The differential role of premotor frontal cortex and basal ganglia in motor sequence learning: evidence from focal basal ganglia lesions

There has been a growing interest in the differential role of various neural structures in implicit learning processes. The goal of our study was to clarify how focal lesions restricted to the basal ganglia interfere with different aspects of implicit visuo-motor sequence learning. A version of the Serial Reaction Time Task (SRTT) of Nissen and Bullemer using a 12-trial sequence was administered. A total of 20 subjects with focal basal ganglia lesions caused by ischemic or hemorrhagic infarction and 20 matched control subjects participated in this study. The results indicate that subjects with focal basal ganglia lesions showed unimpaired implicit learning of a 12-item motor sequence. Subjects with basal ganglia lesions, however, had more difficulties improving their general proficiency with the reaction-time task independent of sequence-specific learning. We observed a tendency toward smaller regional volumes in the cerebellum and left pre-supplementary motor area (pre-SMA) of subjects with basal ganglia lesions. Smaller cerebellar and pre-SMA volumes were related to lower implicit learning performance in the lesion group. The size of lesions in the basal ganglia was not related to sequence-specific implicit learning but had a significant influence on subjects' general proficiency for execution of the reaction-time task. We propose that implicit learning is achieved by a distributed network of cortical and subcortical structures. The basal ganglia seem to be responsible for adjusting to the general requirements of a task rather than for learning specific associations between stimuli that might be accomplished by premotor frontal areas and the cerebellum instead.     

Laminar-dependent dendritic spine alterations in the motor cortex of adult rats following callosal transection and forced forelimb use

Previously, the authors found that partial denervation of the motor cortex in adult animals can enhance this region's neuronal growth response to relevant behavioral change. Rats with partial corpus callosum transections that were forced to rely on one forelimb for 18 days had increased dendritic arborization of layer V pyramidal neurons in the opposite motor cortex compared to controls. This was not found as a result of denervation alone or of forced forelimb use alone. However, it seemed possible that each independent manipulation (i.e., forced forelimb use alone and callosal transections alone) resulted in neural structural alterations that were simply not revealed in measurements of dendritic branch number and/or not inclusive of layer V dendrites. This possibility was assessed in the current study with a reexamination of the Golgi-Cox impregnated tissue generated in the previous study. Tissue was quantified from rats that received either partial transections of the rostral two-thirds of the corpus callosum (CCX) or sham operations (Sham) followed either by 18 days of forced use of one forelimb (Use) or unrestricted use of both forelimbs (Cont). Measurements of apical and basilar dendrites from pyramidal neurons of layer II/III and layer V were performed to detect spine addition resulting from either increased spine density or the addition of dendritic material. As hypothesized, significant spine addition was found following forced forelimb use alone (Sham+Use) and callosal transections alone (CCX+Cont). However, forced use primarily increased spines on layer II/III pyramidal neurons, whereas callosal transections primarily increased dendritic spines on layer V pyramidal neurons in comparison to Sham+Cont. A much more robust increase in layer V dendritic spines was found in animals with the combination of forced forelimb use and denervation (CCX+Use). In contrast to the effects of forced use alone, however, CCX+Use rats failed to show major net increases in spines on layer II/III neurons. These results indicate that while callosal denervation may greatly enhance the neuronal growth and synaptogenic response to behavioral change in layer V, it may also limit spine addition associated with forced forelimb use in layer II/III of the motor cortex.     

Interviews of female patients with borderline personality disorder who dropped out of group psychotherapy

Premature termination from group psychotherapy continues to be a serious problem in the treatment of patients with borderline personality disorder (BPD). Qualitative research is regarded as an important means to shed light upon the complex dynamics leading to dropout. We conducted an interview study with patients having a diagnosis of BPD (n = 8) who dropped out from long-term group psychotherapy as a continuation therapy following intensive day treatment. The group therapists for these patients were interviewed as well (n = 12). The findings suggest the operation of many processes that contribute to dropout. Most significant appeared to be experiences of separation and loss of the day hospital that were not worked through and a failure of the group to regulate and contain the patients' affects. To integrate patients at risk of premature termination it seems necessary to pay attention to the strong negative emotions that they experience in the group. A higher treatment intensity than weekly group sessions may help to promote more beneficial group processes.     

An overview of the literature on sexual harassment: Perpetrator,theory, and treatment issues

Sexual harassment has been recognized as a serious problem in the literature over the past 30 years. In this paper, we review the existing research surrounding the phenomenon of sexual harassment, paying particular attention to factors of relevance for understanding perpetrators of sexual harassment. We also provide an overview of the perplexing nature of sexual harassment and the various concerns that have surrounded the topic leading to its recognition. The different theoretical perspectives and models of sexual harassment (sociocultural, organizational, sex-role spillover, natural/biological, socio-cognitive, and four-factor) are also considered and reviewed. Finally, lack of empirical evidence and focus on assessment and treatment for harassers is recognized in this paper, and several suggestions are made for future research and treatment avenues relating to the sexual harasser.     

When stereotype‐based expectancies impair performance: the effect of prejudice,race, and target quality on judgments and perceiver performance

High‐ and low‐prejudiced participants were presented with a lecture segment in which the race of the professor (White or Black) and lecture quality (high or low) were manipulated. Consistent with predictions, low‐prejudiced participants were more extreme in their evaluations (more negative) and performed more poorly on test items when presented with an expectancy‐violating low‐quality Black lecturer. High‐prejudiced participants were more extreme in their evaluations (more positive) and performed more poorly when presented with an expectancy‐violating high‐quality Black lecturer. Copyright © 1999 John Wiley & Sons, Ltd.     

THE REDUCTION OF SELF INJURY IN TWO ADOLESCENTS WITH PROFOUND RETARDATION BY THE ESTABLISHMENT OF A SUPPORTED ROUTINE

Two experiments applied a conceptualization of competence to the treatment of self injury in two adolescents with profound retardation. In Experiment 1, a multiple baseline design across two activity periods was used to assess the effects of reinforcing completion of a five-step packaging routine on repetitious facial hitting in one participant. The rate of facial hits decreased when teachers reduced the latency between a pause by the participant and a prompt from the teacher to continue, pauses having been observed to be followed often by sequence errors, and sequence errors by facial hitting. In Experiment 2, a reversal design was used to compare the effects on head hitting and hand biting by substituting a premeal and dining routine in a second participant. The new routine replaced a largely instructional routine that required discriminations, receptive language, and motor performances not likely to emerge in the participant's repertoire. Discontinuation of the instructional routine reduced self injury; institution of the new routine permitted the development of a highly independent series of performances without reoccurrence of self injury. The combined results of the two experiments point to the potentially evocative nature of common teaching approaches and techniques, and the habilitative effects of designing performance expectations with greater prognosis for acquisition.     

Moral Imperatives for the Millennium: The Historical Construction of Race and Its Implications for Childhood and Schooling in the Twentieth Century

This essay argues strongly that racism in the United States hurts thefuture of all children. To eradicate this pernicious mindset inits institutional forms requires that we understand that race,as an idea that shapes social organization in this country,is a unique historical product dating from the colonial periodof the southern colonies of mainland British North America.Further, the mythology about American history, as it is taughtin school, excuses and legitimates continued inequality,oppression, and racism today. This essay traces the historyof class oppression from the 17th century, when the institutionof slavery was invented as a means of securing the unpaidchattel bonded labor of Anglo-Europeans, to the emergenceof unfree labor as a form of racial oppression, and subsequently the institutionalization of racial slavery inthe 18th century. Racial slavery, which elevated whitesupremacy and privilege, was still not synonymous with themodern form of pseudo-scientific racism that emerged as adefense of slavery in the antebellum period and its aftermathin the Civil War and Reconstruction. Racism and the legacyof white privilege is still used as a means of social controlto mask class relations and to thereby control and diminishcollective social action that potentially would occurin the absence of the color line. Knowledge of race as anhistorical construct created by human beings in particularcircumstances raises the possibility that race, racism, and its effects can also be changed by human beings acting in opposition to the conditions that artificially separate us.     

The motivating impact of informing women smokers of a link between smoking and cervical cancer: the role of coherence.

This research assessed the role of having a coherent explanation of the link between smoking and cervical cancer in motivating women to stop smoking. In the 1st study, women were given a leaflet with either a detailed or a minimal explanation of the link or no leaflet. The leaflets were similarly effective at providing a coherent explanation. In a cross-sectional analysis, having a coherent explanation moderated the relationship between perceived vulnerability and intention: Higher perceived vulnerability to cervical cancer was associated with greater intention to quit smoking only amongst women with a more coherent explanation of the link between smoking and cervical cancer. This finding was replicated in a 2nd study. These results are consistent with H. Leventhal et al.'s (1997) self-regulatory model, which suggests that motivation to change behavior depends not only on perceiving a threat but also on having a coherent model linking the behavior with the threat.