title: Distinct brain mechanisms support spatial vs temporal filtering of nociceptive information.
abstract: The role of endogenous analgesic mechanisms has largely been viewed in the context of gain modulation during nociceptive processing. However, these analgesic mechanisms may play critical roles in the extraction and subsequent utilization of information related to spatial and temporal features of nociceptive input. To date, it remains unknown if spatial and temporal filtering of nociceptive information is supported by similar analgesic mechanisms. To address this question, human volunteers were recruited to assess brain activation with functional magnetic resonance imaging during conditioned pain modulation (CPM) and offset analgesia (OA). CPM provides one paradigm for assessing spatial filtering of nociceptive information while OA provides a paradigm for assessing temporal filtering of nociceptive information. CPM and OA both produced statistically significant reductions in pain intensity. However, the magnitude of pain reduction elicited by CPM was not correlated with that elicited by OA across different individuals. Different patterns of brain activation were consistent with the psychophysical findings. CPM elicited widespread reductions in regions engaged in nociceptive processing such as the thalamus, insula, and secondary somatosensory cortex. OA produced reduced activity in the primary somatosensory cortex but was associated with greater activation in the anterior insula, dorsolateral prefrontal cortex, intraparietal sulcus, and inferior parietal lobule relative to CPM. In the brain stem, CPM consistently produced reductions in activity, while OA produced increases in activity. Conjunction analysis confirmed that CPM-related activity did not overlap with that of OA. Thus, dissociable mechanisms support inhibitory processes engaged during spatial vs temporal filtering of nociceptive information.
authors.affiliation: Laboratory of Clinical Neurophysiology, Technion Faculty of Medicine, Haifa, Israel Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1010, USA Department of Neurology, Rambam Health Care Campus, Haifa, Israel Department of Physical Therapy, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel.
authors.forename: Hadas
authors.initials: H
authors.lastname: Nahman-Averbuch
authors.forename: Katherine T
authors.initials: KT
authors.lastname: Martucci
authors.forename: Yelena
authors.initials: Y
authors.lastname: Granovsky
authors.forename: Irit
authors.initials: I
authors.lastname: Weissman-Fogel
authors.forename: David
authors.initials: D
authors.lastname: Yarnitsky
authors.forename: Robert C
authors.initials: RC
authors.lastname: Coghill
mesh_terms: D000328:Adult; D000344:Afferent Pathways / Q000098:blood supply / Q000502:physiology*; D000698:Analgesia / Q000523:psychology*; D000704:Analysis of Variance; D001921:Brain / Q000098:blood supply / Q000502:physiology*; D001931:Brain Mapping; D003213:Conditioning, Psychological / Q000502:physiology; D005260:Female; D005528:Foot / Q000294:innervation; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D059225:Nociception / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010147:Pain Measurement; D011601:Psychophysics; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: CPM; Conditioned pain modulation; Offset analgesia