Can post-error dynamics explain sequential reaction time patterns?

The role of lateral prefrontal cortex (LPFC) in speech monitoring has not been delineated. Recent work suggests that medial frontal cortex (MFC) is involved in overt speech monitoring initiated before auditory feedback. This mechanism is reflected in an event-related potential (ERP), the error negativity (Ne), peaking within 100 ms after vocal-onset. Critically, in healthy individuals the Ne is sensitive to the accuracy of the response; it is larger for error than correct trials. By contrast, patients with LPFC damage are impaired in non-verbal monitoring tasks showing no amplitude difference between the Ne measured in correct vs. error trials. Interactions between the LPFC and the MFC are assumed to play a necessary role for normal action monitoring. We investigated whether the LPFC was involved in speech monitoring to the same extent as in non-linguistic actions by comparing performance and EEG activity in patients with LPFC damage and in aged-matched controls performing linguistic (Picture Naming) and non-linguistic (Simon) tasks. Controls did not produce enough errors to allow the comparison of the Ne or other ERP in error vs. correct trials. PFC patients had worse performance than controls in both tasks, but their Ne was larger for error than correct trials only in Naming. This task-dependent pattern can be explained by LPFC-dependent working-memory requirements present in non-linguistic tasks used to study action monitoring but absent in picture naming. This suggests that LPFC may not be necessary for speech monitoring as assessed by simple picture naming. In addition, bilateral temporal cortex activity starting before and peaking around vocal-onset was observed in LPFC and control groups in both tasks but was larger for error than correct trials only in Naming, suggesting the temporal cortex is associated with on-line monitoring of speech specifically when access to lexical representations is necessary.

Representation of Spatial Goals in Rat Orbitofrontal Cortex

Recurrent networks endowed with structural priors explain suboptimal animal behavior

The aim of this investigation was to analyze the reaction time (RT) of finswimmers who competed in the 11th Asia Finswimming Championships. A total of 96 male and female finswimmers were used as subjects. An Omega timing system was used to record the reaction time and the final performance time of the finswimmers. The mean reaction time was found to be shorter in male finswimmers than in female finswimmers (p＜0.05); shorter reaction times were also found in short-distance than in long-distance male finswimmers (p＜0.05). Also, significant positive correlations were only found in 100 meter surface and 50 meter apnea finswimming events in male finswimmers (p＜0.05), not for all other male and female finswimming events. As predicted, male finswimmers and short-distance finswimmers had fast RT, whether due to training or to inherent ability. A pre-test of RT may help with the selection of the type of event best suited for each individual finswimmer. In most cases, the correlation between RT and final time (FT) was not significant. Therefore, the quality of the strokes is still the main factors for final achievement. Finswimmers with slower RT may work on their muscle strengths and techniques to compensate for a slower RT.

Reversal Learning as a Neuropsychological Indicator for the Neuropathology of Obsessive Compulsive Disorder? A Behavioral Study

Introduction Few reports have examined how pre-sleep alcohol affects performance on the next day given adequate sleep opportunity on a preferred schedule. Our goal is to identify whether alcohol intake targeting .08g% 1 hr before sleep of ~8 h will affect PVT performance on subsequent days, with the hypothesis that morning performance will be negatively affected. Methods 25 adults (13F; age range 22-57 y) completed the full study, including at-home sleep on a fixed schedule of 8-9 hr and two 3-night in-lab PSG sessions spaced ≥3 days apart. Sessions were counterbalanced for alcoholic or nonalcoholic control beverage administered in 3 drinks over 45 minutes ending 1 hr before bedtime. Alcohol was targeted to .08g%. The 10-min PVT (Ambulatory Monitoring, Inc.) was given each night (PM-Lab) 1.5 hr before drinking and in the morning after a light breakfast (AM-Lab) 50 min after waking. PVT was performed at home/work twice each day within 1.5-h windows starting 3h after waking (AM-Home) and 7.5h after waking (PM-Home). Two reaction time (RT) variables were assessed: RRT (1/RT), FRT (10% fastest RT). Linear mixed effects models were used to account for nesting of assessments within alcohol/control condition and days. Results RRTs showed slowed RT (meanRT±SE) following alcohol: AM-Lab F=7.234, p=.008, alcohol RT=246±9.6 msec, control RT=234±9.6 msec; AM-Home F=17.936, p<.001, alcohol RT=254±9.5 msec, control RT=242±9.6 msec; but not PM-Home or PM-Lab tests. FRT slowed for AM-Lab F=9.391, p=.003, alcohol FRT=195±4.3 msec, control FRT=201±4.3 msec; AM-Home F=17.251, p=.001, alcohol FRT= 202±4.4 msec, control FRT=194±4.4 msec; PM-Home F=3.379, p=.068 (trend), alcohol FR=200±4.8 msec, control FRT=196±4.8 msec, but not for PM-Lab PVTs. PM-Home FRT also had a significant day order effect: F=3.087, p=.0496, Day 1 FRT=197±5.0 msec, Day 2 FRT=202±5.0 msec, Day 3 FRT=195±5.0 msec. Conclusion We found statistically significant slowing of psychomotor vigilance RT on days after pre-sleep alcohol lasting up to 3-4.5h after waking in the morning (with a trend up to 7.5-9h post waking). PVT lapses (not shown) were similarly affected by alcohol. Thus, even with sufficient sleep opportunity, RT is impaired following 3 consecutive nights of alcohol drinking. Support (if any) R01AA025593

Decision Making in Recurrent Neuronal Circuits

1. Earlier studies have shown that changes in the difficulty of sensory discrimination in a choice reaction time task result in a prolongation of the peak latency for several components of the long-latency event-related potential (ERP). With the use of the technique of response-locked averaging, we have previously shown that manipulation of the difficulty of sensory discrimination also affects response execution as assessed by the interval between the ERP and onset of the response. In the present paper we examine the hypothesis that changing the compatibility of the responses may also affect the difficulty of the discrimination, as well as the execution of the response, as assessed by the interval between stimulus onset and the ERP. Such an effect of response compatibility would provide further evidence for the close integration of motor and sensory processes in the performance of choice reaction time tasks. 2. We continuously recorded the electroencephalogram (EEG) from the scalp and the electromyogram (EMG) from the responding muscles in both compatible and noncompatible visual choice reaction time tasks. In the compatible task subjects responded to a lateralized visual stimulus with the hand ipsilateral to the stimulus, whereas in the noncompatible task they responded with the contralateral hand. EEG and EMG responses were analyzed and averaged off-line, aligning the waveforms by either stimulus onset (stimulus-synchronized averages) or response onset (response-synchronized averages), and averaged separately for both correct and incorrect response outcomes. 3. Response times were significantly faster for frequent stimuli than rare stimuli and were significantly faster to rare stimuli in the compatible than the noncompatible condition. In responses to the frequent stimuli (where both hands were required to respond), the right hand was slightly but consistently faster than the left hand. The right hand also accounted for 83% of the errors made. 4. Stimulus-synchronized and response-synchronized ERPs to either frequent or rare stimuli had a similar appearance for correct responses in both the compatible and noncompatible conditions. The coupling of the response to the ERP for the rare stimuli, however, was different for the two conditions: the response occurred later relative to the ERP components in the response-synchronized average in the noncompatible condition compared with the compatible condition. By contrast, the coupling of the ERPs to the onset of the stimulus was the same in the two conditions. 5. Stimulus-synchronized averages for error responses in which the rare tone was mistaken for a frequent tone showed early sensory processing (as judged by the ERPs) that was similar to that of correct responses to the rare stimuli. After the apparent positive (P2) component of the cerebral response, however, the processing differed, with a superimposed broad negativity possibly reflecting awareness by the subject that a mistake had been made. By contrast, the response-synchronized averages for these error trials appeared like those to frequent stimuli, with the response being coupled to the P2 component of the cerebral response. 6. These results suggest that response compatibility affects response selection processes but does not alter sensory discrimination. However, despite the similarly tight coupling of the response to the ERP in both the compatible and noncompatible conditions, the response occurred later relative to the ERPs in the noncompatible condition. This suggests that different components of the ERP are responsible for triggering the response in different circumstances. Our observations on the error trials suggests that the decision to respond (on these trials) is based on the occurrence of cerebral events that are evoked by either rare or frequent stimuli, whereas this decision (on correct response trials) is based on cerebral events elicited only by the rare stimuli.

Objective:To determine the impact of cognitive interference on foot pedal reaction time among stroke survivors with right- (RH) or left-hemiplegia (LH).Design:Cross-sectional comparison without randomization.Subjects/patients:10 patients post-stroke with RH, 10 with LH; 10 age-matched controls.Methods:Foot pedal response times were measured using three different reaction time (RT) paradigms: simple RT, dual-task RT (counting backward by serial 3 seconds), and choice RT (correct response contingent on stimuli to eliminate pre-programing). RH and LH used the non-paretic leg for all trials. Three 3 (RT task) × 3 (group) mixed-model factorial ANOVAs were used to compare RT, movement time (MT), total response time (TRT).Results:Overall controls demonstrated faster RT than RH (332 ± 73 versus 474 ± 144 ms, P < 0.001) or LH (402 ± 127 ms, P < 0.05); LH group demonstrated faster RT than those with RH (P < 0.05). Control subjects demonstrated significantly faster RT than RH for all RT conditions (P < 0.05 for all). In contrast, controls achieved significantly faster RT than LH for the choice RT condition only (P < 0.05), but not for the simple (P = 0.12) or dual-task RT conditions (P = 0.25).Conclusions:Compared to controls, response time was significantly impaired among LH and RH when the response could not be pre-programmed. While current simple RT testing commonly employed by driver rehab specialists may be sufficient for detecting RT deficits in patients with RH, simple or dual-task RT tests alone may fail to detect RT deficiencies among LH, even when testing the non-paretic limb. Choice RT should be added to post-stroke driver fitness assessment, particularly for patients with LH.

Performance of memory tasks is impaired by lesions to either the medial prefrontal cortex (mPFC) or the hippocampus (HPC); although how these two areas contribute to successful performance is not well understood. mPFC unit activity is temporally affected by hippocampal-theta oscillations, with almost half the mPFC population entrained to theta in behaving animals, pointing to theta interactions as the mechanism enabling collaborations between these two areas. mPFC neurons respond to sensory stimuli and responses in working memory tasks, though the function of these correlated firing rate changes remains unclear because similar responses are reported during mPFC dependent and independent tasks. Using a DNMS task we compared error trials vs. correct trials and found almost all mPFC cells fired at similar rates during both error and correct trials (92%), however theta-entrainment of mPFC neurons declined during error performance as only 17% of cells were theta-entrained (during correct trials 46% of the population was theta-entrained). Across the population, error and correct trials did not differ in firing rate, but theta-entrainment was impaired. Periods of theta-entrainment and firing rate changes appeared to be independent variables, and only theta-entrainment was correlated with successful performance, indicating mPFC-HPC theta-range interactions are the key to successful DNMS performance.

The aim of this study was to identify factors that might affect reaction-time (RT) testing and interpretation. Simple reaction time and choice reaction time were measured in a cohort of 893 white young men. Age, body size, color vision, and intelligence (IQ) were analyzed as subject-related factors. Effects of time of day of test and different examiners were analyzed in relation to testing facilities. All factors were statistically correlated to RTs; however, the relationships between age and RTs and between height and RTs were noticeably weak and apparently insignificant in practice. A defect in color vision was notably associated with slow choice RT and with mistakes on the test. As the choice was coded by color in the choice RT test, the result was expected. Low IQs were significantly related with slow RTs. Slow RTs have been correlated with low-grade IQs in previous studies also. Lower grades and greater variation in RTs were recorded just before meals or if testing was done outside the daily testing schedule. The examiner supervising the RT testing significantly affected the results. It was concluded that the introduction for tests should be given impersonally using a tape recorder or comparable equipment.

Greater cognitive ability in childhood is associated with increased longevity, and speedier reaction time (RT) might account for much of this linkage. Greater bodily symmetry is linked to both higher cognitive test scores and faster RTs. It is possible, then, that differences in bodily system integrity indexed by symmetry may underlie the associations of RT and intelligence with increased longevity. However, RT and symmetry have seldom been examined in the same study, and never in children. Here, in 2 large samples aged 4 to 15 (combined n = 856), we found that more symmetrical children had significantly faster mean choice RT and less variability in RT. These associations of faster and less variable RT with greater symmetry early in life raise the possibility that the determinants of longevity in part originate in processes influencing bodily system integrity early in the life-course.

One of the most important clinical features of psychopaths is their differential emotional response style. The present study examined the modulating effect of negative mood induction on the processing of emotional information and its relation to psychopathy. The sample of 105 participants were randomly assigned to two types of mood induction conditions (negative vs neutral) and viewed three types of visual stimuli (positive, neutral, negative). Psychopathic Personality Inventory‐R (PPI‐R; Lilienfeld & Andrews) was employed to measure their psychopathic traits. It was hypothesized that individuals high on PPI‐II (i.e., self‐centered impulsivity) would show greater response latencies to emotionally negative pictures when they were induced into a negative mood compared to individuals high on PPI‐I (i.e., fearless dominance). In general, individuals high on PPI‐II showed greater response latencies to emotionally negative pictures, but their responsivity did not vary as a function of mood manipulation or task demands. When controlling the influence of other PPI factors, PPI‐I predicted reaction time (RT) facilitation to positive pictures in general (i.e., faster RT), and when interacting with a negative mood induction, it predicted longer viewing time of and more difficulty disattending from positive pictures (i.e., slower RT). These results were discussed within emotional processing theory associated with psychopathy.

Mutations in the synaptic gene SHANK3 lead to a neurodevelopmental disorder known as Phelan-McDermid syndrome (PMS). PMS is a relatively common monogenic and highly penetrant cause of autism spectrum disorder (ASD) and intellectual disability (ID), and frequently presents with attention deficits. The underlying neurobiology of PMS is not fully known and pharmacological treatments for core symptoms do not exist. Here, we report the production and characterization of a Shank3-deficient rat model of PMS, with a genetic alteration similar to a human SHANK3 mutation. We show that Shank3-deficient rats exhibit impaired long-term social recognition memory and attention, and reduced synaptic plasticity in the hippocampal-medial prefrontal cortex pathway. These deficits were attenuated with oxytocin treatment. The effect of oxytocin on reversing non-social attention deficits is a particularly novel finding, and the results implicate an oxytocinergic contribution in this genetically defined subtype of ASD and ID, suggesting an individualized therapeutic approach for PMS.DOI: http://dx.doi.org/10.7554/eLife.18904.001

To provide a fundamental basis for understanding decision-making and decision confidence, we analyze a neuronal spiking attractor-based model of decision-making. The model predicts probabilistic decision-making with larger neuronal responses and larger functional magnetic resonance imaging (fMRI) blood-oxygen-level-dependent (BOLD) responses on correct than on error trials because the spiking noise-influenced decision attractor state of the network is consistent with the external evidence. Moreover, the model predicts that the neuronal activity and the BOLD response will become larger on correct trials as the discriminability ΔI increases and confidence increases and will become smaller as confidence decreases on error trials as ΔI increases. Confidence is thus an emergent property of the model. In an fMRI study of an olfactory decision-making task, we confirm these predictions for cortical areas including medial prefrontal cortex and the cingulate cortex implicated in choice decision-making, showing a linear increase in the BOLD signal with ΔI on correct trials, and a linear decrease on error trials. These effects were not found in a control area, the orbitofrontal cortex, where reward value useful for the choice is represented on a continuous scale but that is not implicated in the choice itself. This provides a unifying approach to decision-making and decision confidence and to how spiking-related noise affects choice, confidence, synaptic and neuronal activity, and fMRI signals.