Development of a novel rodent rapid serial visual presentation task reveals dissociable effects of stimulant versus nonstimulant treatments on attentional processes.

The rapid serial visual presentation (RSVP) task and continuous performance tasks (CPT) are used to assess attentional impairments in patients with psychiatric and neurological conditions. This study developed a novel touchscreen task for rats based on the structure of a human RSVP task and used pharmacological manipulations to investigate their effects on different performance measures. Normal animals were trained to respond to a target image and withhold responding to distractor images presented within a continuous sequence. In a second version of the task, a false-alarm image was included, so performance could be assessed relative to two types of nontarget distractors. The effects of acute administration of stimulant and nonstimulant treatments for ADHD (amphetamine and atomoxetine) were tested in both tasks. Methylphenidate, ketamine, and nicotine were tested in the first task only. Amphetamine made animals more impulsive and decreased overall accuracy but increased accuracy when the target was presented early in the image sequence. Atomoxetine improved accuracy overall with a specific reduction in false-alarm responses and a shift in the attentional curve reflecting improved accuracy for targets later in the image sequence. However, atomoxetine also slowed responding and increased omissions. Ketamine, nicotine, and methylphenidate had no specific effects at the doses tested. These results suggest that stimulant versus nonstimulant treatments have different effects on attention and impulsive behaviour in this rat version of an RSVP task. These results also suggest that RSVP-like tasks have the potential to be used to study attention in rodents.

Evidence against implicit belief processing in a blindfold task.

Understanding what other people think is crucial to our everyday interactions. We seem to be affected by the perspective of others even in situations where it is irrelevant to us. This intrusion from others' perspectives has been referred to as altercentric bias and has been suggested to reflect implicit belief processing. There is an ongoing debate about how robust such altercentric effects are and whether they indeed reflect true mentalizing or result from simpler, domain-general processes. As a critical test for true mentalizing, the blindfold manipulation has been proposed. That is, participants are familiarized with a blindfold that is either transparent or opaque. When they then observe a person wearing this blindfold, they can only infer what this person can or cannot see based on their knowledge of the blindfold's transparency. Here, we used this blindfold manipulation to test whether participants' reaction times in detecting an object depended on the agent's belief about the object's location, itself manipulated with a blindfold. As a second task, we asked participants to detect where the agent was going to look for the object. Across two experiments with a large participant pool (N = 234) and different settings (online/lab), we found evidence against altercentric biases in participants' response times in detecting the object. We did, however, replicate a well-documented reality congruency effect. When asked to detect the agent's action, in turn, participants were biased by their own knowledge of where the object should be, in line with egocentric biases previously found in false belief reasoning. These findings suggests that altercentric biases do not reflect belief processing but lower-level processes, or alternatively, that implicit belief processing does not occur when the belief needs to be inferred from one's own experience.

Electrophysiological signature of the interplay between habits and inhibition in response to smoking-related cues in individuals with a smoking habit: An event-related potential study.

The rigid, stimulus-bound nature of drug seeking that characterizes substance use disorder (SUD) has been related to a dysregulation of motivational and early attentional reflexive and inhibitory reflective systems. However, the mechanisms by which these systems are engaged by drug-paired conditioned stimuli (CSs) when they promote the enactment of seeking habits in individuals with a SUD have not been elucidated. The present study aimed behaviourally and electrophysiologically to characterize the nature of the interaction between the reflexive and reflective systems recruited by CSs in individuals with a smoking habit. We measured the behavioural performance and associated event-related potentials (ERPs) of 20 individuals with a smoking habit and 20 controls, who never smoked regularly, in a modified Go/NoGo task during which smoking-related CSs, appetitive and neutral pictures, presented either in first or third-person visual perspective were displayed 250 ms before the Go/NoGo cue. We show that smoking-related cues selectively influence early incentive motivation-related attention bias (N2 after picture onset), motor readiness and behavioural inhibition (Go-P3, NoGo-P3 and Pc) of individuals with a smoking habit only when presented from a first-person visual perspective. These data together identify the neural signature of the aberrant engagement of the reflexive and reflective systems during the recruitment of an incentive habit by CSs presented as if they had been response-produced, that is, as conditioned reinforcers.

Compatibility effects with touchless gestures.

Human actions are suspect to various compatibility phenomena. For example, responding is faster to the side where a stimulus appears than to the opposite side, referred to as stimulus-response (S-R) compatibility. This is even true, if the response is given to a different stimulus feature, while location itself is irrelevant (Simon compatibility). In addition, responses typically produce perceivable effects on the environment. If they do so in a predictable way, responses are faster if they produce a (e.g., spatially) compatible effect on the same side than on the other side. That it, a left response is produced faster if it results predictably in a left effect than in a right effect. This effect is called response-effect (R-E) compatibility. Finally, compatibility could also exist between stimuli and the effects, which is accordingly called stimulus-effect (S-E) compatibility. Such compatibility phenomena are also relevant for applied purposes, be it in laparoscopic surgery or aviation. The present study investigates Simon and R-E compatibility for touchless gesture interactions. In line with a recent study, no effect of R-E compatibility was observed, yet irrelevant stimulus location yielded a large Simon effect. Touchless gestures thus seem to behave differently with regard to compatibility phenomena than interactions via (other) tools such as levers.

Longitudinal Effects of Breast Cancer Treatment on Neural Correlates of Attention.

OBJECTIVE: Cognitive dysfunction has been observed consistently in a subset of breast cancer survivors. Yet, the precise physiological and processing origins of dysfunction remain unknown. The current study examined the utility of methods and procedures based on cognitive neuroscience to study cognitive change associated with cancer and cancer treatment. METHODS: We used electroencephalogram and behavioral measures in a longitudinal design to investigate pre- versus post-treatment effects on attention performance in breast cancer patients (n = 15) compared with healthy controls (n = 24), as participants completed the revised Attention Network Test, a cognitive measure of alerting, orienting, and inhibitory control of attention. RESULTS: We found no group differences in behavioral performance from pretest to posttest, but significant event-related potential effects of cancer treatment in processing cue validity: After treatment, patients revealed decreased N1 amplitude and increased P3 amplitude, suggesting a suppressed early (N1) response and an exaggerated late (P3) response to invalid cues. CONCLUSIONS: The results suggest that treatment-related attentional disruption begins in early sensory/perceptual processing and extends to compensatory top-down executive processes.

Fronto-parietal alpha ERD and visuo-spatial attention in pregnant women.

Many pregnant women report impairments in their attentional capacities. However, comparative studies between pregnant and non-pregnant women using standardised attention paradigms are rare and inconsistent. During attention tasks alpha activity is known to suppress irrelevant sensory inputs and previous studies show that a large event-related desynchronisation (ERD) in the alpha range prior to target-onset predicts enhanced attentional processing. We quantified the relationship between performance (accuracy, response time) in a standardised visuo-spatial attention task and alpha ERD (∼6-12 Hz) as well as saliva estradiol level in fifteen pregnant women (M = 26.6, SD = 3.0 years) compared to fifteen non-pregnant, naturally cycling women (M = 23.1, SD = 4.3 years). Compared to non-pregnant women, alpha frequency was increased in pregnant women. Furthermore, pregnant women showed a greater magnitude of the alpha ERD prior to target-onset and a moderate increase in accuracy compared to non-pregnant women. In addition, accuracy correlated negatively with estradiol in pregnant women as well as with frontal alpha ERD in all women. These correlational findings indicate that pregnancy-related enhancement in alpha desynchronisation in a fronto-parietal network might modulate accuracy during a visuo-spatial attention task.

The Neural Signature of Impaired Inhibitory Control in Individuals with Heroin Use Disorder.

Heroin addiction imposes a devastating toll on society, with little known about its neurobiology. Excessive salience attribution to drug over nondrug cues/reinforcers, with concomitant inhibitory control decreases, are common mechanisms underlying drug addiction. Although inhibitory control alterations generally culminate in prefrontal cortex (PFC) hypoactivations across drugs of abuse, patterns in individuals with heroin addiction (iHUDs) remain unknown. We used a stop-signal fMRI task designed to meet recent consensus guidelines in mapping inhibitory control in 41 iHUDs and 24 age- and sex-matched healthy controls (HCs). Despite group similarities in the stop-signal response time (SSRT; the classic inhibitory control measure), compared with HCs, iHUDs exhibited impaired target detection sensitivity (proportion of hits in go vs false alarms in stop trials; p = 0.003). Additionally, iHUDs exhibited lower right anterior PFC (aPFC) and dorsolateral PFC (dlPFC) activity during successful versus failed stops (the hallmark inhibitory control contrast). Lower left dlPFC/supplementary motor area (SMA) activity was associated with slower SSRT specifically in iHUDs and lower left aPFC activity with worse target sensitivity across all participants (p < 0.05 corrected). Importantly, in iHUDs, lower left SMA and aPFC activity during inhibitory control was associated with shorter time since last use and higher severity of dependence, respectively (p < 0.05 corrected). Together, results revealed lower perceptual sensitivity and hypoactivations during inhibitory control in cognitive control regions (e.g., aPFC, dlPFC, SMA) as associated with task performance and heroin use severity measures in iHUDs. Such neurobehavioral inhibitory control deficits may contribute to self-control lapses in heroin addiction, constituting targets for prevention and intervention efforts to enhance recovery.SIGNIFICANCE STATEMENT Heroin addiction continues its deadly impact, with little known about the neurobiology of this disorder. Although behavioral and prefrontal cortical impairments in inhibitory control characterize addiction across drugs of abuse, these patterns remain underexplored in heroin addiction. Here, we illustrate a significant behavioral impairment in target discrimination in individuals with heroin addiction compared with matched healthy controls. We further show lower engagement during inhibitory control in the anterior and dorsolateral prefrontal cortex (key regions that regulate cognitive control) as associated with slower stopping, worse discrimination, and heroin use measures. Mapping the neurobiology of inhibitory control in heroin addiction for the first time, we identify potential treatment targets inclusive of prefrontal cortex-mediated cognitive control amenable for neuromodulation en route to recovery.

Variability of Reaction Time as a Marker of Executive Function Impairments in Fibromyalgia.

In addition to chronic widespread pain and depression and anxiety symptoms, patients with fibromyalgia frequently experience cognitive problems. This study investigated executive functions in fibromyalgia via a Go/No-Go task. To obtain comprehensive information about performance, traditional and ex-Gaussian parameters of reaction time (RT) variability were used, in addition to speed and accuracy indices. Ex-Gaussian parameters show an excellent fit to empirical RT distributions. Fifty-two female fibromyalgia patients and twenty-eight healthy controls participated. The task included 60 visual stimuli, which participants had to respond to (Go stimuli) or withhold the response to (No-Go stimuli). After 30 trials, the task rule changed, such that previous No-Go stimuli had to be responded to. Performance was indexed by the hit rate, false alarm rate, and mean (M) and intraindividual standard deviation (SD) of RT and the ex-Gaussian parameters mu, sigma, and tau. Mu and sigma indicate the M and SD of the Gaussian distribution; tau reflects the M and SD of the exponential function. Patients exhibited a lower hit rate, higher M RT, and higher tau than controls. Moreover, patients showed greater decrease of the hit rate after the change of task rule. In the entire sample, SD, sigma, and tau were inversely associated with the hit rate and positively associated with the false alarm rate. While the greater decline in hit rate after the change in task rule indicates deficient cognitive flexibility, the lack of any difference in false alarm rate suggests intact response inhibition. Higher M RT reflects reduced cognitive or motor speed. Increased tau in fibromyalgia indicates greater fluctuations in executive control and more frequent temporary lapses of attention. For the first time, this study demonstrated that indices of RT variability, in particular those derived from the ex-Gaussian function, may complement speed and accuracy parameters in the assessment of executive function impairments in fibromyalgia. Optimized assessment may facilitate the personalization of therapies aimed at improving the cognitive function of those with the disorder.

Temporally and functionally distinct large-scale brain network dynamics supporting task switching.

OBJECTIVE: Our daily activities require frequent switches among competing responses at the millisecond time scale. We determined the spatiotemporal characteristics and functional significance of rapid, large-scale brain network dynamics during task switching. METHODS: This cross-sectional study investigated patients with drug-resistant focal epilepsy who played a Lumosity cognitive flexibility training game during intracranial electroencephalography (iEEG) recording. According to a given task rule, unpredictably switching across trials, participants had to swipe the screen in the direction the stimulus was pointing or moving. Using this data, we described the spatiotemporal characteristics of iEEG high-gamma augmentation occurring more intensely during switch than repeat trials, unattributable to the effect of task rule (pointing or moving), within-stimulus congruence (the direction of stimulus pointing and moving was same or different in a given trial), or accuracy of an immediately preceding response. Diffusion-weighted imaging (DWI) tractography determined whether distant cortical regions showing enhanced activation during task switch trials were directly connected by white matter tracts. Trial-by-trial iEEG analysis deduced whether the intensity of task switch-related high-gamma augmentation was altered through practice and whether high-gamma amplitude predicted the accuracy of an upcoming response among switch trials. RESULTS: The average number of completed trials during five-minute gameplay was 221.4 per patient (range: 171-285). Task switch trials increased the response times, whereas later trials reduced them. Analysis of iEEG signals sampled from 860 brain sites effectively elucidated the distinct spatiotemporal characteristics of task switch, task rule, and post-error-specific high-gamma modulations. Post-cue, task switch-related high-gamma augmentation was initiated in the right calcarine cortex after 260 ms, right precuneus after 330 ms, right entorhinal after 420 ms, and bilateral anterior middle-frontal gyri after 450 ms. DWI tractography successfully showed the presence of direct white matter tracts connecting the right visual areas to the precuneus and anterior middle-frontal regions but not between the right precuneus and anterior middle-frontal regions. Task-related high-gamma amplitudes in later trials were reduced in the calcarine, entorhinal and anterior middle-frontal regions, but increased in the precuneus. Functionally, enhanced post-cue precuneus high-gamma augmentation improved the accuracy of subsequent responses among switch trials. CONCLUSIONS: Our multimodal analysis uncovered two temporally and functionally distinct network dynamics supporting task switching. High-gamma augmentation in the visual-precuneus pathway may reflect the neural process facilitating an attentional shift to a given updated task rule. High-gamma activity in the visual-dorsolateral prefrontal pathway, rapidly reduced through practice, may reflect the cost of executing appropriate stimulus-response translation.

Long latency responses in tongue muscle elicited by various stimulation sites in anesthetized humans - New insights into tongue-related brainstem reflexes.

BACKGROUND: Long Latency Responses (LLR) in tongue muscles are a scarcely described phenomenon, the physiology of which is uncertain. OBJECTIVES: The aim of this exploratory, observational study was to describe tongue-LLR elicited by direct trigeminal nerve (DTNS), dorsal column (DoColS), transcranial electric (TES) and peripheral median nerve (MNS) stimulation in a total of 93 patients undergoing neurosurgical procedures under general anesthesia. METHODS: Bilateral tongue responses were derived concurrently after each of the following stimulations: (1) DTNS applied with single monophasic or train-of-three pulses, ≤5 mA; (2) DoColS applied with a train-of-three pulses, ≤10 mA; (3) TES consisting of an anodal train-of-five stimulation, ≤250 mA; (4) MNS at wrist consisting of single or train-of-three monophasic pulses, ≤50 mA. Polyphasic tongue muscle responses exceeding the latencies of tongue compound muscle action potentials or motor evoked potentials were classified as LLR. RESULTS: Tongue-LLR were evoked from all stimulation sites, with latencies as follows: (1) DTNS: solely ipsilateral 20.2 ± 3.3 msec; (2) DoColS: ipsilateral 25.9 ± 1.6 msec, contralateral 25.1 ± 4.2 msec; (3) TES: contralateral 55.3 ± 10.2 msec, ipsilateral 54.9 ± 12.0 msec; (4) MNS: ipsilateral 37.8 ± 4.7 msec and contralateral 40.3 ± 3.5 msec. CONCLUSION: The tongue muscles are a common efferent in brainstem pathways targeted by trigeminal and cervical sensory fibers. DTNS can elicit the "trigemino-hypoglossal-reflex". For the MNS elicited tongue-LLR, we propose the term "somatosensory-evoked tongue-reflex". Although the origin of the TES related tongue-LLR remains unclear, these data will help to interpret intraoperative tongue recordings.

Impaired cognitive control in patients with brain tumors.

Though the assessment of cognitive functions is proven to be a reliable prognostic indicator in patients with brain tumors, some of these functions, such as cognitive control, are still rarely investigated. The objective of this study was to examine proactive and reactive control functions in patients with focal brain tumors and to identify lesioned brain areas more at "risk" for developing impairment of these functions. To this end, a group of twenty-two patients, candidate to surgery, were tested with an AX-CPT task and a Stroop task, along with a clinical neuropsychological assessment, and their performance was compared to that of a well-matched healthy control group. Although overall accuracy and response times were similar for patients and control groups, the patient group failed more on the BX trials of the AX-CPT task and on the incongruent trials of the Stroop task, specifically. Behavioral results were associated with the damaged brain areas, mostly distributed in right frontal regions, by means of a lesion-symptom mapping multivariate approach. This analysis showed that a white matter cluster in the right prefrontal area was associated with lower d'-context values on the AX-CPT, which reflected the fact that these patients rely more on later information (reactive processes) to respond to unexpected and conflicting stimuli, than on earlier contextual cues (proactive processes). Taken together, these results suggest that patients with brain tumors present an imbalance between proactive and reactive control strategies in high interfering conditions, in association with right prefrontal white matter lesions.

A test of the unified model of vision and attention: Effects of parietal-occipital damage on visual orienting.

Visual orienting was studied in a patient (FM) with parietal-occipital damage due to oligodendroglioma and associated surgery, and in eighteen control participants. The ability of FM and control participants to shift attention in response to spatial landmark cues, and in response to cues that recruit endogenous orienting via encoding of cue identity, were assessed. According to the unified model of vision and attention (Lambert, A. et al., Journal of Experimental Psychology: Human Perception & Performance, 44, 412-432) FM should find it difficult to orient attention in response to spatial landmarks due to impaired functioning of the dorsal visual stream; but shifting attention in response to cue identity, encoded via the ventral visual stream, should be spared. Consistent with these predictions, FM was unable to shift attention in the landmark cueing task, but shifted attention effectively in response to identity cues; and her visual orienting performance differed reliably from controls. These findings complement our earlier observation of preserved orienting towards landmark cues in a patient with bilateral damage to the ventral visual stream, and add to a growing body of evidence in support of the unified model of vision and attention.

Can arrows change the subjective perception of space? Exploring symbolic attention repulsion.

The attention repulsion effect (ARE) refers to distortions in the perception of space for areas near the focus of attention. For instance, when attending to the right-hand side of the visual field, objects in central vision may appear as though they are shifted to the left. The phenomenon is likely caused by changes in visual cell functioning. To date, research on the ARE has almost exclusively used exogenous manipulations of attention. In contrast, research exploring endogenous attention repulsion has been mixed, and no research has explored the effects of nonpredictive arrow cues on this phenomenon. This gap in the literature is unexpected, as symbolic attention appears to be a unique form of attentional orienting compared with endogenous and exogenous attention. Therefore, this study explored the effects of symbolic orienting on spatial repulsion and compared it with an exogenously generated ARE. Across four experiments, both exogenous and symbolic orienting resulted in AREs; however, the magnitude of the symbolic ARE was smaller than the exogenous ARE. This difference in magnitude persisted, even after testing both phenomena using stimulus timing parameters known to produce optimal effects in traditional attentional cueing paradigms. Therefore, compared with symbolic attention, it appears that exogenous manipulations may tightly constrict attention resources on the cued location, in turn, potentially influencing the functioning of visual cells for enhanced perceptual processing.

Dorsal visual stream is preferentially engaged during externally guided action selection in Parkinson Disease.

OBJECTIVE: In patients with Parkinson Disease (PD), self-initiated or internally cued (IC) actions are thought to be compromised by the disease process, as exemplified by impairments in action initiation. In contrast, externally-cued (EC) actions which are made in response to sensory prompts can restore a remarkable degree of movement capability in PD, particularly alleviating freezing-of-gait. This study investigates the electrophysiological underpinnings of movement facilitation in PD through visuospatial cuing, with particular attention to the dynamics within the posterior parietal cortex (PPC) and lateral premotor cortex (LPMC) axis of the dorsal visual stream. METHODS: Invasive cortical recordings over the PPC and LPMC were obtained during deep brain stimulation lead implantation surgery. Thirteen PD subjects performed an action selection task, which was constituted by left or right joystick movement with directional visual cuing in the EC condition and internally generated direction selection in the IC condition. Time-resolved neural activities within and between the PPC and LPMC were compared between EC and IC conditions. RESULTS: Reaction times (RT) were significantly faster in the EC condition relative to the IC condition (paired t-test, p = 0.0015). PPC-LPMC inter-site phase synchrony within the ß-band (13-35 Hz) was significantly greater in the EC relative to the IC condition. Greater PPC-LPMC ß debiased phase lag index (dwPLI) prior to movement onset was correlated with faster reaction times only in the EC condition. Multivariate granger causality (GC) was greater in the EC condition relative to the IC condition, prior to and during movement. CONCLUSION: Relative to IC actions, we report relative increase in inter-site phase synchrony and directional PPC to LPMC connectivity in the ß-band during preparation and execution of EC actions. Furthermore, increased strength of connectivity is predictive of faster RT, which are pathologically slow in PD patients. Stronger engagement of the PPC-LPMC cortical network by an EC specifically through the channel of ß-modulation is implicated in correcting the pathological slowing of action initiation seen in Parkinson's patients. SIGNIFICANCE: These findings shed light on the electrophysiological mechanisms that underlie motor facilitation in PD patients through visuospatial cuing.

Neural Signatures of Interface Errors in Remote Agent Manipulation.

The manipulation of remote agents such as robotic arms in remote surgery or in BCI-wheelchair control are prone to errors. Some of these are related to user intent misclassification or other interface system errors, which lead to an incorrect movement. Here we focused on errors originating from unpredicted interface movements violating user intent and producing sensory conflicts. In addition, we examined effects of incongruent/congruent sensory stimuli induced by interface errors, focusing on haptic and visual cues in the system. The overarching goal was to identify the prototypical patterns of electroencephalogram (EEG) error signals associated with two types of interface errors rising when the visual and proprioceptive feedback are congruent or incongruent. For purposes of comparison validity, both types of errors were recorded in the same 3D virtual game environment. The comparison of congruent and incongruent interface errors revealed significant and marginally significant differences in EEG potentials with respect to profile, latencies, scalp distribution and sources. Different EEG time-frequency combinations had high power content. Incongruence between visual and proprioceptive feedback in interface errors not only elicited distinct EEG signal characteristics, but also produced a marginally significant Stroop effect. Incongruency in visuo-haptic feedback modalities cause a delayed user response. This effect is of major importance for the design of controlling interfaces and can provide designers with crucial information when aiming to control human response time.

Adaptation of a semantic picture-word interference paradigm for future language mapping with transcranial magnetic stimulation: A behavioural study.

Neuro-navigated transcranial magnetic stimulation (TMS) helps to identify language-related cortical regions prior to brain tumour surgery. We adapted a semantic picture-word interference (PWI) paradigm from psycholinguistics to high-resolution TMS language mapping which prospectively can be used to specifically address the level of semantic processing. In PWI, pictures are presented along with distractor words which facilitate or inhibit the lexical access to the picture name. These modulatory effects of distractors can be annihilated in language-sensitive areas by the inhibitory effects of TMS on language processing. The rationale here is to observe the distractor effect without active stimulation and then to observe presumably its elimination by interference of the TMS stimulation. The special requirements to use PWI in this setting are (1) identifying word material for accelerating reliably naming latencies, choosing (2) the ideal presentation modality, and (3) the appropriate timing of distractor presentation. These are then controlled in real TMS language mapping. To adapt a semantic PWI naming paradigm for TMS application we employed 30 object-pictures in spoken German language. Part-whole associative semantic related or unrelated distractors were presented in two experiments including 15 healthy volunteers each, once auditorily and once visually. Data analysis across the entire stimulus set revealed a trend for facilitation in the visual condition, whereas no effects were observed for auditory distractors. In a sub-set, we found a significant facilitation effect for visual semantic distractors. Thus, with this study we provide a well-controlled item set for future studies implementing effective TMS language mapping applying visual semantic PWI.

Bilateral cataract surgery improves neurologic brake reaction time and stopping distance in elderly drivers.

AIMS: To determine brake reaction times before and after bilateral cataract surgery in elderly drivers. METHODS: Sixty-four patients were evaluated on the day of and 4 weeks after bilateral cataract surgery. Forty-three healthy individuals with a valid driving licence served as the control group. A driving simulator was used to determine brake reaction times after receiving a visual stimulus. Total brake reaction time (BRT) as well as neurologic reaction time (NRT), foot transfer time (FTT) and brake pedal travel time (BPTT) were measured, and the measurements obtained before and after cataract surgery were compared. The correlations between NRT, best-corrected visual acuity (BCVA) and contrast sensitivity (CS) were assessed. RESULTS: Out of the 64 patients with bilateral cataract, 53 were assessed for postsurgical measurements. All time measures improved significantly after cataract surgery (BRT, 815.7(224) versus 647.9(148) ms; NRT, 364.7(91) versus 283.5(44) ms; FTT, 290.8(62) versus 248.6(58) ms; and BPTT, 160.6(96) versus 116.6(72) ms, p < 0.001). The calculated stopping distance improved significantly after surgery (22.3(6) versus 19.9(4) m at 50 km/h). Best-corrected visual acuity (BCVA) and contrast sensitivity (CS) improved significantly after surgery (0.25(0.2) versus 0.05(0.05), n = 53, p < 0.001; 1.4(0.2) versus 1.6(0.1), p < 0.001, respectively). There was a significant negative correlation between CS and NRT before surgery (r = -0.253, n = 64, p = 0.04, Pearson's correlation). CONCLUSION: Our findings show a significant effect of CS on neurological BRTs and the corresponding stopping distances. This highlights the importance of presurgical CS evaluation as a critical factor in cataract surgery decisions in elderly drivers.

P50 inhibition defects with psychopathology and cognitive impairment in patients with first-episode drug naïve schizophrenia.

BACKGROUND: Many studies have announced that P50 inhibition defects represent sensory gating deficits in schizophrenia, but studies seldom have searched the correlation between P50 inhibition defects and the psychopathology or cognitive impairment of patients with first-episode, drug naïve (FEDN) of schizophrenia. In this study, we investigated the auditory sensory gating deficits in a large number of Han patients with FEDN schizophrenia and their correlation with clinical symptoms and cognitive impairment. METHODS: A total of 130 patients with FEDN schizophrenia and 189 healthy controls were recruited in this study. Positive and Negative Syndrome Scale (PANSS) and its five-factor model were used to score the psychopathology of the patients, and P50 inhibition was recorded using the 64-channel electroencephalography (EEG) system. RESULTS: Patients exhibited significantly longer S1 and S2 latency, lower S1 and S2 amplitudes and lower P50 difference than healthy controls (all p < 0.05). Significant correlations existed between S1 latency and PANSS negative symptoms or cognitive factor, P50 ratio and general psychopathology, P50 ratio and PANSS total score, P50 difference and general psychopathology, and P50 difference and PANSS total score (all p < 0.05). Multiple regression analysis revealed that S1 latency, sex, age, and education were contributors to negative symptom score (all p < 0.05). S1 latency, S2 latency, sex, age, and smoking status were contributors to cognitive factor (all p < 0.05). CONCLUSIONS: Our results show that patients with FEDN schizophrenia have P50 inhibition defects, which may be related to their psychopathological symptoms and cognitive impairment.

Return to Driving After Foot and Ankle Surgery: A Novel Survey to Predict Passing Brake Reaction Time.

Introduction. Brake reaction time (BRT) is an accepted method for establishing recommendations for safe return to driving by the National Highway Traffic Safety Administration. Other than performing a BRT test in clinic, there is no established clinical tool to help physicians differentiate safe from unsafe drivers once patients reach general recovery milestones. The purpose is to present individual recommendations to the patient through a novel, validated survey evaluating safe return to driving after orthopaedic surgery of the right foot and ankle. Methods. A total of 171 patients undergoing 1 of 3 specific foot and ankle procedures were prospectively enrolled. A 4-question survey and BRT were completed 6 weeks postoperatively. The following questions were asked: (1) "I think my brake reaction time is slower than most drivers my age," (2) "I think my brake reaction time is faster than most drivers my age," (3) "I think my brake reaction time is about the same as most drivers my age," (4) "Based on what I think my brake reaction time is, I think I am ready to drive." Internal consistency was determined with Cronbach's α and item total correlation. External validity was determined by Spearman's correlation coefficient. A BRT less than 0.850 s was considered as a pass. Results. Of 171 patients, 162 (95%) with ages ranging from 21 to 83 years achieved a passing BRT by 7.6 weeks. After removing 1 question because of internal inconsistency, the optimal threshold for predicting passing BRT was 10/15 points or higher, which had 99% probability of success that a patient would pass the BRT (95% CI = 96%, 100%). Conclusion. This novel, 3-question driving readiness survey can accurately predict a passing BRT Achilles rupture repair, total ankle arthroplasty, and hallux valgus correction performed in the right foot and ankle as early as 6 weeks postoperatively.Level of Evidence: Level II: Comparative study.

The Dynamics of Language Network Interactions in Lexical Selection: An Intracranial EEG Study.

Speaking in sentences requires selection from contextually determined lexical representations. Although posterior temporal cortex (PTC) and Broca's areas play important roles in storage and selection, respectively, of lexical representations, there has been no direct evidence for physiological interactions between these areas on time scales typical of lexical selection. Using intracranial recordings of cortical population activity indexed by high-gamma power (70-150 Hz) modulations, we studied the causal dynamics of cortical language networks while epilepsy surgery patients performed a sentence completion task in which the number of potential lexical responses was systematically varied. Prior to completion of sentences with more response possibilities, Broca's area was not only more active, but also exhibited more local network interactions with and greater top-down influences on PTC, consistent with activation of, and competition between, more lexical representations. These findings provide the most direct experimental support yet for network dynamics playing a role in lexical selection among competing alternatives during speech production.