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HIV neurological complications
Published in Avindra Nath, Joseph R. Berger, Clinical Neurovirology, 2020
Functional imaging is also gaining a greater role in this field. Blood oxygen level-dependent (BOLD) functional magnetic resonance imaging aims to assay the regional differences in cerebral blood flow and blood oxygenation as surrogate markers for brain activity during a particular task. A recent meta-analysis of fMRI studies in hand identified the fronto-striatal system as a common area of dysfunction, with hyperactivation of the left inferior frontal gyrus and left caudate [140]. Positron emission tomography (PET) is another functional technique that has been applied to HAND using a number of different ligands. Fluorodeoxyglucose (FDG)-PET assays the metabolic activity of different areas of tissue, and this technique has demonstrated reduced cerebral metabolic rates for glucose in HIV patients [141], as well as altered metabolism in the basal ganglia (and initial hypermetabolism in the striatum in particular) in HAND [142]. A number of other ligands have also been employed with differing molecular targets and insights (Table 11.3).
Preparing the Patient for the fMRI Study and Optimization of Paradigm Selection and Delivery
Published in Andrei I. Holodny, Functional Neuroimaging, 2019
The frontal speech areas mostly comprise the inferior frontal gyrus (pars triangularis and pars opercularis) of the left hemisphere (Fig. 1A). Broadly, the frontal speech area is involved in speech production. Lesions to this area produce a halting, expressive, or nonfluent aphasia (also termed “Broca’s aphasia”). Most commonly, patients with expressive aphasias perform well on measures of speech comprehension but display agrammatic or telegraphic speech (simplified, staccato-like sentences).
Biological and genetic factors in DCD
Published in Anna L. Barnett, Elisabeth L. Hill, Understanding Motor Behaviour in Developmental Coordination Disorder, 2019
Melissa K. Licari, Daniela Rigoli, Jan P. Piek
One of the more consistent findings across studies is varying patterns of activation in the frontal lobe (Kashiwagi et al., 2009; Licari et al., 2015; Reynolds et al., 2015; Zwicker et al., 2010, 2011), a region involved in the planning and execution of movement, along with the higher order processes. Altered activity in the dorsolateral prefrontal cortex has been reported across studies utilising tasks with higher visuomotor demands (Debrabant et al., 2013; Querne et al., 2008; Zwicker et al., 2011), indicating issues with attentional control, which may also impact on motor planning. The inferior frontal gyrus is another cortical region reported more than once (Debrabant et al., 2013; Licari et al., 2015; Reynolds et al., 2015), involved in our ability to observe and imitate movement, forming part of the parietal-premotor network.
Language production and implicit statistical learning in typical development and children with acquired language disorders: an exploratory study
Published in Speech, Language and Hearing, 2022
Xue Ting Joelle Mok, Siew Li Goh, James Douglas Saddy, Rosemary Varley, Vitor Zimmerer
Neuropsychological studies suggest an overlap in the neural bases of statistical learning in language processing and statistical learning in other domains. Findings in statistical learning studies can vary substantially depending on which experimental paradigm is employed. Studies using speech-segmentation paradigms have identified the left inferior frontal gyrus and left superior temporal gyrus (Karuza et al., 2013; McNealy, Mazziotta, & Dapretto, 2006, 2010; Plante, Patterson, Sandoval, Vance, & Asbjørnsen, 2017). Artificial grammar learning studies in different sensory modalities using probabilistic finite-state grammars have identified, beyond activation in sensory-modality specific areas, frontal cortical activation, including left inferior frontal gyrus, and subcortical activation, particularly of basal ganglia (Conway & Pisoni, 2008; Newman-Norlund, Frey, Petitto, & Grafton, 2006; Petersson, Folia, & Hagoort, 2012).
Comorbidity between ADHD and anxiety disorders across the lifespan
Published in International Journal of Psychiatry in Clinical Practice, 2019
Elisa D’Agati, Paolo Curatolo, Luigi Mazzone
Patients with ADHD and patients GAD that represents the most common anxiety disorder in comorbidity with ADHD (Souza et al., 2005) share some neurodevelopmental abnormalities in the brain. MRI studies demonstrated an increased grey matter volume in the amygdala, in the dorsomedial prefrontal cortex (PFC), and grey matter volume changes on the right cerebellar hemisphere in patients with GAD (Hilbert, Evens, Maslowski, Wittchen, & Lueken, 2015). Another study showed a grey matter increase in superior temporal gyrus and a decrease in medial and superior frontal gyri in adolescents with GAD (Strawn et al., 2013). Increased grey matter volume in the right inferior frontal gyrus, and in right PFC was documented in patients with ADHD aged 9–16 years (Garrett et al., 2008; Semrud-Clikeman, Pliszka, Bledsoe, & Lancaster, 2014). A systematic review of fMRI studies in patients with GAD, reported that neuroimaging studies differed largely in methodology, making it difficult to identify common findings (Mochcovitch, da Rocha Freire, Garcia, & Nardi, 2014).
Primary progressive aphasia and the FTD-MND spectrum disorders: clinical, pathological, and neuroimaging correlates
Published in Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 2019
Giulia Vinceti, Nicholas Olney, Maria Luisa Mandelli, Salvatore Spina, H. Isabel Hubbard, Miguel A. Santos-Santos, Christa Watson, Zachary A. Miller, Catherine Lomen-Hoerth, Paolo Nichelli, Bruce L. Miller, Lea T. Grinberg, William W. Seeley, Maria Luisa Gorno-Tempini
The PA-MND (n = 10) group compared to controls showed peak of GM atrophy in the left temporal pole, hippocampus, fusiform gyrus, amygdala, and inferior temporal gyrus, with a specular area localized in the right parahippocampal gyrus (Figure 3(a)). Also, the left inferior frontal gyrus, pars opercularis and the precentral gyrus appeared atrophic. In the bvFTD-MND (n = 22) group, atrophy emerged mainly in the left insular lobe, left inferior frontal gyrus pars triangularis and orbitalis, and, symmetrically, in the right insular lobe and putamen; also the left temporal pole, amygdala, hippocampus, rectal and superior orbital gyrus were involved, as long with left thalamus (Figure 3(b)). Also right anterior and midcingulate cortex were atrophic. A smaller cluster in the left inferior frontal gyrus at the edge with the precentral gyrus (Area 44) was also found. ALS (n = 9) group showed atrophy mainly in the left precentral gyrus (Area 4p, Figure 3(c)).