Implicit Contextual Learning in Spinocerebellar Ataxia

Objective: Cerebellum is traditionally associated with motor functions, but recently its functions were broadened to include cognitive and affective functions as well. The impairment of these nonmotor functions was subsumed under the term cerebellar cognitive-affective syndrome (CCAS). Spinocerebellar ataxias (SCAs) are a family of hereditary degeneration, which is associated with progressive atrophy of the cerebellum. This study aimed to examine the cerebellar contribution to nonmotor implicit learning, which is the ability to acquire visual contextual information via repeated spatial configurations from the environment without conscious awareness in patients with SCA. Method: Twenty patients with SCA and matched healthy controls performed implicit contextual learning task that is a nonmotor. implicit, visual learning task consisting displays of a target (letter 1) and a number of distractors (letter L). Results: We found implicit contextual learning impairment vis-a-vis spared visuomotor skill learning in SCA. Moreover, this impairment did not correlate with any other measure, including demographics. clinical measures. and neuropsychological measures. Conclusion: These findings broaden the role of cerebellum in nonmotor. implicit, spatial learning processes

Affective theory of mind in human aging: is there any relation with executive functioning?

PubMed ID: 30994403Theory of Mind (ToM) refers to the ability to make inferences on other’s mental or emotional states. Although there is evidence suggesting that impaired executive functions due to aging could have a negative impact on cognitive ToM, there is still controversy about the effect of age and age-related executive dysfunctions on affective ToM. To investigate affective ToM in healthy aging and its relationship with executive functions, we examined Reading Mind in the Eyes Test (RMET) performance and executive functions among young and older adults. There was no significant difference between age groups regarding their RMET scores. While affective ToM was correlated to executive functioning within the younger group, short term memory was found to be associated with RMET performance among older participants. Furthermore, within the older group, women performed better than men. Our findings suggest a preserved ability of affective ToM in healthy aging, which appears to be independent of executive functioning.Publisher's Versio

Resting-state fMRI analysis in apathetic Alzheimer's disease

PURPOSEDiagnosis of comorbid psychiatric conditions are a significant determinant for the prognosis of neurodegenerative diseases. Apathy, which is a behavioral executive dysfunction, frequently accompanies Alzheimer's disease (AD) and leads to higher daily functional loss. We assume that frontal lobe hypofunction in apathetic AD patients are more apparent than the AD patients without apathy. This study aims to address the neuroanatomical correlates of apathy in the early stage of AD using task-free functional magnetic resonance imaging (MRI).METHODSPatients (n=20) were recruited from the Neurology and Psychiatry Departments of Istanbul University, Istanbul School of Medicine whose first referrals were 6- to 12-month history of progressive cognitive decline. Patients with clinical dementia rating 0.5 and 1 were included in the study. The patient group was divided into two subgroups as apathetic and non-apathetic AD according to their psychiatric examination and assessment scores. A healthy control group was also included (n=10). All subjects underwent structural and functional MRI. The resting-state condition was recorded eyes open for 5 minutes.RESULTSThe difference between the three groups came up in the pregenual anterior cingulate cortex (pgACC) at the trend level (P = 0.056). Apathetic AD group showed the most constricted activation area at pgACC.CONCLUSIONThe region in and around anterior default mode network (pgACC) seems to mediate motivation to initiate behavior, and this function appears to weaken as the apathy becomes more severe in AD.Istanbul Universit

Modelling the Stroop effect: A connectionist approach

A connectionist model, which simulates the operation of prefrontal circuits during Stroop task is proposed. The Stroop test has traditionally been used as a measure of cognitive inhibition. The task is to inhibit an over-learned, habitual response (i.e., reading color words) in favor of an unusual, novel requirement (i.e., naming incongruously printed colors of color words). The longer durations in completing the task indicate an inability to inhibit habitual but contextually inappropriate response tendencies, which is suggestive of a prefrontal dysfunction. The connectionist model is designed adapting artificial neural networks (ANNs) in such a way that each ANN corresponds to a particular neuroanatomic component of the prefrontal circuit which is likely to take part in the execution of the Stroop task. The ability of the proposed model to simulate the normal and the abnormal performance on the Stroop task is tested. The simulation results show that the model is consistent with the clinical data. (c) 2006 Elsevier B.V. All rights reserved

Discrimination ability of the Short Test of Mental Status (STMS) compared to the Mini Mental State Examination (MMSE) in the spectrum of normal cognition, mild cognitive impairment, and probable Alzheimer's disease dementia: The Turkish standardization study

Background: The aim of the present study was to standardize the Short Test of Mental Status (STMS) in the general Turkish aging population and to find its discriminative ability along the continuum of normal cognition, mild cognitive impairment (MCI), and probable Alzheimer's disease dementia (probable AD). Method: The sample was composed of 161 participants older than 50, of which 56 were cognitively normal (CN), 42 had MCI, and 63 had probable AD. STMS, Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR), and Geriatric Depression Scale (GDS) were administered. Results: The mean STMS score in healthy participants was 33.44. With a cutoff score of 32, STMS had a sensitivity of 81% and specificity of 74% to detect participants with MCI, whereas the MMSE did not have an optimal cutoff score to detect MCI. With a cutoff score of 24, STMS had a sensitivity of 88% and specificity of 86% to detect participants with dementia. With a cutoff score of 24, MMSE had a good sensitivity (92%) and specificity (84%), as well. STMS significantly and positively correlated with MMSE, and significantly but inversely correlated with CDR. Reliability of the STMS was good (alpha coef?cient =.88). Conclusion: The results show that STMS is more sensitive than MMSE and can be used by clinicians to differentiate both normal cognition from MCI and MCI from probable AD

SPONTANEOUS DISSECTION OF THE EXTRACRANIAL VERTEBRAL ARTERY WITH SPINAL SUBARACHNOID HEMORRHAGE IN A PATIENT WITH BEHCETS-DISEASE

A 40-year-old man with known definite Behcet's disease (BD) was admitted with confusional state which had started 4 days before admission with an acute headache and vomiting. Neurological examination revealed confusion, stiff neck, right facial weakness, left hemiparesis, dysartria and truncal ataxia. CSF was haemorrhagic and xanthochromic. Cranial CT scans were negative, but MRI showed a right pontine hyperintense lesion on T2-weighted images. Bilateral carotid angiograms were normal. Right vertebral angiogram showed findings consistent with a dissection at the V2 segment of the artery. At the level of the fifth cervical vertebra, a radiculomedullary branch of the vertebral artery with an aneurysmal dilatation in its intradural portion was notable. This case shows that, in BD, aneurysm formation can also occur in a spinal artery and spontaneous vertebral artery dissection can be seen