Baseline asymmetries in brain electrical activity predict dichotic listening performance.

Forty-four right-handed participants were assessed on 2 occasions 6 weeks apart on electrophysiological measures of activation asymmetry derived from spectral estimates of electroencephalogram (EEG) alpha power in homologous scalp electrodes. Approximately 4 months following the final EEG assessment. participants were administered a dichotic listening CV-syllables task. Overall, participants exhibited a highly significant right-ear advantage. Differences among individuals in ear asymmetry were predicted by the earlier recorded electrophysiological data. Participants with greater activation in left-sided posterior temporal and parietal regions showed a larger right-ear advantage. In addition, a larger right-ear advantage was predicted by right-sided prefrontal activation. These data indicate that some of the variance in dichotic listening performance can be explained by dispositional activation asymmetries and is associated with a complex pattern of posterior and anterior activation asymmetries. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

EEG hemispheric asymmetry during sexual arousal: Psychophysiological patterns in responsive, unresponsive, and dysfunctional men.

Investigated patterns of EEG hemispheric asymmetry and penile tumescence in 12 sexually functional and 6 dysfunctional men. All Ss were aged 31–60 yrs. Six sexually functional Ss were responsive and 6 were unresponsive to laboratory presentations of erotic stimuli. Each S was exposed to a counterbalanced sequence of visual and auditory conditions over 2 sessions of testing. Response measures included bilateral temporal and occipital EEG amplitude integrated over 5-sec epochs, strain gauge measures of penile tumescence, and subjective estimates of arousal. Analysis of the hemispheric laterality results indicated a pattern of right-temporal activation in association with maximum tumescence responses in the high-normal Ss. In contrast, the dysfunctional Ss showed moderate tumescence in response to the visual erotic stimuli but greater right-hemisphere activation in response to the auditory erotic stimuli. These psychophysiological patterns are consistent with the literature on cerebral asymmetry and affective arousal. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in anterior brain asymmetry and fundamental dimensions of emotion.

Assessed whether individual differences in anterior brain asymmetry are linked to differences in basic dimensions of emotion. In each of 2 experimental sessions, separated by 3 wks, resting EEG activity was recorded from female adults during 8 60-sec baselines. Mean alpha power asymmetry across both sessions was extracted in mid-frontal and anterior temporal sites. Across both regions, groups demonstrating stable and extreme relative left anterior activation reported increased generalized positive affect (PAF) and decreased generalized negative affect (NAF) compared with groups demonstrating stable and extreme relative right anterior activation. Additional correlational analyses revealed robust relations between anterior asymmetry and PAF and NAF, particularly among Ss who demonstrated stable patterns of EEG activation over time. Anterior asymmetry was unrelated to individual differences in generalized reactivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electroencephalogram asymmetry in response to the approach of a stranger and maternal separation in 10-month-old infants.

We recently reported the presence of reliable asymmetries in frontal-brain electrical activity in infants that distinguished between certain positive- and negative-affect elicitors. In order to explore the degree to which these asymmetries in brain activity are associated with individual differences in affective response, 35 ten-month-old female infants were presented with a stranger-approach, mother-approach, and maternal-separation experience while an electroencephalogram (EEG) from the left- and right-frontal and left- and right-parietal scalp regions was recorded and facial and other behavioral responses were videotaped. Changes in frontal-EEG asymmetry reflected behavioral changes between conditions. In addition, individual differences in affective response to separation were related to differences in frontal-brain asymmetries. These findings indicate that lawful changes exist in asymmetries of frontal-brain activation during the expression of certain emotions in the first year of life and that individual differences in emotional responsivity are related to these measures of brain activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Wada memory testing and hippocampal volume measurements in the evaluation for temporal lobectomy

We examined the relationship of Wada memory performance and MRI hippocampal volume measurements to laterality of ultimate seizure localization in 20 patients with complex partial seizures who later underwent temporal lobectomy. Discriminant function analysis employing both Wada memory test asymmetries and hippocampal volume asymmetries correctly classified 100% of the patients into left and right temporal lobe groups. Wada memory asymmetries alone correctly classified 90% of the sample (80% of the sample when the discriminant function included all patients except the one being classified), and hippocampal volume asymmetries alone correctly classified 90% of the patients. A significant correlation was present between Wada memory asymmetries and hippocampal volume asymmetries (r = 0.78), indicating that structural evidence of reduced hippocampal volume has a functional correlate reflected by Wada memory performance. These data suggest that the combination of functional and structural measures is of value in the preoperative evaluation for epilepsy surgery.     

Posttrial electrical stimulation of the dorsal hippocampus facilitates acquisition of the nictitating membrane response.

In 2 experiments, New Zealand albino rabbits with electrodes implanted in the dorsal hippocampus (DHC) were trained on the acquisition of the nictitating membrane response (NMR). Posttrial application of subseizure-level electrical stimulation within a single session resulted in facilitation of NMR conditioning. In contrast, seizure-level stimulation within a single session and subseizure-level stimulation in multiple sessions had no facilitatory or deleterious effects on NMR conditioning. It is suggested that DHC stimulation facilitates conditioning by activation of midbrain and cerebellar circuits. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A note on state individual differences in accuracy of response imagery: aftereffects and reminiscence

In two sessions, separated by 7 days, subjects imagined themselves performing a tracking task under a massed practice schedule. After conditions of interpolated rest and no-rest, which were counterbalanced across sessions, subjects actually performed the tracking task. During imagery practice, subjects verbally reported the temporal component of the task. The temporal accuracy of verbal reports varied widely across subjects, but not within subjects. Furthermore, a performance gain was demonstrated as a function of interpolated rest versus no-rest (reminiscence effect). Finally, the accuracy of verbal reports predicted imagery aftereffects, but not reminiscence effects.     

Patterns of brain electrical activity during facial signs of emotion in 10-month-old infants.

This study examined electroencephalogram (EEG) asymmetries during the presence of discrete facial signs of emotion. Thirty-five 10-month-old infants were tested in a standard stranger- and mother-approach paradigm that included a brief separation from their mother. Infant facial expression was videotaped, and brain electrical activity from left and right frontal and parietal regions was recorded. The videotapes were coded with two different discrete facial coding systems. Artifact-free periods of EEG were extracted that were coincident with the expression of the emotions of joy, anger, and sadness. The data revealed different patterns of EEG asymmetry depending on the type of facial expression and vocal expression of affect that was observed. Expressions of joy that involved facial actions of both zygomatic and orbicularis oculi were seen more often in response to mother approach, whereas smiles that did not involve the action of orbicularis oculi were seen more often in response to approach of the stranger. The former type of smile was associated with relative left frontal activation, whereas the latter type was associated with right frontal activation. Facial expressions of anger and sadness exhibited in the absence of crying were associated with left frontal activation, whereas these same facial expressions during crying were associated with right frontal activation. These data underscore the usefulness of EEG measures of hemispheric activation in differentiating among emotional states associated with differences in facial and vocalic expressivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognition and treatment of autonomic dysreflexia

We assessed functional relationships between hemispheres by calculating interhemispheric EEG coherence at rest and during photic stimulation in 18 never-medicated patients with paranoid schizophrenia and 30 control subjects. Although no significant group differences were found in the resting EEG, the schizophrenic patients had significantly higher coherence on EEGs recorded during photic stimulation, compared to the control subjects. In this study, we also examined the changes in interhemispheric coherence from rest to the stimulus condition (i.e., stimulation-related coherence reactivity); the patients were found to show significantly greater coherence reactivity to photic stimulation. These findings provide further evidence that schizophrenic patients have a higher degree of interhemispheric functional connectivity and thus have less lateralized cerebral organization than normal subjects. Our results also suggest that schizophrenic patients have excessive functional reorganization between hemispheres in association with photic stimulation.     

Rats use an ordinal timer in a daily time-place learning task.

Rats received 2 daily sessions in a large clear chamber. A lever was mounted on each of the 4 chamber walls. For each rat, a different level provided food during 0930 and 1530 sessions. The rats learned which lever would provide food at 0930 and 1530. Probe tests suggested that the rats learned to press 1 lever during their 1st session of each day and then to press a 2nd lever during their 2nd session of each day. We propose that this knowledge of the order of a set of events within a period of time constitutes ordinal timing. We contrast the temporal information provided by ordinal, phase, and interval timing and consider why multiple timing systems have evolved in animals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Baseline EEG asymmetries and performance on neuropsychological tasks

Thirty-two participants were tested for both resting electroencephalography (EEG) and neuropsychological function. Eight one-minute trials of resting EEG were recorded from 14 channels referenced to linked ears, which was rederived to an average reference. Neuropsychological tasks included Verbal Fluency, the Tower of London, and Corsi's Recurring Blocks. Asymmetries in EEG alpha activity were correlated with performance on these tasks. Similar patterns were obtained for delta and theta bands. Factor analyses of resting EEG asymmetries over particular regions suggested that asymmetries over anterior scalp regions may be partly independent from those over posterior scalp regions. These results support the notions that resting EEG asymmetries are specified by multiple mechanisms along the rostral/caudal plane, and that these asymmetries predict task performance in a manner consistent with lesion and neuroimaging studies.     

Extraordinary features in the Chlamydomonas reinhardtii chloroplast genome: (1). rps2 as part of a large open reading frame; (2). A C. reinhardtii specific repeat sequence

PURPOSE: To evaluate the clinical efficacy of local vaginal lidocaine application for pain relief during high-dose-rate (HDR) intracavitary brachytherapy for patients with cervical cancer, and to investigate sequential changes in serum levels of lidocaine during the procedures. METHODS AND MATERIALS: This prospective study was designed to examine the analgesic effect, physical response, and side effects of local anesthesia during HDR intracavitary brachytherapy. Forty patients were enrolled. All patients received 10-15 MV X-rays to the pelvis with a total dose of 45-59.4 Gy 5-6 weeks before undergoing HDR intracavitary brachytherapy. All patients underwent first intracavitary brachytherapy under general anesthesia. These patients were randomly allocated to receive one of two different treatment protocols as follows: (1) treatment session - control session - treatment session - control session; or (2) control session - treatment session- control session - treatment session. In the treatment sessions, topical anesthesia was administered using 4 ml of 10% lidocaine solution sprayed liberally on the cervix and vagina during intracavitary brachytherapy. In the control sessions, a placebo was administered in the same manner during brachytherapy. The Hensche's applicators for brachytherapy were inserted into the cervix and vagina 5 min after lidocaine application. The visual analogue scale (VAS) was used to assess pain and discomfort during brachytherapy. Blood pressure and heart rates were measured to evaluate the physiological response. Another prospective study was then performed to investigate the sequential changes of serum lidocaine levels during the anesthetic procedure. Eleven additional patients with similar disease state and demographic characteristics were enrolled and blood samples were obtained before, and 5, 15, 30, and 45 min after the initiation of lidocaine application. RESULTS: The mean VAS values recorded during the treatment sessions and control sessions were 49.9 +/- 24.1 versus 60.1 +/- 24.8, respectively. The value of VAS in the treatment session was significantly lower than that of the control session (p < 0.001). No statistically significant differences were found in the changes of blood pressure and heart rate and in the incidence of side effects during these two types of sessions (p > 0.05). In the drug-level study, serum levels of lidocaine reached a peak 5 min after the initiation of local anesthesia. The mean peak concentrations (Cmax) of lidocaine were 0.50 +/- 0.45 microg/ml. CONCLUSION: Local vaginal anesthesia with 10% lidocaine solution can significantly decrease the degree of painful sensation during HDR intracavitary brachytherapy, and is safe to administer for the procedure for cervical cancer.     

Single photon emission computed tomography (SPECT) in a patient with bilateral temporal seizures: correlation between ictal EEG and postictal/ictal SPECT

We report a patient with bilateral independent temporal lobe seizures in whom two [99mTc]HMPAO single photon emission computed tomograph (SPECT) scans were performed during two different seizures. In the first periictal SPECT, [99mTc]HMPAO was injected in the interval between two closely spaced seizures (one localized in the left temporal lobe and the other in the right temporal lobe). SPECT images showed hypoperfusion in the left lateral temporal lobe, hyperperfusion of the left mesial temporal region, and pronounced hyperperfusion in the right anterior temporal lobe. These results suggest both a postictal left temporal SPECT pattern and an ictal right temporal pattern. In the second periictal SPECT, [99mTc]HMPAO was injected immediately after a right temporal lobe seizure and showed right lateral temporal lobe hypoperfusion and right mesial hyperperfusion, suggesting a postictal right temporal SPECT pattern. Interpretation of the periictal SPECT should take into account EEG changes at the time or in the minutes immediately after injection of [99mTc]HMPAO.     

Cortisol secretion is related to electroencephalographic alertness in human subjects during daytime wakefulness

To determine whether human hypothalamo-pituitary-adrenal axis activity is related to the alertness level during wakefulness, 10 healthy young men were studied under resting conditions in the daytime (0900-1800 h) after an 8-h nighttime sleep (2300-0700 h). A serial 70-sec gaze fixation task was required every 10 min throughout the daytime experimental session. The corresponding waking electroencephalographic (EEG) segments were submitted to quantitative spectral analysis, from which EEG beta activity (absolute power density in the 13-35 Hz frequency band), an index of central alertness, was computed. Blood was collected continuously through an indwelling venous catheter and sampled at 10-min intervals. Plasma cortisol concentrations were measured by RIA, and the corresponding secretory rates were determined by a deconvolution procedure. Analysis of individual profiles demonstrated a declining tendency for EEG beta activity and cortisol secretory rate, with an overall temporal relationship indicated by positive and significant cross-correlation coefficients between the two variables in all subjects (average r=0.565, P < 0.001). Changes in cortisol secretion lagged behind fluctuations in EEG beta activity, with an average delay of 10 min for all the subjects. On the average, 4.6+/-0.4 cortisol secretory pulses and 4.9+/-0.5 peaks in EEG beta activity were identified by a detection algorithm. A significant, although not systematic, association between the episodes in the two variables was found: 44% of the peaks in EEG beta activity (relative amplitude, near 125%; P < 0.001) occurred during an ascending phase of cortisol secretion, cortisol secretory rates increasing by 40% (P < 0.01) 10-min after peaks in EEG beta activity. However, no significant change in EEG beta activity was observed during the period from 50 min before to 50 min after pulses in cortisol secretion. In conclusion, the present study describes a temporal coupling between cortisol release and central alertness, as reflected in the waking EEG beta activity. These findings suggest the existence of connections between the mechanisms involved in the control of hypothalamo-pituitary-adrenal activity and the activation processes of the brain, which undergoes varying degrees of alertness throughout daytime wakefulness.     

Electroencephalographic asymmetries in adolescents with major depression: Influence of comorbidity with anxiety disorders.

This study examined whether adolescents with major depressive disorder (MDD) display the abnormal electroencephalographic (EEG) alpha asymmetries found in depressed adults. Resting EEG was recorded in 25 right-handed female outpatients (19 with MDD, 11 of whom also had a current anxiety disorder; 6 with anxiety disorders only) and 10 non-ill controls. In contrast to the non-ill controls, adolescents having MDD but no anxiety disorder showed alpha asymmetry indicative of less activation over right than over left posterior sites. Within the MDD patient group, comorbid anxiety disorders reduced the posterior alpha asymmetry, supporting the potential importance of evaluating anxiety in studies of regional brain activation in adolescent MDD. These preliminary findings are similar to those from adult studies that suggest that MDD is associated with right parietotemporal hypoactivation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects on pubertal growth and reproduction in rats exposed to lead perinatally or continuously throughout development

The purpose of this study was to examine the effects of different exercise intensities with the anaerobic threshold (AT) as the standard on electroencephalograph (EEG) and heart rate variability (HRV). Eleven healthy males, with a mean age of 22 (SD 1.48) years, performed submaximal exercise to determine their ATs, and underwent four experimental conditions including rest (rest), 20% less than the AT level (-20), the AT level (AT), and 20% more than the AT level (+20) for about 20 minutes. EEG and electrocardiogram (ECG) were taken for 15 minutes before and after each experimental condition, respectively. The EEG signals were recorded from Cz, Pz, O1 and O2 (10-20 system). HRV was determined by the R-R interval method of ECG. Spectral analysis was applied to the EEG and the HRV from just before (pre) and after (post) each experimental condition for 5 minutes using the maximum entropy method (MEM). Post/pre ratios were calculated, after the power spectral density (PSD) and percentage of total power (power time percent: Time%) of delta (0.5-4 Hz), theta (4-8 Hz), alpha 1 (8-11 Hz), alpha 2 (11-14 Hz), beta 1 (14-20 Hz), beta 2 (20-30 Hz), total waves in EEG and PSD as to low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.4 Hz) areas, and the LF/HF(L/H) ratio in HRV were analyzed. In the exercise condition, total PSD in the EEG was enhanced and PSD of HF in HRV was significantly declined, as compared to those in the resting condition. Alpha PSDs of occipital sites were higher in -20 than those in AT and +20 conditions. The increase in L/H in AT and +20 demonstrated the changes in the balance of the autonomic nervous system, compared with that in -20. A significant increase in heart rate was observed in +20, although other indicators did not show differences in AT and +20 conditions. No alternations were noted in the gradient of exponential PSD in the above four experimental conditions, that is at rest, -20, AT and +20. These results suggest that the exercise intensity 20% less than one's AT level does not put a great strain on his or her body in health-promoting.     

Electroencephalographic laterality changes during human sexual orgasm

Left and right parietal EEGs were recorded while seven subjects experienced sexual climax through self-stimulation. EEG data were quantified by continuous cumulated measurements of the integrated areas of EEG recording during successive 1-sec epochs. In eight out of 12 experiments, this measure revealed a statistically significant change in laterality. Controlled replications with two of the original subjects obviated the possibility that two potential sources of artifact (hand used for masturbation and gross body movements) accounted for the changes. While previous research has focused on vasomotor and myotonic indices of sexual response, this study demonstrates the significance of brain phenomena in sexual orgasm.     

Instability of therapeutic conditions in psychotherapy.

Examined the stability of the therapeutic conditions of empathy, warmth, and genuineness of 3 high- and 3 low-functioning therapists with 1 ongoing patient per therapist. Repeated ratings of therapeutic facilitativeness in each recorded session reveal (a) that while high- and low-facilitative Ss generally tended to function at high and low levels, respectively, both groups were variable in their functioning across sessions and particularly within sessions with their patients; and (b) that therapeutic conditions tended to reach peak within-session levels in midlate and late segments of the therapy hour. Implications are discussed in terms of the dyadic interactive nature of therapeutic facilitativeness and methodological issues in sampling therapeutic functioning. (28 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

EEG activity and heart rate during recall of emotional events in hypnosis: relationships with hypnotizability and suggestibility

The purpose of the present research was to find physiological and cognitive correlates of hypnosis, imaginative suggestibility and emotional experiences. After the administration of a standard hypnotic induction, the EEG and heart rate (HR) were recorded during self-generated happy and sad emotions using a relaxation condition as a control. Physiological recordings were also obtained during three eyes-open and eyes-closed baseline periods: (1) waking rest; (2) early-rest in hypnosis (just after the hypnotic induction); (3) late-rest hypnosis (at the end of hypnotic condition). EEG was recorded at frontal (F3, F4), central (C3, C4), and posterior sites (middle of O1-P3-T5 and O2-P4-T6 triangles). Using log transform of mean spectral amplitude, eight EEG frequency bands (4-44 Hz) were evaluated. High hypnotizable subjects, as compared to the lows, produced a higher theta1 amplitude (4-6 Hz) across both left- and right-frontal and right-posterior areas. These subjects also produced smaller alpha1 amplitude (8.25-10 Hz) over both left and right frontal recording sites. High suggestible subjects, during resting conditions, disclosed higher theta2 (6.25-8 Hz) and alpha1 amplitudes in eyes-closed as compared to an eyes-open condition than did low suggestible subjects. High suggestible subjects also showed, in hypnosis-rest condition, higher 40-Hz amplitudes (36-44 Hz) and HR activity than did low suggestible subjects. Hypnotizability and not suggestibility was found to moderate emotional processing: high hypnotizable individuals self-reported greater levels of emotional experiences than did low hypnotizables especially in terms of negative emotion. High hypnotizables, during processing of emotional material, also disclosed opposite 40-Hz hemispheric asymmetries over anterior and posterior regions of the scalp. These subjects during happiness showed an increased production of 40-Hz activity in the left frontal and central regions of the scalp, while during sadness they showed an increased activity in the right central and posterior regions. The hemispheric asymmetries for relaxation condition were similar, but less marked, to those obtained for happiness. No significant interactions involving both hypnotizability and imaginative suggestibility were found for physiological variables considered in this study. This demonstrates that hypnotizability and suggestibility reflect different underlying psychophysiological activities.     

A hybrid computational model for ultrasound phased-array heating in presence of strongly scattering obstacles

BACKGROUND: Studies using electroencephalogram (EEG) measures of activation asymmetry have reported differences in anterior asymmetry between depressed and nondepressed subjects. Several studies have suggested reciprocal relations between measures of anterior and posterior activation asymmetries. We hypothesized that depressed subjects would fail to show the normal activation of posterior right hemisphere regions in response to an appropriate cognitive challenge. METHODS: EEG activity was recorded from 11 depressed and 19 nondepressed subjects during the performance of psychometrically matched verbal (word finding) and spatial (dot localization) tasks. Band power was extracted from all epochs of artifact-free data and averaged within each condition. Task performance was also assessed. RESULTS: Depressed subjects showed a specific deficit in the performance of the spatial task, whereas no group differences were evident on verbal performance. In posterior scalp regions, nondepressed controls had a pattern of relative left-sided activation during the verbal task and relative right-sided activation during the spatial task. In contrast, depressed subjects failed to show activation in posterior right hemisphere regions during spatial task performance. CONCLUSIONS: These findings suggest that deficits in right posterior functioning underlie the observed impairments in spatial functioning among depressed subjects.