Analysis of the elements of attention: A neuropsychological approach

A model for conceptualizing the components or elements of attention is presented. The model substitutes for the diffuse and global concept of attention a group of four processes and links them to a putative system of cerebral structures. Data in support of the model are presented; they are derived from neuropsychological test scores obtained from two samples, the first consisting of 203 adult neuropsychiatric patients and normal control subjects, and the second, an epidemiologically-based sample of 435 elementary school children. Principal components analyses of test scores from these two populations yielded similar results: a set of independent elements of attention that are assayed by different tests. This work presents a heuristic for clinical research in which the measurement of attention is essential.     

Does Traumatic Brain Injury Attenuate the Exposure Therapy Process?

Research indicates that exposure therapy is efficacious for combat-related posttraumatic stress disorder (PTSD) comorbid with traumatic brain injury (TBI) as is shown by reduced PTSD treatment outcome scores. What is unknown, however, is whether the process of fear extinction is attenuated in veterans with TBI history. Increased PTSD symptomatology and possible cognitive deficits associated with TBI sequelae may indicate additional or longer exposure sessions to achieve habituation and extinction comparable to individuals without TBI history. As such, a more extensive course of treatment may be necessary to achieve comparable PTSD treatment outcome scores for individuals with TBI history. Using a sample of veterans with combat-related PTSD, some of whom were comorbid for TBI, this study compared process variables considered relevant to successful treatment outcome in exposure therapy. Individuals with and without TBI demonstrated similar rates of fear activation, length and number of exposure sessions, within-session habituation, between-session habituation, and extinction rate; results remained consistent when controlling for differential PTSD symptomatology. Furthermore, results indicated that self-perception of executive dysfunction did not impact the exposure process. Results suggest that individuals with PTSD and TBI history engage successfully and no differently in the exposure therapy process as compared to individuals with PTSD alone. Findings further support exposure therapy as a first-line treatment for combat-related PTSD regardless of TBI history.     

Repetition priming reveals hemispheric differences in compound word processing

The left (LH) and right (RH) hemispheres are thought to implement different mechanisms for visual word recognition; the LH’s parallel encoding strategy is more efficient than the RH’s serial, letter-by-letter analysis. Here we examine differences in hemispheric language processing strategy by investigating repetition priming of compound words (e.g. buttercup) and their constituents (e.g. butter, cup). Eighty-eight right-handed participants (29 M, 59 F) completed a lexical decision experiment in which centrally-presented compounds primed related (whole compound, first constituent, second constituent) and unrelated targets presented laterally to the left or right visual field; participants made button-press word/nonword decisions. Consistent with the LH parallel/RH serial distinction, repetition priming prompted an RH advantage for first constituents, whereas the LH performed equally efficiently in response to both first and second constituents. These data thus highlight differences in the hemispheres’ language processing strategies, offering new evidence supporting a relative parallel/serial distinction in LH/RH visual word recognition.     

Counter‐intuitive moral judgement following traumatic brain injury

Several neurological patient populations, including traumatic brain injury (TBI), appear to produce an abnormally ‘utilitarian’ pattern of judgements to moral dilemmas; they tend to make judgements that maximize the welfare of the majority, rather than deontological judgements based on the following of moral rules (e.g., do not harm others). However, this patient research has always used extreme dilemmas with highly valued moral rules (e.g., do not kill). Data from healthy participants, however, suggest that when a wider range of dilemmas are employed, involving less valued moral rules (e.g., do not lie), moral judgements demonstrate sensitivity to the psychological intuitiveness of the judgements, rather than their deontological or utilitarian content (Kahane et al., Social Cognitive and Affective Neuroscience, 7, 2011, 393). We sought the moral judgements of 30 TBI participants and 30 controls on moral dilemmas where content (utilitarian/deontological) and intuition (intuitive/counter‐intuitive) were measured concurrently. Overall TBI participants made utilitarian judgements in equal proportions to controls; disproportionately favouring utilitarian judgements only when they were counter‐intuitive, and deontological judgements only when they were counter‐intuitive. These results speak against the view that TBI causes a specific utilitarian bias, suggesting instead that moral intuition is broadly disrupted following TBI.     

论神经哲学的兴起

人类心身问题的研究一直是科学界关注的热点。近年来,国外学者将神经科学与哲学研究统一起来,集合两门学科的研究方法、综合双方的研究成果,以此来共同推进人类心身问题的研究,因此诞生了一门介于神经科学和哲学之间的独立学科,它有着学科交叉的研究领域和特殊的跨学科研究方法,这门学科就是神经哲学。     

Synapses,Schizophrenia, and Civilization: What Made Homo Sapient?

Progress in technology has allowed dynamic research on the development of the human brain that has revolutionized concepts. Particularly, the notions of plasticity, neuronal selection, and the effects of afferent stimuli have entered into thinking about brain development. Here I focus on development from the age of four years to early adulthood, during which a 30 percent reduction in some brain synapses occurs that is out of proportion to changes in neuronal numbers. This corresponds temporally with changes in normal child behavior from the loose‐associative, almost schizoid, thinking and art of the four‐year‐old to the more trained, or disciplined, or acculturated—and restrained—personality of the young adult. I propose that the synaptic changes can best be thought of as a winnowing process likely subject to environmental influences. Acquisition of language and the ability to link linguistic cognition to the plastic development of the brain provide a potentially powerful means of explaining the evolutionally explosive development of human cognition and culture. Schizophrenia, a disease that can be envisioned as representing a derangement of synaptic maturation, may provide an entry into the search for genes controlling the processes mediating the unprecedented development of Homo sapiens over the past 40,000 to 70,000 years. The recently completed mapping of the genome of the chimpanzee provides a new frame of reference that may speed the search.