Spinal cord response to stepwise and block presentation of thermal stimuli: A functional MRI study

Abstract

Purpose To examine the characteristics of the spinal cord and brainstem blood oxygenation level-dependent (BOLD) responses to peripheral stimulation in which the temperature is raised in a stepwise fashion, in order to enhance receptor responses, compared to a block design. Materials and Methods Functional magnetic resonance imaging (fMRI) studies of the spinal cord and brainstem were carried out in 14 healthy volunteers at 3T. Thermal sensory stimuli were applied to the right hand in a block-design paradigm, and in a stepwise paradigm to the same peak temperature. Data were analyzed by means of a general linear model, region of interest analyses, and by structural equation modeling. Results Results demonstrated BOLD responses in a number of consistent regions between the two paradigms as well as significant differences (P 2) between regions were observed in the block condition. Conclusion Results from this study demonstrate the means to design thermal sensory paradigms to probe components of sensory processing in the brainstem and spinal cord. J. Magn. Reson. Imaging 2015;41:1318-1325.