RESUMEN
OBJECTIVE: Previous studies have linked the choline (Cho) resonance seen in proton magnetic resonance spectroscopy (1H-MRS) to major depressive disorder (MDD). We endeavoured to clarify the possible involvement of cytosolic choline in the amygdala (anterior medial temporal region) of juvenile subjects with MDD. METHOD: A total of 11 age- and sex-matched MDD and control pairs aged 14 to 18 years participated in long-echo proton magnetic resonance spectroscopic imaging (1H-MRSI) of the amygdala. Compounds available include N-acetyl-aspartate (NAA), creatine-phosphocreatine (Cr) and choline-containing compounds. RESULTS: Subjects with depression demonstrated lower left amygdala Cho-Cr ratios, compared with control subjects (paired t = 2.624, df 10, P = 0.025). Left amygdala NAA-Cr and right amygdala Cho-Cr and NAA-Cr did not differ significantly between subjects with depression and control subjects. In subjects with depression, simple regression revealed a negative trend between left amygdala Cho-Cr and Beck Depression Inventory (BDI) score (F = 3.509, P = 0.098). Right amygdala NAA-Cr and Cho-Cr did not differ significantly. CONCLUSION: Cytosolic choline appears to be involved in the pathophysiology of early-onset MDD, likely secondary to corticosteroid-neuroendocrine-driven changes.
Asunto(s)
Amígdala del Cerebelo/fisiopatología , Ácido Aspártico/análogos & derivados , Colina/metabolismo , Citosol/fisiología , Trastorno Depresivo Mayor/diagnóstico , Dominancia Cerebral/fisiología , Espectroscopía de Resonancia Magnética , Adolescente , Ácido Aspártico/metabolismo , Creatina/metabolismo , Trastorno Depresivo Mayor/fisiopatología , Femenino , Humanos , Masculino , Inventario de Personalidad , Valores de ReferenciaRESUMEN
Twenty-four 8-10-year-old children (13 very low birthweight, 11 control) performed a lexical decision and a semantic classification task while event-related potentials (ERPs) were recorded. Both groups were within normal range on standardized reading tests, but the very-low-birthweight group had lower scores. There were no differences between groups in reaction times or accuracy for ERP tasks. On analyses of P2a (246 ms anteriorly), P2p (336 ms posteriorly), N2a (356 ms anteriorly), and N2p (396 ms posteriorly) peaks and a late positive component, control children showed greater right than left asymmetry at P2p and greater left than right asymmetry at N2a. Very-low-birthweight children showed less asymmetry. For the late positive component, both groups showed greater left than right asymmetry, which was more marked for the semantic classification task. The results suggest that very-low-birthweight children display differing cortical utilization during reading.
Asunto(s)
Dislexia/fisiopatología , Dislexia/psicología , Recién Nacido de muy Bajo Peso/fisiología , Recién Nacido de muy Bajo Peso/psicología , Niño , Escolaridad , Potenciales Evocados/fisiología , Femenino , Lateralidad Funcional/fisiología , Humanos , Recién Nacido , Masculino , Pruebas Neuropsicológicas , Desempeño Psicomotor , Tiempo de Reacción , Lectura , VocabularioRESUMEN
The mismatch negativity (MMN) was measured in 15 normal awake 8-month-old infants and 10 adults to the speech consonants /da/ and /ta/. ERPs were analyzed at 11 electrodes (Fz, Cz, Pz, C3, C4, T3, T4, T5, T6, P3, P4). Four-hundred trials were presented: the /da/ standards with 80% probability and the /ta/ deviants with 20% probability. The ISI was 600 ms. An MMN was observed for both adults and infants but with different scalp distributions. A clear infant MMN was observed only at C3 and T3 electrodes, whereas the adult MMN was present at Fz, Cz, C3, C4 and Pz. A repeated-measures ANOVA on the normalized summed area between 200 and 250 ms revealed an age (adult vs. infant) x electrode interaction. Paired t-tests indicated that adults and infants showed significant differences at the C3, Cz, T3, Pz and T6 electrodes. The adult MMN was largest at Cz and C3 whereas the infant MMN was largest at T3. These data are discussed in terms of possible maturational changes in the MMN.
Asunto(s)
Potenciales Evocados Auditivos/fisiología , Habla , Adulto , Conducta , Electroencefalografía , Femenino , Humanos , Lactante , Masculino , Psicología InfantilRESUMEN
The purpose of the experiments reported was to examine how novel, three-dimensional shapes are represented in long-term memory and how this might be differentially affected by monocular and binocular viewing. Three experiments were conducted. The first experiment established that slide projections of the novel objects could be recognized readily if seen in the same orientation as seen during learning. The second and third experiments examined generalization to novel depth rotations of the objects. The second experiment used slide projections of the objects. The results indicated that the representation of the objects seen during training was quite viewpoint-specific as recognition of objects in novel orientations was relatively poor. In the third experiment subjects were shown the real objects under monocular or binocular viewing. Overall, the results are consistent with a growing body of recent research showing that, at least under certain conditions, the visual system stores viewpoint-specific representations of objects.