F.H. WIllard, Ph.D.Anatomy Section

University of New EnglandCollege of Osteopathic Medicine

Biddeford, Maine, U.S.A.

The Neurophysiology of AcupuncturePossible Mechanisms and Outcomes

Quiroz-Gonzalez, S., S. Torres-Castillo, R.E. Lopez-Gomez, and I. Jimenez Estrada. 2017. Acupuncture Points and Their Relationship with Multireceptive Fields of Neurons. J Acupunct Meridian Stud. 10:81-89.

Acupuncture Channels

Primary Afferent Fibers

Prechtl and Powley, Behav. Brain Sci. 13:289-331, 1990

Sensitized Primary Afferent Fibers

Histamine Bradykinin Prostaglandins

Small Fiber Neurogenic Inflammatory Cycle

Spinal Cord

Neuropeptides+

Tissue Inflammation

Central Sensitization - Somatic

Quiroz-Gonzalez, S., S. Torres-Castillo, R.E. Lopez-Gomez, and I. Jimenez Estrada. 2017. Acupuncture Points and Their Relationship with Multireceptive Fields of Neurons. J Acupunct Meridian Stud. 10:81-89.

Central Sensitization - Visceral

Text

Large Fiber Touch

Small Fiber

Gate-ControlTheory

Large Fiber Touch

Small Fiber

Loss of Inhibition on the Segment

Neuropathic Pain

Visceral input

Somatic input

Viscerosomatic Integration - The Viscerotome

Cross-Sensitizationin the Dorsal Horn

Quiroz-Gonzalez, S., S. Torres-Castillo, R.E. Lopez-Gomez, and I. Jimenez Estrada. 2017. Acupuncture Points and Their Relationship with Multireceptive Fields of Neurons. J Acupunct Meridian Stud. 10:81-89.

ViscerosomaticIntegration & Acupuncture

Points

ViscerosomaticReceptive Fields

ReciprocalSensitization

Primary Afferent Fibers Central Processes

Tract of Lissauer

Quiroz-Gonzalez, S., S. Torres-Castillo, R.E. Lopez-Gomez, and I. Jimenez Estrada. 2017. Acupuncture Points and Their Relationship with Multireceptive Fields of Neurons. J Acupunct Meridian Stud. 10:81-89.

ViscerosomaticIntegration

ofAcupuncture

Points

BidirectionalCommunication

ReferredPain

Pancreaticosomatic Reflexes

• Stimulation of the pancreatic duct with trypsin

• Enhance EMG activity in the acromiotrapezius muscle of the back

Hoogerwerf et al,. Trypsin mediates nociception via the proteinase-activated receptor 2: a potentially novel role in pancreatic pain. Gastroenterol. 127 (3):883-891, 2004.

Referred Gall Bladder Pain

M. A. Giamberardino, G. Affaitati, and R. Costantini. Referred pain from internal organs. Hdbk Clin.Neurol. 81 (3rd Series):343-361, 2006

Trophic Changes

• Increased thickness of the subcutaneous tissue

• Firmness not related to edema

• Decreased thickness in the associated muscle layers

• Muscle atrophy

• Degree of change related to duration of painful episodes

M. A. Giamberardino, G. Affaitati, and R. Costantini. Referred pain from internal organs. Hdbk Clin.Neurol. 81 (3rd Series):343-361, 2006

Referred Uterine Pain

Referred Pain From The Uterus

• Rats pretreated with Evans Blue vital dye

• Subjected to noxious uterine stimulation

• Extravasation of dye over the low abdomen and back, sacral and perineal region

• U. Wesselmann and J. Lai. Mechanisms of referred visceral pain: uterine inflammation in the adult virgin rat results in neurogenic plasma extravasation in the skin. Pain 73 (3):309-317, 1997.

Uterus

Spinal Cord

Cutaneous Blood Vessel

Extravasation

Autonomic Reflex

Uterus

Spinal Cord

Extravasation Cutaneous Blood Vessel

Dorsal Root Reflex

Cross-sensitization of Pelvic Organs

Winnard KP, Dmitrieva N, Berkley KJ. 2006. Cross-organ interactions between reproductive, gastrointestinal, and urinary

tracts: modulation by estrous stage and involvement of the hypogastric nerve. Am.J.Physiol Regul.Integr.Comp Physiol

291: R1592-R601

Spinal cord as anintegrator of afferent

fibers

Ascending Nociceptive Pathways

Farquhar-Smith WP. 2009. Anatomy, physiology and pharmacology of pain.

Anaesthesia and Intensive Care Medicine 9: 3-7

Brainstem-Subcortical Thalamocortical

Control of Spinal Cord Activity

Descending Spinal Control SystemsEndogenous Pain Control

Raphe-spinal systemNoradrenergic-spinal system

Diffuse Noxious Inhibitory Control

Spino-Reticulospinal Loop

Limbic Forebrain

Hypothalamus

PAG

Medullary or SpinalDorsal Horn

Emotions Hormones

Raphe

Somaticactivity

PeripheralNerve

NeuropeptidesGABA

OpioidsGABA

SerotoninNorepinephrine

EAA

PeriaqueductalGray

PAG

IC

OpioidSystems

Naloxone Sensitive

Insular Cortex

Cingulate Gyrus, Medial Prefrontal Lobe,

& Amygdala

Dorsolateral PrefrontalCortex

Pain Neuromatrix

Pain Neuromatrix

Kucyi A, Davis KD. 2015. The dynamic pain connectome. Trends Neurosci 38: 86-95

Pain Connectome

Bai L, Qin W, Tian J, et al. Acupuncture modulatesspontaneous activities in the anticorrelated resting brainnetworks. Brain Res 2009;1279:37–49.

Hui KK, Liu J, Makris N, et al. Acupuncture modulates thelimbic system and subcortical gray structures of the humanbrain: evidence from fMRI studies in normal subjects. HumBrain Mapp 2000;9:13–25.

Wu MT, Sheen JM, Chuang KH, et al. Neuronal specificity ofacupuncture response: a fMRI study with electroacupuncture.NeuroImage 2002;16:1028–37.

Acupuncture Can Influence Cerebral Cortical Activity

Following acupuncture needle stimulation, activation in the sensorimotor cortical network, including the insula, thalamus, anterior cingulate cortex, and primary and secondary somatosensory cortices, and deactivation in the limbic-paralimbic neocortical network, including the medial prefrontal cortex, caudate, amygdala, posterior cingulate cortex, and parahippocampus, were detected and assessed

Functional MRI Studies

Lin, Y.J., Y.Y. Kung, W.J. Kuo, D.M. Niddam, C.C. Chou, C.M. Cheng, T.C. Yeh, J.C. Hsieh, and J.H. Chiu. 2016. Effect of acupuncture 'dose' on modulation of the default mode network

of the brain. Acupunct Med. 34:425-432.

TNA and SNA+MS induced DMN-insula activity and extensive DMN activity compared to SNA, despite comparable levels of de qi sensation. The TNA and SNA+MS groups exhibited a delayed and enhanced modulation of the DMN, which was not observed followed SNA and TENS. Furthermore, TNA increased precuneus activity and increased the DMNrelated activity of the cuneus and left insula, while SNA+MS increased activity in the right insula.

Zou, Y., W. Tang, X. Li, M. Xu, and J. Li. 2019. Acupuncture Reversible Effects on Altered Default Mode Network of Chronic Migraine Accompanied with Clinical Symptom Relief. Neural

Plast. 2019:5047463

HC CM - Pretreatment CM - Post-treatment

Quiroz-Gonzalez, S., S. Torres-Castillo, R.E. Lopez-Gomez, and I. Jimenez Estrada. 2017. Acupuncture Points and Their Relationship with Multireceptive Fields of Neurons. J Acupunct Meridian Stud. 10:81-89.

Cerebral Cortex

Brainstem

Spinal Cord

Peripheral Nerve

The Neurophysiology of Acupuncture