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Some extracellular-signaling peptides also at times function within the intracellular space. We have termed these peptides intracrines and have argued that intracrine function is associated with a wide variety of peptides/proteins including hormones, growth factors, cytokines, enzymes, and DNA-binding proteins among others. Here we consider the possibility that intracrines participate in the related phenomena of senescence, apoptosis, and stem cell regulation of tissue biology. Based on this analysis, we also suggest that the concept of intracrine action be expanded to include possible regulatory peptide transfer via exosomes/microvesicles and possibly by nanotubes. Moreover, the process of microvesicular and nanotube transfer of peptides and other biologically relevant molecules, which we inclusively term laterality, is explored. These notions have potentially important therapeutic implications, including implications for the therapy of cardiovascular disease. atherosclerosis; laterality

This study assessed bilateral facilitation and laterality during counter-movement jumps. 23 NCAA Division-I athletes (13 men, 10 women) who participated in track and field volunteered to serve as participants and performed bilateral, right, and left leg countermovement jumps on a force plate. Dependent variables included jump height, reactive strength index, and time to stabilization. A one way analysis of variance showed significant sex differences in single-leg and bilateral jump height and left leg and bilateral reactive strength index. No sex differences were found for time to stabilization. A repeated-measures analysis of variance indicated significant main effects for jump height and reactive strength index but not for time to stabilization. Bonferroni adjusted pairwise comparisons showed that bilateral jump height and reactive strength index values were different from the unilateral conditions. No differences were found between the right and left legs for jump height, reactive strength index, or time to stabilization. Results indicated no evidence of laterality as assessed by jump height, reactive strength index, and time to stabilization. Bilateral facilitation was found as assessed by jump height and reactive strength index. Time to stabilization demonstrated a bilateral deficit phenomenon.

Visual analogue scales are commonly used to measure the intensity of sensations, and their validity and reliability have been reported. However, biases similar to those found in visual line bisection have not been investigated. 23 right-handed and 19 left-handed participants, with a mean age of 30.1 yr., marked three points on a visual analogue scale representing imagined pain, using both the left and right hands, corresponding to 1/4, 1/2, and 3/4 of the way across the scale. In keeping with visual line bisection literature, both right- and left-handed participants marked the scale with the left hand significantly leftward of the point marked with the right hand, thereby underreporting the intensity. Right-handed participants marked 1/4 significantly leftward and 3/4 significantly rightward of veridical points, thereby underreporting and overreporting, respectively, the intensity. However, left-handed participants did not display this bias and consistently erred leftward for 1/4, 1/2, and 3/4 positions, underreporting intensity. These findings were explained in terms of hemispheric specialisation and activation for a manual response to a visuospatial task, with the conclusion that scoring the visual analogue scale to millimetre accuracy is subject to a potential confound of these factors.

Human handedness, a marker for language lateralization in the brain, continues to attract great research interest. A widely reported but not universal finding is a greater male tendency toward left-handedness. Here the authors present a meta-analysis of k = 144 studies, totaling N = 1,787,629 participants, the results of which demonstrate that the sex difference is both significant and robust. The overall best estimate for the male to female odds ratio was 1.23 (95% confidence interval = 1.19, 1.27). The widespread observation of this sex difference is consistent with it being related to innate characteristics of sexual differentiation, and its observed magnitude places an important constraint on current theories of handedness, In addition, the size of the sex difference was significantly moderated by the way in which handedness was assessed (by writing hand or by other means), the location of testing, and the year of publication of the study, implicating additional influences on its development. Kevwords: handedness, sex differences, meta-analysis, laterality, hand preference

Understanding the evolutionary origins of hemispheric specialization remains a topic of considerable interest in a variety of scientific disciplines. Whether nonhuman primates exhibit population-level limb preferences continues to be a controversial topic. In this study, limb preferences for ascending and descending locomotion were assessed as a means of examining the hypothesis that asymmetries in forelimb bones might be attributed to asymmetries in posture. The results indicated that captive chimpanzees showed a population-level leftward asymmetry in descending locomotion but no group bias for ascending locomotion. The results are consistent with previous behavioral studies in captive chimpanzees as well as studies on skeletal asymmetries of the forelimbs of chimpanzees. KEY WORDS laterality; posture; locomotion; chimpanzees

The authors examined the effects of task complexity and posture on laterality and compared lateralization during different tasks in 9 captive grey-cheeked mangabeys (Lophocebus albigena) during spontaneous food processing and 3 experimental tasks. Comparisons with data of red-capped mangabeys (Cercocebus torquatus torquatus; semiterrestrial species) were used. Less than half the monkeys were lateraiized for simple everyday activities, but 6 were lateralized for complex daily activities. Moreover, all the monkeys were lateralized when performing experimental tasks. Laterality at the group level was found for the bipedal task: Mangabeys were right-handed. Complexity of tasks increases laterality at the individual level. Significant differences between the 2 species of mangabeys were found, allowing us to confirm that postural constraints are a major factor in the emergence of group handedness. Keywords: laterality, Lophocebus albigena, posture, task complexity

Historically, population-level handedness has been considered a hallmark of human evolution. Whether nonhuman primates exhibit population-level handedness remains a topic of considerable debate. This paper summarizes published data on handedness in great apes. Comparative analysis indicated that chimpanzees and bonobos show population-level right handedness, whereas gorillas and orangutans do not. All ape species showed evidence of population-level handedness when considering specific tasks. Familial analyses in chimpanzees indicated that offspring and maternal (but not paternal) handedness was significantly positively correlated, but this finding was contingent upon the classification criteria used to evaluate hand preference. Overall, the proportion of right handedness is lower in great apes compared with humans, and various methodological and theoretical explanations for this discrepancy are discussed. Keywords: handedness, great apes, laterality, behavior genetics

The purpose of this study was to examine the relation of practice or learning and-laterality on the Purdue Pegboard and the Moving Beans with Tweezers test. The subjects were 30 right-handed, healthy young male adults (age: M = 21.1> SD = 1.9 yr.). The subjects performed both tests five times with each hand. A two-way analysis of variance (hand x trial) for scores on the Purdue Pegboard showed that Trial 1 had a significantly lower mean than Trials 4 and 5 with the dominant hand, and scores on Trials 1 and 3 were lower than that on Trial 5 for the nondominant hand. For the Moving Beans with Tweezers test, Trial 1 had a significantly lower score than Trial 5 with the nondominant hand. The dominant hand produced significantly higher values on all trials of both tests. Intraclass correlation coefficients of Trials 2 and 3 were high, and means were significantly higher for the dominant hand. A correlation between other tests was not high (r = .37-.46) for both hands. All correlations among five trials on both tests were significant and high (Purdue Pegboard-Dominant: average r=.72, |r| .60-.80, Purdue Pegboard-Nondominant: average r.59, |r| = .43-.76), (Moving Beans-Dominant: average r = .74, |r| = .57-.81, Moving Beans-Nondominant: average r =.71, |r| = .55-.87). Correlations among five trials for the ratio of dominant:nondominant hand on both tests were significant and moderate (Moving Beans: average r-.28, |r|-.08-.57, Purdue Pegboard: average r =.41, |r|=.19.56). Performance with the dominant hand is superior to that of the nondominant hand on both tests. Practice effects are found for both tests across five trials. The Moving Beans with Tweezers test also showed laterality of practice effects. The two tests may measure different abilities.

ABSTRACT. Symmetry of skill development is emphasized in dance training, and many movements are well learned by both genders. The authors conducted a 2-dimensional kinematic analysis of a complex dance [...]

Previous research has shown that sex differences exist in the composition of lateral movements (E. F. Field, I. Q. Whishaw, & S. M. Pellis, 1996, 1997a, 1997b). An unresolved question is whether sex differences are present in other movements, such as rotation around the longitudinal axis, and whether this difference is dependent on a feminine or masculine skeletomusculature. Female rats (Rattus norvegicus) first rotate their forequarters and then their hindquarters in the same direction. Male rats exhibit rotation of the hindquarters counter to the direction of forequarter rotation. Males with the testicular feminized mutation, who have a feminized skeletomusculature and masculinized central nervous system, are similar to male controls. This study provides evidence that sex differences in movement integration are not restricted to the lateral plane, are not solely due to sex differences in skeletomusculature, and thus are likely mediated by the central nervous system.

This study concerns the distribution of footedness among professional soccer players (n=415) and nonsporting university students (n=430). Chi-squared showed that there were statistically significant differences between the proportion of mixed-footedness in the two groups (p

Performance degradations in multitasking situations have been reported frequently as a predictable effect of competition that arises from different processing demands whose hemispheric locations are too proximal. This model might be useful in explaining performance deficits in complex workplaces. To test this assertion, a laboratory study was designed to create an analogue of the processing demands required by a tactical decision-making task performed by 24 right-handed men. Vocalization, dichotic listening and decision-making performance were assessed under single- and dual-task conditions. The results were consistent with the predictions from hemispheric competition in the case of dichotic listening but not with vocalization. The results are discussed in terms of their implications for both research and systems design.

Of the neurobiological models of children's and adolescents' depression, the neuropsychological one is considered here. Experimental and clinical evidence has allowed us to identify a lateralization of emotional functions from the very beginning of development, and a right-hemisphere dominance for emotions is by now well-known. Many studies have also correlated depression with a right hemisphere dysfunction in patients of different ages. The aim of our study was to analyze recognition of different facial emotions by a group of depressed children and adolescents. Patients affected by Major Depressive Disorder recognized less fear in six fundamental emotions than a group of healthy controls, and Dysthymic subjects recognized less anger. The group of patients' failure to recognize negative-aroused facial expressions could indicate a subtle right hemisphere dysfunction in depressed children and adolescents.

Common marmosets (Callithrix jacchus) with a right-hand preference displayed shorter latencies to enter a novel room containing novel structures and objects, touched more objects, and performed more touches and more parallax movements than marmosets with a left-hand preference. These results are consistent with specialization of the right hemisphere (left hand) for fear and negative emotional states and specialization of the left hemisphere (right hand) for approach and positive emotional states. There were no effects of age or sex on any of these behaviors. This relationship between exploration and hand preference did not occur when the marmosets were tested in the home cage with a novel problem, although significant effects of both age and dominance were found in solving the problem.

INTRODUCTION The issue of cerebral lateralization for communicative competence has provoked much research. The current view is that the left hemisphere is dominant for language in most right-handers, whereas the [...], The ability of right-brain-damaged (RBD) patients to use on-line contextual information in a word-monitoring task was examined. Subjects were required to monitor for target words in the contexts of both normal and semantically anomalous sentences. Similar to previous studies with normals (e.g., Marslen-Wilson & Tyler, 1980), the semantic integrity of the context was influential in the word-recognition process. Importantly, the RBD patients performed similarly to normals in showing context effects. These results were interpreted as substantiating the findings of Leonard, Waters, and Caplan (1997a, 1997b) that RBD patients do not present with a specific deficit in the use of contextual information. The results are discussed in terms of proposals that suggest that an impaired ability to use contextual information by RBD patients may be a function of increased processing demands.

In contrast to the extensive literature on hand, foot, and eye preferences there are only a few studies concerning ear preference. From a review of 27 studies 13 items (Stopwatch, Telephone receiver, Tablecloth, Head movement, Wall, Drawer, Wall phone, Heartbeat, Door, Earphone, Box, Pocket radio, Voice) were identified in the measurements of ear preference. In a series of investigations, these self-report items were validated with respect to individual behavioural measures and test-retest reliabilities were obtained over 1 mo. and 1 yr. for earedness. These data indicate that a questionnaire composed of these items could be a valid and reliable method for the assessment of various forms of ear preference, but there are several differences among the items in validity and reliability.

The hypothesis that reading disability is associated with impairment in the lateralization of temporal stimuli was tested by presenting 123 good- and poor-reading boys (Grades 4 through 6) with dichotic sets of temporal and nontemporal tonal stimuli for recognition. Reading ability was assessed by measuring proficiency in reading consonants, vowels, words, sentences and short stories. On the tone test, good readers showed a right-ear advantage in reporting the temporal stimuli, and a left-ear advantage in reporting the nontemporal stimuli. Poor readers showed the reversed pattern of response. Since right-ear advantage in report of given stimuli indicates left-hemispheric dominance for processing those stimuli, the data seem to suggest a link between reading disability and left-hemispheric dysfunction in processing temporal stimuli.

Some previous studies have suggested that alcoholics exhibit selective right-hemisphere dysfunction, based on alcoholics' poor performance on tests believed to subserve the right hemisphere. However, some of these experiments did not account adequately for differences in difficulty or novelty in putative right hemisphere tasks. This experiment was designed to evaluate and compare intermanual differences in grip strength, motor speed, fine-motor dexterity, and nonverbal problem-solving ability in 93 recently detoxified alcoholics, 54 long-term abstinent alcoholics, and 73 nonalcoholic controls. All subjects were right-handed men, matched for age and education, and both alcoholic groups had similar drinking histories. Using percent difference scores to assess intermanual differences, adjusted for demographics where appropriate, we found that, although recently detoxified alcoholics demonstrate some motor and psychomotor impairments, there is no evidence using these tests to suggest the right hemisphere is selectively more vulnerable to the effects of chronic alcohol abuse.

Right-left orientation, mental rotation, and perspective-taking were examined in a group of 406 subjects ranging from 5 to 11 yr. of age with equal numbers of children in each age group. Immediate recognition was not a difficult task as even young children succeeded adequately on the three tasks involving different images. Right-left identification, where right and left terms are used, was harder even for the oldest subjects when associated with mental rotation. When children had to identify which image a person would see from another viewpoint, they succeeded when the person was looking away in the same direction as they were looking. When the person was facing the children (in the opposite direction or 'forward'), three different behaviors emerged which indicated absence or presence of mental rotation in perspective-taking. Young subjects chose images as if the figures in the image were seeing from the subject's viewpoint; this percentage diminished slowly across increased ages. As subjects' ages increased, more chose the correct image. Even at 11 years of age, however, only half of the subjects chose correctly. Finally, an equal percentage of subjects among the different age groups understood that the person was seeing a different orientation of the persons but did not associate this with the correct right-left position of the persons on the image. This transition most probably reflects the slow evolution of cognitive processes which determine the way the child will use references to internal or external frameworks. It illustrates as well the passage from egocentrism to geo-centrism with the ability to consider viewpoints other than one's own.

Is hemispheric specialization for speech more closely related to left hemisphere specialization for manual skill and sequencing, as is usually supposed, or to control of asymmetries in whole body posture, as recent findings of right-handedness in nonhuman primates suggest? This question can be evaluated in the 10% of humans who have mixed handedness and footedness. Footedness entails postural asymmetry, and persons with mixed limb preferences often prefer the hand ipsilateral to the preferred foot in asymmetrical actions for which whole body postural adjustments are obligatory (e.g., throwing). The dichotic listening test, an indicator of language laterality, was administered to 4 groups of 48 persons with the 4 possible combinations of hand and foot preference. As in 2 past studies, language lateralization was somewhat more strongly related to postural asymmetries than to asymmetries in manual skill and sequencing.

Foot preference and performance characteristics of gross-motor lower-limb speed of tapping were examined in 606 4- to 6-yr.-olds. Analysis indicated no effect for gender; however, speed of foot tapping increased significantly across the three ages, suggesting an association with selected developmental (neuromuscular) processes. Contrary to earlier reports on handedness, there was no statistical evidence that mixed- or left-footers were at a performance disadvantage compared to right-footers. All groups performed best with the right foot, limb differentiation (right versus left) being significant for the right- and mixed-footed groups. Speculation about maturational and environmental influences is given.

The prevalence of difficulties in left-right discrimination was investigated in a group of 2,720 adult members of the high-IQ societies Mensa and Intertel. Over-all, 7.2% of the men and 18.8% of the women evaluated their left-right directional sense as poor or below average. Participants who were relatively ambidextrous experienced problems more frequently than did those who were more strongly left- or right-handed. Age differences were also evident, with participants age 17-29 reporting the highest rate of problems, and participants age 60 and over reporting markedly lower rates than those age 30-59. The observed patterns of gender differences were maintained within these age- and strength-of-handedness subdivisions. The basis for selecting the items that form the handedness inventory used is discussed.

Prior research has shown that right-handed adults perform better on a speed-tapping task with the right hand and right foot, while left-handers execute more rapidly with the left hand and right foot. Speculation is that environmental influence, most likely driving experience, may account for the right-foot bias. To examine this hypothesis further, 48 young right- and left-handed children were tested on a similar protocol. Analyses indicated no significant differences in foot performance within hand-preference groups. Since these findings do not complement reports for adults, factors such as experience or maturation might contribute to the difference. Were patterns similar, the effect of environmental influence would be assumed to be small. However, much more evidence is needed before an adequate explanation can be developed. The issue of possible environmental influence is discussed from various theoretical perspectives.

The tendency of women to prefer to hold infants on the left side of the body has been confirmed by several methods: surveys of works of art and of photographs, field observations, and experimental methods. The present study developed a new method to examine the patterns of child-holding, that is, the child-holding thought experiment. 2287 female and 1268 male undergraduates were instructed to imagine nursing or feeding a baby. Then, they were asked on which side of the body they imagined holding the baby. Seventy-two percent of the women and 65% of the men reported imagining holding a baby on the left side of the body. This preference for the left side was noted, irrespective of handedness. These results indicate that both women and men who have never fed their own babies prefer to imagine holding a baby on the left side of the body. Moreover, that the magnitude of this preference was significantly stronger for the women adds to the evidence of a gender-dependent expression for lateral preferences in holding a baby.

Measurements involving responses on a left-right scales are common in market research practice. This paper investigates natural right and left-handed tendencies in ordering stimuli, and discusses the issues they raise [...]

There are basically two tachistoscopic techniques by which questions can be asked experimentally in normal subjects about how cognitive variables affect the way the hemispheres intercommunicate. A first approach, the [...], Experimentation with unilateral and bilateral tachistoscopic stimulation (the Dimond paradigm) increasingly suggests that interhemispheric cooperation (bilateral advantage) occurs or increases as a function of task complexity in general and memory load in particular. However, tachistoscopic experimentation with ipsilateral and contralateral field/hand relation conditions (the Poffenberger paradigm) has failed to provide any conclusive supporting evidence. The present investigation comprised a Sternberg 'high speed memory scanning' task, modified as a go/no-go task, and formatted into the Poffenberger paradigm. Sets of items to be scanned (memory load) varied in size from one to four. A highly significant effect of load and a significant field/hand interaction were found, but the field/hand/load interaction did not reach significance. We concluded that the interhemispheric transfer time (ITT) metric drawn from this paradigm is not reliably sensitive to increasing memory load. However, our finding of significantly longer ITT in women than in men suggests that commissural anatomy and physiology may be sexually dimorphic.

Right-left orientation includes discrimination and recognition as well as identification, the former two differentiating between symmetrical cues and the latter using the words right and left. In the present experiment involving 406 children, the evolution of the knowledge and use of the concepts of right and left were assessed. Discrimination and recognition on all tasks used in this study are mastered much earlier than verbal identification, and, at even 11 years of age, half of the subjects of the present study still did not apply the words right and left properly onto other persons in the milieu. Children use the words right and left correctly first on their own bodies as early as seven years of age, then on people facing away, and finally on people facing them around eight to nine years of age. This transition most probably reflects the slow evolution of cognitive processes which determine the way the child will use internal or external frameworks as well as the passage from egocentrism to 'alteregocentrism' with ability to consider other viewpoints than one's own.

Sensory integration and interaction are essential aspects of the perceptual process. As a result, impairment in one sensory modality might be expected to have some effect on perceptual functioning in [...], This research examines visual field differences in the detection and identification of a peripheral stimulus for deaf and hearing subjects, as a function of concurrent foveal stimulation. Deaf and hearing subjects were presented with peripheral target stimuli (simple geometric shapes) presented tachistoscopically to the left or right visual fields under four conditions of foveal stimulation: (a) no stimulus; (b) simple geometric shapes; (c) pictorial shapes (outline drawings); and (d) orthographic letters. Dependent measures were detection response latency and peripheral shape recognition (errors). With error data, hearing subjects showed a right field advantage under foveal conditions of no stimulus and simple shape stimulus, but a left field advantage with pictorial and letter foveal stimuli. Deaf subjects showed the opposite effect, with a left field advantage under foveal conditions of no stimulus and simple shape stimulus, but a right field advantage with pictorial and letter foveal stimuli. Latency data revealed the same pattern of results for hearing subjects, but no significant visual field differences for deaf subjects. Results are interpreted in terms of differences in hemispheric visual processing used by deaf and hearing subjects, as affected by varying conditions of foveal load.

This study attempts to determine the effects of intonation morphemes in French on the processing of simple reversible sentences containing a dislocated element. Synthetic speech stimuli were used. Subjects (80 children aged 5.0 and 6.0 and 48 adults, all monolingual, native French speakers) generally processed the sentences better when they retained the standard subject-verb-object order characteristic of most French utterances. When that order was not maintained, appropriate intonation promoted the correct attribution of roles in sentences with a dislocated object. The on-line analysis of adult response timing suggested that intonation morphemes serve as processing instructions for these subjects, guiding them in deciding whether to express their answer immediately or to delay responding. [C] Academic Press, Inc.

Handedness among architects was determined by mail survey. Contrary to previous reports, no evidence was found of an excess of left-handers among a sample of 236 fully qualified male architects and 78 male architectural students. A second study examined whether the use of mail surveys systematically biases the returns of handedness questionnaires. For this, questionnaires were sent to 1,017 university students. No evidence was found for a bias amongst those who did and did not reply to the initial questionnaire. These results strengthen the findings of the first study. La dominance manuelle chez les architectes etait determinee par sondage postal. Contrairement a ce qui avait ete rapporte, il n'y avait pas d'evidence d'un plus grand nombre de gauchers dans l'echantillon compose de 236 architectes males diplomes et de 78 etudiants en architecture males. Une deuxieme etude examinait si l'utilisation des sondages postaux biaisait systematiquement les retours des questionnaires sur la dominance manuelle. Ces questionnaires furent envoyes a 1,071 etudiants d'universite. Aucune evidence ne fut trouvee quant a un biais parmi ceux qui ont et ceux qui n'ont pas repondu au questionnaire initial. Ces resultats renforcent ceux obtenus dans la premiere etude.

A young left-handed girl with an extensive posttraumatic lesion in the left hemisphere was tested with dichotic listening (DL) under three different attentional instructions. The major aim of the study was to evaluate a structural vs attentional explanation for dichotic listening. As both her expressive and receptive language functions were intact after the lesion, it was assumed that the right hemisphere was the language-dominant one. In the free-report condition, she was free to divert attention to and to report from both ear inputs. In the forced-right condition, she was instructed to attend to and report only from the left-ear input. Her performance was compared with data from a previously collected sample of normal left-handed females. Analysis showed that the patient, in contrast to the normal sample, revealed a complete right-ear extinction phenomenon, irrespective of attentional instruction. Furthermore, she showed superior correct reports from the left ear, comparedd with those of the normal sample, also irrespective of attentional instruction. It is concluded that these results support a structural, rather than attentional explanation for the right-ear advantage (REA) typically observed in dichotic listening. The utility of validating the dichotic listening technique on patients with brain lesions is discussed.

Three experiments were carried out to investigate people's memory for British coins. Two principal issues were studied. First, it has previously been shown that memory for U.S. pennies and other coins is surprisingly imperfect. How do other countries compare? It turned out that recall of the design of British pennies was, if anything, worse even than that of U.S. pennies. The situation was no better for a larger coin with an unusual shape. It is suggested that individual features are poorly remembered if they have low levels of meaningfulness, redundancy, identifiability, and discriminativeness. Second, in addition to this generally weak level of remembering, an instance of systematic misremembering was consistently observed. The Queen's portrait always faces to the right on British coins. Yet in all three experiments, the proportion of participants who recalled that the portrait faces to the right was so low (overall, 19%) that it was significantly less than even the 50% baseline to be expected from people in a state of complete ignorance. It follows that the participants were not in a state of complete ignorance. Rather, they relied upon extraneous knowledge of either a general or a specific nature (bias and schema hypotheses, respectively), whose importation into this domain was in fact invalid. The resulting belief that coin portraits face left was not right.

The effects of stimulus rotation and observer's head-tilt position on various pattern-recognition tasks were investigated to compare the external directions most closely aligned with the spatial frame of reference. Specifically, the effects of these factors on the time to name objects were compared with their effects on the time to discriminate left-facing from right-facing lateral views of these objects, as well as with their effects on the time to discriminate normal from mirror-imaged alphanumeric characters. The naming task relied upon a reference frame more closely aligned with retinal directions than with environmental directions. In contrast, both discrimination tasks relied upon a frame aligned more closely with enviromental directions. Overall, the nature of the task exerts a greater influence on the directions with which the frame of reference is aligned than do the stimulus attributes.

In most of the neuropsychological studies the left-right hemifacial asymmetry during expression of emotion has been reported, although the present author proposed a concept of hemiregional asymmetry and reported that greater left hemifacial involvement was specific to the lower region of the face and greater right hemifacial was specific to the upper region of the face. It is speculated that this differential hemifacial involvement is a function of the right hemisphere, and it is explained in terms of neural innervation to facial muscles. This speculation needs to be verified further to arrive at a general conclusion.