bluuebunny/crossref_metadata_2025_split huggingface dataset:
Myoelectric and Force Feedback in the Facilitation of Isometric Strength Training: A Controlled Comparison
Authors: Cox Richard J. , Matyas Thomas A. 
Published: February 2007

ABSTRACTThree groups of 10 normal subjects were trained with 13 maximal isometric contractions on each of 8 days. During 8 of the 13 trials, subject groups received either myoelectric feedback (MFB), or force feedback (FFB), or no feedback. Over the 8 training days all groups increased EMG activity, but no significant group differences in rate of acquisition were obtained. All groups made gains in force over the 8 days. Force feedback produced better acquisition than either MFB or control conditions. However, both MFB and FFB produced comparable and significant differences between feedback and no‐feedback trials within a session, highlighting the importance of control group designs in the assessment of biofeedback effects. Dissociation between surface EMG and force was shown not only in the training effects, but also in the difference between feedback and no‐feedback performance within a session. An analysis of covariance revealed that during feedback trials MFB produced some EMG facilitation which could not be attributed to increased force production. This effect may have been due to selective reinforcement by MFB of co‐contraction in the extraneous musculature, or of changes in motor unit firing patterns. These phenomena may also account for the relative failure of MFB to facilitate force acquisition. A one‐month follow‐up showed significant retention following similar losses of force in all groups.
The Effects of Age and Prestimulus Duration upon Reflex Inhibition
Authors: Harbin Thomas J. , Keith Berg W. 
Published: February 2007

ABSTRACTReflex inhibition was investigated in young and elderly subjects as a function of prestimulus duration. In Experiment 1, tone prestimuli of 20 and 200 msec duration were presented at ISIs of 60, 120, 240, and 420 msec before the reflex‐eliciting, periorbital airpuff. Both age groups evidenced more eyeblink inhibition with the longer prestimulus. The heart rate response was primarily decelerative in both age groups. In young subjects, the initial deceleration was augmented by the prestimulus, particularly for the 200‐msec prestimulus, whereas the elderly heart rate response was unaffected. In Experiment 2, a gap in a continuous tone served as the prestimulus. In both young and elderly subjects, eyeblink inhibition increased as gap duration increased from 10 to 80 msec. The longest gap (120 msec) produced the most inhibition in the elderly, while inhibition decreased somewhat in young subjects between the 80 and 120 msec gaps. Heart rate was not affected by the gap prestimuli in either group. It was proposed that reflex inhibition is, in part, a function of the onset and offset transients of the prestimulus. As prestimulus duration is increased and, consequently, the two transients become more separated in time, their effects upon the reflex may become progressively more independent. The discrepancy between the PS effects upon eyeblink and HR in the elderly is probably due to a decline in HR response plasticity rather than central nervous system processes involved in reflex inhibition.
Effects of Stimulus Intensity on Cardiovascular Activity
Authors: Turpin Graham , Siddle David A. T. 
Published: February 2007

ABSTRACTA between‐groups design (N = 75) was employed to investigate the effects of stimulus intensity and repetition on cardiovascular activity. It was predicted that as intensity increased, the pattern of physiological activity would change, indicating a transition from the orienting to the defense reflex. Cardiovascular activity was represented by measures of heart rate, digital pulse amplitude, and cephalic blood content. Subjects received 12 presentations of a 1000 Hz tone of 45, 60, 75, 90, or 105 dB. Stimulus risetime was 30 msec and the duration 2 sec. Analyses of variance revealed reliable effects of intensity and repetition on all cardiovascular variables. However, neither these results nor additional multivariate analyses supported the differentiation of orienting and defense reflexes as suggested by Sokolov (1963) or Graham (1979). The importance of the startle reflex in the interpretation of these findings was discussed.
P300 Latency Correlates with Digit Span
Authors: Polich John , Howard Lawrence , Starr Arnold 
Published: February 2007

ABSTRACTP300 latency from a simple auditory discrimination counting task was obtained along with a digit span memory task for a large group of neurologically normal subjects. Moderate significant negative correlations between the peak latency of the P3a and P3b subcomponents and total memory score were found, although no relationship was observed for other waveform component latencies and memory score. The data suggest that the P300 component of the event‐related brain potential may index individual variations in memory ability.
Biological Rhythms in Arousal Indices: A Potential Confounding Effect in EEG Biofeedback
Authors: Gertz John , Lavie Peretz 
Published: February 2007

ABSTRACTSeveral investigators have observed ultradian rhythmicities in physiological indices of arousal. Although EEG biofeedback has been widely explored as a means of auto‐regulating cortical arousal, alpha or theta enhancement has not yet been convincingly demonstrated in comparison to continuous baseline controls for the possible effect of endogenous cyclical arousal trends. Diurnal EEG and subjectively appraised arousal measures were recorded from 11 subjects on a 5‐min recording, 5‐min recovery schedule, continuously over 7 1/2 hrs. Subjects returned to the laboratory for an equal amount of recording during which they attempted to either raise or lower the frequency of their EEG with the aid of biofeedback. Significant ultradian rhythmicity centered at about 200 min/cycle was observed in EEG measures and in subjectively appraised arousal. Although eyes‐open frequency‐raising and frequency‐lowering biofeedback training was efficacious in comparison to long‐day baselines, eyes‐closed frequency‐lowering training was not, lending support to other studies which have failed to achieve overall eyes‐closed alpha or theta enhancement even with many hours of training. Because the observed ultradian and circadian EEG rhythmicities could be spuriously interpreted as learning curves under a biofeedback paradigm, it is argued that future designs should incorporate continuous baseline controls.
T‐Wave Amplitude as an Index of Cardiac Sympathetic Activity: A Misleading Concept
Authors: Schwartz Peter J. , Weiss Theodore 
Published: February 2007

ABSTRACTT‐wave amplitude (TWA) appears unlikely to be a reliable index of myocardial sympathetic activity, at variance with what has previously been proposed. (1) TWA is not influenced consistently by stimulation or blockade of the cardiac sympathetic nerves. (2) Electrocardiographic lead selection can influence the direction and magnitude of change in TWA. (3) Sympathetic influences on the heart are exerted via alpha or beta receptors. While other non‐invasive indices (pre‐ejection period, pulse transit time) differentiate these effects, there is no evidence that TWA does. (4) Data on TWA derived from studies of patient populations may not be relevant to normal subjects. (5) Non‐neural factors can have important effects on TWA. We discourage further serious consideration of TWA as an index of myocardial sympathetic activity.
Cognitive Activity, Sleep Disturbance, and Stage Specific Differences Between Recorded and Reported Sleep
Authors: Coates Thomas J. , Killen Joel D. , Silverman Sheila , George June , Marchini Evelyn , Hamilton Stephanie , Thoresenz Carl E. 
Published: February 2007

ABSTRACTSleepers were studied in their homes to obtain measures of relationships between (a) discrepancies between reported and recorded sleep, (b) degree of sleep difficulty, and (e) reported cognitive activity. Twelve good sleepers and 12 insomniacs were questioned immediately after lights out, at the occurrence of the first sleep spindle or K‐complex, 10 min after the second sleep onset, 5 min after the onset of the first REM period, 10 min after the onset of the first stage 2, during subsequent periods of REM and stage 2 sleep, and at spontaneous arousals. Subjects responded to questions regarding mental content (thought vs picture, awake vs asleep, audience vs actor), estimated total time, and estimated total sleep time since the previous arousal. Insomniacs overestimated sleep difficulty only at 10 min after the second spindle and at spontaneous arousals. Reports of “picture” and “actor” were associated with sleeping difficulty. Persons who reported being “awake,”“actor,” and “picture” showed significantly greater discrepancies between reported and recorded sleep than persons who reported “sleep,”“audience,” or “thought”. The results are discussed in terms of implications for increased understanding of the phenomenon of insomnia.
Influence of Total Sleep Deprivation on Event‐Related Potentials in Man
Authors: Gauthier P. , Gottesmann C. 
Published: February 2007

ABSTRACTThe contingent negative variation (CNV) can be spontaneously followed in psychiatric patients by a postimperative negative variation (PINV), and also in normal subjects who have undergone sufficiently intense interference during the CNV paradigm. Our hypothesis was that sleep deprivation could facilitate the induction of a spontaneous PINV which would reflect a transient psychophysiological perturbation. The present experiment investigates the influence of total sleep deprivation on event‐related potentials (PINV, CNV, auditory evoked potential), behavioral performance (reaction time), and autonomic response (heart rate).Nineteen subjects participated in the experiment. The subjects were studied before and after 2 consecutive nights of total sleep deprivation. The event‐related potentials resulted from the summation of 16 trials. The warning stimulus (tone burst) was followed 1.5 sec later by an imperative stimulus (continuous tone) which was stopped by the subject. After the deprivation, 6 subjects underwent the CNV paradigm with interference.None of the subjects showed a PINV after sleep deprivation either spontaneously or with an interference which had induced it under non‐deprived conditions. The CNV and auditory evoked potential (AEP) amplitudes were reduced after the deprivation whereas AEP latencies increased. The unobtainable PINV after sleep deprivation and the low CNV amplitude could suggest a common neurophysiological origin for these two slow potentials.
Event‐Related Potential Correlates of Two Stages of Information Processing in Physical and Semantic Discrimination Tasks
Authors: Ritter Walter , Simson Richard , Vaughan Herbert G. 
Published: February 2007

ABSTRACTEvent‐related potentials were studied while subjects performed physical and semantic discrimination tasks. Two negative components, NA and N2, were observed in both kinds of discriminations. The earlier component, NA, had a constant onset latency, but its peak latency varied as a function of stimulus complexity. N2 latency varied in relation to changes in the peak of NA. RT and P3 followed N2 by similar amounts of time across tasks. The NA and N2 components were interpreted as reflecting partially overlapping sequential stages of processing associated with pattern recognition and stimulus classification, respectively.
Ambulatory Electrodermal Monitoring: Effects of Ambient Temperature, General Activity, Electrolyte Media, and Length of Recording
Authors: Turpin Graham , Shine Phil , Lader Malcolm 
Published: February 2007

ABSTRACTThe feasibility of long‐term monitoring of electrodermal activity (EDA) from freely moving subjects was assessed by examining several confounding variables including epidermal hydration, ambient temperature, and physical activity.EDA was monitored from 12 subjects during a normal working day. A portable 4 channel cassette recorder (Medilog) was employed to record skin conductance, ambient temperature, and arm movements.The effects of epidermal hydration were assessed using different 0.05 KCl electrolyte media. EDA was quantified throughout the day during several 5‐min rest periods and subsequent simple reaction time tasks. In order to distinguish between the influence of time of day and electrode/electrolyte aging, an extra pair of fresh electrodes was applied at each measurement period.Significant effects of temperature, electrolyte medium, and time of measurement on several indices of EDA were obtained. The implications of these data for long‐term ambulatory EDA monitoring were discussed.
Comparison of the Brener‐Jones and Whitehead Procedures for Assessing Cardiac Awareness
Authors: Jones Gary E. , O'Leary Roland T. , Pipkin Barry L. 
Published: February 2007

ABSTRACTThe similarities between the discrimination scores derived from the Brener‐Jones and Whitehead procedures for assessing cardiac awareness were examined. Subjects were provided with no performance feedback at any time, and were simply instructed to attend to afferent sensations of heartbeats. Twenty‐four male and female subjects were run under both procedures in a single session. Half of each gender were run in the order Brener‐Jones/Whitehead and half in the order Whitehead/Brener‐Jones. Subjects were given 50 trials of each procedure separated by a short rest interval. Three indices of discrimination were calculated for each procedure: number of correct calls, P(I), and 2 arcsin √P(A). Correlations between Brener‐Jones and Whitehead derived scores were weak and negative. Measures of physiological activity showed little indication of differential physiological arousal during or over trials.
Cardiovascular Feedback During Dynamic Exercise
Authors: Lo Chau R. , Johnston Derek W. 
Published: February 2007

ABSTRACTThe effects of verbal instructions, interbeat interval feedback, and feedback of the product of interbeat interval and pulse transit time in enabling subjects to decrease cardiovascular activity during exercise were studied in 36 healthy volunteers cycling a modified bicycle ergometer. During the 4 training sessions subjects given product feedback showed smaller decreases in interbeat interval and pulse transit time during exercise than did subjects receiving only verbal instructions. Subjects receiving interbeat interval feedback fell between the other two conditions. On the fifth session, during which feedback was not provided, no differences were found among the three conditions. The use of feedback of the product of interbeat interval and pulse transit time to control the sympathetic input to the heart and in the treatment of angina pectoris is discussed.
The Effects of a Restricted Sleep Regime on the Composition of Sleep and on Performance
Authors: Tilley Andrew J. , Wilkinson Robert T. 
Published: February 2007

ABSTRACTThis study examined the effects of restricting sleep to the first or second half of the night on the composition of sleep and on performance. Eight young women who regularly slept for 8–8.5 hrs a night had their sleep restricted to the first or second half of the night for two consecutive nights. Performance of a 20‐min unprepared simple reaction time task was measured at fixed times of day for the two restricted sleep conditions and for a full night sleep control condition. Restricting sleep to the second half of the night produced higher amounts of REM sleep and Stage 4 sleep and lower amounts of Stage 2 sleep compared to restricting sleep to the first half of the night. Both restricted sleep conditions impaired performance relative to the full night sleep control, and performance was worse after two nights of restricted sleep than after one night of restricted sleep. The results show that the effects of a restricted sleep regime on the composition of sleep are partly a function of the time of night to which sleep is restricted. It is suggested that the performance deficits are due to loss of sleep per se rather than due to any change in the composition of sleep.
Right Cerebral Activation in REM Sleep: Evidence from a Unilateral Tactile Recognition Test
Authors: Bertini Mario , Violani Cristiano , Zoccolotti Pierluigi , Antonelli Antonella , Di Stefano Lola 
Published: February 2007

ABSTRACTSeveral authors have advanced the hypothesis that the right cerebral hemisphere predominates during REM sleep. This hypothesis was tested by giving a newly‐devised unilateral tactile recognition test to 16 right‐handed male subjects during waking and upon awakenings from REM and NREM sleep.A two‐way analysis of variance revealed both a main effect for hand (the left hand being superior to the right) and a condition (waking‐REM‐NREM) X hand interaction. Consistent with the hypothesis of right‐hemisphere activation during REM, left‐hand superiority upon awakenings from REM was greater than that during waking; in the NREM condition, no between‐hand difference was observed. The latter result, as well as previous findings by Gordon, Frooman, and Lavie (1982), seems to point to the presence of left‐hemisphere activation during NREM and, more generally, to the link between hemispheric functional alternation and the REM‐NREM cycle.
Short‐Term Habituation and Dishabituation of the Mismatch Negativity of the ERP
Authors: Sams Mikko , Alho Kimmo , Näätänen Risto 
Published: February 2007

ABSTRACTStandard tones of 1000 Hz and deviant tones of 1250 Hz were presented in random order, 1 stimulus/second. The probabilities of the standards and deviants were 90% and 10%, respectively. In one condition the subject counted the deviant stimuli and in the other condition he/she read a comic book. ERPs were separately averaged to 1) the standard preceding the deviant, 2) the “first deviant” preceded by at least 4 standards, 3) the “second deviant” (an occasional deviant immediately following the “first deviant”), 4) the first and 5) the second standard following the “first deviant,” 6) the first and 7) the second standard following the “second deviant.” It was found that the mismatch negativity evoked in both conditions by the first deviant was considerably larger than to the second deviant. Also the first standard following the first deviant evoked the mismatch negativity. The results are discussed in terms of parallel neuronal models of the stimuli as reflected by the mismatch negativity.
Lucid, Prelucid, and Nonlucid Dreams Related to the Amount of EEG Alpha Activity during REM Sleep
Authors: Tyson Paul D. , Ogilvie Robert D. , Hunt Harry T. 
Published: February 2007

ABSTRACTAlpha activity during REM sleep without signs of awakening can discriminate between the blind classification of prelucid, lucid, and nonlucid dreams. Ten good dream recallers were aroused after relatively high or low amplitude REM alpha. The spectral and temporal characteristics of EEG alpha within each REM period were associated with lucidity and other content dimensions. Each type of dream had a reasonably distinct pattern of REM alpha. High amplitude alpha was found to be associated with prelucid dreams and bizarre content, which is consistent with theories of waking alpha activity and the hypothesis that lucidity sometimes emerges from prelucid experiences. The data are also consistent with the idea that lucidity is a viable dream content dimension, and interpreted in terms of systems theory imply that training which emphasizes dream content control may constrain the potential information integration function of lucid dreams.
The Relationship between Arterial Blood Pressure and Pulse Transit Time During Dynamic and Static Exercise
Authors: Marie G.V. , Lo C.R. , Van Jones J. , Johnston D.W. 
Published: February 2007

ABSTRACTThe relationships between arterial systolic and diastolic blood pressure (SBP and DBP), interbeat interval (IBI), and various pulse transit times were investigated in 5 young, healthy males during physical exercise and at rest. Transit times monitored were radial, brachial and dorsalis pedis RPIs (ECG R‐wave to pulse intervals), and brachial‐radial and radial‐dorsalis pedis PPIs (pulse to pulse intervals). Experimental sessions consisted of three periods: two involving mild dynamic exercise plus rests, and one involving static exercise (handgrips) plus rests. Correlation and regression analyses within period and subject were performed on individual beat data. Radial RPI was highly correlated with SBP (during dynamic periods, range −.57 to −.89, median r−.81; during static periods, range −.80 to −.88, median r=−.87) and moderately correlated with DBP (during dynamic periods, range −.10 to −.63, median r−.52; during static periods, range −.17 to −.77, median r−.66). Median correlations of radial RPI with SBP and DBP during exercise and rest separately were −.75 and −.40 (dynamic), −.79 and −.57 (static), and −.74 and −.26 (rest). The IBI X radial RPI product was very highly correlated with the rate‐pressure product (heart rate X SBP), an index of myocardial oxygen consumption (median r=−.96). The only PPI which reliably indexed SBP or DBP change was brachial‐radial PPI during the static exercise period (median r=−.86 and −.83).
A Comparison Between Commercially Available Electrode Gels and Purpose‐Made Gel, in the Measurement of Electrodermal Activity
Authors: Grey Susan J. , Smith Brian L. 
Published: February 2007

ABSTRACTDespite general agreement that a standardised procedure is desirable for the measurement of electrodermal activity, several types of electrode gel are in common use. In this study, 20 volunteers listened to a series of tones while skin conductance was measured at four sites using four different gels, namely K‐Y Jelly, Beckman, Neptic, and purpose‐made 0.05M NaCl in methyl cellulose. Prestimulus conductance level, response amplitude, change in conductance level, response latency, and response probability were measured. Analysis of variance showed a significant between‐gels effect for prestimulus conductance levels, with Beckman and Neptic giving higher levels than K‐Y Jelly or 0.05M, as predicted. There were no between‐gels effects for the other variables. There were no effects due to placements or channels. The results are discussed in relation to the theoretical requirements of electrode gels used for measuring electrodermal activity.
The Preparedness Theory of Phobias: The Effects of Initial Fear Level on Safety‐Signal Conditioning to Fear‐Relevant Stimuli
Authors: McNally Richard J. , Reiss Steven 
Published: February 2007

ABSTRACTThe preparedness theory of phobias implies that fear‐relevant stimuli are biologically contrapre‐pared for safety‐signal conditioning. Thus it should be very difficult to establish a pictorial snake as a safety‐signal predicting the absence of shock in a Pavlovian conditioned inhibition paradigm. Since this contrapreparedness is postulated as species‐wide, the snake stimulus should be an ineffective safety‐signal even in those subjects who do not fear snakes. In contrast, the prior fear hypothesis suggests that this difficulty should occur only in those subjects who already fear snakes. To test these hypotheses, subjects reporting either high or low snake fear were exposed to electrodermal conditioning trials designed to establish a fear‐relevant CS (a pictorial snake) and a fear‐irrelevant CS (a pictorial flower) as safety‐signals by nonreinforcing each in compound with a fear‐eliciting CS. The results provided marginal support for the prior fear hypothesis.