What was the question? fMRI and inference in psychophysiology.

fMRI research has spent its first generation determining areas of high activation in the brain during various psychological tasks. The technique has proved exceedingly useful for asking where is the brain active during these tasks. This paper investigates the utility of asking the question "where is the brain active" and provides the reader with a useful analogy to simplify the logic and decisions being made when doing fMRI research. Rationales are considered for asking both the questions: "where is the brain active" and "how does the brain work?"

The influence of facial feedback on race bias.

Two studies were conducted to examine whether facial feedback can modulate implicit racial bias as assessed by the Implicit Association Test (IAT). Participants were surreptitiously induced to smile through holding a pencil in their mouth while viewing photographs of unfamiliar Black or White males or performed no somatic configuration while viewing the photographs (Study 1 only). All participants then completed the IAT with no facial manipulation. Results revealed a spreading attitude effect, with significantly less racial bias against Blacks among participants surreptitiously induced to smile during prior viewing of Black faces than among participants surreptitiously induced to smile during prior viewing of White faces.

Temporal pattern of odor administration alters hemispheric processing in humans.

Evidence from a variety of sensory modalities has suggested that the left hemisphere may be 'tuned' to process more rapidly changing stimuli than the right and some have suggested that this difference forms the foundation of the functional dichotomy often drawn between the two hemispheres. Odors may be thought to engage these same temporally dependent processes as portions of an odor mixture may come to be transduced into a phasic series of neural events. Using brain electrical activity, we show that the temporal sequence of the odor alters the pattern of brain electrical activity. Estimates of the source localization for this activity indicate that rapidly changing odors, like sounds, visual and tactile stimuli, show increased activity in the left hemisphere.

Odor mixture alters neural resources during symbolic problem solving.

The smell of a cup of coffee is produced by many different odor chemicals combined in a mixture, yet the perception of that odor is of a single unified whole. Recent evidence has demonstrated that mixtures of odors share some of the same spatiotemporal features of speech sounds and may use similar brain resources in associating those features with the symbols they represent. This experiment investigated the hypothesis that an odor mixture would interfere with a math task that requires symbolic but not spatial processing. Results indicated the pattern of brain electrical activity was similar for the single odors and the mixture during spatial processing. During solution of the task requiring symbolic processing, the odor mixture produced a pattern of brain electrical activity different from the single odorants. These data suggest that the perception of odor mixtures may use some of the same resources associated with symbolic processing.

Potential health effects of odor from animal operations, wastewater treatment, and recycling of byproducts.

Complaints of health symptoms from ambient odors have become more frequent in communities with confined animal facilities, wastewater treatment plants, and biosolids recycling operations. The most frequently reported health complaints include eye, nose, and throat irritation, headache, nausea, diarrhea, hoarseness, sore throat, cough, chest tightness, nasal congestion, palpitations, shortness of breath, stress, drowsiness, and alterations in mood. Typically, these symptoms occur at the time of exposure and remit after a short period of time. However, for sensitive individuals such as asthmatic patients, exposure to odors may induce health symptoms that persist for longer periods of time as well as aggravate existing medical conditions. A workshop was held at Duke University on April 16-17, 1998 cosponsored by Duke University, the Environmental Protection Agency (EPA). and National Institute on Deafness and Other Communication Disorders (NIDCD) to assess the current state of knowledge regarding the health effects of ambient odors. This report summarizes the conclusions from the Workshop regarding the potential mechanisms responsible for health symptoms from ambient odors. Methods for validation of health symptoms, presence of odor, and efficacy of odor management techniques are described as well.

Just because you're imaging the brain doesn't mean you can stop using your head: a primer and set of first principles.

Developments within the neurosciences, cognitive sciences, and social sciences have contributed to the emergence of social neuroscience. Among the most obvious contemporary developments are brain-imaging procedures such as functional magnetic resonance imaging. The authors outline a set of first principles designed to help make sense of brain-imaging research within the fields of cognitive and social neuroscience. They begin with a principle few would debate--that social cognition, emotion, and behavior involve the brain--but whose implications might not be entirely obvious to those new to the field. The authors conclude that (a). complex aspects of the mind and behavior will benefit from yet a broader collaboration of neuroscientists, cognitive scientists, and social scientists, and (b). social psychologists bring important theoretical, methodological, and statistical expertise to this interdisciplinary enterprise.

Reduction of Sucrose Reward to Smaller and Nonreward Levels without Contrast Effects.

Five groups of albino rats were trained in a straight runway for 44 pre-shift trials, 2 trials per day with a 3- to 5-min intertrial interval (ITI). Two of the groups (30-0 and 30-3) received 1 ml of 30% sucrose solution as a reward, two groups (3-0 and 3-3) received an equal volume of 3% sucrose, and one group (0-0) received no reward. During 20 postshift trials, three groups (0-0, 3-0, and 30-0) received no reward, and two groups (3-3 and 30-3) received 3% sucrose. Postshift trials were massed (10/day) with the same ITI as in preshift. The reward shift produced a direct relationship between the amount of preshift reward and resistance to extinction and no evidence of successive negative contrast whether the shift was to smaller or non-reward levels.