustering of human chromosomes containing genes with related functions was examined in the interphase nucleus of lymphocytes by a statistical comparison of distances between chromosomes containing such functionally related genes with all sets of chromosome distances. The gene locus assignments were taken from a recent review (McKusick 1982); the chromosomal distances were those estimated by Hager et al. (1982) from the frequencies of reunion figures between specific chromosomes as observed in chromosome instability syndromes (Fanconi anemia, Bloom syndrome) and after treatment with Trenimon. Chromosomal distances had been estimated by multidimensional scaling. There was no general tendency for closer location of chromosomes containing genes with related function. A few such chromosomes do show below average distances but this could easily be a chance result.

From six flaxedilized rhesus monkeys neuronal activity of 75 cells in the dorsal, and 45 cells in the ventral layers of the lateral geniculate body was recorded. Responses to large fields switched on and off, to moving slits, and to moving spots were obtained for several wavelengths. In the dorsal layers, colour selectivity was strong for large field stimuli but weak for moving spots. Residual colour selectivity for spots was more evident for smaller eccentricities. In comparison, ventral layer cells were less colour selective for all stimuli used. Large field responses were weak, they often consisted of a sequence of excitation and inhibition. The subdivision of the dorsal cells into different colour opponency types based on large field responses is compared to the subdivision based on centre and surround functions. Results are compared to colour responses in retina and visual cortex, and the tonic and phasic cell type subdivision is discussed.

The resting EEGs of 17 twin pairs originally traced through one neurotic co-twin (10 monozygotic and 7 dizygotic pairs aged between 18 and 63 years) have been described and compared with the neuroticism scores (Schepank, 1974) of these twins. EEG comparison according to the customary visual criteria failed to show any consistent EEG differences between monozygotic co-twins, whereas dizygotic pairs often showed EEG discordance. Computerized time-domain (interval-amplitude) analysis failed to show a higher degree of EEG discordance between neurotic MZ co-twins than between co-twins in 25 adult nonneurotic male MZ pairs (age range 18--33; mean age 22.9 years). There were no significant correlations between EEG differences and differences in the neuroticism score among ten MZ pairs traced through a neurotic co-twin. It is concluded that the individual and genetically determined EEG pattern is manifest even in the face of the long-lasting psychological alterations observed in neurotics.

Recordings from the visual cortex of anaesthetized monkeys taken with a 30-fold multi-microelectrode demonstrate that the neuronal variability, defined as the change in response strength over time spans of a few seconds to several minutes, is highly correlated within groups of neurones. Several such groups exhibiting independent variability between groups, coexist within the area recorded. This within-group covariance suggests that a major part of neuronal variability is due not to a noise process in the cells, but rather to additional inputs to the neurones, which are not under control of the experimenter.

Visually and auditory evoked EEG potentials were studied in 248 healthy university students, who were carriers of one of the following hereditary EEG variants: Monomorphic alpha-waves; low-voltage-EEG; EEG in which the alpha-rhythm was mixed diffusely with beta-waves; and EEG with fronto-precentral beta-groups. The study uncovered consistent and statistically significant group differences between the EEG-countertypes, monomorphic alpha-waves and the low-voltage EEG: subjects with monomorphic alpha-waves showed higher amplitudes and longer latencies of most peaks of the visually evoked potential (VEP), and higher amplitudes for most peaks of the auditory evoked potentials (AEP). Similar differences between EEG types were shown for two measures--overall amplitude (oscillation) and average latency--of all peaks for VEPs and AEPs. The results are consistent with a hypothesis discussed in an earlier paper in which differences between these two EEG types in processing of information in the CNS were assumed on the basis of psychological test results and neurophysiological theory. The two EEG types with beta-waves in addition to alpha-waves showed latencies of evoked potentials in-between those found in the EEG types with monomorphic alpha-waves, on the one hand, and the low-voltage EEG on the other. There was no significant difference in the frequency of VEP augmenters and reducers between EEG types.

3H-L-Dopa was given to rats after a peripheral decarboxylase inhibitor Ro 4-4602 (50 mg/kg) and the effect of 30 min pretreatment with antiptyline (10 mg/kg), desipramine (10 mg/kg) and imipramine (10 mg/kg) on the brain formation of 3H-dopamine, 3H-noradrenaline and their major metabolites was investigated. Desipramine produced a decrease in the level of labelled noradrenaline and its major metabolites free and conjugated 3-methoxy-4-hydroxyphenyleneglycol and 3,4-dihydroxyphenyleneglycol. Imipramine decreased labelled noradrenaline and 3-methoxy-4-hydroxyphenyleneglycol, whereas amitriptyline produced no significant effect on noradrenaline metabolism. The thymoleptic drugs produced no significant effect on endogenous brain noradrenaline and dopamine. These findings provide a strong indication that desipramine and imipramine inhibit the 3H-noradrenaline biosynthesis from 3H-L-Dopamthe effect seems closely related to the well-known membrane inhibitory effect of these drugs, since desipramine produced a more marked effect than imipramine and amitriptyline showed no effect. No conclusive evidence for the precise mechanism of action was obtained but it is possible that the decreased 3H-noradrenaline synthesis is related to interference of desipramine and imipramine with the precursor (s) 3H-L-Dopa or 3H-dopamine at sites of 3H-noradrenaline biosynthesis.

In 974 patients with chicken pox (varicellae) from four large children's hospitals in Germany, a weak association with blood groups A (and probably AB) was found.

In the first section of this paper, various research designs in human behavior genetics are compared. In this context, the commonly used concept of biometric genetics is critically evaluated from the point of view of science theory. It is contrasted with the Mendelian gene concept, which, in principle, leads to a much deeper theoretical understanding by offering clues for basic mechanisms. To explore this advantage fully, a research strategy is needed that first looks for genetic variability in a physiological parameter of possible importance for human behavior and then tries to explore the influence of this parameter on the function of the human brain and on behavior. If possible, this genetic parameter should be selected in a way that inferences as to the mechanism of its influence on behavior become feasible. Such genetic variability is provided by the hereditary variants of the normal EEG discovered by earlier work (cf. Vogel, 1970). In the following section, a research program on 298 adult healthy males, most of them soldiers, with various inherited EEG variants is described. Apart from controls with inconspicuous EEGs, this material comprises probands with the following EEG variants: low-voltage (N); low-voltage borderline (NG); monotonous alpha-waves (R); occipital fast alpha-variants (BO); fronto-precentral beta-groups (BG), and diffuse beta-waves (BD). In addition to an EEG examination, the probands were examined with various test methods measuring intelligence (IST; LPS; Raven); working speed and concentration (d-2; KLT); personal attitudes (MMPI; 16PF; RKS); and sensory and motor abilities (flicker fusion; tachistoscopy; reaction time to optic, acoustic and combined stimuli; two-hand dexterity; pursuit rotor; tapping). In a supplementary twin study on 52 male adult twin pairs (26 MZ, 26 DZ), heritabilities were determined for the test scores included in the main study. For most test scores, heritabilities are relatively low; the data are compared with those from the literature. We conclude that the test methods utilized in the main study (on EEG variants) are expected to demonstrate at the most a small to moderate correlation of the EEGs with psychological phenotypes as defined by test examinations, even if a major part of the genetic variability underlying these phenotypes would be due to differences in brain physiology that could be revealed by EEG variation.

As part of an overall assessment of immunological function, several aspects of cellular immunity and circulating lymphocyte subpopulations were evaluated in a group of 10 patients with idiopathic autoimmunhemolytic anemia (AIHA). The absolute numbers of circulating T and B cells were reduced in the patient group compared to normals. A shift from "corticosteroid-sensitive" to "corticosteroid-resistent" and activated cells in the cytogram of clustered Fe-(III)-hydroxide-glucane saccharose labeled T lymphocytes was apparent. In vitro studies of cellular reactivity, as evaluated by PHA, ConA, PWM, antigens and allogeneic cell induced proliferation showed a blend of general or selective depression and sometimes a normal or increased activity with no definite correlation with both the number of circulating T cells and the extent of the hemolytic activity by the disease. The possible significance of the findings is discussed.

A hypercolumn of monkey striate cortex was studied with an array of 30 closely spaced microelectrodes. Prominent broad peaks appearing in spike train correlograms are considered here. These were not due to shared stimulation, were mostly 30 to 100 ms wide, and were presumably the consequence of intraretinal lateral interactions. The correlogram peak areas were found to be predictable from the products of the spike rates, to which they were proportional. One can conclude that the correlation occurs before the overall reduction of spike rates from retina to cortex takes place. Furthermore, when a neurone dominated by one eye was stimulated via that eye, the correlogram formed with a neurone dominated by the other eye showed a displaced peak, indicating that excitation traveled from the well-responding to the unresponsive neurone in about 10 ms. When a left-eye stimulus was delivered, the same pair of neurones had a correlogram with a reversed peak displacement. This effect was only observed in layers IVb and c, indicating that in these layers the paths from the two eyes to a given cell are of unequal length, whereas in other layers, cells receive input from both eyes via similar connections differing only in strength.

Activity from single neurons in the visual cortex of anaesthetized and paralyzed cats were recorded in response to monocular and binocular stimuli of different retinal disparities. Three different types of disparity sensitive neurons were found, characterized by (1) a response maximum near zero disparity, (2) a response minimum near zero disparity, and (3) an asymmetric disparity sensitivity. Usually, neurons of the first type receive about the same monocular input from the two eyes; the other disparity sensitive neurons respond better to monocular stimulation of one eye as compared to the other. The results closely resemble those obtained recently in the rhesus monkey.

Thirteen patients with primary immunodeficiency disorders and their twenty-five healthy first-degree relatives were tissue typed and their HLA make-up was compared with that of a normal control population. HLA-A2 occured in 92.3% of patients as opposed to 60.8% in the control group (P less than 0.02), HLA-A9 in 7.6% vs. 25% (P less than 0.02) and HLA-B8 in 0% vs. 21% (P less than 0.04). One of the patients with severe combined immunodeficiency showed one "extraneous" HLA specifity.

Responses to sudden shifts of a pattern far away from the receptive field (shift-effect) were found in 73 out of 81 cells of the ventral, magnocellular LGN layers, but in only 26 out of 85 cells of the dorsal, parvocellular layers. Most of the former responses were clear and excitatory, and most of the latter were weak and inhibitory. Excitatory responses were stronger for steady receptive field illumination which when turned on also yielded an excitation. No convincing dependence on the colour of the receptive field illumination was observed. The results are discussed with respect to the hypothesis of transmission of steady illumination via the shift-effect ("restoration"), and with respect to a hypothesis assigning a signaling function of low stimulus specificity to the ventral layers.

In a female infant with severe combined immunodeficiency disease extraneous HLA specificities were found which could neither have been inherited from the father nor the mother. The case is reported in detail and a survey of the literature with similar observations is given. The different explanations of this phenomenon are discussed.

26 patients with an acute reversible ITP and 6 with chronic ITP were tissue typed, together with their healthy first-degree relatives. The HLA frequencies of the different groups were compared with those of a normal control population. The only significant difference between the groups was an increase in the frequency of Aw32 in acute ITP patients. HLA-Aw32 was present in 26.9% of patients, but in only 0.8% of the controls (corrected P = 0.000027). The possible importance of associations between antigens of the HLA-A locus with certain diseases are discussed. Family analyses and haplotype determinations proved to be unproductive because no familial clustering of ITP was found.

To verify the reliability of secretor status for prenatal diagnosis of myotonic dystrophy (DM), 179 amniotic fluid samples were compared with saliva or urine samples of the infants by hemagglutination inhibition. While no discrepancies were observed, problems could arise with intermediate results. Additionally, secretor typing is only informative in 8.4% of patients.

The Ss sialoglycoprotein (glycophorin B) and its antigens in Rhnull erythrocytes, which lack the Rhesus blood group antigens, due to apparently silent (amorphic type) or independent suppressor (regulator type) genes, were investigated. The quantity of the molecule in amorphic and in regulator type red cell membranes was found to be decreased by about 60%-70%, as judged from sodium-dodecylsulfate polyacrylamide gel electrophoresis. The Ss glycoprotein content in the erythrocytes from heterozygotes (regulator type) was diminished to an extent of about 30%. Confirming and extending previous studies, the S, s, Ux, Uz and 'N' antigens were slightly weakened in Rhnull erythrocytes. The U and Duclos receptors were only slightly or not depressed in amorphic Rhnull cells, but almost absent from or not detectable in those of the regulator type. This demonstrates that an additional alteration, apart from the decreased Ss glycoprotein content of the membranes, accounts for the weakness of these receptors in regulator type cells. We propose the hypothesis that (a) protein(s) encoded by the Rhesus locus form(s) a complex with the Ss glycoprotein. Thus, it (they) might facilitate the incorporation of the Ss glycoprotein into the membrane and also contribute to the complete expression of the U and Duclos antigens in normal cells.

During continuous movement of a large global pattern remote from the classical receptive field retinal ganglion cells discharge considerably faster (continuous shift effect), and center responses are decreased in amplitude for neurons with a relatively high ongoing activity (mostly ON-center) but increased for neurons with no ongoing discharge (mostly OFF-center). The results suggest that all retinal ganglion cells have more or less access to one long range mechanism, which is non-linear and almost all-or-none in nature.

Levels of immunoglobulins G, A and M and complement factor C3 and C4 were determined by single radial immunodiffusion techniques in a group of 26 children with a history of postinfectious thrombocytopenic purpura and in another group of 6 children with chronic ITP. The statistical evaluation of the data of patients with chronic ITP did not show any significant deviation from normal. In patients with previously acute, reversible ITP, levels of IgG and IgM were elevated. Whether this elevation was significant or not depended upon the statistical analysis applied. C3 levels tended to be above the average normal mean, C4 levels, in contrast, to be below. The importance of increased IgG and IgM concentrations in patients with the history of postinfectious ITP is discussed. The raised IgG and IgM levels are interpreted as an expression of a certain type of hyperimmune state rather than as an impairment of immunoregulatory mechanisms.

In this study, the hypothesis was tested whether there is any relationship between measures of intelligence and working speed on the one hand, and characteristics of visually or auditory evoked EEG potentials, on the other. The study was performed on two samples: 1. In 236 University students selected for presence of four different, inherited EEG variants, product-moment correlations were computed between test scores for various aspects of mental performance on the one hand, and two measures of averaged visual and auditory evoked EEG potentials (VEPs and AEPs), on the other. The two EP measures were the average latency of all identifiable peaks between 70 and 600 ms after stimulation; and the "oscillation", a combined measure of amplitudes, comparable to Hendrickson's "string measure". Moreover, correlations were computed between two selected test scores (IQ and Raven) on the one sides, and the amplitudes and latencies of the components named P1, N1, and P2 by Buchsbaum on the other. 2. Twenty-four adults with mental retardation of unknown origin, inmates of an institution for the mentally retarded, were compared with 19 normal controls matched for age and sex - there were no consistent positive correlations between the characteristics of VEPs and AEPs and any of the performance measures studied. Hence, the hypothesis that there are consistent correlations between oscillation and latency of EPs and measures of mental performance was not confirmed. There is no convincing overall explanation for the discrepancies between various results reported in the literature but some of them may be explained either by individual differences in EEG maturation among children, or by additional sensoric input in some series, or by admixture of subjects with organic brain damage in some of the series, or by the individual characteristics of the resting EEG - a parameter that had been neglected in all previous studies.

In this paper various new findings on the possible anatomical substrates of tardive dyskinesia will be presented. The results show that the striatum is heterogeneously organized, and the syndromes of biting, gnawing, and licking activities in the rat model involve a complex balance between various dopamine (DA), cholinergic, and GABAergic systems within the striatum and the mesolimbic and mesocortical systems.

As evidenced by a large pedigree with 21 affected members, acrokeratoelastoidosis (AKE) is an autosomal dominant skin disease (10185; McKusick 1978). Linkage with genetic markers already assigned to human chromosomes could help to map the gene for this disease. Therefore 22 markers were investigated in 61 members of the AKE family. Loose linkage is possible between AKE and ACP1, IGKC, and Jk, but the estimated recombination fractions do not reach significant deviations from 0.5. However, since the three marker loci have been previously assigned to chromosome 2, the AKE locus might be assigned tentatively to the same chromosome. Of the provisionally and inconsistently assigned markers, only blood group P is seen to be in linkage with HLA.

Family, twin, and adoption studies have shown that genetic factors are involved in the etiology of alcoholism. Based on earlier EEG findings in alcoholics and on the known genetic determination of the alcohol effect on the EEG, the hypothesis was tested whether the resting EEG reflects a certain disposition to alcoholism. Resting EEGs were examined for 115 alcoholics (78 males, 37 females) and matched controls. In addition, the first-degree relatives of two extreme groups of alcoholics--those with poor and those with particularly good alpha waves--were examined and compared with matched controls. The EEGs were analyzed with an EEG processor. Whereas male alcoholics did not differ from their controls, female patients showed a shift from the alpha and theta to the beta bands of the brain wave pattern. The relatives of the two extreme groups of alcoholics, who did not misuse alcohol, exhibited the same tendency. This is an argument supporting the notion that in females a poorly synchronized EEG pattern reflects a certain disposition to alcoholism. This finding is discussed in light of drinking motivation in males and females. The latter more often belong to the alpha- and gamma-types of alcoholism than do males. Because of comparable findings in schizophrenics it is argued that a genetically determined desynchronized resting EEG pattern is not specific for a certain illness, but reflects basic mechanisms that enhance the risk for different psychiatric disorders.

In order to test the hypothesis that the high prevalence of the mar(X) syndrome is caused by a high mutation rate in male germ cells only, the fraction of new mutants among mothers of probands in 112 informative families has been examined by segregation analysis among their brothers and sisters. The estimated fraction of new mutants among these mothers is much lower than expected if a stable equilibrium existed between an unusually high mutation rate and a selective disadvantage of mentally retarded, male and female mar(X) carriers. Hence, the above-mentioned hypothesis could not be confirmed.

In a pilot study, the possible influence of the inherited electroencephalogram (EEG) pattern on aspects of psychologic maturation was investigated. The twin sample consisted of 208 pairs, 110 monozygotic (MZ) and 98 dizygotic (DZ), mostly children and adolescents. The study showed a greater similarity between MZ compared with DZ twins in an immaturity score constructed from the Baum test (Koch 1976) and in a teacher's maturity scoring of essays. For both parameters, a correlation between occipital alpha-frequency and the test criterium could be demonstrated. This correlation was in the direction expected, and it was significant statistically. This result suggests an influence of genetically determined variation of brain maturation on interindividual variability of psychologic variation. Due to shortcomings of the methods used in the study, more specific conclusions cannot be drawn; the problem needs further elucidation using modern methods.

Unlabelled: The formal genetics of Fanconi's anemia were investigated on the basis of 21 families from different European countries, and of 69 families from the literature., Conclusions: 1. The result of segregation analysis is compatible with the hypothesis of a simple autosomal recessive mode of inheritance. 2. The number of sporadic cases is not greater than expected. 3. Among the affected siblings in the sibships analyzed, males are somewhat more frequent than females. However, this sex difference is also found among the unaffected siblings, and it is not statistically significant. 4. Contrary to assertions made in the literature, there is no clustering of affected in the sequence of siblings, no maternal age effect, and no preference of higher birth orders. 5. A high intrafamilial correlation for age at onset, and (very probably) number and severity of malformations points to genetic heterogeneity. Apart from the standard type, an especially mild type with late onset, few malformations, and a relatively benign course seems to exist. Its counterpart is possibly an especially severe type with early onset, many malformations, and a malignant course. However, definite conclusions on the special character of this heterogeneity will require application of additional methods.