The aftermath of 9/11: effect of intensity and recency of trauma on outcome

Does trauma exposure have a long-term impact on the brain and behavior of healthy individuals? The authors used functional magnetic resonance imaging to assess the impact of proximity to the disaster of September 11, 2001, on amygdala function in 22 healthy adults. More than three years after the terrorist attacks, bilateral amygdala activity in response to viewing fearful faces compared to calm ones was higher in people who were within 1.5 miles of the World Trade Center on 9/11, relative to those who were living more than 200 miles away (all were living in the New York metropolitan area at time of scan). This activity mediated the relationship between group status and current symptoms of posttraumatic stress disorder. In turn, the effect of group status on both amygdala activation (fearful vs. calm faces) and current symptoms was statistically explained by time since worst trauma in lifetime and intensity of worst trauma, as indicated by reported symptoms at time of the trauma. These data are consistent with a model of heightened amygdala reactivity following high-intensity trauma exposure, with relatively slow recovery.     

Are historic years understood as numbers or events? An fMRI study of numbers with semantic associations

While numbers generally cue processing of quantity or order, they can also contain semantic information, as in the case of historic years (e.g., “1492” calls forth associations of Columbus sailing the ocean blue). Whether these dates are processed as quantities or events may depend on the context in which they occur. We examined such “ambiguous number” processing in two different contexts using a paired-comparison task, recording both behavioral responses and brain activity. Participants were either asked to think of all items as numbers and to choose the larger number, or were told to treat the comparators as events and to choose the later event. Behaviorally, all events showed a normal distance effect, establishing that they may be understood and compared in an ordinal sequence. Functional magnetic resonance imaging (fMRI) demonstrated significant differences between years when treated as numbers versus as events. Dates in both contexts shared activity in parietal lobe regions previously implicated in number processing. Dates as numbers showed no extra-numeric activity, while dates thought of as events evoked activity in temporal semantic processing and frontal semantic retrieval areas. These differences suggest that extra-numeric information may be easily accessed and incorporated during processing when supported by even a weak context. This work supports previous studies showing a dissociation between quantity and meaning, and illustrates the brain areas involved in these different aspects.     

Gender Symmetry and Asymmetry in Violent Relationships: Patterns of Mutuality Among Racially Diverse Women

Three patterns of mutual intimate partner violence (IPV) are proposed, based on frequency and severity: Male primary perpetrator (MPP), female primary perpetrator (FPP), and symmetrical (SYM). Patterns and effects of ethnicity were examined with 445 African American, Euro-American, and Mexican American low-income women experiencing mutual IPV. More relationships were classified as MPP (54%) than SYM (35%) or FPP (11%). Comparing women's and men's perpetration of several types of IPV (e.g., threats, severe physical) indicated MPP-pattern women experienced all IPV types more often and were more likely to sustain injury than their male partners. Fewer gender differences were found in the FPP pattern. Racial/ethnic groups were more similar than different; previously reported differences may be explained by variation in socioeconomic status. The larger part of the study was funded by grant R49/CCR610508 from the National Center for Injury Prevention and Control of the Centers for Disease Control and Prevention, awarded to the third author. This article was also made possible by grant 2001-WT-BX-0504 from the National Institute of Justice awarded to the first and third authors. These agencies are not responsible for the results. Portions of this paper were presented by the first and third authors at the International Family Violence Conference in Portsmouth, NH, July, 2003.     

Discriminative performance of the domestic hen in a visual acuity task

The performance of 6 domestic hens on a visual acuity task was studied using a spatial discrete-trial conditional discrimination procedure. Gray stimuli and vertical square-wave gratings, ranging in spatial frequency from 1 to 10 cycles per millimeter, were presented in a descending and ascending series of probes. On each trial, either a grating or gray stimulus was presented. Only one spatial frequency of grating was presented during each session. Between probe sessions, training continued at the coarsest grating value. Stimulus discriminability, measured as values of log d, changed with changes in grating spatial frequency for both probe series. Fitted lines described the linear portion of the psychometric functions. Thresholds estimated from the lines generally ranged from four to six cycles per degree, with slightly greater estimates from data from the descending probe series. There were no systematic changes in response bias as a function of grating spatial frequency.     

A further study of language function in callosal agenesis

A subset of the tests of language ability administered by M. Dennis (1981, Brain and Language, 12, 33-53) was given to two adult acallosal patients. One of the patients studied showed widespread language deficits not restricted to the syntactic-pragmatic core as in Dennis' patient. The other showed a very specific deficit which does not encompass syntactic-pragmatic skills. The data does not support the view that the corpus callosum is necessary for the normal development of specific language functions.