Self-regulation of slow cortical potentials in psychiatric patients: depression.

Findings on depressive patients indicate that depressives have electrophysiological characteristics similar to those of schizophrenics, in that they exhibit reduced Contingent Negative Variation (CNV) amplitudes and more distinct Postimperative Negative Variations (PINVs) than normal controls. In a biofeedback experiment, 8 medicated male inpatients with the DSM III-R diagnosis of "Bipolar Disorder, Depressive," and "Major Depression" demonstrated no impairment in the self-regulation of Slow Cortical Potentials (SCP) in comparison to schizophrenics in terms of increasing and suppressing negativity. Continuous visual SCP feedback is presented to the patient as a horizontally moving rocket in a video game format. The direction changes of the rocket represented SCP changes at each point in time, recorded by the central EEG (based on the pretrial baseline). Depressives demonstrated SCP self-regulation across 20 sessions, although with many between-and-within variations. The 8 male controls were unable to regulate their SCPs across 5 sessions. This result contradicts other findings of our laboratory on normal controls. Motivational factors and insufficient operant reinforcement (financial reward) may have facilitated this effect.     

Self-regulation of slow cortical potentials in psychiatric patients: depression.

Findings on depressive patients indicate that depressives have electrophysiological characteristics similar to those of schizophrenics, in that they exhibit reduced Contingent Negative Variation (CNV) amplitudes and more distinct Postimperative Negative Variations (PINVs) than normal controls. In a biofeedback experiment, 8 medicated male inpatients with the DSM III-R diagnosis of "Bipolar Disorder, Depressive," and "Major Depression" demonstrated no impairment in the self-regulation of Slow Cortical Potentials (SCP) in comparison to schizophrenics in terms of increasing and suppressing negativity. Continuous visual SCP feedback is presented to the patient as a horizontally moving rocket in a video game format. The direction changes of the rocket represented SCP changes at each point in time, recorded by the central EEG (based on the pretrial baseline). Depressives demonstrated SCP self-regulation across 20 sessions, although with many between-and-within variations. The 8 male controls were unable to regulate their SCPs across 5 sessions. This result contradicts other findings of our laboratory on normal controls. Motivational factors and insufficient operant reinforcement (financial reward) may have facilitated this effect.     

Self-regulation of slow cortical potentials in psychiatric patients: Depression

Findings on depressive patients indicate that depressives have electrophysiological characteristics similar to those of schizophrenics, in that they exhibit reduced Contingent Negative Variation (CNV) amplitudes and more distinct Postimperative Negative Variations (PINVs) than normal controls. In a biofeedback experiment, 8 medicated male inpatients with the DSM III-R diagnosis of “Bipolar Disorder, Depressive,” and “Major Depression” demonstrated no impairment in the self-regulation of Slow Cortical Potentials (SCP) in comparison to schizophrenics in terms of increasing and suppressing negativity. Continuous visual SCP feedback is presented to the patient as a horizontally moving rocket in a video game format. The direction changes of the rocket represented SCP changes at each point in time, recorded by the central EEG (based on the pretrial baseline). Depressives demonstrated SCP self-regulation across 20 sessions, although with many between-and-within variations. The 8 male controls were unable to regulate their SCPs across 5 sessions. This result contradicts other findings of our laboratory on normal controls. Motivational factors and insufficient operant reinforcement (financial reward) may have facilitated this effect.     

Self-regulation of slow cortical potentials in psychiatric patients: Schizophrenia

Slow cortical potentials (SCPs) are considered to reflect the regulation of attention resources and cortical excitability in cortical neuronal networks. Impaired attentional functioning, as found in patients with schizophrenic disorders, may covary with impaired SCP regulation. This hypothesis was tested using a self-regulation paradigm. Twelve medicated male schizophrenic inpatients and 12 healthy male controls received continuous feedback of their SCPs, during intervals of 8 s each, by means of a visual stimulus (a stylized rocket) moving horizontally across a TV screen. The position of the feedback stimulus was a linear function of the integrated SCP at each point in time during the feedback interval. Subjects were required to increase or reduce negative SCPs (referred to pretrial baseline) depending on the presentation of a discriminative stimulus. The correct response was indicated by the amount of forward movement of the feedback stimulus and by monetary rewards. Schizophrenics participated in 20 sessions (each comprising 110 trials), while controls participated in 5 sessions. Compared with the healthy controls, schizophrenics showed no significant differentiation between negativity increase and negativity suppression during the first sessions. However, in the last 3 sessions, patients achieved differentiation similar to controls, demonstrating the acquisition of SCP control after extensive training.     

A New Method for Self-Regulation of Slow Cortical Potentials in a Timed Paradigm

A new method of slow cortical potential (SCP) biofeedback is described, in which subjects were presented with a sequence of two alternating tones. Subjects learned to adjust their SCPs with the 4-s rhythm of presented tones by producing directed SCP changes only in certain inter-tone intervals. Specifically, they learned to simultaneously produce two EEG signals: 1) positive or negative SCP shift at vertex, and 2) SCP asymmetry between the right and the left central area. After one training session, 13 healthy participants were able to differentiate significantly between the negativity and the positivity conditions; this differentiation was achieved within less than 300 ms after the discriminative signal, i.e. much faster than in previous studies employing traditional SCP biofeedback technique. However, these participants did not produce a significant hemispheric asymmetry in the first session. In the second experiment, five subjects participated in prolonged training (6 to 17 sessions). Highly significant control of SCP asymmetry over the precentral cortex was attained in four out of five participants. Advantages and disadvantages of the new method as compared with the classical SCP biofeedback technique are discussed.     

Self-regulation of slow cortical potentials in psychiatric patients: schizophrenia.

Slow cortical potentials (SCPs) are considered to reflect the regulation of attention resources and cortical excitability in cortical neuronal networks. Impaired attentional functioning, as found in patients with schizophrenic disorders, may covary with impaired SCP regulation. This hypothesis was tested using a self-regulation paradigm. Twelve medicated male schizophrenic inpatients and 12 healthy male controls received continuous feedback of their SCPs, during intervals of 8 s each, by means of a visual stimulus (a stylized rocket) moving horizontally across a TV screen. The position of the feedback stimulus was a linear function of the integrated SCP at each point in time during the feedback interval. Subjects were required to increase or reduce negative SCPs (referred to pretrial baseline) depending on the presentation of a discriminative stimulus. The correct response was indicated by the amount of forward movement of the feedback stimulus and by monetary rewards. Schizophrenics participated in 20 sessions (each comprising 110 trials), while controls participated in 5 sessions. Compared with the healthy controls, schizophrenics showed no significant differentiation between negativity increase and negativity suppression during the first sessions. However, in the last 3 sessions, patients achieved differentiation similar to controls, demonstrating the acquisition of SCP control after extensive training.     

Deactivation of Brain Areas During Self-Regulation of Slow Cortical Potentials in Seizure Patients

This study investigates the neurophysiological basis of EEG feedback for patients with epilepsy. Brain areas are identified that become hemodynamically deactivated when epilepsy patients, trained in EEG self-regulation, generate positive slow cortical potentials (SCPs). Five patients were trained in producing positive SCPs, using a training protocol previously established to reduce seizure frequency in patients with drug refractory epilepsy. Patients attempted to produce positive SCP shifts in a functional magnetic resonance imaging (fMRI) scanner. Two patients were able to reliably produce positive SCP shifts. When these successful regulators were prompted to produce positive SCPs, blood oxygen level-dependent (BOLD) response indicated deactivation, in comparison to a control state, around the recording electrode, frontal lobe, and thalamus. Unsuccessful regulators’ BOLD response indicated no deactivation in cortical areas proximal to the active electrode. No thalamic deactivation was found in poor regulators. Decreased seizure frequency from SCP training may be the result of positively reinforced inhibition in cortical areas proximal to active electrode placement, the frontal cortex, and the thalamus.     

Simultaneous fMRI and EEG during the Multi-Source Interference Task

Background

fMRI and EEG are two non-invasive functional imaging techniques within cognitive neuroscience that have complementary advantages to obtain both temporal and spatial information. The multi-source interference task (MSIT) has been shown to generate robust activations of the dorsal anterior cingulate cortex (dACC) on both a single-subject level and in group averages, in fMRI studies. We have now simultaneously acquired fMRI and EEG during a cognitive interference task.

Materials and Methods

Healthy volunteers were tested in an MRI scanner with simultaneous EEG and fMRI recordings during the MSIT.

Results

The interference condition significantly increased the reaction time in the task. The fMRI analyses revealed activation of dACC as expected, in all subjects at the individual level and in group analyses. The posterior cingulate cortex was de-activated. Simultaneous EEG showed the expected anterior distribution of the interference effect, as it was restricted to frontal sites within a time frame of 80–120 ms post response.

Conclusion

The MSIT task is a reliable task for interference evaluation. fMRI shows robust activation of dACC and by adding EEG, an interference effect can be noticed within a temporal interval of 80–120 ms after the response, as a CRN (correct response negativity). This means that EEG could add a more detailed temporal aspect to the fMRI data from an interference task, and that despite the hostile environment within an MRI scanner, EEG data could be used.     

Changes in EEG Power Spectra During Biofeedback of Slow Cortical Potentials in Epilepsy

The goal of the study was to explore parallel changes in EEG spectral frequencies during biofeedback of slow cortical potentials (SCPs) in epilepsy patients. Thirty-four patients with intractable focal epilepsy participated in 35 sessions of SCP self-regulation training. The spectral analysis was carried out for the EEG recorded at the same electrode site (Cz) that was used for SCP feedback. The most prominent effect was the increase in the 2 power (6.0–7.9 Hz) and the relative power decrement in all other frequency bands (particularly 1, 2, and 2) in transfer trials (i.e., where patients controlled their SCPs without continuous feedback) compared with feedback trials. In the second half of the training course (i.e., sessions 21–35) larger power values in the , , and bands were found when patients were required to produce positive versus negative SCP shifts. Both across-subject and across-session (within-subject) correlations between spectral EEG parameters, on the one hand, and SCP data, on the other hand, were low and inconsistent, contrary to high and stable correlations between different spectral variables. This fact, as well as the lack of considerable task-dependent effects during the first part of training, indicates that learned SCP shifts did not directly lead to the specific dynamics of the EEG power spectra. Rather, these dynamics were related to nonspecific changes in patients' brain state.     

Gut SCP is an immune-relevant molecule involved in the primary immunological memory or pattern recognition in the amphioxus Branchiostoma belcheri

To understand the role of calcium-binding proteins of invertebrates in immunological response, amphioxus sarcoplasmic calcium-binding protein (SCP) was investigated in the present study. Following gene cloning, recombinant protein expression and purification and antibody preparation, the expression and alteration of SCP in the response to bacterial challenge were detected using Western blotting. SCP was not detected in the branchia, humoral fluid, gonad or in the gut of wounded animals, but it was abundant in muscle and appeared in the gut of healthy animals using Vibrio parahaemolyticus immunization and challenge. Furthermore, whether gut SCP possessed anamnestic response was investigated using cross-immune challenge between Gram-positive and -negative bacteria. Gut SCP showed stronger anamnestic activity or pattern-recognition in response to Gram-negative bacterium V. parahaemolyticus than Gram-positive bacterium Staphylococcus aureus. The response was faster and more species-specific to V. parahaemolyticus, whereas it was slower and longer to S. aureus. The reason why the response showed significant difference between Gram-positive and -negative bacteria awaits investigation. These results indicate that gut SCP is an immune-relevant molecule involved in the primary immunological memory or pattern recognition in the amphioxus Branchiostoma belcheri.     

Impaired passive avoidance acquisition in Wistar rats after restraint/cold stress and/or stresscopin administration

Stresscopin (SCP) and related peptides are new members of the corticotropin-releasing factor (CRF) peptide family that are selective ligands for CRF type 2 receptor; these ligands are essential for maintaining homeostasis after stress. SCP (i.p. injections) was tested on the passive avoidance learning task in stressed Wistar rats; it impaired the formation of memory trace. The retention performance deficit induced by SCP was comparable with the deficit induced by the stressor of restraint/cold. More profound impairment of avoidance response occurred following combined application of SCP and stressor. More specific actions of SCP can be expected from its studies with targeted intracerebral applications.     

Self-regulation of slow cortical potentials in psychiatric patients: Alcohol dependency

Ten unmedicated alcohol-dependent male inpatients participated in a Slow Cortical Potential (SCP) self-regulation task utilizing biofeedback and instrumental conditioning. These patients were hospitalized for treatment of alcohol dependency after chronic abuse of alcoholic beverages. Somatic withdrawal symptomatology had occurred recently and the patients were free of any withdrawal symptoms of the autonomic nervous system. Immediately after hospitalization patients were unable to control their SCPs without the reinforcement of immediate feedback across 4 sessions. Seven patients participated in a fifth session an average of 4 months later. Six out of these 7 patients had not had a relapse at the follow-up. In the fifth session these patients were immediately able to differentiate between the required negativity and negativity suppression, whereas the seventh patient, who had relapsed, was unable to control his brain potentials successfully. Results are further evidence that some of the frontocortical dysfunctions in alcohol-dependent patients are reversible. This could covary with a morphological restitution of the cortex.     

Changes of slow and steady brain potentials during complex tasks

Recordings of slow potentials and changes of steady level of the EEG in man during manual and mental tasks show that an increase in mental load (as determined by the difficulty of the task) is accompanied by an increase in negativity at midline electrodes. It is suggested that this negativity is due to cortical excitation that facilitates performance.     

The Relation Between Trait Anger and Impulse Control in Forensic Psychiatric Patients: An EEG Study

Inhibitory control is considered to be one of the key factors in explaining individual differences in trait anger and reactive aggression. Yet, only a few studies have assessed electroencephalographic (EEG) activity with respect to response inhibition in high trait anger individuals. The main goal of this study was therefore to investigate whether individual differences in trait anger in forensic psychiatric patients are associated with individual differences in anger-primed inhibitory control using behavioral and electrophysiological measures of response inhibition. Thirty-eight forensic psychiatric patients who had a medium to high risk of recidivism of violent and/or non-violent behaviors performed an affective Go/NoGo task while EEG was recorded. On the behavioral level, we found higher scores on trait anger to be accompanied by lower accuracy on NoGo trials, especially when anger was primed. With respect to the physiological data we found, as expected, a significant inverse relation between trait anger and the error related negativity amplitudes. Contrary to expectation, trait anger was not related to the stimulus-locked event related potentials (i.e., N2/P3). The results of this study support the notion that in a forensic population trait anger is inversely related to impulse control, particularly in hostile contexts. Moreover, our data suggest that higher scores on trait anger are associated with deficits in automatic error-processing which may contribute the continuation of impulsive angry behaviors despite their negative consequences.     

Effects of modulation of GABA-and noradrenergic transmission on impulse activity of neurons of the cat motor cortex related to realization of an operant reflex to the action of two signals

On unanesthetized cats trained to perform placing movements to the action of two subsequent signals (warning and imperative stimuli), we examined reflex-related impulse activity (IA) of neurons of the motor cortex (field 4) and simultaneous changes in the “slow” cortical potentials (SCP) in the vertex zone. In almost all cases under study, the shift in the SCP toward negativity was associated with a decrease in the frequency of IA within interstimulus intervals; this corresponded to a period of focusing of the animal’s attention on the expected imperative stimulus. Using a microiontophoretic technique, we tried to elucidate the role of GABA-and adrenergic cerebral systems in the genesis of such inhibitory periods. We conclude that, independently of each other but synchronously, both these systems can be involved in the maintenance of processes of active inhibition in the cerebral cortex under conditions of realization of an operant reflex. Neirofiziologiya/Neurophysiology, Vol. 39, No. 1, pp. 62–68, January–February, 2007.     

Hormonal triggering of the diurnal variation of sterol carrier protein

Rat liver sterol carrier protein (SCP) is a major intracellular protein regulating lipid metabolism and transport. During a dark-light cycle, SCP undergoes a dramatic diurnal variation in synthesis and level, reflecting translational events. Several hormones participate in the control of SCP synthesis. Insulin was implicated when the circadian rhythm of SCP was lost in both diabetes and fasting, states where insulin is low. After a 12-h fast the amplitude of the diurnal rhythm is diminished; after a 48-h fast it disappears, although SCP synthesis and level remain high. When endogenous insulin secretion is increased in fasted rats by glucose administration, SCP increases 2-fold in less than 30 min. When food intake is manipulated, but the dark-light cycle is unchanged, the circadian rhythm of SCP corresponds to feeding patterns and not light cycling. During feeding, increases in SCP are triggered following the expected increase in serum insulin. However, SCP is rapidly and significantly elevated in response to insulin only when glucocorticoids are normally high or increased by injection of the synthetic glucocorticoid, dexamethasone. Hepatocyte SCP levels are also induced by a combination of insulin and dexamethasone (2.3-fold) or insulin alone (1.3-fold). Dexamethasone alone causes a striking depression of SCP (2.4-fold). Thus, insulin is a major regulator of the diurnal variation of SCP synthesis. Glucocorticoids and other hormones (e.g. triiodothyronine) are also essential for maximum induction of SCP but play permissive roles.     

Variability in Host Preference Among Field Populations of Heterodera glycines

Eighteen soybean fields, six each with race 3, race 4, or Bedford population of Heterodera glycines, were selected for testing of host variability. Each field was divided into three sections, and a bulk soil sample was taken from each section. The 54 bulk soil populations (BSP) and 270 single cyst populations (SCP) were subjected to race determination tests. Tests of the 18 BSP and 90 SCP from the race 3 fields revealed that race 3 was the predominant race; however, 68 of the populations tested were other races. Tests of the 18-BSP and 90 SCP from race 4 fields demonstrated that races 2 and 4 were predominant, with 38 and 39 populations; respectively. Tests of the 18 BSP and 90 SCP from the Bedford population fields revealed tremendous variability. Races 2, 4, and 6 were the predominant races, with 32, 31, and 28 populations, respectively. These results indicate that of the three races studied, the Bedford population is the most variable, race 3 shows considerable variability, and race 4 shows very little.     

Molecular characterization of the sarcoplasmic calcium-binding protein (SCP) from crayfish Procambarus clarkii

Sarcoplasmic Calcium-binding Protein (SCP) is believed to function as the invertebrate equivalent of vertebrate parvalbumin, namely to “buffer” cytosolic Ca²⁺. We have cloned and characterized a novel SCP from axial abdominal muscle of crayfish Procambarus clarkii (referred to as pcSCP1), and have examined tissue specific distribution and expression as a function of molting stage in non-epithelial and epithelial tissues. The complete sequence of pcSCP1 consists of 1052 bp with a 579 bp open reading frame, coding for 193 amino acid residues (molecular mass of 21.8 kDa). There is a 387 bp 3′ terminal non-coding region with a poly (A) tail. The deduced pcSCP1 protein sequence matched most closely with published SCP sequences from another crayfish Astacus leptodactylus (92.8%) and from shrimp (78.6–81.2%) and fruit fly (53%). Real-time PCR analysis confirmed that pcSCP1 is ubiquitously expressed in all tissues tested (gill, hepatopancreas, intestine, antennal gland, muscle); however it is most abundant in muscle particularly in the axial abdominal muscle. The real-time PCR analysis revealed that pcSCP1 expression is downregulated in pre- and postmolt stages compared with intermolt. Epithelial (hepatopancreas and antennal gland) SCP expression exhibited a more dramatic decrease than that observed in muscle. Expression trends for pcSCP1 paralleled published trends for sarco/endoplasmic reticular calcium ATPase (SERCA), suggesting that their cellular function in regulating intracellular Ca²⁺ is linked.     

Relationship between supercooling point and mortality at low temperatures in Indianmeal moth (Lepidoptera: Pyralidae)

Indianmeal moth, Plodia interpunctella (Hübner), is classified as a freeze-intolerant organism and one of the most cold-tolerant stored-product pests. The objective of this study was to determine the relationship between mortality at low temperatures after minimum exposure and the supercooling point (SCP) for laboratory-reared P. interpunctella at different stages of development. This relationship also was analyzed for field-collected, cold-acclimated fifth instars. Mean SCP of laboratory-reared larvae (i.e., feeding stage) was consistently above approximately -16 degrees C. Mean SCP of laboratory-reared pupae and adults (i.e., nonfeeding stages) and field-collected, cold-acclimated fifth instars was consistently below approximately -21 degrees CP seemed to be the boundary between survival and death for larvae. However, it seemed that a 1-min exposure was not sufficient to cause larval mortality at the SCP. Alternatively, for both pupae and adults, the SCP seemed not to play an important role in their survival at low temperatures, with significant mortality observed at temperatures higher than the mean SCP. Adults were the most susceptible to low temperatures with no survival occurring at -20 degrees C, > 3 degrees C above its mean SCP. Results of this investigation demonstrate that P. interpunctella has a different response to low temperatures depending on stage of development and cold acclimation. Classifying P. interpunctella only as a freeze-intolerant organism disregards the occurrence of prefreeze mortality in this species. Therefore, a reclassification of this species (e.g., chill tolerant or chill susceptible) based on the extent of prefreeze mortality and the temperature and time of exposure at which it occurs is suggested.     

The role of sterol carrier protein 2 in stimulation of steroidogenesis in rat adrenal mitochondria by adrenal cytosol

Cholesterol side-chain cleavage (CSCC) in isolated rat adrenal mitochondria is enhanced by prior corticotropin (ACTH) stimulation in vivo (8-fold). Part of this stimulation is retained in vitro by addition of cytosol from ACTH-stimulated adrenals to mitochondria from unstimulated rats (2.5- to 6-fold). In vivo cycloheximide (CX) treatment fully inhibits the in vivo response and resolves the in vitro cytosolic stimulation into components: (i) ACTH-sensitive, CX-sensitive; (ii) ACTH-sensitive, CX-insensitive; and (iii) ACTH-insensitive, CX-insensitive. These components contribute approximately equally to stimulation by ACTH cytosol. Components (i) and (iii) most probably correspond to previously identified cytosolic constituents steroidogenesis activator peptide and sterol carrier protein 2 (SCP2). SCP2, as assayed by radioimmunoassay or ability to stimulate 7-dehydrocholesterol reductase, was not elevated in adrenal cytosol or other subcellular fractions by ACTH treatment. Complete removal of SCP2 from cytosol by treatment with anti-SCP2 IgG decreased cytosolic stimulatory activity by an increment that was independent of ACTH or CX treatment. Addition of an amount of SCP2, equivalent to that present in cytosol, restored activity to SCP2-depleted cytosol but had no effect alone or when added with intact cytosol, suggesting the presence of a factor in cytosol that potentiates SCP2 action. Pure hepatic SCP2 stimulated CX mitochondrial CSCC 1.5- to 2-fold (EC50 0.7 microM) but was five times less potent than SCP2 in adrenal cytosol. Two pools of reactive cholesterol were distinguished in these preparations characterized, respectively, by succinate-supported activity and by additional isocitrate-supported activity. ACTH cytosol and SCP2 each stimulated cholesterol availability to a fraction of mitochondrial P450scc that was reduced by succinate but failed to stimulate availability to additional P450scc reduced only by isocitrate.