1
|
Gerrits R. Variability in Hemispheric Functional Segregation Phenotypes: A Review and General Mechanistic Model. Neuropsychol Rev 2024; 34:27-40. [PMID: 36576683 DOI: 10.1007/s11065-022-09575-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 07/15/2022] [Accepted: 11/16/2022] [Indexed: 12/29/2022]
Abstract
Many functions of the human brain are organized asymmetrically and are subject to strong population biases. Some tasks, like speaking and making complex hand movements, exhibit left hemispheric dominance, whereas others, such as spatial processing and recognizing faces, favor the right hemisphere. While pattern of preference implies the existence of a stereotypical way of distributing functions between the hemispheres, an ever-increasing body of evidence indicates that not everyone follows this pattern of hemispheric functional segregation. On the contrary, the review conducted in this article shows that departures from the standard hemispheric division of labor are routinely observed and assume many distinct forms, each having a different prevalence rate. One of the key challenges in human neuroscience is to model this variability. By integrating well-established and recently emerged ideas about the mechanisms that underlie functional lateralization, the current article proposes a general mechanistic model that explains the observed distribution of segregation phenotypes and generates new testable hypotheses.
Collapse
Affiliation(s)
- Robin Gerrits
- Department of Experimental Psychology, Ghent University, Ghent, Belgium.
| |
Collapse
|
2
|
Gupta P, Ojha T, Dabaria RK, Sharma K, Chhabra B, Trivedi B, Bansal M. Left Handedness: Fair or a Fallacy. From Otorhinolaryngology Residency Training Perspective. Indian J Otolaryngol Head Neck Surg 2023; 75:474-477. [PMID: 37275036 PMCID: PMC10235275 DOI: 10.1007/s12070-022-03316-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/27/2022] [Indexed: 12/13/2022] Open
Affiliation(s)
- Priyanshi Gupta
- Department of ENT, Mahatma Gandhi Medical College and Hospital, Jaipur, India
| | - Tarun Ojha
- Department of ENT, Mahatma Gandhi Medical College and Hospital, Jaipur, India
| | | | - Kanika Sharma
- Department of ENT, Mahatma Gandhi Medical College and Hospital, Jaipur, India
| | - Biban Chhabra
- Department of ENT, Mahatma Gandhi Medical College and Hospital, Jaipur, India
| | - Bhargavi Trivedi
- Department of ENT, Mahatma Gandhi Medical College and Hospital, Jaipur, India
| | - Monika Bansal
- Department of ENT, Mahatma Gandhi Medical College and Hospital, Jaipur, India
| |
Collapse
|
3
|
Affiliation(s)
- Alan A Beaton
- Department of Psychology, Swansea University, Singleton Park, Swansea, UK.,Department of Psychology, Aberystwyth University, Ceredigion, UK
| | | | - Chris McManus
- Research Department of Clinical, Educational and Health Psychology, University College London, London, UK
| |
Collapse
|
4
|
Króliczak G, Gonzalez CLR, Carey DP. Editorial: Manual Skills, Handedness, and the Organization of Language in the Brain. Front Psychol 2019; 10:930. [PMID: 31080429 PMCID: PMC6497748 DOI: 10.3389/fpsyg.2019.00930] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 04/08/2019] [Indexed: 01/30/2023] Open
Affiliation(s)
- Gregory Króliczak
- Action and Cognition Laboratory, Department of Social Sciences, Institute of Psychology, Adam Mickiewicz University in Poznan, Poznan, Poland
| | - Claudia L R Gonzalez
- Department of Kinesiology, University of Lethbridge, Lethbridge, AB, Canada.,Department of Neuroscience, University of Lethbridge, Lethbridge, AB, Canada
| | - David P Carey
- Perception, Action and Memory Research Group, School of Psychology, Bangor University, Bangor, United Kingdom
| |
Collapse
|
5
|
Hodgson JC, Hudson JM. Speech lateralization and motor control. PROGRESS IN BRAIN RESEARCH 2018; 238:145-178. [DOI: 10.1016/bs.pbr.2018.06.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
|
6
|
Kitamura T, Suzuki H, Yokota H, Watanabe E, Yamada J. Morphological changes indicative of brain hemisphere development and handedness in fixed brains and on CT/MRI images. Okajimas Folia Anat Jpn 2017; 94:7-15. [PMID: 29213018 DOI: 10.2535/ofaj.94.7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We measured the lengths of some parts of the right and left hemispheres (HEs) in 70 formalin-fixed brains and on 15 computed tomography/magnetic resonance imaging (CT/MRI) images (7 left-handed and 8 right-handed cases) to clarify the morphological changes indicating which HE developed earlier and handedness. In many cases of the fixed brains, 1) the distance from the frontal pole to the occipital pole was longer in the left HE than in the right HE, 2) the distance from the middle plane to the lateral-most portion of the HE was wider in the right HE than in the left HE, 3) the left occipital pole elongated more posteriorly and covered the right occipital pole, and 4) the volume of each HE was nearly the same. The results indicate that the left HE develops and grows slightly earlier in the larger semi-cranium (half of the cranium) than the right HE which develops later in the smaller semi-cranium. The whole brain was more spherical in the female cases than in the male cases. The morphological changes in both HEs for handedness were not evident on the CT/MRI images.
Collapse
Affiliation(s)
| | - Hiroko Suzuki
- Department of Neurosurgery, Jichi Medical University
| | | | - Eiju Watanabe
- Department of Neurosurgery, Jichi Medical University
| | - Jinzo Yamada
- Depatment of Anatomy, Tokyo Medical University
- Department of Psychology, Kashiwazaki-kousei Hospital
| |
Collapse
|
7
|
Kavaklioglu T, Ajmal M, Hameed A, Francks C. Whole exome sequencing for handedness in a large and highly consanguineous family. Neuropsychologia 2015; 93:342-349. [PMID: 26581626 DOI: 10.1016/j.neuropsychologia.2015.11.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 11/05/2015] [Accepted: 11/10/2015] [Indexed: 12/13/2022]
Abstract
Pinpointing genes involved in non-right-handedness has the potential to clarify developmental contributions to human brain lateralization. Major-gene models have been considered for human handedness which allow for phenocopy and reduced penetrance, i.e. an imperfect correspondence between genotype and phenotype. However, a recent genome-wide association scan did not detect any common polymorphisms with substantial genetic effects. Previous linkage studies in families have also not yielded significant findings. Genetic heterogeneity and/or polygenicity are therefore indicated, but it remains possible that relatively rare, or even unique, major-genetic effects may be detectable in certain extended families with many non-right-handed members. Here we applied whole exome sequencing to 17 members from a single, large consanguineous family from Pakistan. Multipoint linkage analysis across all autosomes did not yield clear candidate genomic regions for involvement in the trait and single-point analysis of exomic variation did not yield clear candidate mutations/genes. Any genetic contribution to handedness in this unusual family is therefore likely to have a complex etiology, as at the population level.
Collapse
Affiliation(s)
- Tulya Kavaklioglu
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Muhammad Ajmal
- Institute of Biomedical and Genetic Engineering (IBGE), 24-Mauve Area, G-9/1, Islamabad, Pakistan
| | - Abdul Hameed
- Institute of Biomedical and Genetic Engineering (IBGE), 24-Mauve Area, G-9/1, Islamabad, Pakistan.
| | - Clyde Francks
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands.
| |
Collapse
|
8
|
Bishop DV, Holt G, Whitehouse AJ, Groen M. No population bias to left-hemisphere language in 4-year-olds with language impairment. PeerJ 2014; 2:e507. [PMID: 25165624 PMCID: PMC4137668 DOI: 10.7717/peerj.507] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Accepted: 07/18/2014] [Indexed: 11/20/2022] Open
Abstract
Background. An apparent paradox in the field of neuropsychology is that people with atypical cerebral lateralization do not appear to suffer any cognitive disadvantage, yet atypical cerebral lateralization is more common in children and adults with developmental language disorders. This study was designed to explore possible reasons for this puzzling pattern of results. Methods. We used functional transcranial Doppler ultrasound (fTCD) to assess cerebral blood flow during language production in 57 four-year-olds, including 15 children who had been late-talkers when first seen at 20 months of age. We categorized cerebral lateralization as left, right or bilateral, and compared proportions with each type of laterality with those seen in a previously tested sample of children aged 6-16 years. We also compared language scores at 4 years for those with typical and atypical lateralization, and then looked at the association the opposite way: comparing those with typical or impaired language in terms of their cerebral lateralization. Results. The distribution of types of cerebral lateralization was similar for 4-year-olds to that seen in older children. Overall, cerebral lateralization was not predictive of language level. However, for children who had language difficulties at 20 months and/or 4 years (N = 21), there was no population bias to left-hemisphere language activation, whereas children without language problems at either age showed a pronounced bias to left-sided language lateralization. Nevertheless, many children with right hemisphere language had no indications of language difficulties, confirming that atypical cerebral asymmetry is not a direct cause of problems. Conclusions. We suggest that atypical lateralization at the individual level is not associated with language impairment. However, lack of lateralization at the population level is a marker of risk for language impairment, which could be due to genetic or non-genetic causes.
Collapse
Affiliation(s)
| | - Georgina Holt
- Department of Experimental Psychology, University of Oxford, UK
| | - Andrew J.O. Whitehouse
- Department of Experimental Psychology, University of Oxford, UK
- Telethon Institute of Child Health Research, University of Western Australia, Perth, WA, Australia
| | - Margriet Groen
- Department of Experimental Psychology, University of Oxford, UK
- Radboud University, ED Nijmegen, Netherlands
| |
Collapse
|
9
|
Ross ED, Shayya L, Champlain A, Monnot M, Prodan CI. Decoding facial blends of emotion: visual field, attentional and hemispheric biases. Brain Cogn 2013; 83:252-61. [PMID: 24091036 DOI: 10.1016/j.bandc.2013.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 07/23/2013] [Accepted: 09/02/2013] [Indexed: 10/26/2022]
Abstract
Most clinical research assumes that modulation of facial expressions is lateralized predominantly across the right-left hemiface. However, social psychological research suggests that facial expressions are organized predominantly across the upper-lower face. Because humans learn to cognitively control facial expression for social purposes, the lower face may display a false emotion, typically a smile, to enable approach behavior. In contrast, the upper face may leak a person's true feeling state by producing a brief facial blend of emotion, i.e. a different emotion on the upper versus lower face. Previous studies from our laboratory have shown that upper facial emotions are processed preferentially by the right hemisphere under conditions of directed attention if facial blends of emotion are presented tachistoscopically to the mid left and right visual fields. This paper explores how facial blends are processed within the four visual quadrants. The results, combined with our previous research, demonstrate that lower more so than upper facial emotions are perceived best when presented to the viewer's left and right visual fields just above the horizontal axis. Upper facial emotions are perceived best when presented to the viewer's left visual field just above the horizontal axis under conditions of directed attention. Thus, by gazing at a person's left ear, which also avoids the social stigma of eye-to-eye contact, one's ability to decode facial expressions should be enhanced.
Collapse
Affiliation(s)
- Elliott D Ross
- Department of Neurology, University of Oklahoma Health Sciences Center and the VA Medical Center 127, 921 NE 13th Street, Oklahoma City, OK 73104, USA.
| | | | | | | | | |
Collapse
|
10
|
|
11
|
Cui Y, Zhang Z, Huo X, Dai J, Zheng G, Feng X, Wang C. The correlation between lateralization of intracerebral hemorrhage in basal ganglia and handedness. Acta Cir Bras 2013; 28:228-32. [DOI: 10.1590/s0102-86502013000300012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 01/18/2013] [Indexed: 11/22/2022] Open
Affiliation(s)
| | | | | | | | | | - Xu Feng
- Liaoning Medical College, China
| | | |
Collapse
|
12
|
Powell JL, Kemp GJ, Roberts N, García-Finaña M. Sulcal morphology and volume of Broca's area linked to handedness and sex. BRAIN AND LANGUAGE 2012; 121:206-218. [PMID: 22482924 DOI: 10.1016/j.bandl.2012.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 02/28/2012] [Accepted: 03/07/2012] [Indexed: 05/31/2023]
Abstract
We investigated the effect of handedness and sex on: (i) sulcal contours defining PO and PTR and (ii) volume estimates of PO and PTR subfields in 40 left- and 42 right-handers. Results show an effect of handedness on discontinuity of the inferior frontal sulcus (IFS: P<0.01). Discontinuity of IFS was observed in: 43% left- and 62% right hemispheres in right-handers and in 65% left- and 48% right-hemispheres in left-handers. PO volume asymmetry was rightward in left-handed males (P=0.007) and females (P=0.02), showed a leftward trend in right-handed males (P=0.06), and was non-asymmetrical in right-handed females (P=0.96, i.e. left- and right-hemisphere PO volumes did not differ significantly). PO volume asymmetry in males differed significantly between handedness groups (P=0.001). Findings indicate a high degree of variability in the sulcal contours of PO and PTR and volume asymmetry of PO: the factors sex and handedness can explain some of this variability.
Collapse
Affiliation(s)
- Joanne L Powell
- Magnetic Resonance and Image Analysis Research Centre (MARIARC), University of Liverpool, UK.
| | | | | | | |
Collapse
|
13
|
Rosch RE, Bishop DVM, Badcock NA. Lateralised visual attention is unrelated to language lateralisation, and not influenced by task difficulty - a functional transcranial Doppler study. Neuropsychologia 2012; 50:810-5. [PMID: 22285903 PMCID: PMC3334833 DOI: 10.1016/j.neuropsychologia.2012.01.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Revised: 10/15/2011] [Accepted: 01/12/2012] [Indexed: 12/21/2022]
Abstract
Historically, most theoretical accounts of hemispheric specialisation have proposed a single underlying factor that leads to left hemisphere language and right hemisphere visuospatial processing in the majority of people. More recently empirical evidence has started to challenge this view, suggesting lateralisation of language and visuospatial attention are independent. However, so far studies did not control for a possible confound, task difficulty. For this study, 20 healthy right-handed volunteers underwent functional laterality assessment using functional transcranial Doppler ultrasound (fTCD). We assessed laterality using both a word generation task and a novel variation of the visuospatial landmark task that can be adjusted along two dimensions of difficulty (temporal and spatial). The visuospatial laterality measures were highly intercorrelated and unaffected by task difficulty. Furthermore, there was no correlation between visuospatial and verbal lateralisation within individuals – neither qualitatively (in direction of lateralisation), nor quantitatively (in laterality index size). These results substantiate a growing body of evidence suggesting multiple independent biases leading to the hemispheric lateralisation of different cognitive domains, thus further questioning previously accepted models of laterality development and evolution.
Collapse
|
14
|
Powell JL, Kemp GJ, García-Finaña M. Association between language and spatial laterality and cognitive ability: An fMRI study. Neuroimage 2012; 59:1818-29. [DOI: 10.1016/j.neuroimage.2011.08.040] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 07/26/2011] [Accepted: 08/15/2011] [Indexed: 10/17/2022] Open
|
15
|
Gutwinski S, Löscher A, Mahler L, Kalbitzer J, Heinz A, Bermpohl F. Understanding left-handedness. DEUTSCHES ARZTEBLATT INTERNATIONAL 2011; 108:849-53. [PMID: 22259638 DOI: 10.3238/arztebl.2011.0849] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 07/12/2011] [Indexed: 11/27/2022]
Abstract
BACKGROUND The human cerebrum is asymmetrical, consisting of two hemispheres with differing functions. Recent epidemiological and neurobiological research has shed new light on the development of the cerebral lateralization of motor processes, including handedness. In this article, we present these findings from a medical perspective. METHOD We selectively searched the PubMed online database for articles including the terms "handedness," "left handedness," "right handedness," and "cerebral lateralization." Highly ranked and commonly cited articles were included in our analysis. RESULTS The emergence of handedness has been explained by physiological and pathological models. Handedness arose early in evolution and has probably been constitutive for the development of higher cognitive functions. For instance, handedness may have provided the basis for the development of speech and fine motor skills, both of which have played a critical role in the evolution of mankind. The disadvantages of certain types of handedness are discussed, as some cases seem to be associated with disease. CONCLUSION The consideration of handedness from the epidemiological, neurobiological, and medical points of view provides insight into cerebral lateralization.
Collapse
Affiliation(s)
- Stefan Gutwinski
- Klinik für Psychiatrie und Psychotherapie, Charité – Universitätsmedizin Berlin, Campus Charité Mitte, Grosse Hamburger Str. 5–11, 10115 Berlin, Germany.
| | | | | | | | | | | |
Collapse
|
16
|
Kim HS, Shin JB, Kim JM. Crossed Transcortical Motor Aphasia, Left Spatial Neglect, and Limb and Magnetic Apraxia Due to Right Anterior Cerebral Artery Infarction. Ann Rehabil Med 2011; 35:949-53. [PMID: 22506227 PMCID: PMC3309387 DOI: 10.5535/arm.2011.35.6.949] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Accepted: 04/29/2010] [Indexed: 11/10/2022] Open
Abstract
Crossed aphasia refers to language disturbance due to right-hemisphere lesions in right-handed individuals, while magnetic apraxia is described as 'forced grasping and groping' caused by lesions in the contralateral frontal lobe. This is a case report of a 70-year-old right handed woman who suffered from crossed transcortical motor aphasia and left hand magnetic apraxia due to right anterior cerebral artery infarction. The definite mechanism of this disorder is not yet understood, but neurophysiological observations suggest that affected supplementary motor areas may be responsible for this phenomenon.
Collapse
Affiliation(s)
- Hyoung Seop Kim
- Department of Rehabilitation Medicine, National Health Insurance Corporation Ilsan Hospital, Ilsan 410-719, Korea
| | - Jung Bin Shin
- Department of Rehabilitation Medicine, National Health Insurance Corporation Ilsan Hospital, Ilsan 410-719, Korea
| | - Jong Moon Kim
- Department of Rehabilitation Medicine, National Health Insurance Corporation Ilsan Hospital, Ilsan 410-719, Korea
| |
Collapse
|
17
|
Jones GV, Martin M. Language dominance, handedness and sex: Recessive X-linkage theory and test. Cortex 2010; 46:781-6. [DOI: 10.1016/j.cortex.2009.07.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 04/05/2009] [Accepted: 07/20/2009] [Indexed: 11/28/2022]
|
18
|
Gonzalez CLR, Goodale MA. Hand preference for precision grasping predicts language lateralization. Neuropsychologia 2009; 47:3182-9. [PMID: 19654015 DOI: 10.1016/j.neuropsychologia.2009.07.019] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 07/21/2009] [Accepted: 07/28/2009] [Indexed: 11/27/2022]
Abstract
We investigated whether or not there is a relationship between hand preference for grasping and hemispheric dominance for language--and how each of these is related to other traditional measures of handedness. To do this we asked right- and left-handed participants to put together two different sets of 3D puzzles made out of big or very small LEGO pieces. Participants were also given two self-reported handedness questionnaires, as well as tests of grip force and finger tapping speed. A language lateralization (dichotic listening) test was also administered. We found a positive correlation between hand use for precision grasping and language lateralization (i.e. the more participants used their right hand for grasping the small LEGO pieces, the more language was lateralized to the left hemisphere). In addition, we identified two populations of left-handers according to their grasping performance: 'left-right-handers', who behaved exactly like right-handers; and 'left-left-handers' whose performance was the mirror image of that of right-handers. Finally, we found an increase in right-hand use when right-handers and 'left-right-handers' had to pick up the small LEGO pieces. We discuss our results in relation to recent notions of left-hemisphere specialization for visually guided actions and its relationship with the evolution of language.
Collapse
Affiliation(s)
- Claudia L R Gonzalez
- CIHR Group on Action and Perception, Department of Psychology, University of Western Ontario, London N6A5C2, Canada.
| | | |
Collapse
|
19
|
Whitehouse AJO, Bishop DVM. Hemispheric division of function is the result of independent probabilistic biases. Neuropsychologia 2009; 47:1938-43. [PMID: 19428426 PMCID: PMC2706326 DOI: 10.1016/j.neuropsychologia.2009.03.005] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Revised: 01/29/2009] [Accepted: 03/04/2009] [Indexed: 11/24/2022]
Abstract
Verbal and visuospatial abilities are typically subserved by different cerebral hemispheres: the left hemisphere for the former and the right hemisphere for the latter. However little is known of the origin of this division of function. Causal theories propose that functional asymmetry is an obligatory pattern of organisation, while statistical theories maintain this is a reflection of independent, probalistic biases. The current study investigated lateralisation for language production and spatial memory using functional Transcranial Doppler in 75 healthy adults (45 right handed, 27 left-handed, 3 ambidextrous). The majority of participants had language abilities lateralised to the left-hemisphere and spatial memory to the right hemisphere, while around one-quarter of participants had these functions lateralised to the same hemisphere. No participants showed the reversal of typical organisation. The findings are consistent with a statistical view of functional asymmetry, in which hemispheric biases for verbal and visual functions reflect probabilities relating to independent causal sources.
Collapse
Affiliation(s)
- Andrew J O Whitehouse
- Telethon Institute for Child Health Research, Centre for Child Health Research, The University of Western Australia, West Perth, Western Australia, Australia.
| | | |
Collapse
|
20
|
Dorst J, Haag A, Knake S, Oertel W, Hamer H, Rosenow F. Functional transcranial Doppler sonography and a spatial orientation paradigm identify the non-dominant hemisphere. Brain Cogn 2008; 68:53-8. [DOI: 10.1016/j.bandc.2008.02.123] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2007] [Revised: 02/25/2008] [Accepted: 02/26/2008] [Indexed: 11/16/2022]
|
21
|
Annett M. Tests of the right shift genetic model for two new samples of family handedness and for the data of McKeever (2000). Laterality 2008; 13:105-23. [PMID: 17852701 DOI: 10.1080/13576500701433522] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Two new family samples are described for handedness in parents and children. In the first sample, drawn from the general population, questionnaires were completed for each individual (a self-report sample). In the second sample students completed a handedness questionnaire and described the handedness of their parents (indirect report sample). The percentages of left-handed children in the various family types (R x R, R x L etc., father x mother) were tested for goodness of fit to the predictions of the right shift genetic model, along with tests for the findings of McKeever (2000). Fits for the self-report sample were good for all family types. For the indirect report sample fits were good for many family types but there were more left-handed daughters than expected in R x L families and fewer than expected in L x R families. In the McKeever sample there was a shortfall of sons in L x R families but the fit for sons in R x L families was excellent. It is concluded that differences between samples here, and in the literature, are variable and probably due to sampling errors when the assessment of parental handedness depends on indirect report. Findings for sex differences do not suggest a need for hypotheses about X-linked mechanisms.
Collapse
|
22
|
Lux S, Keller S, Mackay C, Ebers G, Marshall JC, Cherkas L, Rezaie R, Roberts N, Fink GR, Gurd JM. Crossed cerebral lateralization for verbal and visuo-spatial function in a pair of handedness discordant monozygotic twins: MRI and fMRI brain imaging. J Anat 2008; 212:235-48. [PMID: 18304205 PMCID: PMC2408986 DOI: 10.1111/j.1469-7580.2008.00855.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2007] [Indexed: 12/13/2022] Open
Abstract
To examine the nature of hemispheric lateralization for neural processes underlying verbal fluency and visuo-spatial attention, we investigated a single pair of handedness discordant monozygotic (MzHd) twins. Imaging of the brain was undertaken using magnetic resonance imaging (MRI) and functional magnetic resonance imaging (fMRI) in combination with manual performance tasks. The twins were discordant for MRI anatomical asymmetries of the pars triangularis and planum temporale, whose asymmetry was consistent with verbal laterality on fMRI. Thus, the right-handed twin had left lateralized verbal with right lateralized visuo-spatial attention, while the left-handed twin had right lateralized verbal with left lateralized visuo-spatial activation; these data lend further support for to the conclusions of Sommer et al.
Collapse
Affiliation(s)
- Silke Lux
- Institute of Neuroscience and Biophysics, Department of Medicine, Research Centre Jülich, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
|
24
|
Abstract
We recorded the direction of hair whorl rotation in samples of male right- and non-right-handers. The data corroborate those of Klar (2003) in showing equal numbers of clockwise and anti-clockwise whorls in non-right-handers but an excess of clockwise whorls in right-handers. The findings support the view that in some proportion of the population direction of coiling arises as a consequence of random events occurring during early (pre-natal) development of the nervous system, while in the remainder of the population there is a systematic bias towards a clockwise direction of rotation. The association with handedness implies that the latter is in a very large measure biologically rather than culturally determined.
Collapse
Affiliation(s)
- Alan A Beaton
- Department of Psychology, University of Wales, Swansea, UK.
| | | |
Collapse
|
25
|
Jansen A, Lohmann H, Scharfe S, Sehlmeyer C, Deppe M, Knecht S. The association between scalp hair-whorl direction, handedness and hemispheric language dominance: is there a common genetic basis of lateralization? Neuroimage 2006; 35:853-61. [PMID: 17275334 DOI: 10.1016/j.neuroimage.2006.12.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 12/11/2006] [Accepted: 12/13/2006] [Indexed: 12/01/2022] Open
Abstract
The hemispheres of the human brain are functionally asymmetric. The left hemisphere tends to be dominant for language and superior in the control of manual dexterity. The mechanisms underlying these asymmetries are not known. Genetic as well as environmental factors are discussed. Recently, atypical anticlockwise hair-whorl direction has been related to an increased probability for non-right-handedness and atypical hemispheric language dominance. These findings are fascinating and important since hair-whorl direction is a structural marker of lateralization and could provide a readily observable anatomical clue to functional brain lateralization. Based on data on handedness and hair-whorl direction, Amar Klar proposed a genetic model ("random-recessive model") in that a single gene with two alleles controls both handedness and hair-whorl orientation (Klar, A.J.S., 2003. Human handedness and scalp hair-whorl direction develop from a common genetic mechanism. Genetics 165, 269-276). The present study was designed to further investigate the relationship between scalp hair-whorl direction with handedness and hemispheric language dominance. 1212 subjects were investigated for scalp hair-whorl direction and handedness. Additionally, we determined hemispheric language dominance (as assessed by a word generation task) in a subgroup of 212 subjects using functional transcranial Doppler sonography (fTCD). As for the single attributes - hair-whorl direction, handedness, and language dominance - we reproduced previously published results. However, we found no association between hair-whorl direction and either language dominance or handedness. These results strongly argue against a common genetic basis of handedness or language lateralization with scalp hair-whorl direction. Inspection of hair patterns will not help us to determine language dominance.
Collapse
Affiliation(s)
- Andreas Jansen
- Department of Neurology, University of Münster, Germany.
| | | | | | | | | | | |
Collapse
|
26
|
Lessa Mansur L, Radanovic M, Santos Penha S, Iracema Zanotto de Mendonça L, Cristina Adda C. Language and visuospatial impairment in a case of crossed aphasia. Laterality 2006; 11:525-39. [PMID: 16966241 DOI: 10.1080/13576500600832030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Crossed aphasia in dextrals (CAD) constitutes an interesting model for understanding the lateralisation and interaction of language with other cognitive functions in the brain. The authors present a study of a right-handed patient with Wernicke's aphasia following a right hemisphere cerebrovascular accident, who also had impairment in visuospatial skills. Although the patient presented a remarkable improvement in language symptoms on longitudinal follow-up, the combination of linguistic, visuospatial, and attentional impairments ultimately resulted in a persisting inability to perform complex tasks. The study of mild residual disturbances can improve our understanding of the interaction of language with other cognitive functions, going some way towards explaining the particular features found in CAD.
Collapse
|
27
|
Jansen A, Menke R, Sommer J, Förster AF, Bruchmann S, Hempleman J, Weber B, Knecht S. The assessment of hemispheric lateralization in functional MRI--robustness and reproducibility. Neuroimage 2006; 33:204-17. [PMID: 16904913 DOI: 10.1016/j.neuroimage.2006.06.019] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Revised: 06/08/2006] [Accepted: 06/18/2006] [Indexed: 11/29/2022] Open
Abstract
Various methods have been proposed to calculate a lateralization index (LI) on the basis of functional magnetic resonance imaging (fMRI) data. Most of them are either based on the extent of the activated brain region (i.e., the number of "active" voxels) or the magnitude of the fMRI signal change. The purpose of the present study was to investigate the characteristics of various variants of these approaches and to identify the one that yields the most robust and reproducible results. Robustness was assessed by evaluating the dependence on arbitrary external parameters, reproducibility was assessed by Pearson's correlation coefficient. LIs based on active voxels counts at one single fixed statistical threshold as well as LIs based on unthresholded signal intensity changes (i.e., based on all voxels in a region of interest) yielded neither robust nor reproducible laterality results. Instead, the lateralization of a cognitive function was best described by "thresholded" signal intensity changes where the activity measure was based on signal intensity changes in those voxels in a region of interest that exceeded a predefined activation level. However, not all other approaches should be discarded completely since they have their own specific application fields. First, LIs based on active voxel counts in the form of p-value-dependent lateralization plots (LI=LI(p)) can be used as a straightforward measure to describe hemispheric dominance. Second, LIs based on active voxel counts at variable thresholds (standardized by the total number of active voxels) are a good alternative for big regions of interest since LIs based on signal intensity changes are restricted to small ROIs.
Collapse
Affiliation(s)
- A Jansen
- Department of Neurology, University of Münster, Germany.
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Szaflarski JP, Holland SK, Schmithorst VJ, Byars AW. fMRI study of language lateralization in children and adults. Hum Brain Mapp 2006; 27:202-12. [PMID: 16035047 PMCID: PMC1464420 DOI: 10.1002/hbm.20177] [Citation(s) in RCA: 261] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Language lateralization in the brain is dependent on family history of handedness, personal handedness, pathology, and other factors. The influence of age on language lateralization is not completely understood. Increasing left lateralization of language with age has been observed in children, while the reverse has been noted in healthy young adults. It is not known whether the trend of decreasing language lateralization with age continues in the late decades of life and at what age the inflection in language lateralization trend as a function of age occurs. In this study, we examined the effect of age on language lateralization in 170 healthy right-handed children and adults ages 5-67 using functional MRI (fMRI) and a verb generation task. Our findings indicate that language lateralization to the dominant hemisphere increases between the ages 5 and 20 years, plateaus between 20 and 25 years, and slowly decreases between 25 and 70 years.
Collapse
Affiliation(s)
- Jerzy P Szaflarski
- Department of Neurology, University of Cincinnati Medical Center, Cincinnati, Ohio 45267-0525, USA.
| | | | | | | |
Collapse
|
29
|
Abstract
BACKGROUND The right shift (RS) theory of handedness suggests that poor phonology may occur in the general population as a risk associated with absence of an agent of left cerebral speech, the hypothesised RS + gene. The theory predicts that poor phonology is associated with reduced bias to right-handedness. METHODS A representative cohort of primary school children was assessed on tests of phonology, nonverbal ability, literacy, and handedness. There were three types of analysis; for discrete variables, poor phonology and left hand preference; for continuous variables, phonology factor scores and hand skill; for "cases" of specifically poor phonology. RESULTS Reduced bias to dextrality was found in those with poor phonology for all types of analysis. Trends were similar for both sexes but stronger in males than females. Poor phonology was associated with a raised proportion of left-handed brothers. There was a strong association between poor phonology and poor literacy, but not all those with specifically poor phonology were poor readers or spellers. Among children with poor phonology but not poor for other variables, some 23-31% were left-handed writers. CONCLUSIONS Poor phonological processing is associated with reduced bias to the right hand, consistent with absence of an agent of left hemisphere advantage.
Collapse
Affiliation(s)
- Pamela Smythe
- School of Psychology, University of Leicester, University Road, Leicester LE1 7RH, UK
| | | |
Collapse
|
30
|
Dos Santos Sequeira S, Woerner W, Walter C, Kreuder F, Lueken U, Westerhausen R, Wittling RA, Schweiger E, Wittling W. Handedness, dichotic-listening ear advantage, and gender effects on planum temporale asymmetry—A volumetric investigation using structural magnetic resonance imaging. Neuropsychologia 2006; 44:622-36. [PMID: 16098999 DOI: 10.1016/j.neuropsychologia.2005.06.014] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2004] [Revised: 06/15/2005] [Accepted: 06/23/2005] [Indexed: 11/29/2022]
Abstract
Previous research has often examined whether the asymmetrical structure of the planum temporale (PT) represents an anatomical correlate of lateralized language-processing functions, gathering diverging empirical evidence by comparing PT asymmetry in subjects with differing handedness, gender, or speech lateralization. Apart from other methodological problems, direct comparisons between studies are hampered by insufficient assessment and consideration of all three potential determinants of structural cerebral asymmetry. Based on volumetric assessment of structural Magnetic Resonance Imaging (MRI) scans of 104 healthy subjects, the present study replicated earlier observations of an overall leftward PT asymmetry, which was found to prevail irrespective of handedness, gender, or dichotic-listening ear advantage. However, the mean magnitude of this leftward asymmetry was not determined by either one of these factors in itself, but varied depending on their specific combination. A clear correspondence between structural and functional asymmetry was only observed among right-handed males. In this particular subgroup, more pronounced structural asymmetry was associated with an enlarged PT on the left side, while the enhanced leftward asymmetry of female sinistrals resulted from smaller adjusted volumes of their right PT. The existence of such complex interactions suggests that future research in this area can only be expected to overcome past inconsistencies by adequately considering handedness, gender, and speech lateralization.
Collapse
Affiliation(s)
- Sarah Dos Santos Sequeira
- Center for Neuropsychological Research, University of Trier, Johanniterufer 15, D-54290 Trier, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Jansen A, Flöel A, Menke R, Kanowski M, Knecht S. Dominance for language and spatial processing: limited capacity of a single hemisphere. Neuroreport 2005; 16:1017-21. [PMID: 15931080 DOI: 10.1097/00001756-200506210-00027] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Using functional magnetic resonance imaging during word generation and spatial judgement (Landmark task), we investigated how hemispheric specializations for language and spatial processing interact in healthy individuals. We found individuals with atypical, right-hemispheric dominance for language to have more bilateral activation during spatial judgement than individuals with typical, disjunct hemispheric specialization, that is, left dominance for language and right dominance for spatial tasks. These findings suggest that hemispheric specializations for language and spatial functions interfere to some extent and favour additional recruitment of the opposite hemispheres for spatial functions.
Collapse
Affiliation(s)
- Andreas Jansen
- Department of Neurology, University of Münster, Münster, Germany.
| | | | | | | | | |
Collapse
|
32
|
McManus IC, Martin N, Stubbings GF, Chung EMK, Mitchison HM. Handedness and situs inversus in primary ciliary dyskinesia. Proc Biol Sci 2005; 271:2579-82. [PMID: 15615683 PMCID: PMC1691902 DOI: 10.1098/rspb.2004.2881] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
... The limbs on the right side are stronger. [The] cause may be ... [that] ... motion, and abilities of moving, are somewhat holpen from the liver, which lieth on the right side. (Sir Francis Bacon, Sylva sylvarum (1627).)Fifty per cent of people with primary ciliary dyskinesia (PCD) (also known as immotile cilia syndrome or Siewert-Kartagener syndrome) have situs inversus, which is thought to result from absent nodal ciliary rotation and failure of normal symmetry breaking. In a study of 88 people with PCD, only 15.2% of 46 individuals with situs inversus, and 14.3% of 42 individuals with situs solitus, were left handed. Because cerebral lateralization is therefore still present, the nodal cilia cannot be the primary mechanism responsible for symmetry breaking in the vertebrate body. Intriguingly, one behavioural lateralization, wearing a wrist-watch on the right wrist, did correlate with situs inversus.
Collapse
Affiliation(s)
- I C McManus
- Department of Psychology, University College London, Gower Street, London WC1E 6BT, UK.
| | | | | | | | | |
Collapse
|
33
|
Flöel A, Buyx A, Breitenstein C, Lohmann H, Knecht S. Hemispheric lateralization of spatial attention in right- and left-hemispheric language dominance. Behav Brain Res 2005; 158:269-75. [PMID: 15698893 DOI: 10.1016/j.bbr.2004.09.016] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2004] [Accepted: 09/07/2004] [Indexed: 10/26/2022]
Abstract
Hemispheric lateralization of the neural systems supporting language and spatial attention most commonly dissociate in healthy individuals. However, the reverse pattern with association of language and attention within the right hemispheres has also been observed. We investigated in 75 healthy volunteers (37 right-handed, 38 left-handed) if language and spatial attention may associate not only in individuals with an atypical pattern of language lateralization, but also in subjects showing the standard, i.e. left-hemispheric dominance for language. Hemispheric lateralization of cerebral perfusion was determined with functional transcranial Doppler ultrasonography during a visuospatial attention, and a word generation task. We found that language and visuospatial attention associated within the left hemisphere in five subjects and within the right hemisphere in eight subjects. We conclude that all combinations of cerebral lateralization for language and attention may exist in the healthy brain.
Collapse
Affiliation(s)
- A Flöel
- Human Cortical Physiology Section, National Institute of Neurological Disorders and Stroke, NIH, 10 Center Drive, Building 10, Bethesda, MD 20892-1430, USA.
| | | | | | | | | |
Collapse
|
34
|
Jansen A, Flöel A, Deppe M, van Randenborgh J, Dräger B, Kanowski M, Knecht S. Determining the hemispheric dominance of spatial attention: a comparison between fTCD and fMRI. Hum Brain Mapp 2004; 23:168-80. [PMID: 15449360 PMCID: PMC6871950 DOI: 10.1002/hbm.20055] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human brain mapping allows the systematic assessment of interindividual differences in functional brain anatomy. Functional transcranial Doppler sonography (fTCD) is an imaging tool that allows for fast and mobile assessment of hemispheric lateralization of task-related brain activation. It is ideal to screen large cohorts of subjects. The goal of the present study was to investigate whether fTCD and functional magnetic resonance imaging (fMRI) determine hemispheric lateralization of brain activation related to visuospatial attention concordantly. Used together, fMRI and fTCD may then open up a wide range of potential applications in neuroscience. Fifteen subjects were examined both with fTCD and fMRI while they judged accuracy of line bisections (Landmark task). For fTCD, the maximal mean difference in stimulus-related relative cerebral blood flow velocity changes in the left and right middle cerebral arteries was assessed as the lateralization index LI(fTCD). For fMRI, two approaches were used to determine hemispheric dominance. First, we measured brain activity as the extent of the activated region, i.e., the number of activated voxels above a statistical threshold. Second, we calculated the magnitude of the fMRI signal change between the activation and the control task within a region of interest. Results of fTCD and fMRI were concordant in every single case. Therefore, scanning large cohorts with fTCD for hemispheric dominance during Landmark task will provide results consistent with fMRI. FMRI can then be used for in depth assessment of the specific patterns of activation.
Collapse
Affiliation(s)
- Andreas Jansen
- Department of Neurology, University of Münster, D-4829 Münster, Germany.
| | | | | | | | | | | | | |
Collapse
|
35
|
Bartha L, Mariën P, Poewe W, Benke T. Linguistic and neuropsychological deficits in crossed conduction aphasia. Report of three cases. BRAIN AND LANGUAGE 2004; 88:83-95. [PMID: 14698734 DOI: 10.1016/s0093-934x(03)00281-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
This study describes the linguistic and neuropsychological findings in three right-handed patients with crossed conduction aphasia. Despite the location of the lesion in the right hemisphere, all patients displayed a combination of linguistic deficits typically found in conduction aphasia following analogous damage to the left hemisphere. Associated cognitive deficits varied across the three patients. In addition, all cases showed deficits classically attributed to non-dominant hemisphere damage (visuoperceptual deficits and reduced figural memory). As a result, lesion-behaviour relationships in our study sample indicate both dominant and non-dominant qualities of the right hemisphere.
Collapse
Affiliation(s)
- Lisa Bartha
- Universitaetsklinik fuer Neurologie, Anichstrasse 35, Innsbruck A-6020, Austria.
| | | | | | | |
Collapse
|
36
|
Foundas AL, Corey DM, Angeles V, Bollich AM, Crabtree-Hartman E, Heilman KM. Atypical cerebral laterality in adults with persistent developmental stuttering. Neurology 2003; 61:1378-85. [PMID: 14638959 DOI: 10.1212/01.wnl.0000094320.44334.86] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Two of the most consistent anatomic asymmetries found in the human brain are a larger right than left prefrontal and left than right occipital lobe. Reduced or reversed asymmetries of these regions are considered markers of atypical cerebral laterality, and atypical cerebral laterality has been proposed to increase neural risk for developmental stuttering. OBJECTIVE S: To learn if atypical prefrontal and occipital lobe asymmetries are more common in adults who stutter vs fluent control subjects and to determine whether lobar size or asymmetry patterns are associated with stuttering severity or language abilities. METHODS Adults with persistent developmental stuttering (n = 16) and matched control subjects (n = 16) had language and stuttering assessments. Subjects were also studied with volumetric MRI scans. Total hemisphere, prefrontal, and occipital lobe regions were measured, and volumes were calculated proportionally to hemisphere volume. RESULTS Hemisphere and total brain volumes did not differ between the groups. Control subjects had the expected larger right than left prefrontal and larger left than right occipital lobe volume. In contrast, the adults who stutter did not have these asymmetries. Stuttering severity was not associated with specific anatomic configurations, whereas language-processing deficits in adults who stutter were associated with prefrontal and occipital volume reduction. CONCLUSIONS Developmental stuttering is associated with atypical prefrontal and occipital lobe asymmetries. In addition, deficits in language processing were associated with some anatomic measures in the adults who stutter.
Collapse
Affiliation(s)
- A L Foundas
- Department of Psychiatry and Neurology, Tulane University Health Sciences Center, New Orleans, LA 70112, USA.
| | | | | | | | | | | |
Collapse
|
37
|
Foundas AL, Leonard CM, Hanna-Pladdy B. Variability in the anatomy of the planum temporale and posterior ascending ramus: do right- and left handers differ? BRAIN AND LANGUAGE 2002; 83:403-424. [PMID: 12468396 DOI: 10.1016/s0093-934x(02)00509-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The anatomy of the planum temporale (PT) and posterior ascending ramus (PAR) was studied in vivo in 67 healthy right- and left-handed adults using MRI-based morphometry. The left PT was significantly larger than the right, and there was a weakly significant effect of the right PAR larger than the left. A leftward PT asymmetry was found in 72%, and a rightward PAR asymmetry was found in 64% of the sample. The "typical" configuration of a larger left PT and larger right PAR co-occurred in 56% of the subjects studied, which was only slightly more often than predicted by chance. Eight of 67 subjects had "reversed" PT and PAR asymmetries, with consistent left and mixed handers over-represented in this group. Right PAR size was the only variable that predicted writing hand, and left PT size was the only measure that differed by sex. The left PT was expanded relative to the left PAR in 93% of the sample, suggesting that this configuration may be developmentally regulated and may be a critical substrate for the development of language. These findings demonstrate that important relationships exist between hand preference, and the anatomy of posterior cortical language areas.
Collapse
Affiliation(s)
- Anne L Foundas
- Department of Psychiatry and Neurology, Tulane University Health Science Center, Veterans Affairs Medical Center, 1430 Tulane Avenue, New Orleans, LA 70115, USA.
| | | | | |
Collapse
|
38
|
Noroozian M, Lotfi J, Gassemzadeh H, Emami H, Mehrabi Y. Academic achievement and learning abilities in left-handers: guilt or gift? Cortex 2002; 38:779-85. [PMID: 12507046 DOI: 10.1016/s0010-9452(08)70044-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The main purpose of this cross-sectional study was to compare the acceptance rate (AR) of left-handers (LHs) with that of right-handers (RHs) in the college entrance examination (CEE) for the national universities in Iran. During 5 successive years, fifty thousand participants in this exam were randomly sampled. We evaluated the relationships between AR and hand preference, sex, college admission (CA), entrance exam score (EES) and study areas: Mathematics, Natural Sciences, Humanities and Art. The acceptance rate of the LHs over the entire study period was significantly higher than that of the RHs (27.3% versus 24.3%, p < 0.0001). The mean score attained on examination by LHs was significantly higher than that of RHs in all study areas (p < 0.002). The acceptance rate of LHs in all study areas was higher but the difference reached statistical significance in the Art area only (p < 0.01). It is concluded that left-handers may be regarded as a heterogeneous large group consisting of different subgroups. Those who are able to compete for the college entrance examination score are even more successful than right-handers in terms of average EES and the rate of CA.
Collapse
Affiliation(s)
- Maryam Noroozian
- Neurology and Electroencephalography Unit, Department of Psychiatry, Tehran University of Medical Sciences, Faculty of Medicine, Roozbeh Hospital, Iran.
| | | | | | | | | |
Collapse
|
39
|
Abstract
The purpose of this study was to investigate whether and how handedness is related to the processes of cerebral lateralization and cognitive performance in children with congenital insult. Fifty-six children (31 males and 25 females) with congenital hemiparesis and 14 control subjects were investigated. Of these children, 32 had a left hemisphere lesion, and 24 children had a right hemisphere lesion. There were 30 right-handed, 23 left-handed, and three ambidextrous children in the study group. The neuropsychologic assessment was performed using the NEPSY (a developmental neuropsychological assessment of child development) test battery. We found that 41% of the hemiparetic children and 72% of the children with a left hemisphere lesion were left-handed. In children contralateral to lesion handedness (no evidence of interhemispheric transfer of functions), we found diffuse cognitive deficits with impaired language abilities and poor visuomotor and narrative memory processing. In contrast, children with ipsilateral to brain lesion handedness (interhemispheric transfer of functions) demonstrated minimal or moderate side-specific cognitive dysfunction. Right-handed children with a right hemisphere lesion had attention, spatial, and short-term memory problems; left-handed children with a left hemisphere lesion had receptive language and visuomotor difficulties. Handedness combined with neuropsychologic assessment is a reliable indicator of the processes of cerebral reorganization after early brain insult.
Collapse
Affiliation(s)
- Anneli Kolk
- Department of Paediatrics, University of Tartu, Unit of Neurology, Children's Clinic of Tartu University Clinics, Tartu, Estonia
| | | |
Collapse
|
40
|
Lipsanen T, Lauerma H, Peltola P, Kallio S. Associations among dissociative experiences, handedness, and demographic variables in a nonclinical population. J Nerv Ment Dis 2000; 188:422-7. [PMID: 10919700 DOI: 10.1097/00005053-200007000-00005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Handedness is considered an indirect marker for bilateral language capacity in the brain. The Edinburgh Inventory for Handedness and the Dissociative Experiences Scale (DES) were administered to 297 nonclinical volunteers. Female sex, young age, and non-right handedness accounted for 24% of the total variance on the DES, including both pathological and nonpathological dissociative experiences. This is consistent with the hypothesis that cerebral lateralization indicating handedness is a predisposing factor for dissociative episodes especially in female subjects.
Collapse
Affiliation(s)
- T Lipsanen
- Department of Psychiatry, Turku University Central Hospital, Finland
| | | | | | | |
Collapse
|
41
|
Amunts K, Schleicher A, Bürgel U, Mohlberg H, Uylings HB, Zilles K. Broca's region revisited: cytoarchitecture and intersubject variability. J Comp Neurol 1999; 412:319-41. [PMID: 10441759 DOI: 10.1002/(sici)1096-9861(19990920)412:2<319::aid-cne10>3.0.co;2-7] [Citation(s) in RCA: 909] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The sizes of Brodmann's areas 44 and 45 (Broca's speech region) and their extent in relation to macroscopic landmarks and surrounding areas differ considerably among the available cytoarchitectonic maps. Such variability may be due to intersubject differences in anatomy, observer-dependent discrepancies in cytoarchitectonic mapping, or both. Because a reliable definition of cytoarchitectonic borders is important for interpreting functional imaging data, we mapped areas 44 and 45 by means of an observer-independent technique. In 10 human brains, the laminar distributions of cell densities were measured vertical to the cortical surface in serial coronal sections stained for perikarya. Thousands of density profiles were obtained. Cytoarchitectonic borders were defined as statistically significant changes in laminar patterns. The analysis of the three-dimensional reconstructed brains and the two areas showed that cytoarchitectonic borders did not consistently coincide with sulcal contours. Therefore, macroscopic features are not reliable landmarks of cytoarchitectonic borders. Intersubject variability in the cytoarchitecture of areas 44 and 45 was significantly greater than cytoarchitectonic differences between these areas in individual brains. Although the volumes of area 44 differed across subjects by up to a factor of 10, area 44 but not area 45 was left-over-right asymmetrical in all brains. All five male but only three of five female brains had significantly higher cell densities on the left than on the right side. Such hemispheric and gender differences were not detected in area 45. These morphologic asymmetries of area 44 provide a putative correlate of the functional lateralization of speech production.
Collapse
Affiliation(s)
- K Amunts
- C. and O. Vogt Institute for Brain Research, Heinrich Heine University, D-40001 Düsseldorf, Germany.
| | | | | | | | | | | |
Collapse
|
42
|
Abstract
The right shift (RS) theory of handedness and cerebral dominance (Annett, 1972, 1985) suggested that individual differences for patterns of cerebral dominance may be associated with different types of risk to cognitive functions. The higher prevalence of dextrality than sinistrality in humans depends on a single gene (RS+) which facilitates left hemisphere specialisation for speech but at the expense of some right hemisphere function (Annett, 1992b; Kilshaw and Annett, 1983). RS-- genotypes have random asymmetries for hand and brain while RS++ genotypes have strong right shift. Three samples of undergraduates were given tests of phonological processing and of real word homophone discrimination. As predicted, phonology was poor in comparison with homophone discrimination toward the left of the laterality continuum while the reverse was true to the right of the continuum. When groups with specific difficulty for each type of test in comparison with the other were distinguished, those with poor phonology were less dextral and those with poor homophone discrimination were more dextral for hand preference than the rest of the sample. Siblings differed for handedness also, consistent with the argument for a genetic influence.
Collapse
Affiliation(s)
- M Annett
- Department of Psychology, University of Leicester, UK.
| |
Collapse
|
43
|
Abstract
Crow (1995a) has argued that schizophrenia is caused by a gene associated with the evolution of human language and cerebral specialisation. This paper suggests a mechanism for Crow's theory which requires only one new assumption for the right shift genetic model of handedness and cerebral dominance (Annett, 1978). The proposal is that the RS+ allele, whose normal function is to induce the left hemisphere to serve speech by impairing speech-related cortex in the right hemisphere, tends to lose its directional coding. It becomes agnosic (RS+ a) for right versus left and impairs the left or right hemisphere at random. Schizophrenia is likely to develop when the RS+ a gene is paired with a normal RS+ gene but only in the 50% of cases where both hemispheres are affected. In the 50% where RS+ a affects the right hemisphere, development is normal as in the RS+ RS+ genotype. The risks for schizophrenia in monozygotic and dizygotic twins and other relatives are as expected for 50% expression of a Mendelian gene which is paired with a particular allele, but not alternative alleles at the same locus. The frequency of homozygotes for the agnosic gene is about 4 in 10,000, the rate observed for autism. A random pattern of double hemisphere deficits would give scope for a range of developmental strengths and weaknesses as observed within the spectrum of autistic disorders. Tests of the model require brain-imaging studies sensitive to individual differences in hemisphere lateralisation and a search for a genetic locus with human and nonhuman primate alleles, together with a mutant of the human form with a frequency of about 2%.
Collapse
Affiliation(s)
- M Annett
- Department of Psychiatry, University of Leicester, UK
| |
Collapse
|