The primary somatosensory cortex (S1) projects to the thalamus and brainstem somatosensory nuclei... more The primary somatosensory cortex (S1) projects to the thalamus and brainstem somatosensory nuclei and modulates somatosensory information ascending to the S1 itself. However, the projections from the S1 to the brainstem second-order somatosensory neuron pools have not been fully studied. To address this in rats, we first revealed the somatotopic representation of orofacial areas in the S1 by recording cortical surface potentials evoked by stimulation of the lingual, mental, infraorbital, and frontal nerves. We then examined the morphology of descending projections from the electrophysiologically defined orofacial S1 areas to the pons and medulla after injections of an anterograde tracer, biotinylated dextranamine (BDA), into the orofacial S1 areas. BDA-labeled axon terminals were seen mostly in the trigeminal sensory nuclear complex (TSNC) and had a strong con-tralateral predominance. They also showed a somatotopic arrangement in dorsoventral and superficial-deep directions within almost all rostrocaudal TSNC levels, and in a rostrocaudal direction within the trigeminal caudal subnucleus. In the principal nucleus (Vp) or oral subnucleus (Vo) of TSNC, the BDA-labeled axon terminals showed a somatotopic arrangement closely matched to that of the electrophysiologically defined projection sites of orofacial primary afferents; these projection sites were marked by injections of a retrograde tracer, Fluorogold (FG), into the Vp or Vo. The FG injections labeled a large number of S1 neurons, with a strong contralateral predominance, in a somatotopic manner, which corresponded to that presented in the electrophysiologically defined orofacial S1 areas. The present results suggest that the orofacial S1 projections to somatotopically matched regions of trigeminal second-order somatosensory neuron pools may allow the orofacial S1 to accurately modulate orofacial somatosensory transmission to higher brain centers including the orofacial S1 itself.
The pesticide rotenone inhibits mitochondrial complex I and is thought to cause neurological diso... more The pesticide rotenone inhibits mitochondrial complex I and is thought to cause neurological disorders such as Parkinson’s disease and cognitive disorders. However, little is known about the effects of rotenone on conditioned taste aversion memory. In the present study, we investigated whether intranasal administration of rotenone affects conditioned taste aversion memory in mice. We also examined how the intranasal administration of rotenone modulates synaptic transmission and plasticity in layer V pyramidal neurons of the mouse insular cortex that is critical for conditioned taste aversion memory. We found that the intranasal administration of rotenone impaired conditioned taste aversion memory to bitter taste. Regarding its cellular mechanisms, long-term depression (LTD) but not long-term potentiation (LTP) was impaired in rotenone-treated mice. Furthermore, spontaneous inhibitory synaptic currents and tonic GABA currents were decreased in layer V pyramidal neurons of rotenone-tr...
Objectives The FTO gene has been reported as an obesity-associated gene and is also considered a ... more Objectives The FTO gene has been reported as an obesity-associated gene and is also considered a risk gene for osteoarthritis (OA). However, its exact function is unclear, and there is conflicting evidence on the involvement of FTO polymorphisms in OA via obesity. The purpose of this study was to determine the effects of FTO polymorphism rs8044769 alleles on OA in the temporomandibular joint (TMJ), which is minimally affected by body weight. Materials and methods A total of 324 TMJs (113 with OA and 211 without OA, serving as controls) from 162 Japanese patients with temporomandibular disorders and undergoing MRI examination were analyzed. Genotyping was conducted, and multivariate analysis was performed after adjusting for the effects of age, sex, body mass index, and TMJ disc abnormalities. Results Mean age, BMI, and sex did not differ between the TMJs with OA and the TMJs without OA, but a significant difference was found for positional and dynamic disc abnormalities (P < 0.05...
Introduction: Sleep habits are known to have a profound cultural influence, with great variation ... more Introduction: Sleep habits are known to have a profound cultural influence, with great variation among populations. The aims of this study were: a) To describe the sleep habits and sleep disturbances of a pediatric population from Cabo Verde; b) Compare the results with those from other cultures. Methods: Cross-sectional survey, culminating in a correlational study. Data was collected between September and November of 2016 by conducting the Portuguese version of the Children's Sleep Habits Questionnaire (CSHQ). The interviews took place in surveillance appointments in primary care centres of São Vicente and the respondents were the parents of children between 2 and 15 years old. Total scores, subscale scores and item scores were obtained and analysed. The cutoff with the best diagnostic confidence was 56, as suggested by a ROC curve weighting both sensitivity and specificity equally. Internal consistency was assessed using Cronbach's alpha (a ¼ 0,77). The distribution of scores across subgroups of children differing by age, gender, existence of parent reported sleep problems, number of cohabitants, father and mother age and level of father and mother school years were compared using Mann-Whitney's U-Test or Kruskal-Wallis test. The Bonferroni correction was used to set the family-wise error rate at 0,05% (p< 0,001). Results: 206 complete questionnaires, response rate of 100%. The mean age was 6.6, and there were 95 males in the sample (46%). The mean CSHQ score was 52.72 (min 36; max 79; SD 8.82). The estimated prevalence of sleep disorders was 29,9% and the prevalence of parent reported sleep problems was 22,82%. The existence of parent reported sleep problems displayed positive sample correlation with all CSHQ subscale scores and with the CSHQ total score. The distributions of CSHQ total scores and subscale scores showed no statistical differences across gender or age. Significant differences were found between age subgroups in the items "goes to bed at same time", "needs parent in room to sleep", "sleep same amount each day", "wets bed at night", sleeps while "riding in car" (p< 0,001), with younger children having higher scores. The items "falls asleep in own bed" and "falls asleep in other's bed" presented better scores for higher levels of mother education (p< 0,001). During the week days, the average wake up time was 7:15 h (SD 1:02) and the average bedtime 20:30h (SD 0:57). The average number of total sleep hours was 12,5 (SD 2). As compared with Dutch, Chinese, North-American and Portuguese previous studies, our sample had higher CSHQ scores and increased total sleep hours. Conclusions: This was the first study about sleep habits in Cabo Verde. When compared to other cultures, this population scored higher in all CSHQ subscale scores, as well as in the CSHQ total score. The average sleep duration was higher than reported in other studies. Bedtime was delayed and sleep duration decreases with increasing age, as identified in previous studies. Cultural, social and environmental characteristics of sleep practices, such as co-sleeping and crowded housing, may contribute to higher CSHQ scores.
Concomitant occurrence of respiratory events can be often overlooked in the clinical practice of ... more Concomitant occurrence of respiratory events can be often overlooked in the clinical practice of SB. This study assessed physiological characteristics of rhythmic masticatory muscle activity (RMMA) and concomitant respiratory events in young SB subjects asymptomatic to obstructive sleep apnea (OSA). Twenty-two subjects (age: 24.1±1.9years; F 8: M 14; BMI: 20.2±1.9kg/m) were polysomnographically diagnosed as moderate-severe SB. Sleep architecture, oromotor (RMMA and non-specific masseter activity [NSMA]) and apnea/hypopnea events were scored. All subjects showed normal sleep architecture whereas 6 exhibited respiratory events at a mild level of OSA. In all subjects, RMMA predominantly occurred in Stage N1+N2 while NSMA occurred in Stage N1+N2 (approximately 60 %) and in Stage R (up to 30 %). Up to 50% of respiratory events were scored in Stage R. RMMA occurred more frequently in close association (e.g., within 10s) with respiratory events in 6 subjects with OSA than those without. Th...
Neuropathic pain is characterized by sensory abnormalities, such as mechanical allodynia and heat... more Neuropathic pain is characterized by sensory abnormalities, such as mechanical allodynia and heat hyperalgesia, associated with alteration in the peripheral and central nervous systems. After trigeminal nerve injury, phenotypic changes that involve the expression of calcitonin generelated peptide occur in large-and medium-sized myelinated neurons; primary afferent neurons exhibit hyperexcitability because of neuron-glia interactions in the trigeminal ganglion. Increased nociceptive inputs from C-and Aδ-fiber and innocuous inputs from Aβ-fiber into the trigeminal spinal subnucleus caudalis (Vc) contribute to the phenotypic changes; further, they potentiate noxious information transmission in the ascending nociceptive pathways to the thalamus and parabrachial nucleus (PBN). It is noteworthy that C-fiber mediated nociceptive inputs can activate both the Vc-ventral posteromedial thalamic nucleus and Vc-PBN pathways, while mechanoreceptive fiber inputs specifically activate the Vc-PBN pathway. The Vc-PBN pathways project to the central nucleus of the amygdala (CeA) where affective behaviors are modulated. In addition, the PBN interacts with wakefulness-regulating neurons and hunger-sensitive neurons in the hypothalamus, suggesting that the Vc-PBN pathway can modulate sleep and appetite. Therefore, phenotypic changes in primary neurons and stimulus modality-specific activation of ascending nociceptive pathways to the PBN may exacerbate affective aspects of trigeminal neuropathic pain, including behavioral problems, such as sleep disturbance and anorexia, via the PBN-CeA-hypothalamus circuits.
ght by N o t f o r Q u itessence ot for Pulication On July 1, 2008, just before the annual meetin... more ght by N o t f o r Q u itessence ot for Pulication On July 1, 2008, just before the annual meeting of the International Association of Dental Research (IADR), a symposium was hosted at the Faculty of Dentistry, University of Toronto, Canada. This special day was dedicated to recognize the contributions of 3 “giants” in oral and trigeminal neuroscience, and it attracted more than 180 clinicians and scientists. The symposium was sponsored by the IADR Neuroscience Group, Fonds de le Recherche en Santé du Québec (Oral Health and Bone Research Network; Québec Pain Research Network), Canadian Institutes for Health Research (Applied Oral Health Research, Pain M2C, and Cells Signals training grants, Placebo Mechanism Research Network), and Quintessence Publishing. Three articles that summarize the 6 to 7 tribute presentations for each giant are included in this issue of the Journal of Orofacial Pain. The 3 giants completed their dentistry training in Australia in the sixties and entered into PhD programs in Sydney, Australia, for Professor Barry Sessle (mentor Dr Ian Darian-Smith), in London, Ontario, Canada, for Professor Jim Lund (mentor Dr Peter Dellow), and in Bristol, England, for Professor Alan Hannam (mentor Dr Declan Anderson). It is very rewarding for Canada to have been able to attract these 3 young clinician-scientists who became prolific in their academic life. Over their careers, the 3 giants received numerous competitive research grants, and they have collectively trained more than 200 graduate students in Canada. A rapid Web search revealed hundreds of peer-reviewed journal articles, book contributions, and books published by them. Dr Sessle is professor and Canada research chair at the Faculty of Dentistry, University of Toronto, where he has been since 1971. He also served as dean of the Faculty from 1990 to 2001. He has been president of the IADR and of the International Association for the Study of Pain. He is a fellow of the Royal Society of Canada and member of the Canadian Academy of Science and is the current president of the Canadian Pain Society and editor-in-chief of the Journal of Orofacial Pain. His research interests have focused on the neural mechanisms underlying both pain and movement (mastication, swallowing). The Sessle Tribute was thus aptly titled From Pain to Movement and was arranged and chaired by Professor G. Lavigne (Université de Montréal). Dr Lund initiated his academic career at the Université de Montréal more than 30 years ago. For over 12 years, until May 2008, he was dean at the Faculty of Dentistry, McGill University, Montreal. Professor Lund was the first dental representative on the board of the Institute of Musculoskeletal Health of the Canadian Institutes of Health Research. His research interests were initially focused on the understanding of the genesis and control of masticatory movements, but in the last 2 decades he also has been interested in pain and in chewing rehabilitation in dentate patients, in collaboration with his wife, Professor Jocelyne Feine of McGill University. The Lund Tribute was thus appropriately titled From Movement to Pain and was arranged by Professor A. Kolta (Université de Montréal) and chaired by Professor M. C. Bushnell (McGill University). Dr Hannam began his academic career at the University of British Columbia where he was until recently professor in the Faculty of Dentistry. He also served as associate dean for graduate and postgraduate studies in that Faculty and is now professor emeritus. His research interests have been in muscle physiology and in modeling (imaging and mathematical approaches) of chewing function and occlusion. The Hannam Tribute was thus titled From Movement to Models. It was arranged by Professor C. Peck (University of Sydney, Australia) and was chaired by Professor S. Palla (University of Zurich, Switzerland). We would like to express our gratitude to the following persons or organizations that worked with us to ensure the success of the symposium: the Faculties of Dentistry at the University of Toronto, McGill University, and Université de Montréal; Drs G. Zarb, T. Dao, and T. Tobias for the special tribute that they paid the 3 giants during the symposium; and Ms C. Remo and R. Wagman and Drs L. Beaudriault and D. Mock for their behind-the-scenes organization and management of the symposium. Our 3 giants still remain very active in science but they also have other passions: Professor Sessle finds some relaxation when he plays tennis, travels, or spends time at his cottage; Professor Lund when he is visiting museums and gardening; and Professor Hannam when sailing in Vancouver. Professors Sessle, Lund, and Hannam, the Tribute was a unique temoignage to the gratefulness of your friends and past or current students devoted to you. Please continue to inspire the fields of orofacial pain and movement!
This study examined the projections from the rat insular cortex (Ins) to lower brainstem areas wh... more This study examined the projections from the rat insular cortex (Ins) to lower brainstem areas which are possibly involved in orofacial pain processing. We first examined distributions of Ins neurons projecting directly to the trigeminal caudal subnucleus (Vc, medullary dorsal horn) and oral subnucleus (Vo) which are known to receive orofacial nociceptive inputs. After injections of a retrograde tracer, Fluorogold (FG), into the medial part and lateral part of laminae I/II of Vc, many neurons were labeled bilaterally with a contralateral predominance in the rostral level of granular Ins (GI) and dysgranular Ins (DI) and the caudal level of GI/DI, respectively, but none in the agranular Ins (AI). After FG injections into laminae III-V of Vc, no Ins neurons were labeled. After FG injections into the Vo, many neurons were labeled bilaterally with a contralateral predominance in the rostral and caudal GI/DI, but none in the AI. We then examined descending projections from the GI/ DI to the lower brainstem. After injections of an anterograde tracer, biotinylated dextranamine (BDA), into the rostral GI/ DI, many BDA-labeled axons and terminals were seen bilaterally with a contralateral predominance in the medial part of laminae I/II of Vc, dorsomedial Vo, juxtatrigeminal region, rostral ventromedial medulla (RVM), and nucleus of the solitary tract, and with an ipsilateral predominance in the parabrachial nucleus (Pb), Kö lliker-Fuse nucleus (KF) and trigeminal mesencephalic nucleus. After BDA injections into the caudal GI/DI, they were seen bilaterally with a contralateral predominance in the lateral part of laminae I/II of Vc, ventrolateral Vo, juxtatrigeminal region and RVM, and with an ipsilateral dominance in the lateral zone (PAGl) of periaqueductal gray, Pb and KF. These results suggest that orofacial nociceptive processing of Vc and Vo neurons may be regulated by GI/DI directly or indirectly through brainstem nuclei such as PAGl, Pb, KF and RVM.
The roles of supramedullary brain mechanisms involved in the control of jaw movements are not ful... more The roles of supramedullary brain mechanisms involved in the control of jaw movements are not fully understood. To address this issue, a series of retrograde (Fluorogold, FG) and anterograde (biotinylated dextran amine, BDA) tract-tracing studies were done in rats. At first, we identified projection patterns from defined sensorimotor cortical areas to subgroups of trigeminal premotoneurons that are located in defined brainstem areas. Focal injections of FG into these brainstem areas revealed that the rostralmost part of lateral agranular cortex (rmost-Agl), the rostralmost part of medial agranular cortex (rmost-Agm), and the rostralmost
Study Objectives: Sleep bruxism (SB) is reported to vary in frequency over time. The aim of this ... more Study Objectives: Sleep bruxism (SB) is reported to vary in frequency over time. The aim of this study was to assess the fi rst night effect on SB. Methods: A retrospective polysomnographic (PSG) analysis was performed of data from a sample of SB patients (12 females, 4 males; age range: 17-39 years) recorded in a sleep laboratory over 2 consecutive nights. Sleep parameters and jaw muscle activity variables (i.e., rhythmic masticatory muscle activity [RMMA]) for SB were quantifi ed and compared between the 2 nights. Subjects were classifi ed into groups according to severity of RMMA frequency, such as low frequency (2-4 episodes/h and/or < 25 bursts/h) and moderatehigh frequency (≥ 4 episodes/h and ≥ 25 bursts/h). Results: Overall, no fi rst night effects were found for most sleep variables. However, total sleep time, sleep effi ciency, and stage transitions showed signifi cant time and group interactions (repeated measures ANOVAs, p ≤ 0.05). The RMMA episode index did not differ between the 2 nights, whereas the second night showed signifi cantly higher burst index, bruxism time index, and mean burst duration (repeated measure ANOVAs, p ≤ 0.05). Five patients of 8 in the low frequency group were classifi ed into the moderate-high frequency group on the second night, whereas only one patient in the moderate-high frequency group moved to the low frequency group. Conclusions: The results showed no overall fi rst night effect on severity of RMMA frequency in young and healthy patients with SB. In clinical practice, one-night sleep recording may be suffi cient for moderate-high frequency SB patients. However, low RMMA frequency in the fi rst night could be confi rmed by a second night based on the patient's medical and dental history.
Sleep bruxism (SB) is an unusual orofacial movement described as a parafunction in dentistry and ... more Sleep bruxism (SB) is an unusual orofacial movement described as a parafunction in dentistry and as a parasomnia in sleep medicine. Since several peripheral influences could be involved in sleep-wake regulation and the genesis of rhythmic jaw movements, the authors have reviewed the relevant literature to facilitate understanding of mechanisms possibly involved in SB genesis. Various animal and human studies indicate that during either wakefulness or anesthesia, orofacial sensory inputs (e.g., from periodontium, mucosa, and muscle) could influence jaw muscle activity. However, the role of these sensory inputs in jaw motor activity during sleep is unclear. Interestingly, during sleep, the jaw is usually open due to motor suppression; tooth contact most likely occurs in association with sleep arousal. Recent physiologic evidence supports an association between sleep arousal and SB; a sequential change from autonomic (cardiac) and brain cortical activities precede SB-related jaw motor ...
Sleep bruxism is a sleep-related movement disorder characterized by an exaggerated jaw motor acti... more Sleep bruxism is a sleep-related movement disorder characterized by an exaggerated jaw motor activity during sleep. Currently, the magnitude of jaw motor activation in normal sleep remains poorly understood. In this study, we aim to assess the state-dependent changes in the magnitude of electromyographic activities of the jaw-closing masseter muscle in comparison with those of a neck muscle (specifically, the obliquus capitis) during sleep-wake cycles in guinea pigs. These electromyographic activities were integrated for 10-s epochs during wakefulness, non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. The masseter activity per epoch was found to be five times lower in both sleep stages while the neck muscle activity also decreased to 30% in NREM sleep and was lowest (16%) in REM sleep. In the periods without motor activity, masseter tone did not differ between the three states, whereas neck muscle tone decreased from wakefulness to NREM sleep and further to REM sleep. Moreover, in the epochs with masseter activation, the neck muscle activity did not increase during sleep. These results suggest that masseter activity decreases but is occasionally activated during sleep, and that state-dependent changes in electromyographic activity can be differently modulated in time and intensity between the masseter and the obliquus capitis.
The primary somatosensory cortex (S1) projects to the thalamus and brainstem somatosensory nuclei... more The primary somatosensory cortex (S1) projects to the thalamus and brainstem somatosensory nuclei and modulates somatosensory information ascending to the S1 itself. However, the projections from the S1 to the brainstem second-order somatosensory neuron pools have not been fully studied. To address this in rats, we first revealed the somatotopic representation of orofacial areas in the S1 by recording cortical surface potentials evoked by stimulation of the lingual, mental, infraorbital, and frontal nerves. We then examined the morphology of descending projections from the electrophysiologically defined orofacial S1 areas to the pons and medulla after injections of an anterograde tracer, biotinylated dextranamine (BDA), into the orofacial S1 areas. BDA-labeled axon terminals were seen mostly in the trigeminal sensory nuclear complex (TSNC) and had a strong con-tralateral predominance. They also showed a somatotopic arrangement in dorsoventral and superficial-deep directions within almost all rostrocaudal TSNC levels, and in a rostrocaudal direction within the trigeminal caudal subnucleus. In the principal nucleus (Vp) or oral subnucleus (Vo) of TSNC, the BDA-labeled axon terminals showed a somatotopic arrangement closely matched to that of the electrophysiologically defined projection sites of orofacial primary afferents; these projection sites were marked by injections of a retrograde tracer, Fluorogold (FG), into the Vp or Vo. The FG injections labeled a large number of S1 neurons, with a strong contralateral predominance, in a somatotopic manner, which corresponded to that presented in the electrophysiologically defined orofacial S1 areas. The present results suggest that the orofacial S1 projections to somatotopically matched regions of trigeminal second-order somatosensory neuron pools may allow the orofacial S1 to accurately modulate orofacial somatosensory transmission to higher brain centers including the orofacial S1 itself.
The pesticide rotenone inhibits mitochondrial complex I and is thought to cause neurological diso... more The pesticide rotenone inhibits mitochondrial complex I and is thought to cause neurological disorders such as Parkinson’s disease and cognitive disorders. However, little is known about the effects of rotenone on conditioned taste aversion memory. In the present study, we investigated whether intranasal administration of rotenone affects conditioned taste aversion memory in mice. We also examined how the intranasal administration of rotenone modulates synaptic transmission and plasticity in layer V pyramidal neurons of the mouse insular cortex that is critical for conditioned taste aversion memory. We found that the intranasal administration of rotenone impaired conditioned taste aversion memory to bitter taste. Regarding its cellular mechanisms, long-term depression (LTD) but not long-term potentiation (LTP) was impaired in rotenone-treated mice. Furthermore, spontaneous inhibitory synaptic currents and tonic GABA currents were decreased in layer V pyramidal neurons of rotenone-tr...
Objectives The FTO gene has been reported as an obesity-associated gene and is also considered a ... more Objectives The FTO gene has been reported as an obesity-associated gene and is also considered a risk gene for osteoarthritis (OA). However, its exact function is unclear, and there is conflicting evidence on the involvement of FTO polymorphisms in OA via obesity. The purpose of this study was to determine the effects of FTO polymorphism rs8044769 alleles on OA in the temporomandibular joint (TMJ), which is minimally affected by body weight. Materials and methods A total of 324 TMJs (113 with OA and 211 without OA, serving as controls) from 162 Japanese patients with temporomandibular disorders and undergoing MRI examination were analyzed. Genotyping was conducted, and multivariate analysis was performed after adjusting for the effects of age, sex, body mass index, and TMJ disc abnormalities. Results Mean age, BMI, and sex did not differ between the TMJs with OA and the TMJs without OA, but a significant difference was found for positional and dynamic disc abnormalities (P < 0.05...
Introduction: Sleep habits are known to have a profound cultural influence, with great variation ... more Introduction: Sleep habits are known to have a profound cultural influence, with great variation among populations. The aims of this study were: a) To describe the sleep habits and sleep disturbances of a pediatric population from Cabo Verde; b) Compare the results with those from other cultures. Methods: Cross-sectional survey, culminating in a correlational study. Data was collected between September and November of 2016 by conducting the Portuguese version of the Children's Sleep Habits Questionnaire (CSHQ). The interviews took place in surveillance appointments in primary care centres of São Vicente and the respondents were the parents of children between 2 and 15 years old. Total scores, subscale scores and item scores were obtained and analysed. The cutoff with the best diagnostic confidence was 56, as suggested by a ROC curve weighting both sensitivity and specificity equally. Internal consistency was assessed using Cronbach's alpha (a ¼ 0,77). The distribution of scores across subgroups of children differing by age, gender, existence of parent reported sleep problems, number of cohabitants, father and mother age and level of father and mother school years were compared using Mann-Whitney's U-Test or Kruskal-Wallis test. The Bonferroni correction was used to set the family-wise error rate at 0,05% (p< 0,001). Results: 206 complete questionnaires, response rate of 100%. The mean age was 6.6, and there were 95 males in the sample (46%). The mean CSHQ score was 52.72 (min 36; max 79; SD 8.82). The estimated prevalence of sleep disorders was 29,9% and the prevalence of parent reported sleep problems was 22,82%. The existence of parent reported sleep problems displayed positive sample correlation with all CSHQ subscale scores and with the CSHQ total score. The distributions of CSHQ total scores and subscale scores showed no statistical differences across gender or age. Significant differences were found between age subgroups in the items "goes to bed at same time", "needs parent in room to sleep", "sleep same amount each day", "wets bed at night", sleeps while "riding in car" (p< 0,001), with younger children having higher scores. The items "falls asleep in own bed" and "falls asleep in other's bed" presented better scores for higher levels of mother education (p< 0,001). During the week days, the average wake up time was 7:15 h (SD 1:02) and the average bedtime 20:30h (SD 0:57). The average number of total sleep hours was 12,5 (SD 2). As compared with Dutch, Chinese, North-American and Portuguese previous studies, our sample had higher CSHQ scores and increased total sleep hours. Conclusions: This was the first study about sleep habits in Cabo Verde. When compared to other cultures, this population scored higher in all CSHQ subscale scores, as well as in the CSHQ total score. The average sleep duration was higher than reported in other studies. Bedtime was delayed and sleep duration decreases with increasing age, as identified in previous studies. Cultural, social and environmental characteristics of sleep practices, such as co-sleeping and crowded housing, may contribute to higher CSHQ scores.
Concomitant occurrence of respiratory events can be often overlooked in the clinical practice of ... more Concomitant occurrence of respiratory events can be often overlooked in the clinical practice of SB. This study assessed physiological characteristics of rhythmic masticatory muscle activity (RMMA) and concomitant respiratory events in young SB subjects asymptomatic to obstructive sleep apnea (OSA). Twenty-two subjects (age: 24.1±1.9years; F 8: M 14; BMI: 20.2±1.9kg/m) were polysomnographically diagnosed as moderate-severe SB. Sleep architecture, oromotor (RMMA and non-specific masseter activity [NSMA]) and apnea/hypopnea events were scored. All subjects showed normal sleep architecture whereas 6 exhibited respiratory events at a mild level of OSA. In all subjects, RMMA predominantly occurred in Stage N1+N2 while NSMA occurred in Stage N1+N2 (approximately 60 %) and in Stage R (up to 30 %). Up to 50% of respiratory events were scored in Stage R. RMMA occurred more frequently in close association (e.g., within 10s) with respiratory events in 6 subjects with OSA than those without. Th...
Neuropathic pain is characterized by sensory abnormalities, such as mechanical allodynia and heat... more Neuropathic pain is characterized by sensory abnormalities, such as mechanical allodynia and heat hyperalgesia, associated with alteration in the peripheral and central nervous systems. After trigeminal nerve injury, phenotypic changes that involve the expression of calcitonin generelated peptide occur in large-and medium-sized myelinated neurons; primary afferent neurons exhibit hyperexcitability because of neuron-glia interactions in the trigeminal ganglion. Increased nociceptive inputs from C-and Aδ-fiber and innocuous inputs from Aβ-fiber into the trigeminal spinal subnucleus caudalis (Vc) contribute to the phenotypic changes; further, they potentiate noxious information transmission in the ascending nociceptive pathways to the thalamus and parabrachial nucleus (PBN). It is noteworthy that C-fiber mediated nociceptive inputs can activate both the Vc-ventral posteromedial thalamic nucleus and Vc-PBN pathways, while mechanoreceptive fiber inputs specifically activate the Vc-PBN pathway. The Vc-PBN pathways project to the central nucleus of the amygdala (CeA) where affective behaviors are modulated. In addition, the PBN interacts with wakefulness-regulating neurons and hunger-sensitive neurons in the hypothalamus, suggesting that the Vc-PBN pathway can modulate sleep and appetite. Therefore, phenotypic changes in primary neurons and stimulus modality-specific activation of ascending nociceptive pathways to the PBN may exacerbate affective aspects of trigeminal neuropathic pain, including behavioral problems, such as sleep disturbance and anorexia, via the PBN-CeA-hypothalamus circuits.
ght by N o t f o r Q u itessence ot for Pulication On July 1, 2008, just before the annual meetin... more ght by N o t f o r Q u itessence ot for Pulication On July 1, 2008, just before the annual meeting of the International Association of Dental Research (IADR), a symposium was hosted at the Faculty of Dentistry, University of Toronto, Canada. This special day was dedicated to recognize the contributions of 3 “giants” in oral and trigeminal neuroscience, and it attracted more than 180 clinicians and scientists. The symposium was sponsored by the IADR Neuroscience Group, Fonds de le Recherche en Santé du Québec (Oral Health and Bone Research Network; Québec Pain Research Network), Canadian Institutes for Health Research (Applied Oral Health Research, Pain M2C, and Cells Signals training grants, Placebo Mechanism Research Network), and Quintessence Publishing. Three articles that summarize the 6 to 7 tribute presentations for each giant are included in this issue of the Journal of Orofacial Pain. The 3 giants completed their dentistry training in Australia in the sixties and entered into PhD programs in Sydney, Australia, for Professor Barry Sessle (mentor Dr Ian Darian-Smith), in London, Ontario, Canada, for Professor Jim Lund (mentor Dr Peter Dellow), and in Bristol, England, for Professor Alan Hannam (mentor Dr Declan Anderson). It is very rewarding for Canada to have been able to attract these 3 young clinician-scientists who became prolific in their academic life. Over their careers, the 3 giants received numerous competitive research grants, and they have collectively trained more than 200 graduate students in Canada. A rapid Web search revealed hundreds of peer-reviewed journal articles, book contributions, and books published by them. Dr Sessle is professor and Canada research chair at the Faculty of Dentistry, University of Toronto, where he has been since 1971. He also served as dean of the Faculty from 1990 to 2001. He has been president of the IADR and of the International Association for the Study of Pain. He is a fellow of the Royal Society of Canada and member of the Canadian Academy of Science and is the current president of the Canadian Pain Society and editor-in-chief of the Journal of Orofacial Pain. His research interests have focused on the neural mechanisms underlying both pain and movement (mastication, swallowing). The Sessle Tribute was thus aptly titled From Pain to Movement and was arranged and chaired by Professor G. Lavigne (Université de Montréal). Dr Lund initiated his academic career at the Université de Montréal more than 30 years ago. For over 12 years, until May 2008, he was dean at the Faculty of Dentistry, McGill University, Montreal. Professor Lund was the first dental representative on the board of the Institute of Musculoskeletal Health of the Canadian Institutes of Health Research. His research interests were initially focused on the understanding of the genesis and control of masticatory movements, but in the last 2 decades he also has been interested in pain and in chewing rehabilitation in dentate patients, in collaboration with his wife, Professor Jocelyne Feine of McGill University. The Lund Tribute was thus appropriately titled From Movement to Pain and was arranged by Professor A. Kolta (Université de Montréal) and chaired by Professor M. C. Bushnell (McGill University). Dr Hannam began his academic career at the University of British Columbia where he was until recently professor in the Faculty of Dentistry. He also served as associate dean for graduate and postgraduate studies in that Faculty and is now professor emeritus. His research interests have been in muscle physiology and in modeling (imaging and mathematical approaches) of chewing function and occlusion. The Hannam Tribute was thus titled From Movement to Models. It was arranged by Professor C. Peck (University of Sydney, Australia) and was chaired by Professor S. Palla (University of Zurich, Switzerland). We would like to express our gratitude to the following persons or organizations that worked with us to ensure the success of the symposium: the Faculties of Dentistry at the University of Toronto, McGill University, and Université de Montréal; Drs G. Zarb, T. Dao, and T. Tobias for the special tribute that they paid the 3 giants during the symposium; and Ms C. Remo and R. Wagman and Drs L. Beaudriault and D. Mock for their behind-the-scenes organization and management of the symposium. Our 3 giants still remain very active in science but they also have other passions: Professor Sessle finds some relaxation when he plays tennis, travels, or spends time at his cottage; Professor Lund when he is visiting museums and gardening; and Professor Hannam when sailing in Vancouver. Professors Sessle, Lund, and Hannam, the Tribute was a unique temoignage to the gratefulness of your friends and past or current students devoted to you. Please continue to inspire the fields of orofacial pain and movement!
This study examined the projections from the rat insular cortex (Ins) to lower brainstem areas wh... more This study examined the projections from the rat insular cortex (Ins) to lower brainstem areas which are possibly involved in orofacial pain processing. We first examined distributions of Ins neurons projecting directly to the trigeminal caudal subnucleus (Vc, medullary dorsal horn) and oral subnucleus (Vo) which are known to receive orofacial nociceptive inputs. After injections of a retrograde tracer, Fluorogold (FG), into the medial part and lateral part of laminae I/II of Vc, many neurons were labeled bilaterally with a contralateral predominance in the rostral level of granular Ins (GI) and dysgranular Ins (DI) and the caudal level of GI/DI, respectively, but none in the agranular Ins (AI). After FG injections into laminae III-V of Vc, no Ins neurons were labeled. After FG injections into the Vo, many neurons were labeled bilaterally with a contralateral predominance in the rostral and caudal GI/DI, but none in the AI. We then examined descending projections from the GI/ DI to the lower brainstem. After injections of an anterograde tracer, biotinylated dextranamine (BDA), into the rostral GI/ DI, many BDA-labeled axons and terminals were seen bilaterally with a contralateral predominance in the medial part of laminae I/II of Vc, dorsomedial Vo, juxtatrigeminal region, rostral ventromedial medulla (RVM), and nucleus of the solitary tract, and with an ipsilateral predominance in the parabrachial nucleus (Pb), Kö lliker-Fuse nucleus (KF) and trigeminal mesencephalic nucleus. After BDA injections into the caudal GI/DI, they were seen bilaterally with a contralateral predominance in the lateral part of laminae I/II of Vc, ventrolateral Vo, juxtatrigeminal region and RVM, and with an ipsilateral dominance in the lateral zone (PAGl) of periaqueductal gray, Pb and KF. These results suggest that orofacial nociceptive processing of Vc and Vo neurons may be regulated by GI/DI directly or indirectly through brainstem nuclei such as PAGl, Pb, KF and RVM.
The roles of supramedullary brain mechanisms involved in the control of jaw movements are not ful... more The roles of supramedullary brain mechanisms involved in the control of jaw movements are not fully understood. To address this issue, a series of retrograde (Fluorogold, FG) and anterograde (biotinylated dextran amine, BDA) tract-tracing studies were done in rats. At first, we identified projection patterns from defined sensorimotor cortical areas to subgroups of trigeminal premotoneurons that are located in defined brainstem areas. Focal injections of FG into these brainstem areas revealed that the rostralmost part of lateral agranular cortex (rmost-Agl), the rostralmost part of medial agranular cortex (rmost-Agm), and the rostralmost
Study Objectives: Sleep bruxism (SB) is reported to vary in frequency over time. The aim of this ... more Study Objectives: Sleep bruxism (SB) is reported to vary in frequency over time. The aim of this study was to assess the fi rst night effect on SB. Methods: A retrospective polysomnographic (PSG) analysis was performed of data from a sample of SB patients (12 females, 4 males; age range: 17-39 years) recorded in a sleep laboratory over 2 consecutive nights. Sleep parameters and jaw muscle activity variables (i.e., rhythmic masticatory muscle activity [RMMA]) for SB were quantifi ed and compared between the 2 nights. Subjects were classifi ed into groups according to severity of RMMA frequency, such as low frequency (2-4 episodes/h and/or < 25 bursts/h) and moderatehigh frequency (≥ 4 episodes/h and ≥ 25 bursts/h). Results: Overall, no fi rst night effects were found for most sleep variables. However, total sleep time, sleep effi ciency, and stage transitions showed signifi cant time and group interactions (repeated measures ANOVAs, p ≤ 0.05). The RMMA episode index did not differ between the 2 nights, whereas the second night showed signifi cantly higher burst index, bruxism time index, and mean burst duration (repeated measure ANOVAs, p ≤ 0.05). Five patients of 8 in the low frequency group were classifi ed into the moderate-high frequency group on the second night, whereas only one patient in the moderate-high frequency group moved to the low frequency group. Conclusions: The results showed no overall fi rst night effect on severity of RMMA frequency in young and healthy patients with SB. In clinical practice, one-night sleep recording may be suffi cient for moderate-high frequency SB patients. However, low RMMA frequency in the fi rst night could be confi rmed by a second night based on the patient's medical and dental history.
Sleep bruxism (SB) is an unusual orofacial movement described as a parafunction in dentistry and ... more Sleep bruxism (SB) is an unusual orofacial movement described as a parafunction in dentistry and as a parasomnia in sleep medicine. Since several peripheral influences could be involved in sleep-wake regulation and the genesis of rhythmic jaw movements, the authors have reviewed the relevant literature to facilitate understanding of mechanisms possibly involved in SB genesis. Various animal and human studies indicate that during either wakefulness or anesthesia, orofacial sensory inputs (e.g., from periodontium, mucosa, and muscle) could influence jaw muscle activity. However, the role of these sensory inputs in jaw motor activity during sleep is unclear. Interestingly, during sleep, the jaw is usually open due to motor suppression; tooth contact most likely occurs in association with sleep arousal. Recent physiologic evidence supports an association between sleep arousal and SB; a sequential change from autonomic (cardiac) and brain cortical activities precede SB-related jaw motor ...
Sleep bruxism is a sleep-related movement disorder characterized by an exaggerated jaw motor acti... more Sleep bruxism is a sleep-related movement disorder characterized by an exaggerated jaw motor activity during sleep. Currently, the magnitude of jaw motor activation in normal sleep remains poorly understood. In this study, we aim to assess the state-dependent changes in the magnitude of electromyographic activities of the jaw-closing masseter muscle in comparison with those of a neck muscle (specifically, the obliquus capitis) during sleep-wake cycles in guinea pigs. These electromyographic activities were integrated for 10-s epochs during wakefulness, non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. The masseter activity per epoch was found to be five times lower in both sleep stages while the neck muscle activity also decreased to 30% in NREM sleep and was lowest (16%) in REM sleep. In the periods without motor activity, masseter tone did not differ between the three states, whereas neck muscle tone decreased from wakefulness to NREM sleep and further to REM sleep. Moreover, in the epochs with masseter activation, the neck muscle activity did not increase during sleep. These results suggest that masseter activity decreases but is occasionally activated during sleep, and that state-dependent changes in electromyographic activity can be differently modulated in time and intensity between the masseter and the obliquus capitis.
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