Septal lesions in rats produce reversal deficits in a simultaneous visual discrimination.

Trained 54 rats with septal lesions and their operated controls on a 2-choice simultaneous brightness discrimination problem and its reversal using a correction procedure in a maze with 4 sequential choice points. Rats with septal lesions were deficient in the reversal of this brightness discrimination. However, this deficit was seen only in a measure of repeated errors and was considerably altered by forced preexposure to selected cues involved in discrimination. Thus, perseveration was seen, as measured by repeated errors, even though rats with lesions reached criterion in the same number of trials as operated controls. Findings emphasize the critical nature of stimulus conditions, response measures, and the history of the animal in determining the effects of brain damage on behavior. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enhanced cue function of olfactory stimulation in mice with septal lesions.

Trained a total of 121 male hybrid normal mice and mice with septal lesions on a go-no-go discrimination task (multiple fixed interval of 15 sec, 15-sec extinction schedule) in 4 experiments. When the discrimination stimulus (the one which indicated to the S whether responding at the end of the interval would be reinforced) was a pellet of food (delivered at the start of the interval) or odor of food or non-nutritive substance (present throughout the 15-sec interval), acquisition of septum-damaged mice was enhanced. These lesions did not, however, alter performance when the discrimination was cued by a buzzer or flashing light. Results suggest that septal lesions produce an increased reactivity to olfactory stimuli and to stimuli associated with the delivery of food reinforcement. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of context manipulation on memory and reversal learning in rats with hippocampal lesions.

Conducted 3 experiments with 83 male Long-Evans rats to investigate (a) the memory of hippocampus-damaged Ss, and (b) their ability to modify response strategies in relation to the influence of familiar contextual cues. In Exp I, groups of hippocampal and control Ss learned a simultaneous discrimination habit and were subsequently tested for its retention under variable contextual conditions. All groups recalled the discrimination response to an equally high level when testing conditions were constant throughout, but the hippocampal group showed impaired memory when contextual stimuli at recall testing did not conform to those of original learning. Results of Exp II indicate that the hippocampal impairment was not simply the result of introducing novel stimuli. In Exp III, Ss were administered a reversal learning task with contextual stimuli varied between the 2 tests. The typically observed impairment of hippocampal Ss on this task was reduced by contrasting contextual conditions. Results are seen to support a context-retrieval interpretation of hippocampal function. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of behavioral deficits caused by lesions in septal and ventromedial hypothalamic areas of female rats.

41 female Holtzman rats with lesions in ventromedial hypothalamic (VMH) area and 37 Ss with lesions in septal area were compared with 30 normal Ss for passive-avoidance performance (Exp I), reversal learning (Exp II), and spontaneous alternation (Exp III). Lesions in both septal and VMH areas produced a deficit in passive-avoidance performance, a greater number of errors in reversal learning, and reduced spontaneous alternation in a -maze. The qualitatively similar behavioral deficits produced by septal and VMH lesions suggests that at least part of the functions of both of these areas may overlap in a single system. An attempt was made to identify such a functional system, and an explanation for the behavioral deficits produced by VMH damage was offered. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Performance and motivational deficits of helplessness: The role of motivational orientations.

Examined the hypothesis that the effect of failure feedback in producing learned helplessness would depend on the motivational orientation of a child. 53 4th–6th graders completed a scale of intrinsic vs extrinsic orientation in the classroom and were randomly assigned to success, failure, or control conditions, with the restriction that an approximately equal number of Ss with different motivational orientations were assigned to the different conditions. Extrinsically motivated Ss were predicted to exhibit performance decrement following a failure experience, whereas the opposite was predicted for intrinsically motivated Ss. Success feedback was predicted to enhance subsequent performance only for the intrinsic group. Following success, failure, or no feedback on an activity reflecting spatial skills (an incomplete picture task), Ss' performance on an activity tapping different skills (i.e., anagrams) provided by a 2nd experimenter served as the primary measure of helplessness. Ss' intrinsic motivation in performing the incomplete picture task, a similar task (embedded figures) and a dissimilar task (dots-to-dots) was also examined. Results support the predictions on both performance and intrinsic motivation measures. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Maternal behavior of mice with cingulate cortical, amygdala, or septal lesions.

Evaluated nest building, pup retrieving, and pup survival and growth in 11 primiparous female CF-1 strain mice and in 36 others with cingulate cortical, neocortical, amygdala, or septal lesions. Ss with neocortical or amygdala lesions showed little or no deficits in maternal behavior. Ss with septal lesions were severely impaired in all aspects of maternal care. These did not build nests, showed a variety of aberrant behaviors during pup retrieving, and their pups died or gained significantly less weight than those of controls. Ss with cingulate cortical lesions retrieved pups more slowly than controls, and retrieving deficits were correlated with the extent of retrograde degeneration found in the anterior thalamic nuclei. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Opposite effects of lateral septal LTP and lateral septal lesions on contextual fear conditioning in mice.

The effect of fimbrial high-frequency stimulation (HFS)-induced long-term potentiation (LTP) in the lateral septum (LS) on contextual fear conditioning was studied in mice. Mice were conditioned for fear toward a novel context through the use of footshocks. The 1st experiment showed that pretraining HFS reduced significantly conditional freezing to contextual stimuli. The 2nd experiment was designed to determine whether the reduction of freezing produced by fimbrial HFS resulted from LTP in the LS rather than from LTP in other brain structures. Accordingly, mice with lesions of the LS were used and submitted to the same protocol as in the 1st experiment. Results showed that LS lesions completely abolished the impairing effect of fimbrial HFS and, as a whole, potentiated the freezing response. These data suggest that contextual fear conditioning is strongly modulated by the level of hippocampal–LS synaptic neurotransmission. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Studying personality in the context of an advanced motivational psychology.

The theoretical advance in motivational psychology has exposed flaws in the conceptual foundation of classical test theory as applied in studying personality. Computer simulations of behavioral expression of individual differences in personality based on new motivational principles, the dynamics of action, have shown that the validity of thematic apperceptive measures of motives does not depend on reliability; and correlations among different behavioral expressions of the same trait are expected to be quite modest even prior to consideration of measurement error. These findings resolve 2 long-standing puzzles in the study of personality. The prospects of finally appraising the validity of factor analysis as a method of discovery, and of defining the appropriate relationship between basic theory about psychological processes and the theory of psychological measurement are discussed. (72 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impaired reversal but intact acquisition: Probabilistic response reversal deficits in adult individuals with psychopathy.

The performance of adult psychopathic individuals on a novel response reversal task involving 2 reward-punishment contingencies (100-0 and 80-20) was investigated. In line with predictions, adults with psychopathy presented with impairment on the response reversal component but not on the acquisition component of this task. This selective impairment for response reversal was seen for both reward-punishment contingencies and was related to the tendency of individuals with psychopathy to be less likely to stay with a rewarded correct response to a stimulus on the subsequent presentation of that stimulus. Results are discussed with reference to current models of the development of psychopathy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral deficits in groups with cerebral vascular lesions.

Established 3 groups of patients with cerebrovascular disease (right hemisphere, left hemisphere, or generalized involvement) by matching 15 triads for age, sex, education, and duration of diagnosed cerebrovascular disease. Intergroup and intragroup comparisons were made of results on a large battery of measures, including psychometric intelligence, motor strength and speed, psychomotor performance, and sensory functions. Tests given included halstead's finger tapping test, halstead's tactual performance test, and wechsler-bellevue, form i, verbal and performance iq values. Significant differences were found between groups with lateralized lesions, whereas the group with generalized involvement tended to occupy an intermediate position. The group with left cerebral damage had a significantly lower verbal than performance iq, whereas this relationship was reversed in the group with right cerebral damage. Motor, psychomotor, and sensory functions were consistently impaired on the side contralateral to the damage hemisphere for the groups with lateralized lesions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Medial septal lesions in rats produce permanent deficits for strategy selection in a spatial memory task.

Rats with medial septal (MS) lesions have been shown to consistently use a stereotypic response strategy rather than a nonstereotypic spatial learning strategy when solving a radial maze task. The present study examined the long-term effects of MS lesions on spatial memory performance to determine whether MS lesions permanently impair rats from using a nonstereotypic strategy. Male rats, initially trained on a radial maze, were given either MS or sham surgeries and were subsequently retested on the maze. Consistent with previous studies, all Ss with MS lesions used a stereotypic strategy during the postoperative retest. However, when placed through a series of retraining phases that required the S to use a nonstereotypic strategy to solve the task, none of the MS Ss could solve the task. These results indicate that lesions of the MS produce permanent spatial memory deficits that cannot be restored through extensive behavioral training. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparative learning and memory deficits following hippocampal and caudate lesions in mice.

Examined the effects of hippocampal, caudate, combined hippocampal-caudate, and sham lesions on the passive avoidance and active escape performances of groups of female CF1 mice. Bilateral hippocampal or caudate lesions produced similar impairments of passive-avoidance retention 1 day after training in Ss operated upon 1 day prior to training. Hippocampal and caudate lesions similarly facilitated active-escape retention. When surgery was performed immediately after training, hippocampal or caudate lesions each impaired both passive-avoidance and active-escape retention 1 day later; no retention deficits were observed when surgery was performed 1 hr. after training. When surgery was performed immediately after training and passive-avoidance retest was conducted 1 hr. later, only hippocampal lesions impaired retention. These and other data suggest the mediation of different neuroanatomical substrates for short- and long-term memory and different processes for storage and forgetting. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Factors underlying deficient passive-avoidance behavior by rats with septal lesions.

Analyzed passive-avoidance behavior in male Holtzman rats (N = 83) with septal lesions in 5 experiments. Results reveal 2 independent sources of the deficit in retention of passive-avoidance responding. One factor, increased responsiveness to positive reinforcement, caused a persistent deficit in passive-avoidance retention which could not be alleviated by previous training on a different passive-avoidance task. A 2nd factor, described as a temporary defect in response inhibition, produced a transient deficit in passive-avoidance retention which could be alleviated by prior training on another passive-avoidance task or continued testing on the same task. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The failure of context shifts to alter the recognition of faces: implications for contextual deficits in amnesia

The effects of contextual changes were examined in a group of divers performing a test of face recognition. No evidence was found that the shift from above to below water, or vice versa, disrupted recognition. The fact that the same test of visual recognition is sensitive to amnesic subjects poses a challenge to certain versions of the contextual deficit theory of amnesia.     

Attenuation of gastric lesions by psychological aspects of aggression in rats.

In a study with 80 male albino rats, Ss that fought with each other in response to electric shock showed reduced gastric lesions in comparison with Ss that received the same shocks alone so that fighting behavior did not occur. Also, gastric lesions were similarly reduced in Ss that fought even though they could not physically contact one another because of a barrier between them. In this case, the "protective" effect of fighting derived from the release or display of fighting behavior and did not require physical combat. A 2nd experiment with 48 rats showed that Ss that received shock together but did not engage in fighting behavior showed no reduction of gastric lesions, so that the protective effect of fighting was not an artifact of Ss receiving shock together. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hippocampal lesions cause learning deficits in inbred mice in the Morris water maze and conditioned-fear task.

This study examined the effect of hippocampal lesions on acquisition of the Morris water maze and conditioned-fear task in inbred mice. C57BL/6J, DBA/2J, and B6D2F1 hybrid mice were given hippocampal lesions or sham surgery and then tested. The lesioned C57BL/6J and B6D2F1 mice failed to learn the Morris task relative to sham-operated controls, and no DBA group learned the task. In the contextual component of conditioned fear, lesions decreased freezing in all strains. But the lesions only affected freezing to the conditioned stimulus in the DBA/2J and B6D2F1 strains. These data demonstrate that C57BL/6J and B6D2F1 mice use the hippocampus to solve the Morris water maze and conditioned-fear task, and the DBA mice use the hippocampus, to some degree, in the conditioned-fear task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attenuation of cycloheximide-induced amnesia in mice with strychnine sulfate.

Conducted 2 experiments to determine the effectiveness of strychnine sulfate in attenuating the amnesia induced in mice by small doses of cycloheximide (CYC). Previously, reversal of CYC-induced amnesia by catecholamine agonists has been taken as evidence that protein synthesis inhibitors induce amnesia via an inhibition of catecholamine synthesis. In Exp I, 220 male C57/BL 6J mice (aged 8–20 wks) were taught passive avoidance and received injections of saline, strychnine sulfate, or dextroamphetamine sulfate posttraining. Exp II was conducted with 18 Ss and a larger dose of CYC. Results of Exp I show that strychnine sulfate attenuated an amnesia induced by 30 mg/kg CYC, and the results of Exp II show that even the robust amnesia induced by 75 mg/kg CYC could be attenuated by strychnine sulfate. Results concur with previous experiments that show that agents having little or no effect on the catecholamines can nonetheless attenuate amnesia induced by the protein synthesis inhibitors. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential recovery of function following caudate, hippocampal, and septal lesions in mice.

Tested female CF1 mice with bilateral caudate, hippocampal, or septal lesions for passive avoidance learning at 1-2, 7-8, or 28-29 days after surgery. Although each lesion induced a comparable learning impairment at 1-2 days after surgery, time-dependent recovery occurred only with caudate lesions. Each lesion also induced changes in sensitivity to dextroamphetamine and scopolamine at 1-2 days after surgery, and further time-dependent variations in drug sensitivity occurred only with caudate lesions. Results suggest that normal acquisition of passive avoidance behavior is mediated by a critical septal-hippocampal system and another, perhaps redundant, system involving the caudate. Time-dependent drug sensitivity changes following caudate lesions were consistent with a role of denervation supersensitivity in recovery of function. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental analysis of behavioral dysfunction in rats with septal lesions.

At 7 days of age, 48 male Long-Evans hooded rats received lesions of the septal nuclei or control operations. Ss then received 30 hrs of training on a DRL 20-sec schedule for 1 hr/day beginning at either 27 or 96 days of age. At 126 days of age, all Ss received 10 additional training sessions. After operant testing, all Ss received 10 additional training sessions. After operant testing, all Ss were tested on spontaneous alternation, spatial reversal, and passive avoidance. Results indicate that on a DRL 20-sec schedule Ss that received lesions of the septum neonatally and were tested at different ages performed in a similar manner. Approximately 50% of the Ss with lesions of the septal nuclei reached efficiency levels comparable with those of normal controls. When tested for retention, these efficient Ss still performed similarly to normal Ss. Ss with septal lesions were facilitated in the acquisition of a spatial habit, were deficient in spatial habit reversal, were less likely to demonstrate spontaneous alternation, and were deficient in passive avoidance. It is concluded that neonatal lesions of the septal nuclei produce permanent behavioral impairments on a diversity of measures and that, although juvenile animals with limbic system damage often manifest behaviors different from adult Ss, the difference is not evident during operant testing (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of overtraining on reversal and extradimensional shifts in schizophrenics.

In Exp. I, 50 schizophrenic Ss were trained under 1 of 3 discrimination learning conditions: reversal (R) shift, extradimensional (ED) shift, or control. 1/2 of the Ss in each shift condition received overtraining on the preshift discrimination. Performances of nonovertrained Ss on the R and ED shifts were very similar to performances of schizophrenic Ss tested by J. D. Nolan (see 42:11). Newman-Keuls analyses indicate that overtraining facilitated the R shift relative to the ED shift. The result was a significant overall effect due to shift type. In Exp. II, a replication of Exp. I, 60 undergraduates learned R shifts faster than ED shifts, but overtraining had no discernible effect. Results were compared with those reported by Nolan and were discussed in terms of a 2-stage attention model of discrimination learning. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)