There are two types of cells in the central nervous systems (CNS) of mammals-neurons and glia. The structure and function of neurons have been thoroughly studied; while the role of glia in information processing has not been systematically studied because they cannot produce action potentials like neuron. During the past decades, glial cells were considered to play a supportive role in CNS instead of information processing. Recently, a variety of studies suggest that glial cells are actively involved in the regulation of brain function associated with neurons. Glial cells, especially astrocytes play important roles in different sensory processing. In the present article, we review the role of astrocytes in sensory processing in the CNS.
Animals ; Astrocytes ; cytology ; physiology ; Central Nervous System ; physiology ; Humans ; Sensation ; physiology ; Synapses ; physiology

The physiological mechanism underlying the acupoint sensitization was evaluated systemically by using the method of electric physiology at spinal cord, medulla, and thalamus levels; the dynamic change of acupoint from the relative "silence" to the relative "activation" function was explained through the study on the dynamic process of acupoint sensitization; the biological process of the therapeutic effect of acupoint stimulation was illuminated through the research of the central mechanism underlining the dose effect relationship between the sensitive acupoint and the related brain area, thus scientific evidence for the functional link between the acupoint and internal organs as well as the nature of the acupoint were provided.
Acupuncture Points ; Acupuncture Therapy ; Animals ; Humans ; Moxibustion ; Nociceptors ; physiology ; Sensation ; Viscera ; innervation ; physiology ; Visceral Afferents ; physiology

Channels from the TRP superfamily have essential roles in a wide variety of sensory transductions, especially in mechano-sensation, such as hearing, touch and mechanical pain. TRP channels are also implicated in major channelopathies, including deafness, chronic pain, autosomal dominant polycystic kidney disease (ADPKD) and ventricular hypertrophy. As the leading candidates for mechano-sensitive channels, some TRP channels appear to be mechano-receptor, which can be activated by mechanical forces directly, such as C. elegans TRPN homolog TRP-4; whereas others may act as signal modulators, receiving and amplifying signals indirectly. This review is to introduce the function of TRPs in mechano-sensory transduction and to discuss the underlying molecular mechanisms.
Animals ; Humans ; Neural Conduction ; Sensation ; physiology ; Signal Transduction ; Transient Receptor Potential Channels ; metabolism ; physiology

Humans ; Irritable Bowel Syndrome ; physiopathology ; Sensation ; Serotonin ; physiology ; Signal Transduction ; Viscera ; physiology

OBJECTIVEEarly researches found that different heartbeat perceivers have different heartbeat evoked potential (HEP) waves. Two tasks were considered in our experiments to get more details about the differences between good and poor heartbeat perceivers at attention and resting state.

METHODSThirty channels of electroencephalogram (EEG) were recorded in 22 subjects, who had been subdivided into good and poor heartbeat perceivers by mental tracking task. Principal component analysis (PCA) was applied to remove cardiac field artifact (CFA) from the HEP.

RESULTS(1) The good heart-beat perceivers showed difference between attention and resting state in the windows from 250 ms to 450 ms after R wave at C3 location and from 100 ms to 300 ms after R wave at C4 location; (2) The difference waveforms between good and poor heartbeat perceivers was a positive waveform at FZ from 220 ms to 340 ms after R wave, which was more significant in attention state.

CONCLUSIONAttention state had more effect on the HEPs of good heartbeat perceivers than that of poor heartbeat perceivers; and perception ability influenced HEPs more strongly in the attention state than in the resting state.

Adult ; Afferent Pathways ; physiology ; Attention ; physiology ; Awareness ; physiology ; Biofeedback, Psychology ; physiology ; Brain ; physiology ; Electroencephalography ; Evoked Potentials ; physiology ; Heart ; physiology ; Heart Rate ; physiology ; Humans ; Male ; Perception ; physiology ; Reference Values ; Sensation ; physiology

Event-related potential (ERP) studies report that early components P120, N170 and VPP are associated with face processing. Several lines of evidence suggest that VPP is the positive counterpart of N170, and they are generated by the same brain sources. However, whether P120 has a negative counterpart and the relations among these early components (i.e. P120, N170, VPP) remain unclear. In this study, the scalp electroencephalogram was recorded when the subjects passively viewed different stimuli, and ERP was calculated. The synchronization of electroencephalography signals between fronto-central and bilateral occipitotemporal sites was evaluated, and independent component analysis was employed to seek the face-sensitive independent components and their corresponding sources. We found that P120 had the negative counterpart, i.e., VN120; moreover, VN120-VPP and P120-N170 complexes were generated by the same sources located in fusiform gyrus, which reflected the same sequential neural activities of face processing.
Adolescent ; Brain ; physiology ; Electroencephalography ; Evoked Potentials ; physiology ; Face ; Female ; Humans ; Male ; Pattern Recognition, Visual ; physiology ; Perception ; physiology ; Sensation ; physiology ; Young Adult

Anorectal manometry is now widely performed to evaluate anorectal physiology in a variety of clinical conditions. No adverse consequence related with this procedure has been reported yet. There has been no known guideline or precaution regarding the upper limit of the volume inflating the rectal balloon in measuring maximum tolerable volume. We experienced 2 cases of colorectal rupture during measuring maximum tolerable volume. Both cases were in their early postoperative period, 1 month after low anterior resection due to rectal cancer and 3 months after Delorme's procedure due to rectal prolapse, respectively. The rectal sensory and anorectal motor responses to rectal distension are known to depend on the rate and pattern of distension. Therefore, results of different examiners and laboratories cannot be compared directly unless the pattern and rate of distension are the same. Wide intersubject and intrasubject variations in maximum tolerable volume have been also reported, and differentiation between patients and normal subjects is not necessarily possible. Measuring maximum tolerable volume is painful and unpleasant, and some authors believe that maximum tolerable volume in addition to the other steps of rectal sensations does not contribute any additional information. Based on our experience and literature, we suggest that measuring maximum tolerable volume might be better to be omitted, or if it be done, rectal balloon should be inflated with great care especially in early postoperative period or in those who cannot feel or express their symptoms clearly, such as elderly or infants.
Aged ; Humans ; Infant ; Manometry* ; Physiology ; Postoperative Period ; Rectal Neoplasms ; Rectal Prolapse ; Rupture* ; Sensation

"Acupoints-brain relation hypothesis" is put forward according to the combination of cerebral functional imaging techniques, positron emission tomography (PET), single photon emission computed tomography (SPECT) and functional magnetic resonance imaging (fMRI), and the studies of the essence of acupoints. Analysis based on the living state of human being, the cerebral function and the objective images and data will result in: (1) a model of cerebral functional imaging for the definition of acupoints, any points that coincide the basic factors of the model can be definited as an acupoint; (2) a model of cerebral functional imaging for needling sensation, any cerebral functional changes caused by needling coincide the basic factors of the model can be definited as needling sensation; (3) a study on characteristics and regular patterns of association of the acupoints selected along channels.
Acupuncture Points ; Acupuncture Therapy ; Brain ; physiology ; Humans ; Medicine, Chinese Traditional ; Meridians ; Sensation

Propagated sensation along meridians (PSM) is a phenomenon that a sensation moves along meridians during stimulation of an acupoint. PSM has an appearance rate of 1.3% among people and have characteristics of low speed, going toward afflicted sites and being blocked by physical pressure which is difficult to be explained by known neural and blood transmission. Volume transmission (VT) is a widespread mode of intercellular communication in the central nervous system that occurs in the extracellular fluid and in the cerebrospinal fluid. VT signals moves from source to target cells via energy gradients leading to diffusion and convection (flow) which is slow, long distance and much less space filling. VT channel diffuse forming a plexus in the extracellular space with two parameters of volume fraction and tortuosity. Some experiments showed an information transmission between adjacent and distant acupoints along meridians cross spinal segments. This process is a cross-excitation between peripheral nerve terminals which is related to nonsynaptic transmission. Some neurotransmitters or neuropeptides such as glutamate, adenosine triphosphate (ATP) and neuropeptide such as substance P, neurokinin A and calcitonin gene-related peptide relate with the cross-excitation which can be regards as VT signals. Comparing the characteristics of PSM and VT, many similar aspects can be found leading to an assumption that PSM is a process of VT in peripheral tissue along meridians. The reason why VT signals transmit along meridians is that the meridian is rich in interstitial fluid under the condition of low hydraulic resistance which has been proven experimentally. According to Darcy's law which descript the flow of interstitial fluid and conservation equation, interstitial fluid will move toward meridians and flow along meridians that restrict the VT signals within the channel and accelerate the flow according to Fick's diffusion law. During the process, a degranulation of histamine from mast cells happens on the route which can expand capillary and increase the blood perfusion and interstitial fluid which had already been observed. The mechanism of PSM is featured by alternative axon reflex (wired transmission, WT) and VT in peripheral tissue along meridians, sending simultaneously a continuous sensate signal to control nerve system which can be felt like a PSM.
Cell Communication ; Humans ; Meridians ; Neurotransmitter Agents ; metabolism ; Organ Specificity ; Sensation ; physiology

Resection of oral and maxillofacial tumors is often accompanied by the inferior alveolar nerve neurectomy, resulting in abnormal sensation in lower lip. It is generally believed that spontaneous sensory recovery in this nerve injury is difficult. However, during our follow-up, patients with inferior alveolar nerve sacrifice showed different degrees of lower lip sensory recovery. In this study, a prospective cohort study was conducted to demonstrate this phenomenon and analyze the factors influencing sensory recovery. A mental nerve transection model of Thy1-YFP mice and tissue clearing technique were used to explore possible mechanisms in this process. Gene silencing and overexpression experiments were then conducted to detect the changes in cell morphology and molecular markers. In our follow-up, 75% of patients with unilateral inferior alveolar nerve neurectomy had complete sensory recovery of the lower lip 12 months postoperatively. Patients with younger age, malignant tumors, and preservation of ipsilateral buccal and lingual nerves had a shorter recovery time. The buccal nerve collateral sprouting compensation was observed in the lower lip tissue of Thy1-YFP mice. ApoD was demonstrated to be involved in axon growth and peripheral nerve sensory recovery in the animal model. TGF-β inhibited the expression of STAT3 and the transcription of ApoD in Schwann cells through Zfp423. Overall, after sacrificing the inferior alveolar nerve, the collateral compensation of the ipsilateral buccal nerve could innervate the sensation. And this process was regulated by TGF-β-Zfp423-ApoD pathway.
Mice ; Animals ; Lip/innervation* ; Prospective Studies ; Mandibular Nerve/pathology* ; Sensation/physiology* ; Trigeminal Nerve Injuries/pathology*