Biomedical subjects

Sossio Cirillo

Publications and source records attributed to Sossio Cirillo.

9 recordsLinked to original sources

PubMed2006

Independent component model of the default-mode brain function: Assessing the impact of active thinking.

The "default-mode" network is an ensemble of cortical regions, which are typically deactivated during demanding cognitive tasks in functional magnetic resonance imaging (fMRI) studies. Using functional connectivity, this network can be conceptualized and studied as a "stand-alone" function or system. Regardless of the task, independent component analysis (ICA) produces a picture of the "default-mode" function even when the subject is performing a simple sensori-motor task or just resting in the scanner. This has boosted the use of default-mode fMRI for non-invasive research in brain disorders. Here, we studied the effect of cognitive load modulation of fMRI responses on the ICA-based pictures of the default-mode function. In a standard graded working memory study based on the n-back task, we used group-level ICA to explore the variability of the default-mode network related to the engagement in the task, in 10 healthy volunteers. The analysis of the default-mode components highlighted similarities and differences in the layout under three different cognitive loads. We found a load-related general increase of deactivation in the cortical network. Nonetheless, a variable recruitment of the cingulate regions was evident, with greater extension of the anterior and lesser extension of the posterior clusters when switching from lower to higher working memory loads. A co-activation of the hippocampus was only found under no working memory load. As a generalization of our results, the variability of the default-mode pattern may link the default-mode system as a whole to cognition and may more directly support use of the ICA model for evaluating cognitive decline in brain disorders.

Adult↗

PubMed2006

Predictors of tumor shrinkage after primary therapy with somatostatin analogs in acromegaly: a prospective study in 99 patients.

CONTEXT: Primary treatment with depot octreotide and lanreotide induces tumor shrinkage in newly diagnosed patients with acromegaly. OBJECTIVE: The objective of the study was to evaluate clinical predictors of tumor shrinkage. DESIGN: This was an analytical, observational, open, prospective study. SUBJECTS: The study included 99 patients: 13 with microadenoma and 86 with macroadenoma (25 enclosed, 32 extrasellar, 29 invasive). MAIN OUTCOME MEASURES: Age, gender, estimated disease duration, body mass index, GH and IGF-I levels, and tumor volume at diagnosis and after 12 months of treatment were measured. Percentage of GH, IGF-I, and tumor size changes from baseline were also analyzed. Tumor changes were scored as absent (+/- 0-25%), mild (+/- 25.1-50%), moderate (+/- 50.1-75%), or notable (75%). INTERVENTIONS: Sixty patients (60.6%) received depot octreotide im (20-30 mg every 28 d), and 39 patients (39.4%) received lanreotide im (60-90 mg every 28 d). RESULTS: Basal tumor volume and maximal tumor diameter correlated with age, disease duration, and GH levels. After 12 months, GH levels were controlled (</=2.5 microg/liter) in 57.6%, IGF-I levels in 45.5%, and both in 42.4%. Shrinkage was absent in 22 patients (22.2%), mild in 31 (31.1%), moderate in 30 (30.3%), and notable in 14 patients (14.1%). Two patients (not responding to treatment) had a mild tumor increase (by 34 and 31.2%, respectively). Basal and posttreatment tumor volumes were highly correlated (r = 0.79, P < 0.0001). At the multistep regression analysis, the percent IGF-I decrease (t = 2.6; P = 0.011) was the best predictor of posttreatment tumor volume, followed by patients' age (t = 2.1; P = 0.042) and percent GH decrease (t = 2.0; P = 0.044). CONCLUSIONS: Most patients with acromegaly (75.5%) had 25% or greater tumor shrinkage after 12 months of primary somatostatin analog therapy: significant increase of tumor mass occurred in only 2.1% of patients (uncontrolled during treatment). Best predictor of tumor shrinkage was posttreatment IGF-I.

Acromegaly↗

PubMed2006

How does spatial extent of fMRI datasets affect independent component analysis decomposition?

Spatial independent component analysis (sICA) of functional magnetic resonance imaging (fMRI) time series can generate meaningful activation maps and associated descriptive signals, which are useful to evaluate datasets of the entire brain or selected portions of it. Besides computational implications, variations in the input dataset combined with the multivariate nature of ICA may lead to different spatial or temporal readouts of brain activation phenomena. By reducing and increasing a volume of interest (VOI), we applied sICA to different datasets from real activation experiments with multislice acquisition and single or multiple sensory-motor task-induced blood oxygenation level-dependent (BOLD) signal sources with different spatial and temporal structure. Using receiver operating characteristics (ROC) methodology for accuracy evaluation and multiple regression analysis as benchmark, we compared sICA decompositions of reduced and increased VOI fMRI time-series containing auditory, motor and hemifield visual activation occurring separately or simultaneously in time. Both approaches yielded valid results; however, the results of the increased VOI approach were spatially more accurate compared to the results of the decreased VOI approach. This is consistent with the capability of sICA to take advantage of extended samples of statistical observations and suggests that sICA is more powerful with extended rather than reduced VOI datasets to delineate brain activity.

Acoustic Stimulation↗

PubMed2003

Differential sex-independent amygdala response to infant crying and laughing in parents versus nonparents.

BACKGROUND: Animal and human studies implicate forebrain neural circuits in maternal behavior. Here, we hypothesized that human brain response to emotional stimuli relevant for social interactions between infants and adults are modulated by sex- and experience-dependent factors. METHODS: We used functional magnetic resonance imaging and examined brain response to infant crying and laughing in mothers and fathers of young children and in women and men without children. RESULTS: Women but not men, independent of their parental status, showed neural deactivation in the anterior cingulate cortex, as indexed by decreased blood oxygenation level-dependent signal, in response to both infant crying and laughing. The response pattern changed fundamentally with parental experience: in the amygdala and interconnected limbic regions, parents (independent of sex) showed stronger activation from crying, whereas nonparents showed stronger activation from laughing. CONCLUSIONS: Our data show sex- and experience-dependent modulation of brain response to infant vocalizations. Successful recognition and evaluation of infant vocalizations can be critical for bonding mechanisms and for offspring well-being and survival. Thus, the modulation of responses by experience seems to represent an adaptive mechanism that can be related to reproductive fitness.

Acoustic Stimulation↗

PubMed2003

fMRI of the auditory system: understanding the neural basis of auditory gestalt.

Functional magnetic resonance imaging (fMRI) has rapidly become the most widely used imaging method for studying brain functions in humans. This is a result of its extreme flexibility of use and of the astonishingly detailed spatial and temporal information it provides. Nevertheless, until very recently, the study of the auditory system has progressed at a considerably slower pace compared to other functional systems. Several factors have limited fMRI research in the auditory field, including some intrinsic features of auditory functional anatomy and some peculiar interactions between fMRI technique and audition. A well known difficulty arises from the high intensity acoustic noise produced by gradient switching in echo-planar imaging (EPI), as well as in other fMRI sequences more similar to conventional MR sequences. The acoustic noise interacts in an unpredictable way with the experimental stimuli both from a perceptual point of view and in the evoked hemodynamics. To overcome this problem, different approaches have been proposed recently that generally require careful tailoring of the experimental design and the fMRI methodology to the specific requirements posed by the auditory research. The novel methodological approaches can make the fMRI exploration of auditory processing much easier and more reliable, and thus may permit filling the gap with other fields of neuroscience research. As a result, some fundamental neural underpinnings of audition are being clarified, and the way sound stimuli are integrated in the auditory gestalt are beginning to be understood.

Auditory Cortex↗

PubMed2003

Real-time independent component analysis of fMRI time-series.

Real-time functional magnetic resonance imaging (fMRI) enables one to monitor a subject's brain activity during an ongoing session. The availability of online information about brain activity is essential for developing and refining interactive fMRI paradigms in research and clinical trials and for neurofeedback applications. Data analysis for real-time fMRI has traditionally been based on hypothesis-driven processing methods. Off-line data analysis, conversely, may be usefully complemented by data-driven approaches, such as independent component analysis (ICA), which can identify brain activity without a priori temporal assumptions on brain activity. However, ICA is commonly considered a time-consuming procedure and thus unsuitable to process the high flux of fMRI data while they are acquired. Here, by specific choices regarding the implementation, we exported the ICA framework and implemented it into real-time fMRI data analysis. We show that, reducing the ICA input to a few points within a time-series in a sliding-window approach, computational times become compatible with real-time settings. Our technique produced accurate dynamic readouts of brain activity as well as a precise spatiotemporal history of quasistationary patterns in the form of cumulative activation maps and time courses. Results from real and simulated motor activation data show comparable performances for the proposed ICA implementation and standard linear regression analysis applied either in a sliding-window or in a cumulative mode. Furthermore, we demonstrate the possibility of monitoring transient or unexpected neural activities and suggest that real-time ICA may provide the fMRI researcher with a better understanding and control of subjects' behaviors and performances.

Algorithms↗

PubMed2003

Efficacy of sequential chemotherapy including methotrexate and doxorubicin in an infant with partially resected choroid plexus carcinoma.

This report refers to a 3-month-old male, with a residual choroid plexus carcinoma following partial resection, who was successfully treated with sequential chemotherapy without any postoperative radiation therapy. Along with carboplatin, we also used doxorubicin and methotrexate, hypothesizing that, given the patient's age, the blood-brain barrier should not hamper drug delivery to the tumor. According to this hypothesis, the treatment achieved complete remission of the disease, which lasts 27 months after the diagnosis. This result deserves further studies to assess the possible curative role of chemotherapy in very young patients suffering from choroid plexus carcinoma.

Antimetabolites, Antineoplastic↗

PubMed2002

Coordinate and categorical judgements in spatial imagery. An fMRI study.

We aimed at verifying whether the hemispheric specialisation for categorical/coordinate spatial judgements also applies to the spatial imagery domain by the use of whole-brain fMRI. In a block-design experiment we used the "coordinate" mental clock test, contrasting it with a "categorical" task applied to the same clock stimuli; as a control task we used a syllable counting task requiring a verbal-phonological judgement on the same material of the two imagery tasks. Our results showed that categorical and coordinate spatial judgements on imagined stimuli rely on the activation of a set of cortical areas, centred upon the superior parietal lobule (SPL) bilaterally. These regions, together with other parietal and prefrontal areas, showed a pattern of relative lateralization, with the left hemisphere being mainly activated during the categorical task and the right in the coordinate task. These data confirm the strong involvement of the SPL in spatial processing. Moreover, our findings suggest that different interconnected neural networks are activated to comply with specific test requirements, giving rise to functional imaging patterns compatible with psychological theories on hemispheric specialization.

Adult↗

PubMed2002

Small hypothalamic hamartomas and gelastic seizures.

PURPOSE: To describe the clinical history of patients with gelastic seizures (GSs) related to small-size hypothalamic hamartomas (HHs), and to show some of these unusual seizures. MATERIAL AND METHODS: Patients with GSs and the MRI finding of HH < 1 cm diameter. Ictal EEG or video EEG are required. RESULTS: Three patients, among 6 with GSs and HH, had a small sessile HH. None of them had a history of precocious puberty, nor any relevant cognitive defects. All patients suffered from other seizure types, in addition to GSs. GSs were drug-resistant in all cases. CONCLUSION: since small, not easily recognizable HHs may be present in patients with GSs, a careful MRI study of the hypothalamic, infundibular and mammillary bodys areas is mandatory in these cases [published with videosequences].

Adult↗