Altered spinal cord activity during sexual stimulation in women with SCI: a pilot fMRI study

Abstract

INTRODUCTION:The objective of this study was to assess the feasibility of the use of functional magnetic resonance imaging (fMRI) to evaluate the spinal activation during sexual response of the thoracic, lumbar and sacral spinal cord. MATERIALS AND METHODS: This is a laboratory-based pilot study in human females at a University-based medical center in the United States. In three healthy spinal cord injury (SCI) females, spinal cord activations during sexual audiovisual stimulation (alone), genital self-stimulation (alone) and simultaneous audiovisual and genital self-stimulation (combined) were assessed and then compared with each subjects' remaining sensory and motor function. RESULTS: Spinal fMRI responses of the intermediolateral columns were found during audiovisual stimulation in both subjects with incomplete injuries, but they were not observed in the subject with a complete injury. Moreover, sacral responses to combined stimulation differed greatly between the subjects with complete and incomplete injuries. CONCLUSION: These results not only provide the first in vivo documentation of spinal fMRI responses associated with sexual arousal in women with SCIs, but also suggest that spinal cord fMRI is capable of distinguishing between injury subtypes. Therefore, although there are certain limitations associated with fMRI during sexual stimulation (for example, movement artifacts, an artificially controlled environment and so), these findings demonstrate the potential utility of incorporating spinal cord fMRI in future research to evaluate the impact of specific patterns of SCI on sexual responses and/or the effects of treatment.

Ten Key Insights into the Use of Spinal Cord fMRI

“…While SCI is the most widely-studied patient population when using spinal fMRI, this technology has also been used to identify differences in spinal cord activity in response to different stimuli in multiple sclerosis [ 64 ], to characterize spinal cord responses to heat pain in fibromyalgia [ 53 ], and to show resting-state spinal cord activity differences in patients with cervical spondylotic myelopathy compared to healthy controls [ 65 ]. A recent case study was also reported in which the investigators examined activity in response to painful stimuli in a patient with referred pain [ 66 ].…”

“…The two most commonly used methods, GE-EPI and HASTE, demonstrate two very different strategies to achieve this balance. Spinal fMRI with HASTE methods (or variations of single-shot fast spin-echo) have been reported with repetition times of between 4.8 s and 9 s, with values around 6–7 s being the most common [ 22 , 23 , 24 , 25 , 28 , 31 , 33 , 34 , 36 , 37 , 41 , 42 , 44 , 45 , 47 , 48 , 49 , 53 , 54 , 55 , 56 , 57 , 60 , 61 , 62 , 63 , 64 , 66 , 76 , 77 , 79 , 80 , 81 , 82 , 85 , 87 , 88 , 97 , 102 , 103 ]. In most cases, data are acquired in sagittal slices and cover a large volume of the spinal cord.…”

“…The results showed different magnitudes of BOLD responses that corresponded with ratings of sensation/pain, and specific right dorsal and left ventral regions responding within specific spinal cord segments (C6 to C8). More recent studies using HASTE methods with sagittal slices, 1.5 × 1.5 × 2 mm 3 resolution, have shown anatomical details of locations responding to sexual stimulation in the lumbar spinal cord in both healthy participants and three cases of women with spinal cord injury [ 54 , 55 , 64 ]. In addition, a number of studies of pain processing with similar methods have shown detailed responses in the cervical spinal cord to noxious heat stimulation and pain modulation by individual differences [ 44 ], spinal cord injury [ 62 ], temporal summation [ 42 ], and music [ 47 ].…”

Effect of Physiological Noise on Thoracolumbar Spinal Cord Functional Magnetic Resonance Imaging in 3T Magnetic Field

“…Previous research suggested that the lumbar spinal cord is motionless and the noise fitting can be ignored (Figley, Yau, & Stroman, 2008). Others only considered the cardiac motion-related effects on the spinal cord and CSF (Alexander et al, 2017;Alexander et al, 2016;R. Bosma & Stroman, 2015;Kozyrev et al, 2012), and both these approaches may lead to biased information due to ignoring the respiration noise as one of the main sources of noise production.…”

“…Functional Magnetic Resonance Imaging (fMRI) methods have been used to study sensorimotor processing in the brain and the spinal cord. Nowadays, spinal cord fMRI studies have investigated spinal cord in several pathologic conditions such as spinal cord injury ( Alexander, Kozyrev, Figley & Richards, 2017 ; Cadotte et al, 2012 ; Chen, Mishra, Yang, Wang, & Gore, 2015 ; Chen, Kong, Wang, Xie, & Wu, 2007 ; Choe, 2017 ; Stroman et al, 2004 ; Stroman et al, 2016 ; Zhong et al, 2017 ), multiple sclerosis ( Agosta et al, 2009 ; Agosta, Valsasina, Caputo, Stroman, & Filippi, 2008 ; Agosta et al, 2008 ; Kearney, Miller, & Ciccarelli, 2015 ; Rocca et al, 2012 ; Valsasina et al, 2010 ; Valsasina et al, 2012 ), chronic and neuropathic pain ( Bosma et al, 2016 ; Leitch, Cahill, Ghazni, Figley, & Stroman, 2009 ), all of which need consistent and sensitive clinical results. However, there are numerous challenges for spinal cord fMRI which arises from the nature of spinal cord: bony structure of the vertebral canal; movement of the cord and adjacent tissues due to physiological processes such as swallowing, breathing, and so on; the CSF flux in the subarachnoid space circumambient the spinal cord; small cross-sectional dimensions of the spinal cord and; changing in the susceptibility of tissues due to breathing and bulk motion ( Brooks et al, 2008 ; Fratini, Moraschi, Maraviglia, & Giove, 2014 ; Stroman et al, 2014 ; Verma & Cohen-Adad, 2014 ).…”