Temporal organization of the brain: Neurocognitive mechanisms and clinical implications

The synchrony between the individual brain and its environment is maintained by a system of internal clocks that together reflect the temporal organization of the organism. Extending the theoretical work of Edelman and others, the temporal organization of the brain is posited as functioning through "re-entry" and "temporal tagging" and binds the wide range of possible times to a unified cognitive experience which is held in unison with the outside world. Dysfunction in this system is reflected in the temporal discord seen in cases of aging, sleep disorder, jet-lag, and shift-work, as well as in mental disorders and drug-induced changes in consciousness. The extent to which neuroendocrine structures contribute to the neurocognitive mechanisms which underlie consciousness has so far not been explored. Therefore, neuroendocrine mechanisms contributing to the temporal organization of the brain are reviewed. It is concluded that time-and its neuroendocrine correlate melatonin-is a binding principle for organizing conscious experience.     

Do women with fragile X syndrome have problems in switching attention: preliminary findings from ERP and fMRI

Fragile X syndrome (FXS) is a neurodevelopmental disorder that represents the most common known cause of developmental delay. Recent neuropsychological findings indicate that females with FXS present with a specific pattern of cognitive deficits and that these difficulties primarily involve skills requiring executive control. The present study is the first to examine the extent to which neural activity of females with FXS can be observed on a task that specifically taps two core deficits, namely switching and response inhibition. Brain activity was measured using both event-related electrical potentials (ERPs) and event-related functional MRI (fMRI) neuroimaging in separate studies using the same cognitive paradigm. Compared to controls, females with FXS were significantly slower and made more errors on trials that required an immediate response (Go) to stimulus onset but were comparable on trials that required a delayed response (Wait) to stimulus onset. At the brain level, several areas showed significantly greater activation for females with FXS compared with controls, including the cingulate cortex and left and right ventral prefrontal areas. In contrast, no areas were found to show significantly greater activation for controls compared with females with FXS.     

Ethnic and cultural variations in anger regulation and attachment patterns among Korean American and European American male batterers

This study examined relationships among ethnicity, self-construals, and 2 risk factors for marital violence (anger, insecure attachment) in Korean American and European American male batterers. Korean (vs. European) American batterers experienced more anger and controlled their anger less. Independent self-construal was positively associated with anger experience and anger control and mediated the influence of ethnicity on anger control. Korean batterers were less independent, and less independent batterers controlled their anger less. Korean batterers' attachment styles were more avoidant and less anxious. Independent and interdependent self-construals were negatively associated with anxious and avoidant attachment, respectively. Independent self-construal mediated the influence of ethnicity on avoidant attachment. Clinical severity and adherence to traditional gender roles may help explain these ethnic and cultural variations.     

Asian American multidimensional acculturation scale: development, factor analysis, reliability, and validity

This article describes the development and psychometric properties of the Asian American Multidimensional Acculturation Scale (AAMAS). The results of 3 separate studies provide strong evidence of the instrument's reliability and validity. The principles for the development of the AAMAS were orthogonality of cultural dimensions, inclusion of a pan-ethnic Asian American dimension, and ease of use across ethnic groups. Exploratory and confirmatory factor analyses indicate that within each cultural dimension (AAMAS-Culture of Origin, AAMAS-Asian American, and AAMAS-European American) there are 4 reliable acculturation domains of cultural identity, language, cultural knowledge, and food consumption. These features of the AAMAS allow for a more complex assessment of acculturation level of Asian Americans and its relationship to psychological functioning.     

Laterality effects in the recognition of depth-rotated novel objects

The dissociable neural subsystems theory proposes that left-hemisphere (LH) performance is dominated by a viewpoint-invariant (VI) recognition subsystem, whereas right-hemisphere (RH) performance is dominated by a viewpoint-dependent (VD) subsystem (Marsolek, 1999). Studies supporting this theory have used familiar objects and, therefore, may have been confounded by characteristics beyond perceptual features. Experiment 1, a lateralized sequential-matching task with novel objects, showed VD recognition in both hemispheres. In Experiment 2, some participants learned semantic associations for four novel objects, whereas others were exposed to the novel objects without the semantic associations. Both groups later performed a depth-rotated lateralized sequential-matching task. The participants who had learned semantic associations showed greater VD performance in the RH than in the LH; however, the participants in the control group showed equivalent VD performance in both hemispheres. The results suggest that hemispheric differences in VD performance may be partially attributable to an LH advantage for semantic processing.     

The unbearable lightness of priming

Repetition priming from text to isolated words has been difficult to observe. One explanation for this difficulty is that previous attempts to observe this type of priming have utilised conditions that normally reduce priming. Two experiments were conducted to evaluate this hypothesis. Experiment 1 involved participants being presented with words in isolation and in text passages. The words were then presented again in a lexical decision test. Results indicated that priming occurred as a result of exposure to both isolated words and words in text, although priming was greater in the word-word condition. Experiment 2 investigated whether priming occurred in a lexical decision test on words that had been read prior to the test in Milan Kundera's novel "The Unbearable Lightness of Being." There was some evidence that participants who had read the book recently were faster at lexical decision to words from the book than participants who had not read the book. The two experiments therefore indicate that priming can occur from text to isolated words, although it is smaller in magnitude to that observed from word to word. Reasons for this difference, as suggested by Kirsner and Speelman (J. Exp. Psychol.: Learn. Mem. Cogn. 22 (1996) 563) model of repetition priming, are discussed.     

Tangible pictures: viewpoint effects and linear perspective in visually impaired people

Perception of raised-line pictures in blindfolded-sighted, congenitally blind, late-blind, and low-vision subjects was studied in a series of experiments. The major aim of the study was to examine the value of perspective drawings for haptic pictures and visually impaired individuals. In experiment 1, subjects felt two wooden boards joined at 45 degrees, 90 degrees, or 135 degrees, and were instructed to pick the correct perspective drawing from among four choices. The first experiment on perspective found a significant effect of visual status, with much higher performance by the low-vision subjects. Mean performance for the congenitally blind subjects was not significantly different from that of the late-blind and blindfolded-sighted subjects. In a further experiment, blindfolded subjects drew tangible pictures of three-dimensional (3-D) geometric solids, and then engaged in a matching task. Counter to expectations, performance was not impaired for the 3-D drawings as compared with the frontal viewpoints. Subjects were also especially fast and more accurate when matching top views. Experiment 5 showed that top views were easiest for all of the visually impaired subjects, including those who were congenitally blind. Experiment 5 yielded higher performance for 3-D than frontal viewpoints. The results of all of the experiments were consistent with the idea that visual experience is not necessary for understanding perspective drawings of geometrical objects.     

Relations among children's perceptions of maternal behavior,attributional styles,and behavioral symptomatology in maltreated children

This investigation examined relations among perceptions of mothers, attributional style, and counselor-rated behavior problems in 187 school age children (88 maltreated, 99 nonmaltreated). Hypotheses regarding the presence of higher levels of internalizing and externalizing behavior problems in maltreated children were confirmed. Attributional style was found to function as a moderator of externalizing behavior problems, suggesting that attributional style exerts a protective role against the harmful effect of child maltreatment. Perceptions of mothers were found to operate as a mediator of both internalizing and externalizing symptomatology, with maltreated children with less positive perceptions of their mothers exhibiting greater internalizing and externalizing behavior problems. These findings advance knowledge of how cognitive processes contribute to behavior problems in maltreated children and possess implications for prevention and intervention efforts.