Line bisection performance in right-handed primary headache sufferers.

CONTEXT: In previous studies, patients with migraine and tension-type headaches have shown asymmetries at the central nervous system level. AIMS: Hence we would like to figure out whether the lateral cerebral dominance might be more pronounced in the line bisection performance with these patients. SETTINGS AND DESIGN: Patients were enrolled in a specialized headache clinic and healthy volunteers from a community as controls. MATERIALS AND METHODS: The visual line bisection is used to test the unilateral neglect of subjects. Altogether, we studied 28 patients with chronic tension-type, 16 frequent episodic tension-type headache, 31 migraine patients without aura between attacks and 146 healthy volunteers. STATISTICAL ANALYSIS: One-way ANOVA was applied to the mean Index and Net of line bisection errors and the Spearman rank order to the relationship between the Index, Net, subject's age and time since onset of head pain. RESULTS AND CONCLUSIONS: As reflected by group means of Index of line bisection errors, healthy subjects and migraine patients bisected slightly rightward. Conversely, both forms of tension-type headache sufferers bisected significantly leftward compared to the healthy subjects as well as the migraine sufferers. The study indicates relatively strong right or weak left hemisphere activation or both in the two forms of tension-type headaches, confirming the central nervous system alterations in such patients.

Selective potentiation of proximal processes: neurobiological mechanisms for spread of activation.

BACKGROUND: Signal detection by one sense selectively activates other relevant systems. For example, when an auditory stimulus comes from a specific location, visual sensitivity, tactile sensitivity, and motor readiness increase for stimuli or actions in that direction. This observed phenomenon provides an apparent sensory-sensory and sensory-motor coordination with evolutionary adaptive advantages. Anatomically, many of the relevant cortical sites are adjacent to each other. MATERIAL/METHODS: The spread of excitation from an active processing site in the cortex to nearby functions can be seen in brain scans. Cognitive and affective functions also selectively activate each other and are activated by focal sensory stimulation based on cortical proximity. These behavioral interactions seem to offer no selective adaptability but still call for a model of possible mediation. The objective of the current paper is to consider evidence for competing mechanisms for the flow of cortical activation that are characterized by being neurobiologically feasible, showing preferential activation over short distances, and having empirical support. RESULTS: These three criteria are met by blood flow, heat flow, nearest networks, electromagnetism, and inhibition. CONCLUSIONS: It is suggested that several of these mechanisms work independently or synergetically to produce the known interactions among attention, affect, cognition, and behavior. An understanding of these processes and the functional cerebral space in which they operate can suggest practical applications for the manipulation of behavior.

Line bisection performance in patients with personality disorders.

INTRODUCTION: Normal line bisection deviation to the left of the true centre has been interpreted as resulting from relative right hemisphere activation. Right hemisphere involvement has also been associated with the problems in dependency and attachment from infancy to adulthood. This hemispheric association predicts that patients diagnosed with dependent personality disorder will deviate significantly to the left on the line bisection task. METHODS: This hypothesis was tested by comparing the results of the line bisection task obtained respectively from 30 right-handed healthy volunteers and 14, 16, 18, and 26 outpatients with schizotypal, antisocial, borderline, and dependent personality disorders. Subjects completed eight horizontal line bisection tasks and the Dimensional Assessment of Personality Pathology-Basic Questionnaire (DAPP-BQ), a self-report measure of 18 traits delineating personality disorder. RESULTS: Patients with dependent personality disorder bisected significantly leftward compared to healthy controls. Dependent personality disorder patients scored significantly higher on DAPP-BQ Insecure Attachment, and lower on DAPP Stimulus Seeking, Callousness, Intimacy Problems, and Conduct Problems compared to the healthy controls and all other patient groups. CONCLUSIONS: Line bisection differentiates dependent personality disorder from other personality disorder diagnoses and healthy controls. This study thus suggests that line bisection can be used to enhance diagnostic specificity of dependent personality disorder and localises the brain areas implicated in the disorder.

Bisecting and behavior: lateral inattention predicts 8-week academic performance.

Converging evidence supports a left hemisphere role in defensive repression and sensation seeking. This led to the hypothesis that students with a relatively active left hemisphere would perform poorly during 8 weeks of a college class. The measure of relative hemispheric activation was the visual line-bisecting task given early in the course. The hypothesis was supported. Previous evidence that activation asymmetry is stable over time was supported because the single measurement of line bisecting was a longitudinal predictor of multiple behaviors. A temporal pattern of increasing correlation between the bisecting and performance measures favors a feedback repression model. Alternative explanations based on sensation seeking, subject-matter repression, and cooperation were considered but not eliminated.