Influence of Chemical Nature of Citric and Tartaric Acids on Reaction Time of the Crosslinking of Polyvinyl Alcohol Hydrogels.

Poly(vinyl alcohol) (PVOH) is a water-soluble polymer having a hydroxyl group as a functional group contributing to excellent membrane-forming and mechanical performance. PVOH is obtained by the hydrolysis of polyvinyl acetate, and its physical properties are affected by its degree of hydrolysis, whether, partial or complete. In this study, PVOH hydrogels were synthesized by a solution under stirring and heating techniques with citric (AC) and tartaric acids (AT) crosslinker agents, with different time reactions of 20 min.; 1; 2, and 3 h were investigated. These samples were characterized by the kinetics of water uptake, gel fraction, thermal analysis, and physical-chemical analysis, and their structure was elucidated. The results obtained have shown chemical modification by organic acids and improved the properties to good thermal stability and swelling to AT hydrogels up to 900% water uptake. In the gel fraction, the samples' esterification was shown and verified by FTIR spectra. To AC hydrogels the chemical modification was low due to the steric hindrance, which caused disintegration of the hydrogel in swelling and gel fraction test, but with absorption in the moisture test performed. The incorporation and effects of citric and tartaric acids enable the development of new hydrogel systems, with specific properties.

Deaf and hearing children: A comparison of face perception.

Deaf and hearing adults perceive faces differently. This study investigates whether these differences are acquired during childhood development. We characterized facial perception in deaf and hearing children aged 7-17 using a perceptual discrimination task. Configural and featural information was manipulated in the eye and mouth facial regions. Participants were asked whether two faces presented simultaneously were different. Deaf and hearing children performed better in featural than configural discriminations and in mouth than eye discriminations. Compared with children with typical hearing, deaf children performed better in featural and mouth judgments but had longer reaction times with strongest effects at 7-8 and 13-14 years old. Type and location contributed jointly in deaf children's face perception with different configural but similar featural discriminations in mouth and eye locations. However, children with typical hearing showed different featural and configural judgments in both locations. Thus, featural and configural information effects on location processing differ between the two groups.

The effect of mouth rinsing with different concentrations of caffeine solutions on reaction time.

Caffeine mouth rinsing (CAF-MR) has been shown to improve reaction time (RT). CAF-MR studies have generally used 1.2% CAF concentrations, but the effect of using different concentrations is unknown. Therefore, we compared the effect of different concentrations of CAF-MR on RT. Forty-five trained male athletes (age: 18 ± 3 y) volunteered to participate in this double-blind, randomized controlled crossover study. Participants completed five testing sessions (Control, Placebo (water)-MR, and 1.2%, 1.8%, and 2.4% CAF-MR), with hand and foot RTs assessed immediately after MR. All CAF-MR conditions resulted in significantly faster hand and foot RT compared to Control and Placebo (all p < 0.001, except for foot RT with 1.8% CAF-MR vs. Placebo: NS). For both hand and foot RT, 1.2% and 1.8% CAF-MR did not significantly differ, but RT for 2.4% CAF-MR was significantly faster than both (p < 0.001). Improvements in RT for 2.4% CAF-MR vs. Placebo were 22% for hand RT and 21% for foot RT. In conclusion, these findings demonstrate that higher CAF-MR concentrations than those typically used can result in greater improvements in RT. This has implications for the practical use of CAF-MR to enhance performance in sports in which optimal RT is a factor of success.

Analysis of the effects of hypothalamic-pituitary-adrenal axis activity in menstrual cycle on ankle proprioception, dynamic balance scores and visual-auditory reaction times in healthy young women.

OBJECTIVES: Menstrual cycle (MC) can affect not only the female reproductive system, but also functions such as neuromuscular performance. For this reason, the aim of this study is to investigate the effect of hypothalamic-pituitary-adrenal axis (HPA) activity in MC on proprioception, balance and reaction times. METHODS: For cortisol analysis, saliva samples were taken from the same women (n=43) in the four phases of MC. While State Trait Anxiety Inventory-I (STAI-I) was applied in each phase to support cortisol analysis, pain was measured with visual analogue scale (VAS). Proprioception, dynamic balance, visual and auditory reaction times (VRT-ART) measurements were made in the four phases of MC. RESULTS: Cortisol, STAI-I and VAS scores, angular deviations in proprioception measurements, dynamic balance scores, VRT and ART measurements were found to show statistically significant difference between MC phases (p<0.05). As a result of the post hoc test conducted to find out which MC phase the statistical difference resulted from, it was found that statistically significant difference was caused by the mensturation (M) phase (p<0.05). CONCLUSIONS: It was found that neuromuscular performance and postural control was negatively affected by HPA axis activity in M phase of MC and by pain, which is a significant menstrual symptom.

Effects of vasopressin on anesthetic response time and circulatory dynamics of lidocaine.

This study aimed to investigate the hypothesis that vasopressin extends the anesthetic response time of lidocaine and does not affect the circulatory dynamics. Rats were sedated with isoflurane; subsequently, breathing was maintained through mechanical ventilation. We infiltrated the first molar area of the upper left jaw with saline (NS, test solution), 2% lidocaine (L), 0.025 IU vasopressin-supplemented 2% lidocaine, 0.05 IU vasopressin-supplemented 2% lidocaine, 0.1 IU vasopressin-supplemented 2% lidocaine, and 0.2 IU vasopressin-supplemented 2% lidocaine (VL4). Further, anesthetic response times were measured up to 30 min using electric pulp testing methods (n = 4). The anesthetic response times of NS, L, and VL4 were measured up to 45 min with the aforementioned results as reference values (n = 7). The circulatory dynamics of NS, L, VL4, and 0.2 IU vasopressin (V) were measured up to 45 min using a non-invasive blood pressure measuring device. VL4 extended the anesthetic response times of lidocaine compared to L (p < 0.05). Further, V and VL4 significantly increased the systolic and diastolic blood pressure and significantly decreased the pulse rate (p < 0.05). VL4 is not a suitable addition to the local anesthetic solution used in dentistry. Further study is needed to determine vasopressin concentration that extends the anesthetic effect without affecting the circulatory dynamics.

Scheduled afternoon-evening sleep leads to better night shift performance in older adults.

OBJECTIVES: This study investigated whether an intervention designed to reduce homeostatic sleep pressure would improve night shift performance and alertness in older adults. METHODS: Non-shift workers aged 57.9±4.6 (mean±SD) worked four day (07:00-15:00) and four night shifts (23:00-07:00). Two intervention groups were instructed to remain awake until ~13:00 after each night shift: the sleep timing group (ST; n=9) was instructed to spend 8 hours in bed attempting sleep, and the sleep ad-lib group (n=9) was given no further sleep instructions. A control group (n=9) from our previous study was not given any sleep instructions. Hourly Karolinska Sleepiness Scales and Psychomotor Vigilance Tasks assessed subjective sleepiness and performance. RESULTS: The ST group maintained their day shift sleep durations on night shifts, whereas the control group slept less. The ST group were able to maintain stable performance and alertness across the initial part of the night shift, while the control group's alertness and performance declined across the entire night. Wake duration before a night shift negatively impacted sustained attention and self-reported sleepiness but not reaction time, whereas sleep duration before a night shift affected reaction time and ability to sustain attention but not self-reported sleepiness. CONCLUSIONS: A behavioural change under the control of the individual worker, spending 8 hours in bed and waking close to the start of the night shift, allowed participants to acquire more sleep and improved performance on the night shift in older adults. Both sleep duration and timing are important factors for night shift performance and self-reported sleepiness.

Reconsolidation impairment of reward memory by stimulating stress response.

Research in memory reconsolidation has raised hope for new treatment options of persistent psychiatric disorders like substance dependence and post-traumatic stress disorder (PTSD). While animal research showed successful memory modification by interfering with reconsolidation, human research requires less invasive techniques. In our pilot study, we aimed to reduce appetitive memory reconsolidation of a newly acquired reward memory by exerting a stressor. Thirty healthy participants were randomly assigned to two groups performing a monetary reward paradigm at a personal computer. Day 1 was considered to allow for memory acquisition; on day 2, the experimental group was exposed to a frightening stimulus in the reconsolidation window; and day 3 again served to determine reward memory effects. Measures of reward memory were reaction times to reward announcing stimuli (ie, showing instrumental behavior), actual reward gained, and electrodermal response as a measure for reward anticipation. We found significantly smaller reaction time improvements to reward stimuli over time in the experimental group, as well as reduced achievements in monetary reward. Electrodermal response to reward announcing stimuli was lower in the experimental group after intervention, whereas it was higher in the untreated group. Thus, we argue in favor of the reconsolidation hypothesis, assuming our intervention had successfully interfered with the reconsolidation process. This points towards future treatment options that interfere with an addiction memory.

A pilot study on salivary cortisol secretion and auditory P300 event-related potential in patients with physical disability-related stress.

Objective: To evaluate the stress level and attention in workers with physical disabilities-related stress.Methods: Morning salivary cortisol was used as a stress marker while the event-related potential during the performance of the auditory oddball paradigm was conducted to investigate the attentive ability to sound stimuli. Eighteen injured workers (IP) and eighteen unaffected healthy adults (CP) were recruited for this study with half being men and the other half women (aged 21-55). Behavioral performance measures including reaction time (RT), accuracy rate, and commission error as well as the latency and amplitude of P300 wave over the central (Cz), centroparietal (CPz), and parietal (Pz) electroencephalogram electrode sites were used to compare the two groups.Results: This study demonstrated significantly higher salivary cortisol levels, longer RT, less accuracy to respond to the target during the auditory oddball paradigm in the IP group as compared to CP group. In addition, a significant prolongation of the peak latency of auditory P300 wave over CPz electrodes was also detected in IP group.Conclusion: The increased cortisol levels found in the IP group reflect the alteration of the basal hypothalamic-pituitary-adrenal axis as a result of the stresses of living with a physical disability. Delayed RT and the decreased in accuracy together with changing in peak latencies of auditory P300 wave indicate the impairment of attention networks in IP. Our study revealed that the patients with permanent physical disability.

Is it safe to drive after oral surgery?

OBJECTIVES: Driving ability largely depends on the total brake response time (TBRT) corresponding to the time a subject needs to react to a stimulus and apply a well-defined force on the brake pedal. As yet, the English literature completely lacks clinical studies evaluating the TBRT following oral surgery. MATERIALS AND METHODS: In this case-control study, a driving simulator was used to evaluate the TBRT in patients scheduled for oral surgery in local anesthesia. Measurements were taken shortly before (t1) and after (t2) surgery as well as 7-10 days later (t3) when sutures were removed. Results were compared to data of a group of healthy volunteers. RESULTS: Seventy-three patients (37 women, 36 men) underwent evaluation at t1, t2, and t3. In 13 patients who did not return for removal of sutures, only measurements at t1 and t2 could be performed. The median TBRT was 583 milliseconds (ms), 634 ms, and 520 ms at t1, t2, and t3, respectively. Statistical analysis revealed significant differences between readings at t1 versus t2 (t = - 4.944, p < 0.001), t1 versus t3 (t = 7.454, p < 0.001), and t2 versus t3 (t = 11.971, p < 0.001). There was no significant difference between TBRT at t3 in study subjects compared to normal reference values of 67 healthy volunteers. TBRT was significantly increased immediately after oral surgery (t2) compared to measurements 7-10 days postoperatively (t3). Since readings at t3 did not differ from TBRT values in the comparison group, they were considered normal. CONCLUSIONS: Due to significantly elevated total brake response time, driving ability is assumed to be considerably affected following oral surgery, and patients should be advised to abstain from driving immediately after such operations. CLINICAL RELEVANCE: Our study results put into question patients' driving ability following dentoalveolar procedures which should be considered regarding informed consent and could potentially have consequences on health issues (road traffic accidents) as well as legal and financial matters (court charges, insurance claims).

How does cognitive function measured by the reaction time and critical flicker fusion frequency correlate with the academic performance of students?

BACKGROUND: The reaction time (RT) is "the time taken for the appearance of rapid voluntary reaction by an individual following a stimulus, either auditory or visual" and the Critical Flickering Fusion Frequency (CFFF) is "the rate at which successively presented light stimuli appear to be steady and continuous". RT and CFFF are commonly used for the assessment of cognitive functions that are known to influence academic performance. However, data about the exact correlation between these are scarce, particularly in India. This research aimed to study the association between visual RT (VRT), auditory RT (ART) and CFFF and their impact on the academic performance of undergraduate students. METHODS: This cross-sectional study was conducted on 700 students of Faculty of Medicine and Dentistry at a private medical university in South India, during the period from 2015 to 2017. The VRT, ART and CFFF were evaluated, and the best out of three subsequent attempts was recorded. The mean score (in percentage) of the three best marks out of the five internal assessments for the course during each academic year was considered for analysis. The association between the different cognitive tests and the average academic performance was analysed. RESULTS: Female students had faster VRT (n = 345, mean = 243.97, SD = 83.87) than male students (n = 273, mean = 274.86, SD = 96.97) (p = 0.001). VRT and ART had a moderate negative correlation with academic performance (for ART, r = - 0.42, p < 0.001; for VRT; r = - 0.40, p < 0.001). CFFF had a very weak positive correlation with academic performance (r = 0.19, p = 0.01). The only independent predictors of academic performance were RT and gender (Adjusted R2 = 0.11). CONCLUSION: Although there is a correlation between CFFF and cognitive function, our study showed only a weak correlation between CFFF and academic performance. Female students had faster RTs, and gender was an independent predictor of academic performance. Rather, students with faster RTs appear to have an advantage in academic performance.

Acute stress enhances the sensitivity for facial emotions: a signal detection approach.

Facial emotion recognition is an important prerequisite for social cognition. There is, however, limited evidence on how the ability to detect facial emotions is influenced by acute stress and the associated physiological reactions. In this study, two groups of healthy male participants were either exposed to a psychosocial stressor - an adaptation of the Trier Social Stress Test in virtual reality (n = 23) - or a non-stressful control task in the virtual environment (n = 20). Afterwards, both groups completed a computerized facial recognition task based on the signal detection theory presenting happy vs. angry faces with three different expression intensities. Saliva samples were taken at seven time points over the course of the experiment and used to analyze concentrations of free salivary cortisol and alpha amylase. Analyses using repeated-measures analyses of variance revealed a significant increase in emotion detection performance and significantly shorter response latencies in the stress group independent of emotional valence or emotion intensity. However, increased task performance in the stress group could not be predicted by stress-induced cortisol or alpha amylase secretion. The results suggest that enhanced detection of emotional cues after stress might be an adaptive response as an increased sensitivity to social cues might help individuals to detect potential threats or sources of social support in their social environment. Lay Summary Socially evaluative stress facilitates the subsequent recognition of emotions. After having performed a task in a virtual environment, two groups of participants were asked to detect emotion expressions on pictures of faces that were presented to them on a computer screen. Statistical comparison of groups indicates that the group that had previously been subjected to a stressful job interview showed better results and became faster in detecting displayed emotions than the control group that had previously performed a non-stressful task.

First-in-man study of ACT-709478, a novel selective triple T-type calcium channel blocker.

OBJECTIVE: Increased activity of T-type Ca2+ channels is linked to idiopathic generalized epilepsies, thus blocking these channels may be a new treatment option. ACT-709478 is an orally available triple T-type Ca2+ channel blocker. The aim of this first-in-man study was to investigate the pharmacokinetics, pharmacodynamics, tolerability, and safety of single doses of ACT-709478 in healthy subjects. METHODS: This double-blind, placebo-controlled, randomized study included 65 healthy male subjects. Ascending single oral doses of 1-400 mg ACT-709478 or placebo were administered to sequential groups of eight subjects (6 on active, 2 on placebo). Effect of food was tested in a crossover part at 60 mg. Blood and saliva sampling for pharmacokinetic evaluations and safety assessments was performed regularly. Effects on the central nervous system were assessed with a battery of pharmacodynamic tests. RESULTS: The maximum plasma concentration (Cmax ) was reached within 3 to 4 hours (≤60 mg) and within 20 to 28 hours (>60 mg), and across all dose levels the terminal half-life (95% confidence interval) ranged from 36 (29-45) to 43 (22-86) hours. Multiple peaks were observed and Cmax and area under the plasma concentration-time curve (AUC)0-∞ increased in a less than dose-proportional manner. A 1.6-fold increase in Cmax and no change in AUC0-∞ was observed in fed compared to fasted conditions. A significant correlation (P < 0.0001) between plasma and saliva concentrations was established using linear regression. All adverse events were transient and of mild or moderate intensity. No treatment-related effects on vital signs, clinical laboratory, telemetry, or electrocardiography were detected. The results of pharmacodynamic tests did not show relevant mean changes compared to baseline or placebo. SIGNIFICANCE: ACT-709478 exhibits good tolerability and safety after single-dose administration and its pharmacokinetic and pharmacodynamic properties warrant further investigations.

Influence of two functional polymorphisms in NOS1 on baseline cortisol and working memory in healthy subjects.

INTRODUCTION: The neuronal isoform of the nitric oxide synthase (NOS-I) encoded by NOS1 is the main source of nitric oxide (NO) in the brain. Reduced NO signaling in the prefrontal cortex has been linked to schizophrenia and cognitive processes while reduced striatal NOS1 expression has been associated with impulsive behavior. METHODS: To evaluate the effect of two functional polymorphisms in alternative first exons of NOS1, ex1f-VNTR and ex1c-SNP rs41279104, on the HPA stress axis and neurocognitive abilities, 280 healthy subjects were genotyped, had their salivary cortisol levels measured and were assessed in verbal memory, verbal fluency, working memory and verbal IQ by using the California Verbal Learning Test (CVLT), the Regensburger test of verbal fluency (RWT), a n-back task and subscales of the Wechsler Adult Intelligence Scale III (WAIS-III). RESULTS: Schizophrenia risk (A)-allele carriers of NOS1 ex1c-SNP rs41279104 displayed significantly lower baseline cortisol levels (p = 0.004). NOS1 ex1f-VNTR genotype carriers showed differences in working memory performance (p = 0.05) in a gene-dose effect manner, with homozygous carriers of the short impulsivity-risk allele committing most commission errors. Finally, A-allele carriers of the NOS1 ex1c-SNP rs41279104 tended to react faster during the working memory task (p = 0.065). CONCLUSION: For the first time, we demonstrated an influence of the NOS1 ex1c-SNP rs41279104 on salivary cortisol levels and additionally implicate the A-allele in an enhanced reaction time during a working memory task. Regarding the NOS1 ex1f-VNTR our study supports the previously reported influence on impulsivity, lending further support to the hypothesis that this genetic variant underlies impulsive behavior.

P300 values in patients diagnosed with primary Sjogren syndrome.

PURPOSE: Primary Sjogren syndrome (PSS) is an autoimmune disease characterized by symptoms of a dry mouth and eyes, in which other organs and systems are widely involved. Central nervous system (CNS) involvement in PSS is reported in a wide range between 2.5-60%. The reason is that the clinical picture can remain asymptomatic despite the presence of CNS involvement in the disease process. In this study, our aim was to evaluate subclinical cognitive impairment in patients with PSS by investigating P300 potential parameters. METHOD: Forty-three female patients with PSS (mean age: 52.6 ± 11.4 years) and 35 healthy female controls (mean age: 54.5 ± 8.09 years) were included in the study. Mini-Mental State evaluations (MMSE) and brain MRI were performed in the patient and control groups. An event-related evoked potentials test (P300) was applied to those with normal MMSE. RESULTS: The P300 latencies of patients with PSS were significantly longer compared with the control group (p = .019). In patients with PSS, there was no difference in P300 parameters between ANA, Anti-SSA, Anti-SSB-positive and negative patients, and patients with or without sedimentation and CRP elevation. In addition, brain MRI revealed no statistically significant difference between patients with PSS with and without ischemic gliotic lesions (p=.48). CONCLUSION: In our study, P300 latency was also found to be significantly longer in patients who had no white matter change. We believe that prolonged P300 potential latencies without associated white matter lesions in brain imaging may be associated with subclinical CNS involvement.

Inferring Mental States From Dynamic Faces in Adolescents With Autism Spectrum Disorder: Insights From Eye Tracking.

There is mixed evidence concerning whether individuals with autism spectrum disorder (ASD) can infer mental states from the eyes. This study aims to elucidate whether they use less efficient strategies. Sixteen adolescents with ASD (11-16 year olds) were compared to a chronological age- and IQ-matched sample of 16 typically developing (TD) adolescents. Eight mental states were presented as full dynamic faces and in conditions altering the presence of expressive dynamic information from the eyes and mouth. Bayes factors revealed that adolescents with ASD had similar accuracy, response times (less conclusive), and fixations to TD adolescents. Findings imply that adolescents with ASD spontaneously fixate on the eyes, and not all individuals with ASD have difficulties inferring mental states from faces.

Changes in Event-Related Potentials Underlying Coma Recovery in Patients with Large Left Hemispheric Infarction.

BACKGROUND The aim of this study was to investigate changes in event-related potentials (ERPs) between coma and awakening in patients with large left hemispheric infarction (left LHI). MATERIAL AND METHODS Ten patients with left LHI who suffered coma and survived to awaken were enrolled in this study. The eye-opening subscore of the Glasgow Coma Scale (GCS) was used to assess the extent of patients' arousal. ERPs elicited by the passive oddball paradigm were collected during coma and awakening states, respectively. Peak latencies, peak amplitudes, topography, and time-frequency information of P1, N1, P2, and mismatch negativity (MMN) were compared between the 2 sessions. RESULTS No significant differences in the peak amplitudes and peak latencies of P1 and N1, but significantly greater P2 amplitude with shorter latency in left hemisphere and midline was shown in the awakening state compared with that in coma. A marked shift of P2 topography in response to deviant tones was also seen, from the right centro-parieto-frontal areas during coma to left frontal-midline areas during awakening. MMN waveforms were not detected in 6/10 patients during the coma state, but these 6 patients all recovered to awakening. Evoked oscillations in bilateral hemisphere were profoundly inhibited during the coma state, with poor inter-trial phase synchronization, while obvious activities with broader frequency ranges and consistent inter-trial phase synchronization were observed during awakening state, and different frequency activities were distributed in distinct brain regions. CONCLUSIONS P2 may be a central index of coma recovery and a component of the arousal system. Changes in time-frequency information could provide more information during coma recovery, perhaps including some cognitive processing of the sensory stimulus.

Neural correlates of emotional action control in anger-prone women with borderline personality disorder.

BACKGROUND: Difficulty in controlling emotional impulses is a crucial component of borderline personality disorder (BPD) that often leads to destructive, impulsive behaviours against others. In line with recent findings in aggressive individuals, deficits in prefrontal amygdala coupling during emotional action control may account for these symptoms. METHODS: To study the neurobiological correlates of altered emotional action control in individuals with BPD, we asked medication-free, anger-prone, female patients with BPD and age- and intelligence-matched healthy women to take part in an approach-avoidance task while lying in an MRI scanner. The task required controlling fast behavioural tendencies to approach happy and avoid angry faces. Additionally, before the task we collected saliva testosterone and self-reported information on tendencies to act out anger and correlated this with behavioural and functional MRI (fMRI) data. RESULTS: We included 30 patients and 28 controls in our analysis. Patients with BPD reported increased tendencies to act out anger and were faster in approaching than avoiding angry faces than with healthy women, suggesting deficits in emotional action control in women with BPD. On a neural level, controlling fast emotional action tendencies was associated with enhanced activation in the antero- and dorsolateral prefrontal cortex across groups. Healthy women showed a negative coupling between the left dorsolateral prefrontal cortex and right amygdala, whereas this was absent in patients with BPD. LIMITATIONS: Specificity of results to BPD and sex differences remain unknown owing to the lack of clinical control groups and male participants. CONCLUSION: The results indicate reduced lateral prefrontal-amygdala communication during emotional action control in anger-prone women with BPD. The findings provide a possible neural mechanism underlying difficulties with controlling emotional impulses in patients with BPD.

Sensory Cortical Activity Is Related to the Selection of a Rhythmic Motor Action Pattern.

UNLABELLED: Rats produce robust, highly distinctive orofacial rhythms in response to taste stimuli-responses that aid in the consumption of palatable tastes and the ejection of aversive tastes, and that are sourced in a multifunctional brainstem central pattern generator. Several pieces of indirect evidence suggest that primary gustatory cortex (GC) may be a part of a distributed forebrain circuit involved in the selection of particular consumption-related rhythms, although not in the production of individual mouth movements per se. Here, we performed a series of tests of this hypothesis. We first examined the temporal relationship between GC activity and orofacial behaviors by performing paired single-neuron and electromyographic recordings in awake rats. Using a trial-by-trial analysis, we found that a subset of GC neurons shows a burst of activity beginning before the transition between nondistinct and taste-specific (i.e., consumption-related) orofacial rhythms. We further showed that shifting the latency of consumption-related behavior by selective cueing has an analogous impact on the timing of GC activity. Finally, we showed the complementary result, demonstrating that optogenetic perturbation of GC activity has a modest but significant impact on the probability that a specific rhythm will be produced in response to a strongly aversive taste. GC appears to be a part of a distributed circuit that governs the selection of taste-induced orofacial rhythms. SIGNIFICANCE STATEMENT: In many well studied (typically invertebrate) sensorimotor systems, top-down modulation helps motor-control regions "select" movement patterns. Here, we provide evidence that gustatory cortex (GC) may be part of the forebrain circuit that performs this function in relation to oral behaviors ("gapes") whereby a substance in the mouth is rejected as unpalatable. We show that GC palatability coding is well timed to play this role, and that the latency of these codes changes as the latency of gaping shifts with learning. We go on to show that by silencing these neurons, we can change the likelihood of gaping. These data help to break down the sensory/motor divide by showing a role for sensory cortex in the selection of motor behavior.

Supratrigeminal Bilaterally Projecting Neurons Maintain Basal Tone and Enable Bilateral Phasic Activation of Jaw-Closing Muscles.

UNLABELLED: Anatomical studies have identified brainstem neurons that project bilaterally to left and right oromotor pools, which could potentially mediate bilateral muscle coordination. We use retrograde lentiviruses combined with a split-intein-mediated split-Cre-recombinase system in mice to isolate, characterize, and manipulate a population of neurons projecting to both the left and right jaw-closing trigeminal motoneurons. We find that these bilaterally projecting premotor neurons (BPNs) reside primarily in the supratrigeminal nucleus (SupV) and the parvicellular and intermediate reticular regions dorsal to the facial motor nucleus. These BPNs also project to multiple midbrain and brainstem targets implicated in orofacial sensorimotor control, and consist of a mix of glutamatergic, GABAergic, and glycinergic neurons, which can drive both excitatory and inhibitory inputs to trigeminal motoneurons when optogenetically activated in slice. Silencing BPNs with tetanus toxin light chain (TeNT) increases bilateral masseter activation during chewing, an effect driven by the expression of TeNT in SupV BPNs. Acute unilateral optogenetic inhibition of SupV BPNs identifies a group of tonically active neurons that function to lower masseter muscle tone, whereas unilateral optogenetic activation of SupV BPNs is sufficient to induce bilateral masseter activation both during resting state and during chewing. These results provide evidence for SupV BPNs in tonically modulating jaw-closing muscle tone and in mediating bilateral jaw closing. SIGNIFICANCE STATEMENT: We developed a method that combines retrograde lentiviruses with the split-intein-split-Cre system in mice to isolate, characterize, and manipulate neurons that project to both left and right jaw-closing motoneurons. We show that these bilaterally projecting premotor neurons (BPNs) reside primarily in the supratrigeminal nucleus and the rostral parvicellular and intermediate reticular nuclei. BPNs consist of both excitatory and inhibitory populations, and also project to multiple brainstem nuclei implicated in orofacial sensorimotor control. Manipulation of the supratrigeminal BPNs during natural jaw-closing behavior reveals a dual role for these neurons in eliciting phasic muscle activation and in maintaining basal muscle tone. The retrograde lentivirus carrying the split-intein-split-Cre system can be applied to study any neurons with bifurcating axons innervating two brain regions.

Testosterone during Puberty Shifts Emotional Control from Pulvinar to Anterior Prefrontal Cortex.

UNLABELLED: Increased limbic and striatal activation in adolescence has been attributed to a relative delay in the maturation of prefrontal areas, resulting in the increase of impulsive reward-seeking behaviors that are often observed during puberty. However, it remains unclear whether and how this general developmental pattern applies to the control of social emotional actions, a fundamental adult skill refined during adolescence. This domain of control pertains to decisions involving emotional responses. When faced with a social emotional challenge (e.g., an angry face), we can follow automatic response tendencies and avoid the challenge or exert control over those tendencies by selecting an alternative action. Using an fMRI-adapted social approach-avoidance task, this study identifies how the neural regulation of emotional action control changes as a function of human pubertal development in 14-year-old adolescents (n = 47). Pubertal maturation, indexed by testosterone levels, shifted neural regulation of emotional actions from the pulvinar nucleus of the thalamus and the amygdala to the anterior prefrontal cortex (aPFC). Adolescents with more advanced pubertal maturation showed greater aPFC activity when controlling their emotional action tendencies, reproducing the same pattern consistently observed in adults. In contrast, adolescents of the same age, but with less advanced pubertal maturation, showed greater pulvinar and amygdala activity when exerting similarly effective emotional control. These findings qualify how, in the domain of social emotional actions, executive control shifts from subcortical to prefrontal structures during pubertal development. The pulvinar and the amygdala are suggested as the ontogenetic precursors of the mature control system centered on the anterior prefrontal cortex. SIGNIFICANCE STATEMENT: Adolescents can show distinct behavioral problems when emotionally aroused. This could be related to later development of frontal regions compared with deeper brain structures. This study found that when the control of emotional actions needs to be exerted, more mature adolescents, similar to adults, recruit the anterior prefrontal cortex (aPFC). Less mature adolescents recruit specific subcortical regions, namely the pulvinar and amygdala. These findings identify the subcortical pulvino-amygdalar pathway as a relevant precursor of a mature aPFC emotional control system, opening the way for a neurobiological understanding of how emotion control-related disorders emerge during puberty.