Biomedical subjects

M T Carrillo-de-la-Peña

Publications and source records attributed to M T Carrillo-de-la-Peña.

11 recordsLinked to original sources

PubMed2006

Intensity dependence of auditory-evoked cortical potentials in fibromyalgia patients: a test of the generalized hypervigilance hypothesis.

UNLABELLED: On the basis of recent evidence concerning the amplification of incoming stimulation in fibromyalgia (FM) patients, it has been proposed that a generalized hypervigilance of painful and nonpainful sensations may be at the root of this disorder. So far, research into this issue has been inconclusive, possibly owing to the lack of agreement as to the operational definition of "generalized hypervigilance" and to the lack of robust objective measures characterizing the sensory style of FM patients. In this study, we recorded auditory-evoked potentials (AEPs) elicited by tones of increasing intensity (60, 70, 80, 90, and 105 dB) in 27 female FM patients and 25 healthy controls. Fibromyalgia patients presented shorter N1 and P2 latencies and a stronger intensity dependence of their AEPs. Both results suggest that FM patients may be hypervigilant to sensory stimuli, especially when very loud tones are used. The most noteworthy difference between patients and control subjects is at the highest stimulus intensity, for which far more patients maintained increased N1-P2 amplitudes in relation to the 90-dB tones. The larger AEP amplitudes to the 105-dB tones suggest that defects in an inhibitory system protecting against overstimulation may be a crucial factor in the pathophysiology of FM. Because a stronger loudness dependence of AEPs has been related to weak serotonergic transmission, it is hypothesized that for many FM patients deficient inhibition of the response to noxious and intense auditory stimuli may be due to a serotonergic deficit. PERSPECTIVE: The study of auditory-evoked potentials in response to tones of increasing intensity in FM patients may help to clarify the pathophysiology of this disorder, especially regarding the role of inhibition deficits involving serotonergic dysfunction, and may be a useful tool to guide the pharmacologic treatment of FM patients.

Acoustic Stimulation↗

PubMed2006

Limb (hand vs. foot) and response conflict have similar effects on event-related potentials (ERPs) recorded during motor imagery and overt execution.

Although there is substantial evidence that motor execution (M-Ex) and motor imagery (M-Im) share a common neural substrate, the role of the primary motor cortex (M1) during imagery is still a matter of debate. The present ERP study tries to clarify the functional similarity between the two processes in respect of (i) the engagement of the corresponding somatotopic M1 areas during execution and imagery of hand vs. foot movements; and (ii) the effect of conflicting information on response preparation. To this end, we recorded ERPs from 28 electrode sites in 19 participants while they performed a conflict task with congruent (target and flanker arrowheads pointing in the same direction) and incongruent (target pointing in the opposite direction to the flanker arrowheads) trials. We obtained the lateralized readiness potential (LRP), a component generated in M1, while subjects physically executed or mentally simulated the task. As expected by the somatotopic organization of M1, the LRP was of opposite polarity when foot, rather than hand, movements were prepared. The inversion of polarity also occurred during M-Im, a result that strongly argues in favour of the participation of M1 in motor imagery. In incongruent trials, longer LRP latencies, a premature preparation of the incorrect response (positive deflection in LRP waveform) and a fronto-central N2 component associated with response conflict appeared during both M-Ex and M-Im. Altogether, the results support the functional equivalence of the two processes and give support to the clinical use of M-Im for the improvement and recovery of motor functions.

Adult↗

PubMed2001

One-year test-retest reliability of auditory evoked potentials (AEPs) to tones of increasing intensity.

The one-year reliability of auditory evoked potential (AEP) amplitude/stimulus intensity slopes (obtained for single channels and with dipole source analysis) and the stability and criterion validity of alternative measures to the conventional AEPs augmenting/reducing (A/R) linear slope were explored in a sample of 21 psychology students. AEPs were obtained from two sequences of 288 Ss of different intensities (60, 80, 90, and 110 dB SPL), presented in four blocks of 72 tones of each intensity or in a pseudorandomized order. The Zuckerman's Sensation Seeking Scale, which has been associated to the A/R slope, was used as a criterion measure. The results supported the one-year reliability of N1P2 slopes obtained in single channels (especially for Fz and Cz and for the random presentation of stimuli) and for dipoles obtained with brain electric source analysis (especially for the tangential dipoles). Neither of the A/R measures was significantly related to the criterion. These results support the stability of AEPs A/R, but throw serious doubts on the use of this psychophysiological phenomenon as a correlate of personality dimensions such as sensation seeking.

Acoustic Stimulation↗

PubMed2000

Loudness dependence of auditory evoked potentials in obsessive-compulsive disorder: a pilot study.

In recent years it has been suggested that a serotonergic dysfunction is involved in the pathogenesis of obsessive-compulsive disorder (OCD). The loudness dependence of auditory evoked potentials (AEPs) is one of the best validated indicators of the activity of the serotonin system in humans. To explore the validity of the hypothesis of a serotonergic dysfunction in OCD, the loudness dependence of AEPs of 22 medication-free OCD patients were compared with those of 22 age- and gender-matched healthy subjects. Auditory evoked N1/P2 activity to tones of increasing intensity was studied using dipole source analysis. Contrary to the hypothesis, OCD patients and healthy controls did not differ in their LDAEPs of the tangential dipole in particular, located in the primary auditory cortex and closely related to central serotonergic activity. Furthermore, no significant correlation was found between the severity of obsessive-compulsive or depressive symptoms and the loudness dependence of AEPs. These findings do not support the hypothesis of a serotonergic dysfunction in OCD patients.

Adult↗

PubMed2000

The effect of motivational instructions on P300 amplitude.

The aim of this investigation was to determine the effect on P300 amplitude of instructions aimed at increasing the subject's degree of task involvement. To this end, two different studies were carried out. In Study 1, 20 university students were tested with an auditory event-related potential (ERP) oddball paradigm (target: 1,100 Hz; standard: 1,000 Hz) in two consecutive runs, each with a different set of instructions; after the first run, subjects were verbally motivated to increase their level of performance in the second run. In Study 2 (performed 1 year later), ERPs were similarly obtained from the same subjects during two oddball runs, but this time both tests were preceded by neutral instructions. The amplitude and latency of N1 and P2 elicited by non-targets and of N2 and P3 in target waveforms were evaluated. The findings showed that following motivating instructions, P3 amplitude increased while P3 latency showed a non-significant decrease. The amplitude of P2 to non-target stimuli--which could be interpreted as P250--was also affected by the instructions provided. The overall results suggest that the presentation of motivating instructions is followed by a higher amount of attentional resources allocated to all stimuli, and a more efficient evaluation and discrimination of relevant targets. The implication of these findings for the clinical use of P300 has been discussed.

Acoustic Stimulation↗

PubMed1999

On the validity of interblock averaging of P300 in clinical settings.

The reduction of long-latency auditory ERPs amplitude, including P300, to repeated stimuli has been well documented in the literature on habituation. The effect of block repetition on auditory ERPs recorded for clinical purposes, where interblock intervals are commonly longer than those employed in habituation studies, was studied in a sample of 38 adults submitted to two blocks of a counting oddball paradigm. Four different experimental conditions were considered, differing in target probability, delivery or not of a previous passive oddball tone sequence, and the performance or not of other oddball tasks requiring more complex discriminative responses between the two blocks. Results showed that: (1) N1 amplitude to the frequent non-target stimuli decreased in the second block under all the conditions; (2) when the two blocks were consecutive (separated by 2-3 min), P300 amplitudes were unaffected by block repetition, this whatever the probability of the target (25% vs. 10%) and whether or not a passive oddball sequence preceded the two active blocks; (3) P300 amplitude was only affected by stimulus repetition in those subjects who performed more complex cognitive tasks between the first and second blocks and; (4) latency values were unaffected by repetition. It is hypothesised that the N1 amplitude decline may be caused by a decrease in alertness or arousal level produced by stimuli repetition. Reduction in P3 amplitude only appeared when more difficult tasks had to be done between the two oddball blocks and may reflect a decrease in the amount of attentional resources allocated to the second block, due either to fatigue or over training. The practice of using a grand average of several repetitions of the oddball paradigm, as recommended for the clinical use of long-latency ERPs, seems to be adequate provided that long interblock intervals are used and that the subject is not engaged in tasks requiring a high mental workload between the trial blocks.

Acoustic Stimulation↗

PubMed1999

Effects of intensity and order of stimuli presentation on AEPs: an analysis of the consistency of EP augmenting/reducing in the auditory modality.

OBJECTIVES: (1) To achieve a better understanding of the intensity dependence function of AEPs recorded at fronto-central and temporal electrode sites; (2) To assess the possible influence of the order of stimuli presentation on this function; and (3) To investigate if a subject's AEPs augmenting or reducing (A/R) tendency is consistent throughout two intra-session runs. METHODS: Two sequences of 288 stimuli of different intensities (60, 80, 90 and 110 dB SPL) were delivered to 29 psychology students. In the first run, stimuli were presented in 4 consecutive blocks of 72 tones of each intensity, either in an ascendant (from lowest to loudest stimuli) or descendent (from loudest to lowest) way. In the second run, a pseudo-randomized sequence of stimuli of the 4 intensities was presented. RESULTS: (1) AEPs recorded at fronto-central electrodes showed a stronger intensity dependence than those recorded at temporal leads; (2) The delivery of tones of different intensities in an aleatory sequence provoked higher amplitudes at Fz and Cz - especially for the loudest tones - but not at temporal leads; (3) The individual's AEP responses to stimuli of increasing intensity are highly consistent throughout two intra-session runs. CONCLUSIONS: The different findings obtained for the fronto-central N1P2 and the T complex in relation to the effect of intensity and order of stimuli presentation may be explained in terms of the cortical origin of those components. The higher amplitudes found with an aleatory sequence, especially for the highest intensity stimuli, may reflect that these stimuli capture the subject's attention and provoke an enhancement of the N1 component. The implications of the present results for investigation into A/R and the clinical relevance of this phenomenon are discussed.

Acoustic Stimulation↗

PubMed1994

A short-term longitudinal study of impulsivity and antisocial behavior.

This study analyzes the relationships between impulsivity and antisocial behavior in a noninstitutionalized sample, taking into account the multidimensional nature of impulsivity and the diversity of types of antisocial behavior. Data were obtained in 1989 and 1990 from 1,226 adolescents aged 12-18 years (583 boys and 643 girls) as part of a longitudinal study of risk factors for drug abuse and delinquency. The patterns of stability or change of the various dimensions of antisocial behavior (rule breaking, vandalism, theft, aggression, and drug taking) in relation to impulsivity were investigated. The results support that self-report measures of impulsivity are closely correlated with antisocial behavior among adolescents. The longitudinally oriented analysis of this work also shows that impulsivity is associated with a future increase in antisocial behavior.

Adolescent↗

PubMed1994

Time estimation and juvenile delinquency.

Certain empirical evidence suggests that subjects prone to delinquent activity may have faster internal clocks than others. To investigate the relationship between antisocial behavior and time perception and its dependence on the experimental time interval and method and on whether the subject is institutionalized we obtained verbal and production estimates of 5-, 15-, 30-, and 60-sec. intervals from 249 adolescents (156 school attenders and 93 institutionalized subjects) classified into 3 groups according to the intensity of their antisocial activity. Results provide no support for the hypothesis that overestimation of short time intervals is associated with either juvenile delinquency or institutionalization.

Adolescent↗

PubMed1993

Comparison among various methods of assessment of impulsiveness.

The current confused status of the research on impulsivity may be attributed to the lack of precise definitions, the reliance of most operationalizations on a single index, and inconsistency among different measures of the construct. Empirical measurements of impulsivity by self-reports, rating scales, or performance tasks suggest that the instruments employed measure aspects that have very little in common, a finding that throws serious doubts on the validity of the construct and implies a need for further research. To clarify this topic, we applied four different measures of impulsivity to 46 7th-grade (12 to 13 years old) schoolchildren. The children were rated by their teachers on an impulsivity behavior scale and were administered Kagan's Matching Familiar Figures Test, Version MFF-20, and two self-report forms, the Eysenck Impulsiveness Questionnaire, and the Barratt Impulsiveness Scale. Although the results confirmed the lack of convergence among these measures, high latencies on matching were associated with the cognitive aspect of the self-report scales. Treating impulsivity as a multidimensional construct is discussed.

Adolescent↗

PubMed1992

ERP augmenting/reducing and sensation seeking: a critical review.

Event-related potentials (ERPs) are generally considered capable of throwing light on the biological basis of personality traits. In particular, the ERP augmenting/reducing (A/R) phenomenon has been consistently associated with personality dimensions such as sensation seeking or impulsivity. However, doubts have been expressed regarding the validity of published evidence that individuals scoring high as sensation seekers are ERP augmenters. Reports of A/R-sensation seeking correlation in the opposite direction (in keeping with Petrie's hypotheses) threaten the construct validity of A/R, and lack of intermodal consistency throws serious doubts upon the existence of the central input-regulating mechanism once thought to be associated with sensation seeking. With the aim of clarification this article reviews the literature on the relationship between ERP A/R and sensation seeking, discusses the chief problems confronted by research in this area, and makes suggestions for future studies. It is concluded that experimental conditions of stimulus intensity and inter-stimulus interval may have played a part in the inconsistencies. The need to use a variety of measures of sensation seeking is stressed, and a number of other recommendations for research in this field are made.

Electroencephalography↗