bluuebunny/crossref_metadata_2025 huggingface dataset:
Circulatory Effects of Anticipation in a Light Isometric Handgrip Test
Authors: Mantysaari Matti J. , Antila Kari J. , Peltonen Tuomas E.
Published: February 2007

The effects of anticipation on circulatory reactions to a light isometric handgrip test (5% of maximal force maintained 1 min) and to a sham test, in which the active handgrip was omitted, were studied in a group of 10 young healthy male volunteers. Circulatory parameters were measured using ECG, sphygmomanometry, and impedance cardiography 60 s and 30 s before provocations as well as after 5, 15, 30, 45, and 60 s during provocations (blood pressure after 15, 30, and 45 s) in both supine and upright positions. Before the real handgrip diastolic and mean blood pressure as well as systemic vascular resistance were higher than before the sham test and these differences were similar in the supine and upright positions. In the real handgrip test the elevations in blood pressure and systemic vascular resistance were greater than in the sham test while heart rate, stroke volume, and cardiac index did not show any differences. In the reactions caused by the handgrip, the only difference between the two positions was seen in systolic blood pressure which increased more in the upright position.

It is concluded that anticipation of the real handgrip was associated with elevations in blood pressure and systemic vascular resistance as compared to anticipating the sham test, and this difference was similar in the two positions. Thus the anticipatory circulatory alterations did not seem to be dependent on the pre‐test hemodynamic state, which was quite different in the supine and upright positions. The circulatory effects of anticipation and light isometric exercise were rather similar suggesting that the central nervous activation associated with anticipating handgrip is not very different from that associated with the handgrip itself.
Stimulus‐Specific Patterns of Cardiovascular Reactivity in Type A and B Subjects: Evidence for Enhanced Vagal Reactivity in Type B
Authors: Muranaka Motoyasu , Lane James D. , Suarez Edward C. , Anderson Norman B. , Suzuki Jinichi , Williams Redford B.
Published: February 2007

Recent evidence suggests that the differences in cardiovascular reactivity between individuals exhibiting the Type A behavior pattern and those that do not are not limited to excessive betaadrenergic reactivity in Type A's. Research also suggests the possibility of a tendency for enhanced alpha‐adrenergically and vagally mediated cardiovascular reactivity in Type B's. In the present study, Type A and Type B subjects were exposed to stressor stimuli known to elicit either betaadrenergic or alpha‐adrenergic and vagal responses in the cardiovascular system. Heart rate, blood pressure, and forearm blood flow and vascular resistance responses were measured. The two Types did not differ in response to the beta‐adrenergic stimulus (mental arithmetic). However, the alpha‐adrenergic/vagal stimulus (cold face stimulus) produced more prolonged heart rate and blood flow responses in Type B subjects. Results suggest that Type B's show hyperreactivity (compared to Type A) when alpha‐adrenergic or vagal cardiovascular responses are elicited. The nature of this hyperreactivity suggests possible mechanisms for reduced cardiovascular disease risk in Type B individuals.
A Comparison of Two Model Systems of Associative Learning: Heart Rate and Eyeblink Conditioning in the Rabbit
Authors: Powell D.A. , Levine‐Bryce Dianne
Published: February 2007

In four classical conditioning experiments heart period and eyeblink responses were assessed concomitantly. The conditioned stimuli (CSs) were tones and the unconditioned stimulus (UCS) was a brief paraorbital electric shock. Using a 0.5‐s duration CS, bradycardiac conditioned responses that consisted of a 4–5 ms change from pre‐CS baseline occurred within 10–20 CS‐UCS presentations. However, eyeblink conditioned responses began to occur only after 100–150 CS–UCS presentations. A 1.0‐s CS duration resulted in bradycardiac conditioned responses of 15–30 ms change from pre‐CS baseline, which again reached asymptote within 10–20 trials. Using a 4‐s CS duration, in a differential classical conditioning paradigm, heart period discrimination between a reinforced CS+ and a nonreinforced CS− occurred within 10 trials; asymptotic performance of the heart period conditioned response occurred within 15 CS‐UCS presentations and consisted of a bradycardiac response of 40–50 ms for the 12th interbeat interval following tone onset. These data thus indicate that these two model systems of mammalian learning (based on heart period and eyeblink responses) show quite different acquisition functions. It is also significant that heart rate slowing always accompanied the eyeblink conditioned responses, even though increases in general electromyographic activity as well as eyeblink conditioned responses were simultaneously observed during CS presentation.
Event‐Related Brain Potentials Reflecting Processing of Relevant and Irrelevant Stimuli During Selective Listening
Authors: Alho K. , Sams M. , Paavilainen P. , Reinikainen K. , Näätänen R.
Published: February 2007

Event‐related brain potentials were recorded from the human scalp during selective listening to tone pips differing in location and/or pitch from irrelevant tones. The subjects' task was to discriminate infrequent deviant tones of lower intensity appearing among designated (relevant) tones. A large processing negativity was observed in the event‐related potentials to relevant tones differing from the irrelevant tones in location even when both tones randomly varied in pitch. Similarly, a large processing negativity was elicited by the relevant tones differing from the irrelevant tones in pitch even when the location of both tones varied randomly. The results support the theory that the processing negativity to relevant stimuli reflects a match of these stimuli with an “attentional trace,' an actively maintained neuronal representation of the physical feature(s) of relevant stimuli that distinguish these stimuli from the irrelevant stimuli. Furthermore, the infrequent lower‐intensity tones appearing among irrelevant tones elicited a mismatch negativity similar to the mismatch negativity elicited by target tones, equivalent lower‐intensity tones appearing among relevant tones. This indicates that these infrequent stimulus changes were automatically discriminated by the generator mechanism associated with mismatch negativity.
Furedy's Straw Man: Wrong Purpose
Authors: Pavloski Raymond
Published: February 2007

Furedy's (1989) characterization of the control system mode of analysis as a teleological form of explanation is based on a definition of purpose that is not used in my paper (Pavloski, 1989). He incorrectly describes reactivity as a controlled variable or condition, and incorrectly describes the control system error theory as not being falsifiable while ignoring the specific testing procedures proposed. His characterization of my diagram of a control system (Figure 1 in Pavloski, 1989) misrepresents the description given in the body of the paper: it is a diagram of cause‐effect relationships that when physically realized produce covariation of a reference signal and a controlled condition; it is not merely a restatement of observations (such as a stated relationship between motivation and performance). Finally, he misrepresents the attempts of theoreticians who attempt to explain emotion and motivation within the context of a mechanism that behaves.
Physiological Response Patterns to Cognitive Testing in Adults With Closed Head Injuries
Authors: Lehrer Paul M. , Groveman Alan , Randolph Christopher , Miller Michael H. , Pollack Irwin
Published: February 2007

Physiological measures were taken from 7 closed‐head‐injured patients and 7 control subjects while they took a series of cognitive tests: the finger tapping test from the Halstead Reitan battery, the Digit Symbol test from the WAIS‐R, a test of logical memory, and a paced arithmetic test. Physiological reactivity was assessed relative to rest periods, which occurred at the beginning and end of each session. The tests and physiological assessment were administered twice, approximately one month apart. The patient group performed more poorly on the cognitive tests, and showed less physiological reactivity during them than did the control group. This pattern was statistically significant for heart rate, frequency of electrodermal responses, and, during the initial session, respiration rate. The control group also showed greater finger pulse amplitude during the first posttest rest period in the first session, and greater constriction during a logical memory task in the second session. No significant between‐groups differences emerged for state or trait anxiety. The patients showed higher frontalis EMG and respiration rate during rest. These results suggest a pattern of poor physiological modulation for task performance in the patients with closed head injuries. The therapeutic implications are discussed.
Late Components of Auditory Event‐Related Potentials to Eight Equiprobable Stimuli in a Target Detection Task
Authors: McCallum W.C. , Barrett K. , Pocock P.V.
Published: February 2007

Fourteen normal subjects undertook a target detection task in which eight different but equiprobable stimuli were presented in an unpredictable sequence (four tone frequencies to either the left or the right ear). One tone/ear combination was designated as a target, to be responded to with a rapid button press. Event‐related potentials were recorded from an array of six scalp electrodes. In Condition 1 no responses were required; in Condition 2 a response was required to the highest tone in one designated ear; in Condition 3 a response was required to the second highest tone in the ear opposite to the Condition 2 target.

Event‐related potentials to the no‐task condition (1) included a P3‐type late positive component. P3 increased in amplitude to target tones in Conditions 2 and 3, but showed equally large amplitude increases and some decrease in latency to nontarget tones in those conditions. However, a frontal Slow Wave component was elicited more specifically by target stimuli. An attended ear effect was evident in a processing negativity that extended for some hundreds of milliseconds prefrontally, but tended to be comprised of two separate negativities over fronto‐central locations.
Estimation of Trial‐to‐Trial Variation in Evoked Potential Signals by Smoothing Across Trials
Authors: Turetsky Bruce I. , Raz Jonathan , Fein George
Published: February 2007

Averaging single trial evoked potential data to produce an estimate of the underlying signal obscures trial‐to‐trial variation in the response. We describe a method for estimating slow changes in the evoked potential signal by smoothing the data over trials. We discuss the crucial issue of deciding how much to smooth and suggest that an appropriate smoothing parameter is one that minimizes the estimated mean average square error of the smoothed data. Equations to estimate the mean average square error for a one‐dimensional local linear regression smoother are presented. Performance of the method is assessed using simulated evoked potential data with several different models of a changing signal and different values of the signal‐to‐noise ratio. We find that the method rarely imputes trial‐to‐trial variation to data sets that have an unchanging signal, while it almost always produces less error than averaging when estimating a varying signal. The ability of the method to reveal signal heterogeneity is hampered by very low signal‐to‐noise ratios. When applied to real auditory evoked potential data from a sample of elderly subjects, the method indicated a changing signal in 35% of all subjects and in 56% of subjects with signal‐to‐noise ratios above 0.6. Consistent patterns of variation in the auditory evoked potential were present in this sample.
The Effect of Small Variation of the Frequent Auditory Stimulus on the Event‐Related Brain Potential to the Infrequent Stimulus
Authors: Winkler. Istvan , Paavilainen Petri , Alho Kimmo , Reinikainen Kalevi , Sams Mikko , Naatanen Risto
Published: February 2007

We investigated whether the mismatch process between a rare stimulus and the trace of frequent stimulus, which generates the mismatch‐negativity component of the event‐related potential, can tolerate a small variation in the intensity of the frequent stimulus. Series of short tone pips were presented to 10 subjects while they were reading a book and ignoring the auditory stimuli. The intensity (mean 80dB) of the frequent stimulus (600 Hz) varied within a range that was different in different blocks. The probability of the infrequent stimuli which were, in different blocks, either intensity deviants (600 Hz/70dB) or frequency deviants (650 Hz/80dB) was 10%. Both deviant stimuli elicited mismatch negativity even when the intensity of the frequent stimulus varied, although the amplitude of this component decreased with the increasing variability of the frequent stimulus. These results show that the generator process of mismatch negativity tolerates some variation in the repetitive stimulus, thus indicating that this process is also activated in ecologically more valid conditions. This is crucial to the interpretation of the generator process of mismatch negativity as a biologically vital warning mechanism.
The Cerebral Laterality of Mental Image Generation in Normal Subjects
Authors: Biggins Christie A. , Turetsky Bruce , Fein George
Published: February 2007

This research was an attempt to replicate and extend a published study that reported a left hemispheric locus for the generation of mental images. Several methodological problems were addressed, the stability of effects was assessed by repeating the experiment, and P300 latency was measured. A lateralized visual choice reaction time task was performed twice, once without the use of imagery and once with imagery. In each visual field, the use of imagery produced a speeding of reaction times when the target stimuli matched the image generated by the subject. A similar effect was present for P300 latency, and was still present in the reaction time data after partialling out the P300 latency effect. These results indicate that mental imagery can speed both stimulus evaluation and response processing. There was no difference in the amount of speeding for images in the two hemifields, providing no evidence for a preferential locus of mental image generation in either cerebral hemisphere.
Event‐Related Brain Potentials in Selective Listening to Frequent and Rare Stimuli
Authors: Alho Kimmo , Lavikainen Juha , Reinikainen Kalevi , Sams Mikko , Näätänen Risto
Published: February 2007

Our previous event‐related brain potential (ERP) results suggest that during selective listening, relevant stimuli are selected for further processing by comparing each stimulus to an “attentional trace,” a neuronal representation of the physical features of the relevant stimuli that distinguish them from the irrelevant stimuli. This comparison process is reflected by the early component of the processing negativity (PN), which is largest and longest to the relevant stimuli (perfectly matching with the trace). In the present study, the subjects selectively listened to designated tone stimuli which randomly appeared among irrelevant tones of a different pitch. The probability of relevant stimuli in a block was varied. The processing negativity elicited by relevant stimuli was smaller the less frequent they were. The results support the attentional‐trace theory of selective attention, which proposes that, in addition to active maintenance, the trace also depends on the rate of sensory reinforcement provided by the relevant stimuli.
Brain Generators Implicated in the Processing of Auditory Stimulus Deviance: A Topographic Event‐Related Potential Study
Authors: Giard Marie‐Hélène , Perrin François , Pernier Jacques , Bouchet Patrick
Published: February 2007

The neurophysiological mechanisms underlying mismatch negativity (MMN) can be inferred from an examination of some of the brain generators involved in the process of this event‐related potential (ERP) component. ERPs were recorded in two studies in which the subjects were involved in a selective dichotic listening task. Subjects were required to silently count rare stimuli deviating in pitch from a sequence of standard stimuli in one ear, while ignoring all the stimuli (standards and deviants) delivered randomly to the other ear. The results showed that, in all cases, the negative wave elicited by the deviant stimuli showed the highest amplitudes over the right hemiscalp irrespective of the ear of stimulation or the direction of attention. Scalp radial current density analysis showed that this asymmetric potential distribution could be attributed to the sum of activities of two sets of neural generators: one temporal, located in the vicinity of the primary auditory cortex, predominantly activated in the hemisphere contralateral to the ear of stimulation, and the other frontal, involving mainly the right hemisphere.

The results are discussed in light of Näätänen's model: we suggest the dissociation of two functional processes on the basis of activity of distinct brain areas: a sensory memory mechanism related to the temporal generators, and an automatic attention‐switching process related to the frontal generators.
Acute Emotional and Cardiovascular Effects of Stressful Mental Work During Aerobic Exercise
Authors: Roth David L. , Bachtler Shawn D. , Fillingim Roger B.
Published: February 2007

The acute effects of engaging in challenging mental work during a single session of aerobic exercise were examined on measures of subjective mood and cardiovascular function. Fifty‐seven female subjects were randomly assigned to participate in either a 10‐min aerobic exercise condition or a no‐exercise control condition. Half of the subjects in each group performed digits backward problems during this time period, and no mental stressors were presented to the other subjects. The results indicated that the exercise and mental stress conditions had additive effects on subjective anxiety levels and on cardiovascular responses during exercise. Both exercise and mental stress increased heart rate. In addition, exercise had anti‐anxiety and vasodilative effects, but both of these influences were attenuated by opposing main effects for mental stress exposure. No effects were found for exercise on measures of cardiovascular reactivity to a later digits backward stressor. The results are consistent with previous research in suggesting that exposure to mental stressors during aerobic exercise provides no acute psychological benefits but attenuates some of the mood improvements and vasodilative effects of the exercise activity.
The Processing of Temporal Intervals Reflected by CNV‐Like Brain Potentials
Authors: Elbert Thomas , Ulrich Rolf , Rockstroh Brigitte , Lutzenberger Werner
Published: February 2007

The present study employed event‐related potentials (ERPs) of the brain to improve the understanding of temporal processing. A reproduction paradigm was realized by presenting a visual stimulus (illuminated screen) for intervals of varying length. A few seconds after presentation of such standard intervals the visual stimulus was switched on again and subjects were asked to reproduce the duration of the standard interval by turning off the illumination after a corresponding interval had elapsed. The length of standard intervals varied randomly with each of the following lengths being presented 20 times: 1, 2, 3, 4, 6, and 8 s. Reproduction was accurate for standard intervals up to 3 s but deteriorated with increasing interval length. Brain potentials during reproduction intervals of 1–3 s differed from those recorded during the longer intervals. A CNV‐like slow negative shift developed during the shorter reproduction intervals. Negativity was reduced or even absent, when subjects had to reproduce standard intervals of 4 s or longer. The ERP results suggest that intervals shorter than 3–4 s may evoke a processing mode that is qualitatively different from the one dominating when periods in the range of several seconds have to be processed.
EEG Slow Wave Activity, REM Sleep, and Rectal Temperature During Night and Day Sleep in Morning‐Type and Evening‐Type Subjects
Authors: Kerkhof Gerard A. , Lancel Marike
Published: February 2007

During 3 baseline nights (2 for adaptation) and during 3 days of a sleep‐wake reversal, electrophysiological characteristics of sleep and rectal temperature were recorded in 8 morning‐type (M‐type) and 8 evening‐type (E‐type) subjects, living in a quiet sleep laboratory. Outcomes of visual sleep scoring revealed the following general tendencies for day‐sleep as compared to night‐sleep: shorter sleep latencies, shorter REM (rapid eye movement sleep) latencies, advance of the time of maximum REM duration, increased duration of slow wave sleep, more intermittent wakefulness, and decreased subjective sleep quality. Furthermore, for the M‐types consistently shorter sleep latencies and—for day‐sleep—longer REM latencies were observed than those for the E‐types. With regard to the parabolic time course of REM duration, M‐types appeared to be relatively phase advanced, in particular for their day‐sleep. In addition, subjective sleep quality was consistently higher for the M‐types, with the exception of the first day‐sleep. The temporal distributions of EEG delta (0.5–3.5 Hz) energy over the first four NREM/REM cycles of day‐sleep all deviated from a monotonically decreasing trend. Compared to night‐sleep the M‐types showed a relative increase of delta energy for Cycle 2, whereas for the E‐types a relative increase for Cycles 3 and 4 was observed. An analysis of delta energy, employing a pattern‐recognition technique independently from visual sleep scoring, revealed an overall faster rate of accumulation for the M‐types. Following sleep onset, rectal temperature showed a decrement, which was larger for the M‐types. Moreover, rectal temperature and delta energy were negatively related, as indicated by a negative mean intraindividual correlation. These results are discussed in relation to the characteristic sleep‐wake behavior of M‐types and E‐types.
The Effect of Repeated Testing on ERP Components During Auditory Selective Attention
Authors: Shelley Anne Marie , Ward Philip B. , Michie Patricia T. , Andrews Sally , Mitchell Penny F. , Catts Stanley V. , McConaghy Nathaniel
Published: February 2007

The present study examined long‐term repetition effects on human auditory event‐related potentials (ERPs). ERPs were recorded from subjects performing the same multidimensional auditory selective attention task on six separate occasions spaced one week apart. The task required subjects to attend to tones that varied along the dimensions of location (L), pitch (P), and duration (D) and to detect prespecified target (L+P+D+) combinations of these attributes. Processing negativity (PN) between 100–400 ms did not change in amplitude or onset latency as a function of repeated experience with the task. In contrast, two measures of “very late” PN were reduced with practice. Specifically, the location effect measured over the 400–700‐ms epoch was significant only for Weeks 1 and 2, and the separation of the L+P+D‐ ERP from other D‐ ERPs, measured over the 700–1000‐ms epoch, was significantly reduced from Week 1 to Week 2. A late negative component (700–1000 ms) elicited by correctly identified targets increased between Weeks 1 and 2, consistent with subjects adopting the strategy of rehearsal of the target itself rather than the L+P+D‐ standard. P2 amplitude increased significantly for all standards, possibly due to decreased latency jitter in later weeks. N1 latency became significantly shorter over weeks, reflecting either increasing confidence in stimulus discrimination with repeated testing or the overlapping of an unchanging N1 with an increasing P2.
Subjective and Objective Measures of Sleepiness: Effect of Benzodiazepine and Caffeine on Their Relationship
Authors: Johnson Laverne C. , Freeman Charles R. , Spinweber Cheryl L. , Gomez Steven A.
Published: February 2007

As part of a larger project on the effects of benzodiazepine and caffeine on daytime sleepiness, performance and mood, this study examined the relationship among the Multiple Sleep Latency Test, lapses during a tapping task, a Visual Analog Scale, and the Stanford Sleepiness scale. Subjects were 80 male, adult nonsmokers aged 20.3±2.7 years. The Multiple Sleep Latency Test, Stanford Sleepiness Scale, and the Visual Analog Scale were obtained at two‐hour intervals beginning at 0700 h and ending at 1700 h. The tapping task (lapses) was administered each day at 0600 h, 1000 h, and 1400 h. A lapse was a 3‐s or greater pause between taps. Correlations between the Multiple Sleep Latency Test and subjective (Visual Analog Scale and the Stanford Sleepiness Scale) measures were significant at 0600 h, but became nonsignificant as the day progressed. Correlations between lapses and the two subjective measures were generally nonsignificant. The two objective measures were significantly correlated in the total group but not in all treatment groups. The subjective measures were significantly correlated in the total sample and in each treatment group. This study reaffirms the importance of time of day when measuring sleepiness, and suggests that subjective and objective measures may measure different aspects of sleepiness.
Modulation of Slow Cortical Potentials by Instrumentally Learned Blood Pressure Responses
Authors: Elbert Thomas , Roberts Larry E. , Lutzenberger Werner , Birbaumer Niels
Published: February 2007

We assessed whether instrumentally‐learned pressor responses inhibit electrocortical acitivity, as predicted by learning theories of idiopathic hypertension. Subjects received beat‐by‐beat feedback for increases and decreases in mean arterial pressure measured from the finger (Peñáz method). Slow potentials were recorded from the midsagittal line during the final training session. Also recorded at this time were heart rate, eye movements, respiration, and post‐session verbal reports of the subject's control strategies. Thirteen of 14 subjects differentiated blood pressure increases and decreases at p<.05 or better during the final session (within‐subject discriminative operant procedure). Slow potentials were less negative on blood pressure increase compared to decrease trials at all midsagittal sites (p<.02), indicating relative cortical inhibition by pressor responses. This effect occurred even though subjects reported tensing of muscles on increase trials (p<.01), a behavioral activity previously associated with augmented rather than diminished cortical negativity. On increase trials slow potentials shifted toward positivity just prior to heart rate deceleration (the latter effect confirming activation of the baroreceptors).
Mismatch Detection and the Latency of Temporal Judgments
Authors: Novak Gerald , Ritter Walter , Vaughan Herbert G.
Published: February 2007

Event‐related potentials were recorded in two auditory tasks involving the discrimination of pitch or duration of binaurally presented tones. Frequently‐presented nontarget tones, when compared to the same tones in a simple reaction time task, elicited two negative peaks, NA1 and NA2, followed by a positive peak, nontarget positivity. Infrequently‐presented target tones, when compared to the nontargets, elicited mismatch negativity (MMN), followed by N2 and P3b. The peak latencies of NA1 and NA2 did not differ between the pitch and duration tasks, but the duration of NA1 and the peak latencies of mismatch negativity, N2, and P3b, as well as reaction time, increased in parallel for the duration task. It is proposed that the NA1‐nontarget positivity sequence reflects the initiation, maintenance, and termination of an attention‐modulated process, which is required for the performance of an auditory discrimination task, and that the MMN‐N2‐P3b sequence reflects a process elicited by infrequently‐presented targets, which is the main determinant of reaction time under these testing conditions.
Event‐Related Potentials and the Identification of Deviant Visual Stimuli
Authors: Czigler István , Csibra Gergely
Published: February 2007

The effects of deviant visual stimuli on event‐related potentials were investigated in a counting task (Experiment 1) and in a reaction time task (Experiment 2). In Experiment 2 the interstimulus interval was either short or long (340 vs. 1020 ms). The stimuli (two angles within a frame) were frequent (Standard) or deviant (differing from the Standard either in the orientation of the two angles, or in the thickness of the frame, or in both of these features). In various conditions the target stimuli were defined by one of the deviant features or by the conjunction of these features. Subjects were more accurate in the counting task, and the reaction time was shortest when the target feature was the deviant angle orientation. Performance was lowest for the conjunction of the deviant features. The deviant angle orientation elicited a posterior negative wave in the 140‐180 ms range. As the interstimulus interval increased, the magnitude of this component decreased. All stimuli with relevant (attended) deviant features elicited another posterior negative wave in the 180–260 ms range as well as an anterior positivity with similar latency. When the interstimulus interval was short, and the only target was the Conjunction Deviant, the summed occipital activity to the relevant features of deviant nontarget stimuli was larger than the negativity to the Conjunction Deviant. Target stimuli elicited late positive waves, which were sometimes preceded by central negativity.
The 24‐Hour Sleep Propensity Function: Experimental Bases for Somnotypology
Authors: Lavie Peretz , Zvuluni Amir
Published: February 2007

The present study investigated the temporal structure of sleep propensity during 48 hours using an ultrashort 7‐min sleep/13‐min wake cycle. Eight subjects were tested under two experimental conditions of either attempting sleep, or resisting sleep after a monitored night in the laboratory. Electrophysiological recordings were carried out during the 7‐min trials. The temporal structure and the overall level of sleepiness of the 48‐hour sleep propensity functions calculated from the amount of total sleep in each trial revealed a high within‐subjects stability. This was found both across the two days of the study within conditions, and across conditions. Also, diurnal levels of sleepiness were systematically related to nocturnal sleep parameters. Subjects having short nocturnal sleep latencies and higher sleep efficiencies slept more during the day. It is proposed that the structure and level of the sleep propensity function can be used to characterize individuals along two dimensions of somnotypology: “morningness‐eveningness” and “sleepy‐alert.”
Reliable responses to a cardiovascular reactivity protocol: A replication study in a biracial female sample
Authors: KAMARCK THOMAS W. , JENNINGS J. RICHARD , STEWART CHRISTOPHER J. , EDDY MICHAEL J.
Published: February 2007

This replication study was designed to examine the reliability of individual differences in cardiovascular responsivity to a standardized PC‐based cognitive task protocol (Kamarck et al., 1992) in a female community sample. Thirty women, both black and white (ages 25–44 years), were administered the protocol twice with a 1‐month retest interval using a mobile laboratory at a community‐based testing site. Measures of heart rate and blood pressure reactivity were obtained comparing assessments taken at rest and during three protocol tasks. Preejection period, stroke volume, and total peripheral resistance changes were estimated using impedance cardiography assessments. As in previous studies with males, individual differences in heart rate and systolic and diastolic blood pressure responses to the protocol were highly reliable (.80 or greater) when data were aggregated across three tasks and two testing sessions. Reliability of cardiac contractility (preejection period) and stroke volume changes to these tasks exceeded .70. This reactivity assessment procedure has now produced reliable results in three studies and appears to be exportable across diverse samples and settings.
Optimal digital filters for long‐latency components of the event‐related brain potential
Authors: FARWELL LAWRENCE A. , MARTINERIE JACQUES M. , BASHORE THEODORE R. , RAPP PAUL E. , GODDARD PHILIP H.
Published: February 2007

A fundamentally important problem for cognitive psychophysiologists is selection of the appropriate off‐line digital filter to extract signal from noise in the event‐related brain potential (ERP) recorded at the scalp. Investigators in the field typically use a type of finite impulse response (FIR) filter known as moving average or boxcar filter to achieve this end. However, this type of filter can produce significant amplitude diminution and distortion of the shape of the ERP waveform. Thus, there is a need to identify more appropriate filters. In this paper, we compare the performance of another type of FIR filter that, unlike the boxcar filler, is designed with an optimizing algorithm that reduces signal distortion and maximizes signal extraction (referred to here as an optimal FIR filter). We applied several different filters of both types to ERP data containing the P300 component. This comparison revealed that boxcar filters reduced the contribution of high‐frequency noise to the ERP but in so doing produced a substantial attenuation of P300 amplitude and, in some cases, substantial distortions of the shape of the waveform, resulting in significant errors in latency estimation. In contrast, the optimal FIR filters preserved P300 amplitude, morphology, and latency and also eliminated high‐frequency noise more effectively than did the boxcar filters. The implications of these results for data acquisition and analysis are discussed.
Effects of stimulus preexposure and intermodality change on electrodermal orienting
Authors: SIDDLE DAVID A. T. , LIPP OTTMAR V. , DALL PATRICIA J.
Published: February 2007

Previous research has indicated that an intermodality change trial presented after a habituation series elicits larger orienting responses than does the first stimulus of that series. Experiment 1 (N= 48) investigated whether this effect was still present if the change stimulus was not novel but was presented once prior to the habituation series. Two groups of subjects were presented with a series of 24 tones or vibrotactile stimuli. Trial 25 was an intermodality change test trial for half of the subjects in each group (change), whereas the remaining subjects received an additional habituation stimulus (no change). Prior to the habituation trials, each subject was exposed once to the test stimulus used in the change condition. Although response magnitude on the test trial was larger in the change condition than in the no‐change condition, test trial response magnitude did not exceed that on the first trial of the habituation series. In Experiment 2 (N= 84), one group was preexposed to the test stimulus, another was preexposed to an experimentally irrelevant stimulus, and a third received no stimulus prior to habituation training. Test trial response magnitude was larger than responses to the first stimulus of habituation in the change group that was not exposed to a stimulus prior to habituation but not in the preexposed groups. Preexposure to a stimulus prior to habituation training abolished the intermodality change effect even when the test stimulus was novel. The present results pose problems for noncomparator theories of habituation and support the notion that anticipatory processes are important in orienting and habituation.
Autonomic cardiac control. II. Noninvasive indices and basal response as revealed by autonomic blockades
Authors: CACIOPPO JOHN T. , BERNTSON GARY G. , BINKLEY PHILIP F. , QUIGLEY KAREN S. , UCHINO BERT N. , FIELDSTONE ANNETTE
Published: February 2007

Heart period, systolic time intervals, low and high frequency heart period variability, blood pressure, and respiration were measured in female subjects under three drug conditions (saline, atropine sulfate, metoprolol) while sitting and standing on three consecutive days. Following preinfusion baseline recordings, saline, metoprolol (14 mg), or atropine sulfate (2 mg) was infused for 15 min (by using a double‐blind procedure). Recordings were taken during a postinfusion baseline and in response to an orthostatic stressor (standing versus sitting postures). At the end of the metoprolol session, atropine sulfate was infused and responses were monitored during the post‐infusion (i.e., double blockade) baseline and during orthostatic stressor. Analyses of the blockade data revealed that the preejection period (PEP) reflected sympathetic but not vagal influences on the heart, and high frequency (HF, 0.12–0.40 Hz) heart rate variability (respiratory sinus arrhythmia) reflected vagal but not sympathetic influences on the heart. No other measure provided a specific index of the tonic sympathetic or vagal activation of the heart. Postinfusion PEP under saline predicted individual differences in postinfusion cardiac sympathetic activation, whereas postinfusion heart period (but not HF variability) under saline predicted individual differences in postinfusion cardiac vagal activation.
The effect of D‐amphetamine, clonidine, and yohimbine on human information processing
Authors: HALLIDAY ROY , NAYLOR HILARY , BRANDEIS DANIEL , CALLAWAY ENOCH , YANO LOVELLE , HERZIG KAREN
Published: February 2007

Twelve subjects were tested with D‐amphetamine, yohimbine, clonidine, and a placebo on a task with two levels of stimulus and two levels of response complexity. The purpose of this study was to test the hypothesis that noradrenergic durgs affect early stimulus processes. D‐amphetamine speeded reaction time (RT), clonidine slowed it, and yohimbine had no effect. D‐amphetamine and yohimbine decreased N1 latency and clonidine increased it. D‐amphetamine and yohimbine decreased P3 latency and clonidine increased it but, in each case, only when latency estimates were based on single trials, not on averages. D‐amphetamine's effect on RT, not P3, as measured by the average, is consistent with previous results. Single trial measures appear more sensitive. Speeding of N1 and single‐trial P3 data indicate that noradrenergic durgs affect processing of early (visual) information. D‐amphetamine's speeding of single‐trial P3 estimates was attributed to its noradrenergic actions. Yohimbine's speeding of P3 without changing RT is consistent with neural net (parallel) simulations but not with a serial model. These findings support the assumption that different neurotransmitters modulate specific cognitive processes.
The effect of monocular viewing on heartbeat discrimination
Authors: WEISZ JÜLIA , BALÁZS LÁSZLÓ , ÁDÁM GYÖRGY
Published: February 2007

In monocular viewing conditions, an activational imbalance between the cerebral hemispheres was assumed to develop, the direction of which depends on the side of the viewing eye. This assumption was based on the morphological differences between the nasal and the temporal hemiretinas and on physiological data. It was assumed that the hemisphere receiving visual information via the nasal optic fibers, that is, the hemisphere contralateral to the viewing eye, would be the more activated one. Because heart beat perception is regarded as a predominantly right hemispheric function, it was predicted that during right hemispheric activation created by left monocular viewing heartbeat discrimination performance would be better than during left hemispheric activation created by right monocular viewing. This hypothesis was tested on 30 male right‐handed university students who performed a Whitehead‐type heartbeat discrimination task while viewing only with the left or with the right eye. Heartbeat perception was more accurate when viewing with the left eye. Additionally, respiratory manipulation during heartbeat discrimination improved performance on this task.
Orienting in a defensive world: Mammalian modifications of our evolutionary heritage. A Polyvagal Theory
Authors: PORGES STEPHEN W.
Published: February 2007

The vagus, the 10th cranial nerve, contains pathways that contribute to the regulation of the internal viscera, including the heart. Vagal efferent fibers do not originate in a common brainstem structure. The Polyvagal Theory is introduced to explain the different functions of the two primary medullary source nuclei of the vagus: the nucleus ambiguus (NA) and the dorsal motor nucleus (DMNX). Although vagal pathways from both nuclei terminate on the sinoatrial node, it is argued that the fibers originating in NA are uniquely responsible for respiratory sinus arrhythmia (RSA). Divergent shifts in RSA and heart rate are explained by independent actions of DMNX and NA. The theory emphasizes a phylogenetic perspective and speculates that mammalian, but not reptilian, brainstem organization is characterized by a ventral vagal complex (including NA) related to processes associated with attention, motion, emotion, and communication. Various clinical disorders, such as sudden infant death syndrome and asthma, may be related to the competition between DMNX and NA.
Words and sentences: Event‐related brain potential measures
Authors: VAN PETTEN CYMA
Published: February 2007

Interactions between sentences and the individual words that comprise them are reviewed in studies using the event‐related brain potential (ERP). Results suggest that, for ambiguous words preceded by a biasing sentence context, context is used at an early stage to constrain the relevant sense of a word rather than select among multiple active senses. A study comparing associative single‐word context and sentence‐level context also suggests that sentence context influences the earliest stage of semantic analysis, but that the ability to use sentence context effectively is more demanding of working memory than the ability to use single‐word contexts. Another indication that sentence context has a dramatic effect on single‐word processing was the observation that high‐ and low‐frequency words elicit different ERPs at the beginnings of sentences but that this effect is suppressed by a meaningful sentence context.
Enhanced psychophysiological signs of attention after angiotensin‐converting enzyme inhibition by captopril
Authors: DERAD INGE , PIETROWSKY REINHARD , DODT CHRISTOPH , FEHM HORST L. , BORN JAN
Published: February 2007

Complementary to its essential role in the central nervous control of cardiovascular activity, the neuropeptide angiotensin 11 may regulate attentional processes. The present study evaluated central nervous, cardiovascular, and sympathetic indicators of attention after inhibition of angiotensin II synthesis by captopril (50 mg vs. placebo) in 14 men. Event‐related potentials (ERPs) and stimulus‐related electroencephalographic (EEG) activity were recorded while the subject performed an auditory oddball task. Captopril increased both the N1‐P2 component of the ERP (p < .05) and – following the first tone of the task – the EEG desynchronization in the lower alpha frequency band (p < .05). Although blood pressure remained unchanged, heart rate was lowered (p < .05) and plasma norepinephrine concentrations increased (p < .01) after captpril. The effects suggest that inhibition of angiotensin II synthesis enhances an attentional state typically present during sensory intake.
Processing of complex sounds in the human auditory cortex as revealed by magnetic brain responses
Authors: ALHO K. , TERVANIEMI M. , HUOTILAINEN M. , LAVIKAINEN J. , TIITINEN H. , ILMONIEMI R. J. , KNUUTILA J. , NÄÄTÄNEN R.
Published: February 2007

Processing of simple and complex sounds in the human brain was compared by recording extracranial magnetic mismatch responses (MMNm; the magnetic counterpart of the mismatch negativity, or MMN) to frequency changes in these sounds. Generator sources, modeled as equivalent current dipoles (ECDs), of MMNm responses to a change in one frequency element of complex sounds (a chord and a serial tone pattern) were located in supratemporal auditory cortex, on average, 10 mm medially to the source of an MMNm elicited by an identical frequency change in a simple tone. These results suggest that at least partially different supratemporal neuron populations are invovled in processing changes in simple and complex sounds and that sensory‐memory representations for these sounds may be located in different fields of the auditory cortex.
ERP modulations indicate the selective processing of visual stimuli as a result of transient and sustained spatial attention
Authors: Eimer Martin
Published: February 2007

Two experiments investigated selective processing as a result of transient and sustained visual‐spatial attention. In Experiment 1, attention was cued on a trial‐by‐trial basis and event‐related brain potentials were measured to stimuli preceded by valid, invalid, or neutral symbolic precues. Trial validity had only small effects on posterior PI and N1 components. At midline electrodes, an enhanced negativity for valid as compared with invalid trials was present, which appeared to reflect initial processing costs for invalid trials followed by an additional processing benefit for valid trials. Experiment 2 investigated whether these effects are specific for transient spatial attention by comparing transient and sustained attention conditions. No indication of early processing costs was found in the latter case.
Effects of task variables on measures of the mean onset latency of LRP depend on the scoring method
Authors: Smulders Fren T. Y. , Kenemans J. Leon , Kok Albert
Published: February 2007

The lateralized readiness potential (LRP) can be used to index the start of response activation, The onset of the average LRP can be computed as the latency at which the component starts to deviate significantly from zero or as the latency at which a certain proportion of its maximum amplitude is attained. The properties of both measures as estimates of the mean onset latency of the LRP were examined. Experiment I was a simulation study in which the mean onset latencies were known, Results indicated different types of bias for the two measures and greater reliability for a proportional measure. In Experiment 2, the sensitivity to bias, consistency, and linearity of both measures were evaluated in a set of empirical data. By all three criteria, a proportional onset measure was superior. It is recommended that the choice of the measure should depend on the hypothesis to he tested, so that conclusions are based on the more conservative test.
Human multiunit activity related to attention and preparatory set
Authors: KROPOTOV J. D. , ETLINGER S. C. , PONOMAREV V. A.
Published: February 2007

The impulse activity of 183 multiunits was recorded from the premotor cortex, the caudate nucleus, the globus pallidus, and the thalamus in 15 Parkinson's disease patients bearing inert gold electrodes implanted for diagnosis and therapy. The patients performed a task in which stimulus triplets (each consisting of two informational and one trigger stimulus) were presented. The patients initiated or inhibited actions (naming or counting) depending on the particular informational stimuli, thus allowing discrimination between different components of multiunit responses associated with attention and preparatory set and with disengagement from these states. The data indicate the existence of two overlapping circuits: one responsible for preparation for and assessment of the behavioral meaning of the stimulus and the other responsible for preparation for and performance of verbal action.