Learn More
Optical imaging of voltage-sensitive dyes in an isolated cerebellum preparation was used to study the spatiotemporal functional organization of the inhibitory systems in the cerebellar cortex. Responses to surface stimulation of the cortex reveal two physiologically distinct inhibitory systems, which we refer to as lateral and on-beam inhibition following(More)
The discrepancy between the structural longitudinal organization of the parallel-fiber system in the cerebellar cortex and the functional mosaic-like organization of the cortex has provoked controversial theories about the flow of information in the cerebellum. We address this issue by characterizing the spatiotemporal organization of neuronal activity in(More)
The chemokine CXCL12 is essential for the function of hematopoietic stem and progenitor cells. Here we report that secretion of functional CXCL12 from human bone marrow stromal cells (BMSCs) was a cell contact-dependent event mediated by connexin-43 (Cx43) and Cx45 gap junctions. Inhibition of connexin gap junctions impaired the secretion of CXCL12 and(More)
The large number of diverse functions attributed to the cerebellum appears to be inconsistent with its simple, homogeneous and evolutionary preserved structure. A homogeneous structure that participates in a variety of functions implies that a common denominator underlies all of them. Since the concept of precise timing can be recognized in almost all(More)
Doublecortin (DCX) is a microtubule-associated protein necessary for neuronal migration. In spite of its ubiquitous distribution in dendrites, its possible role in dendrite development has not yet been documented. The present study examined the effects of different expression levels of DCX on the arborization of dendrites in cultured hippocampal neurons.(More)
Synchronized network activity is an essential attribute of the brain. Yet the cellular mechanisms that determine the duration of network bursts are not fully understood. In the present study, synchronized network bursts were evoked by triggering an action potential in a single neuron in otherwise silent microcultures consisting of 4-30 hippocampal neurons.(More)
An experimental system that combines optical imaging of voltage-sensitive dyes with an in vitro isolated cerebellum preparation is described. The optical imaging system is based on a photodiode array and two rather simple amplification stages. The isolated cerebellum preparation preserves the integrity of the neuronal circuitry, thus allowing the(More)
Spontaneous synchronized bursts of activity play an essential role in the maturation and plasticity of neuronal networks. To investigate the cellular properties that enable spontaneous network activity, we used dissociated cultures of hippocampal neurons that express prolonged network activity bursts. Acute exposure to a low concentration of(More)
Neuronal networks can generate complex patterns of activity that depend on membrane properties of individual neurons as well as on functional synapses. To decipher the impact of synaptic properties and connectivity on neuronal network behavior, we investigate the responses of neuronal ensembles from small (5-30 cells in a restricted sphere) and large (acute(More)