D C Gordon

Learn More
1. "Unmasking" of weak synaptic connections has been suggested as a mechanism for the early changes in cortical topographic maps that follow alterations of sensory activity. For such a mechanism to operate, convergent sensory inputs must already exist in the normal cortex. 2. We tested for topographic and cross-modality convergence in primary somatosensory(More)
A combination of retrograde tracing methods was employed to distinguish populations of motoneurons supplying different motor unit territories in the feline diaphragm. The compatibility of the tracers--horseradish peroxidase, fast or true blue, diamidino yellow, and fluorogold--was first assessed by applying the different tracers concurrently to separate cut(More)
Sartorius (SART) and tensor fasciae latae (TFL) in the cat hindlimb are functionally heterogeneous muscles with regions that differ in their skeletal actions and electromyographic recruitment during normal activity. The topographical organization of motoneurons supplying different regions of SART or TFL has been investigated by exposing cut nerve branches(More)
Multiple labelling methods were used to examine the topographical organization of motoneurons supplying the suboccipital muscles, rectus capitis posterior (RCP) and obliquus capitis inferior (OCI); the intervertebral muscles, spinalis dorsi (SD) and semispinalis cervicis (SSC); and the dorsal extensor biventer cervicis (BC). Muscle nerves were isolated,(More)
1. Reorganizations of representational maps have been described for a variety of sensory and motor regions of cerebral neocortex in several species. The purpose of this study was to investigate synaptic mechanisms of the reorganizations of primary somatosensory cortex that follow removal of a digit or the joining of two digits into a syndactyly. We examined(More)
We have recorded auditory evoked potentials, of both neurogenic and myogenic origin, in cats having neonatal high frequency cochlear hearing loss. Using frequency specific stimuli (tone pips) and by measuring responses near to threshold, we have probed tonotopic (or cochleotopic) representation within the brainstem-midbrain auditory pathway. At stimulus(More)
Recent studies have demonstrated that, under certain circumstances, the diaphragm does not contract as a homogeneous unit. These observations suggest that motor units may not be randomly distributed throughout the muscle but confined to localized subvolumes. In the present study, electromyographic (EMG) and glycogen depletion methods were combined to(More)
Previous anatomical descriptions of the diaphragm have contained several contradictory findings. To validate and extend the previous work, diaphragmatic architecture, histochemistry, and end-plate distribution were examined by use of a combination of anatomical methods, including fiber microdissections, cholinesterase staining, and enzyme histochemistry.(More)
  • 1