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Late-onset amnestic mild cognitive impairment (aMCI) with long disease course and slow progression has been recently recognized as a possible phenotypical expression of a limbic-predominant neurodegenerative disorder. Basic emotion recognition ability crucially depending on temporo-limbic integrity is supposed to be impaired in this group of MCI subjects presenting a selective vulnerability of medio-temporal and limbic regions. However, no study specifically investigated this issue.
Methods:
Hereby, we enrolled 30 aMCI with a biomarker-based diagnosis of Alzheimer’s disease (i.e., aMCI-AD, n = 16) or a biomarker evidence of selective medio-temporal and limbic degeneration (aMCI-mTLD, n = 14). Ekman-60 Faces Test (Ek-60F) was administered to each subject, comparing the performance with that of 20 healthy controls (HCs).
Results:
aMCI-mTLD subjects showed significantly lower Ek-60F global scores compared to HC (p = 0.001), whose performance was comparable to aMCI-AD. Fear (p = 0.02), surprise (p = 0.005), and anger (p = 0.01) recognition deficits characterized the aMCI-mTLD performance. Fear recognition scores were significantly lower in aMCI-mTLD compared to aMCI-AD (p = 0.04), while no differences were found in other emotions.
Conclusions:
Impaired social cognition, suggested by defective performance in emotion recognition tasks, may be a useful cognitive marker to detect limbic-predominant aMCI subjects among the heterogeneous aMCI population.
A previous review of the neuroimaging studies in obstructive sleep apnea (OSA) called for specific attention to longitudinal studies of the treatment effects of OSA on neuroimaging. This chapter focuses on those studies where treatment effects were considered. The structural studies suggest that there are some notable changes in the structure of the human brain when continuous positive airway pressure (CPAP) is used to correct OSA. Some of these changes are even associated with cognitive changes in the expected cognitive domains and are seen with as little as only three months of treatment. The functional imaging studies together suggest that changes in brain function associated with working memory are evident when comparing treatment with no-treatment conditions in patients with OSA. Specifically, treatment often results in the recruitment of fewer cognitive resources to perform at the same level or better.
Normative theories of reasoning distinguish two kinds of persuasive arguments depending on the inferential connection between premises and conclusion. If the truth of an argument's premises guarantee that of its conclusion, the argument is called valid, whereas if the premises merely enhance the plausibility of the conclusion, the argument is probabilistically strong. Human intuition about validity and probability is limited to inferences of moderate size and reveals systematic imperfections even when applied to simple cases. Nonetheless, starting from adolescence both forms of reasoning are recognizable approximations to their normative counterparts [3, 6, 11].
What is the psychological relation between deductive and probabilistic reasoning? One influential theory conceives both kinds of reasoning as involving the manipulation of ‘mental models’. In this view, an argument is evaluated by constructing alternative models of its premises, where each model is a representation of potential circumstances that would render the premises true. The argument is then judged to be probabilistically strong in case a large proportion of the models generated for the premises render the conclusion true as well; the intuition of validity arises from the limiting case in which this proportion reaches one. Within epistemology, such an account of the relation between validity and probability was proposed by Wittgenstein [[41], §5.15], and followed up by de Finetti [9] and others. A psychological version of the same idea has recently been proposed by Johnson-Laird [23], where it receives detailed and persuasive defense.
Three types of problems are raised in this commentary: On the linguistic side, we emphasize the importance of an appropriate definition of the different domains of linguistics. This is needed to define the domains (lexicon-syntax-semantics) to which transformational relations apply. We then question the concept of Broca's aphasia as a “functional” syndrome, associated with a specific lesion. Finally, we discuss evidence from functional brain imaging. The breadth and potential impact of such evidence has grown considerably in the last few years, expanding our knowledge of the multiple contributions of the “Broca's region” to phonological, lexical-semantic, and syntactic processing. “Lumping” under diagnostic labels, such as Broca's aphasia, should be replaced by more detailed linguistic and neurological descriptions of the clinical cases.
Functional neuroimaging, used in conjunction with experimental cognitive tasks, has been extremely successful in establishing functional specialization as a principle of brain organization in man. Positron emission tomography activation techniques and functional magnetic resonance imaging assess localized increases in cerebral blood flow associated with mental processes. The advent of these noninvasive neuroimaging techniques opened a “new era” in the investigation of language organization in healthy individuals. Neuroimaging studies of bilinguals and polyglots have highlighted the potential role of variables, such as age of acquisition, degree of proficiency, level of exposure, dominance/maternality on functional brain mapping of multiple languages. Consistent results indicate that attained proficiency, and maybe language exposure, are more important than the age of acquisition as a determinant of the cerebral representation of languages in bilinguals/polyglots. Indeed, increasing language proficiency appears to be associated at the neural level with the engagement of a common network within the dedicated language areas. Here we have reviewed the functional imaging literature on bilingualism.
We used [18F]FDG and PET in patients with obsessive–compulsive disorder (OCD) to evaluate cerebral metabolic involvement before and after treatment with serotonin-specific reuptake inhibitors.
Method
In 11 untreated, drug-free adults, regional cerebral metabolic rate for glucose (rCMRglu) was compared with that of 15 age-matched normal controls.
Results
rCMRglu values were significantly increased in the cingulate cortex, thalamus and pallidum/putamen complex. After treatment a significant improvement in obsessive–compulsive symptoms on the Y-BOC scale (t = 3.59, P < 0.01) was associated with a significant bilateral decrease of metabolism in the whole cingulate cortex (P < 0.001). Clinical and metabolic data were significantly intercorrelated (Kendall's τ = 0.65; P < 0.01).
Conclusions
These findings indicate that OCD is associated with functional hyperactivity of a selected neuronal network and that treatment to reduce symptoms may have a selective neuromodulatory effect on cingulate cortex.
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