Alexander B. Pinus

Learn More
Subsystems of category learning have been identified on the basis of general domains of content (e.g., tools, faces). The present study examined categories from the standpoint of internal structure and determined brain topography associated with expressing two fundamentally different category rule structures (criterion attribute, CA, and family resemblance,(More)
This research study addresses the question: does the neural circuit implementing a motor task undergo change as a function of even limited practice? To detect potential neural changes associated with limited practice we compared brain activation at the early and late stages of motor performance on a simple task over one relatively brief session.(More)
OBJECTIVE To study rapidly alternating movements under fMRI in order to identify the brain regions that mediate increased complexity in bimanual vs unimanual movements and to verify the localization of a clinical test of limb ataxia (diadochokinesis). METHODS Unimanual and bimanual movements, that is, palm(s) pronated then supinated, served as stimulation(More)
The purpose of this study was to empirically investigate and compare the effects of alternating and continuous experimental task designs on blood oxygenation level dependent (BOLD) signal contrast. Six healthy volunteers underwent single-finger opposition functional magnetic resonance imaging (fMRI) using T2*-weighted echo planar imaging technique on a 1.5(More)
This study investigates the effect of arousal on visual selection processes. Arousal is predicted to narrow the window of attention surrounding a point of focus. BOLD response to a letter discrimination task was measured under aroused (aversive noise) and non-aroused conditions (n = 8). Results revealed spatially distinct responses for trials invoking a(More)
PURPOSE To prospectively evaluate magnetic resonance (MR) imaging for the characterization of liver fibrosis by estimating fat and extracellular matrix content and hepatic perfusion parameters in CCl(4)-treated rats. MATERIALS AND METHODS The animal research protocol was approved by the Institutional Animal Care and Use Committee. Fifty-two rats (38(More)
BACKGROUND AND PURPOSE In patients with multiple sclerosis (MS), a few preliminary functional MR (fMR) imaging studies of the visual cortex reveal information about magnitude differences between healthy individuals and patients with MS at only a single luminance level. We therefore investigated whether varying luminance contrast levels can help uncover(More)
The functional neuroanatomy of time estimation has not been well-documented. This research investigated the fMRI measured brain response to an explicit, prospective time interval production (TIP) task. The study tested for the presence of brain activity reflecting a primary time keeper function, distinct from the brain systems involved either in conscious(More)
PURPOSE To measure and quantitatively characterize an activity generated by the neurons of the visual cortex (VC) in response to graded luminous intensity contrast stimuli using a 1.5 Tesla scanner. MATERIALS AND METHODS Functional magnetic resonance imaging (fMRI) of the vc with the intrinsic blood oxygenation level dependent (BOLD) mechanism was(More)
Simultaneous electroencephalograph-functional magnetic resonance imaging (EEG-fMRI) recording has become an important tool for investigating spatiotemporal properties of brain events, such as epilepsy, evoked brain responses, and changes in brain rhythms. Reduction of noise in EEG signals during fMRI recording is crucial for acquiring high-quality EEG-fMRI(More)