Justin Dye

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1. Weakly electric fish generate around their bodies low-amplitude, AC electric fields which are used both for the detection of objects and intraspecific communication. The types of modulation in this signal of which the high-frequency wave-type gymnotiform, Apteronotus, is capable are relatively few and stereotyped. Chief among these is the chirp, a signal(More)
We have taken advantage of the increasing understanding of glutamate neuropharmacology to probe mechanisms of well-defined vertebrate behaviors. Here we report a set of experiments that suggests distinct roles for two major classes of glutamate receptors in a discrete premotor nucleus of the brainstem. The medullary pacemaker nucleus of weakly electric fish(More)
1. In an in vitro preparation of the medullary pacemaker nucleus of Apteronotus, the consequences of a variety of ionic and pharmacological manipulations upon both ongoing activity and synaptic modulation of the nucleus were assessed. 2. Spontaneous rhythmicity in the pacemaker nucleus was found to be Na+-, K+-, and Ca(2+)-dependent. The extreme sensitivity(More)
1. An in vitro preparation of the medullary pacemaker nucleus of the weakly electric fish Apteronotus leptorhynchus was studied which fires regularly and synchronously at the fish's characteristic frequency of electric organ discharge (EOD). Upon bipolar stimulation of tissue regions through which pass prepacemaker nucleus afferents to the pacemaker, a(More)
We have developed two brain slice preparations for studying tectofugal visual pathways in the chick: conventional, 400-microns slices ("thin slices"), and "thick slices" which encompass the rostral pole of the optic tectum and the contralateral optic nerve. Stimulation was delivered with a bipolar electrode positioned in stratum opticum in thin slices and(More)
1. The weakly electric gymnotiform fish, Apteronotus leptorhynchus, can be induced to perform a variety of modulations of its quasi-sinusoidal, electric organ discharge (EOD) in acute physiological preparations. These modulations, many of which are communicatory in function, include the jamming avoidance response (JAR). We have recorded intracellularly from(More)
BACKGROUND Phase-contrast MRI (PC-MRI) has previously been used for the quantification of CSF and blood flow throughout the body. We propose a new method of semi-automated segmentation for the prepontine cistern based on anatomical and pulsatility information. METHODS Scans were conducted on 48 patients (69.83 ± 14.28 years) ranging in age from 32 to 88(More)
Irregular vestibular afferents exhibit significant phase leads with respect to angular velocity of the head in space. This characteristic and their connectivity with vestibulospinal neurons suggest a functionally important role for these afferents in producing the vestibulo-collic reflex (VCR). A goal of these experiments was to test this hypothesis with(More)
23 Irregular vestibular afferents exhibit significant phase leads with respect to angular velocity of 24 the head in space. This characteristic and their connectivity with vestibulospinal neurons 25 suggest a functionally important role for these afferents in producing the vestibulo-collic 26 reflex (VCR). A goal of these experiments was to test this(More)
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