Less is more: neural mechanisms underlying anomia treatment in chronic aphasic patients.

Previous research with aphasic patients has shown that picture naming can be facilitated by concurrent phonemic cueing [e.g.initial phoneme(s) of the word that the patient is trying to retrieve], both as an immediate word retrieval technique, and when practiced repeatedly over time as a long-term anomia treatment. Here, to investigate the neural mechanisms supporting word retrieval, we adopted—for the first time—a functional magnetic resonance imaging task using the same naming procedure as it occurs during the anomia treatment process. Before and directly after a 6-week anomia treatment programme, 18 chronic aphasic stroke patients completed our functional magnetic resonance imaging protocol—a picture naming task aided by three different types of phonemic cues (whole words, initial phonemes, final phonemes) and a noise-control condition. Patients completed a naming task based on the training materials, and a more general comprehensive battery of language tests both before and after the anomia treatment, to determine the effectiveness and specificity of the therapy. Our results demonstrate that the anomia treatment was effective and specific to speech production, significantly improving both patients’ naming accuracy and reaction time immediately post-treatment (unstandardized effect size: 29% and 17%, respectively; Cohen’s d: 3.45 and 1.83). Longer term gains in naming were maintained 3 months later. Functional imaging results showed that both immediate and long-term facilitation of naming involved a largely overlapping bilateral frontal network including the right anterior insula, inferior frontal and dorsal anterior cingulate cortices, and the left premotor cortex. These areas were associated with a neural priming effect (i.e. reduced blood oxygen level-dependent signal) during both immediate (phonemically-cued versus control-cue conditions), and long-term facilitation of naming (i.e. treated versus untreated items). Of note is that different brain regions were sensitive to different phonemic cue types. Processing of whole word cues was associated with increased activity in the right angular gyrus; whereas partial word cues (initial and final phonemes) recruited the left supplementary motor area, and right anterior insula, inferior frontal cortex, and basal ganglia. The recruitment of multiple and bilateral areas may help explain why phonemic cueing is such a successful behavioural facilitation tool for anomia treatment. Our results have important implications for optimizing current anomia treatment approaches, developing new treatments, and improving speech outcome for aphasic patient

Copy number deletion burden is associated with cognitive, structural, and resting-state network differences in patients with schizophrenia

Total burden of copy number deletions has been implicated in schizophrenia risk and has been associated with reduced cognitive functioning. The current study aims to replicate the cognitive findings and investigate regional grey and white matter volumes. Moreover, it will explore resting-state networks for correlations between functional connectivity and total deletion burden. All imaging differences will be investigated for correlations with cognitive differences. Seventy-eight patients with chronic schizophrenia, who formed a subset of a large genome-wide association study (GWAS), were assessed for intelligence, 34 had structural magnetic resonance imaging, 33 had resting-state functional magnetic resonance imaging, and 32 had diffusion tensor imaging (DTI). Total deletion burden was negatively associated with IQ performance and positively associated with regional volumes in the striatum bilaterally and in the right superior temporal gyrus and white-matter in the corpus callosum. Correlations were identified between deletion burden and both hyper and hypoconnectivity within the default-mode network and hypoconnectivity within the cognitive control network. The functional connectivity correlations with deletion burden were also correlated with the IQ differences identified. Total deletion burden affects regional volumes and resting-state functional connectivity in key brain networks in patients with schizophrenia. Moreover, effects of deletions on cognitive functioning in may be due to inefficiency of key brain networks as identified by dysconnectivity in resting-state networks

Functional neuroimaging of visual creativity: a systematic review and meta-analysis

Introduction: The generation of creative visual imagery contributes to technological and scientific innovation, and production of visual art. The underlying cognitive and neural processes are however poorly understood. Methods: This review synthesises functional neuroimaging studies of visual creativity. Seven functional magnetic resonance imaging (fMRI) and 19 electroencephalography (EEG) studies were included, comprising 27 experiments and around 800 participants. Results: Activation likelihood estimation meta-analysis of the fMRI studies comparing visual creativity to non-rest control tasks yielded significant clusters in thalamus, left fusiform gyrus, and right middle and inferior frontal gyri. The EEG studies revealed a tendency for decreased alpha power during visual creativity compared to baseline, but comparisons of visual creativity to non-rest control tasks revealed inconsistent findings. Conclusions: The findings are consistent with suggested contributions to visual creativity of prefrontally-mediated inhibition, evaluation and working memory, as well as visual imagery processes. Findings are discussed in relation to prominent theories of the neural basis of creativity

Diversity of the inferior frontal gyrus-A meta-analysis of neuroimaging studies

Purpose: The inferior frontal gyrus (IFG) has attracted a lot of interest due to its involvement in motor control and language processing. More recently, it has also been implicated for the processing of empathy. The aim of this meta-analysis was to investigate if neuroimaging studies in humans reveal distinct foci related to empathy as compared to those in motor and speech control in the IFG. Materials and methods: We reviewed MEDLINE for functional imaging studies on healthy subjects published between 1991 and 2007. With the search terms " inferior frontal gyrus" , and " statistical parametric mapping" 485 studies were identified. We performed a non-hierarchical cluster-centre analysis of the stereotactic coordinates of the reported 1042 significant activation peaks and investigated seven functional categories using a score of specificity (SCSP). Results: We found four significant, spatially distinct clusters. Three left-hemispheric clusters included one for processing of empathy, one closely adjacent for semantic and phonological processing, and one for working memory, while one cluster for fine movement control was located in the right hemisphere. Conclusions: This meta-analysis demonstrates a spatio-functional diversity of the left human IFG for processing of language, working memory and empathy. Notably, phonological and semantic processing collapsed into one cluster. Fine movement control located in a cluster in the right IFG occurred in a virtually mirror-like location to processing of empathy in the left hemisphere. These observations are in accordance with the notion of the mirror neuron system mediating specialized links between perception and action. © 2011 Elsevier B.V