Unpicking the semantic impairment in Alzheimer's disease: qualitative changes with disease severity

Despite a vast literature examining semantic impairment in Alzheimer's disease (AD), consensus regarding the nature of the deficit remains elusive. We re-considered this issue in the context of a framework that assumes semantic cognition can break down in two ways: (1) core semantic representations can degrade or (2) cognitive control mechanisms can become impaired. We hypothesised and confirmed that the nature of semantic impairment in AD changes with disease severity. Patients at mild or severe stages of the disorder exhibited impairment across various semantic tasks but the nature of those deficits differed qualitatively for the two groups. Commensurate with early dysfunction of the cognitive control, temporoparietal-frontal-cingulate network, characteristics of deregulated semantic cognition were exhibited by the mild AD cases. In contrast, the severe AD group reproduced features of additional degradation of core semantic representations. These results suggest that spread of pathology into lateral anterior temporal lobes in later stage AD produces degradation of semantic representations, exacerbating the already deregulated system. Moreover, the dual nature of severe patients' impairment was highlighted by disproportionately poor performance on tasks placing high demand on both conceptual knowledge and control processes--e.g., category fluency.     

The left superior longitudinal fasciculus within the primary sensory area of inferior parietal lobe plays a role in dysgraphia of kana omission within sentences

Functional neurological changes after surgery combined with diffusion tensor imaging (DTI) tractography can directly provide evidence of anatomical localization of brain function. Using these techniques, a patient with dysgraphia before surgery was analyzed at our hospital in 2011. The patient showed omission of kana within sentences before surgery, which improved after surgery. The brain tumor was relatively small and was located within the primary sensory area (S1) of the inferior parietal lobe (IPL). DTI tractography before surgery revealed compression of the branch of the superior longitudinal fasciculus (SLF) by the brain tumor. These results suggest that the left SLF within the S1 of IPL plays a role in the development of dysgraphia of kana omission within sentences.     

Cognitive structure of writing disorders in Russian: what would Luria say?

Acquired disorders of writing in the Russian language have been reported for more than a century. The study of these disorders reflects the history of Russian neuropsychology and is dominated by the syndrome approach most notably by the writings of Luria. Indeed, our understanding of acquired dysgraphia in Russian speakers is conceptualized according to the classical approach in Modern Russia. In this review, we describe the classical approach and compare it to the cognitive neuropsychological models of writing disorders that are developed to explain dysgraphia in English and in other Western European languages. We argue that the basic theoretical assumptions of the two approaches - cognitive and classical or syndrome approach - share similarities. It is therefore proposed that identification of acquired cases of dysgraphia in Russian could potentially benefit from taking the cognitive neuropsychological perspective. We also conclude that adopting elements of the syndrome approach would substantially enrich the understanding of acquired dysgraphia since these offer an insight into processes not described in the cognitive neuropsychological approach.     

Does power magnify the expression of dispositions?

Conventional wisdom holds that power holders act more in line with their dispositions than do people who lack power. Drawing on principles of construct accessibility, we propose that this is the case only when no alternative constructs are activated. In three experiments, we assessed participants' chronic dispositions and subsequently manipulated participants' degree of power. Participants then either were or were not primed with alternative (i.e., inaccessible or counterdispositional) constructs. When no alternatives were activated, the responses of power holders--perceptions of other people (Experiment 1), preferences for charitable donations (Experiment 2), and strategies in an economic game (Experiment 3)--were more in line with their chronically accessible constructs than were the responses of low-power participants. However, when alternatives had been activated, power holders' responses were no longer more congruent with their dispositions than were the responses of low-power participants. We propose a single mechanism according to which power increases reliance on accessible constructs--that is, constructs that easily come to mind-regardless of whether these constructs are chronically or temporarily accessible.     

Who are you looking at? The influence of face gender on visual attention and memory for own- and other-race faces

Previous research suggests that the own-race bias (ORB) in memory for faces is a result of other-race faces receiving less visual attention at encoding. As women typically display an own-gender bias in memory for faces and men do not, we investigated whether face gender and sex of viewer influenced visual attention and memory for own- and other-race faces, and if preferential viewing of own-race faces contributed to the ORB in memory. Participants viewed pairs of female or male own- and other-race faces while their viewing time was recorded. Afterwards, they completed a surprise memory test. We found that (1) other-race males received the initial focus of attention, (2) own-race faces were viewed longer than other-race faces over time, although the difference was larger for female faces, and (3) even though longer viewing time increased the probability of remembering a face, it did not explain the magnified ORB in memory for female faces. Importantly, these findings highlight that face gender moderates attentional responses to and memory for own- and other-race faces.     

Credible suggestions affect false autobiographical beliefs

False memory implantation studies are characterised by suggestions indicating that specific unremembered events occurred, attributing suggested events to a knowledgeable source (e.g., parents), and including true events that provide evidence that this source was consulted. These characteristics create a particular retrieval context that influences how individuals come to believe that false events occurred. Two studies used a variant of implantation methods to vary the proportion of events attributed to parents and the presence of true events within the suggestion. In Study 1 participants received six false events, and were told that all or some events came from parents. Participants told that all of the events came from parents formed more and stronger false beliefs. In Study 2 participants also received two true events, and a third group was told that half of the events came from their parents. Participants given the specific ratio ("half") endorsed more false beliefs, and beliefs between the other groups no longer differed. Across both studies participants told that some events came from parents reported stronger memory phenomenology. The effect of suggestions on false beliefs in implantation studies depends partly on the credibility of suggestions derived from providing information about the source of suggested events.     

A longitudinal study of processes predicting the specificity of autobiographical memory in the adolescent offspring of depressed parents

Deficits in specific autobiographical memory retrieval are closely associated with depression. The ability to retrieve specific autobiographical memories develops throughout childhood and adolescence and is associated with adolescent depression within and across time. Studying young samples before they first experience depression provides an approach for testing processes that underlie reduced autobiographical memory specificity. This study is the first to examine the longitudinal association of rumination and executive function with autobiographical memory specificity in a sample of adolescents at elevated risk for future depression. A total of 259 adolescents (aged between 10 and 18 years) completed the Autobiographical Memory Test at baseline and 1-year follow-up. Measures of rumination, executive function, and depressive symptoms were obtained at baseline. The interaction between rumination and executive function predicted autobiographical memory specificity over time. Whereas rumination in the context of low executive function predicted reduced specificity, this was not the case in the context of high executive function. The interaction between rumination and executive function was independent of the effects of age, gender, IQ, baseline levels of memory specificity, and depressive symptoms.     

Accurate, inaccurate and omitted details in collective emotional memories: The case of Itzhak Rabin's assassination

Collective memory of the assassination of the former Israeli Prime Minister, Itzhak Rabin, was originally examined by asking 61 Israeli students, about two weeks after the assassination (T1) and about 11 months later (T2) to fill out an open-ended questionnaire about the assassination. About 13 years later (T3) a new sample of 80 students also filled out the memory questionnaire. In T2 and T3 the participants also self-assessed various emotional and cognitive variables about their memories. All answers were segmented and categorised into accurate and inaccurate memories. Data analyses showed that the amounts of accurate memories decreased from T1 to T2 by 18 per cent, and from T2 to T3 by an additional 16 per cent, and were positively correlated in T2 with national importance and emotional reaction, and in T3 with self-assessed ability to remember events and amounts of visual representations. Content analysis of the most frequently memorised accurate, inaccurate and omitted memories showed that they displayed differential qualitative characteristics and that the most prevalent accurate narrative has varied over time. It appears that the collective memories of Rabin's assassination showed episodic features similar to those shown by eyewitnesses exposed to emotion-arousing events only once. The data suggest a distinction between episodic "collective memories" and semantic "collective knowledge".     

The role of warning behaviors in threat assessment: an exploration and suggested typology

The concept of warning behaviors offers an additional perspective in threat assessment. Warning behaviors are acts which constitute evidence of increasing or accelerating risk. They are acute, dynamic, and particularly toxic changes in patterns of behavior which may aid in structuring a professional's judgment that an individual of concern now poses a threat - whether the actual target has been identified or not. They require an operational response. A typology of eight warning behaviors for assessing the threat of intended violence is proposed: pathway, fixation, identification, novel aggression, energy burst, leakage, directly communicated threat, and last resort warning behaviors. Previous research on risk factors associated with such warning behaviors is reviewed, and examples of each warning behavior from various intended violence cases are presented, including public figure assassination, adolescent and adult mass murder, corporate celebrity stalking, and both domestic and foreign acts of terrorism. Practical applications and future research into warning behaviors are suggested.