Search results for "Function"

Ocular tilt reaction: a clinical sign of cerebellar infarctions?

2009

Ocular tilt reaction (OTR) consists of head tilt, ocular torsion (OT), and skew deviation (SKD) combined with perceptual tilts such as deviations of the subjective visual vertical (SVV). Few case reports have shown that OTR also occurs in patients with cerebellar infarctions.1–4 However, no systematic clinical studies are available on the frequency of signs of OTR in patients with cerebellar lesions. Therefore, the questions arose as to whether OTR is a common clinical sign of an acute cerebellar lesion and whether the time course of its components is similar to those from brainstem infarctions. The cerebellar structures involved in 31 patients were studied in detail elsewhere.5 ### Methods…

Impaired cognitive control in patients with brain tumors

2021

Though the assessment of cognitive functions is proven to be a reliable prognostic indicator in patients with brain tumors, some of these functions, such as cognitive control, are still rarely investigated. The objective of this study was to examine proactive and reactive control functions in patients with focal brain tumors and to identify lesioned brain areas more at "risk" for developing impairment of these functions. To this end, a group of twenty-two patients, candidate to surgery, were tested with an AX-CPT task and a Stroop task, along with a clinical neuropsychological assessment, and their performance was compared to that of a well-matched healthy control group. Although overall ac…

Bipolar disorder: A neural network perspective on a disorder of emotion and motivation

2013

Bipolar disorder (BD) is a severe, chronic disease with a heritability of 60-80%. BD is frequently misdiagnosed due to phenomenological overlap with other psychopathologies, an important issue that calls for the identification of biological and psychological vulnerability and disease markers. Altered structural and functional connectivity, mainly between limbic and prefrontal brain areas, have been proposed to underlie emotional and motivational dysregulation in BD and might represent relevant vulnerability and disease markers. In the present laboratory review we discuss functional and structural neuroimaging findings on emotional and motivational dysregulation from our research group in BD…

Testing different ICA algorithms and connectivity analyses on MS patients.

2015

Multiple sclerosis (MS) is a progressive neurological disorder that affects the central nervous system. Functional magnetic resonance imaging (fMRI) has been employed to track the course and disease progression in patients with MS. The two main aims of this study were to apply in a data-driven approach the independent component analysis (ICA) in the spatial domain to depict the active sources and to look at the effective connectivity between the identified spatial sources. Several ICA algorithms have been proposed for fMRI data analysis. In this study, we aimed to test two well characterized algorithms, namely, the fast ICA and the complex infomax algorithms, followed by two effective conne…

Basic operations in working memory: contributions from functional imaging studies.

2010

Abstract Working memory (WM) constitutes a fundamental aspect of human cognition. It refers to the ability to keep information active for further use, while allowing it to be prioritized, modified and protected from interference. Much research has addressed the storage function of WM, however, its ‘working’ aspect still remains underspecified. Many operations that work on the contents of WM do not appear specific to WM. The present review focuses on those operations that we consider “basic” because they operate in the service of memory itself, by providing its basic functionality of retaining information active, in a stable yet flexible way. Based on current process models of WM we review f…

Expectation of sensory stimulation modulates brain activation during visual motion stimulation.

2005

The differential effects of visual hemifield motion stimulation during fixation of a stationary target were compared under two conditions: fixation straight ahead without any further instructions and fixation straight ahead with attention shifted to the "dark hemifield." Data from nine right-handed volunteers revealed that striate and extrastriate right hemispheric visual areas exhibited larger activations during left hemifield motion stimulation when attention was shifted to the right dark hemifield. Montreal Neurological Institute (MNI) coordinates (26, -98, -4) of the additional clusters activated in the latter condition corresponded best to the kinetic occipital region, which is known t…

Adaptive Function and Brain Evolution

2012

Comparing brains is not a mere intellectual exercise but also helps to understand how the brain enables adaptive behavioral strategies to cope with an ever-changing world and how this complex organ has evolved during the phylogeny. For instance, comparative neurobiology helps understanding the specific features of our species, an issue that attracted scientists since the time of Santiago Ramon y Cajal. Following this tradition, 20 years ago Hans ten Donkelaar and Gerhard Roth started the European Conferences on Comparative Neurobiology (ECCN). This e-book includes some of the contributions to the last meeting, the sixth ECCN (Valencia, Spain; April 22-24 2010), plus selected works by severa…

Assessment of Functional Connectome in End-Stage Organ Disease Patients After Life-Threatening Surgery

2020

Purpose The purpose of this study was to assess the organization of intrinsic functional brain networks (functional connectome) in neurologically asymptomatic patients with end-stage organ disease who had undergone major surgery for life-threating conditions and compare it to a control group. Materials and Methods Resting-state functional magnetic resonance imaging (rest-fMRI) was performed in 10 adult, post-operative patients with end-stage organ disease. The patients (7 men, 3 women, mean age 57.9 ± 7.4 years) had undergone: n=4 coronary artery bypass graft for heart failure, n=2 orthotopic liver transplantation for non-alcoholic cirrhotic liver failure, n=3 mitral valve repair for heart …

2015

The recombinant form of tissue plasminogen activator (rt-PA) is the only curative treatment for ischemic stroke. Recently, t-PA has been linked to the metabolism of brain-derived neurotrophic factor (BDNF), a major neurotrophin involved in post-stroke neuroplasticity. Thus, the objective of our study was to investigate the impact of rt-PA treatment on post-stroke circulating BDNF levels in humans and in animals. Serum BDNF levels and t-PA/plasmin activity were measured at hospital admission and at up to 90 days in stroke patients receiving (n = 24) or not (n = 14) rt-PA perfusion. We investigated the relationships between serum BDNF with concurrent t-PA/plasmin activity, neurological outcom…

Robust current observer design for DC-DC converters

2014

In recent years several fast response controllers have been proposed for DC-DC converters. The majority of them rely on a cascade control structure involving the inductor's current in the control function as its faster dynamics, respect to output voltage, allows a significant increase in the regulation performance; the drawback is the need of a proper and expensive current sensor. In this paper a simple and robust formulation for the design of a current observer, based on the output voltage measurement is presented. The formulation is common for the three standard DC-DC converters and the resulting observer is robust to load variation. The observers have been tested in a cascade PI control …