Handedness in native Amazonians

Using selected incubation conditions we have identified intermediate steps, between the first glucose transferred to protein and the appropriate substrate for glycogen synthase. Mn2+ stimulates the addition of the first, and probably, the second glucose molecule to the acceptor protein but inhibits further elongation. In the presence of Mn2+ only one radioglucosylated protein band of M(r) 42 kDa was evident. In the absence of Mn2+, two bands of 60.7 and 64.6 kDa were obtained indicating elongation of the glucan chains. After Glc6P addition a family of glucosylated proteins with higher M(r) was obtained, as reported previously. Mn2+ inhibition of the second step, is reversed by PMSF+Glc6P addition. Under these conditions a family of radioglucosylated protein bands with M(r) far in excess of 42 kDa, similar to that obtained without Mn2+, was obtained. Therefore, two different transglucosylating activities were necessary, at least, to prepare the appropriate substrate for glycogen synthase. Based on these observations the model we proposed earlier for glycogen biogenesis is modified. The original "Glycogen Initiator" implies at present two enzymatic activities, Glycogen Initiator 1 (activated by Mn2+) and Glycogen Initiator 2 (inhibited by Mn2+).     

Handedness of hypothetically psychosis-prone subjects.

It has been reported that more schizophrenic individuals than normal subjects exhibit nonrighthandedness. A group of 7,457 college students were administered a measure of handedness as well as three psychosis-proneness scales, namely, the Perceptual Aberration-Magical Ideation Scale (Chapman, Chapman, & Raulin, 1978; Eckblad & Chapman, 1983), the Impulsive Nonconformity Scale (Chapman et al., 1984), and the Physical Anhedonia Scale (Chapman, Chapman, & Raulin, 1976). The number of subjects scoring high on the Perceptual Abberation-Magical Ideation Scale or the Impulsive Nonconformity Scale (or both) exceeded the number of control subjects on the incidence of ambilateral (mixed) handedness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Handedness and the cerebral representation of speech

Hand preferences vary not discretely but continuously and the continuum of preference is closely and reliably linked with a continuous roughly Normal distribution of differences between the hands in skill. Questions about handedness can be usefully formulated in terms of the distribution of differences in skill and in terms of the theshold or criterion which divided those likely to be classified as right handers from those likely to be classified as left handers. A theory of the origin of hand preferences suggests that three factors are involved. The first in non-genetic accidental variation in the development of the two sides of the body in all bilaterally symmetrical species showing limb preferences. The second in a systematic bias to the right hand in man, probably linked with the tendency for the left hemisphere to serve speech. The third is socio-cultural factors affecting the expression of sinistrality. An explanation of the relation between hand preference and cerebral speech laterality requires the assumption that in some individuals the factor biasing speech to the left hemisphere is absent. This would imply that the bias is not a universal species character but that it is subject to genetic variation. Making the simplest possible further assumptions that in the absence of bias, the laterality of handedness and of cerebral speech are independent and each governed by chance, it is possible to account for the distribution of right and left handers with dysphasias following right and left unilateral cerebral lesions.     

Handedness and the risk of tardive dyskinesia

1. We investigated whether contractile responses evoked by 5-HT1D receptor agonists were influenced by the endothelium (E) and nitric oxide (NO) in the rabbit isolated saphenous vein. 2. Saphenous vein rings were set up for isometric tension recording in oxygenated (5% CO2 in O2) Krebs solution (pH 7.4) containing (10(-6) M): idazoxan (1), indomethacin (10), ketanserin (0.1), prazosin (10), and N(omega) nitro-L-arginine methyl ester (L-NAME; 0 or 10), a NO synthase inhibitor. In some experiments, the E was removed mechanically. 3. 5-Hydroxytryptamine (5-HT), 5-carboxamidotryptamine (5-CT) and sumatriptan (Sum) contracted rabbit saphenous vein rings in the potency order (pD2 range) of 5-CT(7.2-7.6) > 5-HT(6.2-7.1) > Sum(5.0-5.8), irrespective of the presence or absence of the E or L-NAME (n = 9-37 per group) indicating that the potencies of the 3 agonists were not significantly affected by either the E or L-NAME. 4. Efficacy, as assessed by the maximal contractile response (Emax), was significantly greater for Sum compared to 5-HT and 5-CT with intact E irrespective of the presence (77 +/- 3, 62 +/- 3, and 50 +/- 3 mN respectively; P < 0.05 Sum versus 5-HT and 5-CT) or absence (26 +/- 3, 14 +/- 4, and 13 +/- 2 mN respectively; P < 0.05 Sum versus 5-HT and 5-CT) of L-NAME. In E-denuded rings, the Emax values were all higher than in E-intact rings and did not differ between the 3 agonists (36 +/- 4, 37 +/- 4, and 36 +/- 5 mN for Sum, 5-HT and 5-CT, respectively; P > 0.5 between the 3 agonists) indicating that an endothelium-derived relaxing factor (EDRF) counteracted the constrictor activities of the 5-HT1D receptor agonists and raising the possibility that a component of the Sum-induced contractile responses was E-dependent. Without E, the presence of L-NAME did not significantly affect the Emax values of the 3 agonists (41 +/- 4, 41 +/- 5, and 41 +/- 4 mN for Sum, 5-HT, and 5-CT respectively; P > 0.5 between the 3 agonists) indicating that the NO synthase inhibited was of endothelial origin. 5. Potentiation of the Emax of the 3 agonists by L-NAME was significantly albeit partially reversed by L-arginine (10(-2) M) indicating that NO synthase was indeed inhibited by L-NAME. Furthermore, in the presence of E, potentiation of Emax of the 3 agonists by L-NAME was mimicked by methylene blue (10(-5) M) providing further evidence that NO was involved in the attenuation by the E of the contractile responses induced by the 5-HT1D receptor agonists. 6. In the presence of an intact E and L-NAME, contractile responses elicited by 5-HT and Sum were competitively antagonized by the non-selective 5-HT1D receptor antagonist, methiothepin (pA2: 9.4 and 8.8; slopes: 0.66 and 0.81, respectively) and the highly selective 5-HT1D receptor antagonist, GR 127935 (pA2: 9.0 in each case; slopes: 1.04 and 0.93, respectively) indicating that contractions were mediated through activation of a single population of 5-HT1D receptors. Contractile responses elicited by 5-CT were also competitively antagonized by methiothepin and GR 127935, but non parallel rightward shifts of the concentration-response curves were observed suggestive of the involvement of additional but as yet unidentified receptors in mediating the 5-CT-induced responses. 7. In conclusion, the efficacy, but not the potency, of 5-HT, 5-CT and Sum in evoking 5-HT1D receptor-mediated contractile responses are subject to a substantial inhibitory influence of the E and of an EDRF (probably NO).     

Handedness and "automatization" cognitive style.

Evaluated the relation between "automatization" cognitive style and handedness, or degree of preferred-nonpreferred hand differentiation. 58 male undergraduates were tested on 8 cognitive tasks representing both automatized and nonautomatized abilities. After ipsatization of scores, 14 Ss were chosen as representing "strong automatization," and 14 Ss as "weak automatizers." All Ss were given 6 tests of manual performance using both preferred and nonpreferred hands. No differences were found between strong and weak automatizers in the degree of differentiation between overall preferred and nonpreferred hand performance. Explanations for these findings and the possible role of automatization cognitive style in hand differentiation in young children are discussed. (French summary) (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intelligence, Memory, and Handedness in Pedophilia.

A sample of 473 male patients with pedophilia (assessed by the patients' sexual history and penile response in the laboratory to standardized, erotic stimuli) or other problematic sexual interests or behaviors received brief neuropsychological assessments. Neuropsychological measures included a short form of the Wechsler Adult Intelligence Scale--Revised (D. Wechsler, 1981), the Hopkins Verbal Learning Test--Revised (R. H. B. Benedict, D. Schretlen. L. Groninger. & J. Brandt, 1998), the Brief Visuospatial Memory Test--Revised (R. H. B. Benedict, 1997), and the Edinburgh Handedness Inventory (S. M. Williams, 1986). Pedophilia showed significant negative correlations with IQ and immediate and delayed recall memory. Pedophilia was also related to non-right-handedness even after covarying age and IQ. These results suggest that pedophilia is linked to early neurodevelopmental perturbations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Handedness and asymmetry of hand representation in human motor cortex

The cortical representation of five simple hand and finger movements in the human motor cortex was determined in left- and right-handed people with whole-head magnetoencephalography. Different movements were found to be represented by spatially segregated dipolar sources in primary motor cortex. The spatial arrangement of neuronal sources for digit and wrist movements was nonsomatotopic and varied greatly between subjects. As an estimator of hand area size in primary motor cortex, we determined the smallest cuboid volume enclosing the five dipole sources within the left and right hemisphere of each subject. Interhemispheric comparison revealed a significant increase of this volume in primary motor cortex opposite to the preferred hand. This asymmetry was due to a greater spatial segregation of neuronal dipole generators subserving different hand and finger actions in the dominant hemisphere. Mean Euclidean distances between dipole sources for different movements were 10.7 +/- 3.5 mm in the dominant and 9.4 +/- 3.5 mm in the nondominant hemisphere (mean +/- SD; P = 0. 01, two-tailed t-test). The expansion of hand representation in primary motor cortex could not simply be attributed to a greater number of pyramidal cells devoted to each particular movement as inferred from current source amplitudes. The degree of hemispheric asymmetry of hand area size in the primary motor cortex was correlated highly with the asymmetry of hand performance in a standardized handedness test (r = -0.76, P < 0.01). These results demonstrate for the first time a biological correlate of handedness in human motor cortex. The expansion of hand motor cortex in the dominant hemisphere may provide extra space for the cortical encoding of a greater motor skill repertoire of the preferred hand.     

Handedness and performance variability as factors influencing mirror movement occurrence

The priming effects of graphemically similar (e.g., HOSE) and graphemically dissimilar (e.g., ROWS) rhymes on the naming of target words (NOSE) were examined at prime-target stimulus onset asynchronies (SOA) of 36, 70, and 250 msec. A four-field presentation procedure was used of mask-prime-mask-target. The effects of rhyme primes were measured relative to those of nonrhyming control primes (CHEF, DISH) that matched the rhymes in frequency and length and shared no letters in the same positions. At SOAs of 36 and 70 msec, rhyme priming was inhibitory and equal for graphemically similar and graphemically dissimilar rhymes. At SOA = 250 msec, rhyme priming was insignificant with a tendency toward facilitation. The results are discussed in the context of (1) contrasting effects of complete versus partial phonological overlap within a prime-target pair, and (2) the hypothesis that phonological codes stabilize fastest and provide, therefore, the earliest and major constraint on word recognition.     

Handedness and the asymmetric dynamics of bimanual rhythmic coordination.

Human handedness was investigated in a 1:1 interlimb rhythmic coordination in which consistent and inconsistent left-handed and right-handed individuals oscillated hand-held pendulums. Mean phase difference (φstable) and its standard deviation (SDφ) were evaluated as functions of mode of coordination (in-phase vs anti-phase) and the symmetry conditions imposed by controlling the natural frequencies of the left and right pendulums. The dependencies of φstable and SDφ on coordination mode and imposed symmetry were found to be systematically affected by handedness. The data were consistent with an elaboration of the established order parameter dynamics of interlimb rhythmic coordination. The elaboration includes additional 27π periodic terms that break the symmetry of those dynamics when the natural frequencies of the component rhythmic units are identical. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Patterns of Handedness in Modern Japanese: A Cohort Effect Shown by Re-administration of the H. N. Handedness Inventory After 20 Years.

The H. N. Handedness Inventory, originally administered to a sample of 1199 Japanese students in 1973, was administered to a new sample of 1700 Japanese students 20 years later. It was found that the population of left-handed and ambidextrous females had increased. The incidence of inverted left-hand writers was very small. Comparison of the two sets of data demonstrates the effects of non-biological factors upon lateral preference. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Handedness measured by finger tapping: A continuous variable.

258 boys and 225 girls (ages 5 yrs 1 mo to 13 yrs 2 mo) were shown how to tap with the index finger using a tapping apparatus and were then asked to tap as fast as possible. Handedness was established by asking S to show how he/she would perform each of several activities. Left/right differences in performance were found to be linearly related to preference as expressed by laterality quotients. The differences were distributed symmetrically about their mean but deviated significantly from a normal distribution in terms of kurtosis. Results support M. Annett's (see record 1977-20225-001) finding that handedness is a continuous variable. (French summary) (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Handedness in first-episode psychotic patients and their first-degree biological relatives.

We evaluated the handedness of 58 schizophrenia patients and 54 of their relatives, 23 patients with major depression with psychosis and 24 of their relatives, 36 patients with bipolar psychosis and 33 of their relatives, and 119 nonpsychiatric Ss and 42 of their relatives. Computerized tomography measures were also available for a subset of the psychotic patients. The schizophrenia patients were significantly more left-handed than any of the other groups, and increased sinistrality was also associated with larger lateral ventricle to brain area ratios. The relatives of the schizophrenia patients did not significantly differ on handedness from either the relatives of the affective psychosis patients or the nonpsychiatric Ss. Findings do not support the notion that left-handedness in schizophrenia is genetically influenced. More research with larger family member data sets is warranted to further explore this possibility. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Handedness and approach-avoidance behavior in chipanzees (Pan).

The relationship between hand preference and approach–avoidance behavior was examined in 49 chimpanzees (Pan). Ss were presented with 2 sets of novel objects on 4 consecutive days. The objects were presented for 2 hrs during each session, and latency to touch any object was recorded for each S. Latency scores were then compared for chimpanzees that had been determined to be non-right- or right-handed. Right-handed Ss approached and touched the objects significantly faster than non-right-handed Ss did. In addition, males touched the objects significantly faster than did females. Correlations in approach–avoidance behavior were significant across stimulus sets and days of testing. The overall results support recent theoretical models linking hemispheric specialization with the expression of positive and negative affective behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The economics of ordering inventory

Supplies constitute a major overhead expense in every dental practice. The real cost of supplies includes the ordering cost, the carrying cost and the acquisition cost. At the ideal ordering volume, the impact of these three factors is minimized and the lowest true cost in realized. This article describes two formulas that will help dental practices in determining their correct ordering volume and making accurate purchase decisions. Practices can achieve significant cost reductions by using these two simple techniques.     

Is Handedness Recognition Automatic? A Study Using a Simon-Like Paradigm.

The authors used a modified Simon task (J. R. Simon, 1969) to assess the automatic recognition of handedness. Participants responded to the color of a circle in the center of the photograph of a right or a left hand, displayed in the center of the computer screen. A regular Simon effect was found for back views, whereas a reverse Simon effect was found for palm views. This pattern of results was found when the forearm was present (Experiment 2), when 1 finger at a time was rendered invisible (Experiment 3), and when the hands were connected to a body image (Experiment 4). When the hands were cut at the wrist, no effect emerged (Experiment 1). These findings suggest an automatic encoding of the relative position of the hand in relation to the body (imaginary or real) rather than the automatic encoding of handedness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Handedness and sex differences in selective interference of verbal and spatial information.

To investigate handedness and sex differences in the way verbal and spatial information is coded in selective-interference tasks, 24 left- and 30 right-handed (as assessed by a handedness questionnaire) undergraduates were required to recall both letters and their positions in a matrix under 3 different kinds of interpolated conditions: visual, auditory, and noninterpolated activities. Results indicate that the selective-interference effect differed in right- and left-handers. Identity information had a dual encoding for both handedness groups, but it was relatively more biased toward visual encoding in left- than in right-handers; position information, however, was predominantly visually encoded to the same extent in both groups. Findings are interpreted as supporting the view that the differences in coding manner of right- and left-handers are related to differences in their hemispheric specialization. (42 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex and the single interest inventory: The empirical validation of sex-balanced interest inventory items.

Provides empirical evidence to show that it is possible to construct a valid interest inventory consisting primarily of items that have been pretested for sex balance. Potentially sex-balanced items were developed and pretested with 220 college-bound high school seniors. Items from the pretest that were sex-balanced and that showed "good" item characteristics were included on the sex-balanced Unisex Interest Inventory (Uni-II). Both the Uni-II and the American College Testing Interest Inventory (ACT-IV) were then administered to a national sample of 1,902 students. Comparisons were made between the 2 inventories on item and scale sex balance. The items on the Uni-II were more sex-balanced than those on the ACT-IV. Similarly, the Uni-II exhibited superior scale sex balance. Same-scale item homogeneity, correlational analysis, and spatial configural analysis supported the concurrent and construct validity of the Uni-II. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An assertiveness inventory for adults.

Developed the Adult Self-Expression Scale, a 48-item, self-report measure of assertiveness designed for use with adults in general. The scale was administered to 464 students at a large, "open-door" community college; Ss ranged in age from 18-60 yrs, with a mean age of 25.3 yrs. Results show the scale has high test-retest reliability and moderate-to-high construct validity, as established by correlations with Adjective Check List scales and by a discriminant analysis procedure. Factor analysis generally supported the model used in the construction of the scale. Concurrent validity was also established. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eating disorder inventory in the assessment of psychosocial status in the obese patients prior to and at long-term following biliopancreatic diversion for obesity

Psychological traits of obese patients, assessed with the Eating Disorder Inventory (EDI), were compared to those of subjects in the long-term following biliopancreatic diversion for obesity (BPD), when body weight has been steadily normal for over 1 year and any preoccupation with dieting and weight has been completely abandoned. The overall results suggest that the stable body weight normalization on a completely free diet does confer considerable psychological benefit on obese individuals. On the basis of the EDI results, post-BPD subjects were divided into weight-preoccupied and not-weight-preoccupied individuals. In the not-weight-preoccupied subjects, the psychosocial status and emotional rectivity were closely similar to those observed in lean control persons, whereas the few weight-preoccupied subjects, in spite of completely normal body weight, showed residual body dissatisfaction and personality traits very similar to those of eating-disordered patients.     

Falsification of the forced-choice guilt inventory.

Administered D. Mosher's Forced-Choice Guilt Inventory (FCGI) to 70 male adjudicated delinquents. All Ss took the test under standard instructions and then under "fake bad" and "fake good" instructions. Results were significantly different under the 3 conditions. Ss had high guilt scores under the good condition and low scores under the bad. Standard condition scores were not highly related to the other scores. The difference in scores in the bad and good conditions was significantly related to IQ, indicating that only brighter Ss could fake successfully on the test. It is concluded that the FCGI is a useful research tool, but that caution must be exercised in evaluation when used as a diagnostic tool. (PsycINFO Database Record (c) 2010 APA, all rights reserved)