Relationship of cerebral oxygen uptake to EEG frequency in isolated canine brain

Cerebral oxygen uptake was correlated with electroencephalographic (EEG) frequency and amplitude in 87 isolated canine brains. Group I (71 brains) was perfused with diluted blood and Group II (16 brains) was perfused with whole blood equilibrated with oxygen at various partial pressures. The EEG's were classified as follows: A, highest frequency greater than or equal to 17 Hz, alpha (8-13 Hz) amplitude less than 50 muv, delta (less than or equal to 3.5 Hz), amplitude less than 100 muv; B, highest frequency greater than or equal to 17 Hz, alpha amplitude greater to or equal to 50 muv, and/or delta amplitude greater than or equal to 100 muv. C, highest frequency 8-16 Hz, alpha amplitude greater than or equal to 25 muv, and delta amplitude greater than 100 muv, D, highest frequency 0.5-16 Hz, alpha, if present, amplitude less than 25 muv, and/or delta amplitude less than 100 muv, and E, highest frequency 0-16 Hz, alpha, if present, amplitude less than 10 muv, and/or delta amplitude less than 15 muv. The Group I oxygen uptakes in ml/100 g of brain per min+/-SE for the five EEG classifications were A, 4.39+/-0.06, B, 4.13+/-0.08, C, 3.76+/-0.09, D, 3.40+/-0.12, and E, 2.55+/-0.06, whereas the corresponding Group II values were A, 4.64+/-0.22, B, 4.28+/-0.15, C, 3.82+/-0.24, D, 3.39+/-0.40, and E, 1.38+/-0.42. As the EEG deteriorates, cerebral oxygen uptake tends to decrease in a significant and parallel manner in both the diluted and whole blood groups.     

Episodic multiregional cortical coherence at multiple frequencies during visual task performance

The way in which the brain integrates fragmentary neural events at multiple locations to produce unified perceptual experience and behaviour is called the binding problem. Binding has been proposed to involve correlated activity at different cortical sites during perceptuomotor behaviour, particularly by synchronization of narrow-band oscillations in the gamma-frequency range (30-80 Hz). In the rabbit olfactory system, inhalation induces increased gamma-correlation between sites in olfactory bulb and cortex. In the cat visual system, coherent visual stimuli increase gamma-correlation between sites in both the same and different visual cortical areas. In monkeys, some groups have found that gamma-oscillations transiently synchronize within striate cortex, superior temporal sulcus and somatosensorimotor cortex. Others have reported that visual stimuli produce increased broad-band power, but not gamma-oscillations, in several visual cortical areas. But the absence of narrow-band oscillations in itself does not disprove interregional synchronization, which may be a broad-band phenomenon. We now describe episodes of increased broad-band coherence among local field potentials from sensory, motor and higher-order cortical sites of macaque monkeys performing a visual discrimination task. Widely distributed sites become coherent without involving other intervening sites. Spatially selective multiregional cortical binding, in the form of broad-band synchronization, may thus play a role in primate perceptuomotor behaviour.     

Relationship between memory and metamemory performance: A comparison of specific and general strategy knowledge.

Examines (1) age and skill-level differences in metamemory and memory performance; (2) differences in memory and metamemory as a function of type of task and instructional support; (3) whether task-specific metamemory predicts performance better than general metamemory; and (4) whether previous metamemory findings generalize to a variety of memory tasks. 62 average and 66 low-achieving children participated in 3 sessions. General metamemory was assessed for hypothetical performance, with task-specific metamemory assessed for actual performance. Memory performance was assessed across a variety of tasks. Memory improved with age and skill level. Age and skill-level differences were not consistent across metamemory tasks. Strategic metamemory revealed age and skill-level differences, whereas taxonomic metamemory revealed age differences in the average group only. Educational and theoretical relevance of the results are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypothyroidism alters the expression of prostaglandin D2 synthase/beta trace in specific areas of the developing rat brain

Lipocalin-type prostaglandin D2 synthase is the enzyme responsible for the synthesis of prostaglandin D2, a major prostaglandin in the central nervous system. We analysed the effects of thyroid hormone deprivation on prostaglandin D2 synthase gene expression in the developing rat brain. By in situ hybridization, the strongest prostaglandin D2 synthase mRNA signal was detected in the leptomeninges and choroid plexus. The signal was greatly reduced in the cerebellar interlaminar meninges of hypothyroid rats aged 15 and 25 days. Immunohistochemical studies defined changes in the location of the prostaglandin D2 synthase protein. In control but not in hypothyroid animals, Cajal-Retzius neurons of cortical layer I, and pyramidal cortical plate neurons were intensely stained on postnatal day 5. Conversely, prostaglandin D2 synthase protein levels were higher in neurons of the CA1 and CA3 regions and the dentate gyrus of the hippocampus of hypothyroid animals on postnatal days 5, 15 and 25, and also in subplate neurons on postnatal days 15 and 25. In agreement with the in situ hybridization and northern blotting data, the major difference was found in the cerebellar interlaminar meninges of hypothyroid animals, where the protein was clearly down-regulated on postnatal days 15 and 25. These results show that hypothyroidism causes both age- and region-specific alterations in the expression and location of the prostaglandin D2 synthase during postnatal brain development, probably reflecting a cell-specific regulatory effect of thyroid hormone on the prostaglandin D2 synthase.     

Dielectric properties of human blood at microwave frequencies

Waveguides systems have been used to obtain measurements for the complex permittivity of human blood in the frequent range 29-90 GHz. The data are reported and analysed in conjunction with lower frequency work, in particular that of Wei. There are two distinct regimes of behaviour in the spectra obtained: a high-frequency relaxation process in parallel with a lower frequency fractional power-law response.     

WISC performance in acting-out and delinquent children with and without EEG abnormality.

To evaluate the relationship between EEG status and intelligence test performance, the WISC scores of 139 nondefective, acting-out and delinquent children referred for psychiatric evaluation were examined. The distribution of Verbal IQ-Performance IQ (VIQ-PIQ) discrepancies was compared with that reported for the WISC standardization population. Girls did not differ significantly from the standardization population, but boys showed a significantly larger proportion with PIQ > VIQ than in the standardization population. Neither boys nor girls showed significant differences in scores between groups with abnormal EEGs and those with normal and borderline EEGs. (18 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Magnetic properties of non-oriented magnetic steel at medium frequencies

The magnetic properties of non-oriented magnetic steel are specified at a frequency of 50 or 60 Hz. The effect of increasing the frequency of the magnetizing field upon the specific total loss, the field strength and the specific apparent power is demonstrated. Regarding the non-oriented steel at 50 Hz total loss comprises mainly hysteresis loss, whereas the eddy-current loss of most of the grades amounts to less than 40%. The approximately square increase of the eddy-current loss with frequency means that at 400 Hz the total loss is determined by the resistivity. For excitations up to a peak polarization of 1.6 T increasing sheet thickness results in an increasing field strength at 400 Hz. While at 50 Hz low-alloyed grades have a lower field strength above 1.3 T, at 400 Hz the field strength of the high-alloyed grades is more favourable up to 1.4 T. With respect to the apparent power, the square of which is proportional to the copper losses, there is an advantage of the higher alloyed grades up to 1.5 T.     

Relationship of coaching with performance in situational employment interviews.

This field study addressed the question of whether voluntary participation in interview coaching is related to performance in situational interviews. Promotional procedures in 4 different police and fire department jobs were involved, allowing replication in separate samples. In 3 of 4 jobs, when controlling for indicators of candidates' precoaching job knowledge and motivation to do well on the promotional procedures, attendance at a coaching session was significantly related to interview performance. Following a discussion of study limitations, an agenda for future research is discussed, including a proposed general model of coaching process and outcome variables. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Determination of the dielectric characteristics of powders at superhigh frequencies

Conclusions The measurement method described enables the dielectric characteristics of powder objects in the shf range to be determined with errors of not more than ±2% in and not more than ±15% in tan. Conversion of results of measurements on the dielectric parameters in wide ranges of particle sizes and values of can best be performed with formula (9). To obtain silicon nitride materials characterized by a low level of dielectric losses, it is necessary to reduce to a minimum their impurity content and ensure that their composition approximates as closely as possible to stoichiometric.Translated from Poroshkovaya Metallurgiya, No. 3(207), pp. 65–72, March, 1980.     

Assessment of digital EEG, quantitative EEG, and EEG brain mapping: report of the American Academy of Neurology and the American Clinical Neurophysiology Society

A. Digital EEG is an established substitute for recording, reviewing, and storing a paper EEG record. It is a clear technical advance over previous paper methods. It is highly recommended. (Class III evidence, Type C recommendation). B. EEG brain mapping and other advanced QEEG techniques should be used only by physicians highly skilled in clinical EEG, and only as an adjunct to and in conjunction with traditional EEG interpretation. These tests may be clinically useful only for patients who have been well selected on the basis of their clinical presentation. C. Certain quantitative EEG techniques are considered established as an addition to digital EEG in: C.1. Epilepsy: For screening for possible epileptic spikes or seizures in long-term EEG monitoring or ambulatory recording to facilitate subsequent expert visual EEG interpretation. (Class I and II evidence, Type A recommendation as a practice guideline). C.2. OR and ICU monitoring: For continuous EEG monitoring by frequency-trending to detect early, acute intracranial complications in the OR or ICU, and for screening for possible epileptic seizures in high-risk ICU patients. (Class II evidence, Type B recommendation as a practice option). D. Certain quantitative EEG techniques are considered possibly useful practice options as an addition to digital EEG in: D.1. Epilepsy: For topographic voltage and dipole analysis in presurgical evaluations. (Class II evidence, Type B recommendation). D.2. Cerebrovascular Disease: Based on Class II and III evidence, QEEG in expert hands may possibly be useful in evaluating certain patients with symptoms of cerebrovascular disease whose neuroimaging and routine EEG studies are not conclusive. (Type B recommendation). D.3. Dementia: Routine EEG has long been an established test used in evaluations of dementia and encephalopathy when the diagnosis remains unresolved after initial clinical evaluation. In occasional clinical evaluations, QEEG frequency analysis may be a useful adjunct to interpretation of the routine EEG when used in expert hands. (Class II and III evidence as a possibly useful test, Type B recommendation). E. On the basis of current clinical literature, opinions of most experts, and proposed rationales for their use, QEEG remains investigational for clinical use in postconcussion syndrome, mild or moderate head injury, learning disability, attention disorders, schizophrenia, depression, alcoholism, and drug abuse. (Class II and III evidence, Type D recommendation). F. On the basis of clinical and scientific evidence, opinions of most experts, and the technical and methodologic shortcomings, QEEG is not recommended for use in civil or criminal judicial proceedings. (Strong Class III evidence, Type E recommendation). G. Because of the very substantial risk of erroneous interpretations, it is unacceptable for any EEG brain mapping or other QEEG techniques to be used clinically by those who are not physicians highly skilled in clinical EEG interpretation. (Strong Class III evidence, Type E recommendation).     

The junction-associated protein AF-6 interacts and clusters with specific Eph receptor tyrosine kinases at specialized sites of cell-cell contact in the brain

The AF-6/afadin protein, which contains a single PDZ domain, forms a peripheral component of cell membranes at specialized sites of cell-cell junctions. To identify potential receptor-binding targets of AF-6 we screened the PDZ domain of AF-6 against a range of COOH-terminal peptides selected from receptors having potential PDZ domain-binding termini. The PDZ domain of AF-6 interacts with a subset of members of the Eph subfamily of RTKs via its COOH terminus both in vitro and in vivo. Cotransfection of a green fluorescent protein-tagged AF-6 fusion protein with full-length Eph receptors into heterologous cells induces a clustering of the Eph receptors and AF-6 at sites of cell-cell contact. Immunohistochemical analysis in the adult rat brain reveals coclustering of AF-6 with Eph receptors at postsynaptic membrane sites of excitatory synapses in the hippocampus. Furthermore, AF-6 is a substrate for a subgroup of Eph receptors and phosphorylation of AF-6 is dependent on a functional kinase domain of the receptor. The physical interaction of endogenous AF-6 with Eph receptors is demonstrated by coimmunoprecipitation from whole rat brain lysates. AF-6 is a candidate for mediating the clustering of Eph receptors at postsynaptic specializations in the adult rat brain.     

Relationship between interpersonal psychotherapy problem areas with temperament and character: a pilot study

Hematogenous leukocytes infiltrate the CNS after inflammatory stimuli, including infection, mechanical trauma and excitotoxic neuronal necrosis. However,the role of leukocytic inflammation in promoting or hindering tissue repair is poorly understood. Identification of signals that lead to leukocyte recruitment and activation is essential for the designing of interventions that modulate inflammation, thus improving neurological outcome. Chemokines are small pleiotropic chemoattractant cytokines whose target specificity suggests an important role in determining the cellular composition of inflammatory infiltrates. Chemokine expression profiles in the CNS during autoimmune and post-traumatic inflammation correlate well with the composition of leukocyte infiltrates, and expression studies in systems such as transgenic mice, suggest that chemokines have potent functional attributes in CNS physiology. We propose that selective chemokine expression by CNS cells is crucial for post-traumatic leukocyte accumulation.     

Relationship of genetically transmitted alpha EEG traits to anxiety disorders and alcoholism

We tested the hypothesis that a heritable EEG trait, the low voltage alpha (LV), is associated with psychiatric disorders. Modest to moderate evidence for genetic linkage of both panic disorder and the low voltage alpha trait to the same region of chromosome 20q has recently been reported, raising the issue of whether there is a phenotypic correlation between these traits. A total of 124 subjects including 50 unrelated index subjects and 74 relatives were studied. Alpha EEG power was measured and EEG phenotypes were impressionistically classified. Subjects were psychiatrically interviewed using the SADS-L and blind-rated by RDC criteria. Alcoholics were four times more likely to be LV (including so-called borderline low voltage alpha) than were nonalcoholic, nonanxious subjects. Alcoholics with anxiety disorder are 10 times more likely to be LV. However, alcoholics without anxiety disorder were similar to nonalcoholics in alpha power. An anxiety disorder (panic disorder, phobia, or generalized anxiety) was found in 14/17 LV subjects as compared to 34/101 of the rest of the sample (P < 0.01). Support for these observations was found in the unrelated index subjects in whom no traits would be shared by familial clustering. Lower alpha power in anxiety disorders was not state-dependent, as indicated by the Spielberger Anxiety Scale. Familial covariance of alpha power was 0.25 (P < 0.01). These findings indicate there may be a shared factor underlying the transmissible low voltage alpha EEG variant and vulnerability to anxiety disorders with associated alcoholism. This factor is apparently not rare, because LV was found in approximately 10% of unrelated index subjects and 5% of subjects free of alcoholism and anxiety disorders.     

Learning performance varies with brain weight in heterogeneous mouse lines.

Three lines of unselected heterogeneous stocks of mice—Fuller HET, Roderick SEL 19B, and Roderick SEL 16C—were tested for learning and activity in active avoidance acquisition and extinction, water-maze discrimination learning and reversal learning, operant discrimination, and passive avoidance acquisition tasks. Ambulation in the open field was also measured. Small to moderate correlations between brain weight and learning measures were obtained for all tasks except passive avoidance. A moderate correlation between brain weight and activity was found only in the open field (r?=?.39). Partialing out differences in operant level and body weight had little effect on the magnitude of the correlations between brain weight and learning performance. When ambulation in the open field was partialed out, however, all correlations between brain weight and learning performance decreased. Previous research, as summarized in T. H. Roderick et al (1976), suggested a positive relation between brain weight and learning scores across mammalian orders and species. The present results extend this relation to within-species variation in brain size and emphasize the limitations of estimating genetic associations between brain and behavior from comparisons between small numbers of inbred strains or selected lines. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Incubation of creative performance and specific associative priming.

In the context of an associative theory of creativity, the effect of specific associative priming upon incubation of creative performance was studied. 2 experiments were conducted. In Experiment I, using 30 Ss, it was demonstrated that performance on a remote-associate task was enhanced by specific priming. In a 2nd study, using the same method and materials, high scores (HC) and low scorers (LC) on the Remote Associate Test (a measure of creative potential) were compared in a 2 X 2 X 3 factorial design also included 2 levels of priming (some and none) and 3 time relationships (immediate, pre-24 hr. and post-24 hr.) HC Ss performed significantly better than LC Ss, and the effect of specific priming was significantly greater than no priming. The time relationship had no effect. These data lend support to an associative interpretation of the phenomenon of incubation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of positron emission tomography for presurgical localization of eloquent brain areas in children with seizures

Successful surgical management of a neoplastic or nonneoplastic seizure focus in close proximity to or within eloquent brain areas relies on precise delineation of the relationship between the lesion and functional brain areas. The aim of this series was to validate the usefulness and test the efficacy of noninvasive presurgical PET mapping of eloquent brain areas to predict surgical morbidity and outcome in children with seizures. To identify eloquent brain areas in 15 children (6 female and 9 male; mean age 11 years) with epileptogenic lesions PET images of regional cerebral blood flow were performed following the administration of [(15)O]water during motor, visual, articulation, and receptive language tasks. These images with coregistered magnetic resonance (MR) images were then used to delineate the anatomic relationship of a seizure focus to eloquent brain areas. Additional PET images using [18F]fluoro-2-deoxy-D-glucose (FDG) and [11C]methionine (CMET) were acquired to help localize the seizure focus, as well as characterize the lesion. Patient surgical management decisions were based on PET mapping in combination with coregistered MR images, PET-FDG findings, and the anatomic characteristics of the lesion. At follow-up 1-26 months after surgery, all patients that underwent temporal lobectomy (9 patients) and extratemporal resection (4 patients) for a neoplastic or nonneoplastic seizure focus are seizure-free with minimal postoperative morbidity. Of prime importance, no child sustained a postoperative speech or language deficit. PET imaging was also well tolerated without procedural complications. Based on PET mapping, a nonoperative approach was used for 2 children and a biopsy only was used in one child. When cortical injury involved prenatally determined eloquent cortex, PET demonstrated reorganization of language areas to new adjacent areas or even to the contralateral hemisphere. Integration of anatomical and functional data enhanced the surgical safety, defined optimal surgical approach, delineated the seizure focus from eloquent brain areas, facilitated maximum resection and optimized the timing of surgery, thereby minimizing surgical morbidity while maximizing surgical goals. PET measurements of FDG and CMET uptake were also helpful in localizing the seizure focus and grading the tumors. PET used for brain mapping in children provides the surgeon with strategic preoperative information not readily attainable with traditional invasive Wada testing or intraoperative cortical stimulation. PET mapping may also improve the outcome of extratemporal resections by allowing aggressive seizure focus resection. In addition, serial brain maps may optimize timing for surgical intervention by demonstrating reorganization of eloquent cortex often seen in younger children after cortical injury. Our results suggest that noninvasive presurgical brain mapping has the potential to reduce risk and improve neurologic outcome.     

Are GAD65 and GAD67 associated with specific pools of GABA in brain?

The brainstem projections of sensory fibers of the lung were determined in the rat by using the horseradish peroxidase (HRP) and c-fos immunohistochemical methods. Wheat germ agglutinin conjugated HRP (WGA-HRP) was injected into the parenchyma of the upper lobe of the left lung. This injection resulted in anterograde labeling in the nucleus of the tractus solitarius (NTS), area postrema (AP) and external cuneate nucleus (ECu) with slightly ipsilateral predominance. It was of interest that these labeled sensory fibers are heavily accumulated in the medial subnucleus at the rostral pole of the NTS and in the commissural subnucleus at the caudal pole. In particular, labeled fibers in the medial subnucleus were characterized by division into the ventral and dorsal portions. After formalin was injected into the parenchyma of the upper lobe of the left lung, the expression of c-fos-like immunoreactivity (FOS-LI) was observed in three nuclei of the brainstem mentioned above. In addition, this experiment resulted in the expression in the ventrolateral medulla, nucleus raphe pallidus and dorsal motor nucleus of vagus nerve bilaterally. With respect to the number of the immunoreactive cells, we could draw the conclusion that the most optimum time to induce the expression of FOS-LI is between 1.5 h and 2.0 h after noxious stimuli.