Pain is more than a sensation processed by the peripheral nervous system. Pain engages the central nervous system via multiple cortical and subcortical networks. Neuropathic pain is a chronic pain resulting from damage to the somatosensory nervous system which can cause detrimental changes to physiological, psychological, and behavioral aspects of life. Neuropathic pain alters the structure, chemistry, and connectivity of medial prefrontal cortex (mPFC) in humans. Importantly, circuits comprising the mPFC are essential in processing emotional components of our everyday experiences, and therefore, are implicated in the affective component, or unpleasantness, of pain. A comprehensive understanding is lacking regarding the functionality of pain- relevant circuitry in the mPFC under normal conditions and in animal models of neuropathic pain. Therefore, this proposal seeks to understand the organization and function of both intracortical (local) and subcortical (long-range) synaptic inputs to a major population of mPFC neurons with specific targeting to a key subcortical pain structure: the periaqueductal gray (PAG). The PAG is a link in the primary pain-modulating network essential for endogenous analgesia and autonomic response to pain. Our objectives are 1) to elucidate the local and long-range circuitry of cortico-PAG neurons in the mPFC and 2) to assess the specific mechanisms by which the neural elements of cortico-PAG circuitry are altered by neuropathic pain. To accomplish these goals, we will develop a multifaceted approach involving retrograde labeling, electrophysiology, circuit mapping, optogenetic and behavioral techniques. The rationale for the proposed research is that identifying the neural mechanisms through which neuropathic pain alters circuit function in cognitive and emotional networks of the brain (specifically mPFC-PAG) will produce critical knowledge regarding the affective dimension of pain. Such an understanding can lead to novel strategies for therapeutic intervention. Our findings will contribute new and important insights into cellular and circuit mechanisms for how neuropathic pain alters specific cortical networks essential in the perception and emotional relevance of pain.
Neuropathic pain is a significant unresolved medical problem that is refractory to traditional analgesics and can negatively affect emotional health. To date, science has not produced a detailed elucidation of the circuitry involved in the physiological and emotional response to pain. The goal of this project is to identify the neural mechanisms through which neuropathic pain alters circuit function in cognitive and emotional networks of the brain thereby producing critical knowledge regarding the affective dimension of pain and pain disorders that could lead to novel strategies for therapeutic intervention.
|Cheriyan, John; Sheets, Patrick L (2018) Altered Excitability and Local Connectivity of mPFC-PAG Neurons in a Mouse Model of Neuropathic Pain. J Neurosci 38:4829-4839|
|Cheriyan, John; Kaushik, Mahesh K; Ferreira, Ashley N et al. (2016) Specific Targeting of the Basolateral Amygdala to Projectionally Defined Pyramidal Neurons in Prelimbic and Infralimbic Cortex. eNeuro 3:|