5-HT2AR and BDNF gene variants in eating disorders susceptibility.

Evidence from family and twin studies points to a genetic contribution to the etiology of eating disorders (EDs), confirmed by the association of several single nucleotide polymorphisms (SNPs) with this group of disorders. Previous reports have suggested that the serotonin receptor (5-HT2AR) and brain-derived neurotrophic factor (BDNF) genes could be both involved in EDs susceptibility. In order to provide further evidence about such association, we focused our attention on two SNPs located in these genes carrying out a genetic association study on a large Italian cohort composed of 556 ED patients and 355 controls (CTRs). Obtained results confirm the presence of an association between 5-HT2AR and BDNF genes and the susceptibility to EDs.

Hypertonic saline is more effective than normal saline in seasonal allergic rhinitis in children.

Allergic rhinitis (AR) is a very common childhood disease that is associated with a significant reduction in the patients' quality of life. Its treatment combines educating the patients and their parents, immunotherapy and drug administration. However, even the best approach does not relieve the symptoms of a number of patients. Alternative therapies are particularly needed for children because the fear of adverse events frequently reduces parental compliance to the prescribed drugs, and immunotherapy is less easy to administer than in adults. In this prospective investigator-blinded study we evaluated whether children, with a documented history of seasonal grass pollen-related AR, benefit from nasal irrigation by assessing the effects on nasal signs and symptoms, on middle ear effusion and on adenoidal hypertrophy. We randomized children aged 5 to 9 years (median age 82 months) to normal saline or hypertonic saline (a 2.7% sodium chloride solution), administered twice-daily using a disposable 20 ml syringe, or no treatment. Nasal symptoms (rhinorrhea, itching, sneezing, nasal obstruction), swelling of turbinates, adenoid hypertrophy or middle ear effusion were assessed at baseline and after 4 weeks of treatment. Two hundred and twenty children (normal saline: 80; hypertonic saline: 80; no treatment: 60) completed the study. After four weeks, all the considered items were significantly reduced in the group receiving hypertonic saline (P < 0.0001), whereas in the group receiving normal saline only rhinorrhea (P = 0.0002) and sneezing (P = 0.002) were significantly reduced. There was no significant change in any of the items in the control group. The duration of oral antihistamines was significantly lower in the children receiving hypertonic saline than in those treated with normal saline or in controls. No adverse events were reported and parental satisfaction and compliance with the procedure were globally very good, regardless of the solution used. Using our procedure, hypertonic saline is effective, inexpensive, safe, well tolerated and easily accepted by children with seasonal grass pollen-related AR and their parents. Our data suggest that nasal irrigation with hypertonic saline might be included in the wide spectrum of therapies recommended for grass-pollen AR.

Human v6: the medial motion area.

Cortical-surface-based functional Magnetic Resonance Imaging mapping techniques and wide-field retinotopic stimulation were used to verify the presence of pattern motion sensitivity in human area V6. Area V6 is highly selective for coherently moving fields of dots, both at individual and group levels and even with a visual stimulus of standard size. This stimulus is a functional localizer for V6. The wide retinotopic stimuli used here also revealed a retinotopic map in the middle temporal cortex (area MT/V5) surrounded by several polar-angle maps that resemble the mosaic of small areas found around macaque MT/V5. Our results suggest that the MT complex (MT+) may be specialized for the analysis of motion signals, whereas area V6 may be more involved in distinguishing object and self-motion.

Spatial re-orienting of visual attention along the horizontal or the vertical axis.

Neuroimaging data indicate functional segregation between voluntary and stimulus-driven control of spatial attention in dorsal and ventral fronto-parietal regions, respectively. While recent evidences demonstrated location-specific attentional effects in dorsal regions, little is known about any location or direction selectivity within the ventral network. Here, we used a spatial cueing paradigm to investigate stimulus-driven spatial re-orienting along different axes (horizontal or vertical). We found that re-orienting of attention activated the ventral attentional network, irrespective of axis-orientation. Statistical comparisons between homologous regions in the two hemispheres revealed significant main effects of attention re-orienting (common activation for the two hemispheres), irrespective of leftward or rightward re-orienting along the horizontal axis, or re-orienting along the vertical axis. We conclude that in healthy volunteers, a bilateral ventral network controls spatial covert re-orienting, and that this system is multidirectional.

Evaluation of mixed effects in event-related fMRI studies: impact of first-level design and filtering.

With the introduction of event-related designs in fMRI, it has become crucial to optimize design efficiency and temporal filtering to detect activations at the 1st level with high sensitivity. We investigate the relevance of these issues for fMRI population studies, that is, 2nd-level analysis, for a set of event-related fMRI (er-fMRI) designs with different 1st-level efficiencies, adopting three distinct 1st-level filtering strategies as implemented in SPM99, SPM2, and FSL3.0. By theory, experiments, and simulations using physiological fMRI noise, we show that both design and filtering impact the outcome of the statistical analysis, not only at the 1st but also at the 2nd level. There are several reasons behind this finding. First, sensitivity is affected by both design and filtering, since the scan-to-scan variance, that is the fixed effect, is not negligible with respect to the between-subject variance, that is the random effect, in er-fMRI population studies. The impact of the fixed effects error on the sensitivity of the mixed effects analysis can be mitigated by an optimal choice of er-fMRI design and filtering. Moreover, the accuracy of the 1st- and 2nd-level parameter estimates also depend on design and filtering; especially, we show that inaccuracies caused by the presence of residual noise autocorrelations can be constrained by designs that have hemodynamic responses with a Gaussian distribution. In conclusion, designs with both good efficiency and decorrelating properties, for example, such as the geometric or Latin square probability distributions, combined with the "whitening" filters of SPM2 and FSL3.0, give the best result, both for 1st- and 2nd-level analysis of er-fMRI studies.

Improved detection of event-related functional MRI signals using probability functions.

Selecting an optimal event distribution for experimental use in event-related fMRI studies can require the generation of large numbers of event sequences with characteristics hard to control. The use of known probability distributions offers the possibility to control event timing and constrain the search space for finding optimal event sequences. We investigated different probability distributions in terms of response estimation (estimation efficiency), detectability (detection power, parameter estimation efficiency, sensitivity to true positives), and false-positive activation. Numerous simulated event sequences were generated selecting interevent intervals (IEI) from the uniform, uniform permuted, Latin square, exponential, binomial, Poisson, chi(2), geometric, and bimodal probability distributions and fixed IEI. Event sequences from the bimodal distribution, like block designs, had the best performance for detection and the poorest for estimation, while high estimation and detectability occurred for the long-decay exponential distribution. The uniform distribution also yielded high estimation efficiency, but probability functions with a long tail toward higher IEI, such as the geometric and the chi(2) distributions, had superior detectability. The distributions with the best detection performance also had a relatively high incidence of false positives, in contrast to the ordered distributions (Latin square and uniform permuted). The predictions of improved sensitivities for distributions with long tails were confirmed with empirical data. Moreover, the Latin square design yielded detection of activated voxels similar to the chi(2) distribution. These results indicate that high detection and suitable behavioral designs have compatibility for application of functional MRI methods to experiments requiring complex designs.

Psychophysical properties of line bisection and body midline perception in unilateral neglect.

Past research associated unilateral neglect with a systematic ipsilesional shift of the perceived position of the body midline; however, this was not confirmed by recent experiments. We used the constant stimuli method to control for potential artifacts intrinsic to the techniques used in previous studies. Body midline perception was measured in the visual and proprioceptive modalities in ten patients with left unilateral neglect, ten control patients and ten normal subjects and compared with a visual line bisection task, also using the constant stimuli method. Neglect patients showed a significant rightward bias in the line bisection task, but no consistent directional bias either in the proprioceptive or in the visual body midline task. These results clearly counter the association between neglect and an ipsilesional shift of the body midline. However, in the body midline tasks neglect patients made more errors in judgement on both sides of their subjective midline, both with respect to the control groups and with respect to the line bisection task. This may imply that a specific impairment of body-centered representations is indeed present and manifests as a non directional increase in response variability, rather than as a systematic shift. It is suggested that body- and object-related tasks (such as line bisection) may be processed by independent cognitive computations. This interpretation is discussed with reference to a recent neuroimaging study investigating the same kinds of tasks.