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PubMed1996

Escape behavior - brainstem and spinal cord circuitry and function.

Recent work has demonstrated that the neural circuits mediating escape reactions in lower vertebrates and mammals have a common framework, with only two excitatory central synapses in the reflex arc. This relatively direct linkage from sense organs to muscles and the fact that segments of the network also transmit other motor commands help guarantee that escape always has priority over ongoing behaviors. Yet, modulation and plasticity contribute some variability to the expression of escape and, therefore, to the adequacy of its survival function.

Animals↗
PubMedDate not supplied

[The neurotransmitter basis of mollusk behavior: the control of the choice between exploratory and defensive responses to the presentation of an unknown object].

The role of serotonin and opioid peptides in decision making was studied in the pond snail Lymnaea stagnalis. It was shown that 5-HTP increased the number of searching responses to a sudden presentation of a novel object. Opiate antagonist naloxone decreased the number of searching responses and increased the number of defensive and escape reactions. The effect of 5-HTP and naloxone on decision making appear to be coordinated with their effects on their behavioural state.

5-Hydroxytryptophan↗
PubMed1979

Peripheral stimulation in mice induces short-duration analgesia preventable by naloxone.

Peripheral stimulation was applied to mice by mild caudal electrostimulation, by mechanical pressure or by footshock for 30 sec, before testing on a 52 degrees C hot plate. Reaction times to paw lick and to escape from the hot plate were recorded. Analgesia could be elicited and measured by these procedures. It was of short duration, declining in a minute, and was antagonized by low doses of naloxone. The analgesia measured by the escape reaction time could be elicited after multiple caudal electrostimulation as well as in morphine-tolerant mice, and it could still be reversed by naloxone. An opioid link is thus involved in this phenomenon, which also supports the notion of more than one opioid pathway existing in the brain. The short period of analgesic cover afforded in the face of noxious stimuli would permit aversive action to be taken in nature and thus might represent the prime functional role of enkephalins in the brain.

Analgesia↗
PubMed1978

Evaluation of functional degeneration of the amazon-ant Polyergus rufescens Latr. under an influence of socially parasitic way of life.

In certain, infrequently occurring, favorable circumstances the ants P. rufescens can display patterns of behavior which seem to be disappearing as a result of their parasitic way of life: the ability to food themselves, independently though ineffectively, elements of the offspring-protection behavior, transporting of nestmates, escape reaction. Similar events reinforce the infrequently used, latent reflexes, preventing their complete extinction. It is supposed that the characteristic in conventional parasitism disappearance of certain elements of behavior is inhibited by a social way of life. It may also be true of other, non-insect communities.

Animals↗
PubMed1992

[Changes in EEG and higher nervous activity of rats during cerebral anti-ischemic protection by acelysin].

The water-soluble aspirin (acelysin) has been used as an anti-ischaemic protector when injected in the dose of 150 mg/kg 30 min before ischaemia. The EEG has been registered during the whole period of experiment and the total EEG power index has been calculated. The higher nervous activity has been evaluated during analysis of rat's abilities for elaboration of conditional reflex of an active escape reaction in Y-labyrinth. The results have demonstrated the complete rehabilitation and restoration of brain functional activity 8 days after endurance of brain ischaemia under protection of acelisin.

Animals↗
PubMed1991

Role of medullary networks and postsynaptic membrane properties in regulating Mauthner cell responsiveness to sensory excitation.

A benefit of studying well-defined networks at a cellular level is that it might be possible both to place these details in the context of the specific function of the network and to extract general principles applicable to more complex systems. The Mauthner cell system in teleosts is one such vertebrate network where a single impulse can trigger a vital escape reaction, the C start, in response to auditory or visual stimuli. We review here experiments concerned with the organization, at the cellular level, of the afferent circuits impinging on the Mauthner cell and with certain intrinsic membrane properties of the Mauthner cell that contribute to shaping the threshold and expression of the C start. One concept that emerges is related to the interaction between excitatory and inhibitory drives to the Mauthner cell. It seems that every major afferent drive to this neuron also excites a feedforward inhibitory network which, in turn, exerts a major role in establishing and regulating the threshold of the escape response. This design feature is complemented by the Mauthner cell's membrane properties which contribute to the behavioral threshold but exhibit nonlinearities, as excitation begins to overcome inhibition. Finally, we have compared in detail the frequency-dependent characteristics of inhibition and excitation, as revealed by studies of individual identified synaptic connections. This comparison emphasizes the notion that although inhibition is maximized for weak transient stimuli, it becomes depressed at auditory stimulus frequencies that facilitate excitatory transmission and evoke the escape response.

Acoustic Stimulation↗
PubMed2006

Interaction of two swimming Paramecia.

The interaction between two swimming Paramecium caudatum was investigated experimentally. Cell motion was restricted between flat plates, and avoiding and escape reactions were observed, as well as hydrodynamic interactions. The results showed that changes in direction between two swimming cells were induced mainly by hydrodynamic forces and that the biological reaction was a minor factor. Numerical simulations were also performed using a boundary element method. P. caudatum was modelled as a rigid spheroid with surface tangential velocity measured by a particle image velocimetry (PIV) technique. Hydrodynamic interactions observed in the experiment agreed well with the numerical simulations, so we can conclude that the present cell model is appropriate for describing the motion of P. caudatum.

Animals↗
PubMed1980

Passive avoidence learning in the young rat.

A step-through locomotor passive avoidance task is described requiring the suppression of a spontaneous escape reaction from a cool toward a warm compartment in order to avoid an electric shock delivered in the warm side. We observed no lerning of this task at 9 days of age, a very low but significant level of acquisition at 11 days, a slow but progressive improvement of avoidance from the 13th until the 17th day when the adult capacity was achieved, and a marked increase in the rate between 17-20 days.

Aging↗
PubMed1977

Effect of toloxatone on behaviour of primates.

1. The effects of (3-methyl)-3-phenyl-5-hydroxy-methyl-2-oxazolidinone (toloxatone) were studied on the behaviour of three species of primates: baboon, rhesus monkeys and chimpanzee. 2. The activity against reserpine-induced depression is observed in baboon as in rodents. 2. The administration of toloxatone induces three effects which probably have the same origin: suppression of feeding inhibition of the subordinate baboon, improvement of escape reaction in the conditioned chimpanzee, increase in general activity and the active component of social behaviour in grouped rhesus monkeys. These three effects can be interpreted as resulting from the stimulating effect of toloxatone, or more precisely from a disinhibiting effect. 4. Contrary to amphetamine, toloxatone does not induce, even at high or repeated doses, behavioural disturbances.

Administration, Oral↗
PubMed2000

Effects of opioid receptor blockade on defensive behavior elicited by electrical stimulation of the aversive substrates of the inferior colliculus in Rattus norvegicus (Rodentia, Muridae).

RATIONALE: Electrical or chemical stimulation of some structures of the midbrain tectum, such as the dorsal periaqueductal gray matter, deep layers of the superior colliculus and inferior colliculus induce fear and flight behavior. These structures constitute the main neural substrates commanding defensive behavior in brainstem. Many neurotransmitters are implicated in the modulation of aversion at the mesencephalic level. OBJECTIVE: The aim of this work is to investigate the involvement of opioid mechanisms in modulation of defensive behavior in dorsal mesencephalon. METHODS: Male Wistar rats were fixed in a stereotaxic frame and a chemitrode was implanted into the midbrain, targeted to the central nucleus of the inferior colliculus. In the present study, the effects of peripheral and central administration of naloxone, naltrexone or naloxonazine on aversive thresholds (freezing and escape reactions) elicited by electrical stimulation of the midbrain tectum were determined. RESULTS: Peripherally and centrally administered naloxone caused a significant increase in the freezing and flight thresholds elicited by electrical stimulation of the aversive substrates of the inferior colliculus. These effects were confirmed by peripheral and central administration of naltrexone and by microinjections of naloxonazine in inferior colliculus. CONCLUSIONS: These findings suggest that endogenous opioids are involved in the modulation of the aversive behavior elicited by midbrain tectum stimulation. Since microinjections of naloxonazine in the central nucleus of the inferior colliculus caused a significant increase in the aversive thresholds elicited by electrical stimulation of this structure, it is possible that micro1 opioid receptor located in this nucleus may be critically implicated in this neural circuitry.

Animals↗
PubMed1990

Aversion induced by electrical stimulation of the mesencephalic locomotor region in the intact and freely moving rat.

Electrical stimulation of the so-called "mesencephalic locomotor region" (MLR) in the acute mesencephalic and restrained rat is known to induce locomotion. In the intact and freely moving rat, electrical stimulation of an area coextensive with MLR is reported to elicit an apparently aversive type of behavioral response. Indeed, the description of this behavioral response is very similar to the description of the prototypical escape reaction elicited by electrical stimulation of the periaqueductal gray (PAG), a structure of the so-called "brain aversive system." In this study, we investigated if, as is the case for PAG stimulations, these MLR electrical stimulations are also aversive in nature. To that end, MLR-stimulated rats were subjected to the switch-off test, in which the stimulated rat learns to interrupt the stimulation by pressing a bar. It was found that electrical stimulation of MLR sites, positive for apparently aversive behavior, supports the learning of the switch-off behavior, which demonstrates the aversive nature of such stimulations. Furthermore, the switch-off latency (time elapsed between the onset of the stimulation and its offset by a press of the bar) was shown to decrease when the intensity of the electrical stimulation is increased or when the interpulse interval is decreased, which suggests that the generated aversive state is graded by the strength of the stimulation. It is, hence, proposed to extend the "brain aversive system" to the MLR.

Animals↗
PubMed1974

Some factors involved in the comparison of response systems: acquisition, extinction, and transfer of head-poke and lever-press Sidman avoidance.

Head poking, a suggested natural escape reaction to shock for the rat, was compared to lever pressing in a Sidman avoidance study. Both responses could be emitted at any time, but only one was effective in a given session. Acquisition and extinction of the two responses were compared under both signalled and unsignalled avoidance. Then, a test for transfer was conducted in which acquisition conditions were re-instated, but the effectiveness of the responses was reversed. Three differences between responses were noted: (a) head poking was superior in reducing shock rates under signalled conditions; (b) head poking was more resistant to extinction, especially under signalled conditions; (c) under unsignalled conditions, animals were unable to learn to head poke if they had previously learned to lever press. Findings a and c were pursued in later experiments. Finding a depended on the location of the warning signal with respect to the response system. When the lever press required approach to the warning signal, the head poke was superior. But when the head poke required approach to the warning signal, the two responses were equally effective. Finding c depended on the absence of feedback for head poke during transfer. Two conclusions are offered: first, the two responses appear to obey the same laws when their topographical differences are taken into account. Second, response feedback appears to be more critical in transfer than in original acquisition.

Acoustic Stimulation↗
PubMed1993

Ultrastructure of the circuit providing input to the crayfish lateral giant neurons.

Labeled or otherwise identified neurons of the crayfish lateral giant escape reaction circuit were examined electron microscopically and the findings compared to expectations from physiology. Terminals of primary afferents contained clear, approximately 45 nm, irregularly round synaptic vesicles, while sensory interneuron terminals had slightly larger, 50 nm, more strictly round vesicles, permitting tentative classification based on anatomical criteria. Excitatory synapses on the lateral giants, believed from physiology to be electrical, generally had some gap junctions, but these were almost invariably paralleled by more prominent chemical junctional regions of unknown function. There may also be a class of interneurons making purely chemical synapses on the lateral giants. Synapses from primary afferents to sensory interneurons, believed from physiology to be cholinergic, had purely chemical morphology. Synapses with narrow elongated vesicles, similar to GABAergic vesicles seen in other neurons, frequently occurred on terminals of primary afferents. These synapses provide a basis for known presynaptic inhibition of afferent input. Consistent with physiology, such inhibitors sometimes also contacted the postsynaptic targets of the primary afferents and sometimes received input from other primary afferents. Afferent terminals also received some input from profiles rich in large dense cored vesicles. Presumptive inhibitory input found on proximal dendrites of lateral giants provides a basis for known recurrent inhibition. However, similar inhibitory synapses that sometimes received local input from excitors of the lateral giants were also found distally mixed with excitatory inputs. These provide a basis for recently discovered distal inhibitory input following excitation and for tonic inhibition.

Afferent Pathways↗
PubMed1991

Morphine analgesia, tolerance and addiction in the cricket Pteronemobius sp. (Orthoptera, Insecta).

The escape reaction time (ERT) of the cricket Pteronemobius sp. from the heated box begins at 48 degrees and increases with temperature until 56 degrees C, beyond which there is no further increase. The ERT (2.2 +/- 1.39 s) from the hot box at 54 degrees C is used as a model for studying the analgesic effects of opiates. Results of the present paper show that the ERT did not change after injecting the insect in the abdominal haemocoel with 0.9% saline solution, but ERT increased when 0.32, 0.52 or 0.69 mg/g of morphine is injected in the same place. The maximum ERT increase is reached at 90 min after drug injection, and the drug effect disappears 3 h after the injection. At 90 min after drug injections, the dose of 0.50 mg/g of morphine produces 50% of ERT increase, and it is referred to as the median analgesic dose (D50). 1.05 mg/g of morphine produces an ERT longer than 30 s that results in an irreversible damage to the insect. Sixty-four micrograms/g of naloxone given in addition to D50 of morphine fully blocked the effect of morphine during its 3-h action. However, more than 64 micrograms/g of naloxone alone also increase the ERT in the cricket, similar to what has been described for vertebrates. Four daily morphine injections of D50 decreased ERT in such a way that, at the fourth day, the ERT is similar to the ERT produced by saline solution; i.e., tolerance is shown. The suppression of daily morphine injections of D50 during the fifth day produced a hyperresponse to vibration (big jumps) not shown in the case of the injections of saline solution; i.e., addiction is shown.

Analgesia↗
PubMed2006

Activation of a sensorimotor pathway in response to a water temperature drop in a teleost fish.

When common carp, Cyprinus carpio L., experience a rapid temperature drop, the cerebral blood volume is strongly reduced to dampen the temperature drop in the brain. Simultaneously, the preoptic area and pituitary gland are activated to launch whole-body adaptive responses. However, the preferred reaction of fish to a temperature change is an escape reaction, which implies activation of a sensorimotor pathway. Here, we used blood oxygenation level-dependent (BOLD)- and cerebral blood volume (CBV)-weighted functional magnetic resonance imaging (fMRI) to identify a sensorimotor pathway, during a 10 degrees C temperature drop in common carp. Transient activation was observed in the region where the sensory root of the trigeminal nerve enters the brain, and in the valvula cerebelli. In both regions, metabolic activity increased (increased deoxyhemoglobin content demonstrated by a decreased BOLD signal) within 30 s after the onset of the temperature drop, peaked after 2-3 min, and then decreased, even though the temperature continued to drop for another 2 min. These brain structures appear to respond to temperature change, rather than to the absolute temperature. Thus, during a temperature drop, the sensorimotor pathway consisting of the trigeminal nerve, the primary sensory trigeminal nucleus, the valvula cerebelli and some motornuclei, is active, in line with perception of temperature change in the buccal cavity, leading to motor activity for escape. This pathway operates in parallel to an acclimation pathway, which involves the preoptic area to pituitary gland pathway.

Animals↗
PubMed1985

Maze-escape learning and memory during rat ontogeny.

With the method of a simple automatic rectangular maze the development of escape reaction was studied in albino rats aged 3 weeks to 3 months as well as memory retrieval within 24 h and then after one month. Learning of escape improves sharply between the 3rd and 4th postnatal week, and then, with the exception of week 8, remains approximately on the same level. Memory retrieval up to 24 h is not significantly influenced by age or sex, but is best immediately after learning interval of 10 min and the poorest after 24 h, except the age of 5 weeks, where it is best in 3 and 6 h after learning. One-month retention of maze escape improves during development except in animals trained at the age of 6 weeks in which the level is lower than in all other investigated groups. One-month memory retrieval in animals taught at the age of 4 weeks is influenced by the time of the first retention test with the best values in animals tested for the first time after 3 h and poorest in animals tested after 24 h after learning. Animals trained at 5 weeks had a marginally better result after the one-month retention test in females, perhaps due to the influence of sexual maturation on memory traces. This was not observed in the other age groups. Attention is drawn to the different development of learning and memory of various types of conditioned reactions stemming from the difference in their complexity.

Analysis of Variance↗
PubMed1995

Delta opioid receptors: reflexive, defensive and vocal affective responses in female rats.

Ultrasonic vocalizations may be an expression of the affective pain response in laboratory animals. The present experiment compares the effects of morphine to the delta agonist, DPDPE (D-Pen2,D-Pen5 enkephalin) on a range of reflexive, behavioral and affective responses during an aggressive interaction. In experiment 1, naive female Long-Evans rats received morphine (0, 1, 3, 6, 10 micrograms ICV), or DPDPE (0, 30, 60, 100 micrograms ICV). In experiment 2, female rats were treated with naltrindole (1.0 mg/kg IP) 20 min before DPDPE (0, 60, 100 micrograms ICV). The following endpoints were measured: (1) latency to tail flick in response to heat stimuli; (2) high (33-65 kHz) and low (20-32 kHz) frequency ultrasonic and audible vocalizations; (3) defensive behavior; and (4) motoric activity. Following a brief exposure to attack, rats were threatened by the aggressor but protected from further attack by a large, wire mesh cage, thereby allowing for continued behavioral and vocal measurement without the risk of physical injury; video and audio recordings were made during the attack and then during a portion of the protected encounter (2 min). Morphine suppressed pain reactions varying in complexity from a spinal reflex, to an organized escape reaction, to an affective vocal response. The delta agonist, DPDPE, attenuated high frequency ultrasonic calling and tail flick responding. Defensive behaviors were also modulated by DPDPE at doses that had no effect on walking or rearing, indicating behavioral specificity. By contrast, doses of morphine that decreased defensive upright and escape also decreased motor activity. In female rats, morphine and DPDPE share a common profile of effects on a range of functional end-points, but DPDPE appears to modulate more selectively the reactions related to aversiveness without exerting sedative effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Analgesics↗
PubMedDate not supplied

[The differential effect of damage to the motor cortex on the precise reactions of avoidance and escape in dogs].

Effects of ablation of the forelimb area in the motor cortex on the precise lifting of this limb were studied. Even inaccurate avoidance reactions to the sound signal did not recover spontaneously. In the course of retraining irregular reactions of insufficient amplitude could be easily recovered but the precise reactions (both fast continuous and slow discontinuous) did not recover at least for half a year after the ablation. On the contrary, the fast precise escape reactions (to the shock applied to the "working" limb and eliciting its unconditioned flexion) remained essentially unchanged, i. a. the ability to stop movement in the correct (previously learnt) position persisted. The ability to fix position of the flexed limb retained but in was less perfect and did not improve. The ability to overcome unconditioned flexion (in order to perform discontinuous extensor escape reaction) was severely and continuously (for a year) decreased. Visually guided placings of the forepaw on a held out hand of an experimenter recovered essentially spontaneously and almost completely during a month.

Acoustic Stimulation↗