Recovery from aphasia: a longitudinal study on language recovery, lateralization patterns, and attentional resources.

Despite the large body of evidence on the neural basis of the recovery from aphasia, the role of either cerebral hemisphere remains controversial. This paper reports the results of a longitudinal single-case study on the patterns of lateralization for lexical semantic processing during the recovery from aphasia. The experimental protocol included a lateralized lexical decision task (LDT), an attentional task and a language test. There was no presentation site effect on the LDT, and the performance was jointly influences by attentional and language factors. These findings suggest that the recovery of lexical semantic processing may be sustained by both cerebral hemispheres, and highlights the importance of experimental protocols that allow examining both language and attentional factors modulating factors modulating the recovery from aphasia.

Long-term effect of prefrontal lobotomy on verbal fluency in patients with schizophrenia.

OBJECTIVE: This study investigated the long-term effects of bilateral prefrontal leukotomy on lexical abilities in schizophrenia subjects. METHOD: we compared performances of leukotomized (LSP), non-leukotomized schizophrenia patients (NLSP) and normal controls, using a test of verbal fluency. Multiple case and triple comparison design were implemented. i.e., the performance of each LSP was compared to that of NLSP and that of a normal control. The sample consisted of four LSP, four NLSP, and four normal subjects. Subjects were matched in sex, age, handedness, and schooling. In Addition, schizophrenia groups were matched in diagnosis and years of hospitalization. Quantitative and qualitative analyses of generated words and errors produced by subjects were carried out. RESULTS: A deficiency in both groups of schizophrenia was observed, although a better performance in LSP patients was detected. CONCLUSION: Intact Lexical ability in LSP indicates its poor relation to the frontal lobe.

Neural correlates of lexical and sublexical processes in reading.

The purpose of the present study was to compare the brain regions and systems that subserve lexical and sublexical processes in reading. In order to do so, three types of tasks were used: (i). silent reading of very high frequency regular words (lexical task); (ii). silent reading of nonwords (sublexical task); and, (iii). silent reading of very low frequency regular words (sublexical task). All three conditions were contrasted with a visual/phonological baseline condition. The lexical condition engaged primarily an area at the border of the left angular and supramarginal gyri. Activation found in this region suggests that this area may be involved in mapping orthographic-to-phonological whole word representations. Both sublexical conditions elicited significantly greater activation in the left inferior prefrontal gyrus. This region is thought to be associated with sublexical processes in reading such as grapheme-to-phoneme conversion, phoneme assembly and underlying verbal working memory processes. Activation in the left IFG was also associated with left superior and middle temporal activation. These areas are thought to be functionally correlated with the left IFG and to contribute to a phonologically based form of reading. The results as a whole demonstrate that lexical and sublexical processes in reading activate different regions within a complex network of brain structures.

Semantic category differences in cross-form priming.

Findings of category-specific impairments have suggested that human semantic memory may be organized around a living/nonliving dichotomy. In order to assess implicit memory performance for living and nonliving concepts, one group of neurologically intact individuals participated in a cross-form conceptual priming paradigm. In Block 1, pictures primed words while in Block 2 words were used to prime pictures. Across all phases of the experiment, subjects decided whether items represented something which was living or nonliving, and response times were recorded. Results revealed greater priming for living concepts across both blocks. Greater priming for living concepts may have occurred because of increased or prolonged conceptual activation of these concepts. Results are discussed in the context of theoretical accounts of the category-specific impairments observed in brain-damaged populations.

Optokinetic stimulation and the egocentred midsagittal plane: an fMRI study.

Animal studies and observations of neglect patients suggest that the posterior parietal cortex is part of a system that codes ego-centred space. Few studies show the existence of areas involved in the representation of egocentred space in healthy humans. We investigated with fMRI and a conjunction protocol, the overlap of activity between optokinetic stimulation and a task of midline computation. Results showed that the right posterior parietal and frontal cortices were involved in both tasks (p < 0.0001). The evidence presented in this study provides the neuroanatomical substrate involved in the recovery of neglect during vestibular stimulation. This last point is of clinical interest for the rehabilitation of hemineglect.

Areas of brain activation in males and females during viewing of erotic film excerpts.

Various lines of evidence indicate that men generally experience greater sexual arousal (SA) to erotic stimuli than women. Yet, little is known regarding the neurobiological processes underlying such a gender difference. To investigate this issue, functional magnetic resonance imaging was used to compare the neural correlates of SA in 20 male and 20 female subjects. Brain activity was measured while male and female subjects were viewing erotic film excerpts. Results showed that the level of perceived SA was significantly higher in male than in female subjects. When compared to viewing emotionally neutral film excerpts, viewing erotic film excerpts was associated, for both genders, with bilateral blood oxygen level dependent (BOLD) signal increases in the anterior cingulate, medial prefrontal, orbitofrontal, insular, and occipitotemporal cortices, as well as in the amygdala and the ventral striatum. Only for the group of male subjects was there evidence of a significant activation of the thalamus and hypothalamus, a sexually dimorphic area of the brain known to play a pivotal role in physiological arousal and sexual behavior. When directly compared between genders, hypothalamic activation was found to be significantly greater in male subjects. Furthermore, for male subjects only, the magnitude of hypothalamic activation was positively correlated with reported levels of SA. These findings reveal the existence of similarities and dissimilarities in the way the brain of both genders responds to erotic stimuli. They further suggest that the greater SA generally experienced by men, when viewing erotica, may be related to the functional gender difference found here with respect to the hypothalamus.

Anartria pura: estudo de dois casos / Pure anartria: study of two cases

O marco do nascimento da neurolingüística é considerado a publicação do livro A síndrome de Desintegração Fonética, em 1939, que teve como autores: um neurologista, um psicólogo e uma lingüista. Dez anos mais tarde foi publicado, pela mesma equipe de pesquisadores franceses, o distúrbio de fala do paciente portador de anartria pura. No presente artigo, situaremos as polêmicas históricas a respeito de um distúrbio seletivo de fala de origem telencefálica, apresentaremos o primeiro caso descrito, acompanhado da descrição anátomo-patológica do cérebro que estivera guardado em formol por 20 anos e, realizada por um de nós (ARL), e por fim, apresentaremos um caso brasileiro, cujas imagens tomográficas de seu cérebro e espectográficas de sua fala e voz confirmam o trabalho pioneiro de Alajouanine, Pichot e Durant(AU)

Anartria pura: estudo de dois casos / Pure anartria: study of two cases

O marco do nascimento da neurolingüística é considerado a publicação do livro A síndrome de Desintegração Fonética, em 1939, que teve como autores: um neurologista, um psicólogo e uma lingüista. Dez anos mais tarde foi publicado, pela mesma equipe de pesquisadores franceses, o distúrbio de fala do paciente portador de anartria pura. No presente artigo, situaremos as polêmicas históricas a respeito de um distúrbio seletivo de fala de origem telencefálica, apresentaremos o primeiro caso descrito, acompanhado da descrição anátomo-patológica do cérebro que estivera guardado em formol por 20 anos e, realizada por um de nós (ARL), e por fim, apresentaremos um caso brasileiro, cujas imagens tomográficas de seu cérebro e espectográficas de sua fala e voz confirmam o trabalho pioneiro de Alajouanine, Pichot e Durant