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D A Poulos

Publications and source records attributed to D A Poulos.

11 recordsLinked to original sources
PubMed1979

Efferent projections from temperature sensitive recording loci within the marginal zone of the nucleus caudalis of the spinal trigeminal complex in the cat.

The efferent projections from nucleus caudalis of the spinal trigeminal complex in cats were studied with retrograde and anterograde axonal transport techniques combined with localization of recording sites in the thalamus and marginal zone of nucleus caudalis to innocuous skin cooling. Results showed brainstem projections from nucleus caudalis to rostral levels of the spinal trigeminal complex, to the ventral division of the principal trigeminal nucleus, the parabrachial nucleus, cranial motor nuclei 7 and 12, solitary complex, contralateral dorsal inferior olivary nucleus, portions of the lateral reticular formation, upper cervical spinal dorsal horn and, lateral cervical nucleus. Projections to the thalamus included; a dorsomedial region of VPM (bilaterally) and to the main part of VPM and PO contralaterally. Neuronal activity was recorded in the dorsomedial region of VPM to cooling the ipsilateral tongue. HRP injections in this thalamic region retrogradely labeled marginal neurons in nucleus caudalis. These results show that marginal neurons of nucleus caudalis provide a trigeminal equivalent of spinothalamic projections to the ventroposterior nucleus in cats.

Animals↗
PubMed1979

Analysis and measurement of some sources of variability in experimental spinal cord trauma.

Experiments were performed on anesthetized cats to determine whether the variability that is common in experimental spinal cord injuries produced by the weight-drop technique can be reduced if a more accurate determination of the actual intensity of the insult to the cord is measured. In addition, determinations of the contribution of such variables as mass of drop-weight, impounder diameter, and animal weight to variability were made. It was found that of the three measures of intensity readily available from a strain gauge transducer, impulse (change in momentum of drop-weight) showed the highest correlation with the histologically determined extent of the lesion. It was shown that the mass of the drop-weight had a significant effect on lesion size even when the gram X centimeter quantification of the injury was constant. Animal weight and impounder diameter did not make a significant contribution to the variability of injury as determined by low-power microscopy.

Acceleration↗
PubMed1978

Evaluation of experimental spinal cord injury by measuring spontaneous spinal cord potentials.

The relationship between the spontaneous spinal electrogram and the degree of spinal cord injury was studied in anesthetic-free, surgically decerebrate cats that received experimental blunt trauma by the graded weight-drop method. It was found that the characteristic spontaneous slow negative potential of the spinal electrogram showed a frequency dependency that correlated positively with the intensity of the injury (impulse expressed in gm-sec). Graphs of the frequency of occurrence of the slow negative potentials as a function of time following initial injury indicated that both the slope and shape of the curve were dependent on the severity of the injury measured in gm-sec at the time of the injury and confirmed histologically. These results indicate that the spontaneous spinal electrogram may serve as a sensitive indicator of the degree of spinal cord injury and may be useful in the assessment of various treatment modalities.

Animals↗