948 resultados para Auditory deficiency


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The present study used positron emission tomography (PET) to examine the cerebral activity pattern associated with auditory imagery forfamiliar tunes. Subjects either imagined the continuation of nonverbaltunes cued by their first few notes, listened to a short sequence of notesas a control task, or listened and then reimagined that short sequence. Subtraction of the activation in the control task from that in the real-tune imagery task revealed primarily right-sided activation in frontal and superior temporal regions, plus supplementary motor area(SMA). Isolating retrieval of the real tunes by subtracting activation in the reimagine task from that in the real-tune imagery task revealedactivation primarily in right frontal areas and right superior temporal gyrus. Subtraction of activation in the control condition from that in the reimagine condition, intended to capture imagery of unfamiliarsequences, revealed activation in SMA, plus some left frontal regions. We conclude that areas of right auditory association cortex, together with right and left frontal cortices, are implicated in imagery for familiartunes, in accord with previous behavioral, lesion and PET data. Retrieval from musical semantic memory is mediated by structures in the right frontal lobe, in contrast to results from previous studies implicating left frontal areas for all semantic retrieval. The SMA seems to be involved specifically in image generation, implicating a motor code in this process.

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The present study used positron emission tomography (PET) to examine the cerebral activity pattern associated with auditory imagery for familiar tunes. Subjects either imagined the continuation of nonverbal tunes cued by their first few notes, listened to a short sequence of notes as a control task, or listened and then reimagined that short sequence. Subtraction of the activation in the control task from that in the real-tune imagery task revealed primarily right-sided activation in frontal and superior temporal regions, plus supplementary motor area (SMA). Isolating retrieval of the real tunes by subtracting activation in the reimagine task from that in the real-tune imagery task revealed activation primarily in right frontal areas and right superior temporal gyrus. Subtraction of activation in the control condition from that in the reimagine condition, intended to capture imagery of unfamiliar sequences, revealed activation in SMA, plus some left frontal regions. We conclude that areas of right auditory association cortex, together with right and left frontal cortices, are implicated in imagery for familiar tunes, in accord with previous behavioral, lesion and PET data. Retrieval from musical semantic memory is mediated by structures in the right frontal lobe, in contrast to results from previous studies implicating left frontal areas for all semantic retrieval. The SMA seems to be involved specifically in image generation, implicating a motor code in this process.

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Four experiments examined how people operate on memory representations of familiar songs. The tasks were similar to those used in studies of visual imagery. In one task, subjects saw a one word lyric from a song and then saw a second lyric; then they had to say if the second lyric was from the same song as the first. In a second task, subjects mentally compared pitches of notes corresponding to song lyrics. In both tasks, reaction time increased as a function of the distance in beats between the two lyrics in the actual song, and in some conditions reaction time increased with the starting beat of the earlier lyric. Imagery instructions modified the main results somewhat in the first task, but not in the second, much harder task. The results suggest that song representations have temporal-like characteristics. (PsycINFO Database Record (c) 2012 APA, all rights reserved)

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Most people intuitively understand what it means to “hear a tune in your head.” Converging evidence now indicates that auditory cortical areas can be recruited even in the absence of sound and that this corresponds to the phenomenological experience of imagining music. We discuss these findings as well as some methodological challenges. We also consider the role of core versus belt areas in musical imagery, the relation between auditory and motor systems during imagery of music performance, and practical implications of this research.

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Auditory imagery is more than just mental “replaying” of tunes in one’s head. I will review several studies that capture characteristics of complex and active imagery tasks, using both behavioral and neuroscience approaches. I use behavioral methods to capture people’s ability to make emotion judgments about both heard and imagined music in real time. My neuroimaging studies look at the neural correlates of encoding an imagined melody, anticipating an upcoming tune, and also imagining tunes backwards. Several studies show voxel-by-voxel correlates of neural activity with self-report of imagery vividness. These studies speak to the ways in which musical imagery allows us not just to remember music, but also how we use those memories to judge temporally changing aspects of the musical experience.

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The vocal imitation of pitch by singing requires one to plan laryngeal movements on the basis of anticipated target pitch events. This process may rely on auditory imagery, which has been shown to activate motor planning areas. As such, we hypothesized that poor-pitch singing, although not typically associated with deficient pitch perception, may be associated with deficient auditory imagery. Participants vocally imitated simple pitch sequences by singing, discriminated pitch pairs on the basis of pitch height, and completed an auditory imagery self-report questionnaire (the Bucknell Auditory Imagery Scale). The percentage of trials participants sung in tune correlated significantly with self-reports of vividness for auditory imagery, although not with the ability to control auditory imagery. Pitch discrimination was not predicted by auditory imagery scores. The results thus support a link between auditory imagery and vocal imitation.

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Investigations of gray matter changes in relation with auditory verbal hallucinations (AVH) have reported conflicting results. Assuming that alterations in gray matter might be related to certain symptoms in schizophrenia this study aimed to investigate changes in cortical thickness specific to AVH. It was hypothesized that schizophrenia patients suffering from persistent AVH would show significant differences in cortical thickness in regions involved in language-production and perception when compared to schizophrenia patients which had never experienced any hallucinations.

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Abnormal perceptions and cognitions in schizophrenia might be related to abnormal resting states of the brain. Previous research found that a specific class (class D) of sub-second electroencephalography (EEG) microstates was shortened in schizophrenia. This shortening correlated with positive symptoms. We questioned if this reflected positive psychotic traits or present psychopathology.

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Congenital isolated ACTH deficiency (IAD) is a rare disease characterized by low plasma ACTH and cortisol levels and preservation of all other pituitary hormones. This condition was poorly defined before we identified TPIT, a T-box transcription factor with a specific role in differentiation of the corticotroph lineage in mice and humans, as its principal molecular cause.

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P450 oxidoreductase (POR) is the electron donor for all microsomal P450s including steroidogenic enzymes CYP17A1, CYP19A1 and CYP21A2. We found a novel POR mutation P399_E401del in two unrelated Turkish patients with 46,XX disorder of sexual development. Recombinant POR proteins were produced in yeast and tested for their ability to support steroid metabolizing P450 activities. In comparison to wild-type POR, the P399_E401del protein was found to decrease catalytic efficiency of 21-hydroxylation of progesterone by 68%, 17α-hydroxylation of progesterone by 76%, 17,20-lyase action on 17OH-pregnenolone by 69%, aromatization of androstenedione by 85% and cytochrome c reduction activity by 80%. Protein structure analysis of the three amino acid deletion P399_E401 revealed reduced stability and flexibility of the mutant. In conclusion, P399_E401del is a novel mutation in POR that provides valuable genotype-phenotype and structure-function correlation for mutations in a different region of POR compared to previous studies. Characterization of P399_E401del provides further insight into specificity of different P450s for interaction with POR as well as nature of metabolic disruptions caused by more pronounced effect on specific P450s like CYP17A1 and aromatase.

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Despite the differences in the main characteristics between the autosomal dominant form of GH deficiency (IGHD II) and the bioinactive GH syndrome, a common feature of both is their impact on linear growth leading to short stature in all affected patients.

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A number of mathematical models for predicting growth and final height outcome have been proposed to enable the clinician to 'individualize' growth-promoting treatment. However, despite optimizing these models, many patients with isolated growth hormone deficiency (IGHD) do not reach their target height. The aim of this study was to analyse the impact of polymorphic genotypes [CA repeat promoter polymorphism of insulin-like growth factor-I (IGF-I) and the -202 A/C promoter polymorphism of IGF-Binding Protein-3 (IGFBP-3)] on variable growth factors as well as final height in severe IGHD following GH treatment. DESIGN, PATIENTS AND CONTROLS: One hundred seventy eight (IGF-I) and 167 (IGFBP-3) subjects with severe growth retardation because of IGHD were studied. In addition, the various genotypes were also studied in a healthy control group of 211 subjects.

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Despite more than 2 decades of neuroimaging investigations, there is currently insufficient evidence to fully understand the neurobiological substrate of auditory hallucinations (AH). However, some progress has been made with imaging studies in patients with AH consistently reporting altered structure and function in speech and language, sensory, and nonsensory regions. This report provides an update of neuroimaging studies of AH with a particular emphasis on more recent anatomical, physiological, and neurochemical imaging studies. Specifically, we provide (1) a review of findings in schizophrenia and nonschizophrenia voice hearers, (2) a discussion regarding key issues that have interfered with progress, and (3) practical recommendations for future studies.