Influence of age on the dynamics of fMRI activations during a semantic fluency task.

PURPOSE: Age-related fMRI changes have not been extensively studied for language, whereas important adaptive mechanisms have been seen in other cognitive fields. This study examined age-related changes in fMRI activation during language tasks and, in particular, their dynamic course. PATIENTS AND METHODS: fMRI was performed on 22 young and 21 old healthy right-handed subjects during a silent category word-generation task. Activation and dynamics of BOLD signals were studied separately during the first and second portions of each 30-s block. RESULTS: Activation of the left frontal lobe was initially similar in young and old participants; however, it decreased after 30 s in the old participants. On the other hand, additional areas were initially involved only in old subjects and especially in the default mode network. CONCLUSION: This study showed age-related differences in the dynamics of fMRI activation during a silent word-generation task, suggesting a different pattern of language function with aging.

Generalization of the effects of phonological training for anomia using structural equation modelling: a multiple single-case study.

Structural Equation Modelling analysis of three longitudinal er-fMRI sessions was used to test the impact of phonological training and of the generalization process on the pattern of brain connectivity during overt picture naming in two chronic anomic patients. Phonological training yielded a positive effect on the trained material. Six months after the training, a generalization of the positive impact on the untrained items was also observed. Connectivity analysis showed that training and generalization effects shared paralleled cortical patterns of functional integration. These findings may represent the neurophysiological correlate of the training-induced cognitive strategies for the compensation of anomia.

[Communication, language and the brain: from past anterior to near future]. / Communication, langage et cerveau : du passé antérieur au futur proche.

The goal of this article is to share some reflection on the astonishing evolution of the ideas in communication neuroscience and neurolinguistics over the last 30 years, since the founding of the société de neuropsychologie de langue française. in particular, a number of conceptual and methodological advancements have characterized this period, many of which have been lead or heavily contributed by french-speaking research groups in that field. among the advances discussed, are (a) the widening to discourse and pragmatic components of the concept of language, as well as the theoretical and clinical implication of this conceptual extension, (b) the unique contribution of anatomical and functional neuroimaging, (c) the massive impact of the cognitive revolution on theoretical frameworks of language components, and its influence on therapy, (d) the disappearance and the re-appearance of the brain in the main stream research on language over this period, (e) the new perspectives offered though attention put on social aspects of language and the social participation of the individual with language disorders, (f) the emergence of a genuine science of aphasia rehabilitation, and (g) the rediscovery of inter-individual characteristics both genetically- and environmentally- determined. The authors then risk themselves in trying to envision what could characterize the evolution in the field for the next 30 years. Though perilous, this speculative exercise allowed to pinpoint to a number of anticipated advancements including (a) a probable reconciliation between cognitive and connectionist models to the benefit of both visions, (b) an increased contribution of social and emotional neurosciences, (c) some inescapable technological advancements, including light portable neuroimaging devices which will allow to study the neurobiological bases of communication in natural contexts, (d) the integration between communication and aging in cognitive neuroscience and (e) the development of new research fields at some unexpected cross-roads (e.g., physical activity and communication ?) as well as the description of new types of aphasia (e.g., towards a chat aphasia !). Taken together, the advancements made over the 30 last years, and the perspective of future development, confirms the premier role of cognitive neuroscience of language and neurolinguistics in setting the pace through innovative approaches that allow unveiling the mysteries of the mutual relationships between brain and cognition.

[The impact of lesions in the right hemisphere on linguistic skills: theoretical and clinical perspectives]. / Impacto de las lesiones del hemisferio derecho sobre las habilidades lingüísticas: perspectivas teórica y clínica.

INTRODUCTION: A lesion of the right hemisphere of right-handers can result in verbal communication impairments. The recent development of theoretical frameworks with regard to discourse and pragmatic abilities, among others, now allows us to recognize and describe these impairments. AIM: To offer an overview of the verbal communication deficits that can be found in right-hemisphere-damaged individuals. These deficits can interfere, at different levels, with prosody, the semantic processing of words and discourse and pragmatic abilities. DEVELOPMENT: Such impairments appear to be present in about half of right-hemisphere-damaged patients and, when present, can result in different clinical profiles. These deficits raise the question of their labeling and their relationship with aphasia. CONCLUSIONS: Given the evolution of the concept of language and the universal definition of aphasia, it is proposed that these deficits correspond to another manifestation of aphasia, thus challenging the idea that they are of a 'non-aphasic' nature.

Impacto de las lesiones del hemisferio derecho sobre las habilidades lingüísticas: perspectivas teórica y clínica / The impact of lesion in the right hemisphere on linguistic skills: theoretical and clinical perspectives

Una lesión en el hemisferio derecho (HD) en pacientes diestros puede provocar alteraciones de lacomunicación verbal. El reciente desarrollo de marcos teóricos centrados en las habilidades discursivas y pragmáticas ha permitido un mejor reconocimiento y descripción de estas alteraciones. Objetivo. Ofrecer un panorama sobre los déficit decomunicación verbal que pueden registrarse en pacientes con lesiones del HD. Desarrollo. Dichos déficit pueden interferir, de manera diferencial, en la prosodia, el procesamiento semántico de las palabras y/o en las habilidades discursivas y pragmáticas.Se calcula que las dificultades pueden estar presentes en la mitad de los lesionados derechos y, en estos casos, dan lugar a perfiles clínicos diferentes. Hablar de lesionados derechos conlleva una discusión no sólo acerca del etiquetado, sino que, además, pone en cuestión las relaciones de estas alteraciones con las afasias. Conclusiones. Dada la evolución del concepto de lenguaje y la definición universal de afasia, proponemos que los daños resultantes de una lesión en el HD pueden considerarse como parte de las afasias. Esto constituye un desafío a la idea de que son déficit de naturaleza no afásica

A lesion of the right hemisphere of right-handers can result in verbal communication impairments.The recent development of theoretical frameworks with regard to discourse and pragmatic abilities, among others, now allows us to recognize and describe these impairments. Aim. To offer an overview of the verbal communication deficits that can befound in right-hemisphere-damaged individuals. These deficits can interfere, at different levels, with prosody, the semantic processing of words and discourse and pragmatic abilities. Development. Such impairments appear to be present in about halfof right-hemisphere-damaged patients and, when present, can result in different clinical profiles. These deficits raise the question of their labeling and their relationship with aphasia. Conclusions. Given the evolution of the concept of languageand the universal definition of aphasia, it is proposed that these deficits correspond to another manifestation of aphasia, thus challenging the idea that they are of a 'non-aphasic' nature

Neural basis of emotional self-regulation in childhood.

Emotional self-regulation plays a pivotal role in socialization and moral development. This capacity critically depends on the development of the prefrontal cortex (PFC). The present functional magnetic resonance imaging study was conducted to identify the neural circuitry underlying voluntary self-regulation of sadness in healthy girls (aged 8-10). A 2 x 2 factorial design was implemented with Emotion (No Sadness vs. Sadness) and Regulation (No Reappraisal vs. Reappraisal) as factors. In the No Reappraisal conditions, subjects were instructed to react normally to neutral and sad film excerpts whereas in the Reappraisal conditions, subjects were asked to voluntarily suppress any emotional reaction in response to comparable stimuli. A significant interaction of the Emotion and Regulation factors revealed that reappraisal of sad film excerpts was associated with bilateral activations of the lateral PFC (LPFC; Brodmann areas [BA] 9 and 10), orbitofrontal cortex (OFC; BA 11), and medial PFC (BA 9 and 10). Significant loci of activations were also detected in the right anterior cingulate cortex (BA 24/32) and right ventrolateral PFC (BA 47). In an identical study previously conducted by our group in adult women [Biol Psychiatry 53 (2003) 502], reappraisal of sad film excerpts was associated with activation of the right OFC (BA 11) and right LPFC (BA 9). The greater number of prefrontal loci of activation found in children relative to adults during voluntary self-regulation of sadness may be related to the immaturity of the prefronto-limbic connections in childhood.

Coexistence of reactive plasticity and neurodegeneration in Alzheimer diseased brains.

Alzheimer's disease (AD) is a pathological process characterized by neuron degeneration and, as recently suggested, brain plasticity. In this work, we compared the reactive plasticity in AD brains associated to O-glycosydically linked glycans, recognized by lectins from Amaranthus leucocarpus (ALL) and Macrobrachium rosenbergii (MRL), and the tau neuritic degeneration. The neuritic degenerative process was evaluated by the quantification of aggregated neuritic structures. Lesions were determined using antibodies against hyperphosphorylated-tau (AD2), amyloid-beta, and synaptophysin. In these conditions, we classified and quantified three pathological structures associated to the neuritic degenerative process: 1) Amyloid-beta deposits (AbetaDs), 2) Classic neuritic plaques (NPs), and 3) Dystrophic neurites clusters (DNCs) lacking amyloid-beta deposits. Reactive plasticity structures were constituted by meganeuritic clusters (MCs) and peri-neuronal sprouting in neurons of the CA4 region of the hippocampus, immunoreactive to synaptophysin (exclusively in AD brains) and GAP-43. Besides, MCs were associated to sialylated O-glycosydically linked glycans as determined by positive labeling with ALL and MRL. Considering that these lectins are specific for the synaptic sprouting process in AD, our results suggest the co-occurrence of of several areas of reactive plasticity and neuron degeneration in AD.

Neural correlates of sad feelings in healthy girls.

Emotional development is indisputably one of the cornerstones of personality development during infancy. According to the differential emotions theory (DET), primary emotions are constituted of three distinct components: the neural-evaluative, the expressive, and the experiential. The DET further assumes that these three components are biologically based and functional nearly from birth. Such a view entails that the neural substrate of primary emotions must be similar in children and adults. Guided by this assumption of the DET, the present functional magnetic resonance imaging study was conducted to identify the neural correlates of sad feelings in healthy children. Fourteen healthy girls (aged 8-10) were scanned while they watched sad film excerpts aimed at externally inducing a transient state of sadness (activation task). Emotionally neutral film excerpts were also presented to the subjects (reference task). The subtraction of the brain activity measured during the viewing of the emotionally neutral film excerpts from that noted during the viewing of the sad film excerpts revealed that sad feelings were associated with significant bilateral activations of the midbrain, the medial prefrontal cortex (Brodmann area [BA] 10), and the anterior temporal pole (BA 21). A significant locus of activation was also noted in the right ventrolateral prefrontal cortex (BA 47). These results are compatible with those of previous functional neuroimaging studies of sadness in adults. They suggest that the neural substrate underlying the subjective experience of sadness is comparable in children and adults. Such a similitude provides empirical support to the DET assumption that the neural substrate of primary emotions is biologically based.

[Mild cognitive impairments in the elderly: a critical review]. / Les troubles cognitifs légers de la personne âgée: revue critique.

The aging of the population leads to increased awareness of problems associated with age-related degenerative dementias. Given that these dementias are progressive in onset, many clinicians and researchers have proposed criteria that allow for the identification of older subjects manifesting cognitive impairment, but not responding to the criteria for dementia. Our knowledge of subjects with mild cognitive impairment is limited; it is, however, established that they present a high risk of developing dementia in the future. Although it is essential to increase our comprehension of their cognitive and functional decline, the study of subjects presenting mild cognitive impairment is compromised due to the existence of numerous non-converging classifications. The goal of the present article is to conduct a critical review of the different classifications of mild cognitive impairment in the elderly in order to attempt to identify the optimal criteria, allowing for a distinction to be made between subjects with mild cognitive impairment, who remain in a stable state and those whose condition evolves to a dementia. These criteria may enable us to describe a homogenuous group of individuals presenting with different rates of dementia risk factors. We present the classifications most frequently used in clinical and research settings. After listing them according to categorial, clinical or dimensional approaches, we performed a critical analysis for each one. Depending on the diagnostic criteria applied, major variations are revealed for the prevalence of cognitive impairment and the incidence of dementia. They are explained by methodological and theoretical shortcomings that we point out and discuss (e.g., reference group, lack of diagnostic criteria or exclusion criteria, high level of subjectivity). Beyond these criticisms, we discuss the challenges to be met in order to reach the optimal identification criteria. Notably, the impact of mild cognitive impairment on daily living activities should be tested with the use of more specific questionnaires/tasks. The goal of the objective definition of cognitive impairment should be to minimize subjectivity in the diagnosis. It is also suggested that sensitive cognitive measures would be used on all aspects of cognition, while recognizing and taking into account all confounding factors (e.g., age, education level). Given the nature and consequences of mild cognitive impairment, an inter-disciplinary approach is suggested (e.g., neurobiological, psychiatric, and genetic cues). A consensus on optimal diagnostic criteria is essential to propose cognitive and pharmacological treatments for the effective prevention of ementia.

The mind and brain scholar as a hitchhiker in the post-Gutenberg galaxy: publishing at 2000 and beyond.

Electronic journal (e-journal) publishing has started to change the ways we think about publishing. However, many scholars and scientists in the mind and brain sciences are still ignorant of the new possibilities and ongoing debates. This paper will provide a summary of the issues involved, give an update of the current discussion, and supply practical information on issues related to e-journal publishing and self-archiving relevant for the mind and brain sciences. Issues such as differences between traditional and e-journal publishing, open archive initiatives, worldwide conventions, quality control, costs involved in e-journal publishing, and copyright questions will be addressed. Practical hints on how to self-archive, how to submit to the e-journal Psycoloquy, how to create an open research archive, and where to find information relevant to e-publishing will be supplied.

Grapheme-phoneme processing of single words.

Often used in cognitive studies measuring reaction times and in functional imaging studies, the subtraction paradigm is based on the comparison of performance on tasks presupposed to refer to different cognitive levels of processing. Within the framework of the study of phonological processing of words, manipulating the grapheme-phoneme transparency of stimuli can represent a means of counteracting the methodological drawbacks inherent to the subtraction paradigm. Thus, the purpose of this study was to determine the effect of the level of difficulty of grapheme-phoneme matching on the processing of transparent and nontransparent words. Grapheme-phoneme matching was carried out both on the final syllable of words and on sublexical segments within the word. The results indicate that processing is faster for the transparent than for the nontransparent stimuli. This task will now have to be reintroduced in brain imaging studies aiming to look at different levels of difficulty for grapheme-phoneme matching.

The effects of left- versus right-hemisphere lesions on the sensitivity to intra- and interconceptual semantic relationships.

Studies on split-brain, normal and brain-damaged subjects suggest differences in the processing of semantic relationships by the two hemispheres. Various authors have conceived of this distinction in terms of the paradigmatic/syntagmatic dissociation, and the connotative and denotative meanings of words, and as reflecting different types of links between words. Drews has suggested that a left-hemisphere lesion would affect the processing of intraconceptual relationships, while a right-hemisphere lesion would impair the processing of interconceptual relationships. The goal of this study was to test this hypothesis, using a number of intra- and interconceptual semantic relationships. Pairs of common words were submitted to left-hemisphere brain-damaged and right-hemisphere brain-damaged subjects. The task required subjects to indicate whether or not there was any relationship between the words. The results only partially support the hypothesis. The right/left opposition applied to only one of three types of intraconceptual relationships (whole-part relation) and to one of two types of interconceptual relationship (same location relation). This partially unexpected result is discussed in reference to other studies.

Conceptual apraxia and semantic memory deficit in Alzheimer's disease: two sides of the same coin?

This study was designed to examine the patterns of apraxic disturbances and the relationships between action knowledge and other measures of semantic knowledge about objects in 10 well-characterized Alzheimer's disease (AD) patients. Five tasks were used to assess components of action knowledge (action-tool relationships, pantomime recognition, and sequential organization of action) and praxis execution (actual use, pantomiming) according to the cognitive model of praxis. Three tasks (verbal comprehension, naming, and a visual semantic matching task) were used to assess verbal-visual semantics. Considering patterns of apraxia first, conceptual apraxia was found in 9 out of the 10 AD patients, suggesting that it is a common feature even in the early stages of AD. Second, we found partly parallel deficits in tests of action-semantic and verbal-visual semantic knowledge in 9 AD patients. Impaired action knowledge was found only in patients with a semantic language deficit. These findings provide no evidence that "action semantics" may be separated from other semantic information. Our results support the view of a unitary semantic system, given that the representations of action-semantic and other semantic knowledge of objects are often simultaneously disrupted in AD.

[Plurality of patterns of cognitive impairment in normal aging and in dementia]. / Pluralité des patrons d'atteinte cognitive accompagnant le vieillissement normal et la démence.

Normal aging, as well as most of the degenerative diseases of the central nervous system characterizing old age, have an impact on cognitive abilities which are obvious as well as increasingly understood. Cognitive changes in normal ageing realize a plurality of possible patterns of cognitive disabilities. Dementias are also well known to be characterized by a plurality of cognitive impairments patterns. The different cognitive patterns are likely to be due to distinct levels of impairments of different domains of cognition, or of different components within one given domain of cognition. These differences are such that in some cases they can even realize double dissociations. The plurality of cognitive impairments patterns in normal aging and in dementia will be discussed as well as the different factors that could contribute to such a plurality. Some of these factors relate to pre-morbid characteristics of the individuals known to influence the functional organization of the brain for cognition. Others--of major importance--are related to the nature and the distribution of the pathophysiological processes underlying normal ageing or a given degenerative disease. It is also reminded that some or many of these factors can interact with more general cognitive factors, such as speed of execution. It is however suggested that, despite of their presence, these general factors partly contribute to the cognitive impairments in neurodegenerative dementia. In this case, the impact of different disease-related factors over a general cognitive factor is probably much greater than in the case of normal aging.

Language development following brain injury in early childhood: a longitudinal case study.

The present longitudinal case study was designed to investigate the possibility that a traumatic brain injury (TBI) occurring during the second year of life, while significant lexical and grammatical competencies are emerging, could have an impact on subsequent language development. Thus, the language development of a very young girl (BL) who suffered a TBI at the age of 17 months was monitored for 6 months following the injury. Different procedures were used to measure her lexical and grammatical development: monthly parental checklists, free-play sessions and word-learning tasks. BL's results were compared with two control groups (n = 5 and 9) matched for age and gender. Overall, the results are consistent with the classical view of acquired language disorders in children: despite an initial decrease in the use of her premorbid vocabulary, BL showed no durable significant impairment on any measure of lexical or grammatical development.

Age-related evolution of the contribution of the right hemisphere to language: absence of evidence.

The age difference observed between Wernicke's and Broca's aphasics has been understood by some authors as an indication of a progressive diminution of the contribution of the right hemisphere to language throughout the life span. To test this hypothesis, 24 right-hemisphere-damaged (RHD) and 24 normal control adults were submitted to six tasks looking at different aspects of language abilities. Results showed that RHDs performed less well than normal subjects on 3 of these tasks, but that this difference was not linked with age (younger than 55 versus older than 65 years). Consequently, these results do not support models of functional brain organization suggesting a decreasing contribution of the right hemisphere to language abilities with age.