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Abstract: Combined deep brain stimulation of the subthalamic (STN) and pedunculopontine (PPN) nuclei has been recently proposed as surgical treatment of advanced Parkinson''s disease. STN stimulation alone has been shown to provide selective improvement of the grammatical aspect of language. We studied five advanced Parkinson''s disease patients who underwent combined deep brain stimulation (STN + PPN). Overall cognitive profile did not change. On the contrary, an interesting trend towards reduction of ungrammatical errors (particularly substitution of free and inflectional morphemes) was found when stimulating the STN, and also the PPN, when the STN was switched off. These findings replicate previous observations on the STN, and provide the rationale for further investigation of the role of the PPN in processing linguistic grammar. [Copyright &y& Elsevier]

Abstract: Thirteen bilingual patients with Parkinson''s disease and thirteen bilingual healthy controls matched for age, sex, formal education, and cognitive functioning were administered three linguistic tests of sentence comprehension and grammatical judgment in both native Azari (L1) and Farsi (L2) languages. Both groups had acquired L2 late (formal learning at primary school) and presented with mild cognitive impairment. Parkinson''s patients had greater linguistic impairments in L1 than L2, and they had greater L1 and L2 impairments than healthy controls. These findings strongly replicate previous ones (Zanini et al., 2004) and suggest that L1 grammar processing mainly recruits cortical-subcortical language networks in agreement with the Declarative/Procedural model of language acquisition (Paradis, 1994; Ullman, 2001) and that general cognitive functioning ought to be carefully investigated with respect to linguistic impairments in bilingual subjects, especially in the case of adult subjects with neurodegenerative disorders. [Copyright &y& Elsevier]

Abstract: Objective: It has been demonstrated that the early part of 600Hz High Frequency Oscillations (HFOs), probably generated in the terminal part of thalamo-cortical somatosensory radiations, are abnormally reduced between attacks in migraineurs. We aimed at verifying whether spontaneous clinical fluctuations in migraine are correlated to HFO changes. Methods: We recorded somatosensory evoked potentials in 28 migraine patients. Clinical fluctuations (number of attacks in the 6months preceding and following the test) were correlated to the HFOs’ amplitudes. Moreover, eight out of 28 patients underwent a longer follow-up, including HFO control and clinical observation during the 12months following the baseline recording. Results: The amplitude of early presynaptic HFOs was significantly correlated to the clinical evolution, since spontaneous worsening was associated with reduced presynaptic HFOs, whereas spontaneous improvement was associated with enhanced presynaptic HFOs (correlation test, p <0.05). No correlation was found between the amplitude of postsynaptic HFOs and clinical fluctuations. Patients undergoing longer follow-up showed substantially unchanged HFOs, accordingly with their stable clinical condition. Conclusions: HFOs’ enhancement in spontaneously improved patients can reflect the increased activity of brainstem arousal related structures, which in turn increases the thalamo-cortical drive and the cortical lateral inhibition mediated by GABAergic interneurons. Significance: HFOs’ recording could represent a useful tool in the functional assessment of migraine. [Copyright &y& Elsevier]

Abstract: Background: A combined protocol of voxel-based morphometry (VBM) and diffusion-weighted imaging (DWI) was applied to investigate the neurodevelopment of gray and white matter in autism. Methods: Twenty children with autism (mean age=7±2.75 years old; age range: 4–14; 2 girls) and 22 matched normally developing children (mean age=7.68±2.03 years old; age range: 4–11; 2 girls) underwent magnetic resonance imaging (MRI). VBM was employed by applying the Template-o-Matic toolbox (TOM), a new approach which constructs the age-matched customized template for tissue segmentation. Also, the apparent diffusion coefficients (ADC) of water molecules were obtained from the analysis of DWI. Regions of interests (ROIs), standardized at 5 pixels, were placed in cortical lobes and corpus callosum on the non-diffusion weighted echo-planar images (b =0) and were then automatically transferred to the corresponding maps to obtain the ADC values. Results: Compared to normal children, individuals with autism had significantly: (1) increased white matter volumes in the right inferior frontal gyrus, the right fusiform gyrus, the left precentral and supplementary motor area and the left hippocampus, (2) increased gray matter volumes in the inferior temporal gyri bilaterally, the right inferior parietal cortex, the right superior occipital lobe and the left superior parietal lobule, and (3) decreased gray matter volumes in the right inferior frontal gyrus and the left supplementary motor area. Abnormally increased ADC values in the bilateral frontal cortex and in the left side of the genu of the corpus callosum were also reported in autism. Finally, age correlated negatively with lobar and callosal ADC measurements in individuals with autism, but not in children with normal development. Conclusions: These findings suggest cerebral dysconnectivity in the early phases of autism coupled with an altered white matter maturation trajectory during childhood potentially taking place in the frontal and parietal lobes, which may represent a neurodevelopmental marker of the disorder, possibly accounting for the cognitive and social deficits. [Copyright &y& Elsevier]

Abstract: Objective: Amplitude decrease of cortical responses after repeated stimuli (‘habituation’) is a well-known phenomenon, the functional meaning of which is to prevent sensory overflow and to save resources for meaningful and novel stimuli. It is known that the primary low-frequency N20 somatosensory evoked potential (SEP) undergoes habituation in healthy subjects. By contrast, the presence of this phenomenon has never been tested in High Frequency Oscillations (HFOs), which probably reflect the activity of a somatosensory arousal system. Methods: We recorded SEPs after right median nerve stimulation in 19 healthy volunteers. Six consecutive series of 500 sweeps were collected and averaged at a repetition rate of 5Hz. SEPs were recorded by means of Erb’point-to-Fz, Cv6-to-AC and P3-to-F3 arrays. P3-to-F3 recording further underwent narrow-bandpass (400–800Hz) digital filtering to selectively analyse high-frequency components. Results: Statistical analysis revealed a significant amplitude decrease of the primary N20 LF-SEP between the first and sixth block of stimuli. By contrast, HFO amplitudes remained substantially unchanged throughout the whole procedure. Conclusions: Differently from the N20 LF-SEP, scalp-recorded HFOs do not undergo habituation. Significance: Our findings reinforce the view that HFOs reflect the activity of an arousal somatosensory system, which is able to signal novel stimuli, the relevance of which points out high synaptic efficacy. [Copyright &y& Elsevier]