Effects of genotype and postnatal experiences on activity, avoidance, shock threshold, and open-field behavior of rats.

Studied the effects of postnatal experience in 6 experiments on the activity, avoidance, shock threshold, and open-field behavior of 91 selectively-bred Ss from high-avoidance (RHA/Lu) strains and 93 from low-avoidance (RLA/Lu) strains. Significant differences were found between postnatal experiences in shuttle box activity, but strain differences were not significant. The high-avoidance Ss acquired avoidance learning significantly faster and had lower shock thresholds than the low-avoidance Ss. However, postnatal experience had significant effects on avoidance and shock threshold only in the high-avoidance Ss. No significant strain differences were found in open-field behavior, and the postnatal experience effects showed only higher order significant interactions. Results are discussed in the framework of quantitative genetics and a direct-action hypothesis of postnatal experience. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of unconditioned stimulus escape and avoidance in discriminative avoidance learning in the gerbil (Meriones unguiculatus).

Gave separate groups of male gerbils (N = 80) shuttle-avoidance training or classical trials (CS and UCS pairings) in a 100-trial session. The shock UCS was either escapable or inescapable (i.e., of fixed duration-.1-3.0 sec). CRs, intertrial interval responses, and observations of the Ss' reactions to each UCS were recorded. Avoidance learning emerged only in groups exposed to escapable shock or a brief inescapable shock. Based on both the observational data of the nature of the shock-elicited reactions and shuttle performance, it is concluded that response termination of the UCS is not necessary for shuttle-avoidance learning. Results are discussed in terms of a punishment theory of avoidance and the species-specific defense-reaction hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interaction among genotype, unconditioned stimulus, d-amphetamine, and one-way avoidance behavior of rats.

In the genetic analysis of avoidance learning, questions relating to the generality to other avoidance behaviors and the role of motivation were investigated in 61 RHA/Lu and 61 RLA/Lu rats. Significant differences were found in 1-way avoidance behavior of the strains selectively bred for 2-way active avoidance. In 6 experiments, these differences in 1-way avoidance either disappeared or were minimized to a great extent under the effects of dextroamphetamine. The experimental manipulation of motivation (i.e., unconditioned stimulus shock level equivalent to the unconditioned flinch, jump, and fleeing response measures) accounted for only part of the variation in avoidance learning of these strains. Results are discussed in the terms of inverted-–U arousal function and quantitative genetics. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Strain differences in avoidance conditioning as a function of the classical CS-US contingency.

Examined rates of shuttle box avoidance responding in 3 strains of rats as a function of classical and instrumental contingencies in 2 experiments. Ss were a total of 126 female albino Fischer, Lewis, and Long-Evans rats. In Exp I, during classical conditioned-stimulus-unconditioned-stimulus (CS-UCS) pairings in the absence of an avoidance contingency, there were large differences between the 3 strains in rates of anticipatory responding to the CS. The same pattern of differences was observed in Exp II when the avoidance contingency was added. None of the instrumental contingencies of CS termination, UCS termination, or the avoidance contingency differentially affected the strains. Classically elicited anticipatory responses and their compatibility with the required avoidance response were viewed as central factors in both the acquisition and maintenance of skeletal avoidance responses. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

DSP4 (N-2-chloroethyl-N-ethyl-2-bromobenzylamine), a new noradrenaline neurotoxin, and stimulus conditions affecting acquisition of two-way active avoidance.

Several CS and UCS variables known to affect the rate of acquisition of the 2-way active avoidance task were investigated in rats treated with the novel selective noradrenaline neurotoxin DSP4 (50 mg/kg, ip). 234 male Sprague-Dawley rats were used in 6 experiments. Although the DSP4 Ss did not demonstrate the linear relation between CS duration and avoidance acquisition to the same extent as controls, their avoidance performance was as drastically disrupted as that of the controls both by preexposure to the CS and by increasing levels of shock intensity. DSP4 Ss also evidenced fear retention for the shuttle box cues previously associated with inescapable shocks to as marked a degree as control Ss. Biochemical data indicated profound noradrenaline depletion in the cortex and hippocampus and a lesser depletion in the hypothalamus. Findings offer a behavioral characterization of the consistent DSP4-induced impairment of 2-way active avoidance acquisition. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interaction of an aversive Pavlovian conditional stimulus with aversively and appetitively motivated operants in rats.

Reports results of 5 experiments with a total of 168 male albino Sprague-Dawley rats. Presentation of an aversive CS produced an acceleration of free-operant Sidman shock-avoidance responding only if the CS had been paried with a relatively weak-shock UCS. Stimuli paired with a relatively strong UCS produced suppression of avoidance responding. With appropriate shock intensities, both suppression and acceleration were obtained. Responses of controls showed that this effect was not due to interactions between the operant response and UCS. In a within-S experiment, the same aversive CS produced suppression of an appetitive response (CER) and acceleration of avoidance. However, a CS which had produced avoidance acceleration did not suppress an appetitive operant. (23 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

US duration, conditioned acceleration, multiple CR measurement, and Pavlovian R-R laws in rats.

4 female Wistar albino rats were classically conditioned with a series of 4 different UCS (shock) durations and separately tested with unreinforced CS presentations during Sidman avoidance in a within-S Latin-square design. The ratio of CS rates to pre-CS rates (amplitude), the percentage of CRs (frequency), and the number of separate sessions of unreinforced CS presentations required to reduce the amplitudes to near zero (resistance to extinction) were all positively and monotonically related to UCS duration. Correlations between the 4 dependent variables were negative in the case of latency amplitude, latency frequency, and latency resistance to extinction, and positive in the case of amplitude frequency, amplitude resistance to extinction, and frequency resistance to extinction. (25 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Arousal explains difference in avoidance learning of genetically selected rat strains.

Manipulated task complexity differences in avoidance learning of genetically selected strains of rats under dextroamphetamine (1, 2, and 4 mg/kg, ip). 288 Ss from RHA/Lu, RLA/Lu, RCA/Lu, RHA by RLA, and RLA by RHA strains were studied. With decreasing levels of task complexity the differences in avoidance learning between the selectively bred strains decreased significantly. Under the lower levels of complexity the strains reversed their relative positions in avoidance learning. Results are discussed in terms of inverted-–U arousal function. The factors investigated in this study indicate that the differences in avoidance behavior of these lines of rats may be understood as deriving from genetically related different levels of arousal. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative regulation of Pavlovian fear conditioning: Unconditioned stimulus intensity, incentive shifts, and latent inhibition.

Conditional stimuli (CS) associated with painful unconditional stimuli (UCS) produce a naloxone-reversible analgesia. The analgesia serves as a negative-feedback regulation of fear conditioning that can account for the impact of UCS intensity and CS predictiveness on Pavlovian fear conditioning. In Exp 1, training under naloxone produced learning curves that approached the same high asymptote despite UCS intensity. Shifting drug treatment during acquisition had effects that paralleled UCS intensity shifts. In Exp 3, naloxone reversed Hall-Pearce (1979) negative transfer using a contextual CS, indicating that conditional analgesia acquired during the CS–weak-footshock phase retards acquisition in the CS–strong-footshock phase. Exp 5 used a tone CS in both a latent-inhibition and a negative-transfer procedure. Only negative transfer was blocked by naloxone. Therefore, negative transfer but not latent inhibition is mediated by a reduction of UCS processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

NMDA receptor antagonist MK-801 blocks learning of conditioned stimulus-unconditioned stimulus contiguity but not fear of conditioned stimulus in goldfish (Carassius auratus L.).

The blockade of learning of Pavlovian fear conditioning by the N-methyl-D-aspartic acid (NMDA)-receptor antagonist MK-801 was examined in 166 goldfish. In previously untrained fish, MK-801 blocked learning of a light-off or a tone conditioned stimulus (CS) paired with an electrical shock unconditioned stimulus (UCS). Pretraining on the light-off CS did not affect the rate of learning of the tone CS but protected the tone learning from disruption by MK-801. Switching from the light-off to the tone CS changed the identity of the CS but not its temporal contiguity with the UCS. Pretraining consisting of pseudoconditioning of the light-off CS did not protect subsequent tone learning from blockade by MK-801. Thus, the NMDA receptor functions are necessary for learning related to the temporal contiguity of the CS and UCS but not to the identity of the CS as a cue to the occurrence of the fearful effects of the UCS. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pavlovian analysis of avoidance conditioning in the goldfish (Carassius auratus).

Conducted 2 experiments in which 144 and 54 goldfish, respectively, were trained in a shuttlebox with light as CS and brief shock as UCS. Performance was measured in terms of "initial response" to the CS (at least 1 crossing of the hurdle on any trial) and-where the CS was not terminated by the initial response-in terms of "multiple response" to the CS (more than 1 crossing on any trial). The level of initial responding was as high in classically conditioned Ss (shocked on every trial) as in avoidance Ss, whether or not the CS was terminated by response, but lower in control Ss, yoked with the avoidance Ss, and lower also in punished Ss (shocked only if they responded). Multiple responding was negligible in avoidance Ss, but common in classically conditioned and in punished Ss. Results can be accounted for in purely Pavlovian terms, no reference to instrumental learning being required. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative learning modifies the shortening reflex in the semi-intact leech Hirudo medicinalis: Effects of pairing, predictability, and CS preexposure.

Three experiments addressed the importance of the inter-event relationships of contiguity and contingency for associative learning in the semi-intact leech. It was found that both of these relationships are important for the leech to acquire a learned association between a CS (touch) and unconditioned stimulus (UCS; shock). The learning can be extinguished if training is followed by explicitly unpaired presentations of the CS and UCS, which removes the contiguity between the stimuli. Learning is degraded by the introduction of unpredicted UCSs, as well as by unreinforced presentations of the CS (CS preexposure); both manipulations reduce the contingency between the CS and UCS. These results suggest that the associative process in both vertebrates and invertebrates share considerable functional similarity in the inter-event relationships important to learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Erratum to Satinder.

Reports an error in the article "Arousal Explains Difference in Avoidance Learning of Genetically Selected Rat Strains" by K. Paul Satinder (Journal of Comparative and Physiological Psychology, 1977, Vol. 91, No. 6, pp. 1326-1336), one line was printed incorrectly. On page 1331, the last line of Table 2 reads as follows: RNA/Lu oneway 193 280. The line should be changed to read as follows: RHA/Lu oneway 193 280. (The following abstract originally appeared in record 1978-22592-001) Manipulated task complexity differences in avoidance learning of genetically selected strains of rats under dextroamphetamine (1, 2, and 4 mg/kg, ip). 288 Ss from RHA/Lu, RLA/Lu, RCA/Lu, RHA by RLA, and RLA by RHA strains were studied. With decreasing levels of task complexity the differences in avoidance learning between the selectively bred strains decreased significantly. Under the lower levels of complexity the strains reversed their relative positions in avoidance learning. Results are discussed in terms of inverted--U arousal function. The factors investigated in this study indicate that the differences in avoidance behavior of these lines of rats may be understood as deriving from genetically related different levels of arousal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of a classical conditioning paradigm on hind-limb flexor nerve response in immobilized spinal cats.

Maintained 50 adult cats on Flaxedil after spinal transection at T-12 under ether anesthesia. Experimental Ss were classically conditioned by electrical stimulation of the exposed superficial peroneal nerve (CS), paired with cutaneous shock to the ankle of the same limb (UCS). The CR was the gross efferent volley recorded from the exposed deep peroneal nerve. Controls were divided into unpaired CS and UCS, CS-only, and UCS sensitization groups. Results show that the experimental conditions produced increases in amplitude of the gross efferent volley while unpaired CS and UCS, and CS-only control conditions produced no change or a decrease in amplitude. The UCS sensitization group showed that no sensitization was present at the intertrial intervals used in experimental conditions. (27 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differentiation of escape and avoidance responding in rats.

Examined escape and avoidance performance in 144 female Holtzman albino rats by factorially arranging immediate or postponed CS and UCS termination with shuttle or bar-press escape and avoidance responses. High levels of avoidance responding occurred only when the shuttle response (running) was both the escape and avoidance response, perhaps reflecting that rats are prepared to run but contraprepared to bar press when threatened by aversive stimulation. In addition, postponed UCS termination reduced avoidance performance drastically while CS termination conditions were without effect. Measures of UCS duration and clock terminations also indicated that immediate UCS termination was superior to postponed termination but additionally showed that this was so because postponed termination seriously impaired escape behavior. Results have particular relevance for how escape responses become anticipatory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavior-genetic-dependent self-selection of alcohol in rats.

Investigated self-selection of alcohol in 30 male and 30 female selectively bred rats: MNR/Har/Lu (f38), MR/Har/Lu (f33), RCA/Lu (F18), RHA/Lu (F18), and RLA/Lu (F18). In Exp. I, self-selection of alcohol of 3 concentrations was tested along with caloric-equivalent glucose solutions and distilled water. Exp. II investigated the simultaneous self-selection of 5, 10, and 20% alcohol solutions. In Exp. III effects of food deprivation on the self-selection of 10% alcohol and distilled water were studied. Self-selection of alcohol was related to the phenotypes of emotional reactivity and avoidance conditionability. Females consumed significantly larger amounts of absolute alcohol than males based on corrected body weight. Validity of sex differences is discussed. (30 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ontogeny and interdependence of genetically selected behaviors in rats: Avoidance response and open field.

Investigated in 2 experiments, ontogeny and interdependence of genetically selected avoidance and open-field behaviors in 6 genetic lines (e.g., MNR/Har/Lu, RCA/Lu), involving 1,018 rats, and 3 developmental models (longitudinal, cross-sectional, and generational). In selected lines, behaviors varied with age (either 21-, 35-, 70-, or 100 days of age), depending upon the genetic selection; in the control (random bred) line, no such effects were found. Between the lines selected for high (RHA) and low (RLA) rates of 2-way active avoidance, ontogenetic differences in the selected behavior emerged as Ss grew older, whereas between the lines selected for high (MR) and low (MNR) frequency of open-field defecation, the differences in the selected behavior were present at all stages of development. In Ss' unconditioned escape response to footshock, the differences were present at all stages. The relationship between avoidance response and open-field defecation (emotional reactivity) was not linear but suggestive of a curvilinear inverted-–U function. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Studies in early infant learning: Classical conditioning of the neonatal heart rate.

Three experiments demonstrated that human newborn heart rate level can be reliably modified through classical conditioning procedures. The theory of sensitization served as a frame of reference for Exps I and II, and drive reduction served for Exp III. In Exp I the delay, delay-trace, and control groups, with 10 2-day-old newborns in each, received 5 preconditioning trials of the CS alone, 16 conditioning trials with CS–UCS pairings differing for each group, and 5 extinction trials. Exp II was a replication of the 1st study and involved only the delay and delay-trace groups with 10 infants each. In both studies the delay group curves showed significant monophasic acceleratory responses during extinction. Results support the sensitization hypothesis (i.e., the CR occurring in the interstimulus interval was fashioned out of the response to the CS). In Exp III, the measure of conditioning was the response to the probe technique. 10 experimental Ss received preconditioning trials of nitrogen puff (UCS?) administered to the abdomen, followed by 10 CS–UCS? (500-Hz tone acetic acid) pairings with an interstimulus interval of 3 sec. 10 controls received the same design with a CS–UCS? interval of 40 sec. Analyses of the probe stimulus trials showed significant changes for the control group and none for the experimental group. The CS–UCS? pairings in the experimental group are interpreted as producing increased drive and adaptive damping of the heart rate response. Findings show that early learning may occur under a variety of conditions and that the results can be incorporated by different theories. (79 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Medial geniculate lesions block amygdalar and cingulothalamic learning-related neuronal activity

This study assessed the role of the thalamic medial geniculate (MG) nucleus in discriminative avoidance learning, wherein rabbits acquire a locomotory response to a tone [conditioned stimulus (CS)+] to avoid a foot shock, and they learn to ignore a different tone (CS-) not predictive of foot shock. Limbic (anterior and medial dorsal) thalamic, cingulate cortical, or amygdalar lesions severely impair acquisition, and neurons in these areas develop training-induced activity (TIA): more firing to the CS+ than to the CS-. MG neurons exhibit TIA during learning and project to the amygdala. The MG neurons may supply afferents essential for amygdalar and cingulothalamic TIA and for avoidance learning. To test this hypothesis, bilateral electrolytic or excitotoxic ibotenic acid MG nuclear lesions were induced, and multiunit recording electrodes were chronically implanted into the anterior and posterior cingulate cortex, the anterior-ventral and medial-dorsal thalamic nuclei, and the basolateral nucleus of the amygdala before training. Learning was severely impaired and TIA was abolished in all areas in rabbits with lesions. Thus learning and TIA require the integrity of the MG nucleus. Only damage in the medial MG division was significantly correlated with the learning deficit. The lesions abolished the sensory response of amygdalar neurons, and they attenuated (but did not eliminate) the sensory response of cingulothalamic neurons, suggesting the existence of extra geniculate sources of auditory transmission to the cingulothalamic areas.     

Flavor-illness aversions: Potentiation of odor by taste with toxin but not shock in rats.

Paired almond odor or saccharin taste as a single CS or as a compound CS for both a footshock UCS and a toxin UCS (LiCl) to test the generality of potentiation in male Sprague-Dawley rats. Extinction tests with the almond and saccharin components were then given. In single CS–toxin experiments, taste was more effective than odor, and after compound conditioning, the taste component potentiated the odor component. Conversely, in single CS–shock experiments, odor was more effective than taste, and after compound conditioning, no potentiation was observed. Instead, interference effects were observed. In Exps I and II, the addition of taste disrupted odor CS–shock conditioning, and in Exp III, odor interfered with taste CS–shock conditioning. Visceral feedback was apparently a necessary UCS for the potentiation of odor by taste. Data support the neural convergence and gating hypothesis of flavor aversion conditioning. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)