ISSN:0006-8977    

DOI:10.1159/000118853

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Starting from a functional-anatomical analysis of the feeding apparatus of a bird, some expectations are formulated regarding the organization of the neuronal systems controlling the activity of this feeding apparatus. The organization of the pre-motor-motor system of the jaw muscles, of the exteroceptive system conveying tactile sense from tongue and beak to the brain and of the proprioceptive system of the jaw muscles is discussed. An attempt is made to relate specific structural features of these systems to their function in the control of the different feeding patterns of birds.

ISSN:0006-8977    

DOI:10.1159/000118854

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Data on the interaction between respiration, coughing, feeding, vision and oculomotor control in fish have been analyzed. A self-contained respiratory rhythm generator in the brainstem reticular formation is, at times, interrupted by a coughing generator, which is partly autorhythmic and partly under vagal afferent control. A number of cranial muscles are shared by the respiratory and masticatory systems. Others are predominately allocated to one of these systems but are recruited by the other under heavy loading conditions. The effect of retinal image displacements caused by respiration-induced eye movements appears to be centrally corrected during normal respiration. In addition, excessive eye movements are reduced by extraocular muscle contraction during intense respiration and cough. Both the central visual and the oculomotor corrections are based on open-loop control through input from the respiratory center.

ISSN:0006-8977    

DOI:10.1159/000118855

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Swallowing is a complex motor sequence involving the coordinated contraction of several muscles in the mouth, pharynx, larynx and esophagus. The motor sequence of swallowing, which can be entirely performed without afferent feedback, is centrally programmed by a neuronal network. This network can be divided into three levels: (i) an afferent level corresponding to the input arm to the network, that is mainly the solitary tract; (ii) an efferent level corresponding to the output arm of the network, that is the different pools of motoneurons involved in swallowing and localized within the trigeminal and hypoglossal nuclei and the nucleus ambiguus; (iii) an organizing level corresponding to the interneuronal network which programs the swallowing motor sequence. The ''swallowing interneurons'' of the organizing level are localized in two medullary regions: (i) a dorsal region including the nucleus of the solitary tract (NST) and the adjacent reticular formation, and (ii) a ventral region corresponding to the lateral reticular formation above the nucleus ambiguus. Neurons localized within the NST region are interneurons which largely go to make up the part of the network which initiates and programs swallowing. Originating from these neurons, the central swallowing command is relayed by the interneurons within the ventrolateral reticular formation before reaching the different groups of motoneurons which excite the swallowing reactions.

ISSN:0006-8977    

DOI:10.1159/000118856

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Licking behavior of rats appeared to be interrupted periodically for about 20 ms. Behavioral and electrophysiological evidence is presented which indicates that during this period swallowing occurs. The hypothesis was tested that swallowing initiation depends on the volume of water that has accumulated in the oral cavity during drinking. No support for this hypothesis was obtained when the flow rate of water through the drinking tube was manipulated. Alternative hypotheses are discussed.

ISSN:0006-8977    

DOI:10.1159/000118857

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Specific excitatory and inhibitory influences on protrusive (P) and retrusive motoneurons in the hypoglossal nucleus of cat have been documented. Stimuli delivered to peripheral branches of the auriculotemporal nerve which innervate the temporomandibular joint activate both genioglossus (GG) single units and synaptically-evoked responses in P motoneurons. Similarly, stimuli delivered to the glossopharyngeal (IX) and superior laryngeal nerves activate P motoneurons. Any one of these three stimuli may contribute to the various responses in which the GG muscle is known to participate. In contrast, stimuli applied to the tongue itself (lingual and IX nerves) result in a retrusive tongue movement. These brainstem mechanisms suggest specific therapy regimens for the treatment of skeletal open-bite malocclusions where resting tongue posture appears to be a primary etiological factor.

ISSN:0006-8977    

DOI:10.1159/000118858

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Reflex activity was induced in the digastric and other submandibular muscles of pre-weaning rats, rabbits, cats and guinea pigs by electrical stimulation of the mouth. At birth, rats, cats and rabbits had long-latency reflexes which shortened with maturation. In the rat and rabbit, adult values are reached a day or so before they are known to ingest solid food. Only the guinea pig, which eats solids on day 1, had the adult latency at birth. The time course of the latency reduction in the rabbit appeared to have two phases. The first phase was rapid (1–2 days) and appeared to be largely of central origin. The second phase was slower and lasted for about 2 week

ISSN:0006-8977    

DOI:10.1159/000118859

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

This paper reports on experiments on the jaw opening reflex carried out while awake unrestrained cats were eating or walking on a treadmill. It is shown that the jaw opening reflex response to low intensity stimulation diminished in all phases of the masticatory cycle. The response to higher threshold afferents, however, is phase modulated so that the largest responses occur during the jaw closing phase. This is in accord with the need for increased protection of the soft tissues in this phase of the movement. In contrast, the digastric reflex amplitude does not change when the cat passes from quiet standing to walking on the treadmill. Evidence is presented that the electromyographic activity of the jaw closing muscles increases during upwards movement of the head during walking and decreases as the head falls. These data support the hypothesis that the myotatic reflex in the elevator muscles plays a role in stabilizing the mandible during locomotion.

ISSN:0006-8977    

DOI:10.1159/000118860

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

Electrical stimulation of low threshold, fast afferents in the inferior alveolar nerve produce very short latency synaptic field potentials in the cerebellar cortex anterior lobe typical of mossy fibre inputs. The afferents concerned are from periodontal receptors, some of which project directly without relay. Muscle afferents do not show this direct projection. The functional significance of this arrangement is discussed, bearing in mind the parallel with the direct projection of some first order vestibular afferents. It is suggested that the specialisation seen may be the basis for sensory calibration of spindle inputs by means of periodontal afferents.

ISSN:0006-8977    

DOI:10.1159/000118861

出版商:S. Karger AG    

年代:1984

数据来源: Karger

摘要:

In rats anesthetized with ketamine, effects of jaw jerks (rise time 5 ms, strength 70 mN) applied in the open direction were studied both in the quiescent preparation and during rhythmic jaw-opening and jaw-closing movements (induced by mechanical stimulation of the palate). The left masseter, posterior and anterior digastric and omohyoid muscles were fitted with electrodes for recording electromyographic responses. In the quiescent state a jaw jerk causes responses in all recorded muscles. In the rhythmic preparation masseter responses persisted but digastric and omohyoidal responses were suppressed. This suppression was most prominent when jerks were applied during closing. However, responses in digastrics and omohyoid persisted when masseter nerves and periodontal afferents of the lower incisors were blocked with xylocaine. The suppression of digastric and omohyoidal responses therefore originates – at least partly – from masseter and periodontal afferents. When the periodontal afferents alone were blocked with xylocaine only the response in the opening phase persisted. The suppression of digastric and omohyoidal responses during opening are therefore reflexes from periodontal receptors. These observations support the concept that oral activity is controlled by two relatively independent systems. The first program-oriented system generates the basic movements whereas the second, environment-oriented, system has access to the program for correcting perturbations. There is evidence that muscles poorly supplied with muscle spindles (digastrics and omohyoid) act as pure effectors. Modulation of their activity is prompted by exteroceptors and muscle receptors in the masticatory musc

ISSN:0006-8977    

DOI:10.1159/000118862

出版商:S. Karger AG    

年代:1984

数据来源: Karger