Relationship of depth of invasion to survival outcomes and patterns of recurrence for T3 oral tongue squamous cell carcinoma.

INTRODUCTION: Current research is elucidating how the addition of depth of invasion (DOI) to the 8th edition of the American Joint Committee on Cancer (AJCC) TNM staging for oral cavity squamous cell carcinoma influences its prognostic accuracy. However, there is limited research on survival in pT3N0M0 oral tongue SCC (OTSCC) patients when stratifying by DOI. OBJECTIVES: Determine 5-year overall survival (OS), and cancer-specific survival (CSS) for patients with pT3N0M0 oral OTSCC based on shallow DOI (<10 mm) and deep DOI (10-20 mm). METHODS: Retrospective review involving three tertiary care cancer centers in North America. cT3N0M0 OTSCC patients receiving primary surgical treatment from 2004 to 2018 were identified. Inclusion: age > 18 years old and confirmation of pT3N0M0 OTSCC on surgical pathology. Exclusion: patients undergoing palliative treatment or previous head and neck surgery/radiotherapy. Analysis comprised two groups: shallow pT3 (tumor diameter > 4 cm, DOI < 10 mm) and deep pT3 (DOI 10 mm-20 mm). RESULTS: One hundred and four patients with pT3N0M0 OTSCC were included. Mean age was 59.1 years (range: 18-80.74). Age, gender, and Charlson Comorbidity Index were similar between the two groups (p > 0.05). Recurrence, LVI, PNI, and positive margins were more common in deep T3 tumors (P < 0.05). 5-year OS (50% vs 26%, p = 0.006) and CSS (72% vs 24%, p = 0.005) were worse in deep pT3 tumors. Deep pT3 disease was an independent predictor of OS (p = 0.004) and CSS (p = 0.01) on Cox-Regression analysis. CONCLUSION: DOI is an independent predictor of poor survival in pT3N0M0 OTSCC patients. Consideration should be given to escalating adjuvant therapy for deep pT3N0M0 OTSCC patients.

A new MMPI-derived indicator of liability to develop schizophrenia: evidence from the New York High-Risk Project.

A large body of research indicates that the liability to develop schizophrenia is largely genetically mediated, although phenotypic expression requires environmental triggers/insults and/or epigenetic and/or stochastic factors. In an effort to identify the precise environmental factors that precipitate a predisposition to schizophrenia, researchers have implemented a high-risk model-the prospective study of offspring born to schizophrenic parents. As it is difficult to ascertain exactly which of the "high-risk" participants will actually develop the disorder, we examined the validity of an experimental MMPI scale, Schizophrenia Proneness (SzP), and the Moldin-Gottesman psychometric index to identify such individuals. Results suggest that the SzP scale can be an effective predictor of schizophrenia-related psychoses. A revised psychometric index is offered for further study.

Functional MRI evidence of cortical reorganization in upper-limb stroke hemiplegia treated with constraint-induced movement therapy.

OBJECTIVE: The purpose of this pilot study was to test constraint-induced movement therapy for chronic upper-limb stroke hemiparesis and to investigate the neural correlates of recovery with functional magnetic resonance imaging (MRI) in two subjects. Both subjects had been discharged from traditional therapy because no further improvement was anticipated. DESIGN: Constraint-induced movement therapy consisted of 6 hr of daily upper-limb training for 2 wk; a restrictive mitt was worn on the nonparetic limb during waking hours. Functional MRI was performed on a 1.5-T MRI with echo-planar imaging; at the same time, the subjects attempted sequential finger-tapping. RESULTS: Compared with baseline, performance time improved an average of 24% immediately after training and also continued to improve up to 33% 3 mo after training. Lift, grip strength, and Motor Activity Log scores likewise improved. Initially, on functional MRI, subject 1 activated scattered regions in the ipsilateral posterior parietal and occipital cortices. Subject 2 showed almost no areas of significant activation. After training, subject 1 showed activity bordering the lesion, bilateral activation in the association motor cortices, and ipsilateral activation in the primary motor cortex. Subject 2 showed activation near the lesion site. CONCLUSION: Constraint-induced movement therapy produced significant functional improvement and resulted in plasticity as demonstrated by functional MRI.

Effect of temperature and salinity stress on growth and lipid composition of Shewanella gelidimarina.

The maximum growth temperature, the optimal growth temperature, and the estimated normal physiological range for growth of Shewanella gelidimarina are functions of water activity (a(w)), which can be manipulated by changing the concentration of sodium chloride. The growth temperatures at the boundaries of the normal physiological range for growth were characterized by increased variability in fatty acid composition. Under hyper- and hypoosmotic stress conditions at an a(w) of 0.993 (1.0% [wt/vol] NaCl) and at an a(w) of 0.977 (4.0% [wt/vol] NaCl) the proportion of certain fatty acids (monounsaturated and branched-chain fatty acids) was highly regulated and was inversely related to the growth rate over the entire temperature range. The physical states of lipids extracted from samples grown at stressful a(w) values at the boundaries of the normal physiological range exhibited no abrupt gel-liquid phase transitions when the lipids were analyzed as liposomes. Lipid packing and adaptational fatty acid composition responses are clearly influenced by differences in the temperature-salinity regime, which are reflected in overall cell function characteristics, such as the growth rate and the normal physiological range for growth.

Physicochemical parameters for growth of the sea ice bacteria Glaciecola punicea ACAM 611(T) and Gelidibacter sp. strain IC158.

The water activity and pH ranges for growth of Glaciecola punicea (a psychrophile) were extended when this organism was grown at suboptimal rather than optimal temperatures. No such extension was observed for Gelidibacter sp. strain IC158 (a psychrotolerant bacterium) at analogous temperatures. Salinity and pH may be primary physicochemical parameters controlling bacterial community development in sea ice.

Childhood imbalance and chronic otitis media with effusion: effect of tympanostomy tube insertion on standardized tests of balance and locomotion.

The goal of this study was to investigate the role of chronic otitis media with effusion as a cause of childhood imbalance. Nineteen 4- to 6-year-old children with chronic otitis media with effusion and 14 matched control children underwent a series of laboratory tests, including two standardized tests of balance and locomotion: the Peabody Developmental Motor Scales (PDMS) and the Bruininks-Oseretsky Test of Motor Proficiency (BOTMP). The children in the chronic otitis media with effusion group underwent tympanostomy tube insertion. Both groups underwent the same battery of tests within 6 to 8 weeks of initial testing. Analysis of variance for the PDMS and BOTMP demonstrated significantly lower performance in the balance subscales for the otitis group before (P < .01). Both otitis and control groups improved when retested. The improvement was greater and approaching significance in the otitis group on the PDMS and BOTMP (P = .056 and .097, respectively). It is concluded that chronic otitis media with effusion significantly affects balance and coordination skills in 4- to 6-year-old children. These skills improve after tympanostomy tube insertion at a rate greater than that of the control group.

Comparison of upper-extremity balance tasks and force platform testing in persons with hemiparesis.

BACKGROUND AND PURPOSE: The purpose of this study was to investigate the relationship between clinically accessible functional balance tools and sophisticated force platform measures in a standing position. SUBJECTS: Twenty persons who had hemiparesis secondary to a stroke and were ambulatory (mean age = 57.9 years, SD = 13.6, range = 35-79) were evaluated during a single testing session. METHODS: Performances on self-generated upper-extremity balance tasks using the nonparetic side (Functional Reach Test [FRT], arm raise and arm reach tasks) were compared with responses to external perturbations on the Balance System (postural sway, symmetry of weight distribution). RESULTS: No relationship was found between the upper-extremity balance tests and the force platform measures of postural sway. After suppressing the effect of age by means of partial correlation coefficients, the FRT was correlated with measures of postural symmetry in parallel stance on the Balance System (r = .66-.78). The FRT was only moderately correlated with the arm raise and arm reach tasks (r = .43 and .44). CONCLUSION AND DISCUSSION: Postural sway in response to force platform perturbations may have little relation to the postural control necessary for self-generated upper-extremity balance tasks. In contrast, the FRT and the force platform measures of postural symmetry appear to be evaluating comparable standing-balance abilities in persons with hemiparesis. The modest relationship between the FRT and the arm raise and arm reach tasks limits the finding's clinical relevance.

Quantitative microbiology: a basis for food safety.

Because microorganisms are easily dispersed, display physiologic diversity, and tolerate extreme conditions, they are ubiquitous and may contaminate and grow in many food products. The behavior of microbial populations in foods (growth, survival, or death) is determined by the properties of the food (e.g., water activity and pH) and the storage conditions (e.g., temperature, relative humidity, and atmosphere). The effect of these properties can be predicted by mathematical models derived from quantitative studies on microbial populations. Temperature abuse is a major factor contributing to foodborne disease; monitoring temperature history during food processing, distribution, and storage is a simple, effective means to reduce the incidence of food poisoning. Interpretation of temperature profiles by computer programs based on predictive models allows informed decisions on the shelf life and safety of foods. In- or on-package temperature indicators require further development to accurately predict microbial behavior. We suggest a basis for a "universal" temperature indicator. This article emphasizes the need to combine kinetic and probability approaches to modeling and suggests a method to define the bacterial growth/no growth interface. Advances in controlling foodborne pathogens depend on understanding the pathogens' physiologic responses to growth constraints, including constraints conferring increased survival capacity.

Shewanella gelidimarina sp. nov. and Shewanella frigidimarina sp. nov., novel Antarctic species with the ability to produce eicosapentaenoic acid (20:5 omega 3) and grow anaerobically by dissimilatory Fe(III) reduction.

A polyphasic taxonomic study was performed to characterize dissimilatory iron-reducing strains mostly isolated from Antarctic sea ice. The strains were isolated from samples of congelated (land-fast) sea ice, grease ice, and ice algal biomass collected from the coastal areas of the Vestfold Hills in eastern Antarctica (68 degrees S 78 degrees E). The strains were facultatively anaerobic, motile, and rod shaped, were capable of anaerobic growth either by fermentation of carbohydrates or by anaerobic respiration, and utilized a variety of electron acceptors, including nitrate, ferric compounds, and trimethylamine N-oxide. A phylogenetic analysis performed with 16S rRNA sequences showed that the isolates formed two groups representing novel lineages in the genus Shewanella. The first novel group included seawater-requiring, psychrophilic, chitinolytic strains which had DNA G + C contents of 48 mol%. The members of the second strain group were psychrotrophic and did not require seawater but could tolerate up to 9% NaCl. The strains of this group were also unable to degrade polysaccharides but could utilize a number of monosaccharides and disaccharides and had G + C contents of 40 to 43 mol%. The whole-cell-derived fatty acid profiles of the sea ice isolates were found to be similar to the profiles obtained for other Shewanella species. The omega-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA) (20:5 omega 3) was detected in all of the sea ice isolates at levels ranging from 2 to 16% of the total fatty acids. EPA was also found at high levels in Shewanella hanedai (19 to 22%) and Shewanella benthica (16 to 18%) but was absent in Shewanella alga and Shewanella putrefaciens. On the basis of polyphasic taxonomic data, the Antarctic iron-reducing strains are placed in two new species, Shewanella frigidimarina sp. nov. (type strain, ACAM 591) and Shewanella gelidimarina sp. nov. (type strain, ACAM 456).

Diversity and association of psychrophilic bacteria in Antarctic sea ice.

The bacterial populations associated with sea ice sampled from Antarctic coastal areas were investigated by use of a phenotypic approach and a phylogenetic approach based on genes encoding 16S rRNA (16S rDNA). The diversity of bacteria associated with sea ice was also compared with the bacterial diversity of seawater underlying sea ice. Psychrophilic (optimal growth temperature, < or = 15 degrees C; no growth occurring at 20 degrees C) bacterial diversity was found to be significantly enriched in sea ice samples possessing platelet and bottom ice diatom assemblages, with 2 to 9 distinct (average, 5.6 +/- 1.8) psychrophilic taxa isolated per sample. Substantially fewer psychrophilic isolates were recovered from ice cores with a low or negligible population of ice diatoms or from under-ice seawater samples (less than one distinct taxon isolated per sample). In addition, psychrophilic taxa that were isolated from under-ice seawater samples were in general phylogenetically distinct from psychrophilic taxa isolated from sea ice cores. The taxonomic distributions of psychrotrophic bacterial isolates (optimal growth temperature, > 20 degrees C; growth can occur at approximately 4 degrees C) isolated from sea ice cores and under-ice seawater were quite similar. Overall, bacterial isolates from Antarctic sea ice were found to belong to four phylogenetic groups, the alpha and gamma subdivisions of the Proteobacteria, the gram-positive branch, and the Flexibacter-Bacteroides-Cytophaga phylum. Most of the sea ice strains examined appeared to be novel taxa based on phylogenetic comparisons, with 45% of the strains being psychrophilic. 16S rDNA sequence analysis revealed that psychrophilic strains belonged to the genera Colwellia, Shewanella, Marinobacter, Planococcus, and novel phylogenetic lineages adjacent to Colwellia and Alteromonas and within the Flexibacter-Bacteroides-Cytophaga phylum. Psychrotrophic strains were found to be members of the genera Pseudoalteromonas, Psychrobacter, Halomonas, Pseudomonas, Hyphomonas, Sphingomonas, Arthrobacter, Planococcus, and Halobacillus. From this survey, it is proposed that ice diatom assemblages provide niches conducive to the proliferation of a diverse array of psychrophilic bacterial species.

Polyunsaturated fatty acids in the psychrophilic bacterium Shewanella gelidimarina ACAM 456T: molecular species analysis of major phospholipids and biosynthesis of eicosapentaenoic acid.

The production of eicosapentaenoic acid [20:5omega3; EPA] from Shewanella gelidimarina (ACAM 456T) was investigated with respect to growth temperature and growth on sole carbon sources. The percentage and quantitative yield of EPA remained relatively constant at all growth temperatures within or below the optimal growth temperature region. At higher growth temperatures, these values decreased greatly. Growth on differing sole carbon sources also influenced the percentage and amount of EPA produced, with the fatty acid composition influenced by provision of potential acyl chain primers as sole carbon sources. The highest amounts of EPA occurred from growth on propionic acid and L-leucine respectively, while the highest percentage of EPA occurred from growth on L-proline. Monounsaturated fatty acid components and EPA were concentrated in phosphatidylglycerol (PG), while the proportion of branched-chain fatty acids was elevated in phosphatidylethanolamine (PE); the two major phospholipid classes. Specific associations of EPA with other acyl chains were identified within cellular phospholipid classes. The association of EPA with 17:1 and 18:0 acyl chains in phospholipid species was specific to PG, whereas the association of EPA with i13:0/13:0 and 14:0/i14:0 was specific to PE. Such acyl chain 'tailoring' is indicative of the important role of EPA in bacterial membrane adaptive responses. EPA was also a large component (22%) of a non-esterified fatty acid (NEFA) fraction within the total lipid extract of the bacterium. This may point toward a particular role of NEFA in polyunsaturated fatty acid (PUFA) metabolism. The formation of EPA was investigated by labelling with L-[U-14C]serine and sodium [1-14C]acetate. The accumulation of radiolabel within unsaturated intermediates (di-, tri- and tetraunsaturated fractions) was low, indicating a rapid formation and derivatisation of these components. Similar results were found for the unsaturated fatty acid fractions of both PE and PG using sodium [1-14C]acetate radiolabel. The regulation of triunsaturated fatty acid components may be a potential control site in PUFA biosynthesis.

Balance retraining after stroke using force platform biofeedback.

Balance is a somewhat ambiguous term used to describe the ability to maintain or move within a weight-bearing posture without falling. Balance can further be broken down into three aspects: steadiness, symmetry, and dynamic stability. Steadiness refers to the ability to maintain a given posture with minimal extraneous movement (sway). The term symmetry is used to describe equal weight distribution between the weight-bearing components (eg, the feet in a standing position, the buttocks in a sitting position), and dynamic stability is the ability to move within a given posture without loss of balance. All of these components of balance (steadiness, symmetry, and dynamic stability) have been found to be disturbed following stroke. Balance testing of patients with hemiparesis secondary to stroke has revealed a greater amount of postural sway during static stance, asymmetry with greater weight on the nonparetic leg, and a decreased ability to move within a weight-bearing posture without loss of balance. Furthermore, research has demonstrated moderate relationships between balance function and gait speed (r = -.67 and .42, respectively), independence (r = .62), appearance (defined as "significantly abnormal," "slightly abnormal," and "nearly normal") (r = .50), dressing (r.55-.69), wheelchair mobility (r = .51), and reaching (r = .49-.78). Thus, a principal construct within physical therapy practice is the reestablishment of balance function in patients following stroke. Recent advances in technology have resulted in the commercial availability of numerous force platform systems for the retraining of balance function in patient populations, including patients with stroke. These systems are designed to provide visual or auditory biofeedback to patients regarding the locus of their center of force (COF) or center of pressure (COP), as well as training protocols to enhance stance symmetry, steadiness, and dynamic stability. Typical force platform biofeedback systems consist of at least two force plates to allow the weight on each foot to be determined, a computer and monitor to allow visualization of the COF or COP, and software that provides training protocols and data analysis capabilities. Some units allow auditory feedback in addition to the visual feedback in response to errors in performance.

Dimensions of deception in personality assessment: the example of the MMPI-2.

The topic of deception in personality assessment is discussed along a number of dimensions relevant to clinical practice. The dimensions described are consistency versus accuracy of item endorsement, simulation versus dissimulation, genetic versus specific deception, crude versus sophisticated deception, intentional versus nonintentional deception, self-deception versus impression management, and selectivity versus inclusiveness, as these may be encountered using the revised version of the Minnesota Multiphasic Personality Inventory. The emphasis is placed on deceptive strategies as operations as distinct from the traditional categories of response style such as social desirability. Directions for future research are indicated.

Remarks on method for MMPI-Rorschach studies.

An impressionistic list of methodological considerations that may be of consequence in Minnesota Multiphasic Personality Inventory (MMPI)-Rorschach studies is presented. These include the potential effects of the multidimensionality of the basic clinical MMPI scales in comparison studies, issues of deception and response style in such studies, and the rote of theory in guiding the selection of variables in the search for MMPI-Rorschach correspondences. The recently established necessity of controls for the total number of Rorschach responses provides the basis for suggestions for further controls in MMPI-Rorschach studies, including those for level of distress and for the minimization/exaggeration of psychopathology. An effort is made to contrast these two instruments in terms borrowed from information theory as a way of illuminating their complementary aspects, and suggesting means by which each may contribute to an enhanced understanding of the other.

Sitting balance: its relation to function in individuals with hemiparesis.

OBJECTIVES: To evaluate test-retest reliability of sitting balance measures in healthy subjects and individuals with hemiparesis secondary to stroke, to evaluate the ability of the balance measures and Functional Independence Measure (FIM) to document changes over time, and to compare changes in the balance measures and FIM to each other. METHOD: Six nonpatient subjects were evaluated for test-retest reliability. Fourteen subjects with hemiparesis were tested every 2 weeks during their hospitalization on their ability to lean to either side, lean forward, and maintain a symmetrical posture. Maximum displacement was recorded using the Balance System. FIM scores were obtained for each testing session. RESULTS: Test-retest reliability for nonpatient subjects was high and for patients was moderate to high. Leaning forward and to the paretic side showed the greatest number of correlations with the FIM scores. All of the FIM scales and the forward lean measure documented progress. CONCLUSIONS: The protocol developed to test sitting balance, using the Balance System, seems appropriate for use with patient populations. The ability to lean maximally to either side or forward or sit symmetrically is not strongly related to function.

Changes in the mean center of balance during balance testing in young adults.

BACKGROUND AND PURPOSE: The analysis of standing balance is now possible using commercially available force platforms. In order to establish appropriate testing and treatment protocols for patient populations, we contend data should be collected relative to the typical response of nonpatient groups. More importantly, we need to better understand response characteristics of persons with intact nervous systems. The purpose of this study was to evaluate the typical response of young adults without known musculoskeletal or neurological impairments to balance testing with the Balance System. SUBJECTS: Sixty-six subjects without known impairments (mean age = 23.6 years, SD = 4.5, range = 21-47) were evaluated in a single testing session. METHODS: Center of balance (COB), a vertical force measurement, was evaluated under each of 18 conditions: 2 visual conditions (eyes open, eyes closed), 3 platform conditions (stable, vertical tilt, linear translation), and 3 foot positions (apart, together, tandem). RESULTS: An effect was found for average displacement to the left along the x axis under all testing conditions. The COB locus along the y axis was dependent on the foot position, platform condition, and visual condition. CONCLUSION AND DISCUSSION: Movement of the COB toward the center of the base of support accompanied closing of the eyes, narrowing of the base of support, and movement of the support surface. These findings are consistent with the need to move the center of gravity away from the limits of stability under more challenging stance conditions. This study contributes to the existing knowledge base related to standing balance function in young adults without musculoskeletal or neurological impairments and provides data that can be used for criterion-based comparisons of young adult patients. [Nichols DS, Glenn TM, Hutchinson KJ. Changes in the mean center of pressure during balance testing.

Effects of vestibular rehabilitation and social reinforcement on recovery following ablative vestibular surgery.

This study investigated the relative effects of vestibular rehabilitation (VR) and social reinforcement (SR) on recovery following ablative vestibular surgery. Twenty-four subjects were randomly assigned to three treatment groups of either VR with SR, VR without SR, or general range of motion (ROM) exercises with SR. Outcome measures included equilibrium scores in dynamic posturography, asymmetry index in rotation testing, motion sensitivity quotient (MSQ), and dizziness handicap inventory (DHI). A multiple comparison of the overall outcome measures showed no significant differences in group performance over an 8-week period. When individual outcome measures were compared, MSQ and DHI results at the end of the 8-week treatment period revealed less motion sensitivity and dizziness handicap in groups who received VR, with or without SR, as compared with the group who received ROM exercises. These results suggest that after a vestibular injury most patients can effectively utilize central compensation mechanisms to recover from such an injury, regardless of the type of therapeutic intervention used. On the other hand, the reduction in motion sensitivity and dizziness handicap for patients who received VR could indicate a more rapid and complete recovery for these patients. This investigation is continuing as a long-term follow-up study to determine whether there are any long-term benefits in participating in a VR program.

Effects of aerobic exercise on pain perception, affect, and level of disability in individuals with fibromyalgia.

BACKGROUND AND PURPOSE: The purpose of this study was to evaluate the effect of aerobic walking on the pain, disability, and psychological symptoms of individuals with fibromyalgia. SUBJECTS: Nineteen subjects with fibromyalgia (2 men, 17 women), aged 30 to 69 years (mean = 49.35, SD = 11.83), participated. METHODS: Ten subjects walked 20 minutes, three times per week, for 8 weeks at 60% to 70% of the predicted maximum heart rate for their age. Nine subjects served as sedentary controls. Each subject completed pretests and posttests of the McGill Pain Questionnaire (MPQ), the Sickness Impact Profile (SIP), and the Brief Symptom Inventory (BSI). Due to initial differences on all measures, final scores were adjusted and analyzed by an analysis of covariance. RESULTS: The experimental group had lower scores on the MPQ on two of the three BSI indexes, and on the Psychosocial Dimension scale of the SIP, but higher ratings on the Physical Dimension scale of the SIP than did the control group on final testing. Only the differences on one index of the BSI and the Physical Dimension scale of the SIP were significant. CONCLUSION AND DISCUSSION: The results of the study are inconclusive. There were trends suggestive of a beneficial response to aerobic walking (lower psychological and pain ratings) but limited significant findings and higher physical disability ratings, for these individuals with fibromyalgia.

Stimulation-produced analgesia and its cross-tolerance between dorsal and ventral PAG loci.

This study explored the development of tolerance to brain stimulation-produced analgesia in both dorsal and ventral periaqueductal gray (PAG) sites and the development of cross-tolerance between naloxone-reversible and non-reversible sites. Cross-tolerance was produced from non-naloxone-reversible sites to naloxone-reversible sites (NNR-NR) and from naloxone-reversible sites to non-naloxone-reversible sites (NR-NNR). The following conclusions can be drawn from the present study: (1) the descending pain inhibitory systems within the PAG do not operate in isolation of each other since cross-tolerance to chronic stimulation can be produced between systems; (2) the interaction between the two systems is apparently bi-directional in that cross-tolerance was produced from naloxone-reversible to non-reversible sites and vice versa; and (3) the interaction may be the result of a co-activation of opioid and non-opioid systems produced by electrical stimulation or by a co-utilization of a common neuronal substrate. It is speculated that serotonin is a neurotransmitter involved in the mechanism of convergence.

Opiate and serotonergic mechanisms of stimulation-produced analgesia within the periaqueductal gray.

These studies investigated the distribution of analgesia-producing sites within the periaqueductal gray (PAG), and their potential reversal by naloxone and methysergide. The PAG is not differentiable in its ability to elicit stimulation-produced analgesia (SPA) until the point of stimulation is caudal to the dorsal raphe nucleus, where analgesia was not obtained. Naloxone, however, was found to have a differential effect at specific loci, significantly reducing SPA from ventral but not dorsal sites. In contrast, methysergide was effective in reversing analgesia both at ventral and dorsal sites. The site of stimulation was critical to whether motor effects were elicited: Motor effects accompanied by analgesia were most often produced rostrally, while motor effects without analgesia were most frequently produced in the middle PAG. Null effects for both motor activity and analgesia were obtained from caudal PAG sites.