Arousal threshold in the cat as a function of sleep phase and stimulus significance

Résumé Chez le Chat éveillé après conditionnement au moyen de clicks et de lait, les clicks déclenchent le réveil de manière plus efficace qu'en l'absence de conditionnement. Le seuil d'éveil s'est avéré plus bas lors d'un sommeil accompagné d'ondes lentes de haut voltage que pendant le sommeil paradoxal.

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Supported by NSF Grant No. GB 1965.     

Some responses of the superior colliculus of the cat and their control by the visual cortex

Résumé A la stimulation périphérique on enregistre dans le colliculus supérieur du chat anesthésié au chloralose, trois types de réponses: réponse à la lumière, réponses somesthésiques et acoustiques de courte latence et réponses somesthésiques et acoustiques de longue latence. Les résponses somesthésiques et acoustiques de longue latence sont sous le contrôle du cortex visuel tandis que les réponses somesthésiques et acoustiques de courte latence ne dépendent pas de cette région corticale. La réponse à la lumière semble correspondre à une décharge complexe, comprenant l'activation de deux systèmes: un système direct rétino-colliculaire et un système indirect rétino-cortico-colliculaire.     

Arousal as a cyclic phenomenon during sleep and hibernation in the Hedgehog (Erinaceus europeanus)

Résumé L'étude des états de vigilance chez le hérisson (E. europeanus) à la température centrale de 34°C et de 13°C montre que la durée du cycle de sommeil (17,0±3,7 mn) durant l'été est très proche de celle du cycle d'éveil (18,9±1,1 mn) pendant l'hiver. Cette analogie est en faveur du caractère purement endogène d'un tel rythme.

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Supported by grant from the Ministère de l'Agriculture (DGEER).     

Arousal deficit shown in aged rat's quantitative EEG and ameliorative action of pramiracetam compared to piracetam

The basal EEG profile of the aged Fisher-344 rat was consistently different from that of the young rat, showing dominant high voltage slow-wave components. These slow waves were present in both the frontal cerebral cortex and dorsal hippocampus. Absent or greatly attenuated in the aged rat's hippocampal EEG was rhythmic theta activity, which was always dominant in the young awake rat's hippocampus. These EEG differences were clearly apparent only under basal test conditions, i.e., following habituation to the test situation. Pramiracetam sulfate acted strongly to normalize the aged rat's EEG, while the action of piracetam was weak and appeared to undergo tolerance development.     

Arousal deficit shown in aged rat's quantitative EEG and ameliorative action of pramiracetam compared to piracetam

Summary The basal EEG profile of the aged Fisher-344 rat was consistently different from that of the young rat, showing dominant high voltage slow-wave components. These slow waves were present in both the frontal cerebral cortex and dorsal hippocampus. Absent or greatly attenuated in the aged rat's hippocampal EEG was rhythmic theta activity, which was always dominant in the young awake rat's hippocampus. These EEG differences were clearly apparent only under basal test conditions, i.e, following habituation to the test situation. Pramiracetam sulfate acted strongly to normalize the aged rat's EEG, while the action of piracetam was weak and appeared to undergo tolerance development.     

Bradykinin,kallidin, and their synthetic analogues

Zusammenfassung Biochemie und Pharmakologie der drei natürlich vorkommenden und in der Struktur bekannten Kinine — Bradykinin, Kallidin und Methionyl-Lysyl-Bradykinin — sowie deren Synthesen werden besprochen. Für die bisher bekannten 70 Analoga des Bradykinins und Kallidins wurden die biologischen Eigenschaften (Rattenuterus, Meerschweinchenileum, Kaninchenblutdruck, Meerschweinchenblutdruck, Rattenblutdruck, Bronchokonstriktoraktivität) tabellarisch zusammengestellt. Die einzelnen Analoga werden untereinander verglichen und Beziehungen zwischen Struktur und Wirksamkeit diskutiert.     

Models, scientific realism, the intelligibility of nature, and their cultural significance

In this article, I will view realist and non-realist accounts of scientific models within the larger context of the cultural significance of scientific knowledge. I begin by looking at the historical context and origins of the problem of scientific realism, and claim that it is originally of cultural and not only philosophical, significance. The cultural significance of debates on the epistemological status of scientific models is then related to the question of ‘intelligibility’ and how science, through models, can give us knowledge of the world by presenting us with an ‘intelligible account/picture of the world’, thus fulfilling its cultural-epistemic role. Realists typically assert that science can perform this role, while non-realists deny this. The various strategies adopted by realists and non-realists in making good their respective claims, is then traced to their cultural motivations. Finally I discuss the cultural implications of adopting realist or non-realist views of models through a discussion of the views of Rorty, Gellner, Van Fraassen and Clifford Hooker on the cultural significance of scientific knowledge.     

Transcallosal,extracallosal, and geniculo-cortical responses during physiological sleep and wakefulness

Riassunto La TCR è ampia nel sonno (lento e rapido) e ridotta nella veglia. La ECR è massima nel sonno lento e minima nella veglia e sonno profondo. La RCV, minima nel sonno leggero, raggiunge i valori massimi nel sonno desincronizzato. La curva d'interazione tra stimolo transcalloso e genicolato ha rivelato un processo inibitorio prolungato presente soltanto nel sonno leggero.      

Evoked responses and neuronal activity in the lateral geniculate

Résumé Il a paru intéressant de préciser les relations de temps et de phase entre la réponse évoquée massive et la réponse des neurones du corps genouillé latéral. Des microéléctrodes ont été implantées dans le corps genouillé latéral du chat et des réponses ont été évoquées par stimulation visuelle. On a pu démontrer que la probabilité aussi bien que la fréquence de la décharge neuronique varient en raison de la première dérivée de la réponse massive à ondes lentes.

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Aided by grants Nos. NB 07145 and FO5 TW 1017 from the National Institutes of Health.     

Baroreceptor and sympathetic responses to acebutolol, a beta 1-adrenoceptor-blocking agent, in rabbits.

Baroreceptor activity was increased after i.v. infusion of acebutolol in rabbits with an intact circulation, and in rabbits with a total cardiopulmonary by-pass. In rabbits with an intact circulation, renal nerve activity was reduced.     

Magnetic and photic responses in snails

Zusammenfassung Das Ausmass, in dem sich die SchneckeNassarius obsoleta asymmetrischem Licht zuwendet, ist einer früher beschriebenen Orientierungsreaktion übergeordnet, die selbst bei symmetrischer Beleuchtung eintritt. Ausserdem lässt diese Lichtreaktion eine physiologische Asymmetrie erkennen, die durch ein schwaches magnetisches Feld geändert werden kann.

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This study was aided by a grant from the National Science Foundation, No. G-15008, and by a contract between the Office of Naval Research, Department of Navy, and Northwestern University No. 1228-03.     

Adrenal responses to hypoxia and hypercapnia in the young calf

Summary Quantitative analysis of adrenal responses to moderate hypoxia and hypercapnia in the conscious calf shows that the sensitivity of the adrenal cortical response far exceeds that of the adrenal medulla.Acknowledgment. This work has been supported by grants from the Agricultural Research Council, the Medical Research Council and the Wellcome Trust. We are also indebted to Dr D. M. Burley (CIBA) for his continued support.