Behavior In Healthy Individuals Research Articles

P111. Brain volume differences between healthy females with high and low emphatic behavior

Introduction Empathizing is the ability to identify the mental states of others, for predicting their behavior and responding with appropriate emotion. Two routes to empathy are discussed: One relatively automatically process, with fast emotional responding and late appraisal. A second way is less automatic with early cognitive appraisal. Brain areas with structural changes related to empathy comprising regions from the mirror neuron system (MNS) and the default mode network (DMN). Positive and negative associations between empathizing and regional gray matter (GM) volume were found in healthy controls in the left inferior frontal gyrus (IFG), insula and superior temporal sulcus. Facing these divergent correlative effects, we compared GM volume of healthy females with low and high empathic behavior. Methods From a sample of 269 female healthy students completing the Empathy Quotient (EQ), 20 individuals with EQ > 45 (mean age 22.8) were compared with 20 age-matched individuals with an EQ p p Results In the region-of-interest-based analysis, none of the regions was showing a significant group difference. The exploratory voxelwise analysis yielded clusters of reduced GM volume in the LE group in right and more prominent in left frontal, bilateral occipital and temporal regions, comprising the left middle and superior frontal gyrus, the right middle and inferior temporal gyrus, the bilateral IFG, fusiform gyrus, lingual gyrus and cerebellum. For the HE group, the most prominent cluster of reduced GM volume comprising the right parahippocampus, temporal inferior gyrus and cerebellum. Another cluster was consisting of voxels from the left insula, superior temporal gyrus, rolandic operculum and superior part of temporal pole and clusters were also found in the right caudate and less pronounced in the left middle occipital lobe and in the right superior medial frontal gyrus. Discussion We did not find any group effects in the region-of-interest-based analysis. Most likely are variations in normal empathic behavior in healthy individuals associated with localized sub-regional brain structure differences. Indeed, the exploratory voxel-wise approach revealed that both groups show different clusters of altered GM volume. The HE group showed increased GM volume in frontal regions, comprising MNS and in lateral occipital and temporal regions associated with social recognition. Regions with increased GM volume were found in regions related to reconstructive empathy (left insula and right parahippocampal gyrus) in the LE group.

A Role for the Medial Temporal Lobe in Feedback-Driven Learning: Evidence from Amnesia

The ability to learn from feedback is a key component of adaptive behavior. This type of learning is traditionally thought to depend on neural substrates in the striatum and not on the medial temporal lobe (MTL). Here we show that in humans the MTL becomes necessary for feedback-based learning when feedback is delayed. Specifically, amnesic patients with MTL damage were impaired at probabilistic learning of cue-outcome associations when response-contingent feedback was delayed by a few seconds, but not when feedback was immediate. By contrast, patients with striatal dysfunction due to Parkinson's disease demonstrated the opposite pattern: impaired learning when trial-by-trial feedback was immediate but not when feedback was delayed, indicating that the striatum is necessary for learning only when feedback is immediate. Together, these results reveal that multiple complementary learning processes support what appears to be identical behavior in healthy individuals and point to an important role for the MTL in feedback-driven learning.

Can cerebellar transcranial direct current stimulation become a valuable neurorehabilitation intervention?

Can cerebellar transcranial direct current stimulation become a valuable neurorehabilitation intervention?

Abnormal Vocal Cord Function in Difficult-to-Treat Asthma

Upper airway dysfunction may complicate asthma but has been largely ignored as an etiological factor. Diagnosis using endoscopic evaluation of vocal cord function is difficult to quantify, with limited clinical application. A novel imaging technique, dynamic 320-slice computerized tomography (CT), was used to examine laryngeal behavior in healthy individuals and individuals with asthma. Vocal cord movement was imaged using 320-slice CT larynx. Healthy volunteers were studied to develop and validate an analysis algorithm for quantification of normal vocal cord function. Further studies were then conducted in 46 patients with difficult-to-treat asthma. Vocal cord movement was quantified over the breathing cycle by CT using the ratio of vocal cord diameter to tracheal diameter. Normal limits were calculated, validated, and applied to evaluate difficult-to-treat asthma. Vocal cord movement was abnormal with excessive narrowing in 23 of 46 (50%) patients with asthma and severe in 9 (19%) patients (abnormal > 50% of inspiration or expiration time). Imaging also revealed that laryngeal dysfunction characterized the movement abnormality rather than isolated vocal cord dysfunction. Noninvasive quantification of laryngeal movement was achieved using CT larynx. Significant numbers of patients with difficult-to-treat asthma had excessive narrowing of the vocal cords. This new approach has identified frequent upper airway dysfunction in asthma with potential implications for disease control and treatment.

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.

EXECUTIVE PERSONALITY TRAITS AND EATING BEHAVIOR

Eating disorders, such as anorexia, bulimia, and binge eating disorder, commonly involve a dysregulation of behavior (e.g., a lack or excess of inhibition and impulsive eating patterns) that is suggestive of prefrontal dysfunction. Functional neuro-imaging studies show that prefrontal-subcortical systems play a role in eating behavior and appetite in healthy individuals, and that people with eating disorders have altered activity in these systems. Eating behavior is often disturbed by illnesses and injuries that impinge upon prefrontal-subcortical systems. This study examined relationships between executive functioning and eating behavior in healthy individuals using validated behavioral rating scales (Frontal Systems Behavior Scale and Eating Inventory). Correlations demonstrated that increased dysexecutive traits were associated with disinhibited eating and greater food cravings. There was also a positive association with cognitive restraint of eating, suggesting that increased compensatory behaviors follow disinhibited eating. These psychometric findings reinforce those of other methodologies, supporting a role for prefrontal systems in eating

Effects of 30 Days of Undernutrition on Reaction Time, Moods, and Symptoms

Few modern studies have addressed the effects of undernutrition on the behavior of healthy individuals. This study, conducted as part of a test of a nutritionally balanced but calorie-deficient experimental ration, examined the effects of 30 days of undernutrition on healthy, physically active soldiers. Tests of reaction time and standardized questionnaires assessing mood and symptom parameters (known to be sensitive to nutritional and other factors) were administered prior to and following a 30-day field exercise. During the exercise, 17 soldiers consumed a calorie-deficient, lightweight ration (LW group, 1946 kcal/day) and 17 consumed a calorie-adequate control ration (FN group, 2782 kcal/day). Mean energy expenditure for both groups was 3200–3300 kcal/day. There were no differences between the two diet groups on any of the measures of reaction time, mood, or symptoms after 30 days of ration consumption. Additionally, there were no adverse changes in reaction time performance from pre- to post-testing. Adverse changes in moods and symptoms were seen in both groups at the conclusion of the test, possibly because of the rigors of living in the field for an extended period of time. This study demonstrates that, in healthy individuals, various aspects of mental performance, mood, and symptoms are not affected by up to 30 days of moderate undernutrition.