Acquisition of mental state language in Spanish children: a longitudinal study of the relationship between the production of mental verbs and linguistic development.

The development of language indicating the emergence of thinking about the thoughts of self and others has been scarcely studied in Spanish-speaking children. For this reason, we studied the development of mental state language and various indicators of language development in 25 Spanish-speaking children assessed at 3, 3 1/2, 4, 4 1/2, and 5 years of age. We coded and categorized the 40,250 utterances children produced during the five time points, 1202 (3.

Fractal dimension and white matter changes in multiple sclerosis.

The brain white matter (WM) in multiple sclerosis (MS) suffers visible and non-visible (normal-appearing WM (NAWM)) changes in conventional magnetic resonance (MR) images. The fractal dimension (FD) is a quantitative parameter that characterizes the morphometric variability of a complex object. Our aim was to assess the usefulness of FD analysis in the measurement of WM abnormalities in conventional MR images in patients with MS, particularly to detect NAWM changes.

Neuroimaging as a marker of the onset and progression of Alzheimer's disease.

Several neuroimaging techniques are promising tools as early markers of brain pathology in Alzheimer's disease (AD). On structural MRI, atrophy of the entorhinal cortex is present already in mild cognitive impairment (MCI). In the autosomal dominant forms of AD, the rate of atrophy of medial temporal structures separates affected from control persons even 3 years before the clinical onset of cognitive impairment.

Human cerebral activation during steady-state visual-evoked responses.

Flicker stimuli of variable frequency (2-90 Hz) elicit a steady-state visual-evoked response (SSVER) in the electroencephalogram (EEG) with the same frequency as the stimulus. In humans, the amplitude of this response peaks at approximately 15 Hz, decreasing at higher stimulation frequencies. It was not known whether this peak response corresponds to increased synaptic activity in the visual cortex or to other mechanisms [for instance, the temporal coherence (phase summation) of evoked responses].

Activation of human cerebral and cerebellar cortex by auditory stimulation at 40 Hz.

We used functional brain imaging with positron emission tomography (PET)-H2 15O to study a remarkable neurophysiological finding in the normal brain. Auditory stimulation at various frequencies in the gamma range elicits a steady-state scalp electroencephalographic (EEG) response that peaks in amplitude at 40 Hz, with smaller amplitudes at lower and higher stimulation frequencies. We confirmed this finding in 28 healthy subjects, each studied with monaural trains of stimuli at 12 different stimulation rates (12, 20, 30, 32, 35, 37.