The time course of learned helplessness, inactivity, and nociceptive deficits in rats

Lick-suppression tests were used in seven experiments to assess the transsituational transfer of fear in the learned helplessness paradigm. Two sources of fear combined to suppress test drinking in inescapably shocked rats. A situational odor was strongly associated with shock pretreatments and mediated the transfer of conditioned fear during testing. Fear of the pretreatment odor was greater following inescapable shock than after escapable shock or restraint. This conditioned suppression was retained for at least 72 h after pretreatment. Neophobia was enhanced as a second, nonassociative reaction to inescapable shock. Unconditioned fear was augmented by a novel odor in the test context, but otherwise was weak and dissipated within 72 h. However, neophobia was necessary for differential conditioned suppression in inescapably shocked rats. The pretreatment odor elicited fear only when tested in a novel context. Initial habituation to the test apparatus reduced conditioned fear. These data provide additional evidence for odor-mediated transfer of helplessness. Conditioned fear and neophobia are discussed in relation to recent anxiety interpretations of the phenomenon.

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confidence: 99%

Section: Methodsmentioning

confidence: 99%

Conditioned fear and neophobia following inescapable shock

Minor¹

1990

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confidence: 96%

“…The presentation of inescapable shock has been shown to interfere with the ability of a variety of speciesto later learn a novel response to escape shock (e.g., Anisman, Suissa, & Sklar, 1980;Maier, Albin, & Testa, 1973;Overmier& Seligman, 1967) or to' learn an appetitive operant task (Rosselini, 1978). Transituational deficits resulting from inescapable shock have also been found in tests of nonassociative or unlearned behaviors, such as nonreinforced shuttlebox running (e.g., Maier, Coon, McDaniel, Jackson, & Grau, 1979) and tail flicks to nociceptive stimuli (e.g., that shock-elicited aggression reflects attack or aggressive tendencies has been vehemently challenged on a number of grounds by Blanchard and his col- . First, the specific behaviors typically seen during shock-elictied aggression are very similar to those shown by colony intruder rats under attack and do not resemble the fighting pattern of a dominant male resident in an established colony.…”

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confidence: 99%

Influence of shock controllability by dominant rats on subsequent attack and defensive behaviors toward colony intruders

Williams

1982

Thirty colonies, each consisting of a female and two male adult albino rats, remained intact for an a-week period. Naive conspecific intruders were then introduced into each colony for a 10-min test for 5 consecutive days. Videotapes of the tests were scored for aggressive and defensive behaviors. In every colony, aggression was greatest for a single alpha male. The alpha rats were randomly given one of three treatments: wheel-turn escape training, inescapable yoked shock, or restraint without shock. The alpha rats were then returned to their colonies and an intruder test was given 26 h later. Significant decreases in aggressive responses and increases in defensive behaviors occurred in the alpha yoked group but not in the other alpha groups. The nonalpha colony partners of the alpha yoked rats showed the opposite changes following the treatment. A final intruder test 72 h later revealed that the deficits in aggression of the alpha yoked group were still present but that the behaviors of most of the other groups were beginning to return to their respective pretreatment levels. These findings were discussed in terms of the concept of learned helplessness and alternative theoretical explanations.The finding that prior exposure to inescapable, as opposed to escapable, shock can have dramatic behavioral and physiological consequences has generated much research and theoretical interest (cf. Maier & Seligman, 1976;Sklar & Anisman, 1981). The presentation of inescapable shock has been shown to interfere with the ability of a variety of speciesto later learn a novel response to escape shock (e.g., Anisman, Suissa, & Sklar, 1980;Maier, Albin, & Testa, 1973;Overmier& Seligman, 1967) or to' learn an appetitive operant task (Rosselini, 1978). Transituational deficits resulting from inescapable shock have also been found in tests of nonassociative or unlearned behaviors, such as nonreinforced shuttlebox running (e.g., Maier, Coon, McDaniel, Jackson, & Grau, 1979) and tail flicks to nociceptive stimuli (e.g., that shock-elicited aggression reflects attack or aggressive tendencies has been vehemently challenged on a number of grounds by Blanchard and his col- . First, the specific behaviors typically seen during shock-elictied aggression are very similar to those shown by colony intruder rats under attack and do not resemble the fighting pattern of a dominant male resident in an established colony. Second, the forelimb movements that have typically been interpreted as "striking" during shock-elicited aggression have been shown to partially represent uncontrolled movements elicited by the footshock when the forelimbs are suspended or when the rat is engaged in defensive boxing. Third, the majority of the bites and wounds made by rats during elicited aggression are directed at the conspecific's head region. This target area is far more typical of the defensive behavior of an intruder than the attack fighting of a dominant male in a colony setting.In addition to being a questionable measure of attack behavior, elicited aggressi...

“…In mice and rats, experiencing inescapable shock has been shown to interfere with the subsequent acquisition of escape responses (e.g., Anisman, Suissa, & Sklar, 1980), discrimination learning (Jackson, Alexander, & Maier, 1980), and appetitive operants (e.g., Rosellini, 1978;Rosellini, DeCola, & Shapiro, 1982). Transituational deficits produced by inescapable shock have also been found in tests of nonassociative or unlearned responses, such as nonreinforced shuttlebox running (Maier, Coon, McDaniel, Jackson, & Grau, 1979), shock-elicited fighting (Maier, Anderson, & Lieberman, 1972), general activity , and specific forms of exploratory behavior (e.g., Bruto & Anisman, 1983). In addition, inescapable shock has been found to result in opioid-and nonopioid-mediated analgesia to nociceptive stimuli (see Maier et al, 1983, for a review of this literature), and to induce increases in corticosteroids and acetylcholine and decreases in norepinephrine, dopamine, and serotonin (e.g., Anisman, This research was supported by USPHS Research Grant lROlNH4381S-{)1.…”

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confidence: 95%

Effects of repeated defeat by a dominant conspecific on subsequent pain sensitivity, open-field activity, and escape learning

Williams

Lierle

1988

Male rats were tested as intruders for 25 consecutive days in colonies that had either aggressive (i.e., alpha) or nonaggressive conspecific residents. Alpha-defeated intruders, in contrast to nondefeated rats, showed more defensive behavior, less gain in body weight, and received more bites during the course of these sessions. Tail-flick tests, using a heat source, revealed that both groups of intruders showed comparable sensitivity/reactivity to pain, and there was no evidence of analgesia as a function of resident encounters. Immediately after the last intruder session, all subjects were tested for exploratory activity in an open-field apparatus with the odors (i.e., soiled bedding) from the alpha colonies present. Defeated intruders showed significantly less locomotion, in terms of the number of grid crossings, than nondefeated rats. Twenty-four hours later, randomly selected subgroups of defeated and nondefeated subjects were briefly exposed, without being defeated, to aggressive colonies, and all rats were then retested for activity with alpha odors present. Previously defeated intruders were again less active, and the colony-exposure treatment suppressed the activity of defeated, but not nondefeated, subjects. Finally, 24 h after another resident-intruder session, both groups of intruders showed comparable FR 1 escape performance in a shuttlebox with alpha odors present, but the defeated rats failed to learn a subsequent FR 2 escape task. The findings of this experiment are discussed in terms of the concept of "learned helplessness," the effects of ethological stressors, and the authors' stress-coping-fear-defense (SCFD) theory.Numerous investigators have shown that repeated exposure to a laboratory stressor, such as electric shock, produces alterations in behavioral and neurophysiological processes. In mice and rats, experiencing inescapable shock has been shown to interfere with the subsequent acquisition of escape responses (e.g., Anisman, Suissa,