Personality and sex differences in emotional responsiveness to positive and negative cognitive stimuli

To investigate the influence of psychoticism (P) and neuroticism (N) on emotional responding, a re-analysis was carried out on subjective and physiological data collected while Ss (n = 50) repeatedly imagined anxious (intrusive) or depressive, and pleasant thoughts or images. High N was associated with a greater negative mood state subsequent to imagining the distressing cognitive stimuli, though there was no relation with physiological reactivity. However, high P scorers did evidence less overall cardiac reactivity and, to a lesser extent, fewer skin resistance responses than low P Ss. The results are discussed in light of the moderating influence that stimulus and response characteristics as well as gender differences can have on the interaction between personality traits and emotional responding.     

Visual evoked potential augmenting/reducing slopes in cats—1. Reliability as a function of flash intensity range

A cat model for the study of individual differences in augmenting/reducing of the visual evoked potential (VEP) is proposed. Multiple VEP sessions over an extended time period of 20 months permitted analysis of the stability of VEP amplitudes and augmenting/reducing slopes. The VEP was found to have a stable shape at a given intensity and served as a unique individual signature for each cat. Three intensity ranges (low, 0.2–15 lumens/m²/sterrad. sec; medium, 1–1501/m²/sr. s; and high, 20–1500 1/m²/sr.s), and four early components of the VEP (P1, N1, P2 and N2) were studied. A cortical inhibitory threshold was reached for most cats in the medium range of intensities. However, VEP amplitudes were variable, and only the N1 and P1 − N1 components at the medium range of intensities yielded reliable augmenting/reducing slopes. Averaging slopes of individual runs improved reliability, and the average N1 amplitude slopes for each of 3 sessions at the medium range of intensities correlated at r#62;0.9.     

时间分配的执行功能:双重效价联合任务的证据

采用内隐联想测验的修订版本双重效价联合任务范式,利用ERP技术探究不同时间分配倾向个体在执行冲突和转换任务时的执行功能,以揭示不同时间分配倾向个体在相容和不相容任务过程中脑内时程的动态变化。研究结果发现,多重组个体显示出更快的反应时;ERP结果表明,相比于多重组,单一组在不相容任务中比在相容任务中诱发了更大的N170,说明多重组个体可能更善于同时执行多项任务,而单一组执行冲突任务可能需要投入更多的注意资源。同时在认知加工的晚期阶段单一组比多重组诱发了更大的LPP,提示单一组需要更强的认知控制加工。     

轻度认知功能障碍患者工作记忆中 脑电能量及皮质联络功能的变化特征

探讨轻度认知功能障碍患者（MCI）工作记忆状态下脑电能量及皮质联络功能的变化特征。被试为从社区选取的35名轻度认知功能障碍患者和34名健康志愿者。采用简单计算回忆方法,结果发现工作记忆加工过程中会引起4.0~18.0Hz范围内功率值的改变,且MCI组高于正常对照组;MCI患者在中央、顶、颞叶的半球间相干系数均显著高于正常对照组。研究结果提示MCI患者可能存在中央、顶、颞叶皮层的功能减退,工作记忆状态下通过代偿机制仍能维持加工的有效性     

Stimulus complexity, EEG abundance gradients, and detection efficiency in a visual recognition task.

Occipital EEG was monitored while subjects inspected 27 projected patterns. The number (N) and variety (V) of elements in the patterns were varied systematically. There were three levels of N (6, 12 or 24 elements) and three levels of V (circles, squares or hexagons occupying all, one half or one third of the element locations for all levels of N). Subjects were instructed that they would be required in a post-test to recognize the patterns, among patterns which had not appeared; they were also informed that the patterns had been constructed according to a set of simple rules, but the nature of these rules was not made fully explicit. The EEG was quantified by means of low-frequency analysis, yielding measures of abundance (theta, alpha and beta) and mean dominant frequency. For the recognition task, nine stimulus items were embedded among 45 items. Recognition efficiency was measured by means of the signal detection theory discrimination index (d'). The results were as follows: (i) Both N and V were inversely related to alpha abundance (P less than 0-01); (ii) the strongest relationship between stimulus parameters and the EEG held for N and EEG beta activity (13-5-19-5 Hz;P less than 0-001), where again the EEG and N were inversely related; (iii) there was a significant (P less than 0-05) direct relationship between N and theta activity; (iv) contrary to prediction, mean dominant alpha frequency decreased as N increased; (v) d' correlated significantly with a number of effects for N, i.e. subjects who exhibited greatest EEG discriminability of items during exposure of the patterns, subsequently obtained the higher detection scores in the recognition task. The work described therefore demonstrates that only only do stimulus parameters have systematic effects upon brain activity as measured by the EEG, but that such effects have functional value and reflect aspects of efficiency. The results are fully compatible with arousal theory constructs relating physiological reactivity and performance.     

Modification of EEG power spectra and EEG connectivity in autobiographical memory: a sLORETA study

The aim of the present study was to explore the modifications of scalp EEG power spectra and EEG connectivity during the autobiographical memory test (AM-T) and during the retrieval of an autobiographical event (the high school final examination, Task 2). Seventeen healthy volunteers were enrolled (9 women and 8 men, mean age 23.4 ± 2.8 years, range 19–30). EEG was recorded at baseline and while performing the autobiographical memory (AM) tasks, by means of 19 surface electrodes and a nasopharyngeal electrode. EEG analysis was conducted by means of the standardized LOw Resolution Electric Tomography (sLORETA) software. Power spectra and lagged EEG coherence were compared between EEG acquired during the memory tasks and baseline recording. The frequency bands considered were as follows: delta (0.5–4 Hz); theta (4.5–7.5 Hz); alpha (8–12.5 Hz); beta1 (13–17.5 Hz); beta2 (18–30 Hz); gamma (30.5–60 Hz). During AM-T, we observed a significant delta power increase in left frontal and midline cortices (T = 3.554; p < 0.05) and increased EEG connectivity in delta band in prefrontal, temporal, parietal, and occipital areas, and for gamma bands in the left temporo-parietal regions (T = 4.154; p < 0.05). In Task 2, we measured an increased power in the gamma band located in the left posterior midline areas (T = 3.960; p < 0.05) and a significant increase in delta band connectivity in the prefrontal, temporal, parietal, and occipital areas, and in the gamma band involving right temporo-parietal areas (T = 4.579; p < 0.05). These results indicate that AM retrieval engages in a complex network which is mediated by both low- (delta) and high-frequency (gamma) EEG bands.     

Attention and Brain Activity While Watching Television: Components of Viewer Engagement

Television commercials include elements designed to engage the viewer's attention. Manipulations of the commercial's visual structure that result in rapid pacing or frequent scene changes can be engaging because they require a frequent redirection of visual attention. Manipulations of semantic content through such techniques as the inclusion of humorous or anomalous elements can elicit cognitive engagement. Structural manipulations in videos are known to attenuate the alpha (8 to 13 Hz) rhythm of the electroencephalogram (EEG) recorded over posterior cortical regions involved with visual processes. To examine whether other engaging elements also affect the alpha rhythm, EEG was recorded from 10 participants who viewed television commercials. Principal components analysis was used to decompose the alpha rhythm into underlying factors that varied in spatial topography over the head and in spectral composition. Across commercials, the power of a posterior-distributed alpha component was inversely correlated with the frequency of scene changes. In contrast, a frontal component in the lower frequency portion of the alpha band was attenuated during commercials that elicited high subjective interest, independent of scene change frequency. And, an upper-frequency frontal alpha component was attenuated during commercials for which the item being advertised had a high probability of being subsequently recalled, independent of other factors. These frontal patterns of alpha reactivity are consistent with other neuroimaging results concerning frontal lobe activation by executive processes and episodic memory encoding. With appropriate neurologically guided analysis, EEG signals can provide a unique means of monitoring both perceptual and higher order neurocognitive processes during television viewing.     

A study of personality variation in women before and after menstruation

The present study was conducted to investigate variations in the personality of women during their premenstrual and postmenstrual periods. PEN and TMAS tests were administered to 25 women (16 unmarried and 9 married) in the age range of 20–30 yr. The study was conducted in two phases, premenstrual and postmenstrual, on the same Ss. The ‘t’-ratios for correlated means were computed to study the differences in personality in the two phases. The results revealed significant differences between premenstrual and postmenstrual P, N and Anxiety scores. The scores on these personality dimensions increased significantly during the premenstrual period.     

Longitudinal study of perception of structured optic flow and random visual motion in infants using high‐density EEG

Electroencephalogram (EEG) was used in infants at 3–4 months and 11–12 months to longitudinally study brain electrical activity as the infants were exposed to structured forwards and reversed optic flow, and non‐structured random visual motion. Analyses of visual evoked potential (VEP) and temporal spectral evolution (TSE, time‐dependent amplitude changes) were performed on EEG data recorded with a 128‐channel sensor array. VEP results showed infants to significantly differentiate between the radial motion conditions, but only at 11–12 months where they showed shortest latency for forwards optic flow and longest latency for random visual motion. When the TSE results of the motion conditions were compared with those of a static non‐flow dot pattern, infants at 3–4 and 11–12 months both showed significant differences in induced activity. A decrease in amplitudes at 5–7 Hz was observed as desynchronized theta‐band activity at both 3–4 and 11–12 months, while an increase in amplitudes at 9–13 Hz was observed as synchronized alpha‐band activity only at 11–12 months. It was concluded that brain electrical activities related to visual motion perception change during the first year of life, and these changes can be observed both in the VEP and induced activities of EEG. With adequate neurobiological development and locomotor experience infants around 1 year of age rely, more so than when they were younger, on structured optic flow and show a more adult‐like specialization for motion where faster oscillating cell assemblies have fewer but more specialized neurons, resulting in improved visual motion perception.     

Mechanisms behind hazard perception of warning signs: An EEG study

Warning signs are the most effective way to alert people to hazards in the industries, architecture, and transportation. To better understand how these warning signs prompted hazard, this study investigated the intrinsic mechanism of hazard perception of warning signs, including warning words (low versus high hazard levels) and surrounding shapes (upright triangle versus circle). We recruited 18 participants and recorded electroencephalogram (EEG). We found that a combination of high-hazard-level words and an upright triangle shape significantly elicited more negative N300 and increased theta-band (3–8 Hz) synchronization, but reduced beta-band (15–30 Hz) desynchronization. The N300 component represented the emotional arousal strength, theta oscillations reflected the engagement of retrieval of emotional experiences from episodic memory, and beta oscillation connoted the semantic encoding. Thus, these findings suggested that a high-hazard-level combination had the ability to obtain high priority in cognitive processing. The EEG pattern changes allowed us to assess whether the hazard perception of warning signs was high or low, which could be an accurate indicator to better evaluate the design of warning signs.     

Lack of the metabotropic glutamate receptor subtype 7 selectively modulates Theta rhythm and working memory

Metabotropic glutamate receptors (mGluRs) are known to play a role in synaptic plasticity and learning. We have previously shown that mGluR7 deletion in mice produces a selective working memory (WM) impairment, while other types of memory such as reference memory remain unaffected. Since WM has been associated with Theta activity (6-12 Hz) in EEGs, and since EEG abnormalities have been observed in these mice before, we studied the effect of mGluR7 gene ablation on EEG activity in the hippocampus, in particular in the Theta range, during performance of a WM task. In an eight-arm maze with four arms baited, mGluR7 knock-out (KO) and wild-type mice committed the same number of reference memory errors, whereas KOs committed more WM errors. While performing the task, KO mice showed substantially higher Theta amplitudes, and the ratio of Theta to overall EEG power was much increased. No change was seen in the Delta (0-5 Hz), or Gamma (30-40 Hz) EEG bands compared with controls. When recording EEGs during periods of rest in the home cages, no difference was seen between groups. These findings suggest that mGluR7 is important for modulation and control of Theta activity. Since only WM was affected, and only the Theta range of EEG activity was altered, these results show a correlation between Theta rhythm and WM performance, and therefore support the concept that Theta activity in the hippocampus is involved in WM storage.     

Electrocortical signs of arousal in response to darkness and the assessment of type A behavior in professional drivers with and without cardiovascular disease

Background and Aims  In night driving, the fatal accident rate is about four times that in daytime. There is a lack of published studies of the effect of darkness on electrocortical responses in professional drivers (PD). Aim: Assessing relations between electroencephalographic (EEG) reactions to enforced darkness reminiscent of night driving, and untoward behavioral response patterns, notably Type A behavior. Methods  PD: 13 with ischemic heart disease, 12 hypertensives (HTN), 10 borderline hypertensives and 34 normotensives, and 23 non-PD controls. Five minutes of electroencephalographic recording with eyes closed, and subsequently 3 minutes exposure to darkness. EEG parameters were: alpha abundance, amplitude and frequent. Type A behavior (TAB) was assessed by observation and by questionnaire. Results  Alpha abundance diminished significantly for darkness compared to spontaneous recording for all groups. No between-group differences were found for EEG. There were no significant differences in EEG between drivers with IHD or HTN taking versus not taking centrally active β-blockers. Drivers with IHD were the only group to show significant increase in dominant α frequency at darkness. The IHD group also had the highest TAB questionnaire scores and the heaviest exposure to professional driving. Type A scores were significantly correlated with dominantt alpha frequency during darkness. Low availability of attachment and special driving hazards best predicted TAB scores in driven. There was a significance between group difference with respect to Symbolic Aversiveness at the work place comparing each driver group with the non-PD control group. Conclusions  Exposure to darkness reminiscent of night driving can elicit central arousal, in conflict with circadian rhythm, and in combination with other driving hazards which contribute to symbolic aversiveness, the essence of driving. And low availability of social attachment could contribute to sustained, and in turn to the development of Type A behavior in professional drivers.     

Correlation between evening and morning waking EEG and spatial orientation

The prefrontal, frontal, and parietal EEG of 16 healthy young adults (seven men, nine women; age=22.57+/-4.2) was recorded during the waking state (eyes closed) in the evening before and the morning following a second consecutive night spent in a sleep laboratory. Following the morning EEG recording session, participants were tested in a human-size maze upon five learning trials of a four-intersection route. Results on the fifth trial served as the learning index. We found a significant positive correlation between time taken to carry out the route and prefrontal, frontal EEG alpha-2 (10.0-12.75 Hz), and sigma (11.5-14.5 Hz) frequency bands. We also found that prefrontal and frontal theta activity correlated negatively with number of errors. No correlation was found between performance and neither alpha-1 (8.0-9.75 Hz) nor parietal EEG activity. These results confirm the involvement of the prefrontal and frontal cortices in the mechanisms responsible for modulating spatial orientation.     

How brain arousal systems determine different temperament types and the major dimensions of personality

Theory and research is described which led to the hypothesis that the choleric (E+N+) and melancholic (E−N+) temperaments are determined by differences in thalamocortical inhibition of brain-stem processes. An opportunity to test this hypothesis was provided by the recent discovery of 4, 7, and 10 Hz response waves confounded in EEG averaged evoked potentials [Robinson, D. L. (1999b). The technical, neurological, and psychological significance of ‘alpha’ ‘theta’ and ‘delta’ waves confounded in EEG evoked potentials: 1. A study of peak latencies. Electroencephalography and Clinical Neurophysiology, 110, 1427–1434; (2000). The technical neurological, and psychological significance of ‘alpha’, ‘delta’, and ‘theta’ waves confounded in EEG evoked potentials: A study of peak amplitudes. Personality and Individual Differences, 28, 673–693]. These responses are attributed to the brain-stem, limbic, and thalamocortical arousal systems, respectively, and in the cited reports principal components analysis of data obtained from 93 participants confirmed the existence of predicted excitatory and inhibitory relationships. ANOVA was used in the present study to test the further prediction that there should be strong inhibition of the 4 Hz system by the 10 Hz system in melancholics (E−N+) and weak inhibition of the 4 Hz system in cholerics (E+N+), with median inhibition predicted for the other temperament types. There was a large and statistically significant difference between the mean scores on the PCA inhibition factor obtained for the temperament groups, with temperament defined in terms of high and low EPQ extraversion (E) and neuroticism (N) scores. The significance of these results is discussed with reference to fundamental questions raised by Pavlov's pioneering research but left unanswered for the best part of a century. Implications for the future conduct of personality research are also considered.     

Visual evoked potentials elicited by subjective contour figures

In order to investigate the relationship between the appearance of illusory figures and the wave form of visual evoked potentials (VEPs), 8 different visual pattern stimuli were presented to 8 normal subjects. Four of the stimuli (experimental stimuli) produced subjective figures and contours (squares and discs). The 4 other stimuli (reference stimuli), although equal to the experimental stimuli in the amount of physical energy, did not produce the illusion of squares or discs. Electrodes were placed on the scalp at central and occipital locations. Three prominent peaks in the occipital record were observed in all subjects. An amplitude difference of VEP N180 (N2) between the subjective figures and the reference stimuli was found in the values for each subject. Enhancement of the VEP of the illusory figure stimuli was observed for a specific component (N2), whereas the amplitude values at the central components and the occipital P120 (P2) and P280 (P3) were almost the same as the reference values. The VEP (N2 component) amplitude enhancement at the occipital area for subjective figure stimuli suggests that illusory contour formation takes place at higher levels in the visual system. This was known from experiments using dichoptic presentation.     

Implicit activation of alcohol concepts by negative affective cues distinguishes between problem drinkers with high and low psychiatric distress.

This study tested the hypothesis that negative affective (NEG) cues activate alcohol concepts more strongly in problem drinkers with high rather than low psychiatric distress (PD) and that a parallel difference applies to activation of NEG concepts by alcohol cues. A lexical decision task assessed memory activation in 36 problem drinkers with high vs. low scores on the Symptom Checklist-90. High PD drinkers displayed activation in each condition; low PD drinkers displayed inhibition. Activation of alcohol concepts by NEG cues correlated with intensity of PD, bias to drink in NEG states, and confidence to avoid drinking in these states. Results corroborate in vivo cue reactivity studies and indicate a functional difference between problem drinkers with high and low PD.     

Event-related EEG oscillations to semantically unrelated words in normal and learning disabled children

Learning disabilities (LD) are one of the most frequent problems for elementary school-aged children. In this paper, event-related EEG oscillations to semantically related and unrelated pairs of words were studied in a group of 18 children with LD not otherwise specified (LD-NOS) and in 16 children with normal academic achievement. We propose that EEG oscillations may be different in LD NOS children versus normal control children that may explain some of the deficits observed in the LD-NOS group. The EEGs were recorded using the 10/20 system. EEG segments were edited by visual inspection 1000ms before and after the stimulus, and only correct responses were considered in the analysis. Time-frequency (1-50Hz) topographic maps were obtained for the increases and decreases of power after the event with respect to the pre-stimulus average values. Significant differences between groups were observed in the behavioral responses. LD-NOS children show less number of correct responses and more omissions and false alarms than the control group. The event-induced EEG responses showed significant differences between groups. The control group showed greater power increases in the frequencies 1-6Hz than the LD-NOS group from 300 to 700ms. These differences were mainly observed in frontal regions, both to related and non-related words. This was interpreted as a deficit in attention, both to internal and external events, deficits in activation of working memory and deficits in encoding and memory retrieval in the LD-NOS children. Differences between groups were also observed in the suppression of alpha and beta rhythms in the occipital regions to related words in frequencies between 8 and 17Hz from 450 to 750ms. LD-NOS children showed shorter durations of the decreases in power than the control group. These results suggest also deficits in attention and memory retrieval. It may be concluded that LD-NOS children showed physiological differences from normal children that may explain their cognitive deficiencies.     

Recognition,recollection, familiarity and executive function in medicated patients with moderate Parkinson's disease

There is conflicting evidence about whether Parkinson's disease (PD) is associated with deficiencies in recognition memory (RM) and the processes which underlie it, namely recollection (a form of recall) and familiarity (a feeling of memory in the absence of recall). The aims of the current study were to examine forced‐choice verbal RM (assessed with the Warrington Recognition memory Test), yes‐no RM, recollection, familiarity and executive functioning in 17 patients with moderate PD and 17 healthy volunteers matched for age and premorbid intelligence. We predicted that patients with moderate PD would display a significant recollection deficit on the yes‐no RM test, because their strategic memory processing that depends on executive functioning and is necessary for efficient encoding and/or retrieval, was disrupted. In contrast, familiarity memory, which is not dependent on these processes, and forced‐choice RM (which is largely dependent on familiarity) should show higher levels of preservation. We also predicted that recollection should be correlated with severity of executive dysfunction. Our findings revealed that the PD patients were as likely to accurately discriminate between targets and distractors as the healthy volunteers on both RM tests. However, the PD patients were significantly less reliant on recollection‐driven recognition decisions on the yes‐no RM test when compared with the healthy control group. The patients also displayed executive function deficits, but these were not correlated with recollection. The extent to which the PD patients' reliance on familiarity at the expense of recollection is explained by impairments in strategic memory processes/executive function and/or medial temporal lobe retrieval processes needs further exploration.     

Anarchic-hand syndrome: ERP reflections of lost control over the right hemisphere

In patients with the callosal type of anarchic-hand syndrome, the left hand often does not act as intended and counteracts the right hand. Reports are scarce about the underlying neurophysiological mechanisms. We report the case G.H. who developed the syndrome after infarction of the left arteria pericallosa. It has been suggested that the syndrome arises out of lacking inhibition from the dominant left hemisphere on the right hemisphere. Yet, in tests of spatial intelligence G.H. performed much better with his “anarchic” left hand than with his dominant right hand, similar to observations commonly reported in split-brain patients. Left-right manual choice responses and event-related EEG potentials to laterally presented stimuli were measured. Asymmetries were evident in G.H.’s behavior and EEG potentials, different from age-matched healthy participants (n = 11). His right-hand responses were fast and unaffected by incompatibility with stimulus location, whereas his left-hand responses were variable and accompanied by a large negative central-midline EEG potential, probably reflecting efforts in initiating the response. G.H.’s visual N1 component peaked earlier and was larger at the right than the left side of the scalp, and the P3 component was distinctly reduced at the right side. Both features occurred independent of side of stimulus presentation and side of responding hand. The effort indicated by the midline negativity and the asymmetrically reduced P3 might directly reflect G.H.’s lack of control on his right hemisphere’s processing. The faster visual processing of the right hemisphere suggested by the N1 asymmetry might contribute to “anarchic” processing, making the right hemisphere process stimuli before control impulses exert their effect. These neurophysiological results tend to support the split-brain account which assumes that the syndrome arises by the lack of communication between hemispheres that act according to their respective competences.     

Spatiotemporal variations of alpha and sigma band EEG in the waking-sleeping transition period

The aim of this study is to evaluate the spatiotemporal variation of alpha and sigma band EEGs during the waking-sleeping transition or hypnagogic period. Power and coherence from 7 EEG channels (Fp1, F7, Fz, C3, Pz, T5, O1) were studied using EEG records of the period of 5 min. before the onset of Stage 1 to 24 min. after the onset of Stage 1. The EEG spectra were computed for 4 frequency bands (alpha 1: 8.0-9.0 Hz, alpha 2: 9.5-11.0 Hz, alpha 3: 11.5-12.5 Hz, and sigma: 13.0-15.0 Hz). The power of alpha 1 and 2 bands initially started to decrease before the onset of Stage 1. Principal component analysis of the coherence yielded Generalized and Localized Components in each band. The Generalized Component was widespread across scalp areas, while the Localized Component was a restricted local area. The Generalized Components of alpha 1 and 2 bands reached stable levels of NREM sleep about 1 min. after the onset of Stage 1. The component of sigma band reached a stable level of NREM sleep about 0.6 min. before the onset of Stage 2, while the component of alpha 3 band reached a stable level of NREM sleep about 3.4 min. after the onset of Stage 2. These results suggest that the alpha-sigma band EEG structures during the waking-sleeping transition period may not be uniform across EEG bands and that the hypnagogic EEG changes may start before the onset of Stage 1 and continue for several minutes after the onset of Stage 2.