Evidence for the substantia nigra pars compacta as an essential component of a memory system independent of the hippocampal memory system

The aim of the present study was to test if the nigrostriatal pathway is an essential component for a water maze cued task learning and if it works independently of the hippocampal memory system. This hypothesis was tested using an animal model of Parkinson's disease in which male Wistar rats were lesioned in the substantia nigra pars compacta (SNc) by the intranigral infusion of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), thus causing a partial depletion of striatal dopamine. SNc-lesioned and sham-operated animals were implanted bilaterally with guide cannulae above the dorsal hippocampus in order to be tested after the administration of 0.4 microl 2% lidocaine or saline into this structure. The animals were tested in a spatial or in a cued version of the water maze, memory tasks previously reported to model hippocampal-dependent spatial/relational and striatal-dependent S-R learning, respectively. Hippocampal inactivation, but not SNc lesion, impaired learning and memory in the spatial version of the water maze. An opposite situation was observed with the cued version. No significant interaction was observed between the SNc lesion and hippocampal inactivation conditions affecting scores in the spatial or in the cued version of the water maze. These results suggest that the nigrostriatal pathway is an essential part of the memory system that processes S-R learning and that it works independently of the hippocampal memory system that processes spatial/relational memories.     

Do Birds of a Feather Flock Together? An Examination of Calling,Congruence, Job Design and Personality as Predictors of Job Satisfaction and Tenure

This study explored whether congruence, calling, job characteristics or personality were better predictors of job satisfaction and tenure. The sample consisted of 1968 employees across four different job roles: sales engineers (N=309), graphic designers (N=383), teachers (N=481) and clergy (N=795). Data was collected as part of a selection and development centre battery. Results found evidence of calling, with clergy reporting significantly higher levels of work satisfaction and tenure, despite the absence of some personality predictors (i.e. conscientiousness) and job characteristics (task identity, feedback). In general personality [particularly conscientiousness (+) and neuroticism (-)] along with job characteristics (variety and autonomy) were the most likely predictors of satisfaction across the different roles. No evidence could be found that congruence predicted work satisfaction or tenure. Results have implications for renewed interest in the role of calling according to its original definition and question the role of congruence in determining best fit especially in the context of vocational assessments.     

Attitudes Toward Affirmative Action as a Function of the Strength of Ethnic Identity Among Latino College Students1

The present study examined support for affirmative action among Latino college students as a function of ethnic identity. We found that, overall, Latino students generally endorsed affirmative action and did not feel undermined by it. Of primary interest to us was variation in support for affirmative action as a function of ethnic identity. The more the Latino students identified with their ethnic group, the more they endorsed affirmative action.     

The role of nucleus accumbens and dorsolateral striatal D2 receptors in active avoidance conditioning

The role of dopamine (DA) in rewarding motivated actions is well established but its role in learning how to avoid aversive events is still controversial. Here we tested the role of D2-like DA receptors in the nucleus accumbens (NAc) and the dorsolateral striatum (DLS) of rats in the learning and performance of conditioned avoidance responses (CAR). Adult male Wistar rats received systemic, intra-NAc or intra-DLS (pre- or post-training) administration of a D2-like receptor agonist (quinpirole) or antagonist ((−)sulpiride) and were given two sessions in the two-way active avoidance task. The main effects observed were: (i) sulpiride and lower (likely pre-synaptic) doses of quinpirole decreased the number of CARs and increased the number of escape failures; (ii) higher doses of quinpirole (likely post-synaptic) increased inter-trial crossings and failures; (iii) pre-training administration of sulpiride decreased the number of CARs in both training and test sessions when infused into the NAc, but this effect was observed only in the test session when it was infused into the DLS; (iv) post-training administration of sulpiride decreased CARs in the test session when infused into the NAc but not DLS. These findings suggest that activation of D2 receptors in the NAc is critical for fast adaptation to responding to unconditioned and conditioned aversive stimuli while activation of these receptors in the DLS is needed for a slower learning of how to respond to the same stimuli based on previous experiences.     

Take a Job,Any Job: Exploring the Importance of Matched Interests to Career Paths and Work Satisfaction

Employment counselors often face the conundrum of whether to advise people to take a job or to hold out for something that better matches their interests. This study investigated whether matched interests in an initial job predicted the subsequent career journey of 336 sales engineers and whether this made a difference to longer term work satisfaction and tenure. Results showed that although the first job significantly influenced people's future career journey, personality and job characteristics were likely to be more influential than matched interests in predicting work satisfaction. Thus, people may be better off taking well‐designed jobs than holding out for matched interests.     

Developmental trends in the interaction between auditory and linguistic processing

The developmental course of multidimensional speech processing was examined in 80 children between 3 and 6 years of age and in 60 adults between 20 and 86 years of age. Processing interactions were assessed with a speeded classification task (Garner, 1974a), which required the subjects to attend selectively to the voice dimension while ignoring the linguistic dimension, and vice versa. The children and adults exhibited both similarities and differences in the patterns of processing dependencies. For all ages, performance for each dimension was slower in the presence of variation in the irrelevant dimension; irrelevant variation in the voice dimension disrupted performance more than irrelevant variation in the linguistic dimension. Trends in the degree of interference, on the other hand, showed significant differences between dimensions as a function of age. Whereas the degree of interference for the voice-dimension-relevant did not show significant age-related change, the degree of interference for the word-dimension-relevant declined significantly with age in a linear as well as a quadratic manner. A major age-related change in the relation between dimensions was that word processing, relative to voice-gender processing, required significantly more time in the children than in the adults. Overall, the developmental course characterizing multidimensional speech processing evidenced more-pronounced change when the linguistic dimension, rather than the voice dimension, was relevant.     

Personality Homogeneity in Organizations and Occupations: Considering Similarity Sources

Purpose

The purpose of this study was to investigate organizational and occupational homogeneity, compare homogeneity at different levels of composition, and uncover a mechanism for homogeneity.

Design/Methodology/Approach

Data were obtained from an archival data base of current employees (N = 23,933) in 40 organizations, 19 major job groupings, 42 minor job groupings, and 115 detailed job titles.

Findings

Support for homogeneity within organizations and occupations was found, regardless of the granularity with which occupation were defined. Homogeneity estimates were smaller than prior estimates in the literature based on smaller, less diverse samples. Occupational homogeneity was significantly greater than homogeneity at the organizational level for neuroticism and extraversion. As a potential mechanism, we demonstrated that occupational interest could predict personality at the occupational level.

Implications

Investigating homogeneity effects with a large, representative sample and simultaneously considering occupation and organization helps to advance our theoretical understanding of the Attraction–Selection–Attrition process. This study provides evidence of relative homogeneity effects and mechanisms. Such knowledge could help inform the selection, training, and socialization tactics employed by practitioners.

Originality/Value

Little is currently known about how within-occupation homogeneity in personality relates to within-organization homogeneity, or the influence of vocational interests on such homogeneity. We provide a methodological update to decompose and compare organizational and occupational influence on personality homogeneity. We also assess homogeneity at three levels of occupational granularity, and delineate a mechanism for personality to become homogeneous at the occupation level.

     

Pre-training to find a hidden platform in the Morris water maze can compensate for a deficit to find a cued platform in a rat model of Parkinson's disease

The bilateral intranigral infusion of 1 micromol 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in adult male Wistar rats caused a specific and partial loss of substantia nigra pars compacta (SNc) dopamine neurons, a partial depletion of striatal dopamine, and a deficit to learn the intra-maze cued version of the Morris water maze. Pre-training the SNc rats in the spatial version of the water maze or simply maintaining the animals on the water maze platform reversed this deficit. This improvement was even observed when the order of the extra-maze cues presented to the rats during pre-training of the spatial version was changed during training of the intra-maze cued version. However, this deficit was not reversed either by maintaining the animals on the platform if the spatial cues were surrounded and covered with a curtain or by swimming sessions in the maze without the escape platform and the curtain. These findings suggest that none of the following elements alone, learned during the spatial task pre-training, could help SNc rats learn the intra-maze cued task: improvement of swimming skills or knowledge of the existence of the escape platform; distance between the platform and the border of the pool; location of a particular extra-maze cue; relations among extra-maze cues. However, the simultaneous presence of the escape platform and extra-maze cues (irrespective of their relational configuration) during the pre-training sessions proved to be necessary for this improving effect to occur.