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The theoretical basis of current source-density (CSD) analysis in the central nervous system is described. Equations relating CSD, the current flow vector, and the extracellular field potential are given. It is shown that the CSD provides superior resolution of neuronal events when compared to conventional field-potential analysis. Expressions for the CSD(More)
This paper represents a systematic, semirigorous attempt to optimize the technique of current source-density (CSD) analysis experimentally. We compared different spatial differentiation formulas in terms of accuracy, aliasing, and smoothing, and provide experimental and theoretical rationale for their use. Sources of error have also been investigated.(More)
Growth cones are specialized structures that form the distal tips of growing axons. During both normal development of the nervous system and regeneration of injured nerves, growth cones are essential for elongation and guidance of growing axons. Developmental and regenerative axon growth is frequently accompanied by elevated synthesis of a protein(More)
A major obstacle to understanding the function and development of the vertebrate brain is the difficulty in monitoring dynamic patterns of electrical activity in the millesecond time domain; this has limited investigations of such phenomena as modular organization of functional units, seizure activities and spreading depression. The use of voltage-sensitive(More)
GAP-43 is one of a small subset of cellular proteins selectively transported by a neuron to its terminals. Its enrichment in growth cones and its increased levels in developing or regenerating neurons suggest that it has an important role in neurite growth. A complementary DNA (cDNA) that encodes rat GAP-43 has been isolated to study its structural(More)
This study examines the effect of applied d.c. electric fields on nerve regeneration following injury to the rat sciatic nerve using the circularly vibrating probe and electron microscopy. The transected and treated nerve which received a d.c. electrical stimulator (0.6 mu A) was compared with untreated transected and crushed nerves. At one week(More)
Several studies have shown that nerve fibers grow preferentially toward the cathode when placed in an electrical field. To study the effects of electrical stimulation on in vivo nerve regeneration, an inexpensive implantable current source has been developed which is able to reliably deliver a minute DC current (0.57 microA) via wick electrodes. The current(More)
Alligator Purkinje cells generate action potentials in the peripheral dendritic tree, after synaptic depolarization via superficial parallel fibers. These action potentials are inhibited at the dendrite level by preceding parallel-fiber volleys at close intervals. We conclude that this inhibition is produced by the activation of the inhibitory interneurons(More)