Effects of lesions of the gustatory neocortex on taste aversion learning in the rat.

In 5 experiments, 110 normal male Long-Evans hooded rats and 125 Ss with lesions of the gustatory neocortex (GN) were compared for their ability to learn aversions to taste cues paired with toxicosis. When the taste presentation was followed immediately by toxicosis, normal Ss and 8 Ss with lesions of the posterior (visual) neocortex learned aversions to sucrose, sodium chloride, quinine hydrochloride, and hydrochloric acid solutions. Ss with GN lesions learned aversions to all solutions except sucrose. In preference tests, all solutions were shown to be discriminable from water by both normal and GN-lesioned Ss. Under conditions in which a 6-hr delay separated taste presentation and toxicosis, normals again learned specific aversions to all 4 solutions, but Ss with GN lesions failed to learn specific aversions to sucrose, sodium chloride, and hydrochloric acid solutions. It was shown that the ability of Ss with GN lesions to learn aversions to sucrose and quinine depended on stimulus concentration. It is proposed that the data can be accounted for by postulating a change in the threshold for taste illness associations following GN lesions. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heredity and experience: Their relative importance in the development of taste preference in man.

Heritability estimates for sucrose, lactose, and sodium chloride taste preferences were uniformly low in a total of 311 pairs of monozygotic and like-sex dizygotic twins between 9 and 15 yrs of age. Black Ss preferred more concentrated solutions of all 3 tastants than did Caucasian Ss. This effect was independent of socioeconomic status in the total sample. Males preferred more concentrated solutions of sucrose and lactose than did females, but there were no sex differences in sodium chloride preference. The possibility that early intake experiences may play a role in the determination of enduring taste preferences in humans is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociation of spatial discrimination deficits following frontal and parietal lesions in monkeys.

Gave 40 rhesus monkeys dorsolateral prefrontal, posterior parietal, or inferotemporal lesions. 4 additional Ss served as unoperated controls. Ss then received 2 forms of spatial discrimination training, based on body position ("egocentric" cues) and on the position of an external referent ("allocentric" cues), respectively. On the former, a place discrimination reversal, frontal Ss were impaired but not parietals. On the latter, a landmark discrimination reversal, parietal Ss were impaired but not frontals; this result was also obtained on a test involving distance discrimination without reversal. Finally, the inferotemporals but not the frontals or parietals were impaired on a nonspatial object discrimination reversal. Results suggest that the 2 modes of spatial orientation, egocentric and allocentric, are related to frontal and parietal mechanisms, respectively. (18 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Taste as a dipsogenic stimulus.

Studied solution drinking in 50 male, nondeprived, Sprague-Dawley albino rats to determine how much animals will drink for reasons of taste alone. 4 different taste stimuli (sucrose, glucose, sodium saccharin, and sodium chloride) were used, each covering a wide range of concentrations. The same Ss were then retested after 16 hr. of water deprivation, and intakes under deprived and nondeprived conditions were compared. Results show that Ss ingested large volumes of sweet solutions in the absence of any need, and that water deprivation added only a small increment to the already high intakes of sweet solutions. Sodium chloride solutions, on the other hand, were ingested in relatively small quantities by nondeprived Ss, but water deprivation produced a large increase in intake. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heart rate and GSR concomitants of vigilance and arousal.

In an experiment with 16 male undergraduates, Ss receiving high shock were considerably more autonomically aroused than low shock Ss, as indicated both by an index of GSR, and by heart rate uncorrected for base level. When corrected, heart rate did not differentiate between Ss receiving high and low level shock. In a within Ss comparison, however, UCS temporal uncertainty generated lower corrected heart rate than UCS-certainty, and did so independently of shock level. It is unlikely that UCS-uncertainty was less anxiety arousing than UCS-certainty; indeed, GSR data suggest the contrary. The decrease in heart rate during UCS-uncertain trials is presumed to be a function of Ss' increased vigilance for uncertainty removing cues. The cognitive orientation toward environmental intake which such vigilance implies should, according to J. I. Lacey, be accompanied by cardiac deceleration. It is argued that such cognitive aspects of cardiac functioning are superimposed over gross cardiac responsiveness to autonomic arousal. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relationships between the determinants of performance in serial feature-positive discriminations.

Conducted 3 experiments using an appetitive behavioral observation procedure to investigate the effects of pre- and postdiscrimination treatments on learning and performance in serial feature-positive discriminations. Previous work suggests that performance in this discrimination is based on feature–UCS associations, feature–common element associations, and a conditional occasion-setting relation. Exp I examined the effects of prediscrimination reinforcement of the components of the discrimination. 26 male and 6 female Sprague-Dawley rats were assigned, in groups of 8, to 1 of 4 prereinforcement conditions (involving administration of a tone, a light, and a trace interval). Ss then trained on a serial feature-positive discrimination. Behavioral observations were recorded. Exps II and III investigated the effects of postdiscrimination nonreinforcement and reinforcement procedures on performance of established discriminative responding by 64 Ss. Results of the studies and of previous work are interpreted to show that the conditional occasion-setting relation may be independent of feature–UCS associations and may not depend on feature/common element associations. (61 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Function of the "onset of illness" in the preference changes of alloxan-diabetic rats.

144 male Sprague-Dawley rats were given access to saccharin or NaCl solutions as a conditioned stimulus (CS) at 1 of several times before and after injection with alloxan as an unconditioned stimulus (UCS) and were compared with controls (given UCS but no CS exposure) on their preference for the CS 7 days after the diabetes was well established. Results indicate that Ss exposed to the UCS at 1 or 2 hrs prior to the CS or at 1, 2, or 6 hrs following the CS all formed a conditioned aversion, whereas those with 6, 24, or 48 hrs between UCS and CS showed no greater aversion to the CS than controls. It is suggested that while the onset of alloxan diabetes can serve as the UCS for a conditioned taste aversion, the behavior of alloxan-diabetic rats towards saccharin does not depend upon this process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perception of species-specific contact calls by budgerigars (Melopsittacus undulatus).

In Exp I, 3 budgerigars were trained with operant techniques to discriminate examples of species-specific contact calls (5 male and 5 female). In Exp II, Ss were tested on vocalizations from 5 male and 5 female canaries. Ss showed an equivalent ability to discriminate and remember both budgerigar and canary calls. Additional tests (Exps III and IV) showed that both temporal and spectral cues were important in Ss' discrimination of species-specific calls. However, spectral cues occurring in the region of 2.0–4.0 kHz appeared to be critical for the discrimination. Results support the notion of a generalized, but highly sophisticated, perceptual learning system in the budgerigar for the processing of vocal signals. The perceptual and memory skills involved in this learning system are discussed. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acquired equivalence and distinctiveness in matching to sample by pigeons: Mediation by reinforcer-specific expectancies.

Assessed the ability of a reinforcer to mediate an association between 2 stimuli that independently predict the occurrence of that reinforcer (acquired equivalence of cues). In Exp I, 12 male White Carneaux pigeons were trained on shape (plus and circle) and color (red and green) matching-to-sample tasks. Correct responses were systematically reinforced with corn on some trials and wheat on others to establish associations between 1 stimulus from each task and a "common" outcome. Following training, Ss were transferred to a symbolic matching-to-sample task wherein a stimulus from one training task was presented as the sample, and the stimuli from the other training task were presented as comparisons. In the 1st session, experimental Ss made significantly more correct responses than controls (i.e., Ss "matched" stimuli previously associated with a common outcome). Exp II with 18 Ss replicated this acquired equivalence effect and controlled for food preference. Delayed matching-to-sample training demonstrated enhanced memory performance for Ss exposed to different reinforcement contingencies, but this effect was confined to the shape task. Results indicate that a reinforcer can serve as the basis for organizing otherwise unpaired predictive cues in memory and that animals will selectively use differential expectancies as cues for solving complex discrimination tasks, depending on the difficulty of the discrimination. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unconditioned stimulus rehearsal and the retention and enhancement of differential "fear" conditioning: Effects of trait and state anxiety.

In 2 experiments, the effect of anxiety on the cued-unconditioned stimulus (UCS) rehearsal phenomenon was investigated (T. Jones and G. C. L. Davey, see record 1990-18981-001). In Exp 1, postconditioning rehearsal of the UCS resulted in an increase in CR strength during extinction, but only in Ss with high levels of trait anxiety. An induced mood procedure was used in Exp 2, and a postrehearsal increase in CR strength was found in Ss who had undergone induced somatic anxiety but not in Ss who had undergone induced worrying or who underwent a neutral induction procedure. In both experiments, the increase in CR strength following UCS rehearsal was associated with inflated ratings of the aversiveness of rehearsing the UCS. These results are discussed in terms of the ways in which anxiety might influence UCS rehearsal and facilitate physiological CRs to the CS. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interhemispheric competition of antagonistic memories in the rat.

2 competing solutions to a black-white discrimination were stored separately in the 2 hemispheres of 48 albino rats under KCl-induced unilateral spreading cortical depression. When tested with both hemispheres intact in an unresolvable conflict situation, Ss showed disordered behavior and regressed to innate types of behavior (e.g., exploration and position responding). The results indicate that when there was no intermediate solution available and the 2 memories were of equal potency, Ss behaved in a more primitive fashion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Facial expressions and social responsiveness of blind monkeys.

Conducted 3 experiments with 5 blind and 5 sighted crab-eating monkeys (Macaca fascicularis), and their offspring to (a) test the role of auditory and visual information in attraction of an infant to its mother, (b) determine whether blind infants preferred their mothers to a mother from another group when both females were fully sedated, thus eliminating auditory and visual cues, and (c) assess the frequency and character of social interactions and facial expressions of blind Ss. Results of the 3 experiments show that tactual and perhaps auditory cues maintain the social affinity of blind juvenile monkeys. Olfactory discrimination of individuals was also tested, but not demonstrated. Facial expressions were essentially normal in form, but in some cases they occurred at different frequencies than those of sighted animals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retention and acquisition of classical trace conditioned responses by rabbits with hippocampal lesions.

Examined the effects of dorsal hippocampal lesions on retention of classical trace conditioned responses (CRs) using the rabbit nictitating membrane preparation. In Exp I, 18 New Zealand albino rabbits were trained to criteria and then lesioned either in the cortex or in the hippocampus and the cortex. Hippocampal damage had no effect on the retention of responses but produced significantly longer onset latencies. A control group of hippocampal Ss acquired CRs at least as quickly as the prelesion Ss and exhibited longer response onset latency. Exp II, with 24 Ss, evaluated the performance of hippocampal-lesioned Ss in classical trace conditioning with either a low-intensity periorbital shock or a corneal air puff as the unconditioned stimulus (UCS). Hippocampal Ss successfully acquired CRs under both conditions but exhibited an alteration of response onset that depended on the form of the UCS. Hippocampal Ss displayed shorter response onset in the air-puff condition and longer response onset in the shock condition. Cortical Ss consistently timed responses regardless of the UCS. Findings suggest that the hippocampus modulates temporal characteristics of learned behavior. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of potassium depletion on mineral appetite in the rat.

Studied potassium appetite in normal female Sprague-Dawley rats and in rats in which the total body potassium had been reduced by 15-20%. Potassium depletion resulted in increased ingestion of solutions of NaCl, KCl, CaCl2, and quinine sulphate in concentrations that were unacceptable to normal Ss. The amount of potassium ingested was related to the degree of potassium depletion and repletion was usually completed within 24 hr. when potassium was offered. Potassium-depleted Ss also drank large quantities of aversive concentrations of sodium chloride. This was preferred to potassium chloride and its ingestion appeared to be unrelated to need. The appetite state was reversed by prior intragastric repletion with potassium but not with sodium salts. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Judgements of discrimination as a function of group experience and contextual cues.

The personal/group discrimination discrepancy (PGDD) refers to the tendency to report more discrimination against one's group than oneself. The authors demonstrated that the magnitude of both personal and group discrimination judgments depend on group experience and cue availability in the judgment context, using college students as Ss. For men, who have relatively little experience with gender discrimination, the addition of contextual cues that highlighted workplace discrimination produced lower estimates of both personal and group discrimination. For women, who are familiar with discrimination in general and workplace discrimination in particular, contextual cues produced higher estimates of group discrimination, but lower estimates of personal discrimination. The authors contend that these differences reflect realistic assessments by participants of their group's experiences with discrimination. Implications for conceptualizing the PGDD are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of recognition of emotions: Children's reliance on situational and facial expressive cues.

Examined the influence of nondiscrepance and discrepance between situational and expressive cues on children's emotion recognition. Videotaped episodes in which actors portrayed emotions were presented to 96 4–8 yr old girls. When cues were nondiscrepant, Ss were better at all ages in recognizing happiness, fear, sadness, anger, and disgust than shame and contempt. This was interpreted as reflecting differences in complexity of emotions. When cues were discrepant, Ss preferred cues depicting the most recognizable emotion—that is, cues of simple emotions in preference to cues of complex emotions, and emotional cues in preference to neutral cues. Contrary to expectations, Ss did not rely on more salient cues in preference to less salient cues. Ss' responses to questions regarding the perceived cues reflected a developmental trend from noticing only 1 type of cue to considering both situational and expressive cues. This is interpreted as reflecting a development from centration to decentration. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Occasion setting with simultaneous compounds in rats.

Investigated rats' solutions of simultaneous feature positive discriminations (XA+, A–). When X was a visual cue and A was an auditory cue of moderate intensity, the rats solved the discrimination by associating X with the food unconditioned stimulus (UCS) and ignoring A. But when X was a visual cue and A was a loud auditory cue, the rats solved the discrimination by using X to set the occasion for responding that was based on associations between A and the UCS. The use of these two strategies was apparently determined by the perceptual (intensity) characteristics of A during learning of the discrimination: It was not affected by A's conditioning history prior to discrimination training, nor by A's intensity during a posttraining test. The results were discussed in terms of recent theories of occasion setting and generalization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Alteration of classically conditioned heart rate by operant reinforcement in monkeys.

Ran 6 adolescent male rhesus monkeys alternately on classical conditioning and on operant heart rate training schedules. The classical unconditioned stimulus (UCS) was identical to the operant negative reinforcement. After operant training, some Ss changed their heart rate responses to the classical conditioned stimulus (CS). When both the operant and the classical schedules were in force simultaneously, all Ss changed their previous heart rate responses to the classical CS without significantly changing their blood pressure responses to this stimulus. The changes in heart rate response to the CS sometimes persisted long after the operant schedules were no longer in force. These results show that a classically conditioned response can be altered by operant reinforcement, and they suggest that the classical UCS actually may be an operant reinforcer. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of septal area damage and base-line activity levels on conditioned heart-rate response in rats.

Exp. I subjected 7 unrestrained male Long-Evans rats with septal area lesions and 8 nonoperated controls to Pavlovian heart-rate conditioning with footshock as the UCS. Experimental Ss displayed lower degrees of tachycardia to both the CS and UCS than did controls, but there were no significant differences in amount of skeletal movement. In Exp. II, 6 control and 6 septal-damaged Ss received CS-shock pairings while lever pressing for food and while not lever pressing. There was no difference in conditioned suppression, but less conditioned tachycardia was again seen in experimental Ss, indicating dissociation between the 2 measures of conditioning. All Ss exhibited greater tachycardia during the non-lever-pressing condition, illustrating the effect of base-line activity on conditioned heart-rate responses. (24 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A multivariate approach to the analysis of genetic and septal lesion effects on maze performance in mice.

Reports univariate and multivariate analyses concerning spatial discrimination behavior of Binghamton heterogeneous (HET), C57BL/6J, and RF/J mice that had received either septal lesions or control surgery (N?=?80). In acquisition of an appetitively motivated T-maze task, lesions impaired HET but improved RF performance relative to their respective controls. When Ss with lesions were reversed on a spatial discrimination acquired in a 17°C water maze, their performance was worse than control Ss; the magnitude of the deficit was strain-specific. Measures of reactivity to handling suggested that HET and RF Ss with lesions were more reactive than their controls; there was no such difference in C57 Ss. Multivariate approaches broadly corroborated the importance of complex Gene?×?Environment interactions that mold experience and thus behavior. They appeared to give some potentially important insights into the differential "behavioral profiles" of Ss with lesions and control Ss of the 3 genotypes; for instance, reactivity to handling and repeated error measurements were important variables in discriminating among the groups in both learning tasks. Thus, multivariate techniques should be considered as useful, additional tools for the development and evaluation of explanatory theories regarding functions of CNS regions. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)