The nucleus retroambiguus control of respiration

The role of the nucleus retroambiguus (NRA) in the context of respiration control has been subject of debate for considerable time. To solve this problem, we chemically (using d, L-homocysteic acid) stimulated the NRA in unanesthetized precollicularly decerebrated cats and studied the respiratory effect via simultaneous measurement of tracheal pressure and electromyograms of diaphragm, internal intercostal (IIC), cricothyroid (CT), and external oblique abdominal (EO) muscles, NRA-stimulation 0-1 mm caudal to the obex resulted in recruitment of IIC muscle and reduction in respiratory frequency. NRA-stimulation 1-3 mm caudal to the obex produced vocalization along with CT activation and slight increase in tracheal pressure, but no change in respiratory frequency. NRA-stimulation 3-5 mm caudal to the obex produced CT muscle activation and an increase in respiratory frequency, but no vocalization. NRA-stimulation 5-8 mm caudal to the obex produced EO muscle activation and reduction in respiratory frequency. A change to the inspiratory effort was never observed, regardless of which NRA part was stimulated. The results demonstrate that NRA does not control eupneic inspiration but consists of topographically separate groups of premotor interneurons each producing detailed motor actions. These motor activities have in common that they require changes to eupneic breathing. Different combination of activation of these premotor neurons determines the final outcome, e.g., vocalization, vomiting, coughing, sneezing, mating posture, or child delivery. Higher brainstem regions such as the midbrain periaqueductal gray (PAG) decides which combination of NRA neurons are excited. In simple terms, the NRA is the piano, the PAG one of the piano players

Emotions Studied by Imaging of the Human Brain:The Somatic and Emotional Motor Systems

The brain has only two goals, survival of the individual and survival of the species. One of the most important tools to accomplish these goals is the motor system, which includes the somatic or voluntary motor system and the emotional motor system (EMS). The EMS is equally or even more important than the somatic motor system. In humans, the cortex cerebri with the corticospinal tract plays the most important role in the somatic motor system, while in the EMS, the periaqueductal gray (PAG) plays a central role controlling nociception, cardiovascular changes, respiration, micturition, parturition, defecation, vocalization, vomiting, coughing, sneezing, mating behavior, pupil dilation, and defensive posture.</p

Survival of the individual, survival of the species

contribution à la pré-conférence au 34e congrès LIBER qui s\u27est tenu à le Bibliothèque universitaire de Groningue aux Pays-Bas du 5 au 9 juillet 2005

Descending motor pathways and the spinal motor system. Limbic and non-limbic components

For a thorough understanding of the descending pathways of the motor system originating in the forebrain, knowledge about the anatomy and function of the structures in the more caudally located parts of the central nervous system is indispensable. In this paper an overview will be presented\ud of these caudal structures in brainstem and spinal cord as far as they concern the motor system, (sections 1 to 3). After that the descending pathways belonging to the so-called somatic motor system are reviewed (section 4). Finally, a summary of the many newly discovered pathways related to the limbic system will be given (section 5). In the Conclusions section a concept will be presented, which subdivides the multitude of motor pathways into three motor systems. In this concept the motoneurons will be considered to belong to the peripheral motor system, (motor unit, which is the motoneuronal cell body-motor axon-muscle). The first motor system consists of the interneurons involved in motor reflex pathways. The second motor system contains the pathways of the so-called somatic motor system, while the third motor system comprises the motor pathways related to the limbic system. The second and third motor systems act upon the neurons of the first motor system and to a limited extent directly on motoneurons, but not on each other. The importance and strength of the third motor system, which, untill recendy, was virtually unknown, will be emphasize

Converging and dissolving the University Library : pré-conférence au 34e congrès LIBER (2005)

Pré-conférence au 34e congrès LIBER qui s\u27est tenu à le Bibliothèque universitaire de Groningue aux Pays-Bas du 5 au 9 juillet 2005. Réflexions sur le devenir les bibliothèques universitaires à l\u27âge des TIC et des grands vecteurs privés d\u27information (Google, Amazon, etc.)

Functional sex differences in human primary auditory cortex

Background We used PET to study cortical activation during auditory stimulation and found sex differences in the human primary auditory cortex (PAC). Regional cerebral blood flow (rCBF) was measured in 10 male and 10 female volunteers while listening to sounds (music or white noise) and during a baseline (no auditory stimulation). Results and discussion We found a sex difference in activation of the left and right PAC when comparing music to noise. The PAC was more activated by music than by noise in both men and women. But this difference between the two stimuli was significantly higher in men than in women. To investigate whether this difference could be attributed to either music or noise, we compared both stimuli with the baseline and revealed that noise gave a significantly higher activation in the female PAC than in the male PAC. Moreover, the male group showed a deactivation in the right prefrontal cortex when comparing noise to the baseline, which was not present in the female group. Interestingly, the auditory and prefrontal regions are anatomically and functionally linked and the prefrontal cortex is known to be engaged in auditory tasks that involve sustained or selective auditory attention. Thus we hypothesize that differences in attention result in a different deactivation of the right prefrontal cortex, which in turn modulates the activation of the PAC and thus explains the sex differences found in the activation of the PAC. Conclusion Our results suggest that sex is an important factor in auditory brain studies