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PubMed1999

Essential functions of the human self model are implemented in the prefrontal cortex.

The human self model comprises essential features such as the experiences of ownership, of body-centered spatial perspectivity, and of a long-term unity of beliefs and attitudes. In the pathophysiology of schizophrenia, it is suggested that clinical subsyndromes like cognitive disorganization and derealization syndromes reflect disorders of this self model. These features are neurobiologically instantiated as an episodically active complex neural activation pattern and can be mapped to the brain, given adequate operationalizations of self model features. In its unique capability of integrating external and internal data, the prefrontal cortex (PFC) appears to be an essential component of the neuronal implementation of the self model. With close connections to other unimodal association cortices and to the limbic system, the PFC provides an internally represented world model and internal milieu data of the organism, both serving world orientation. In the pathophysiology of schizophrenia, it is the dysfunction of the PFC that is suggested to be the neural correlate for the different clinical schizophrenic subsyndromes. The pathophysiological study of psychiatric disorders may contribute to the theoretical debate on the neuronal basis of the self model.

Body Image↗

PubMed1996

Adaptive and intellectual functioning in autistic and nonautistic retarded children.

This study examined the relationship between adaptive functioning on the Vineland Adaptive Behaviour Scale (VABS) and intellectual functioning on the Stanford-Binet Intelligence Scale, 4th edition (SB-IV) in autistic children and nonautistic retarded children of comparable CA and SB-IV composite score (IQ). The autistic group had lower scores than the retarded group in VABS adaptive composite, Socialization domain, and Communication domain, and SB-IV Verbal Reasoning area. VABS domain scores yielded higher classification rates than the SB-IV area scores in discriminating the two groups. Correlations between the two measures were much higher for the autistic group than for the retarded group. Results support the conclusion that the cognitive impairment in autism is reflected in greater impairment in adaptive behaviors than in mental retardation without autism.

Autistic Disorder↗

PubMed2001

Modulation of saccadic eye movements by predicted reward outcome.

Reward is a primary goal of behavior and is crucial for survival of animals. To explore the mechanisms underlying such reward-oriented behavior, we devised a memory-guided saccade task in which only one fixed direction out of four was rewarded, which was called the one-direction-rewarded task (1DR). As the rewarded direction was changed in four blocks, saccades in a given direction were rewarded in one block (constituting reward-oriented behavior), but non-rewarded in the other blocks (non-reward-oriented behavior). As a control, an all-directions-rewarded task (ADR) was used. Using these tasks, we found that the parameters of saccades changed depending on whether or not the saccade was followed by reward. (1) The mean saccadic peak velocity was higher and the mean saccade latency was shorter in the rewarded condition than in the non-rewarded condition. (2) The mean saccade amplitude showed no difference in two out of three monkeys. (3) The variations of saccadic velocity, latency and amplitude were smaller in the rewarded condition. (4) Within a block of 1DR, the saccade velocity remained high in the rewarded condition, but decreased gradually in the non-rewarded condition; it decreased only slightly in ADR. The saccade latency showed the opposite pattern of change, but less clearly. (5) The saccades in the non-rewarded condition tended to have slower velocities and longer latencies in the trials shortly after a rewarded trial. (6) The ratio of error trials was much higher in the non-rewarded condition than the rewarded condition. (7) The errors, which were due to premature or incorrect saccades, showed unique spatiotemporal patterns that would reflect the competition between the cognitive and motivational processes. These results provide important constraints to the neuronal mechanism underlying reward-oriented behavior because it must satisfy these rules.

Animals↗

PubMed2002

Effects of delayed auditory feedback on timing of music performance.

Three experiments examined effects of delayed auditory feedback (DAF) on music performance as a function of the temporal location of feedback onsets within produced inter-onset intervals (IOIs). In Experiment 1, pianists performed isochronous melodies at two production rates with different amounts of DAF. Timing variability decreased for DAF amounts that caused feedback onsets to occur halfway through IOIs (binary subdivisions) in a 500-ms, but not 600-ms, IOI rate condition. In Experiment 2, pianists performed melodies with DAF delays and chose a preferred rate. Performers chose slower rates for larger delays; preferred rates approximated twice the amount of DAF. Experiment 3 tested the possibility that subjects deliberately conceptualized subdivisions in Experiments 1 and 2. Performers were given (1) no instructions, (2) instructions to mentally subdivide produced events in two, or (3) instructions to mentally subdivide produced events in three, in different blocks. Instructions to subdivide reduced timing variability for larger feedback delays. These experiments indicate that DAF disruption is reduced by subdividing instructions and sometimes by coincidences of feedback onsets with subdivisions of produced intervals. Such facilitation may reflect the use of hierarchical cognitive plans in production.

Auditory Perception↗

PubMed1990

Normal latency of the P300 event-related potential in mild-to-moderate Alzheimer's disease and depression.

A two-tone-discrimination task was used to elicit the P300 component of event-related (brain) potentials (ERPs) from patients with presumed Alzheimer's dementia of mild or moderate severity, depressed patients of older age, and cognitively normal individuals. Although the average P300 latency of the Alzheimer patients was greater than that of the depressed patients, which in turn was greater than that of older aged normals, none of the group differences in latency were statistically significant. Moreover, when latency was examined on an individual basis, less than one-quarter of the Alzheimer patients had an abnormally delayed P300 for their age. Reaction times and the percentage of correct behavioral responses to the tones did distinguish the Alzheimer from the normal group; on both measures the patients' scores were significantly worse. It was concluded that the performance of a simple tone discrimination task requiring a button-press response does not sufficiently tax those cognitive functions impaired in the earlier stages of Alzheimer's dementia to result in abnormally slowed cognitive processing of the kind reflected in P300 latency.

Aged↗

PubMed1990

Evoked potentials during REM sleep reflect dreaming.

Polygraphic recordings were collected for 11 normal subjects during sleep and wakefulness in order to investigate characteristics of the rapid eye movement (REM) associated potentials. EEGs were averaged using 5 different triggering points: (1) saccade onset under the normal ambient illumination, (2) saccade onset in the total darkness, (3) onset of REMs during REM sleep, (4) flash during REM sleep, and (5) flash during stage 2 sleep. In the central area, positive potentials appeared with waking saccades under the normal ambient illumination (P240L) and REMs (P185R). The latency of P185R associated with REMs was significantly shorter than that of P240L associated with waking saccades. These findings suggest that P185R is evoked by PGO waves occurring just before the REM. A small positive potential appeared in the occipital area with waking saccade under the normal ambient illumination (P260L) and REMs in the total darkness (P250R). Conspicuous absence of these waves for waking saccades in the total darkness suggests that P250R accompanied with REMs reflects activities involved with the cognitive processes occurring when a subject scans a dream image during REM sleep.

Adult↗

PubMedDate not supplied

Event-related EEG potentials in mild dementia of the Alzheimer type.

Most studies on event-related EEG potentials in dementia have focussed on the P3 component and used auditory stimuli only. In the present study, N2b was analysed in the usual auditory oddball task in addition to P3, and a visual task was employed ("Push"/"Wait"), with recordings including an occipital scalp site. Seven Alzheimer-type patients, with their mean IQ still in the normal range, were compared to age-matched normal controls. In the oddball task, P3 did not differ between groups but the patients' N2b was delayed. The main difference in the Push/Wait task was in an occipital P270, which component was distinctly larger in the patients. It is suggested that both differences reflect the disintegration of patients' cognition: stimuli are perceived in a normal way but then a gap arises due to uncertainty what to do with the perceived event.

Acoustic Stimulation↗

PubMed1995

Prediction of attitudes towards restrictive AIDS policies: a structural equation modelling approach.

The purpose of the study was to test a prehypothesized structural equation model of predictors of attitudes towards restrictive AIDS policies. It was assumed that such attitudes ae under influence of both cognitive processes and more general attitudinal structures. The hypothesized model was tested against empirical data from a nation-wide survey of Norwegian adults, including 543 males and 577 females. The proposed model fit the data reasonably well. As expressed by total effect education was the most important predictor of AIS policy attitudes. However, the most notable findings appeared to be the strong direct effect exerted by attitudes towards minorities. Misinformation about AIDS transmission and sexual attitudes also exerted significant direct effects upon AIDS policy attitudes. The results clearly demonstrate that AIDS policy attitudes are not cognitively based alone but also reflect more general attitudinal structures. Thus choosing a strategy which is primarily based on increasing the flow of factual AIDS information in order to remedy casual contact beliefs, will not be sufficient to prevent stigmatized and negative AIDS attitudes. This is more evident in that beliefs about modes of AIDS transmission, as reported in this study, seem themselves to have a symbolic component. A perspective which includes the idea of the value expressive functions of AIDS related attitudes seem relevant. Consequently, educational strategies which directly address prejudiced attitudes towards minority groups may prove particularly appropriate in the prevention of stigmatized and restrictive AIDS attitudes.

Acquired Immunodeficiency Syndrome↗

PubMed2006

Do obsessional beliefs discriminate OCD without tic patients from OCD with tic and Tourette's syndrome patients?

UNLABELLED: There is considerable overlap in symptomatology between Tourette's syndrome (TS) and obsessive-compulsive disorder (OCD). Increased rates of tics are found in OCD and up to 60% obsessive-compulsive symptoms in TS. However, in OCD obsessive-compulsive symptoms are more often anxiety-related and, as a consequence, aimed at anxiety-reduction, whereas in TS these symptoms are more stimulus-bound. Therefore, it is of clinical interest to study whether these phenomenological differences are reflected in differences between dysfunctional cognitions accompanying OC symptoms in OCD with or without tics and TS. Current cognitive theory of OCD ascertains that specific dysfunctional beliefs are important in the etiology and maintenance of OCD. To assess these beliefs, the obsessive-compulsive beliefs questionnaire-87 (OBQ-87) has been developed. In the present study, OBQ-87 scores of OCD patients without tics, OCD with tics, and TS (without OCD) patients were compared to those of normal controls. RESULTS: OCD without tic patients exhibited higher OBQ-87 scores than TS patients. No differences were found between OCD with or without tic patients on any of the OBQ-87 subscales. These results suggest that: (1) dysfunctional beliefs have no discriminative power with respect to OCD with or without tic patients; (2) the direct relationship between types of OC symptoms and specific dysfunctional beliefs is questionable. Therefore, one can doubt the specificity of cognitive theory of OCD to explain specific OC behavior.

Adult↗

PubMed2005

Neural correlates of the precedence effect in auditory evoked potentials.

The precedence effect in subjective localization tasks reflects the dominance of directional information of a direct sound (lead) over the information provided by one or several reflections (lags) for short delays. By collecting data of both psychoacoustical measurements and auditory evoked potentials the current study aims at neurophysiological correlates for the precedence effect in humans. In order to investigate whether the stimulus features or the perception of the stimulus is reflected on the ascending stages of the human auditory pathway, auditory brainstem responses (ABRs) as well as cortical auditory evoked potentials (CAEPs) using double click-pairs were recorded. Potentials were related to the results of the psychoacoustical data. ABRs to double click-pairs with lead-lag delays from 0 to 20 ms and interaural time differences (ITDs) in the lag click of 0 and 300 micros show an emerging second wave V for lead-lag delays larger than 2 ms. The amplitudes of the first and second wave V are the same for a lead-lag delay of about 5 ms. For the lag-ITD stimuli the latency of the second wave V was prolonged by approximately ITD/2 compared to the stimuli without lag-ITD. As the amplitudes of the second wave V were not decreased for a lead-lag delay around 5 ms as could be expected from psychoacoustical measurements of the precedence effect, ABRs reflect stimulus features rather than the perceptive qualities of the stimulus. The mismatch negativity (MMN) component of the CAEP for double click-pairs was determined using a diotic standard and a deviant with an ITD of 800 micros in the lag click. The comparison between the MMN components and the psychoacoustical data shows that the MMN is related to the perception of the stimulus, i.e., to the precedence effect. Generally, the findings of the present study suggest that the precedence effect is not a result of a poor sensitivity of the peripheral bottom-up processing. Rather, the precedence effect seems to be reflected by the MMN, i.e., cognitive processes on higher stages of the auditory pathway.

Acoustic Stimulation↗

PubMed2005

Mental and physical effort affect vigilance differently.

Both physical and mental effort are thought to affect vigilance. Mental effort is known for its vigilance declining effects, but the effects of physical effort are less clear. This study investigated whether these two forms of effort affect the EEG and subjective alertness differently. Participants performed a physical task and were subsequently presented with a mental task, or vice versa. Mental effort decreased subjective alertness and increased theta power in the EEG. Both results suggest a vigilance decline. Physical effort, however, increased subjective alertness and alpha and beta1 power in the EEG. These findings point towards an increase in vigilance. Beta2 power was reduced after physical effort, which may reflect a decrease in active cognitive processing. No transfer effects were found between the effort conditions, suggesting that the effects of mental and physical effort are distinct. It is concluded that mental effort decreases vigilance, whereas physical effort increases vigilance without improving subsequent task performance.

Adult↗

PubMed2005

Biological evidence for inheritance of exceptional longevity.

Subjects with exceptional longevity have a lower incidence and/or significant delay in the onset of age-related disease, and their family members may inherit biological factors that modulate aging processes and disease susceptibility. In a case control study, we aim to determine phenotype and genotype of exceptional longevity in a genetically homogenous population (Ashkenazi Jews), and their offspring, while an age-matched control group of Ashkenazi Jews was used as control groups. We demonstrated that exceptional longevity and healthy aging in humans is an inherited phenotype across three generations. Moreover, we demonstrated that subjects with exceptional longevity and their offspring have significantly larger high-density lipoprotein (HDL) levels and particle sizes and low-density lipoprotein (LDL) levels that reflect on their health and cognitive function performance. This phenotype have led us to study candidate genes involved in lipoprotein metabolism, and to the implication of homozygosity for the 405 valine (V) allele of cholesteryl ester transfer protein (CETP). A markedly higher frequency of a functional CETP variant that led to increased particle sizes of HDL and LDL and thus a better health performance is the first example of a phenotype and an associated genotype in humans with exceptional longevity. Hopefully, this line of research will lead us to establish which genotype is necessary (although not necessary sufficient) for a prolonged disease-free aging.

Age Factors↗

PubMed2005

Development of attentional networks: an fMRI study with children and adults.

Data on the development of the attentional systems remain scarce. We used structural and event-related functional magnetic resonance imaging to investigate differences in the neural mechanisms associated with alerting, reorienting, and executive control of attention between children (ages 8 to 12 years) and adults, while controlling for effects of performance and brain morphology. Behaviorally, children exhibited a numerically smaller alerting effect and significantly larger invalidity (reorienting) and interference (executive control of attention) effects. Neurally, children showed significantly reduced brain activation in a priori defined regions-of-interest in right-sided frontal-midbrain regions during alerting, in the right-sided temporo-parietal junction during reorienting of attention, and in the dorsolateral prefrontal cortex during executive control of attention. In addition, children activated significantly more brain regions outside the a priori defined regions-of-interest, such as the superior frontal gyrus during reorienting and the superior temporal gyrus during executive control of attention. Functional group differences overlapped with structural group differences in gray matter volume in particular within the frontopolar areas. The data suggest that there is a transition from functional yet immature systems supporting attentional functions in children to the more definitive adult networks and that the differences observed may reflect both developmental changes in cognitive strategies and morphology.

Adult↗

PubMed2005

Left mediotemporal structures mediate the retrieval of episodic autobiographical mental images.

The aim of this functional magnetic resonance imaging (fMRI) study was to investigate the neuroanatomical substrates associated with the process of mental generation of specific (i.e., exemplar) and episodic autobiographical (i.e., an image of a unique life episode connected with an object) images. The fMRI paradigm in this experiment included a non-image generation baseline and two activation conditions requiring the generation of either specific or episodic autobiographical images. Image generation times and brain activation were recorded. Behavioral results showed that generating specific mental images took significantly less than generating episodic autobiographical images. Individuals generated specific images that were well distinct from the episodic autobiographical ones, semantic in nature without an episodic reference. Episodic autobiographical images did not show a significant bias towards preferential retrieval from any particular life period but were retrieved from across the entire life span. Conjunction analysis of the fMRI data showed that the two image generation conditions significantly activated a common set of neural structures, including mediofrontal areas. This shared pattern of activation might be the result of an underlying similar format and characteristics (e.g., richness in details) between the two types of images and might reflect the involvement of similar cognitive processes. Distinct patterns of significant activation were also present. Activation in the right parietal regions, cuneus, precuneus and left temporal regions was associated solely with the generation of specific images. Regions more specifically devoted to episodic memory retrieval and imagery, such as the left parahippocampal gyrus and precuneus, and the posterior cingulate cortex bilaterally, were significantly activated exclusively by the generation of episodic autobiographical images.

Adult↗

PubMed2004

Long-term abstinence syndrome in heroin addicts: indices of P300 alterations associated with a short memory task.

Attentional deficits have been implicated in the pathophysiology of opioid addicts. The P300 component of event-related potentials (ERPs) is considered as a manifestation of attentional operations. The authors' goal was the comparison of P300 elicited during a short memory test between subjects with prolonged heroin abstinence and current heroin users as well as healthy controls. The P300 component was evaluated during the anticipatory period of a short memory task in 20 patients characterized by a past history of opioid dependence (6 months abstinence), in 18 current heroin users and in 20 healthy comparison subjects, matched for age, sex and educational level. Abstinent heroin addicts exhibited significant reduction of P300 amplitude at central frontal region, relative to the other two groups. The findings are discussed in connection to the aim of identifying psychophysiological indices, addressing issues in opioid use disorders, and suggest that knowledge about cognitive operations, such as those reflected by P300 component, could provide further insight into psychophysiological mechanisms underlying the long-term abstinence state of heroin addicts.

Acoustic Stimulation↗

PubMed2005

Functional changes in the activity of brain regions underlying emotion processing in the elderly.

Aging is associated with a decline in both cognitive and motor abilities that reflects deterioration of underlying brain circuitry. While age-related alterations have also been described in brain regions underlying emotional behavior (e.g., the amygdala), the functional consequence of such changes is less clear. To this end, we used blood oxygenation-level dependent (BOLD) functional magnetic resonance imaging (fMRI) to explore age-related changes in brain regions underlying emotion processing. Twelve young (age <30 years) and 14 elderly subjects (age >60 years) were studied with BOLD fMRI during a paradigm that involved perceptual processing of fearful and threatening stimuli. Consistent with previous reports, direct group comparisons revealed relatively increased BOLD fMRI responses in prefrontal cortical regions, including Broca's area, and relatively decreased responses in the amygdala and posterior fusiform gyri in elderly subjects. Importantly, additional analyses using an elderly-specific brain template for spatial normalization of the elderly BOLD fMRI data confirmed these divergent regional response patterns. While there was no difference between groups in accuracy on the task, elderly subjects were significantly slower (delayed reaction times) in performing the task. Our current data suggest that elderly subjects engage a more distributed neocortical network during the perceptual processing of emotional facial expressions. In light of recent converging data from two other studies, our observed effects may reflect age-related compensatory responses and/or alternative strategies in processing emotions, as the elderly appear to engage cognitive/linguistic systems in the context of reduced sensory and/or limbic responses.

Adult↗

PubMedDate not supplied

Alexithymia: relationship with ego defense and coping styles.

There is controversy in the literature as to whether alexithymia reflects a deficit in the cognitive processing of emotions or a defensive coping style. Previous studies with clinical populations reported a strong association between alexithymia and a maladaptive (immature) ego defense style. The present study was designed to examine this relationship in nonclinical populations, and also to explore the relationships between alexithymia and three general styles for coping with stressful situations. Sample 1, 287 nonclinical adults, completed the Twenty-Item Toronto Alexithymia Scale (TAS-20) and the Defense Style Questionnaire (DSQ). Sample 2, 83 undergraduate students who had been categorized previously into alexithymic and nonalexithymic subgroups, completed the DSQ and the Coping Inventory for Stressful Situations (CISS). In sample 1, the TAS-20 and its three factors were associated most strongly with an immature defense style, weakly with a neurotic defense style, and negatively with a mature defense style. In sample 2, alexithymic students scored significantly higher than nonalexithymic students on the immature and neurotic defense factors of the DSQ and significantly lower on the mature defense factor. Alexithymic students also scored significantly higher on the emotion-oriented coping scale and the distraction component of the avoidance-oriented coping scale of the CISS and significantly lower on the task-oriented coping scale. The results fail to support the view that alexithymia is an adaptive defense or coping style.

Adaptation, Psychological↗

PubMed1998

EEG coherence in Alzheimer's disease.

EEG coherence can be used to evaluate the functionality of cortical connections and to get information about the synchronization of the regional cortical activity. We studied EEG coherence in patients affected by clinically probable Alzheimer's disease (AD) in order to quantify the modifications in the cortico-cortical or cortico-subcortical connections. The EEGs were recorded in 10 AD patients (with mild or moderate degrees of dementia) and in 10 normal age-matched subjects, at rest and eye-closed, from 16 electrodes with linked-ears reference. Spectral parameters and coherence were calculated by a multichannel autoregressive model using 50 artifact-free epochs, 1 s duration each. Alpha coherence was significantly decreased in 6 patients, the decrease being more accentuated in the area near the electrode taken into account; a significant delta coherence increase was found in a few patients between frontal and posterior regions. The AD group showed a significant decrease of alpha band coherence, in particular in temporo-parieto-occipital areas, more evident in patients with a more severe cognitive impairment. These abnormalities could reflect two different pathophysiological changes: the alpha coherence decrease could be related to alterations in cortico-cortical connections, whereas the delta coherence increase could be related to the lack of influence of subcortical cholinergic structures on cortical electrical activity.

Aged↗