Swallowing Preparation and Execution: Insights from a Delayed-Response Functional Magnetic Resonance Imaging (fMRI) Study.

The present study sought to elucidate the functional contributions of sub-regions of the swallowing neural network in swallowing preparation and swallowing motor execution. Seven healthy volunteers participated in a delayed-response, go, no-go functional magnetic resonance imaging study involving four semi-randomly ordered activation tasks: (i) "prepare to swallow," (ii) "voluntary saliva swallow," (iii) "do not prepare to swallow," and (iv) "do not swallow." Results indicated that brain activation was significantly greater during swallowing preparation, than during swallowing execution, within the rostral and intermediate anterior cingulate cortex bilaterally, premotor cortex (left > right hemisphere), pericentral cortex (left > right hemisphere), and within several subcortical nuclei including the bilateral thalamus, caudate, and putamen. In contrast, activation within the bilateral insula and the left dorsolateral pericentral cortex was significantly greater in relation to swallowing execution, compared with swallowing preparation. Still other regions, including a more inferior ventrolateral pericentral area, and adjoining Brodmann area 43 bilaterally, and the supplementary motor area, were activated in relation to both swallowing preparation and execution. These findings support the view that the preparation, and subsequent execution, of swallowing are mediated by a cascading pattern of activity within the sub-regions of the bilateral swallowing neural network.

A systematic review and meta-analysis examining pneumonia-associated mortality in dementia.

BACKGROUND: Although it is generally accepted that deaths associated with pneumonia are more common in patients with dementia, no comprehensive reviews on the subject have previously been published. SUMMARY: Relevant studies were identified through a literature search of the PubMed, EMBASE, Scopus, and ISI Web of Science databases for publications up to August 2013. Studies were included if (1) a group of adult subjects with dementia and a (comparison) group composed of subjects without dementia were included, (2) the cause(s) of death was/were reported, and (3) pneumonia was identified as one of the possible causes of death. The occurrence of death due to pneumonia associated with dementia was expressed as an odds ratio (OR) with 95% confidence interval (CI). Thirteen studies were included. The odds of death resulting from pneumonia were significantly increased for persons with any form of dementia compared with those without dementia (OR = 2.22, 95% CI 1.44-3.42, p < 0.001). In a subgroup analysis, using the results from 8 studies that restricted inclusion to persons with Alzheimer's disease, the odds of death resulting from pneumonia were also significantly higher (OR = 1.70, 95% CI 1.12-2.58, p = 0.013). Key Messages: The odds of pneumonia-associated mortality were increased more than 2-fold for patients with dementia.

Occurrences of yawn and swallow are temporally related.

Yawning is a stereotyped motor behavior characterized by deep inhalation and associated dilation of the respiratory tract, pronounced jaw opening, and facial grimacing. The frequency of spontaneous yawning varies over the diurnal cycle, peaking after waking and before sleep. Yawning can also be elicited by seeing or hearing another yawn, or by thinking about yawning, a phenomenon known as "contagious yawning". Yawning is mediated by a distributed network of brainstem and supratentorial brain regions, the components of which are shared with other airway behaviors including respiration, swallowing, and mastication. Nevertheless, the possibility of behavioral coordination between yawning and other brainstem-mediated functions has not been examined. Here we show, with a double-blind methodology, a greater-than-fivefold increase in rest (saliva) swallowing rate during the 10-s period immediately following contagious yawning elicited in 14 adult humans through the viewing of videotaped yawn stimuli. Sixty-five percent of yawns were followed by a swallow within 10 s and swallows accounted for 26 % of all behaviors produced during this post-yawn period. This novel finding of a tight temporal coupling between yawning and swallowing provides preliminary evidence that yawning and swallowing are physiologically related, thus extending current models of upper airway physiology and neurophysiology. Moreover, our finding suggests the possibility that yawning plays a role in eliciting rest swallowing, a view not considered in previous theories of yawning. As such, the present demonstration of a temporal association between yawning and swallowing motivates a re-examination of the longstanding question, "Why do we yawn?".

Evidence of Decreased Long-term Risk of Cervical Precancer after Negative Primary HPV Screens Compared with Negative Cytology Screens in a Longitudinal Cohort Study.

BACKGROUND: The growing use of primary human papillomavirus (HPV) cervical cancer screening requires determining appropriate screening intervals to avoid overtreatment of transient disease. This study examined the long-term risk of cervical precancer after HPV screening to inform screening interval recommendations. METHODS: This longitudinal cohort study (British Columbia, Canada, 2008 to 2022) recruited women and individuals with a cervix who received 1 to 2 negative HPV screens (HPV1 cohort, N = 5,546; HPV2 cohort, N = 6,624) during a randomized trial and women and individuals with a cervix with 1 to 2 normal cytology results (BCS1 cohort, N = 782,297; BCS2 cohort, N = 673,778) extracted from the provincial screening registry. All participants were followed through the registry for 14 years. Long-term risk of cervical precancer or worse [cervical intraepithelial neoplasia grade 2 or worse (CIN2+)] was compared between HPV and cytology cohorts. RESULTS: Cumulative risks of CIN2+ were 3.2/1,000 [95% confidence interval (CI), 1.6-4.7] in HPV1 and 2.7/1,000 (95% CI, 1.2-4.2) in HPV2 after 8 years. This was comparable with the risk in the cytology cohorts after 3 years [BCS1: 3.3/1,000 (95% CI, 3.1-3.4); BCS2: 2.5/1,000 (95% CI, 2.4-2.6)]. The cumulative risk of CIN2+ after 10 years was low in the HPV cohorts [HPV1: 4.7/1,000 (95% CI, 2.6-6.7); HPV2: 3.9 (95% CI, 1.1-6.6)]. CONCLUSIONS: Risk of CIN2+ 8 years after a negative screen in the HPV cohorts was comparable with risk after 3 years in the cytology cohorts (the benchmark for acceptable risk). IMPACT: These findings suggest that primary HPV screening intervals could be extended beyond the current 5-year recommendation, potentially reducing barriers to screening.

Proof-of-principle pilot study of oropharyngeal air-pulse application in individuals with dysphagia after hemispheric stroke.

OBJECTIVE: To test the hypothesis that oropharyngeal air-pulse application is associated with increased swallowing rates in individuals with dysphagia secondary to stroke. DESIGN: Case control. SETTING: Stroke rehabilitation hospital or home setting. PARTICIPANTS: Convenience sample of individuals (N=8) with new-onset dysphagia after stroke. INTERVENTIONS: Air-pulse trains were applied to the oropharynx of 8 subjects who presented with dysphagia after hemispheric stroke. Resting swallowing rates were determined for 5 experimental conditions: baseline without air-pulse mouthpiece, baseline with mouthpiece in situ, unilateral right oropharyngeal air-pulse, unilateral left oropharyngeal air-pulse, and bilateral oropharyngeal air-pulse application. Individual swallowing responses were analyzed using a 2-SD band method. MAIN OUTCOME MEASURE: Swallowing rate (swallows/min). RESULTS: Swallowing rates associated with bilateral air-pulse application were greater than baseline in 4 of the 8 subjects. The 4 subjects who demonstrated this response to air-pulse application had greater baseline swallowing rates than did subjects whose swallowing rates were not altered in association with air-pulse application. CONCLUSIONS: Oropharyngeal air-pulse trains can be applied in individuals with swallowing impairment. Air-pulse application is associated with increased resting swallowing rates in some individuals with dysphagia secondary to hemispheric stroke. Further research should extend this proof-of-principle study by examining the efficacy of oropharyngeal air-pulse application in terms of improved swallowing and related outcomes in dysphagic stroke through a large randomized trial.

The Development of Nutritional Supplement Fact Sheets for Irish Athletes: A Case Study.

The use of sports supplements presents a dilemma for many of those involved in supporting athletes, including coaches, families, support staff and the athletes themselves. Often the information that they source can be incorrect and promote a bias view regarding the use of nutritional supplements. The aim of this case study was to describe the process that occurred around the development of a series of targeted educational factsheets on a range of nutritional supplements for Irish athletes. It describes the initiation and support of the process by the Irish Sports Council, one of its subgroups, The Food and Food Supplements Committee, and the Irish Institute of Sport. A needs assessment through questionnaires was carried out to establish the most commonly used sports nutrition supplements by athletes, aged sixteen or over in Ireland. One hundred and five questionnaires were completed over a 4-month period in 2008-2009 that lead to the production of 20 supplement fact sheets. These supplement fact sheets will enable Irish athletes to access high quality, up to date, scientific information regarding the supplements they have reported consuming. Since personal reading had a strong influence over the athlete's decision-making process for taking nutritional supplements, as did scientific research, fact sheets available on the internet from a reliable source is an ideal way to educate Irish athletes.

The development of nutritional-supplement fact sheets for Irish athletes: a case study.

The use of sport supplements presents a dilemma for many of those involved in supporting athletes, including coaches, families, support staff, and the athletes themselves. Often the information that they source can be incorrect and promote a biased view regarding the use of nutritional supplements. The aim of this case study was to describe the process that occurred around the development of a series of targeted educational fact sheets on a range of nutritional supplements for Irish athletes. It describes the initiation and support of the process by the Irish Sports Council; one of its subgroups, the Food and Food Supplements Committee; and the Irish Institute of Sport. A needs assessment through questionnaires was carried out to establish the most commonly used sport nutrition supplements by athletes age 16 or over in Ireland. Respondents completed 105 questionnaires over a 4-mo period in 2008-09 that led to the production of 20 supplement fact sheets. These supplement fact sheets will enable Irish athletes to access high-quality, up-to-date, scientific information about the supplements they have reported consuming. Since personal reading had a strong influence over athletes' decision-making process for taking nutritional supplements, as did scientific research, fact sheets available on the Internet from a reliable source are an ideal way to educate Irish athletes.

Stuttered swallowing: electric stimulation of the right insula interferes with water swallowing. A case report.

BACKGROUND: Various functional resonance imaging, magnetoencephalographic and lesion studies suggest the involvement of the insular cortex in the control of swallowing. However, the exact location of insular activation during swallowing and its functional significance remain unclear. CASE PRESENTATION: Invasive electroencephalographic monitoring was performed in a 24-year-old man with medically intractable stereotyped nocturnal hypermotor seizures due to a ganglioglioma. During stimulation of the right inferior posterior insular cortex with depth electrodes the patient spontaneously reported a perception of a "stutter in swallowing". Stimulation of the inferior posterior insular cortex at highest intensity (4 mA) was also associated with irregular and delayed swallows. Swallowing was not impaired during stimulation of the superior posterior insular cortex, regardless of stimulation intensity. CONCLUSIONS: These results indicate that the right inferior posterior insular cortex is involved in the neural circuitry underlying the control of swallowing.

Assessing 10-Year Safety of a Single Negative HPV Test for Cervical Cancer Screening: Evidence from FOCAL-DECADE Cohort.

BACKGROUND: Long-term safety of a single negative human papillomavirus (HPV) test for cervical cancer screening is unclear. The HPV FOr cerviCAL Cancer Trial (FOCAL) was a randomized trial comparing HPV testing with cytology. The FOCAL-DECADE cohort tracked women who received one HPV test during FOCAL, and were HPV negative, for up to 10 years to identify cervical intraepithelial neoplasia grade 2 or worse (CIN2+) and grade 3 or worse (CIN3+) detected through a provincial screening program. METHODS: FOCAL participants who received one HPV test, were negative, and had at least one post-FOCAL cervix screen were included (N = 5,537). We constructed cumulative incidence curves of CIN2+/CIN3+ detection, analyzed cumulative risk of detection at intervals post-HPV test, calculated average incidence rates for detection, and compared hazard across ages. RESULTS: Ten years after one negative HPV test, the probability of CIN2+ detection was lower than 1%, with most lesions detected 7 years or later. Average incidence rates of CIN2+/CIN3+ lesions over follow-up were 0.50 [95% confidence interval (CI), 0.31-0.78] and 0.18 (95% CI, 0.07-0.36) per 1,000 person-years, respectively. Hazards were higher for younger ages (nonsignificant trend). CONCLUSIONS: Among women with a single negative HPV test, long-term risk of CIN2+ detection was low, particularly through 7 years of follow-up; thus, one negative HPV test appears to confer long-term protection from precancerous lesions. Even 10-year risk is sufficiently low to support extended testing intervals in average-risk populations. IMPACT: Our findings support the safety of screening policies using HPV testing alone at 5-year or longer intervals.

Risk of overdose-related death for people with a history of incarceration.

BACKGROUND AND AIMS: Reported associations between previous incarceration and the risk of overdose-related death are substantially heterogeneous, and previous studies are limited by an inability to control for confounding factors in risk assessment. This study investigated the associations of overdose-related death with previous incarceration and the number or cumulative duration of previous incarcerations, and individual or neighborhood characteristics that may potentially modify the associations. DESIGN AND SETTING: A cohort study using a 20% random sample of residents in British Columbia, Canada. PARTICIPANTS: A total of 765 690 people aged 23 years or older at baseline as of 1 January 2015. Mean age was 50 years; 49% were males. MEASUREMENTS: Previous incarcerations that occurred during the 5-year exposure period (January 2010 to December 2014) were identified using provincial incarceration records. Overdose-related deaths that occurred during the 3-year follow-up period (January 2015 to December 2017) were identified using linked administrative health data. Baseline individual and neighborhood characteristics were retrieved from the provincial health insurance data. FINDINGS: In the cohort, 5743 people had an incarceration history during the exposure period, and 634 people died from drug overdose during the follow-up period. The mortality rate was 897 and 22 per 100 000 person-years for people who did and did not have an incarceration history, respectively. After adjusting for baseline individual and neighborhood characteristics (without any interaction term), people who had an incarceration history were 4.04 times (95% confidence interval 3.23-5.06) more likely to die from drug overdose compared with people without an incarceration history. The association was stronger for females, people without diagnoses of substance use disorder and people without dispensation of opioids for pain or benzodiazepines (P < 0.001 for each interaction term). There was no discernible linear trend between the number or cumulative duration of previous incarcerations and the risk of overdose-related death. CONCLUSIONS: Previous incarceration appears to be a major risk factor for overdose-related death.

A randomized controlled trial of Human Papillomavirus (HPV) testing for cervical cancer screening: trial design and preliminary results (HPV FOCAL Trial).

BACKGROUND: In the HPV FOCAL trial, we will establish the efficacy of hr-HPV DNA testing as a stand-alone screening test followed by liquid based cytology (LBC) triage of hr-HPV-positive women compared to LBC followed by hr-HPV triage with > or = CIN3 as the outcome. METHODS/DESIGN: HPV-FOCAL is a randomized, controlled, three-armed study over a four year period conducted in British Columbia. It will recruit 33,000 women aged 25-65 through the province's population based cervical cancer screening program. Control arm: LBC at entry and two years, and combined LBC and hr-HPV at four years among those with initial negative results and hr-HPV triage of ASCUS cases; Two Year Safety Check arm: hr-HPV at entry and LBC at two years in those with initial negative results with LBC triage of hr-HPV positives; Four Year Intervention Arm: hr-HPV at entry and combined hr-HPV and LBC at four years among those with initial negative results with LBC triage of hr-HPV positive cases DISCUSSION: To date, 6150 participants have a completed sample and epidemiologic questionnaire. Of the 2019 women enrolled in the control arm, 1908 (94.5%) were cytology negative. Women aged 25-29 had the highest rates of HSIL (1.4%). In the safety arm 92.2% of women were hr-HPV negative, with the highest rate of hr-HPV positivity found in 25-29 year old women (23.5%). Similar results were obtained in the intervention arm HPV FOCAL is the first randomized trial in North America to examine hr-HPV testing as the primary screen for cervical cancer within a population-based cervical cancer screening program. TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number Register, ISRCTN79347302.

Functional brain imaging of swallowing: an activation likelihood estimation meta-analysis.

A quantitative, voxel-wise meta-analysis was performed to investigate the cortical control of water and saliva swallowing. Studies that were included in the meta-analysis (1) examined water swallowing, saliva swallowing, or both, and (2) reported brain activation as coordinates in standard space. Using these criteria, a systematic literature search identified seven studies that examined water swallowing and five studies of saliva swallowing. An activation likelihood estimation (ALE) meta-analysis of these studies was performed with GingerALE. For water swallowing, clusters with high activation likelihood were found in the bilateral sensorimotor cortex, right inferior parietal lobule, and right anterior insula. For saliva swallowing, clusters with high activation likelihood were found in the left sensorimotor cortex, right motor cortex, and bilateral cingulate gyrus. A between-condition meta-analysis revealed clusters with higher activation likelihood for water than for saliva swallowing in the right inferior parietal lobule, right postcentral gyrus, and right anterior insula. Clusters with higher activation likelihood for saliva than for water swallowing were found in the bilateral supplementary motor area, bilateral anterior cingulate gyrus, and bilateral precentral gyrus. This meta-analysis emphasizes the distributed and partly overlapping cortical networks involved in the control of water and saliva swallowing. Water swallowing is associated with right inferior parietal activation, likely reflecting the sensory processing of intraoral water stimulation. Saliva swallowing more strongly involves premotor areas, which are crucial for the initiation and control of movements.

Neuroplasticity and swallowing.

Recent research has suggested that the central nervous system controlling swallowing can undergo experience-dependent plasticity. Moreover, swallowing neuroplastic change may be associated with behavioural modulation. This article presents research evidence suggesting that nonbehavioural and behavioural interventions, as well as injury, can induce swallowing neuroplasticity. These studies indicate that while swallowing and limb neuroplasticity share certain features, certain principles of swallowing neuroplasticity may be distinct. Thus, an understanding of swallowing neuroplasticity is necessary in terms of explaining and predicting the (1) behavioural effects of injury to the swallowing nervous system and (2) effects of swallowing interventions applied in rehabilitation.

Differentiating effortful and noneffortful swallowing with a neck force transducer: implications for the development of a clinical feedback system.

This study sought to determine whether effortful saliva swallows could be differentiated from habitual, noneffortful saliva swallows on the basis of swallow-related changes in neck circumference in humans. Gender differences in swallow-related neck circumference were examined as a secondary question. Twenty-seven healthy adults (14 females; mean age = 26.6 years, SD = 3.9 years) participated in two experimental runs (run duration = 10 min) during which they produced single trials of three visually cued tasks in random order: effortful saliva swallowing, saliva swallowing, and a control task involving repetitive apposition of the dominant thumb and index finger. Neck and ribcage circumference were simultaneously collected from the output of force transducers positioned around the neck and ribcage, respectively. The primary outcome variables were the positive and negative voltage peak amplitudes associated with changes in neck circumference during single-swallow trials. Effects of the swallowing task on positive and negative voltage peaks were examined with separate two-way analysis of variance procedures. Results indicated that both positive (F = 6.49, p < 0.05) and negative (F = 12.05, p

Effects of oropharyngeal air-pulse stimulation on swallowing in healthy older adults.

While previous research has shown that air-pulse stimulation of the oropharynx facilitates saliva swallowing in young adults, the effects of air pulses in older adults have not been examined. Responses to air-pulse stimulation may differ in young and older adults given age-related changes in sensation, swallowing physiology, and swallow-related brain activation. Therefore, this study sought to determine the effects of oropharyngeal air-pulse stimulation on saliva swallowing rates in 18 healthy older adults. Saliva swallowing rates were monitored across six conditions: baseline without mouthpiece, baseline with mouthpiece in situ, unilateral right oropharyngeal stimulation, unilateral left oropharyngeal stimulation, bilateral oropharyngeal stimulation, and sham stimulation. Results indicated that bilateral oropharyngeal air-pulse stimulation was associated with a statistically significant increase in mean saliva swallowing rate compared to baseline without mouthpiece, baseline with mouthpiece in situ, and sham stimulation. In previous studies, young adults reported an irrepressible urge to swallow in response to oropharyngeal air-pulse delivery, but the older adults in the current study did not perceive the air-pulse stimulation as being associated with swallowing or other behaviors. These findings indicate that oropharyngeal air-pulse stimulation facilitates the elicitation of saliva swallowing in older adults.

Women, incarceration and HIV: a systematic review of HIV treatment access, continuity of care and health outcomes across incarceration trajectories.

OBJECTIVE: The aim of this study was to systematically review the literature on gendered implications of incarceration for HIV outcomes and engagement in care for women living with HIV (WLWH). DESIGN: We systematically searched seven bibliographic databases, for peer-reviewed English-language studies, published between 2007 and 2017 reporting on incarceration, women (transgender inclusive) and HIV. METHODS: Articles were included for evaluation if they reported outcomes for at least one of three measures of interest: viral load, antiretroviral therapy (ART) adherence or engagement in care among WLWH along incarceration trajectories. RESULTS: Out of 1119 studies, 24 (2%) met the inclusion criteria. Of these 24 studies, the majority (n = 23) were conducted in the USA, 19 included samples of women and men and seven studies were transgender inclusive. Our review did not reveal clear sex differences in HIV outcomes during periods of incarceration; however, studies reporting postincarceration outcomes demonstrated significant sex disparities in all three outcomes of interest. Following incarceration, women were less likely to be virally suppressed, less likely to achieve optimal ART adherence and less likely to be engaged in care. CONCLUSION: Despite growing numbers of incarcerated WLWH globally, there is a substantial gap in research examining the impact of incarceration on HIV outcomes for WLWH. Significant sex disparities in HIV outcomes and engagement in care exist along incarceration trajectories for WLWH, especially postincarceration. For improved health outcomes, research is needed to examine the experiences of WLWH throughout incarceration trajectories to develop interventions tailored to the specific needs of WLWH both during and following incarceration.

Meta-Analysis of Salivary Flow Rates in Young and Older Adults.

OBJECTIVES: To determine whether salivary flow decreases as a function of aging. DESIGN: Meta-analysis. SETTING: Literature review. PARTICIPANTS: Individuals aged 18 and older reported to be free of major systemic disease. MEASUREMENTS: Relevant studies were identified through a literature search of several databases, from their inception to June 2013. Studies were included if saliva had been collected on at least one occasion in subjects aged 18 and older and if the data were presented in a manner that enabled comparisons of younger and older participants. Differences in salivary flow rates between age groups were calculated for each salivary source and condition and reported as standardized mean differences (SMDs), standard errors (SEs) and 95% confidence intervals (CIs). The results were pooled using a random effects model. A separate analysis examining medication use was also conducted. RESULTS: Forty-seven studies were included. Whole (SMD = 0.551, SE = 0.056, 95% CI = 0.423-0.678, P < .001) and submandibular and sublingual (SMSL) (SMD = 0.582, SE = 0.123, 95% CI = 0.341-0.823, P < .001) salivary flow rates were reduced significantly in older participants and in unstimulated and stimulated conditions. In contrast, parotid and minor gland salivary flow rates were not significantly reduced with increasing age. Additionally, unstimulated and stimulated SMSL, and unstimulated whole salivary flow rates were significantly lower in older adults, regardless of medication usage. CONCLUSION: The aging process is associated with reduced salivary flow in a salivary-gland-specific manner; this reduction in salivary flow cannot be explained on the basis of medications. These findings have important clinical implications for maintaining optimal oral health in older adults.

Effects of reversible bilateral inactivation of face primary motor cortex on mastication and swallowing.

The effects of reversible cold block-induced bilateral inactivation of the face primary motor cortex (face MI) on mastication and swallowing were studied in awake monkeys. A warm or cold alcohol-water solution was pumped through thermodes placed bilaterally on the dura overlying the intracortical microstimulation-defined face MI while the monkey chewed and swallowed food during pre-cool (thermode temperature 37 degrees C), cold block (4 degrees C), and post-cool (37 degrees C) sessions. Vertical and horizontal jaw movements and electromyographic (EMG) activity of several muscles were monitored. Each masticatory sequence was divided into three masticatory phases (i.e. food preparatory, rhythmic chewing, preswallow). The cold block markedly affected the ability of the monkey to carry out mastication although it did not prevent mastication from occurring. The masticatory deficit was characterized by a significant elongation of the total masticatory time, including in particular elongation of the food preparatory phase. The coordination of the jaw- and tongue-muscle activities was severely disrupted during the food preparatory phase. Face MI cold block also significantly affected the duration of some masticatory-related EMG activities and had some limited effects on the temporal relationships of the EMG activities during mastication. Although cold block significantly affected the duration and some EMG parameters of the preswallow phase, it had no significant effect on swallow duration or the EMG parameters during swallowing. These findings provide further evidence that the primate face MI plays a critical role in the regulation of mastication and that it plays a role in the preparation for swallowing.

Effects on mastication of reversible bilateral inactivation of the lateral pericentral cortex in the monkey (Macaca fascicularis).

It is known that intracortical microstimulation (ICMS) of the lateral pericentral cortex can evoke masticatory movements and swallowing in awake monkeys. The aim was to determine if the ability of monkeys to carry out mastication is affected by reversible bilateral cold block of the ICMS-defined cortical masticatory area/swallow cortex. A cranial chamber was implanted bilaterally in two monkeys and a warm or cold alcohol-water solution was pumped through thermodes placed bilaterally on the dura overlying the ICMS-defined cortical masticatory area/swallow cortex while monkeys chewed standardised amounts of fruit during pre-cool (thermode temperature, 37 degrees C), cool (0-4 degrees C), and post-cool (37 degrees C) trials. Electromyographic (EMG) activity was recorded from masseter, genioglossus, anterior digastric, geniohyoid and thyrohyoid or perilaryngeal muscles. Vertical and horizontal jaw movements were recorded with a photodiode position transducer, which monitored movements of a light-emitting diode fixed to the mandible. Each masticatory period was divided into a food-preparatory phase, a rhythmic chewing phase and a preswallow phase. Both monkeys could readily accept and ingest the foodstuffs during pre-cool and post-cool trials. In contrast, cold block was associated with masticatory deficits, reflected in both monkeys as impaired food intake or manipulation and difficulty in carrying out a sequence of masticatory cycles, alterations in of the food-preparatory phase, and alterations in masticatory-related EMG patterns of the jaw and tongue muscles. The cold block-induced changes included significant (P<0.05) prolongations of the total masticatory time, the food-preparatory phase duration, and burst durations of the jaw and tongue muscle EMG activities; furthermore, the amplitudes and temporal correlations of the EMG activities of the jaw and tongue muscles were significantly (P<0.05) changed by cold block. These findings provide further evidence that the lateral pericentral cortex has a critical role in the initiation and regulation of masticatory movements in the primate, and that the programming of masticatory muscle activities may be dependent upon corticofugal influences for engaging masticatory motor activities appropriate to the masticatory conditions.