In 1861 Paul Broca discovered that, in most individuals, the left hemisphere of the brain is dominant for language. Taking language as an example, the first part of this book explains the normal development of bodily asymmetry and lateralization, its association with hand preference, genetic aspects, geographical differences and the influence of gender. The coverage then moves on to review the association between language lateralization and psychosis, describing findings in patients with schizophrenia to suggest the dominant hemisphere may fail to completely inhibit the language areas in the non-dominant half. The language allowed to 'release' from the right hemisphere can lead to psychotic symptoms including auditory verbal hallucinations and formal thought disorder. This book should be read by psychiatrists, neurologists and neuroscientists working in the field of psychosis and other brain scientists interested in laterality.
Iris E. C. Sommer is a Psychiatrist and Researcher at the Neuroscience Department, University Medical Center Utrecht, The Netherlands. Rene S. Kahn is Professor of Psychiatry and Chairman of the Neuroscience Department, University Medical Center Utrecht, The Netherlands.
List of contributors; Preface; Part I. Asymmetry, Handedness and Language Lateralization: 1. Molecular mechanisms establishing consistent left-right asymmetry during vertebrate embryogenesis Sherry Aw and Michael Levin; 2. Cerebral lateralization in animal species Onur Gunturkun; 3. The history and geography of human handedness I. C. McManus; 4. The association between hand preference and language lateralization Bianca Stubbe-Drager and Stefan Knecht; 5. The genetic basis of lateralization Marian Annett; 6. Language lateralization and handedness in twins; an argument against a genetic basis? Iris E. C. Sommer and Rene S. Kahn; 7. Sex differences in handedness and language lateralization Iris E. C. Sommer and Rene S. Kahn; Part II. Language Lateralization and Psychosis: 8. Hand-preference and population schizotypy Metten Somers, Iris E. C. Sommer and Rene S. Kahn; 9. Functional imaging studies on language lateralization in schizophrenia patients Annick Razafimandimby, Olivier Maiza and Sonia Dollfus; 10. The role of the right hemisphere for language in schizophrenia Alexander Rapp; 11. Auditory verbal hallucinations and language lateralization Kelly Diederen and Iris E. C. Sommer; 12. Language lateralization in patients with Formal Thought Disorder Carin Whitney and Tilo Kircher; 13. LRRTM1: a maternally suppressed genetic effect on handedness and schizophrenia Clyde Francks.