Categoría: Papers con abstracts

Objective: Several longitudinal studies had shown that early deprivation and institutionalization during the first six months of life affects the emotional, cognitive, social and neurophysiologic development. Nevertheless, our understanding of possible similar effects of delayed institutionalization, in preschool-age remains unclear to this day. The goal of this study is to evaluate the cognitive performance of institutionalized children with history of preschool-age physical abandonment. Method: 18 male institutionalized children with history of abandonment during the preschool-age (2-5 years old) and comparison group matched by age, handedness, gender, educational and socioeconomic level were tested on multiple tasks of attention, memory and executive functions. Results: We found a cognitive impairment in the institutionalized children in several measures of attention, memory and executive functions. This is the first report of cognitive impairment related to late abandonment and institutionalization effects (after 2 years old), extending the already known effects on early institutionalization. Conclusions: This preliminary study suggests that environmental factors including abandonment and institutional care, can affect not only the infancy period, but also the preschool period providing new insights into our understanding of neurocognitive development.

Objective: To investigate the presence of dysfunctional cognitions in adults with ADHD and to determine whether these cognitions are associated with emotional symptoms, maladaptive coping, and functional impairment, as predicted by the cognitive-behavioral model. Method: A total of 35 adult participants with ADHD, 20 nonclinical controls, and 20 non-ADHD clinical controls were assessed with measures of ADHD symptoms, dysfunctional cognitions, depression and anxiety symptoms, coping strategies, and quality of life. Results: ADHD group showed elevated scores of dysfunctional cognitions relative to nonclinical control group and comparable with clinical control group. Dysfunctional cognitions were strongly associated with emotional symptoms. ADHD group also showed elevated scores in maladaptive coping strategies of the escape-avoidance type. Life impairment was satisfactorily predicted in data analysis when ADHD symptoms, dysfunctional cognitions, and emotional symptoms were fitted into a regression model. Conclusion: Cognitive-behavioral therapy model appears to be a valid complementary model for understanding emotional and life impairment in adults with ADHD.

Only a small proportion of individuals with Mild Cognitive Impairment (MCI) will convert to dementia. Methods currently available to identify risk for conversion do not combine enough sensitivity and specificity, which is even more problematic in low-educated populations. Current guidelines suggest the use of combined markers for dementia to enhance the prediction accuracy of assessment methods. The present study adhered to this proposal and investigated the sensitivity and specificity of the electrophysiological component P300 and standard neuropsychological tests to assess patients with Alzheimer´s disease (AD) and MCI recruited from a low-income country. The neuropsychological battery comprised tests of memory, attention, language, praxis and executive functions. The P300 was recorded using a classical visual odd-ball paradigm. Three variables were found to achieve sensitivity and specificity values above 80% (Immediate and Delayed recall of word list – CERAD – and the latency of P300) for both MCI and AD. When they entered the model together (i.e., combined approach) the sensitivity for MCI increased to 96% and the specificity remained high (80%). Our preliminary findings suggest that the combined use of sensitive neuropsychological tasks and the analysis of the P300 may offer a very useful method for the preclinical assessment of AD, particularly in populations with low socioeconomic and educational levels. Our results provide a platform and justification to employ more resources to convert P300 and related parameters into a biological marker for AD.

Paraquat is one of the most widely used herbicides worldwide. It produces a Parkinson´s disease (PD) model in rodents through redox cycling and oxidative stress (OS) and is associated with PD risk in humans. Glutathione transferases provide cellular protection against OS and could potentially modulate paraquat toxicity. We investigated PD risk associated with paraquat use in individuals with homozygous deletions of the genes encoding glutathione S-transferase M1 (GSTM1) or T1 (GSTT1). Eighty-seven PD subjects and 343 matched controls were recruited from the Agricultural Health Study, a study of licensed pesticide applicators and spouses in Iowa and North Carolina. PD was confirmed by in-person examination. Paraquat use and covariates were determined by interview. We genotyped subjects for homozygous deletions of GSTM1 (GSTM1*0) and GSTT1 (GSTT1*0) and tested interaction between paraquat use and genotype using logistic regression. Two hundred and twenty-three (52%) subjects had GSTM1*0, 95 (22%) had GSTT1*0, and 73 (17%; all men) used paraquat. After adjustment for potential confounders, there was no interaction with GSTM1. In contrast, GSTT1 genotype significantly modified the association between paraquat and PD. In men with functional GSTT1, the odds ratio (OR) for association of PD with paraquat use was 1.5 (95% confidence interval [CI]: 0.6–3.6); in men with GSTT1*0, the OR was 11.1 (95% CI: 3.0–44.6; P interaction: 0.027). Although replication is needed, our results suggest that PD risk from paraquat exposure might be particularly high in individuals lacking GSTT1. GSTT1*0 is common and could potentially identify a large subpopulation at high risk of PD from oxidative stressors such as paraquat.

Previous studies have reported facial emotion recognition impairments in schizophrenic patients, as well as abnormalities in the N170 component of the event-related potential. Current research on schizophrenia highlights the importance of complexly-inherited brain-based deficits. In order to examine the N170 markers of face structural and emotional processing, DSM-IV diagnosed schizophrenia probands (n=13), unaffected first-degree relatives from multiplex families (n=13), and control subjects (n=13) matched by age, gender and educational level, performed a categorization task which involved words and faces with positive and negative valence. The N170 component, while present in relatives and control subjects, was reduced in patients, not only for faces, but also for face-word differences, suggesting a deficit in structural processing of stimuli. Control subjects showed N170 modulation according to the valence of facial stimuli. However, this discrimination effect was found to be reduced both in patients and relatives. This is the first report showing N170 valence deficits in relatives. Our results suggest a generalized deficit affecting the structural encoding of faces in patients, as well as the emotion discrimination both in patients and relatives. Finally, these findings lend support to the notion that cortical markers of facial discrimination can be validly considered as vulnerability markers.

Social cognitive neuroscience is a recent interdisciplinary field that studies the neural basis of the social mind. Event-related potentials (ERPs) provide precise information about the time dynamics of the brain. In this study, we assess the role of ERPs in cognitive neuroscience, particularly in the emerging area of social neuroscience. First, we briefly introduce the technique of ERPs. Subsequently, we describe several ERP components (P1, N1, N170, vertex positive potential, early posterior negativity, N2, P2, P3, N400, N400-like, late positive complex, late positive potential, P600, error-related negativity, feedback error-related negativity, contingent negative variation, readiness potential, lateralized readiness potential, motor potential, re-afferent potential) that assess perceptual, cognitive, and motor processing. Then, we introduce ERP studies in social neuroscience on contextual effects on speech, emotional processing, empathy, and decision making. We provide an outline of ERPs’ relevance and applications in the field of social cognitive neuroscience. We also introduce important methodological issues that extend classical ERP research, such as intracranial recordings (iERP) and source location in dense arrays and simultaneous functional magnetic resonance imaging recordings. Further, this review discusses possible caveats of the ERP question assessment on neuroanatomical areas, biophysical origin, and methodological problems, and their relevance to explanatory pluralism and multilevel, contextual, and situated approaches to social neuroscience.

Surface dyslexia has been attributed to an overreliance on the sub-lexical route for reading. Typically, surface dyslexic patients commit regularisation errors when reading irregular words. Also, semantic dementia has often been associated with surface dyslexia, leading to some explanations of the reading impairment that stress the role of semantics in irregular word reading. Nevertheless, some patients have been reported with unimpaired ability to read irregular words, even though they show severe comprehension impairment. We present the case of M.B., the first Spanish-speaking semantic dementia patient to be reported who shows unimpaired reading of non-words, regular words, and – most strikingly – irregular loan words. M.B. has severely impaired comprehension of the same words he reads correctly (whether regular or irregular). We argue that M.B.’s pattern of performance shows that irregular words can be correctly read even with impaired semantic knowledge corresponding to those words.

The diagnostic criteria for the attention deficit/hyperactivity disorder (ADHD) were defined by the American Psychiatric Association in the Diagnostic and Statistical Manual of Mental Disorders, fourth version. ADHD is a neuro-psychiatric disorder associated with impairments in everyday life and behavioral dysregulation (i.e. inattention, hyper-activity and impulsivity), and it has showed empirical evidence from clinical, pharmacological, and psychometric studies. Nevertheless, the role of neurobiological impairments in the presentation of the symptoms remains unclear. For this paper, the authors reviewed Spanish and English literature that support the neurobiological validity of the disorder, aimed to present evidence associated with its cognitive and behavioral phenotype (e.g. in: neuropsychology, electrophysiology, structural and functional magnetic resonance imaging, neurochemistry and genetics). Additionally, an integrative theoretical clinical and scientific proposal is presented. Finally, the introduction of neurobiological marker as part of the definitive diagnosis is suggested, as a started point for the identification of therapeutic targets.

The growing interest for the scientific study of consciousness and the current development of neuroimaging tools have allowed to investigate the neuronal correlates of hypnosis and to expand its scope to assess normal and pathological neurocognitive phenomena. At an empirical level, theories that postulate hypnosis as a neurophysiological distinctive state of consciousness (´state theories´), and theories that claim that hypnosis would just represent different neurophysiological changes associated to specific suggestions without no change in the state of consciousness (´non-state theories´); have both been assessed. In this work, these two theories are critically reviewed, their main features are discussed and their neurophysiological evidence is described. A growing body of evidence supports that a hypnotic state of consciousness involves mainly the anterior cingulated cortex and the dorsolateral frontal cortex; as well as a pattern of attenuated cortical functional connectivity. Also, we concluded that hypnotic suggestions have allowed a better comprehension of a diversity of normal and pathological neuropsychological processes. Finally, we stated that the neurophysiologic evidence until now is still insufficient to solve the debate between state and non-state theorists.

Loss in insight is a major feature of frontotemporal dementia (FTD) but has been investigated relatively little. More importantly, the neural basis of insight loss is still poorly understood. The current study investigated insight deficit profiles across a large cohort of neurodegenerative patients (n = 81), including FTD and Alzheimer’s disease (AD) patients. We employed a novel insight questionnaire, which tapped into changes across different domains: social interaction, emotion, diagnosis/treatment, language, and motivation. FTD subtypes varied considerably for insight loss, with the behavioral variant worst and the progressive non-fluent variant least affected. All other subtypes and AD showed milder but consistent insight loss. Voxel-based morphometry analysis revealed that overall insight loss correlated with ventromedial and frontopolar prefrontal atrophy, with exception of social interaction and emotion insight loss, which additionally correlated with lateral temporal and amygdala atrophy, respectively. Our results show that patients with neurodegenerative conditions show variable loss of insight, with ventromedial and frontopolar cortex regions appearing to be particularly important for insight.