Conditioned Motor Reflexes Research Articles

PHONETIC REHABILITATION FOR REMOVABLE DENTAL PROSTHETICS

Removable prosthesis is considered as a device with therapeutic, rehab and prophylactic functions, which allows to improve the quality of life of the dentist. Its use is always aimed at solving three problems: restoration of chewing; restoration of pronunciation of sounds; restoration of aesthetic norms of a person.
 Fixation of the complete removable denture depends on the anatomical retention, which is determined by the area and form of the prosthetic bed; from adhesion (capillary forces, viscosity of saliva) and from the functional suction of the prosthesis. For the stabilization of prostheses, the contour of the alveolar appendix and the production of artificial teeth are of special importance.
 Therefore, a complete removable denture is a complex design, which always has a single plan of construction (basis and artificial teeth), but in each case is made taking into account the individual characteristics of the patient's body.
 Adaptation to a complete removable denture is a multi-layered process. Its inalienable component is neuro-reflex mechanisms. From these positions, the habit of prosthetics is explained by the development of cortical inhibition, which leads to the disappearance of the feeling of a foreign subject in the oral cavity. These changes occur on the basis of the general law, according to which repeatedly the stimulus becomes a brake agent. Based on masticatography, it has been established that addiction to prosthetics is associated with the appearance, perfection and consolidation of new conditioned motor reflexes. An important component of the adaptation process in patients with prosthetics is psychological adaptation. It is believed that it represents the sum of complex conditioned-reflex responses of the patient, which belong to the sphere of human emotions and determine the degree of satisfaction with dentures. The significance of psychological factors in the development of adaptation to prosthetics stimulates the creation of new and improved existing methods for assessing the psycho-emotional state of orthopedic dental patients. According to the results of these methods, high personal anxiety is the main factor that causes the development of psycho-emotional stress during orthopedic treatment.
 There is also a speech adaptation, which is the result of the interaction of the active organs of the articulation apparatus with dentures. The appearance of improper pronunciation of sounds is considered as a result of motor and sensory disorders of the central or peripheral nature: changes in the structure of the articulation apparatus and violations of muscle inertia involved in articulation; reduction of peripheral hearing and violations of the auditory perception of the central character. Wrong pronunciation is most often observed in groups of whistling, silent sounds, [p], [l], which are characterized by complexity of sounding and, accordingly, the complexity of articulation work. A certain range of works is devoted to methods of studying pronunciation of sounds from different points of view: physical (acoustic), anatomical-physiological and linguistic.
 Detection of defects of articulation was done by listening. In a number of studies the study of violations of articulation of sounds was carried out using anatomical-physiological and acoustic characteristics with the help of apparatus. Modern methods of speech research are based on listening, audiometry and spectral analysis of sound.
 Consequently, the features of rehabilitation of toothless patients with the help of a complete removable denture are widely covered in the literature. The concept of pathogenesis of violations with full or partial adentia and about mechanisms of their overcoming with the help of dentures is deepened. However, until now, the literature remains almost uninvolved into the consideration of phonetic aspects as in the analysis of anatomical and physiological features of the toothless mouth during preparation for prosthetics, and at different stages of the use of dentures.

Hippocampal state-dependent behavioral reflex to an identical sensory input in rats.

We examined the local field potential of the hippocampus to monitor brain states during a conditional discrimination task, in order to elucidate the relationship between ongoing brain states and a conditioned motor reflex. Five 10-week-old Wistar/ST male rats underwent a serial feature positive conditional discrimination task in eyeblink conditioning using a preceding light stimulus as a conditional cue for reinforced trials. In this task, a 2-s light stimulus signaled that the following 350-ms tone (conditioned stimulus) was reinforced with a co-terminating 100-ms periorbital electrical shock. The interval between the end of conditional cue and the onset of the conditioned stimulus was 4±1 s. The conditioned stimulus was not reinforced when the light was not presented. Animals successfully utilized the light stimulus as a conditional cue to drive differential responses to the identical conditioned stimulus. We found that presentation of the conditional cue elicited hippocampal theta oscillations, which persisted during the interval of conditional cue and the conditioned stimulus. Moreover, expression of the conditioned response to the tone (conditioned stimulus) was correlated with the appearance of theta oscillations immediately before the conditioned stimulus. These data support hippocampal involvement in the network underlying a conditional discrimination task in eyeblink conditioning. They also suggest that the preceding hippocampal activity can determine information processing of the tone stimulus in the cerebellum and its associated circuits.

The effects of microinjection of neurotensin into the caudate nucleus of the rat brain on the performance and extinction of a conditioned motor reflex.

The studies reported here demonstrate that microinjection of neurotensin into the caudate nucleus of the rat brain facilitated extinction of a conditioned motor reflex with reinforcement provided by drinking. Neurotensin had positive effects on the process of post-extinction inhibition in subsequent experiments. Neurotensin microinjections had no marked effect on the performance of the conditioned reflex, though it weakened the emotional tension of the animals in an "open field" test. It is concluded that the functional importance of neurotensin at the level of the caudate nucleus is associated less with the regulation of motor function than with optimizing the motivational-emotional state of the animal.

Interactions between homogeneous conditioned motor reflexes during conditioned reflex switching: transfer of learning and interference.

Studies in rabbits of the time course of the formation of conditioned reflex switching of homogeneous reflexes showed that learning involved three main stages, characterized by the extent of stability of the conditioned reflexes, their interaction, and the level of switching. Formation of conditioned reflex switching was found to involve transfer of motor learning and interference of motor reflexes.

Inhibitory correction of conditioned reflex behavior in rats at different stages in its realization.

1. Inhibitory correction of the motor program of a conditioned-reflex food-procuring behavior is more effective the nearer the application of the differential signal is to the moment of entry into the activity. 2. The longer the sequence of actions realized up to the moment when the inhibitory corrective signal is presented, the more inertia will be manifest by the components of the conditioned motor reflex. 3. The activating effects of the proprioceptive and situational stimuli immediately preceeding the reinforcement are concurrent with the inhibitory effects of the differential stimulus.

Conditioned motor reactions in free-moving elasmobranchs and bony fishes.

Food-getting conditioned motor reflexes to light and darkness discrimination were developed in elasmobranchs (the sharks Scyllium canicula and Galleus canis) and bony fishes (Mugil capitocum). Several distinctions in ecological and conditioned motor behavior were observed in sharks with low and high degrees of organization. There were significant differences between elasmobranchs and bony fishes in ecological and food-getting behavior and in conditioned reflex reactions. The nervous activity of elasmobranchs is characterized by a lower and more primitive degree of organization, compared to bony fishes.

Physiological analysis of the effect of micropolarization on trace processes.

1. The combination of rhythmic lifting of one forelimb and simultaneous continuous pressor stimulation of the same limb in cats leads to the formation of a conditioned motor reflex to time. Trace motor responses in the assigned rhythm can be detected either during continuous pressor stimulation or during micropolarization of the sensomotor or motor cortex, the body of the caudate nucleus, corpus callosum, and mesencephalic reticular formation by currents of 0.3–1.5 μA. 2. A combination of rhythmic lifting of the forelimb with continuous micropolarization of the sensomotor cortex in the region of representation of the lifted limb by a current of 0.5–1.5 μA also leads to formation of a conditioned reflex to time. Trace motor responses are detected to continuous micropolarization of this same cortical area alone or to subthreshold pressor stimulation of the trained limb alone. 3. It is suggested that these phenomena may have a common physiological mechanism: prolonged activation (through pressor stimulation or micropolarization) of sensory and motor cortical projections of the proprioceptive stimulus facilitates the formation of a trace reflex, such as a conditioned reflex to time.

Mechanisms of participation of caudate nuclei in the organization of conditioned motor reflexes

Mechanisms of participation of caudate nuclei in the organization of conditioned motor reflexes

Conditioned motor reflexes in cats with damage to the hippocampus

Hippocampal damage in cats led to: a) A temporary suppression of previously elaborated motor feeding conditioned reflexes (CR); b) A retardation (nearly twice) in the rate of elaboration of a new CR; c) A marked prolongation of latency of CR; d) A disinhibition of negative CR. li]2.|In experiments in which the animals were trained to approach the left-side feeder and press a pedal at one signal and the right-side feeder at another signal, destruction of the hippocampus led to frequent errors in the choice of the proper side of reinforcement.

Conditioned motor reflexes in cats with damage to the globus pallidus.

1. Unilateral destruction of globus pallidus does not influence natural conditioned reflexes. Bilateral destruction results in temporary disappearance of natural as well as artificial conditioned motor reflexes. Further training is necessary for the reestablishment of these reflexes. However, the training period is twice that required in the preoperative period. Reestablished conditioned reflexes manifest themselves with long latency. Movements are performed with accuracy but very slowly. 2. After partial bilateral destruction of the pallidum, animals that have been trained not only to press a pedal, but also to make a choice between a right or a left feeding tray, lose the latter ability. After the reestablishment of conditioned reflexes, the animals make a correct choice of side only 50–70% of the time. 3. After total bilateral destruction of globus pallidus, the animals lose artificial conditioned reflexes; these are not reestablished even after four months of training, though natural conditioned reflexes can be reestablished but with great difficulty.

Behavioural and electrophysiological changes during avoidance conditioning to light flashes in the rat

In freely moving rats with chronically implanted epidural electrodes behaviour, respiration, motion, ECoG, visual evoked potentials (EP) and after-discharges (AD) were recorded during avoidance conditioning to flash series, after preceding short-lasting habituation to the experimental situation and to the CS. The changes in behaviour and in the electrophysiological parameters recorded during our experiments may be arranged in three regularly occurring phases: (a) phase of disturbance, (b) phase of adaptation and (c) phase of well adapted behaviour. The phase of disturbance occurs in the awake, freely moving animal with every essential change in situation. It is characterized by general excitation, acceleration of respiration, large decrease in amplitude of EP, strong desynchronization of ECoG and non-appearance of AD after light flashes. Intensity and duration of these changes are correlated with the intensity of disturbance and the degree of training. This phase is very quickly replaced by the phase of adaptation in which excitation becomes more and more confined, and goal-directed behaviour develops. Now the occurrence of inhibitory phenomena ( e.g. arrest reaction) can be observed. EP reach a maximum, background activity of the ECoG is still desynchronized but has a tendency to decrease in frequency and rise in amplitude, and AD appear. The phase of adaptation gradually changes into the phase of well adapted behaviour, in which the animal displays an unstrained, quiet behaviour. The conditioned motor acts are performed nearly automatically. EP, ECoG and AD are the same as in a quiet undisturbed animal which has a tendency to fall asleep. From all this one can see that the same general laws are fundamental to habituation, conditioning, and extinction, getting their specific characters through special processes corresponding to the specificity of the situation, for instance the special motor activation during the conditioned motor reflex (occurrence of 6–9 c/sec rhythm) or the extremely strong occurrence of inhibitory phenomena during extinction (EP and number and duration of AD are particularly increased).

Investigation of the trace changes in the electroencephalogram in man during the formation of motor conditioned reflexes

A study was made of the EEG changes in healthy adults during elaboration of conditioned reactions. At the beginning of the conditioned motor reflexes elaboration there sets in a depression of the main rhythm in the EEG of the sensory motor area, following the conditioned motor reaction with its subsequent restoration. Later a rise of the amplitude of the main rhythm or the appearance of acute impulses is noted in this area. Trace reactions in the form of “reciprocal” changes of electric activity were observed in the sensory motor and occipital areas. During the restoration of the main rhythm in the anterior portions a reduction of the α-rhythm was seen in the occipital areas, and vise-versa. These changes occurred after stabilization of the conditioned motor reaction.

General and local changes in the electroencecphalogram during the formation of conditioned motor reflexes in man

The author studied the EEG changes in man during the formation of conditioned motor reflexes to complex sound stimuli.

The encephalogram and electromyogram of motor conditioned reflexes after paralysis with curare

The author, like Liwanow, distinguishes three stages of bioelectric changes in the brain of a rabbit during the formation of a defensive motor conditioned reflex. He also separates a fourth stage, an already formed conditioned reflex, in which the rhythmic activity in the kinaesthetic analyzer disappears. A number of rabbits were subjected to the following procedures: 1. (a) Paralysis of the extremity with curare. 2. (b) Substitution of active with passive movements during the operation of the conditioned stimulus. 3. (c) The formation of conditioned motor reflexes after administration of pontocaine into the joint. In the light of these studies, the author discusses the factors underlying the appearance and disappearance of the driven rhythmic activity in the kinaesthetic analyzer (stages III and IV) and emphasizes the importance of proprioceptive stimuli for the formation of motor conditioned reflexes.

Method of graphic recording of conditioned motor reflexes

Method of graphic recording of conditioned motor reflexes

Studies on the electrical activity in the auditory and motor analyzers of the human brain cortex, during the formation of a defensive conditioned motor reflex

Studies on the electrical activity in the auditory and motor analyzers of the human brain cortex, during the formation of a defensive conditioned motor reflex

Electrical method for the simultaneous study of conditioned secretory and motor reflexes

Electrical method for the simultaneous study of conditioned secretory and motor reflexes

The Influence of Degrees of Freedom Upon Stereotyped Conditioned Motor Reflexes in the Sheep

The Influence of Degrees of Freedom Upon Stereotyped Conditioned Motor Reflexes in the Sheep

Avoidance of Nervous Strain in Experimental Extinction of the Conditioned Motor Reflex

Avoidance of Nervous Strain in Experimental Extinction of the Conditioned Motor Reflex

Effects of Insulin Shock on Behavior and Conditioned Reflex Action in the Well Trained Sheep.

Insulin shock has radically, and perhaps permanently, altered the behavior of a sheep whose conditioned reflexes and general behavior have been studied for 7 years. During the year preceding the insulin experiment the conditioned motor reflex had gradually failed (Fig. 1-A) although the sheep remained quiet and alert during the 20-minute test period. The sheep was started on 10 units of insulin and the daily dose was increased by 10 to 15 units until coma and convulsions occurred. First signs of coma were observed at 160 units but dosage was carried to 280 units in an effort to secure typical shock phenomena. Convulsions were induced on 7 successive days. No discrepancies in the results as given below for a typical day were observed. Insulin is given to the fasting sheep at 9 A. M.; in 5 hours it is standing with head drooping, lips twitching, and must be carried into the testing laboratory. It is placed upon the observation platform with great difficulty. When in the testing frame the sheep is induced to stand but soon slowly sinks. After a few minutes it rises and stands for a few minutes, then sinks again. When standing, the head gradually droops, the eyelids close; then suddenly the head is raised and the eyes are opened. This sequence is repeated many times throughout the first part of the observation period. At this time the heart rate is normal or below normal (80-60); breathing is labored and noisy. The animal is now tested. It not only shows no conditioned motor (defensive) reflex but fails to respond to any outside stimulus. In an effort to show what is happening to the animal at all times, the conditioning test (sound of buzzer for 10 seconds followed by shock to the left foreleg) is repeated at the usual 5-minute intervals in the coma, the recovery period, and for some time after. After about an hour of fairly severe convulsions glucose is administered by mouth.