Simone Cardoso de Oliveira

SCIEDO

Based on psychophysical evidence about how learning of visuomotor transformation generalizes, it has been suggested that movements are planned on the basis of movement direction and magnitude, i.e., the vector connecting movement origin and targets. This notion is also known under the term "vectorial planning hypothesis". Previous psychophysical st...

Based on psychophysical evidence about how learning of visuomotor transformation generalizes, it has been suggested that movements are planned on the basis of movement direction and magnitude, i.e. the vector connecting movement origin and targets. This notion is also known under the term “vectorial planning hypothesis”. Previous psychophysical stu...

Based on psychophysical evidence about how learning of visuomotor transformation generalizes, it has been suggested that movements are planned on the basis of movement direction and magnitude, i.e. the vector connecting movement origin and targets. This notion is also known under the term “vectorial planning hypothesis”. Previous psychophysical stu...

The National Bernstein Network Computational Neuroscience is a funding initiative of the German Federal Ministry of Education and Research (BMBF). It aims at understanding the brain's function through the interdisciplinary approach of Computational Neuroscience. In a joint collaborative effort, biologists, physicians, psychologists, physicists, mat...

Recent studies showed that the low-frequency component of local field potentials (LFPs) in monkey motor cortex carries information about parameters of voluntary arm movements. Here, we studied how different signal components of the LFP in the time and frequency domains are modulated during center-out arm movements. Analysis of LFPs in the time doma...

To what extent does visual feedback shape the coordination between our arms? As a first step towards answering this question, this study compares bimanual coupling in simultaneous bimanual reversal movements that control cursor movements on a vertical screen. While both cursors were visible in the control condition, visual feedback was prevented in...

Franz Mechsner (2004) suggests that movements are exclusively controlled with respect to the effects that they cause in the external world and that motor control can be reduced to prediction of movement effects. Although predictive mechanisms certainly deserve a lot more attention than they have received in the past, the author argues here that pre...

Simultaneous movements of the two arms constitute a relatively simple example of complex movements and may serve to test whether and how the brain generates unique representations of complex movements from their constituent elements, as suggested by Leyton and Sherrington: “[T]he motor cortex may be regarded as a synthetic organ for compounding mov...

Cortical field potentials have been used for decades in neurophysiological studies to probe spatio-temporal activity patterns of local populations of neurons. Recently, however, interest in these signals was spurred as they were proposed as potential control signals for neuronal motor prostheses, i.e., for devices fit to record and decode brain act...

Neuronal activity in primates has been used to address two different questions. The first is what part, or parts of the brain mediate bimanual coordination. The second is how the activity of different parts of the brain is coordinated to achieve bimanual coordination. The answers to both questions are preliminary, but we outline the evidence for a...

The spiking of neuronal populations in motor cortex provides accurate information about movement parameters. Here we show that hand movement target and velocity can be inferred from multiple local field potentials (LFPs) in single trials approximately as efficiently as from multiple single-unit activity (SUA) recorded from the same electrodes. Our...

The spatial organization of tuning properties of neurons in the primate motor cortex is still unknown. Here, we analyze the directional tuning of neurons and local field potentials recorded in the motor cortex of monkeys performing center out arm movements. We found that the tuning of nearby neurons, and of single neurons and local field potentials...

Interactions between bimanual movements may occur at two different levels: at a visually based level, where movement trajectories are programmed within the visually perceived external space, and at the executional level, through crosstalk of sensorimotor signals arising during movement execution. In order to distinguish between these sources of int...

This study investigates the timing of bimanual movements in a combined behavioral and physiological approach. Human subjects and rhesus monkeys performed the same bimanual task. In monkeys, we simultaneously recorded neuronal activity in the two hemispheres of primary motor cortex (MI) or supplementary motor area (SMA), and related it to bimanual c...

Recent physiological studies of the neuronal processes underlying bimanual movements provide new tests for earlier functional models of bimanual coordination. The recently acquired data address three conceptual areas: the generalized motor program (GMP), intermanual crosstalk and dynamic systems models. To varying degrees, each of these concepts ha...

Previous studies have shown that activity of neuronal populations in the primary motor cortex (MI), processed by the population vector method, faithfully predicts upcoming movements. In our previous studies we found that single neurons responded differently during movements of one arm vs. combined movements of the two arms. It was, therefore, not c...

Cortico-cortical connections through the corpus callosum are a major candidate for mediating bimanual coordination. However, aside from the deficits observed after lesioning this connection, little positive evidence indicates its function in bimanual tasks. In order to address this issue, we simultaneously recorded neuronal activity at multiple sit...

We recorded local field potentials (LFP) in primary (MI) and supplementary (SMA) motor areas of rhesus monkey cortex in order to compare movement-evoked potentials (mEP) in bimanual and unimanual movements with single-unit activity recorded concurrently. The mEP was often different during bimanual and unimanual movements (a "bimanual-related" effec...

Research into neural mechanisms of bimanual coordination sheds light on questions raised by psychophysics. While the results we review are merely suggestive, the overall structure of the neural mechanisms may be emerging slowly.Different mechanisms may serve the spatial and temporal coupling of bimanual movements. Temporal coupling depends on a lat...

The dorsal pathway of the primate brain, especially the middle temporal area (MT or V5) and the superior middle temporal area (MST or V5a), is strongly involved in motion detection. The relation between neural firing rates and psychophysical performance has led to the assumption that the neural code used by these areas consists of the relative disc...

Die Frage nach der Funktion des Gehirns, nach dem Verständnis der kognitiven Leistungen des Menschen wird heute nicht selten als das letzte große Geheimnis wissenschaftlicher Forschung bezeichnet. Dieses Geheimnis zu lüften, ist seit den 60er Jahren zum Anliegen interdisziplinärer Forschungen unter dem Schlagwort „Kognitionswissenschaft“ geworden.

In this study, the formation of the corticotectal projection of the rat in organotypic slice culture was investigated, using both anatomical and physiological approaches. The establishment of fibre connections from visual cortex to superior colliculus explants was monitored after 3, 6, 14, 20 and 30 days in vitro by cortical injections of Dil. As i...

We have investigated the presence and function of glia cells, especially of oligodendrocytes (OL) in organotypic cultures of rat visual cortex grown for 1-6 weeks in vitro. OL identified by strong Galactocerebroside-immunoreactivity (GalC-ir) displayed rather small somata and elaborately ramified processes. They were most concentrated in layers VIa...

To study the morphology of neurons in the superior colliculus (SC) and visual cortex (VC) in vitro, the retro- and anterograde tracers biocytin and horseradish-peroxidase (HRP) were applied in cortical and tectal explant co-cultures. Injection of biocytin alone into the SC explant after up to 12 days in vitro revealed the detailed morphology of ret...

To study the mechanisms involved in the formation of neural projections we established an in-vitro model system, consisting of the projection from visual cortex (VC) to colliculus superior (SC) in organotypic slice culture. The typical laminar structure of both brain areas was well conserved in-vitro. A projection from VC to SC was reliably formed....

Basic properties of responses to visual stimulation with large moving random dot patterns were studied in ferret nucleus of the optic tract. Retinal input to NOT was assessed by orthodromic electrical stimulation of the optic chiasm and optic nerves. Presence of an input from visual cortex was tested by orthodromic electrical stimulation of ipsilat...

Effects of early monocular deprivation on visual response properties of neurons in the nucleus of the optic tract (NOT) were studied in six adult ferrets. Retinal input to NOT was investigated by orthodromic electrical stimulation of optic chiasm and optic nerves. Electrical stimulation of the ipsilateral primary visual cortex was applied to reveal...