Discovery and evaluation of single nucleotide polymorphisms (SNPs) for Haliotis midae: a targeted EST approach.

In this study, we describe the first set of SNP markers for the South African abalone, Haliotis midae. A cDNA library was constructed from which ESTs were selected for the screening of SNPs. The observed frequency of SNPs in this species was estimated at one every 185 bp. When characterized in wild-caught abalone, the minor allele frequencies and F(ST) estimates for every SNP indicated that these markers may potentially be useful for population analysis, parentage assignment and linkage mapping in Haliotis midae. No linkage disequilibrium was observed between SNPs originating from different EST sequences. These SNPs, together with additional SNPs currently being developed, will provide a useful complementary set of markers to the currently available genetic markers in abalone.

Pierre Jean Georges Cabanis (1757-1808): an early nineteenth century source for the concept of nervous energy in European behavioral neurosciences.

The nineteenth century witnessed many advances in neuroscientific concepts. Among the notable are Charles Bell's (1774-1842) and François Magendie's (1783-1855) identification of sensory and motor pathways, Thomas Henry Huxley's (1825-1895) elaboration of evolutionary theory in the context of comparative neuroanatomy, and Emile Du Bois-Reymond's (1818-1896) and Hermann von Helmholtz's (1821-1894) work in experimental neurophysiology and on the concept of nervous energy. In Germany, the idea that the nervous system consisted of two elements, one that generated nervous energy and another that conducted it throughout the body, had wide currency in mid-nineteenth century. In France, Pierre Jean Georges Cabanis (1757-1808), physician, philosopher, and one of the founders of modern psychophysiology, argued that the brain is the part of the body in which electricity is stored. In his Rapports du Physique et du Moral de l'Homme, published between 1796 and 1802 (translated into German under the title Verhältnis der Seele zum Körper (1808)), Cabanis proposed new ideas on brain function, on the brain's own sensibility, on the concept of will, and on the chemical basis of nervous activity. In the Rapports Cabanis proposed a theory of how brain and nerves relate to thought and behavior. Foreshadowing later developments in neuropsychology, he suggested that different parts of the nervous system have separate functions. Despite the fact that Cabanis had many interesting ideas about brain function, he has been largely ignored by historians of neuroscience; e. g., he is mentioned briefly in Clark and Jacyna (1989), in only two footnotes in Neuburger (1897/1981), and not at all in Finger (1994). Cabanis's far-reaching theory of how the brain works helped shape understanding of the general notion of nervous energy in nineteenth-century European neuroscience.

Brain-injured persons in an altered state of consciousness: measures and intervention strategies.

We evaluated the states of consciousness of seven persons who had sustained a severe head injury, and describe the behavioural manifestations associated with four treatment strategies. The subjects were between the ages of 19 and 55 and were recruited from both acute and long-term care facilities; all were in an altered state of consciousness. The severity of the injury was measured by time in coma, the scores on the Glasgow Coma Scale [1] and the Coma Near Coma Scale [2]. Structured interventions consisted of visual, auditory, olfactory, gustatory and tactile stimulation; behaviour was measured using the Disability Rating Scale [3, 4] and a portion of the Levels of Cognitive Functioning Scale [5]. Sensory-motor indications were recorded using a questionnaire developed by Freeman [6] and a quality-of-life instrument, developed for use with individuals having multiple disabilities [7], was adapted for the purpose of this study. Our results suggest that the use of structured interventions in the first 24 months following severe head injury is associated with a trend towards improved auditory and visual skills performance, manual performance, swallowing and language. Whereas initially no subject had any form of verbalization, by the final evaluation five subjects had some form of communication, either verbal or non-verbal.

Theodor Meynert's contribution to classical 19th century aphasia studies.

Carl Wernicke (1848-1905) is traditionally considered the first to have described the features of, and the brain pathology underlying, impaired auditory comprehension and related symptoms. Although Wernicke (1874) clearly and repeatedly indicates his indebtedness to Theodor von Meynert (1833-1892), this is usually understood as an acknowledgment that Meynert taught Wernicke neuroanatomy (Eggert, 1977); Wernicke's own words in part support this interpretation. A more sophisticated historical analysis notes that, prior to Wernicke, both Johann Schmidt in 1871 and Charlton Bastian in 1869 had described the concept of receptive aphasia, but neither had supported their analyses with autopsy evidence as did Wernicke, thus not dislodging Wernicke's claim of priority. However, a virtually unknown work by Theodor von Meynert, published in 1866, has recently been rediscovered by us ["Ein Fall von Sprachstörung, anatomisch begründet." Medizinische Jahrbücher. XII Band der Zeitschrift der K. K. Gesellleschaft der Arzte in Wien, 22. Jahr. Pp. 152-189]. In this paper Meynert analyzes the anatomical basis for localizing the comprehension of language in the superior temporal gyrus, he argues that lesions in this area should (by analogy to Broca's earlier observations on language expression) cause impairments in language comprehension, and he presents a case of receptive aphasia with autopsy evidence of destruction of the superior temporal gyrus in the left hemisphere. The patient's aphasia was classic; impaired auditory comprehension, and fluent speech with paraphasias. It is clear that Meynert should be given historical credit for his work.

An empirical test of two opposing theoretical models of prefrontal function.

The purpose of this study was to compare the validity of two models which contrast with each other in the manner in which they integrate neuropsychological tests into distinct prefrontal constructs. The first prefrontal model consists of five distinct functional constructs drawn from human clinical neuropsychology. The second model, elaborated by Goldman-Rakic, is based primarily on monkey research and postulates a basic prefrontal function, "on-line representational memory," which guides behavior in the absence of, or despite discriminative environmental stimuli. In the latter model, distinct prefrontal functional constructs are primarily defined in terms of various types of representational memory involved in specific tasks. Eleven "prefrontal" measures were obtained from 259 normal adults, stratified for age, education, and sex. Confirmatory factor analyses revealed that the Goldman-Rakic model "fit" the data better than the model derived from human clinical neuropsychology, while several constructs commonly used in human neuropsychology were refuted. It was concluded that new research on brain-damaged humans with a view to understanding prefrontal function might benefit from using the Goldman-Rakic model as a starting point.

Effects of right and left hemisphere cerebrovascular lesions on discrimination of prosodic and semantic aspects of affect in sentences.

Ten nonaphasic left cerebrovascular accident (CVA) patients, 12 right CVA patients, and 16 normals were matched for age, education, lesion sizes, and postonset intervals; all were right handed. One task consisted of 36 sentences connoting one of six primary emotions (joy, sadness, fear, surprise, disgust, anger) presented binaurally with a neutral emotional tone. Subjects were required to point to the appropriate emotion name on a vertically arranged list. A second task consisted of the same 36 sentences voiced emotionally by humming with a closed mouth, presented binaurally, and requiring the same response as for the preceding task. A third task consisted of 18 of the sentences spoken with concordant emotional tone and the remaining 18 sentences spoken with discordant emotional tone, presented binaurally and requiring pointing to the word "SAME" or "DIFFERENT" arrayed vertically. The right hemisphere (RH) patients were significantly impaired, relative to the left hemisphere (LH) patients and normals, on the pure prosody task (2) and on the emotional concordance task (3), the latter effect being significant only for mismatch categorization. The LH patients performed (nonsignificantly) less well than the RH patients and normals on the verbal contextual task (1). Performances on the three tasks were not significantly correlated in the patient groups. It was concluded that the RH probably dominates for phonetic discrimination of vowel trains (fundamental frequency and/or single vowel or multivowel contour) and that the RH probably dominates for certain forms of selective attention in the verbal domain perhaps involving simultaneous mismatch treatment of ongoing sentence-level, distracting, complementary, verbal processes. Comparison of similar right and left, cortical (frontoparietal), and subcortical (capsule and basal ganglia) lesions suggested, but did not prove, that the RH pure prosody impairment is cortical whereas the RH tonal-semantic mismatch categorization impairment involves subcortical as well as cortical contributions.

Acalculia: an historical review of localization.

This article reviews the brain localization of calculation disorders (acalculia) beginning with Gall's claim in the early 19th century for a "center" of calculation. A renewed interest in the subject arose around the time of Henschen during the first quarter of the 20th century. A summary of the cases of acalculia since Henschen leads to the conclusion that regardless of the functional modular nature of calculation ability, there is neither a localized region nor a specific hemisphere uniquely underlying the disorder.

Cognitive disturbances in Parkinson's disease.

To test the hypothesis that the cognitive impairments that accompany Parkinson's disease (PD) arise from frontal lobe dysfunction, patients with idiopathic PD and controls were tested on a neuropsychological battery that included measures of anterograde memory, visuospatial perception, and naming, as well as several tests that are known to be sensitive to lesions of the frontal lobes. PD patients of normal mental status as measured by the Mini-Mental State Examination performed normally on the naming, line orientation, and verbal recognition memory tests but exhibited deficits on verbal recall. On tests of frontal lobe function, these patients showed mild deficits on a category fluency task and on the Wisconsin Card Sorting Test. However, their errors on the latter were not typical of patients with frontal lesions, and they performed normally on a letter fluency task and exhibited normal release from proactive interference. Patients of lower than normal mental status performed poorly on nearly all of the cognitive tasks including confrontational naming, line orientation, and recognition memory, suggesting that their cerebral dysfunction extended beyond subcortical-frontal circuits. The present study supports the usefulness of the Mini-Mental State Examination for cognitive screening of PD patients, but does not support the hypothesis that the cognitive impairments in PD arise principally from disruption of frontal lobe functioning.

Lexical retrieval in left and right brain lesioned children.

Performance on two measures of lexical retrieval for 19 left and 13 right brain lesioned children was compared to that of control subjects matched by age, sex, race, and social class. On the Word-Finding Test, left lesioned subjects were significantly slower in response time than left controls when given semantic and visual cues and made more errors when given rhyming cues. On the Rapid Automatized Naming Test, left lesioned subjects were significantly slower than left controls in naming all semantic categories, including colors, numbers, objects, and letters. In contrast, right lesioned subjects responded as quickly as or more quickly than did right controls in all access conditions and in naming semantic categories yet tended to produce more errors than their controls, suggesting a speed-accuracy tradeoff. Children sustaining left brain lesions before 1 year of age appeared to be as impaired as those whose lesions occurred after 1 year of age. Diverse lesion sites within the left hemisphere were associated with increased lexical retrieval latencies.

Spoken syntax in children with acquired unilateral hemisphere lesions.

The spoken syntax of eight left hemisphere lesioned and eight right hemisphere lesioned children were compared to matched controls. The children's lesions were acquired between 0.08 and 6.17 years of age (mean = 1.33 years), and at the time of testing they were between 1.67 and 8.15 years of age (mean = 4.19). Based on analyses of spontaneous language samples, left hemisphere lesioned subjects performed more poorly than did their controls on most measures of simple and complex sentence structure. In contrast right lesioned subjects performed similarly to their controls on these measures, except for a tendency to make more errors in simple sentence structures. These findings provide further evidence that the left and right hemispheres are not comparable in supporting syntactic abilities.

Verbal and cognitive sequelae following unilateral lesions acquired in early childhood.

Eight left-hemisphere lesioned children and eight right-hemisphere lesioned children between 18 months and 8 years of age were compared to control subjects on a battery of intelligence and language measures. Both left- and right-lesioned subjects had lower IQ scores than their controls, yet most functioned within the normal range or higher. Lexical comprehension and production were depressed in both subject groups and appeared to be depressed to a greater degree in right-lesioned subjects than in those with left lesions. In contrast, syntactic production in left-lesioned subjects was markedly deficient in comparison to controls as well as right-lesioned subjects. Although both subjects and controls included children with articulation errors, the number of misarticulating children and misarticulated sounds was greatest in the left-lesioned group. Finally, fluency disorders were observed in both right- and left-lesioned subjects but were not observed in controls. The study provides further evidence that the right and left hemispheres are not equipotential for language and that left-hemisphere lesions acquired early in childhood impair syntactic development to a greater degree than do right-hemisphere lesions.

Agrammatism on inflectional bound morphemes: a case study of a Hindi-speaking aphasic patient.

In this report, we discuss a Hindi agrammatic patient who exhibited greater difficulty with the production of inflectional bound morphemes than with function words. The patient retained the metalinguistic judgement to differentiate function words with semantic content, such as postpositions which mark case functions in Hindi. His impaired ability to produce bound inflections also affected his retrieval of verbs; this failure to retrieve verbs was not due to anomia. Further neurolinguistic analyses of synthetic languages would seem likely to extend our understanding of syntactic processes.

Acquired capsular/striatal aphasia in childhood.

We studied a case of language loss caused by an acquired vascular lesion in the putamen, anterior limb of the internal capsule, and lateral aspect of the head of the caudate nucleus in a 7-year-old right-handed girl. Acute right-sided hemiplegia, mutism, oral apraxia, and disturbance in language comprehension but no dysarthria were present. During recovery, a nonfluent aphasia with anomia was evident. After six months, only mild hemiparesis and minor spelling difficulties persisted. We compared this patient with an 11-year-old right-handed girl with right-sided hemiparesis and dysarthria but no language loss following a lesion in the globus pallidus, a portion of the posterior limb of the internal capsule, and the body of the caudate. The presence of a language disturbance in the first but not the second patient was attributed to the difference in lesion location. The symptoms and lesions were similar to those in recent reports of adult patients. To our knowledge, this is the first report of these findings in a child with a left-hemisphere lesion.

Language function and dysfunction among Chinese- and English-speaking polyglots: cortical stimulation, Wada testing, and clinical studies.

Language functions in a group of Chinese- and English-speaking polyglots living in a multiracial society have been investigated by several methods: the effects of cortical stimulation on object-naming and reading tasks in patients who required awake craniotomy, lateralization of cerebral dominance for speech by the Wada Test, and the pattern of language loss and recovery following stroke. The data indicate that these polyglots were all left hemisphere dominant for the languages tested: no consistent evidence for increased participation by the right hemisphere for language functions was found. The cortical stimulation experiments provided data most compatible with the "differential localization" model of cerebral localization in bilingualism. The variable which most influenced performance in all of these investigations was which language was used primarily for speaking as well as reading and writing at the time of the study.

Alliteration and assonance in neologistic jargon aphasia.

This paper discusses certain aspects of the speech patterns of neologistic jargon aphasic patients, whose syndrome is one form of a more general classification referred to as Wernicke's or cortical sensory aphasia. The classical lesion site is in the posterior superior temporal convolution of the dominant hemisphere. Patients with such lesions typically have difficulties in the comprehension of auditory linguistic stimuli and their speech is often marked with neologistic jargon. A neologism is a phonological form produced by the patient for which one cannot recover with any reasonable degree of certainty some single item in the patient's vocabulary as it presumably existed before the onset of the disease. Specific analysis is focused on those stretches of speech which exhibit perseveration to the point where there is an excessive amount of alliteration and assonance. The data is described in terms of segments, syllables and sequences of syllables and related to both a mechanism underlying the production of this sort of speech and to the more general problems of neologisms in jargon aphasia.