Response Latency Research Articles

Subliminal priming modulates motor sequence learning.

Sequential behaviour is underpinned by the selection and inhibition of movement at appropriate points in space and time. Sequences embedded among movement patterns must be learnt, yet the contribution of response selection and inhibition to the acquisition of motor sequences remains poorly understood. We addressed this issue by overlaying the serial reaction time task (SRTT) with subliminal masked primes that differentially weighed response tendencies. In Experiment 1, twenty-four healthy young adults, and in Experiment 2, thirty-six participants, performed the SRTT with congruent (same position), incongruent (different position), or neutral (no prime) subliminal masked primes. Each condition featured an embedded eight-digit (Experiment 1) or ten-digit (Experiment 2) second-order sequence, with conditions presented in counterbalanced order during a single session. Sequence specific learning was observed under neutral and congruent prime conditions. Independent of sequence awareness, congruent primes reduced initial response latency and led to greater sequence specific learning compared with neutral primes. However, incongruent primes appeared to attenuate learning (Experiment 1). These results demonstrate that prime congruency modulates sequence specific learning below the threshold of conscious awareness. Congruent primes may elevate the salience of stimulus-response compounds and accentuate learning, but at the cost of increased awareness. Incongruent primes, and the induction of response conflict, attenuate sequence specific learning (Experiment 1) and may prevent the formation of cross-temporal contingencies necessary for implicit motor sequence learning.

Effect of Cochlear Implantation on Air Conduction and Bone Conduction Elicited Vestibular Evoked Myogenic Potentials-A Scoping Review.

Background/Objectives: Cochlear implantation (CI) is an effective intervention for individuals with severe to profound hearing loss; however, it may impact vestibular function due to its proximity to related anatomical structures. Vestibular evoked myogenic potentials (VEMPs) assess the function of the saccule and utricle, critical components of the vestibular system. This review examines CI's impact on air conduction (AC) and bone conduction (BC) VEMP responses. Methods: A scoping review was conducted following PRISMA guidelines, using databases such as Medline, Embase, Cochrane Library, Scopus, and ProQuest Dissertations. Studies reporting on AC and/or BC-VEMP in CI recipients were included. Data extraction focused on VEMP response rates, amplitudes, and latencies pre- and post-CI. Risk of bias/quality assessment was performed using the Newcastle-Ottawa Scale. Results: Out of 961 studies identified, 4 met the inclusion criteria, encompassing a total of 245 CI-implanted ears. Results indicated that AC-VEMP responses were often reduced or absent post-CI, reflecting the influence of surgical changes in the middle ear mechanics rather than otolith dysfunction. In contrast, BC-VEMP responses were more consistently preserved, suggesting that BC stimuli bypass the middle ear and more accurately delineate otolith function. Variations in VEMP outcomes were noted depending on the surgical approach and individual patient factors. Conclusions: CI impacts vestibular function as measured by VEMP, with AC-VEMP showing greater susceptibility to postoperative changes compared to BC-VEMP. The presence of preserved BC-VEMP alongside absent AC-VEMP underscores the need to differentiate between these measures in assessing vestibular function.

How "Light" Is "Light Smoking"? On the Cognitive Power of Nicotine Dependence.

In recent years, habits related to smoking have been changing. An increasing portion of light/occasional smokers tend to define themselves as non-smokers, leading to an incorrect perception of the risks that smoking even a few cigarettes can entail. In this study, we investigated the nicotine-induced cognitive distortion in young, higher-education students with low/moderate dependence (as indexed by the Fagerstrom questionnaire). The study involved 111 participants (62 female; mean age 24.43 ± 3.77) divided into smokers and non-smokers, who responded to specific questionnaires to evaluate their attachment style, emotion dysregulation, and state anxiety. Their response to smoking-related cues following emotional stimulation was experimentally evaluated, with participants being made to choose between care- or smoking-related images, following the presentation of threatening or neutral stimuli. The results show a cognitive bias in smokers, with participants choosing smoking-related stimuli significantly more often than non-smokers, with a slower reaction time, regardless of emotional cues. Emotion dysregulation and attachment style were also significantly correlated with response choice but not with response latency. Overall, our data indicate that there is no such thing as light use of nicotine and that smoking, even if not continuous, determines cognitive biases that lead to a vision of the environment as a function of substance seeking.

The Effect of Different Adaptation Formulas on Mid-Latency Auditory Evoked Potentials in Adults with Hearing Aids.

We were conducting this study to evaluate the effects of different hearing aid adaptation formulas on middle latency responses (MLR) in adult hearing aid users. The study included 72 participants: those with moderate hearing loss using hearing aids with two different formulas for the last year, those with moderate hearing loss not using hearing aids, and those without hearing loss. Sixteen participants using NAL-NL1 and NAL-RP formulas were Group 1; twenty using NAL-NL2 and DSL formulas were Group 2; fifteen with hearing loss not using devices were Group 3; and twenty-one without hearing loss were Group 4. We obtained and compared MLR responses, including Na latency, Pa latency, and Na-Pa amplitude. Group 1 mean Na-Pa amplitude value was found to be higher than Group 2 (p = 0.001). No significant difference was observed between Group 1 and Group 2 in terms of Na latency and Pa latency values (p = 0.001; p = 0.035). It was observed that the mean Na-Pa amplitude values in Group 1 and Group 2 were higher than Group 3 (p = 0.001), but this elevation reached the level of statistical significance only in Group 1. No difference was observed between Group 1, Group 2, and Group 3 in terms of Na latency and Pa latency values (p = 0.001; p = 0.035). Compared with those without hearing loss (Group 4), participants with hearing loss (Group 1, Group 2, and Group 3) had longer Na latency and Pa latency values (p = 0.001; p = 0.035), and Na-Pa amplitudes were lower (p = 0.001). The effect of current (tested) hearing aid usage time on Na latency, Pa latency, and Na-Pa amplitude values of Group 1 and Group 2 was not observed. In all groups, there was a positive correlation between audiometric airway/bone conduction pure tone averages and speech acquisition threshold values, Na latency and Pa latency values, and a negative correlation between Na-Pa amplitude values. In all groups, there was a negative correlation between speech discrimination scores and Na and Pa latency values, as well as a positive correlation between Na and Pa amplitude values. There was a positive correlation between age and Pa latency values in all groups, as well as a negative correlation between Na and Pa amplitude values. Middle latency responses are affected by the presence of hearing loss, the use of hearing aids, and different hearing aid adaptation formulas. MLR measurements with a hearing aid can be used as an objective test to evaluate the benefit of hearing aid use.

Revealing hidden interactions in mean performance through distributional analyses: Evidence from Chinese lexical decision performance.

Important insights in visual word recognition have been provided by studies examining the combined influence of multiple factors on participants' mean response times to English words in the lexical decision task. However, to make progress towards a complete understanding of how meaning is activated by print, researchers need to conduct more detailed analyses of behavioral patterns beyond mean response latencies and accuracies, particularly how variables influence different components of response time distributions. Moreover, it is critical to extend patterns found in English to the diverse scripts encountered by readers across the world. The present study is the first to explore the theoretically important effects of stimulus quality and word frequency on lexical decisions involving two-character Mandarin Chinese and Cantonese Chinese words, using participants from Singapore and Hong Kong, respectively. Despite the profound differences between the English and Chinese writing systems, we observed remarkably similar trade-offs in the stimulus quality × word frequency interaction across different portions of the response time distribution for both orthographies, indicating that the optimization of lexical processing by leveraging available codes in response to task demands extends across multiple and highly diverse writing systems.

Following Medical Advice of an AI or a Human Doctor? Experimental Evidence Based on Clinician-Patient Communication Pathway Model

ABSTRACT Medical large language models are being introduced to the public in collaboration with governments, medical institutions, and artificial intelligence (AI) researchers. However, a crucial question remains: Will patients follow the medical advice provided by AI doctors? The lack of user research makes it difficult to provide definitive answers. Based on the clinician-patient communication pathway model, this study conducted a factorial experiment with a 2 (medical provider, AI vs. human) × 2 (information support, low vs. high) × 2 (response latency, slow vs. fast) between-subjects design (n = 535). The results showed that participants exhibited significantly lower adherence to AI doctors’ advice than to human doctors. In addition, the interaction effect suggested that, under the slow-response latency condition, subjects perceived greater health benefits and patient-centeredness from human doctors, while the opposite was observed for AI doctors.

Performance Tuning in Cloud Environments: Techniques for Enhancing Application Efficiency

This research aims at examining the strategies of performance tuning in cloud computing with emphasis on the optimization of applications, minimized response time, and optimal, affordable resource utilization. The research therefore includes a systematic literature review together with quantitative findings through empirical testing of the proposed model on Amazon Web Services (AWS), Microsoft Azure, and Google Cloud Platform (GCP), in addition to qualitative insights of experts. Auto-scaling, load balancing caching, database optimizing, integration with edge computing and predictive workloads using Artificial Intelligence are the aspects that are also studied as key performance tuning latter. Soon, the investigation, which was made based on the results from applying the four techniques on different applications and two clouds, demonstrates the strength of each technique in achieving different goals. While auto-scale and load balance feature is very helpful in control of workload fluctuations, the caching and database optimization helps in the efficient retrieval of the data. Edge computing reduces latency in response to real-time applications, and the application of artificial intelligence in workload forecast smoothes resource utilization in environments with a rapidly changing workload. Accordingly, the research has shown need for careful choosing of suitable performance-oriented interventions to enhance the application’s interactions, decrease CPU utilization, and cut costs in a cloud environment. Lastly, this work offers practical knowledge about the methods of cloud performance tuning to support better application deployment in the cloud environments.

Age dependent deficits in speech recognition in quiet and noise are reflected in MGB activity and cochlear onset coding: Temporal delays in phoneme processing with aging

The slowing and reduction of auditory responses in the brain are recognized side effects of increased pure tone thresholds, impaired speech recognition, and aging. However, it remains controversial whether central slowing is primarily linked to brain processes as atrophy, or is also associated with the slowing of temporal neural processing from the periphery. Here we analyzed electroencephalogram (EEG) responses that most likely reflect medial geniculate body responses to passive listening of phonemes in 80 subjects ranging in age from 18 to 76 years, in whom the peripheral auditory responses had been analyzed in detail (Schirmer et al., 2024). We observed that passive listening to vowels and phonemes, specifically designed to rely on either temporal fine structure (TFS) for frequencies below the phase locking limit (<1500 Hz), or on the temporal envelope (TENV) for frequencies above phase locking limit, entrained lower or higher neural EEG responses. While previous views predict speech content, particular in noise to be encoded through TENV, here a decreasing phoneme-induced EEG amplitude over age in response to phonemes relying on TENV coding could also be linked to poorer speech-recognition thresholds in quiet. In addition, increased phoneme-evoked EEG delay could be correlated with elevated extended high-frequency threshold (EHF) for phoneme changes that relied on TFS and TENV coding. This may suggest a role of pure-tone threshold averages (PTA) of EHF for TENV and TFS beyond sound localization that is reflected in likely medial geniculate body (MGB) delays. When speech recognition thresholds were normalized for pure-tone thresholds, however, the EEG amplitudes remained insignificant, and thereby became independent of age. Under these conditions, poor speech recognition in quiet was found together with a delay in EEG response for phonemes that relied on TFS coding, while poor speech recognition in ipsilateral noise was observed as a trend of shortened EEG delays for phonemes that relied on TENV coding. Based on previous analyses performed in these same subjects, elevated thresholds in extended high-frequency regions were linked to cochlear synaptopathy and auditory brainstem delays. Also, independent of hearing loss, poor speech-performing groups in quiet or with ipsilateral noise during TFS or TENV coding could be linked to lower or better outer hair cell performance and delayed or steeper auditory nerve responses at stimulus onset. The amplitude and latency of MGB responses to phonemes requiring TFS or TENV coding, dependent or independent of hearing loss, may thus be a new predictor of poor speech recognition in quiet and ipsilateral noise that links deficits in synchronicity at stimulus onset to neocortical activity. Amplitudes and delays of speech EEG responses to syllables should be reconsidered for future hearing-aid studies.

Quercetin Alleviates Diabetic Peripheral Neuropathy by Regulating Axon Guidance Factors and Inhibiting the Rho/ROCK Pathway in vivo and in vitro.

The axon guidance factors and Rho/ROCK pathway play crucial roles in axon protection and nerve repair and has been implicated in the development of diabetic peripheral neuropathy (DPN). This study investigates the protective effects of quercetin against DPN, focusing on axon guidance factors and Rho/ROCK pathway. DPN was induced by intraperitoneal injection of streptozotocin (STZ) to Sprague-Dawley rats. The DPN model rats were allocated into three groups and administered quercetin at two different doses (30 mg/kg/day and 60 mg/kg/day) or a placebo. Concurrently, healthy rats were divided into two groups and administered either a placebo or quercetin (60 mg/kg/day). Administration was initiated 8weeks post-STZ injection and continued for a duration of six weeks. To assess quercetin's neuroprotective effects, biochemical analyses, neurological function tests (mechanical threshold, thermal response latency, motor nerve conduction velocity), and morphological assessments via transmission electron microscopy were conducted. Immunofluorescence and immunohistochemical assays were performed on sciatic nerve tissue and high glucose-induced RSC96 rat Schwann cells to explore quercetin's pharmacological effects on DPN. Quercetin exhibited neuroprotective effects on both DPN rats and RSC96 cells exposed to high-glucose. A six-week administration of quercetin at both doses significantly improved the peripheral neurological functions and alleviated the pathological changes in sciatic nerve of DPN rats (P<0.05). Mechanistically, quercetin markedly upregulated the expressions of axonal growth factors, Slit-2 and Netrin-1 in vivo and in vitro (P<0.05), while inhibiting the aberrant activation of Rho/ROCK signaling pathway in the sciatic nerve of DPN rats. Our findings suggest that quercetin improves DPN through a novel mechanism, indicating its potential as a therapeutic agent for DPN therapy.

Phonology facilitates deeply opaque logographic writing.

Phonological knowledge plays a pivotal role in many aspects of language processing, but it remains controversial whether it is required for writing. In the present study, we examined the issue by focusing on written production in an opaque logographic script (kanji) with highly irregular pronunciation rules, which allowed for a rigorous test of whether or not phonology contributes to writing. Using a phonological priming paradigm in two experiments, we measured response latency while participants orally named target pictures or wrote down their names in kanji. Each target was preceded by a phonographic character (kana) which represented the same sound (mora) as the beginning of the target name or a different mora. By manipulating the degree of phonological overlap between primes and target names (i.e., morae, consonants and vowels), we found that only the moraic overlap could speed up word production in logographic writing (Experiment 1). In contrast, naming response was facilitated by mora-overlap as well as vowel-overlap. This between-task difference in phonological encoding suggests that phonological codes for spoken production do not necessarily precede orthographic access during logographic writing. In Experiment 2, we further found that the facilitatory effects of moraic information did not differ in magnitude between writing and naming when primes were masked and presented more briefly, suggesting a net component of bottom-up phonological activation which contributes to logographic writing. Collectively, we propose that orthographic codes of kanji are accessed directly from semantics, whereas phonology plays a non-specific modulatory role to enhance neurocognitive systems involved in writing.

Swiftly Chasing Gravitational Waves across the Sky in Real Time

We introduce a new capability of the Neil Gehrels Swift Observatory, dubbed “continuous commanding,” that achieves 10 s latency response time on orbit to unscheduled target-of-opportunity requests received on the ground. We show that this will allow Swift to respond to premerger (early-warning) gravitational-wave (GW) detections, rapidly slewing the Burst Alert Telescope (BAT) across the sky to place the GW origin in the BAT field of view at or before merger time. This will dramatically increase the GW/gamma-ray burst (GRB) codetection rate and enable prompt arcminute localization of a neutron star merger. We simulate the full Swift response to a GW early-warning alert, including input sky maps produced at different early-warning times, a complete model of the Swift attitude control system, and a full accounting of the latency between the GW detectors and the spacecraft. 60 s of early warning can double the rate of a prompt GRB detection with arcminute localization, and 140 s guarantees observation anywhere on the unocculted sky, even with localization areas ≫1000 deg2. While 140 s is beyond current GW detector sensitivities, 30–70 s is achievable today. We show that the detection yield is now limited by the latency of LIGO/Virgo cyberinfrastructure and motivate a focus on its reduction. Continuous commanding has been integrated as a general capability of Swift, significantly increasing its versatility in response to the growing demands of time-domain astrophysics. We demonstrate this potential on an externally triggered fast radio burst (FRB), slewing 81° across the sky, and collecting X-ray and UV photons from the source position <150 s after the trigger was received from the Canadian Hydrogen Intensity Mapping Experiment, thereby setting the earliest and deepest such constraints on high-energy activity from nonrepeating FRBs. The Swift Team invites the community to consider and propose novel scientific applications of ultra-low-latency UV, X-ray, and gamma-ray observations.

A circuit model for transsaccadic space updating and mislocalization.

We perceive a stable, continuous world despite drastic changes of retinal images across saccades. However, while persistent objects in daily life appear stable across saccades, stimuli flashed around saccades can be grossly mislocalized. We address this puzzle with our recently proposed circuit model for perisaccadic receptive-field (RF) remapping in LIP and FEF. The model uses center/surround connections to store a relevant stimulus' retinal location in memory as a population activity. This activity profile is updated across each saccade by directional connections gated by the corollary discharge (CD) of the saccade command. The updating is a continuous backward (against the saccade) shift of the population activity (equivalent to continuous forward remapping of the RFs), whose cumulative effect across the saccade is a subtraction of the saccade vector. The model explains forward and backward translational mislocalization for stimuli flashed around the saccade onset and offset, respectively, as insufficient and unnecessary cumulative updating after the saccade, caused by the sluggish CD time course and visual response latency. We confirm the model prediction that for perisaccadic RFs measured with flashes before the saccades, the final forward remapping magnitudes after the saccades are smaller for later flashes. We discuss the possibility that compressive mislocalization results from a brief reduction of attentional remapping and repulsion. Although many models of RF remapping, transsaccadic updating, and perisaccadic mislocalization have been proposed, our work unifies them into a single circuit mechanism and suggests that the brain uses "unaware" decoders which do not distinguish between different origins of neurons' activities.

Like Shooting Phish in a Barrel: Cue Utilization and Cognitive Reflection Aid Performance in Controlled, but Not Naturalistic Phishing Tasks

The study tested the role of cue utilization and cognitive reflection tendencies in email users’ phishing decision capabilities in both controlled and naturalistic settings. 94 university students completed measures of their phishing cue utilization and cognitive reflection, a phishing decision task, and a naturalistic simulated phishing campaign, in which they were sent simulated phishing emails to their personal inboxes. For the phishing decision task, results revealed that participants with lower cognitive reflection tendencies were more likely to misclassify genuine emails as phishing, compared to participants with higher cognitive reflection. Further, participants with higher cognitive reflection and lower cue utilization took the most time to diagnose emails, but participants low in both cue utilization and cognitive reflection demonstrated the shortest response latencies. These findings suggest that greater cognitive reflection can offset lower levels of cue utilization. For the naturalistic simulation, neither cue utilization nor cognitive reflection predicted an increased propensity to interact with a suspicious email. This result highlights a potential gap between phishing investigations conducted in controlled and naturalistic settings. The implications extend to future research, emphasizing the need for studies that employ naturalistic methodologies to better understand and address phishing threats in real-world environments.

Effects of wearing a surgical face mask on cognitive functioning and mood states: a randomised controlled trial in young adults.

Despite significant public concerns voiced about wearing face masks and reports from healthcare workers of adverse effects on cognition, research into potential adverse effects remains limited. The present trial investigated the effects of wearing a surgical face mask for prolonged periods on cognitive functioning and mood. We tested 42 university students (18-36years old) using a controlled counterbalanced crossover design that involved a mask session and a control session, separated by 1week. The two sessions were identical except that on the day of the mask session, participants were asked to wear a surgical mask for at least 8h and to continue wearing it while visiting our laboratory, during which cognitive performance and mood were assessed as per the control session. Results showed that participants reported feeling less happy and more tense during the mask session compared to no-mask control. Additionally, cognitive performance differed between the two sessions for a selective attention task, reflecting slower response latencies during the mask session, which for the most part appeared to be driven by those who felt anxious wearing the mask. Although significant differences emerged for only two of six mood scales and one of eight cognitive tests, the evidence of adverse effects in a university population signals a need for research investigating vulnerable populations. Individuals with elevated anxiety may be particularly important to target.Trail Registration: This randomized controlled trial was retrospectively registered (ACTRN12620001215910). Date registered: 16/11/2020, retrospectively registered.

Non-sentential responses to requests for information.

When faced with requests for information ("Where did you go last night?"), why do speakers make non-sentential replies ("The movies") rather than full sentence replies ("I went to the movies")? We examine the role that pragmatic factors (politeness and formality) and memory factors (the speaker's ability to retrieve the answer to the question) play in determining whether speakers generate a non-sentential reply. Participants answered a series of questions about their lives. Pragmatic factors affected the participants' responses. Speakers instructed to be polite or formal made fewer non-sentential replies than speakers who did not receive specific instructions. Memory retrieval (indexed both by the time required for the participant to begin their response and by the presence of disfluencies at the beginning of the response) did not have a straightforward relationship to the production of non-sentential replies. The effect of response latency and disfluencies depended on whether the participants were told to be polite or formal (or if they were given no instruction at all).

Evaluation of auditory middle latency response during the menstrual cycle

Aim: The hormone levels during the menstrual cycle, directly and indirectly, affect the hearing system. In our study, it was aimed to examine the effects of changing hormone levels during the menstrual cycle on auditory middle latency responses in healthy individuals with different stimuli types and the psychosomatic effects of premenstrual complaints on auditory performance. Methods: In the study, 20 healthy women aged 18-35 years, with regular menstrual cycles and no auditory or vestibular complaints were evaluated for auditory middle latency responses with click and level-specific (LS) CE-Chirp® stimuli during the menstruation period of the follicular phase (1-5 day, menstrual phase), the ovulation phase (14-17 day) and the luteal phase (21-28 day). To evaluate the effect of premenstrual complaints on auditory performance, the participants were asked 5 questions. Results: In the auditory middle latency assessment with click stimuli, a statistically larger Na-Pa amplitude was obtained in the menstruation phase compared to the ovulation phase in both ears. In the auditory middle latency evaluation with LS CE-Chirp® stimulus, statistically shortened Nb latencies were obtained in the right ear in the menstruation phase compared to the ovulation phase. Conclusion: Although the clear effect of changing gonadal hormone levels on auditory evoked middle latency responses could not be determined, the findings show that neural transmission increases in the menstrual phase when the estrogen level is low. Click stimulus is more sensitive to hormonal changes, and the use of click stimulus has been recommended in the later side of lesion studies. In our study, no psychosomatic effect of complaints in the premenstrual period on auditory performance was observed.

Exploring the flexibility of word position encoding in Chinese reading: the role of transposition effects

ABSTRACT Previous research in the alphabetic writing system has demonstrated that transposition distance (adjacent vs. non-adjacent) modulates word position encoding during sentence reading. To examine the generality of this pattern within a more holistic model of sentence processing, we investigated this effect in the logographic Chinese writing system. We manipulated the number of words intervening between the transposed words, creating four conditions: none, one, two, and three intervening words. Participants performed a rapid grammaticality judgment task. Results showed longer response latencies and higher error rates when words were transposed adjacent to each other compared to non-adjacent transpositions. Furthermore, more errors and longer response times were observed when one word intervened between the transposed words compared to two or three intervening words. However, no significant differences emerged between the two- and three-word interval conditions. These findings suggest that word position encoding exhibits graded, flexible tolerance to transposition distance, constrained by proximity.

Central Auditory Processing Abilities in Children with Non-Syndromic Cleft Lip and Palate: An Electrophysiological Study.

The present study compared the central auditory processing abilities using electrophysiological tests in children with non-syndromic cleft lip and palate (NSCLP) and their age-matched control group. Thirty children aged 7 to 15 years were recruited for the study. Participants were divided into 2 groups. The clinical group (children with NSCLP) comprised 15 children, while the control group (craniofacially typical peers) comprised 15 children with normal hearing sensitivity and auditory processing skills. Electrophysiological tests, including auditory brainstem responses (ABR), binaural interaction component (BIC) of ABR, auditory late latency responses (ALLR), and P300 were assessed. The results showed deviant responses in ABR, BIC, and ALLR in children with NSCLP compared to craniofacially typical counterparts. However, no significant difference was observed in P300 between the two groups. Children with NSCLP may be at a higher risk of central auditory processing disorder due to their abnormal neural transmission in the auditory nervous system. Also, assessing auditory processing abilities in children with NSCLP should include electrophysiological tests in the test battery for additional information regarding neural transmission.

Neuronal sequences in population bursts encode information in human cortex.

Neural coding has traditionally been examined through changes in firing rates and latencies in response to different stimuli1-5. However, populations of neurons can also exhibit transient bursts of spiking activity, wherein neurons fire in a specific temporal order or sequence6-8. The human brain may utilize these neuronal sequences within population bursts to efficiently represent information9-12, thereby complementing the well-known neural code based on spike rate or latency. Here we examined this possibility by recording the spiking activity of populations of single units in the human anterior temporal lobe as eight participants performed a visual categorization task. We find that population spiking activity organizes into bursts during the task. The temporal order of spiking across the activated units within each burst varies across stimulus categories, creating unique stereotypical sequences for individual categories as well as for individual exemplars within a category. The information conveyed by the temporal order of spiking activity is separable from and complements the information conveyed by the units' spike rates or latencies following stimulus onset. Collectively, our data provide evidence that the human brain contains a complementary code based on the neuronal sequence within bursts of population spiking to represent information.

Effects of Urban Lighting at Night on Daytime Songbird Aggression

Many animals require sleep for daily functions. In spring, songbirds expend a great deal of energy early in the day by singing to attract mates and aggressively protecting territory. Some evidence suggests that artificial lighting at night (ALAN) in the environment of wild birds increases their nighttime activity that, in turn, contributes to sleep loss. This study investigated how ALAN affects northern cardinal (Cardinalis cardinalis) response to experimental aggressive intrusion by conspecifics. The hypothesis tested is that high ALAN near cardinal roosting spots would cause those individuals to have less energy for daytime aggressive behaviors. After selecting known dark and bright urban roosting locations, ALAN was measured at specific sites with active cardinal territories during nighttime hours. Observers returned in the morning to present cardinal territorial songs using standardized call playback protocols. Aggressive behaviors of responding cardinals were recorded and used to quantify aggression intensity. Standard aggression measures included response latency, distance from bird to speaker, number of songs, hops, and flip flops. An aggression index was obtained using factor analysis which confirmed that aggressive responses featured short latency and approach distances, few chips, and many songs, flip flops, and hops. Analysis of variance revealed that cardinals roosting in high ALAN engaged in significantly more aggressive morning responses; directly contradicting predictions and previously published findings. One possible explanation for this result is that high ALAN might improve sleep in cardinals. To test this, autonomous recording units (ARUs) were placed in study locations to record nighttime calling behaviors in high and low ALAN. Insufficient data were obtained to clarify whether nighttime activity was reduced significantly by ALAN exposure. However, results showed that nighttime activity by cardinals is strongly influenced by moonlight, and that determination of the influence of ALAN on nighttime and daytime avian behavior must include measures of lunar illumination.