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Journal Article 2007; 28(2): 121-130 PubMed PMID: 17435676 Citation  Keywords:  Animals, Conditioning (Psychology), Dental Pulp:innervation, Electroshock, Evoked Potentials, Somatosensory:physiology, Jaw, Male, Movement, Pain Measurement, Rats, Rats, Sprague-Dawley, Reflex, Tooth, Wakefulness,.   

OBJECTIVE: Investigation of pain and nociception refers to different models. Depending upon the intensity of stimulation, unmyelinated pulpal fibers or periodontal A-fibers can be stimulated producing a short or a long latency jaw opening reflex of the digastric muscle. This paper investigates the different components of the jaw opening reflex in addition to the correlation between afferent fibers involved in the cortical evoked response.

DESIGN AND SETTING: Fifteen awake male rats were implanted with tooth pulp stimulation electrodes, digastric and cortical recording electrodes. Ten rats were submitted to recordings after a single tooth pulp stimulation, while five rats were using conditioning and test stimulation. Tooth pulp evoked potentials and digastric EMG were simultaneously recorded. A multiresolution denoising method was used for signal processing.

RESULTS: Following tooth pulp stimulation, a cortical response was produced including the following peaks: P6.5 +/- 1.1, N11 +/- 1.2, P17 +/- 1.2, P27 +/- 2.9, N53 +/- 7.5, P69 +/- 5.8, P88 +/- 13, N160 +/- 9.7, P204 +/- 14.2. The distribution and amplitude of these peaks are correlated to the stimulation intensity (r=0.96, p<0.01). An interaction between the different components of the jaw opening reflex was identified on EMG, following a conditioning shock, where a cortical evoked response showed a P30 +/- 2.7 peak which was observed concurrently with the jaw opening long latency reflex.

CONCLUSION: Our results identify the interaction between the different components of the jaw opening reflex and the correlation to the cortical evoked response....

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Clinical Trial 2005; 26(2): 143-147 PubMed PMID: 15855886 Citation  Keywords:  Adult, Cerebral Cortex:physiology, Diabetes Complications:physiopathology, Diabetes Mellitus, Type 2:complications, Diabetic Neuropathies:diagnosis, Evoked Potentials, Motor:physiology, Evoked Potentials, Somatosensory:physiology, Humans, Middle Aged, Neu.   

OBJECTIVES: Diabetic neuropathy and autonomic nervous system neuropathy are recognized as the most common clinical pictures of nervous system disorders caused by diabetes mellitus (DM). Damage to the brain and the spinal cord is rare. The aim of this work is to show the importance of somatosensory and motor evoked potentials (SEP and MEP) for the early diagnosis of nervous system damage related to diabetes mellitus.

MATERIAL AND METHODS: We examined spinal and cortical somatosensory evoked potentials (SEP) after median and fibular nerve stimulation in diabetics and control subjects. We measured the latencies of individual wave deflections and peripheral and central conduction time (PCT and CCT) of spinal and cortical SEP. Similarly, transcranial magnetic stimulation was used for measuring the central and peripheral conduction time (CCT and PCT) in a group of type 1 diabetics and a control group of volunteers.

RESULTS: The examination SEP and MEP proved and confirmed the prolongation not only of peripheral conduction time, but also of the central conduction time - especially in spinal cord structures. An assumption that spinal cord changes are connected with the decreased number of myelinated fibers able to conduct the impulses from periphery and brain cortex, respectively, has to be accepted.

CONCLUSIONS: The results suggest that the use of somatosensory and motor evoked potentials (SEP and MEP) examination and conduction times measurement has significance in the confirmation of unapparent lesions of the spinal cord in diabetics of both types....

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