Yves Joanette

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.

Amygdala responses to nonlinguistic emotional vocalizations

Whereas there is ample evidence for a role of the amygdala in the processing of visual emotional stimuli, particularly those with negative value, discrepant results have been reported regarding amygdala responses to emotional auditory stimuli. The present study used event-related functional magnetic resonance imaging to investigate cerebral activity underlying processing of emotional nonlinguistic vocalizations, with a particular focus on neural changes in the amygdala. Fourteen healthy volunteers were scanned while performing a gender identification task. Stimuli, previously validated on emotional valence, consisted of positive (happiness and sexual pleasure) and negative (sadness and fear) vocalizations, as well as emotionally neutral sounds (e.g., coughs). Results revealed bilateral amygdala activation in response to all emotional vocalizations when compared to neutral stimuli. These findings suggest that the generally accepted involvement of the amygdala in the perception of emotional visual stimuli, such as facial expressions, also applies to stimuli within the auditory modality. Importantly, this amygdala response was observed for both positive and negative emotional vocalizations.

Is voice processing species-specific in human auditory cortex? An fMRI study

Recent studies suggested a sensitivity of regions of the human superior temporal sulcus (STS) to the sound of the human voice. However, the question of the species specificity of this response is still open. Healthy adult volunteers were scanned in an event-related fMRI design to compare responses in the STS to human and animal vocalizations, as well as to control nonvocal sounds (e.g., musical instruments). Bilateral activation of anterior STS was observed for human vocalizations, when contrasted with both nonvocal sounds and animal vocalizations. Animal vocalizations, compared to nonvocal sounds, elicited a more restricted left STS activation, although this region responded even more strongly to human vocalizations. This study provides the first evidence suggesting a species specificity in STS responses to vocalizations in humans.

Diagnosis and treatment of dementia: 3. Mild cognitive impairment and cognitive impairment without dementia.

Background: Mild cognitive impairment and cognitive impairment, no dementia, are emerging terms that encompass the clinical state between normal cognition and dementia in elderly people. Controversy surrounds their characterization, definition and application in clinical practice. In this article, we provide physicians with practical guidance on the definition, diagnosis and treatment of mild cognitive impairment and cognitive impairment, no dementia, based on recommendations from the Third Canadian Consensus Conference on the Diagnosis and Treatment of Dementia, held in March 2006. Methods: We developed evidence-based guidelines using systematic literature searches, with specific criteria for study selection and quality assessment, and a clear and transparent decision-making process. We selected studies published from January 1996 to December 2005 that had mild cognitive impairment or cognitive impairment, no dementia, as the outcome. Subsequent to the conference, we searched for additional articles published between January 2006 and January 2008. We graded the strength of evidence using the criteria of the Canadian Task Force on Preventive Health Care. Results: We identified 2483 articles, of which 314 were considered to be relevant and of good or fair quality. From a synthesis of the evidence in these studies, we made 16 recommendations. In brief, family physicians should be aware that most types of dementia are preceded by a recognizable phase of mild cognitive decline. They should be familiar with the concepts of mild cognitive impairment and of cognitive impairment, no dementia. Patients with these conditions should be closely monitored because of their increased risk for dementia. Leisure activities, cognitive stimulation and physical activity could be promoted as part of a healthy lifestyle in elderly people and those with mild cognitive impairment. Vascular risk factors should be treated optimally. No other specific therapies can yet be recommended. Interpretation: Physicians will increasingly see elderly patients with mild memory loss, and learning an approach to diagnosing states such as mild cognitive impairment is now warranted. Close monitoring for progression to dementia, promotion of a healthy lifestyle and treatment of vascular risk factors are recommended for the management of patients with mild cognitive impairment.

Pointing with left vs right hand in left visual field neglect

The authors report the detection performances of three subjects with unilateral left visual neglect as they were submitted to a closed-loop manual pointing task in the reaching field. Results show, for all three subjects, better detection performances when manual pointing was executed with the left hand--i.e. contralateral to the lesion--than when made with the right hand. Given that, for both hands, signal detection conditions were the same, these results are discussed according to: other studies having showed changes in the expression of neglect as induced by changes in the nature or the strategy of the task; the concept of an indissociable sensorimotor central processing; and one of the models put forward to account for unilateral spatial neglect which includes a motor representation.

Training-induced brain remapping in chronic aphasia: a pilot study.

Background. The neural correlates of training-induced improvements of cognitive functions after brain damage remain still scarcely understood. In the specific case of aphasia, although several investigations have addressed the issue of the neural substrates of functional recovery, only a few studies have attempted to assess the impact of language training on the damaged brain. Aims. The main goal of this study was to examine the neurobiological correlates of improved picture-naming performance in 2 aphasic patients who received intensive and specific training for a chronic and severe phonological anomia. Methods. In both participants, picture-naming performance was assessed before and after phonological cueing training. Training-induced changes in patients’ performance were correlated to brain activity patterns as revealed by pre- and post-training event-related functional magnetic resonance imaging scanning. Results. Training-induced improvement was observed concurrently with changes in the brain activation patterns. Better performance was observed in the patient with the smaller lesion, partially sparing Broca’s area, who showed a left perilesional reactivation. Conversely, the patient with complete destruction of Broca’s area showed a posttraining activation in the right mirror frontal region. Conclusions. The results show that, even in the chronic stage, phonological strategies may improve impaired naming and induce cerebral reorganization.

Wayfinding in dementia of the Alzheimer type: planning abilities.

This paper reports on wayfinding in dementia, in particular the ability to develop decision plans for solving wayfinding problems in unfamiliar settings. Fourteen patients diagnosed as having mild to moderate dementia of the Alzheimer type (DAT), and 28 normal elderly were asked to reach a destination in a large hospital setting, and to return to the point of departure. Verbalizations of all subjects were recorded, transcribed, and content-analyzed in order to identify the decisions made during the trip and to establish their functional relationships revealing their planning abilities. Results showed that all DAT patients failed to reach the destination and return to the point of departure without errors. Compared to normal elderly subjects, their overall decision plans were poorly structured, indicating basic problem-solving disorders. However, they were able to solve well-defined problems and develop sub-plans in routine situations when the necessary information was readily available. Nondiscriminatory reading of irrelevant information was also observed and tended to interfere with problem-solving.

Linguistic and other psychological aspects of paroxysmal aphasia

Abstract A case of paroxysmal aphasia is reported. Aphasic spells occurred, in this patient, without modification in consciousness and without involvement of behaviors others than those related to oral and written speech and language. Longer spells successively recapitulated the clinical pictures of global, Wernickes, conduction, and amnestic aphasia. Besides aphasiological evaluations, neurological, psychometrical, electroencephalographical, and CT-scan documents were obtained. The discussion bears on four main points: the linguistic characteristics of paroxysmal aphasia as compared to those of aphasias of other etiologies; Pierre Maries oneness doctrine of aphasia; the mutual relationships of language and thought (in aphasia); the affective experience lived by one with severe aphasia, with special reference to the notion of anosognosia.

Mild cognitive impairment and cognitive impairment, no dementia: Part A, concept and diagnosis

Mild cognitive impairment (MCI) and cognitive impairment, no dementia (CIND) are controversial emerging terms that encompass the clinical state between elderly normal cognition and dementia. This article reviews recent work on the classification of MCI and CIND, their prognosis, and diagnostic approaches and presents evidence‐based recommendations approved at the meeting of the Third Canadian Consensus Conference on the Diagnosis and Treatment of Dementia (CCCDTD3) held in Montreal in March, 2006. New short tools such as the Montreal Cognitive Assessment are making it easier for family physicians to confidently attach the label of MCI.

Criterion-specific reduction of verbal fluency in right brain-damaged right-handers

Thirty-five vascular right brain-damaged (RBD) and 20 control (C) subjects were submitted to a verbal fluency task for which acceptability criteria were either semantic or formal. Results showed that subjects with a vascular lesion limited to the right hemisphere do show a statistically significant reduction of verbal fluency as compared to controls, that this reduction in verbal fluency is only present when the criterion is semantic, and that such a reduction is independent from the frontal or non-frontal topography of the lesion. These results tend to agree with the general conception of a--non-exclusive--right-hemisphere contribution to lexico-semantic processing, and more specifically to its semantic aspects.