Laminar distribution of neurofilament inclusions and swollen achromatic neurons in neurofilament inclusion disease (NID)

The laminar distribution of the neurofilament inclusions (NI) and swollen achromatic neurons (SN) was studied in gyri of the temporal cortex in four patients with neurofilament inclusion disease (NID). In 84% of gyri analysed, the density of the NI was maximal in the lower cortical laminae. The distribution of the SN was more variable than the NI. Density was maximal in the lower cortex in 46% of gyri, in the upper cortical laminae in 8% of gyri, and a bimodal distribution in 15% of gyri. In the remaining gyri, there was a more even distribution of SN with cortical depth. In 31% of gyri, the vertical density of the NI was positively correlated with that of the SN. The data suggest that cortical degeneration in the temporal lobe of NID initially affects neurons in the lower laminae. Subsequently, the pathology may spread to affect much of the cortical profile, the SN preceding the appearance of the NI.

Leader-member exchange in a Chinese context:antecedents, outcomes and mediating role of psychological empowerment

This study examines organizational antecedents of LMX and the mediating influence of empowerment on the relationships between LMX and the work outcomes of job satisfaction, task performance and psychological withdrawal behavior. Data were obtained from employees of a listed Chinese company in Guangdong Province, People's Republic of China. The results revealed that: (a) supervisor control of rewards and work unit climate were related to LMX and (b) empowerment fully mediated the relationship between LMX and the work outcomes as hypothesized.

Antecedents of leader-member exchange and explanation of its relationship with citizenship behavior

This study examined personal/interpersonal antecedents of leader-member exchange (LMX) and why and how LMX is related to the helping and voice dimensions of citizenship behavior. The results indicate that: (i) proactive personality and supervisor trust in employee were significant antecedents of LMX; (ii) the psychological empowerment dimension of autonomy partially mediated the LMX-helping relationship whereas the LMX-voice relationship was fully mediated the by autonomy and impact dimensions of psychological empowerment; and (iii) organization-based self-esteem more strongly moderated the LMX-helping relationship relative to the LMX-voice relationship.

Beyond personal Leader Member Exchange (LMX) quality:the effects of perceived LMX variability on employee reactions

A fundamental tenet of Leader–Member Exchange (LMX) theory is that leaders develop different quality relationships with their employees; however, little research has investigated the impact of LMX differentiation on employee reactions. The current research investigates whether perceptions of LMX variability (the extent to which LMX relationships are perceived to vary within a team) affects employee job satisfaction and wellbeing beyond the effects of personal LMX quality. As LMX variability runs counter to principles of equality and consistency, which are important for maintaining social harmony in groups, it is hypothesized that perceptions of LMX variability will have a negative effect on employee reactions, via its negative impact on perceived team relations. Two samples of employed individuals were used to investigate the hypothesized relationships. In both samples, an individual's perception of LMX variability in their team was negatively related to employee job satisfaction and wellbeing (above the effects of LMX), and this relationship was mediated by reports of relational team conflict.

A qualitative investigation into leader behavioural flexibility

Purpose – The current research aims to determine to what extent Australian managers are behaviourally flexible and to identify what factors are associated with the development of leader behavioural flexibility (LBF) and its contribution to positive organisational outcomes. Design/methodology/approach – Because of the exploratory nature of the questions to be addressed, a qualitative approach to data collection was selected. In particular, the grounded theory methodology was utilised due to its ability to aid with the theory building process. Semi-structured interviews based on the critical incident interview technique were used as the data source. Findings – The findings illustrate that the Australian managers who participated in this study exhibited significant degrees of LBF. The results also suggest that education level and group size may be antecedents to LBF. In addition, it appears that leader-member exchange may mediate the relationship between LBF and positive organisational outcomes, while social intelligence may moderate this relationship. Research limitations/implications – The current research makes several contributions in terms of theoretical development and reveals a richer insight into the underlying processes associated with the relationship between LBF and positive organisational outcomes. Practical implications – As the current research was conducted in the field with 20 practising organisational managers, the findings also highlight some important practical applications regarding LBF. Originality/value – Although previous studies have been able to establish a relationship between LBF and positive organisational outcomes, they have explained very little about the processes associated with this relationship. The present study attempted to uncover some of these processes.

Effective leadership in salient groups:revisiting leader-member exchange theory from the perspective of the social identity theory of leadership

Two studies compared leader-member exchange (LMX) theory and the social identity theory of leadership. Study 1 surveyed 439 employees of organizations in Wales, measuring work group salience, leader-member relations, and perceived leadership effectiveness. Study 2 surveyed 128 members of organizations in India, measuring identification not salience and also individualism/collectivism. Both studies provided good support for social identity predictions. Depersonalized leader-member relations were associated with greater leadership effectiveness among high-than low-salient groups (Study 1) and among high than low identifiers (Study 2). Personalized leadership effectiveness was less affected by salience (Study 1) and unaffected by identification (Study 2). Low-salience groups preferred personalized leadership more than did high-salience groups (Study 1). Low identifiers showed no preference but high identifiers preferred depersonalized leadership (Study 2). In Study 2, collectivists did not prefer depersonalized as opposed to personalized leadership, whereas individualists did, probably because collectivists focus more on the relational self.

The role of leader-member exchanges in mediating the relationship between locus of control and work reactions

The relationship between locus of control, the quality of exchanges between subordinates and leaders (LMX), and a variety of work-related reactions (intrinsic/extrinsic job satisfaction, work-related well-being, and organizational commitment) are examined. It was predicted that people with an internal locus of control develop better quality relations with their manager and this, in turn, results in more favourable work-related reactions. Results from two different samples (N=404, and N=51) supported this prediction, and also showed that LMX either fully, or partially, mediated the relationship between locus of control and all the work-related reactions.

Spatial patterns of the pathological changes in neuronal intermediate filament inclusion disease (NIFID):an α-internexin immunohistochemical study

Neuronal intermediate filament inclusion disease (NIFID) is characterized by α-internexin positive neuronal cytoplasmic inclusions (NCI), swollen achromatic neurons (SN), neuronal loss, and gliosis. This study tested: 1) whether the spatial patterns of the lesions was topographically organized in areas of the frontal and temporal lobe and 2) whether a spatial relationship exists between the NCI and SN. The NCI were distributed in regular clusters and in a quarter of these areas, the clusters were 400-800 μm in diameter approximating to the size of the cells of origin of the cortico-cortical pathways. Variations in the density of the NCI were positively correlated with the SN. Hence, cortical degeneration in NIFID appears to be topographically organized and may affect the cortico-cortical projections, the clusters of NCI and SN developing within the same vertical columns of cells. © 2007 Springer-Verlag.

Laminar degeneration of the frontal and temporal cortex in neuronal intermediate filament inclusion disease (NIFID): a study using a-internexin immunohistochemistry

Objective: To determine the laminar distribution of the pathological changes in the frontal and temporal lobe in neuronal intermediate filament inclusion disease (NIFID). Method: The distribution of the alpha-intenexin-positive neuronal cytoplasmic inclusions (NCI), surviving neurons, swollen achromatic neurons (SN) and glial cell nuclei was studied across the cortex in gyri of the frontal and temporal lobe in 10 cases of NIFID. Results: The distribution of the NCI was highly variable within different gyri, a peak in the upper cortex, a bimodal distribution with peaks of density in the upper and lower laminae, or no significant variation in density across the cortex. The surviving neurons were either bimodally distributed or exhibited no significant change in density across the cortex. The SN and glial cell nuclei were most abundant in the lower cortical laminae. In half of the gyri, variations in density of the NCI across the cortex were positively correlated with the SN. In some gyri, the surviving neurons were positively correlated with the SN and negatively correlated with the glial cell nuclei. In addition, the SN and glial cell nuclei were positively correlated in over half the gyri studied. Conclusion: The data suggest that frontal and temporal lobe degeneration in NIFID characterized by NCI, SN, neuronal loss and gliosis extends across the cortical laminae with considerable variation between cases and gyri. alpha-internexin-positive neurons in the upper laminae appear to be particularly vulnerable. The gliosis appears to be largely correlated with the appearance of SN and with neuronal loss and not related to the NCI.

Neuropathological changes in ten cases of neuronal intermediate filament inclusion disease (NIFID):A study using α-internexin immunohistochemistry and principal components analysis (PCA)

Ten cases of neuronal intermediate filament inclusion disease (NIFID) were studied quantitatively. The α-internexin positive neurofilament inclusions (NI) were most abundant in the motor cortex and CA sectors of the hippocampus. The densities of the NI and the swollen achromatic neurons (SN) were similar in laminae II/III and V/VI but glial cell density was greater in V/VI. The density of the NI was positively correlated with the SN and the glial cells. Principal components analysis (PCA) suggested that PC1 was associated with variation in neuronal loss in the frontal/temporal lobes and PC2 with neuronal loss in the frontal lobe and NI density in the parahippocampal gyrus. The data suggest: 1) frontal and temporal lobe degeneration in NIFID is associated with the widespread formation of NI and SN, 2) NI and SN affect cortical laminae II/III and V/VI, 3) the NI and SN affect closely related neuronal populations, and 4) variations in neuronal loss and in the density of NI were the most important sources of pathological heterogeneity. © Springer-Verlag 2005.

Topography of α-internexin-positive neuronal aggregates in 10 patients with neuronal intermediate filament inclusion disease

Abnormal neuronal intermediate filament (IF) inclusions immunopositive for the type IV IF α-internexin have been identified as the pathological hallmark of neuronal intermediate filament inclusion disease (NIFID). We studied the topography of these inclusions in the frontal and temporal lobe in 68 areas from 10 cases of NIFID. In the cerebral cortex, CA sectors of the hippocampus, and dentate gyrus granule cell layer, the inclusions were distributed mainly in regularly distributed clusters, 50-800 μm in diameter. In seven cortical areas, there was a more complex pattern in which the clusters of inclusions were aggregated into larger superclusters. In 11 cortical areas, the size of the clusters approximated to those of the cells of origin of the cortico-cortical pathways but in the majority of the remaining areas, cluster size was smaller than 400 μm. The topography of the lesions suggests that there is degeneration of the cortico-cortical projections in NIFID with the formation of α-internexin-positive aggregates within vertical columns of cells. Initially, only a subset of cells within a vertical column develops inclusions but as the disease progresses, the whole of the column becomes affected. The corticostriate projection appears to have little effect on the cortical topography of the inclusions. © 2006 EFNS.

Spatial patterns of the pathological changes in the temporal lobe of patients with neuronal intermediate filament inclusion disease

Neuronal intermediate filament inclusion disease (NIFID) is a new neurodegenerative disease characterized histologically by the presence of neuronal cytoplasmic inclusions (NI) immunopositive for intermediate filament proteins, neuronal loss, swollen achromatic neurons (SN), and gliosis. We studied the spatial patterns of these pathological changes parallel to the pia mater in gyri of the temporal lobe in four cases of NIFID. Both the NI and SN occurred in clusters that were regularly distributed parallel to the pia mater, the cluster sizes of the SN being significantly greater than those of the NI. In a significant proportion of areas studied, there was a spatial correlation between the clusters of NI and those of the SN and with the density of the surviving neurons. In addition, the clusters of surviving neurons were negatively correlated (out of phase) with the clusters of glial cell nuclei. The pattern of clustering of these histological features suggests that there is degeneration of the cortico-cortical projections in NIFID leading to the formation of NI and SN within the same vertical columns of cells. The glial cell reaction may be a response to the loss of neurons rather than to the appearance of the NI or SN.