[Required changes to G-DRG-system 2006 for gastroenterology and hepatology].
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Diagnosis-Related Groups↗
Biomedical subjects
T Roesch
Publications and source records attributed to T Roesch.
Telencephalic bill projections in the Landes goose.
Electrical activity of trigeminal central projection areas was recorded in anesthetized and chronic awake geese. Evoked potentials of telencephalic structures were studied after stimulation of the bill, quintofrontal tract (QF), and several telencephalic structures (nucleus basalis [Bas], neostriatum frontale [NF], paleostriatum augmentatum [PA], and neostriatum caudale [NC]). Short-latency evoked potentials were recorded in Bas after stimulation of the bill or QF; this finding is consistent with a direct connection between the main sensory trigeminal nucleus and Bas. Short- and long-latency evoked potentials were recorded in PA and NC after stimulation of the posterior QF. These potentials are concluded to be due to two different pathways: The shorter-latency response is produced by fibers leaving QF posteriorly, while the longer-latency response is derived from fibers traveling along QF, relaying first in Bas and then in NF. From Bas and NF, two pathways convey impulses to NC; only one is relayed in PA.
Afferent Pathways↗
Lateral hypothalamic relations with medial hypothalamus and limbic areas in geese.
Spontaneous unit activity was recorded in the posteromedial hypothalamic (PMH) and preventricular magnocellular (PVM) nuclei, septal area (S) and hippocampal formation (Hp). Modifications of cellular firing induced by lateral hypothalamic area (LHA) stimulation were examined. Both thiopental anaesthetized and chronic non anaesthetized geese were used. Thiopental appeared to significantly decrease the spontaneous discharge frequency of PMH neurons, and to block both orthodromic and antidromic activations elicited by LHA stimulation. The results indicated that LHA has a predominantly inhibitory influence on PMH as well as on PVM and septal area. The study of antidromic evoked responses in the four areas investigated (PMH, PVM, S, Hp) demonstrated that these structures in turn exert a feed-back control onto LHA. These results are compared with previous electrophysiological, anatomical and behavioral feeding data and an attempt is made to establish some comparisons between birds and mammals.
Animals↗
A goose head holder device for chronic experiments.
A special device is described which allows experiments to be performed on chronic non-anaesthetized geese. This system is composed of two elements: one is fixed to the stereotaxic apparatus, the other is implanted on the goose skull. The use of ear bars and eye and bill pieces is thus eliminated. This non-painful adaptation is well tolerated by the bird. In addition, the position of the animal with regard to stereotaxic coordinates is unchanged. This technique provides an essential tool for furthering investigations on the central nervous system in geese.
Animals↗
A single-unit analysis of reciprocal relationships between the lateral and medial hypothalamus in rats.
The spontaneous activity of hypothalamic units was studied in chronic awake and ketamine-anesthetized rats. Ketamine appeared to decrease significantly the spontaneous firing of neurons in the ventromedial hypothalamic nucleus (VMH) but did not influence the activity in either the dorsomedial hypothalamic nucleus (DMH) or the lateral hypothalamic area (LHA). The responses obtained in the medial hypothalamus and the LHA after stimulation of the LHA and VMH, respectively, were not modified in either of the recording conditions. These responses corresponded to a pause in spontaneous activity, sometimes associated with a short-latency excitatory response, orthodromic or antidromic. The possibility of direct reciprocal connections between the LHA and the VMH has been discussed on the basis of electrophysiological and anatomical studies.
Anesthesia, General↗
Central localisation of somatic evoked responses in Landes goose.
The central localisation of responses to stimulation of different peripheral somatic areas was studied in anaesthetised geese of the Landes breed. Natural (light touch, tap) and electrical stimuli were applied. In the first experiments the changes in the spontaneous activity following natural stimuli were recorded systematically from different brain regions. In the following experiments evoked potentials were recorded from responsive sites. The majority of the somatic responses were localised in the paleostriatum augmentatum, the neostriatum and the neostriatum caudale. Stimulation of the bill and the head elicited responses in tractus quinto-frontalis, paleostriatum augmentatum, neostriatum and neostriatum caudale while activation from the body were mainly localised in neostriatum caudale and paleostriatum augmentatum. Responses to photic stimulation were recorded from the visual wulst, the stratum opticum and the nucleus rotundus. Auditory stimuli were found to be ineffective under our recording conditions. These results are discussed and compared with previous data obtained in other species.
Animals↗