Increased Response Latencies Research Articles

Performance of working memory of musicians and non-musicians in tests with letters, digits, and geometrical shapes

Background. Recent researches points out that musical training might have a positive influence on human cognitive domain and working memory improvements are thought to mediate this influence. However, there is some discrepancy among results of researches dealing with working memory testing of musicians and non-musicians. Materials and Methods. The participants were the students who for 10–15 years had been engaged in regular musical practice (musicians) and their peers who had no previous musical experience (non-musicians). A computerized working memory test for letters, digits and shapes with successive presentation of stimuli was applied in the current study. Results. Musicians and non-musicians did not differ in the overall number of mistakes and latency of responses made in all subtests for letters, digits and shapes. The left hand made significantly more mistakes than the right one in both groups, but this regularity was more typical of non-musicians. The right hand responded faster than the left one while doing all subtests in both groups, but such a motor asymmetry was more evident for nonmusicians. Musicians mostly did not demonstrate an increase in latency of responses with task complexity growing from set to set of stimuli, while non-musicians did. Conclusions. The efficiency of working memory test performance did not differ among musicians and non-musicians. Musicians have tighter interhemispheric cooperation during the memory test and that was indicated by a lesser motor asymmetry. Musicians have almost equal latency of responses regardless of task complexity, while non-musicians require more time for responding to stimuli during growing task complexity, probably because of using different search patterns in working memory or tighter interhemispheric cooperation.

Orthographic effects in spoken word recognition: Evidence from Chinese.

Extensive evidence from alphabetic languages demonstrates a role of orthography in the processing of spoken words. Because alphabetic systems explicitly code speech sounds, such effects are perhaps not surprising. However, it is less clear whether orthographic codes are involuntarily accessed from spoken words in languages with non-alphabetic systems, in which the sound-spelling correspondence is largely arbitrary. We investigated the role of orthography via a semantic relatedness judgment task: native Mandarin speakers judged whether or not spoken word pairs were related in meaning. Word pairs were either semantically related, orthographically related, or unrelated. Results showed that relatedness judgments were made faster for word pairs that were semantically related than for unrelated word pairs. Critically, orthographic overlap on semantically unrelated word pairs induced a significant increase in response latencies. These findings indicate that orthographic information is involuntarily accessed in spoken-word recognition, even in a non-alphabetic language such as Chinese.

The effects of steady swimming on fish escape performance

Escape maneuvers are essential to the survival and fitness of many animals. Escapes are frequently initiated when an animal is already in motion. This may introduce constraints that alter the escape performance. In fish, escape maneuvers and steady, body caudal fin (BCF) swimming are driven by distinct patterns of curvature of the body axis. Pre-existing muscle activity may therefore delay or diminish a response. To quantify the performance consequences of escaping in flow, escape behavior was examined in bluegill sunfish (Lepomis macrochirus) in both still-water and during steady swimming. Escapes executed during swimming were kinematically less variable than those made in still-water. Swimming escapes also had increased response latencies and lower peak velocities and accelerations than those made in still-water. Performance was also lower for escapes made up rather than down-stream, and a preference for down-stream escapes may be associated with maximizing performance. The constraints imposed by pre-existing motion and flow, therefore, have the potential to shape predator-prey interactions under field conditions by shifting the optimal strategies for both predators and prey.

Cue Utilization and Cognitive Load in Novel Task Performance.

This study was designed to examine whether differences in cue utilization were associated with differences in performance during a novel, simulated rail control task, and whether these differences reflected a reduction in cognitive load. Two experiments were conducted, the first of which involved the completion of a 20-min rail control simulation that required participants to re-route trains that periodically required a diversion. Participants with a greater level of cue utilization recorded a consistently greater response latency, consistent with a strategy that maintained accuracy, but reduced the demands on cognitive resources. In the second experiment, participants completed the rail task, during which a concurrent, secondary task was introduced. The results revealed an interaction, whereby participants with lesser levels of cue utilization recorded an increase in response latency that exceeded the response latency recorded for participants with greater levels of cue utilization. The relative consistency of response latencies for participants with greater levels of cue utilization, across all blocks, despite the imposition of a secondary task, suggested that those participants with greater levels of cue utilization had adopted a strategy that was effectively minimizing the impact of additional sources of cognitive load on their performance.

Effect of hypovolemia on efficacy of reflex maintenance of blood pressure on orthostatic challenge.

Blood volume is an important determinant of the efficacy of the negative feedback mechanisms that maintain blood pressure. However, its effect on time profile and magnitude of the responses remain unstudied. To study the effect of mild hypovolemia on time profiles and magnitude of changes in blood pressure and heart rate in healthy subjects before and after blood donation. Fifty six healthy volunteer donors who signed up for blood donation were recruited (age 35 ± 7 years; weight 75 ± 9 Kg). Baseline beat to beat blood pressure and Lead II ECG was recorded for 5 min followed by orthostatic challenge for 3 min before and after blood donation. The donation of 450 ml of blood did not lead to any changes in the resting systolic, diastolic or mean blood pressure. However, there was a significant decrease in pulse pressure after blood donation along with an increase in the heart rate. During orthostatic challenge, after blood donation there was a greater fall in systolic, diastolic, mean and pulse pressure along with a greater increase in heart rate as compared to before the blood donation. The latency to response and the total time to recovery of blood pressure and heart rate increased significantly after blood donation. Maintenance of blood pressure after orthostatic challenge is not compromised after mild hypovolemia produced by donation of 450 ml of blood. However, mild hypovolemia results in increase in latency of response and is accompanied with larger magnitude of fall in blood pressure during orthostatic challenge.

The amygdalo-nigrostriatal network is critical for an optimal temporal performance.

The amygdalo-nigrostriatal (ANS) network plays an essential role in enhanced attention to significant events. Interval timing requires attention to temporal cues. We assessed rats having a disconnected ANS network, due to contralateral lesions of the medial central nucleus of the amygdala (CEm) and dopaminergic afferents to the lateral striatum, as compared to controls (sham and ipsilateral lesions of CEm and dopaminergic afferents to LS) in a temporal bisection task. ANS disconnection induced poorer temporal precision and increased response latencies to a short duration. The present results reveal a role of the ANS network in temporal processing.

Phytochemical Screening and Antinociceptive and Antidiarrheal Activities of Hydromethanol and Petroleum Benzene Extract of Microcos paniculata Barks.

Introduction. Microcos paniculata is traditionally used for treating diarrhea, wounds, cold, fever, hepatitis, dyspepsia, and heat stroke. Objective. To investigate the qualitative phytochemical constituents of hydromethanol (HMPB) and petroleum benzene extract of Microcos paniculata barks (PBMPB) and to evaluate their antinociceptive and antidiarrheal activities. Methods. Phytochemical constituents and antinociceptive and antidiarrheal activities were determined and evaluated by different tests such as Molisch's, Fehling's, Mayer's, Wagner's, Dragendorff's, frothing, FeCl3, alkali, Pew's, and Salkowski's test, general test of glycosides, Baljet and NH4OH test, formalin-induced paw licking, acetic acid-induced writhing, tail immersion, and hot plate tests, and castor oil and MgSO4 induced diarrheal tests. Results. These extracts revealed the presence of saponins, flavonoids, and triterpenoids and significantly (⁎ P < 0.05, versus control) reduced paw licking and abdominal writhing of mice. At 30 min after their administration, PBMPB revealed significant increase in latency (⁎ P < 0.05, versus control) in tail immersion test. In hot plate test, HMPB and PBMPB 200 mg/kg showed significant increase in response latency (⁎ P < 0.05, versus control) at 30 min after their administration. Moreover, both extracts significantly (⁎ P < 0.05, versus control) inhibited percentage of diarrhea in antidiarrheal models. Conclusion. Study results indicate that M. paniculata may provide a source of plant compounds with antinociceptive and antidiarrheal activities.

The Doubting System 1: Evidence for automatic substitution sensitivity

A long prevailing view of human reasoning suggests severe limits on our ability to adhere to simple logical or mathematical prescriptions. A key position assumes these failures arise from insufficient monitoring of rapidly produced intuitions. These faulty intuitions are thought to arise from a proposed substitution process, by which reasoners unknowingly interpret more difficult questions as easier ones. Recent work, however, suggests that reasoners are not blind to this substitution process, but in fact detect that their erroneous responses are not warranted. Using the popular bat-and-ball problem, we investigated whether this substitution sensitivity arises out of an automatic System 1 process or whether it depends on the operation of an executive resource demanding System 2 process. Results showed that accuracy on the bat-and-ball problem clearly declined under cognitive load. However, both reduced response confidence and increased response latencies indicated that biased reasoners remained sensitive to their faulty responses under load. Results suggest that a crucial substitution monitoring process is not only successfully engaged, but that it automatically operates as an autonomous System 1 process. By signaling its doubt along with a biased intuition, it appears System 1 is “smarter” than traditionally assumed.

Commentary: Noradrenaline and Dopamine Neurons in the Reward/Effort Trade-off: A Direct Electrophysiological Comparison in Behaving Monkeys.

Commentary: Noradrenaline and Dopamine Neurons in the Reward/Effort Trade-off: A Direct Electrophysiological Comparison in Behaving Monkeys.

Marijuana's acute effects on cognitive bias for affective and marijuana cues.

Marijuana produces acute increases in positive subjective effects and decreased reactivity to negative affective stimuli, though may also acutely induce anxiety. Implicit attentional and evaluative processes may explicate marijuana's ability to acutely increase positive and negative emotions. This within-subjects study examined whether smoked marijuana with 2.7-3.0% delta-9-tetrahydrocannabinol (THC), relative to placebo, acutely changed attentional processing of rewarding and negative affective stimuli as well as marijuana-specific stimuli. On 2 separate days, regular marijuana users (N = 89) smoked placebo or active THC cigarette and completed subjective ratings of mood, intoxication, urge to smoke marijuana, and 2 experimental tasks: pleasantness rating (response latency and perceived pleasantness of affective and marijuana-related stimuli) and emotional Stroop (attentional bias to affective stimuli). On the pleasantness rating task, active marijuana increased response latency to negatively valenced and marijuana-related (vs. neutral) visual stimuli, beyond a general slowing of response. Active marijuana also increased pleasantness ratings of marijuana images, although to a lesser extent than placebo due to reduced marijuana urge after smoking. Overall, active marijuana did not acutely change processing of positive emotional stimuli. There was no evidence of attentional bias to affective word stimuli on the emotional Stroop task with the exception of attentional bias to positive word stimuli in the subgroup of marijuana users with cannabis dependence. Marijuana may increase allocation of attentional resources toward marijuana-specific and negatively valenced visual stimuli without altering processing of positively valenced stimuli. Marijuana-specific cues may be more attractive with higher levels of marijuana craving and less wanted with low craving levels.

Toward Automated Testing of Geo-Distributed Replica Selection Algorithms

Many geo-distributed systems rely on a replica selection algorithms to communicate with the closest set of replicas. Unfortunately, the bursty nature of the Internet traffic and ever changing network conditions present a problem in identifying the best choices of replicas. Suboptimal replica choices result in increased response latency and reduced system performance. In this work we present GeoPerf, a tool that tries to automate testing of geo-distributed replica selection algorithms. We used GeoPerf to test Cassandra and MongoDB, two popular data stores, and found bugs in each of these systems.

Effects of the noncompetitive N-methyl-D-aspartate receptor antagonist ketamine on visual signal detection performance in rats.

The noncompetitive N-methyl-D-aspartate receptor antagonist ketamine produces consistent, rapid, and sustained antidepressant effects in patients suffering from treatment-resistant depression. However, ketamine-induced cognitive impairments remain a major concern. The present study sought to extend the preclinical evaluation of ketamine-induced cognitive impairments by evaluating the dose (1.0-18.0 mg/kg) and time-course (10 min-24 h) of effects of ketamine on sustained attention using a visual signal detection procedure in rats. Overall, ketamine (10.0-18.0 mg/kg) dose-dependently decreased percent hit and correct rejection accuracy. Additionally, these same doses of ketamine increased response latency and trial omissions. In the time-course study, treatment with 18.0 mg/kg ketamine produced the greatest decrease in visual signal detection performance at 10 min, when ketamine decreased percent hit and correct rejection accuracy as well as increased response latency and trial omissions, but returned to saline baseline controls by 100 min. In conclusion, acute ketamine inhibited sustained attention in rats performing a visual signal detection task; however, these effects were short in duration, similar to the short duration (<2 h) of psychotomimetic effects reported in low-dose ketamine treatment in depressed patients.

Development and Validation of an Implicit Measure of Meta-Motivational States

The development of an easily-administered, valid and reliable meta-motivational state measure, capable of assessing the full spectrum of states, is needed to progress the understanding and application of reversal theory (Apter, 2013). The present paper outlines an adaptation of the Stroop protocol to implicitly measure meta-motivational states, and two subsequent validation studies. Consistent with Stroop principles, it was hypothesised that state congruent stimuli would capture individuals’ attention causing an increased response latency (e.g., Ayres & Sonandre, 2002). Study one (n = 68) assessed the concurrent validity of the Meta-Motivational Stroop task (MMS) against two widely-used explicit measures of state, the Telic/Paratelic State Inventory (T/PSI; O’Connell & Calhoun, 2001) and the State of Mind Indicator for Athletes (SOMIFA; Kerr & Apter, 1999). Contrary to expectations emotionally incongruent stimuli caused a delayed response, interpreted as an interference effect (Rothermund, 2003). Study two (n = 30) manipulated state, through expressive writing and imagery, to assess the ability of the Stroop task to detect changes in state. Results offered some support for the interference effect, with incongruent stimuli resulting in an increased response latency when writing from a telic perspective. Taken together, results suggest an implicit measure of meta-motivational state has some promise, particularly given the observed limitations of explicit measures.

Effects of acute and sustained pain manipulations on performance in a visual-signal detection task of attention in rats.

Preclinical Research Patients with pain often display cognitive impairment including deficits in attention. The visual-signal detection task (VSDT) is a behavioral procedure for assessment of attention in rodents. Male Sprague Dawley rats were trained in a VSDT and tested with three different noxious stimuli: (i) intraperitoneal injection of lactic acid; (ii) intraplantar injection of formalin; and (iii) intraplantar injection of complete Freund's adjuvant (CFA). The muscarinic acetylcholine receptor antagonist, scopolamine was also tested as a positive control. Scopolamine (0.01-1.0 mg/kg) dose dependently reduced accuracy and increased response latencies during completed trials with higher scopolamine doses increasing omissions. Lactic acid (0.56-5.6% ip) also increased response latencies and omissions, although it failed to alter measures of response accuracy. Formalin produced a transient decrease in accuracy while also increasing both response latency and omissions. CFA failed to alter VSDT performance. Although VSDT effects were transient for formalin and absent for CFA, both treatments produced mechanical allodynia and paw edema for up to 7 days. These results support the potential for noxious stimuli to produce a pain-related disruption of attention in rats. However, relatively strong noxious stimulation appears necessary to disrupt performance in this version of the VSDT.

Longitudinal alterations to brain function, structure, and cognitive performance in healthy older adults: A fMRI-DTI study

Cross-sectional research has shown that older adults tend to have different frontal cortex activation patterns, poorer brain structure, and lower task performance than younger adults. However, relationships between longitudinal changes in brain function, brain structure, and cognitive performance in older adults are less well understood. Here we present the results of a longitudinal, combined fMRI-DTI study in cognitive normal (CN) older adults. A two time-point study was conducted in which participants completed a task switching paradigm while fMRI data was collected and underwent the identical scanning protocol an average of 3.3 years later (SD=2 months). We observed longitudinal fMRI activation increases in bilateral regions of lateral frontal cortex at time point 2. These fMRI activation increases were associated with longitudinal declines in WM microstructure in a portion of the corpus callosum connecting the increasingly recruited frontal regions. In addition, the fMRI activation increase in the left VLPFC was associated with longitudinal increases in response latencies. Taken together, our results suggest that local frontal activation increases in CN older adults may in part reflect a response to reduced inter-hemispheric signaling mechanisms.

Impaired attention and synaptic senescence of the prefrontal cortex involves redox regulation of NMDA receptors.

Young (3-6 months) and middle-age (10-14 months) rats were trained on the five-choice serial reaction time task. Attention and executive function deficits were apparent in middle-age animals observed as a decrease in choice accuracy, increase in omissions, and increased response latency. The behavioral differences were not due to alterations in sensorimotor function or a diminished motivational state. Electrophysiological characterization of synaptic transmission in slices from the mPFC indicated an age-related decrease in glutamatergic transmission. In particular, a robust decrease in N-methyl-D-aspartate receptor (NMDAR)-mediated synaptic responses in the mPFC was correlated with several measures of attention. The decrease in NMDAR function was due in part to an altered redox state as bath application of the reducing agent, dithiothreitol, increased the NMDAR component of the synaptic response to a greater extent in middle-age animals. Together with previous work indicating that redox state mediates senescent physiology in the hippocampus, the results indicate that redox changes contribute to senescent synaptic function in vulnerable brain regions involved in age-related cognitive decline.

Bilinguals at the “cocktail party”: Dissociable neural activity in auditory–linguistic brain regions reveals neurobiological basis for nonnative listeners’ speech-in-noise recognition deficits

We examined a consistent deficit observed in bilinguals: poorer speech-in-noise (SIN) comprehension for their nonnative language. We recorded neuroelectric mismatch potentials in mono- and bi-lingual listeners in response to contrastive speech sounds in noise. Behaviorally, late bilinguals required ∼10dB more favorable signal-to-noise ratios to match monolinguals’ SIN abilities. Source analysis of cortical activity demonstrated monotonic increase in response latency with noise in superior temporal gyrus (STG) for both groups, suggesting parallel degradation of speech representations in auditory cortex. Contrastively, we found differential speech encoding between groups within inferior frontal gyrus (IFG)—adjacent to Broca’s area—where noise delays observed in nonnative listeners were offset in monolinguals. Notably, brain-behavior correspondences double dissociated between language groups: STG activation predicted bilinguals’ SIN, whereas IFG activation predicted monolinguals’ performance. We infer higher-order brain areas act compensatorily to enhance impoverished sensory representations but only when degraded speech recruits linguistic brain mechanisms downstream from initial auditory-sensory inputs.

Effects of pinch-grip training on motor function and corticomotor excitability in people with Parkinson’s disease

s / Brain Stimulation 8 (2015) 412e427 416 Understanding the actions of other people is a crucial skill to function in a social environment. When observing actions, one can understand implied goals and mental-states. The mirror neuron system (MNS) plays an important role in action understanding by internal simulation of the observed movements. This simulation process may be sufficient to decipher thoughts and intentions incorporated in an action. However, a more abstract mentalizing network may be necessary to efficiently process these inner states. In a recent fMRI study, we demonstrated that nodes of the theory-of-mind network (ToM) are activated when participants observe hesitations conveyed in hand movements. However, activation of a brain region does not the imply its necessity to perform the given task. Therefore, we designed a repetitive TMS study using the same experimental paradigm. On three experimental days, participants received 15 minutes of 1-Hz inhibitory rTMS stimulation, either on a MNS node (PF in the inferior parietal lobe), a ToM node (temporo-parietal junction (TPJ)), or a control region (vertex). After the stimulation, the participants performed three tasks: judging the size of a chosen object based on hand aperture, judging the level of hesitation and a control task. The first hypothesis was that a virtual lesion of PF would impair the performance in the hand aperture and hesitation task because they require the analysis of movement nuances. The second hypothesis was that a virtual lesion of the TPJ would influence the performance on the hesitation task only, because it requires inference about a mental state (confidence of choice). As predicted, we observed increased response latencies on the hand aperture task following the PF stimulation and increased response latencies on the hesitation task following both PF and TPJ stimulation. These results suggest that the TPJ is necessary to efficiently decipher mental states encoded in hand actions.

Treatment of Post-stroke Motor Dsyfunction by Interleaved Trancranial Magnetic Stimulation Combined with Functional MRI (TMS-fMRI)

s / Brain Stimulation 8 (2015) 412e427 416 Understanding the actions of other people is a crucial skill to function in a social environment. When observing actions, one can understand implied goals and mental-states. The mirror neuron system (MNS) plays an important role in action understanding by internal simulation of the observed movements. This simulation process may be sufficient to decipher thoughts and intentions incorporated in an action. However, a more abstract mentalizing network may be necessary to efficiently process these inner states. In a recent fMRI study, we demonstrated that nodes of the theory-of-mind network (ToM) are activated when participants observe hesitations conveyed in hand movements. However, activation of a brain region does not the imply its necessity to perform the given task. Therefore, we designed a repetitive TMS study using the same experimental paradigm. On three experimental days, participants received 15 minutes of 1-Hz inhibitory rTMS stimulation, either on a MNS node (PF in the inferior parietal lobe), a ToM node (temporo-parietal junction (TPJ)), or a control region (vertex). After the stimulation, the participants performed three tasks: judging the size of a chosen object based on hand aperture, judging the level of hesitation and a control task. The first hypothesis was that a virtual lesion of PF would impair the performance in the hand aperture and hesitation task because they require the analysis of movement nuances. The second hypothesis was that a virtual lesion of the TPJ would influence the performance on the hesitation task only, because it requires inference about a mental state (confidence of choice). As predicted, we observed increased response latencies on the hand aperture task following the PF stimulation and increased response latencies on the hesitation task following both PF and TPJ stimulation. These results suggest that the TPJ is necessary to efficiently decipher mental states encoded in hand actions.

The role of the theory of mind network in action observation - an rTMS study

Understanding the actions of other people is a crucial skill to function in a social environment. When observing actions, one can understand implied goals and mental-states. The mirror neuron system (MNS) plays an important role in action understanding by internal simulation of the observed movements. This simulation process may be sufficient to decipher thoughts and intentions incorporated in an action. However, a more abstract mentalizing network may be necessary to efficiently process these inner states. In a recent fMRI study, we demonstrated that nodes of the theory-of-mind network (ToM) are activated when participants observe hesitations conveyed in hand movements. However, activation of a brain region does not the imply its necessity to perform the given task. Therefore, we designed a repetitive TMS study using the same experimental paradigm. On three experimental days, participants received 15 minutes of 1-Hz inhibitory rTMS stimulation, either on a MNS node (PF in the inferior parietal lobe), a ToM node (temporo-parietal junction (TPJ)), or a control region (vertex). After the stimulation, the participants performed three tasks: judging the size of a chosen object based on hand aperture, judging the level of hesitation and a control task. The first hypothesis was that a virtual lesion of PF would impair the performance in the hand aperture and hesitation task because they require the analysis of movement nuances. The second hypothesis was that a virtual lesion of the TPJ would influence the performance on the hesitation task only, because it requires inference about a mental state (confidence of choice). As predicted, we observed increased response latencies on the hand aperture task following the PF stimulation and increased response latencies on the hesitation task following both PF and TPJ stimulation. These results suggest that the TPJ is necessary to efficiently decipher mental states encoded in hand actions.