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PubMed1984

Primitive reflex profile: a quantitation of primitive reflexes in infancy.

This report describes quantitative standardization data on nine primitive reflexes for a cohort of 381 normal infants evaluated longitudinally at each visit between birth and two years of age. Normality was confirmed by the use of the Bayley Scales of Infant Development at one year of age. The standardization of this new examination technique complements the traditional infant neurological examination and may allow primitive reflexes to become a useful adjunct to the prediction of motor disability in early infancy.

Brain Damage, Chronic↗

PubMed1992

Capsaicin-induced bronchoconstriction in the guinea-pig: contribution of vagal cholinergic reflexes, local axon reflexes and their modulation by BW443C81.

1 The objective of the study was to investigate the central vagal and local axon reflex components of bronchoconstrictor responses evoked by inhalation of capsaicin aerosol in anaesthetized guinea-pigs. This was accomplished by comparing the effects of bilateral vagotomy, atropine and the peripherally-acting polar enkephalin analogue, BW443C81, on bronchoconstrictor responses evoked by capsaicin. The effects of codeine were also determined. 2 Aerosols of capsaicin were generated from a 0.9 microgram ml-1 solution. Inhalation of capsaicin aerosol in 5, 10 and 15 breaths evoked dose-related bronchoconstrictor responses. The responses were immediate in onset and of extended duration. 3 Capsaicin-induced bronchoconstrictor responses were significantly inhibited following bilateral vagotomy or atropine (0.3 mg kg-1, i.v.) pretreatment by 46% +/- 14% (P less than 0.05) and 59% +/- 13% (P less than 0.01), respectively. 4 Administration of BW443C81 by intravenous infusion (3, 30 and 100 micrograms kg-1 min-1) caused a significant inhibition of capsaicin-induced bronchoconstrictor responses which achieved a greater maximum than either bilateral vagotomy or atropine. Codeine (100 micrograms kg-1 min-1, i.v.) did not significantly inhibit the bronchoconstrictor responses. 5 Inhibition of capsaicin-induced bronchoconstrictor responses by BW443C81 (30 micrograms kg-1 min-1, i.v.) was significantly (P less than 0.05) reduced by the peripherally-acting opioid antagonist N-methyl nalorphine (100 micrograms kg-1 min-1, i.v.). 6 These results show that capsaicin-induced bronchoconstrictor responses are mediated by at least two mechanisms, a vagal and/or cholinergic reflex pathway and a non-cholinergic pathway. BW443C81, but not codeine, significantly inhibited (P < 0.005) both mechanisms of capsaicin-induced bronchoconstriction probably by an action on peripheral opioid receptors located on vagal sensory nerves.

Amino Acid Sequence↗

PubMed1979

Reflex pathways in the abdominal prevertebral ganglia: evidence for a colo-colonic inhibitory reflex.

1. In vitro experiments were performed on preparations consisting of prevertebral ganglia attached to the entire colon of guinea-pigs. The colon was divided into an orad and a caudad segment and intraluminal pressure was recorded from the terminal end of each segment. Intracellular recordings were simultaneously obtained from neurones in the coeliac plexus. 2. The source of mechanosensory input from the colon paralleled the responses to mesenteric nerve stimulation. That is, section of the mesenteric nerve that contributed the strongest synaptic input to a neurone eliminated most of the mechanosensory input to that neurone. 3. The origin of the mechanosensory input to some neurones could be localized as coming from either the orad or caudad segment of the colon. In the coeliac ganglia 68% of the neurones tested responded primarily to orad distension and 37% to caudad distension. In the superior mesenteric ganglion 57% responded to orad distension and 43% to caudad distension. 4. Repetitive stimulation of the mesenteric nerve trunks arising from the prevertebral ganglia inhibited contractions differentially in the orad and caudad segments. The inferior coeliac nerves inhibited primarily the orad segments of colon and the lumbar colonic nerves inhibited primarily the caudad segments of colon. Stimulation of the superior coeliac nerves did not alter the motility of either segment. 5. When one of the colonic segments was distended, contractions in the other colonic segment were inhibited in 71% of the distensions. This inhibition operated in both directions: either orad inhibiting caudad or vice versa. 6. Cutting the intermesenteric nerve which communicates between the orad and caudad prevertebral ganglia eliminated the inhibitory reflex. 7. These experiments provide evidence for a colo-colonic inhibitory reflex mediated through pathways in the prevertebral ganglia.

Afferent Pathways↗

PubMed1974

Electromyographic and reflex study in idiopathic and symptomatic trigeminal neuralgias: latency of the jaw and blink reflexes.

Recorded jaw reflexes were studied in 51 normal subjects. In addition, the blink and jaw reflexes combined with masseteric electromyography were recorded in 17 unselected patients with facial pain. Six of these patients, including two without neurological anomalies, showed electrodiagnostic anomalies. The method proved valuable for differentiation between idiopathic and symptomatic trigeminal neuralgia.

Adult↗

PubMed2003

Musings on the wanderer: what's new in our understanding of vago-vagal reflexes? III. Activity-dependent plasticity in vago-vagal reflexes controlling the stomach.

Vago-vagal reflex circuits modulate digestive functions from the oral cavity to the transverse colon. Previous articles in this series have described events at the level of the sensory receptors encoding the peripheral stimuli, the transmission of information in the afferent vagus, and the conversion of this data within the dorsal vagal complex (DVC) to impulses in the preganglionic efferents. The control by vagal efferents of the postganglionic neurons impinging on the glands and smooth muscles of the target organs has also been illustrated. Here we focus on some of the mechanisms by which these apparently static reflex circuits can be made quite plastic as a consequence of the action of modulatory inputs from other central nervous system sources. A large body of evidence has shown that the neuronal elements that constitute these brain stem circuits have nonuniform properties and function differently according to status of their target organs and the level of activity in critical modulatory inputs. We propose that DVC circuits undergo a certain amount of short-term plasticity that allows the brain stem neuronal elements to act in harmony with neural systems that control behavioral and physiological homeostasis.

Animals↗

PubMed1999

The electrically elicited startle blink reflex in patients with schizophrenia: A threshold study of different reflex components.

The electrically elicited blink reflex consists of three components (R1, R2, R3). In humans the excitability of these components is influenced by attentional states. In particular, distraction from the stimulus leads to facilitation of the bilateral R2 and R3. The present study was performed in order to investigate the excitability of the different components of the electrically evoked blink reflex in 13 patients with schizophrenia and 13 normal controls under standard conditions. Therefore, the thresholds of the distinct components were determined without any inhibitory or facilitatory procedure. There was no significant difference in R1 and R2 thresholds between patients and controls. In contrast, the R3 threshold was significantly reduced in schizophrenic patients (R3 threshold = 17.5 mA in normal subjects, 10.5 mA in patients, p = 0. 0001). In recent studies the R3 magnitude was found to be highly susceptible to changes in the attentional state of normal subjects. The lower threshold of R3 in patients with schizophrenia might therefore be a neurophysiological marker of attentional dysfunctions in schizophrenia.

Adult↗

PubMed1980

[Below-zero habituation of the orienting reflex: study in skin resistance reflex (author's transl)].

Two experiments were designed to investigate a below-zero habituation of the skin resistance reflex (SRR) component of the orienting reflex to auditory stimuli. In both experiments, subjects were given additional ten stimulus-presentations immediately after initial habituation (extended habituation, EH procedure), and they were compared with those without EH procedure. Effects of EH procedure upon rehabituation and SRRs to novel stimuli (Experiment I), and upon SRRs to novel stimuli under an additional control condition (Experiment II), were examined. The EH procedure enhanced SRRs to novel stimuli and had no effects on the spontaneous recovery. These results suggested that habituation would not proceed beyond the zero-level by the EH procedure.

Adolescent↗

PubMed1998

[Quantitative analysis of vestibulo-ocular reflex and optokinetic reflex electronystagmography in patients with unilateral loss of vestibular function].

OBJECTIVE: To study changes of the vestibular function in the process of vestibular compensation. METHODS: The electronystagmography recording of spontaneous nystagmus(SN) with tests for vestibulo-ocular reflex (VOR) and optokinetic reflex (OKR) were performed in 105 patients with unilateral loss of vestibular function, the results were analysed quantitatively. RESULTS: (1) Twenty-one patients with courses from 3 days to 6 years presented a SN directed towards the intact side, with an average slow phase velocity (ASPV) of 7.12-12.07 degrees/s. (2) The intensity of VOR nystagmus as a response to the warm-cold water stimulation to the intact ear was lower than that of normal subjects. (3) By 0.167 Hz, 90 degrees sinusional oscillation stimulation, the ASPVs of the patients' VOR nystagmus directed towards the intact and affected sides were lower than that of the normal. A predominance of VOR nystagmus rotation towards the intact side was found in patients with courses < or = 5 years. There was no predominance of VOR nystagmus found in patients with courses > 5 years. (4) There was no significant difference between the optokinetic nystagmus (OKN) intensity of the normal persons and that of patients with lesions outside the cerebellopontine angle and with tumors in cerebellopontine angle which was < 2.5 cm in diameter. The OKN intensity of patients with tumors in cerebellopotine angle with diameters > or = 2.5 cm was lower than that of normal subjects. A predominance of OKN towards the intactside was found in these patients. CONCLUSION: The vestibular function is in inhibitory and the vestibular system becomes rebalanced due to this inhibition in the process of vestibular compensation.

Adolescent↗

PubMed1989

[Cooperation and substitution of the saccadic system and the reflexes of vestibular origin: should the "reflex" concept be revised?].

Neuronal mechanisms of production of ocular saccadic movements are discussed, together with stabilizing movements of vestibular origin, and descriptions given of several neuronal elements constituting the tecto-reticulo-spinal system, the generator of horizontal saccadic movements in the brain stem, the vestibulo-ocular pathway, etc... Analysis of these pathways and of the signals travelling through them suggests that the overall apparatus is not constituted of isolated reflex modules but acts as a true functional unit for cooperation between orientation and stabilization mechanisms. In addition, coordination of synergies between eye and head movements appear to be based on the activity of clearly identifiable neurons. This neuronal implementation of the concept of synergy is completed further by a remarkable functional flexibility. The latter allows substitution by the brain, for example, fo saccades instead of vestibular reflex movements when the latter are deficient because of lesions or disturbances in the coherence of sensory information. The principal conclusion reached is that cognitive factors, which imply representations of body movements in space activated as a function of the subject's goals, must be considered when ocular movement, and gaze control is described.

Animals↗

PubMed1987

[Tonic protective reflexes and reflex response of skeletal muscles].

Models of excitatory tonic protective reflex revealed different reflex responses of skeletal muscles to stimulation of somatic or visceral afferents. The correlation of inhibitory and excitatory responses was found for dogs and rats. The observed phenomena are considered as the development of V. N. Tchernigovsky's idea of interoceptors influences upon skeletal muscles.

Abdominal Muscles↗

PubMed1987

[Comparison of the reflex responses to unexpected stimulation (startle reflexes) in freely moving and chloralose-anesthetized cats].

Comparative study of startle reflexes recorded electromyographically in the same cat was performed under two different experimental conditions: in freely moving animal and after chloralose-anesthesia. A remarkable similarity in the component composition and temporal parameters (latency, duration) of the EMG responses in these two cases was found. The data obtained suggest the functional similarity of startle reflex discharges in freely-moving and anesthetized cats as well as the identity of their corresponding neural mechanisms.

Acoustic Stimulation↗

PubMed1979

[Quantitative measurement of the tendon reflexes. A study on Achilles tendon reflex (author's transl)].

Quantitative analyses of tendon reflexes were performed for the purpose of clinical application. Tendon tap was marked with a WNS-5D semiconductor load cell inserted in the hammer to measure tapping force. Achilles tendon reflex (ATR) was measured with a LAS-0.1 displacement transducer in kneeling position on the chair. In ATR, six factors, i.e. duration of reaction time, the height of the wave, the time from the hammer tap to the top of the wave, the maximum speed of contraction, the time from the hammer tap to the maximum speed and half relaxation time, were analyzed. Correlation between these six factors were discussed. From the analyses of these factors, half relaxation time may serve as the best indicator of clinical status among the factors obtained by analysis of ATR.

Achilles Tendon↗

PubMedDate not supplied

[Diagnostic and prognostic significance of long latency reflexes, somatosensory evoked potentials and the blink reflex in cerebral ischemia].

In order to determine diagnostic and prognostic value of long latency reflexes, blink reflex and somatosensory evoked potentials in patients with ischemic brain disease (IBD), examinations were done in 32 patients of both sexes with IBD, average age 44-76 years. First examinations were performed within first week of the onset of IBD and in majority of patients repeated after 3 and 6 months. Changes of electrophysiological characteristics compared with the degree of IBD, clinical presentation, localization, extent of infarction zone (measured by CT) and functional recovery where analyzed. Electrophysiological changes were predominantly associated with amplitude of physiological response and were in correlation with the degree of IBD, localization and the extent of infarction zone. Latencies were prolonged only in case of subcortical ischemic lesions. Correlation between functional recovery and electrophysiological changes was present only within the structures responsible for certain components of electrophysiological responses and localization of ischemic lesion. In conclusion, electrophysiological examinations are of high diagnostic and predictive value in IBD.

Adult↗

PubMed1980

The bicellular and reflexive membrane junctions of renomedullary interstitial cells: functional implications of reflexive gap junctions.

Renomedullary interstitial cells are loosely organized within the interstitial space surrounding collecting ducts, limbs of Henle, and capillaries of the rat renal medulla. These cells possess long processes, which interact with each other and with cell bodies to form bicellular tight, intermediate, and gap junctions. In addition, both cell bodies and cell processes possess "reflexive" gap and intermediate junctions. Possible functions of renomedullary interstitial cell membrane junctions are discussed. Particular attention is given to a consideration of the functional significance of "reflexive" gap junctions.

Animals↗

PubMedDate not supplied

[Emotional stress during conditioned reflex transformation of heterogeneous instrumental reflexes].

The factors leading to pronounced emotional stress accompanied by changes in electrical activity of hippocampus were studied in four dogs during elaboration of conditioned switching-over of heterogeneous instrumental reflexes. Objectively recorded signs of emotional stress were observed in two cases: when the animal was not accurate enough in discerning defensive and alimentary situations and throughout the improvement of instrumental defensive reflex. Pronouncement of hippocampal theta-rhythm increased at those stages of switching-over elaboration where the probability of successful avoiding pain stimulation was relatively low. The data obtained permit the conclussion that theta-rhythm is the correlate of the degree of the emotional stress and not only a manifestation of general arousal reaction depending on the level of sensory input.

Animals↗

PubMedDate not supplied

[Dynamics of elaboration of conditioned reflex switching over of dissimilar instrumental conditioned reflexes].

Conditioned switching over of heterogeneous instrumental reactions was elaborated in four dogs. The action of a fan served as a switch from alimentary to a defensive situation. In the alimentary situation, the animal, in response to a conditioned stimulus, pressed the pedal with its right foreleg and, in a defensive situation, in response to the same signal, lifted the left paw attached to the lever. In some dogs the switching over was elaborated quite rapidly and easily, while in others it was achieved only on some days of the experiment. In the course of elaboration of the switching over, the animals responded to the trigger signal with bieffector reactions. The basic features of the dynamics of switching over elaboration revealed for classic conditioned reflexes also proved valid for instrumental conditioned reflexes.

Animals↗

PubMed1987

Reflex pathways from group II muscle afferents. 2. Functional characteristics of reflex pathways to alpha-motoneurones.

The convergence of group II muscle afferents on interneurones in reflex pathways has been elucidated by investigating interaction in transmission to motoneurones. Recording was also made from interneurones activated from group II afferents. Maximal group II EPSPs evoked in motoneurones from different muscles (extensors or flexors and extensors) did not summate linearly but with a deficit of 35-40%. The corresponding deficit in summation with Ia EPSPs was 7%. It is suggested that the difference in deficit is caused largely by occlusion due to shared interneuronal discharge zones and that it gives an approximate minimal measure of the convergence of group II afferents from different muscles on the interneurones. Tests with weak group II volleys from different muscles gave no or little evidence for spatial facilitation in the disynaptic excitatory pathway to flexor motoneurones, and there was no or little temporal facilitation of transmission in this pathway. It is suggested that group II excitation of the interneurones in this pathway depends on few afferents giving large unitary EPSPs. Convergence of cutaneous afferents and joint afferents on the interneurones was evidenced by spatial facilitation from these afferents of group II transmission to motoneurones. Convergence on interneurones in the trisynaptic inhibitory pathway from group II afferents to extensor motoneurones was also investigated with the spatial facilitation technique. There was convergence on common interneurones of group II afferents from different muscles (extensors or flexors and extensors) and from cutaneous afferents as well as joint afferents. Trisynaptic group II IPSPs, including those depending on spatial facilitation from different muscles were resistant to recurrent depression from motor axon collaterals and are therefore not mediated by the reciprocal Ia inhibitory pathway. Interneurones with monosynaptic group II EPSPs were recorded from in the dorsal horn and intermediate region. Graded stimulation revealed large unitary EPSPs from few group II afferents. The EPSP evoked by a single group II afferent may produce firing (extracellular recording). Convergence of monosynaptic group II EPSPs from different muscles was rather limited but could be from flexors and extensors. Extensive multisensory convergence onto some of these interneurones was indicated by di- or polysynaptic EPSPs from group II and III muscle afferents, from joint afferents and from cutaneous afferents.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1993

Role of upper esophageal reflex and belch reflex dysfunctions in noncardiac chest pain.

Fifty-four patients examined for noncardiac chest pain (NCCP), showing no esophageal motor disorder or gastroesophageal reflux disease compatible with NCCP, were subjected to an intraesophageal balloon distension test and a study of the belching reflex provoked by intraesophageal air injection. Thirty-three control subjects were also studied, allowing us to define high-threshold belchers (group I) as those who belched during two of three 40-ml distensions and low-threshold belchers (group II) as those who did not. The balloon distension test induced NCCP in 64% of the patients in group I, and in 14% of the patients in group II (P < 0.01). High-threshold belching was a factor favoring the positivity of the balloon distension test. This result supports the hypothesis that esophageal distension by air due to a belching disorder may be the mechanism responsible for NCCP in some patients with an abnormal sensitivity to balloon distension.

Air↗