Brain dynamics,psychophysiological uncertainty and behavioral learning

The present paper takes a first step toward the integration of recent findings on brain dynamics and learning into established fields of psychophysiological science. Leading-edge studies of brain dynamics have shown that the brain manifests an inherent variability and that, when new stimuli (i.e., “problems”) are presented to the organism, brain chaos increases.     

Neurobehavioral deficits,adolescent traumatic brain injury,and transition to college

Outcome following traumatic brain injury (TBI) has been frequently evaluated for adults, although there has been minimal research on adolescents with TBI. It has been argued that TBI sequelae may be more difficult for adolescents to adjust to given developmental changes in physical (puberty), interpersonal (self-concept), and environmental domains (transition to college). In addition, it is commonly acknowledged that moderator variables such as psychiatric history, family functioning, substance use, and sexuality impact functional outcome following TBI, although it is often difficult to objectively evaluate these variables. The current study examined relationships among TBI-related deficits, moderator variables, and academic outcomes for six adolescents transitioning to college. The findings suggest that it may not be appropriate to predict functional outcome based solely on objective neuropsychological results. However, moderator variables appear to have a more direct relationship with outcome, depending on the moderator variable and the individual.     

Clinical neuropsychology and brain injury rehabilitation in Israel: A twenty-year perspective

The development of the field of neuropsychology in Israel is primarily the result of the development of rehabilitation services for traumatic brain-injured patients. The responsibility to care for and help disabled veterans has always been an important motivation for the establishment of rehabilitation services. Israel is probably one of the first countries in the world to develop community-based services specifically designed to address the needs of young patients with severe traumatic brain injury. The fairly extensive therapeutic and community services available today for both military and civilian brain-injured persons in Israel are the result of initiatives and funding by the Israel Ministry of Defense's Department of Rehabilitation. There are two principles that characterize most of the programs in Israel: (1) multidimensional remedial intervention and (2) life-time commitment to provide support. The accessibility of patients in a small country enables professionals to conduct follow-up studies in order to evaluate the long-term effects of brain injury. Current developments in neuropsychology are in three directions. First, formal training programs in neuropsychology are being set up. Second, the involvement of neuropsychologists is being extended beyond the treatment of young patients suffering from traumatic brain injury to include the treatment of different brain pathologies in children and the elderly. Third, sophisticated neuroimaging techniques are being applied to studies in cognitive neuropsychology.     

Stress,coping resources,and injury risk

Over the last two and a half decades, researchers have tried to determine if psychological variables predispose or buffer athletes from injury. They have found that sport participants who experience many recent stressors, and who do not have the resources and skills to cope with the stress, seem most at risk for injury. This article reviews that research as well as efforts to identify mechanisms that might explain why the stress-injury relationship occurs and interventions that will hopefully reduce the injury risk. Because the multicomponent stress-injury model of Andersen and Williams (1988) helped provide the impetus and theoretical base for much of that research, it serves as the foundation for organizing and summarizing the findings. Although the research has focused largely on sport injuries, the findings have relevance for understanding and potentially preventing many accidents and injuries that occur outside the realm of sport participation.     

Prevalence of traumatic brain injury in an inpatient psychiatric population

This study investigated the prevalence of traumatic brain injury (TBI) in an inpatient psychiatric population. We hypothesized increased prevalence of TBI relative to the general population due to a variety of risk factors observed in psychiatric patients. One hundred (mean age = 34) psychiatric inpatients completed the revised Head Injury Questionnaire. Chart review of 17 subjects reporting injuries established whether injuries were documented in medical records. Sixty-eight percent of this psychiatric population reported one or more injuries in which they were unconscious or dazed. This number is higher than the prevalence in the general population. Injuries were generally of mild to moderate severity; multiple injuries were common. Chart review of 17 subjects reporting TBI indicated that histories of TBI had not been noted in the medical record. Finally, 63% of TBI subjects reported that their injury predated the onset of their psychiatric symptoms. These results suggest a possible role of TBI in psychiatric symptomatology and have implications for psychiatric treatment in this population.     

The Home Observation for Measurement of the Environment: A comment on Zimmerman's critique

This paper is a reply to an article in this journal by M. Zimmerman titled “The Home Observation for Measurement of the Environment: A Comment on Elardo and Bradley's Review”. We found Zimmerman's critique of our original review article (Developmental Review, 1981, 1, 113–145) to contain points which were well taken, and several which seemed pedantic. Specifically, we address his concerns about our discussion of the HOME scale's interrater reliability, test-retest stability, concurrent validity, and predictive validity; and we reply to his comments about the uses of the HOME scale for purposes of screening and matching environments.     

Economic substitutability of electrical brain stimulation, food, and water.

Concurrent variable-ratio schedules of electrical brain stimulation, food, and water were paired in various combinations as reinforcement of rats' lever presses. Relative prices of the concurrent reinforcers were varied by changing the ratio of the response requirements on the two levers. Economic substitutability, measured by the sensitivity of response ratio to changes in relative price, was highest with brain stimulation reinforcement of presses on both levers and lowest with food reinforcement of presses on one lever and water reinforcement of presses on the other. Substitutability with brain stimulation reinforcement of presses on one lever and either food or water reinforcement for presses on the other was about as high as with brain stimulation for presses on both levers. Electrical brain stimulation for rats may thus serve as an economic substitute for two reinforcers, neither of which is substitutable for the other.     

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.     

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.     

Infants’ behavioral styles in joint attention situations and parents’ socio-economic status

In this study the eco-cultural model of parenting (Keller, H. (2007). Cultures of infancy. Mahwah, NJ: Erlbaum) was applied to the study of joint attention behavior of children from families with different socio-economic status (SES). It was hypothesized that infants’ early communication styles would differ with SES reflecting more independent or interdependent interactions with their caregivers. It was also hypothesized that infants would use the same types of behaviors whether they have declarative or imperative communication goals. The Early Social Communication Scales (ESCS, Mundy et al., 2003) was administered to 103 typically developing infants of 12 months (approximately half of them siblings of children with autism). A factor analysis, yielding four behavioral factors, namely pointing, eye contact, actions and following points, confirmed the hypothesis that infants use behaviors consistently across situations independent of their communicative intent. MANOVAs (comprising parental education and income) revealed that higher SES infants showed actions more frequently in the ESCS whereas lower SES infants followed experimenter's points more frequently. The results are discussed in the context of presumably differing socialization goals for infants and the divergent contribution of parental education and income that seem to have additive contribution to some factors (actions, following points) but divergent contributions to others (pointing, eye contact).