BRAIN MECHANISMS SUPPORTING EXPECTATION AND TOP-DOWN ATTENTION TO PAINFUL STIMULI

Top-down influences such as expectation and attention may powerfully modulate both sensory experience and related processing in the brain. In pain, top-down information such as expectations of lower pain or placebo treatments significantly reduces both subjective reports of experienced pain and pain-related brain activity. On another hand, top-down influences may be relevant to the development and maintenance of chronic pain states. In many instances, this top-down modulation is initiated by environmental cues. However, the exact sequence and specificity of events by which an environmental cue is transformed into neural activity that modulates sensory processing remains poorly understood. In this work we: a) explore commonalities and differences in neural processing of cues coming from different sensory modalities, b) identify the neural substrates of spatial and intensity top-down attention in nociception, and c) explore the effects of top-down attention on the activity in relationship to stimulus processing areas both before and during stimulus presentation. We used functional magnetic resonance imaging to assess brain activations and deactivations during and following presentation of different types of cues to human subjects. We found that processing related to cue meaning extraction and implementation is independent of the sensory modality of the cue. Superior parietal lobule/precuneus, dorsolateral prefrontal cortex (DLPFC) and cerebellum were implicated in these processes. In addition, attention to spatial and intensity features of pain activated intraparietal sulcus and frontal eye fields. These areas likely activated brain areas that were relevant to impending processing (primary somatosensory cortex, dorsal and ventral information streams) and deactivated brain areas that were irrelevant to such processing (the default mode network) in turn. Together, these studies contribute to a better understanding of how external cues are transformed into top-down directives in pain. It is likely that the mechanisms described in the present work are not limited to nociceptive processing alone but also extend into other sensory domains.

Grantor dc:publisher

Wake Forest University

Year dc:date.issued

2012

Author dc:creator

• Lobanov, Oleg V.

• Attention

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/10339/37278

OAI identifier oai:identifier

oai:wakespace.lib.wfu.edu:10339/37278