Sham or real—Post hoc estimation of stimulation condition in a randomized transcranial magnetic stimulation trial

Selecting a suitable sham condition within the frame of repetitive transcranial magnetic stimulation (rTMS) treatment trials is a central issue. On the one hand, the ideal sham condition should not have a real stimulation effect; on the other hand, it should not be recognized as sham by patients, particularly when considering that real stimulation conditions come along with rTMS specific side effects. Within the course of a multi-centre trial assessing the antidepressant effects of rTMS, patients were randomized to sham or real stimulation, in both cases using a standard stimulation coil. In one centre, patients (n = 33) were asked about their impression whether they received the sham or the real treatment, and if they would recommend the treatment to others. 29 patients returned the questionnaires and were included into the analysis. From 15 subjects with real stimulation, 11 suggested to have obtained real, and 4 to have obtained sham. From 14 sham stimulated subjects, 9 suggested to have obtained the real condition and 5 to have been sham stimulated. This difference was not significant (p = 0.60, chi square test). In addition, the major part of patients in both stimulation conditions would recommend rTMS to others. In both conditions, real and sham, the majority of subjects believed to have obtained the real condition. This implies suitability of the sham condition used since subjects appeared not to be able to identify the condition. The results imply the feasibility of a valid sham condition with a “real” coil

Auctioning Incentive Contracts: An Experimental Study

In this note, we experimentally examine the relative performance of price-only auctions and multi-attribute auctions. We do so in procurement settings where the buyer can give the winning bidder incentives to exert effort on non-price dimensions after the auction. Both auctions theoretically implement the surplus maximizing mechanism. Our experiment confirms this result. Moreover, we observe that the "pie" is shared the same in both auctions between buyer and suppliers both in theory and in the lab (after accounting for learning effects).Key words: Procurement; Price-only auctions; Multi-attribute auctions; Incentive Contracts; Laboratory Experimen

New Insights into Alzheimer's Disease Progression: A Combined TMS and Structural MRI Study

BACKGROUND: Combination of structural and functional data of the human brain can provide detailed information of neurodegenerative diseases and the influence of the disease on various local cortical areas. METHODOLOGY AND PRINCIPAL FINDINGS: To examine the relationship between structure and function of the brain the cortical thickness based on structural magnetic resonance images and motor cortex excitability assessed with transcranial magnetic stimulation were correlated in Alzheimer's disease (AD) and mild cognitive impairment (MCI) patients as well as in age-matched healthy controls. Motor cortex excitability correlated negatively with cortical thickness on the sensorimotor cortex, the precuneus and the cuneus but the strength of the correlation varied between the study groups. On the sensorimotor cortex the correlation was significant only in MCI subjects. On the precuneus and cuneus the correlation was significant both in AD and MCI subjects. In healthy controls the motor cortex excitability did not correlate with the cortical thickness. CONCLUSIONS: In healthy subjects the motor cortex excitability is not dependent on the cortical thickness, whereas in neurodegenerative diseases the cortical thinning is related to weaker cortical excitability, especially on the precuneus and cuneus. However, in AD subjects there seems to be a protective mechanism of hyperexcitability on the sensorimotor cortex counteracting the prominent loss of cortical volume since the motor cortex excitability did not correlate with the cortical thickness. Such protective mechanism was not found on the precuneus or cuneus nor in the MCI subjects. Therefore, our results indicate that the progression of the disease proceeds with different dynamics in the structure and function of neuronal circuits from normal conditions via MCI to AD

Transcranial Magnetic Stimulation Intensities in Cognitive Paradigms

BACKGROUND: Transcranial magnetic stimulation (TMS) has become an important experimental tool for exploring the brain's functional anatomy. As TMS interferes with neural activity, the hypothetical function of the stimulated area can thus be tested. One unresolved methodological issue in TMS experiments is the question of how to adequately calibrate stimulation intensities. The motor threshold (MT) is often taken as a reference for individually adapted stimulation intensities in TMS experiments, even if they do not involve the motor system. The aim of the present study was to evaluate whether it is reasonable to adjust stimulation intensities in each subject to the individual MT if prefrontal regions are stimulated prior to the performance of a cognitive paradigm. METHODS AND FINDINGS: Repetitive TMS (rTMS) was applied prior to a working memory task, either at the 'fixed' intensity of 40% maximum stimulator output (MSO), or individually adapted at 90% of the subject's MT. Stimulation was applied to a target region in the left posterior middle frontal gyrus (pMFG), as indicated by a functional magnetic resonance imaging (fMRI) localizer acquired beforehand, or to a control site (vertex). Results show that MT predicted the effect size after stimulating subjects with the fixed intensity (i.e., subjects with a low MT showed a greater behavioral effect). Nevertheless, the individual adaptation of intensities did not lead to stable effects. CONCLUSION: Therefore, we suggest assessing MT and account for it as a measure for general cortical TMS susceptibility, even if TMS is applied outside the motor domain

Age-related differences in breast cancer treatment

Background: More than half of the cases of breast cancer treated in the United States occur in women over age 65. This study investigates age-related differences in breast cancer therapy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41398/1/10434_2006_Article_BF02303540.pd

Asymmetrical frontal resting-state beta oscillations predict trait aggressive tendencies and behavioral inhibition

Contains fulltext : 119564.pdf (publisher's version ) (Open Access)Asymmetrical patterns of frontal cortical activity have been implicated in the development and expression of aggressive behavior. Along with individual motivational tendencies, the ability to restrain one's impulses might be a factor in aggressive behavior. Recently, a role for the inhibitory cortical beta rhythm was suggested. The present study investigated whether individual differences in resting state asymmetries in the beta frequency band were associated with trait aggression and behavioral inhibition. In addition, the selective contributions of the prefrontal and motor cortex areas to these associations were examined. Results showed that relative dominant right frontal beta frequency activity was associated with both heightened trait aggression, especially hostility, and reduced response inhibition. Moreover, asymmetries over the anterior electrode locations proved to be related most closely to trait aggression, while asymmetries over the central electrode locations were associated with response inhibition. Together these findings show that right-dominant frontal beta activity is positively associated with aggressive tendencies and reduced behavioral inhibition.8 p