Different levels of complexity in the play-fighting by muroid rodents appear to result from different levels of intensity of attack and defense

Play-fighting in deer mice, Peromyscus maniculatus bairdii, prairie voles, Microtus ochrogaster, and montane voles, M. Montanus, was compared to that of laboratory rats, Rattus norvegicus. Play in rats appears more complex for two reasons: 1) more of the playful contacts elicit defensive behaviors, and 2) more of these defenses lead to counterattacks, and hence, role reversals between attackers and defenders. Neither high levels of defense, as shown by montane voles, nor high levels of counterattack, as shown by prairie voles, produce rat-like play-fighting. This only occurs when high rates of defense involving turning to face the attacker and counterattack are combined, as in rats. These two components are rarely combined together by deer mice, and so this species rarely exhibits rat-like play-fighting. Furthermore, playful counterattack appears to arise from playful attack, and not from an escalation of defense. These data suggest that the more complex forms of social play, such as play-fighting, have evolved, in part, via the escalation of defense in response to playful attack.     

Induction by reinforcer schedules.

Traditional strategies for determining whether a reinforcer schedule enhances the occurrence of an activity are reviewed and critically evaluated. A basic assumption underlying these strategies is that it is possible to isolate the effect of reinforcer intermittency on schedule induction. It is concluded that this is not, in fact, possible. An alternative approach is proposed that emphasizes the inductive effects of the reinforcer schedule as a unit and the effects of particular aspects of the reinforcer schedule (e.g., interreinforcer interval, repetition of the reinforcer, reinforcer magnitude).     

Relation between level of food deprivation and rate of schedule-induced attack

The relation between food deprivation and schedule-induced attack was investigated in four White Carneaux pigeons. Attack toward a mirror target was induced by a schedule of reinforcement in which 3-sec food presentations occurred at alternate intervals of 15 and 120 sec (multiple fixed-time 15-sec fixed-time 120-sec schedule). A continuous tone was presented during the 15-sec periods; it was absent during the 120-sec periods. Each pigeon was tested at 65, 80, and 95% of its free-feeding weight in ascending, descending, and ascending orders, respectively. Two relations were apparent; an inverse relation between body weight and rate of attack, and a tendency for rate of attack to increase during the experiment. Reduction or elimination of attack when the mirror was covered with brown paper for some sessions indicated that the results were due neither to changes in activity that might covary with weight nor to habituation to the experimental situation.     

Rank order in pairs of communally nursing female mice (Mus musculus domesticus) and Maternal Aggression Towards Conspecific Intruders of Differing Sex

This study examined social behavior between pairs of unfamiliar lactating females, with litters of the same age, at different periods after parturition (3, 7, and 17 days). Tests were generally followed by the formation of communal rearing nests, and subsequent maternal attack on intruders of differing sex was assessed. In all three intervals lactating females showed ritualized attack with formation of clear dominance-subordination relationships before combining litters into communal nests. The dominant females in 90% of cases started to retrieve alien pups into their nests. Agonistic behavior and communal nest formation were most rapid when pups were around 3 days old. Maternal attack on conspecific intruders was mainly displayed by the dominant lactating females. Male and female intruders were equally attacked (in terms of frequency and intensity of attack), but there was less such aggression when pups were around 17 days of age. Nevertheless the topography of biting attack employed against female and male conspecific intruders was different. Females were attacked using a strategy avoiding bites to the head and ventral surface (indicative of “offensive” behavior) whereas males were severely bitten on vulnerable body regions (indicative of “defensive” behavior).     

The assessment of individual “Aggressiveness” in pigeons by a variety of means

Pigeons attack or threaten animate and inanimate targets. The assessment of their aggressiveness was studied by exposing them in their home cages to three different stimuli: the experimenter's hand, a live pigeon, and a rear-projected conspecific image when the birds were exposed to intermittent access to food. A positive correlation between the hand test and live pigeon test was evident, but no relationship between either of these responses and the response to a pictorial image was observed. These results combined with other ethological observations cast doubts on the usefulness of schedule-induced responses to pictorial targets in the assessment of the individual aggressiveness in pigeons, but suggest that the hand test is an adequate and reliable procedure for such evaluations.     

The neural pathways mediating quiet-biting attack behavior from the hypothalamus in the cat: A functional autoradiographic study

Electrical stimulation of the region of the lateral hypothalamus produced a consistent form of quiet-biting attack behavior in cats. In one series of experiments, cats, implanted with electrodes from which attack had been elicited, were anesthetized and then were injected with a bolus of ¹⁴C-2-deoxyglucose at the same time as electrical stimulation was delivered through the attack electrodes. Brains prepared for X-ray autoradiography revealed that lateral hypothalamic stimulation activated the classical medial forebrain bundle pathway supplying the septal region, diagonal band, lateral preoptic area, and ventral tegmental region. Stimulation of quiet-attack sites in perifornical hypothalamus resulted in the activation of a much more extensive projection system which included the central and lateral tegmental fields of the midbrain and pons, and central gray region, as well as the structures described above. In a second series of experiments, ³H-leucine was placed into the region of the electrode tip from which attack was elicited in order to identify more precisely the pathways arising from that site. In general, tritiated amino acid radioautography replicated the ¹⁴C-2-deoxyglucose findings. In addition, the amino acid radioautographic data revealed the presence of extensive projections from perifornical hypothalamus to such pontine structures as the nucleus locus coeruleus, motor nucleus of NV , and the lateral pontine tegmental field. The functional connections between the lateral hypothalamic “attack region” and lateral preoptic zone were also confirmed by electrophysiological methods.     

Neuropharmacological aspects of adaptive pain inhibition in murine “victims” of aggression

This review outlines recent research on a subset of physiological responses in murine “victims” or aggression. In a typical resident-intruder paradigm, the detailed study of intruders has revealed that exposure to conspecific attack (and related stimuli) is associated with two forms of analgesia which appear to be integral components of the murine defensive repertoire. In response to intense/enduring attack, intruder mice display a profound, long-lasting and opioid-mediated analgesia. This reaction is highly correlated with defensive immobility and may function to reduce involuntary cues to further attack. In contrast, the inhibition of pain reactivity in mice tested immediately upon the display of defeat is less intense, shorter-lasting, non-opioid in nature and may function to facilitate active defenses such as escape. As this form of pain inhibition is also evident in intruders exposed to the scent of an aggressive male conspecific, a possible anticipatory defensive function linked to mechanisms of anxiety has been proposed. This hypothesis is supported by 1) the prevention of defeat analgesia by a range of antianxiety drugs (benzodiazepines, 5-hydroxytryptamine_1A [5-HT_1A] receptor agonists, and 5-HT₃ receptor antagonists) and 2) the effects of social defeat on behavior in the elevated plusmaze model of anxiety. These findings are discussed in relation to coping mechanisms in murine “victims” of aggression. © 1995 Wiley-Liss, Inc.     

Targets of attack and defense in play-fighting of the Djungarian hamster Phodopus campbelli: Links to fighting and sex

Analysis of the body targets attacked and defended during play-fighting by juvenile Djungarian hamsters Phodopus campbelli revealed that about 70% of all attacks were directed at the mouth. If successfully contacted, the mouth was briefly licked and nuzzled. The remaining playful attacks were gentle bites directed at the rump, and to a lesser extent, the top of the head. During serious fighting the top of the head and the rump are targets of attack, whereas the mouth is not. Licking and nuzzling the mouth was found to be a behavior performed by adult males at the beginning of sexual encounters. Therefore, play-fighting in juvenile hamsters cannot be thought of merely as a form of “mock fighting” since the principal target is seemingly sexual, not agonistic. The data also show that of the sexual body targets contacted, adult females are more likely to defend the mouth. In this way it is suggested that targets attacked and defended during juvenile play-fighting are derived from adult contexts in which such targets are defended. This hypothesis accounts for the prevalence of agonistic targets in the play-fighting of many species, and may provide a rationale for classifying those amicable targets that are competed for during play-fighting.     

Defensive reactions of “wild-type” and “Domesticated” wild rats to approach and contact by a threat stimulus

Selective breeding of wild rats over many generations on the basis of low or high defensive threat and attack to human approach and contact has produced highly polarized “domesticated” and “wild-type” animals. Because the selection procedure selectively involves these two defense patterns, and these clearly differ in the two groups, it is of interest to determine if other, nonselected, defensive behaviors to threat stimuli also change. “Domesticated” and “wild-type” rats of the thirty-fifth generation were run in a fear defense test battery (F/DTB) to systematically evaluate defensive behaviors to a variety of present threat stimuli. “Domesticated” rats showed reduced avoidance and slower flight speed to an approaching experimenter, reduced jump/startle response to handelap and dorsal contact, less vocalization and boxing to vibrissae stimulation or to an anesthetized conspecific, and reduced defensiveness to an attempted pickup by the experimenter. These results indicate that selective bi-directional breeding for defensive threat and attack to human approach and contact produces group differences in a variety of defensive behaviors, and in defensiveness to stimuli other than those on which the selection was based. © 1994 Wiley-Liss, Inc.     

Predicting who benefits from psychoeducation and self help for panic attacks

Self-help and psychoeducation have been identified as effective methods for delivering treatment, yet not everyone benefits from these brief interventions. Therefore it is clinically and economically useful to identify who is likely to require more intensive assistance. This paper develops a prognostic scale which predicts who will recover from panic attacks and who will require more assistance. Method: Random regression models were used to evaluate the relationship between predictive variables, baseline severity, and the rate of improvement in 117 people with DSMIV panic attacks who participated in a trial of a psycho-educational booklet, a self-help workbook, and brief group CBT over a 9-month period. ROC analysis was used to choose cut-off points on a scale made up of significant predictors. Results: Panic disorder and agoraphobia symptom measures were predicted by baseline social anxiety, and general mental health. There was no significant effect on the outcome for baseline depression or anxiety sensitivity. While general mental health (SF12 Mental Component scores) was predicted by the age at first panic attack, neuroticism, panic disorder and/or agoraphobia symptoms and a positive screen for alcohol use disorders. A prognostic scale based on simple additive scoring was equivalent to standard scores and significantly better than chance at predicting who would recover and who required face-to-face therapy. Conclusions: The prognostic scale may be used to guide the choice of psychoeducation, self-help or face-to-face therapy as the first step in stepped care.