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Attack, avoidance, and escape reactions to aversive shock.

Aversive stimuli are known to produce the behaviors of both escape and attack. The interaction between these two basic reactions was studied with rats and monkeys using many shock-escape and shock-avoidance procedures. All procedures produced attack if a target was present, the attacks occurring shortly after shock delivery. The number of attacks during escape or avoidance was a direct function of the number and duration of shocks received. Consequently, any aspect of the procedure that produced many shocks also produced many attacks such as initial acquisition, extinction, or an increase of the response requirement for escape. The escape tendency acquired prepotency over the tendency to attack since successful escape eliminated attack behavior. The attack tendency retarded escape behavior only during acquisition when the preoccupation with attack precluded the opportunity to learn the escape response. This mutual interference of escape and attack was eliminated when the attack and avoidance tendencies were combined by using biting attack as the shock-avoidance response. The result was unusually rapid conditioning of the biting-attack response. These interactions indicate that both the attack and escape tendency should be considered whenever aversive stimulation is delivered.

Aggression↗

Tonic inhibition alternates in paired neurons that set direction of fish escape reaction.

Crossed antagonism between activities in neurons subserving alternating movements such as swimming or walking has been described in a number of systems. The role of reciprocal inhibition has been implicated in these activities, but involvement of rhythmic ongoing fluctuations of membrane potential, called synaptic "noise," has not been examined. In the Mauthner (M) cells, which control the direction of escape, this activity is inhibitory. We report that in the zebrafish (Danio rerio), inhibitory synaptic noise exhibits prolonged bursts of rhythmic, inhibitory postsynaptic potentials, which attenuate the M cell's sensibility to excitatory sensory drives. Furthermore, paired intracellular recordings have shown that inhibitory synaptic noise alternates between two distinct states, noisy and quiet, which are out of phase in the two cells. Firing of either M cell resets this pattern by reducing the inhibition in the contralateral one. This suggests that an avoidance reflex in one direction may favor initiation, by the opposite M cell, of a subsequent escape toward a more appropriate location.

Action Potentials↗

[The role of emotiogenically positive areas of the hypothalamus in realizing instrumental food and escape reactions].

In experiments with dogs was shown that the activating electrostimulation (200 cps; 0.5 ms; 15-20 V) of the emotional positive structures of the hypothalamus (having been able to evoke self-stimulation) reproduced neither defensive nor alimentary adaptive motor reaction. Moreover, such a stimulation inhibited both alimentary (unconditioned and instrumental) and defensive instrumental conditioned responses.

Acoustic Stimulation↗

[The neuronal mechanisms of the escape reaction to stimulation of the statocyst receptors in the freshwater snail].

Tilts of the freshwater snail Planorbarius corneus, resulting in statocyst receptor stimulation, induced the defensive reaction including pulling down of the shell, shortening of the foot, inhibition of locomotion and feeding. The preparation of the central nervous system has demonstrated that many inter- and motoneurons from different ganglia were involved in this reaction. Usually the reaction was of "all or none" manner. The repeated reaction of the second tilt could be evoked not earlier than 10-20 s after the previous one. It is concluded that the defensive reaction to statocyst receptor stimulation is a "fixed act" determined by a special central mechanism (a central program). The reactions to stimulation of statocyst receptors and skin nerve are proved to be generated by the same mechanism.

Animals↗

[The formation of instrumental escape reactions based on movements induced by stimulation of the motor cortex in dogs].

The purpose of the study was to find out the possibility of instrumentalization of movements induced by stimulation of the motor cortex (MI) in dogs. The scheme of conditioning was as follows. The electrical shock applied to the right forepaw was used for a weak painful stimulation. In 3 s, the stimulation of the MI was added, which elicited the right hind limb flexion. The shock was switched off at the moment of the hind limb lifting. After several trials, the shock began to elicit the hind limb flexion before the cortical stimulation. The scheme of conditioning excluded the possibility of instrumentalization of irrelevant chance movements. Prolonging the shock by 2 s after the cortical stimulation led to extinction of acquired responses. Renewal of reinforcement of the hind limb movements by immediate switching off the shock led to recovery of conditioned reactions. Thus, the instrumental nature of the responses has been proved. The obtained results are of particular interest in connection with the findings that similar acquisition of instrumental reaction on the basis of food reinforcement is impossible. The results support the assumption that the "instrumental" conditioned connection can be addressed directly to the motor cortex.

Animals↗

[Neuropeptides in the mechanisms of the activation of escape reactions induced by stimulation of the ventromedial hypothalamus during food motivation satiation].

Influence of food intake on hypothalamically induced avoidance reactions have been studied in rabbits. It was shown that first contact with food and beginning of food intake accompany with activation of avoidance reactions. Central action of cholecystokinin-octapeptide, pentagastrin, beta-endorphin and naloxone on avoidance reactions of fed and fasted rabbits before and during food intake was investigated. It was found that injection of cholecystokinin and naloxone, which had a satiated effect, act on avoidance reactions similarly in fed and fasted rabbits. Beta-endorphin inhibits avoidance behavior, and only pentagastrin activates avoidance reactions of fasted but not fed rabbits. It is concerned that influence of feeding motivation may modulate avoidance behavior by participation of endogenous gastrin-like peptide release into the perineuronal area during contact of rabbits with food and beginning of its intake.

Animals↗

[Effect of stimulation of structures causing an escape reaction on the self stimulation reaction in rats].

The effect of emotionally negative actions with various intensities, on the activity of the positively reinforcing brain system was studied in chronic experiments on rats. In each rat "purely" negative and positive sites were determined by well-known methods of pedal self-stimulation, of reactions of active and passive avoidance. It was shown that elimination of both central and peripheral negative actions enhances the activity of the positive reinforcement system; complex neurophysiological relations exist between systems of positive and negative reinforcement which cannot be defined solely as a reciprocal interaction.

Animals↗

[The escape reactions in cats during electrical stimulation of the hypothalamus leading to the occurrence of aggressive behavior].

The influence of brain electrical stimulation, which induced some elements of agonistic behavior, on the preference of an animal of one of two compartments of the experimental chamber was studied in 7 male cats with implanted hypothalamic electrodes. The animals avoided the compartment in which they were stimulated. Self-stimulation reaction could not be formed on the basis of the electrical brain stimulation inducing certain elements of agonistic behavior. Passage latencies were shorter when an animal left the less preferential compartment that in the case when in started from the more preferential one. The obtained evidence suggests that hypothalamic stimulation producing certain elements of agonistic behavior evokes in an animal a negative internal state.

Aggression↗

[A comparative analysis of the effect of nootropic preparations with different chemical structures on the failure of the escape reaction in rats].

The nootropic agents pyroglutamyl-D-alanine amide (TGS-20), mechlofenoxate, and mexidole versus piracetam were tested for their effects on the reversible impairments of cognitive brain functions, on the demolition of active avoidance responses in rats. TGS-20 (1 mg/kg/day) and mexidole (10 mg/kg/day) injected intraperitoneally 30 minutes prior to the experiment showed a normalizing effect in smaller doses than did piracetam (300 mg/kg/day). Mechlofenoxate (50 mg/kg/day) displayed a lower protective effect.

Animals↗

[Effects of heptapeptide of the tuftsin group with nootropic components of action and piracetam on formation of escape reaction in normal conditions and in conflict situation].

In this work we have compared the effect of Tuftsin Group synthetic heptapeptide (TP-1) and Piracetam on learning of avoidance response and its restoring after disturbance provoked by unexpected changes of previously established cause-effect relations in experimental environment. We have pointed out that both of the drugs improve learning but the dynamics is different, namely: Piracetam causes the greatest improvement on the 1st day, meanwhile the Heptapeptide--on the 4th day. Both of them preclude from disturbing avoidance response and this protective action of peptide is more effective.

Animals↗

[Study of lever-holding phenomenon during the escape reaction in rats].

A "preparatory" hypothesis according to which the bar-holding develops as a preparatory response placing an animal in an advantageous position for the reaction on the subsequent action of the electric current has been experimentally examined. Comparing the avoidance training under the condition allowing the bar-holding until the next conditioned and unconditioned stimuli, and under conditions excepting such long holding it has been established that in first case the number of bar-holding responses is more and the avoidance responses are less than in the second one. It contradicts the "preparatory" hypothesis. It has been shown that the dynamics of inter-trail and the bar-holding responses results from stimulus generalization and discrimination.

Animals↗

[The effect of the new nootropic dipeptide GVS-111 in different functional disorders of the escape reaction].

The authors studied the effect of a new nootropic agent with anxiolytic properties GVS-111 (ethyl ether N-phenylacetyl-L-prolylglycine) on formation of the avoidance reaction (AR) in rats and its functional disorders which were induced by two methods. In one case the stereotype of the relations between the stimulus, reaction and its consequence which developed during the experiment were urgently disturbed: the change of the animal to the other half of the chamber in response to a conditioned stimulus did not lead to its cutting off and prevention of the electropain stimulation for three successive combinations (AR error). In another case the spatial stereotype of the experiment was altered by changing the place of the opening through which the animal avoided the stimulus (spatial remodeling). Intraperitoneal injection of GVS-111 (0.1 mg/kg/day) improved the learning, but the effect differed from experiment to experiment. Along with this, the dipeptide prevented AR disturbance during the error and quickened restoration of the habit in spatial remodeling. It was shown earlier that AR disorders during an error are prevented by anxiolytics and nootropic agents but during spatial remodeling only by nootropic agents. It may be assumed that the positive effect of GSV-111 on AR in functional disorders is due to its nootropic effect.

Acoustic Stimulation↗

Behavioral analysis of diffuse noxious inhibitory controls (DNIC): antinociception and escape reactions.

'Diffuse noxious inhibitory controls' or DNIC is the inhibition of multireceptive neurons in the dorsal horn of the spinal cord that results when a noxious stimulus is applied to a region of the body remote from the neuron's excitatory receptive field. Although this phenomenon is well-documented, the behavioral consequences of DNIC are not clear. The present study was undertaken to determine how nocifensor withdrawal reflexes evoked by a noxious stimulus are altered by application of a second noxious stimulus to a distant part of the body. The tail flick or hindpaw withdrawal reflex of lightly anesthetized (0.6-1.0% halothane) rats was measured before, during and after another appendage was placed in water ranging in temperature from 45 to 54 degrees C. When the forepaw or hindpaw was placed in water exceeding 49 degrees C the tail flick reflex to acute noxious radiant heat was inhibited. In contrast, noxious conditioning stimuli, regardless of temperature or location, had no effect on the latency for hindpaw withdrawal evoked by an acute noxious stimulus, but did produce a change in reflex topography from flexion to extension. These results, along with previous research on DNIC, suggest that intense noxious stimuli: (1) inhibit the tail flick reflex via inhibition of multireceptive neurons in the dorsal horn; (2) disinhibit hindpaw extensor motoneurons by inhibiting the activity of multireceptive neurons involved in hindlimb flexion; and (3) reduce pain sensation by inhibiting multireceptive neurons projecting to the brain (see Model in Discussion).

Animals↗

Escape behaviour in the stomatopod crustacean Squilla mantis, and the evolution of the caridoid escape reaction.

The mantis shrimp Squilla mantis shows a graded series of avoidance/escape responses to visual and mechanical (vibration and touch) rostral stimuli. A low-threshold response is mediated by the simultaneous protraction of the thoracic walking legs and abdominal swimmerets and telson, producing a backwards 'lurch' or jump that can displace the animal by up to one-third of its body length, but leaves it facing in the same direction. A stronger response starts with similar limb protraction, but is followed by partial abdominal flexion. The maximal response also consists of limb protraction followed by abdominal flexion, but in this case the abdominal flexion is sufficiently vigorous to pull the animal into a tight vertical loop, which leaves it inverted and facing away from the stimulus. The animal then swims forward (away from the stimulus) and rights itself by executing a half-roll. A bilaterally paired, large-diameter, rapidly conducting axon in the dorsal region of the ventral nerve excites swimmeret protractor motoneurons in several ganglia and is likely to be the driver neuron for the limb-protraction response. The same neuron also excites unidentified abdominal trunk motoneurons, but less reliably. The escape response is a key feature of the malacostracan caridoid facies, and we provide the first detailed description of this response in a group that diverged early in malacostracan evolution. We show that the components of the escape response contrast strongly with those of the full caridoid reaction, and we provide physiological and behavioural evidence for the biological plausibility of a limb-before-tail thesis for the evolution of the escape response.

Animals↗