Biomedical subjects

M A Persinger

Publications and source records attributed to M A Persinger.

At least 163 records · Page 9Linked to original sources

PubMed1995

Physiological and cognitive correlates of child abuse.

OBJECTIVE: To compare the physiological responses of abused children to different stimuli with responses of children in a reference group and to correlate the physiological responses with intellectual and personality functioning. METHOD: Abused children were compared with a reference group on two batteries of tests that were administered on separate days. In one session, children were shown slides with emotional or cognitive content while heart rate, pulse height, skin conductance, electromyography, and skin temperature were measured. In the other session, intellectual and personality functioning was measured using the WISC-R, Quick Neurological Screening Test, and the Junior Eysenck personality inventory. RESULTS: Abused children had smaller changes in pulse height in the first two stimulus conditions presented ("No Signal" and "Math"), but their electrodermal responses were lower throughout all stimulus conditions. Abused children also had higher introversion and lower Verbal and Full Scale IQ scores. Verbal and Full Scale IQ scores were inversely related to the severity of abuse that had been experienced. When these variables were used in a discriminant function analysis, children were assigned to the correct group 86% of the time. CONCLUSION: These findings support a model that describes the effects of abuse as delaying cognitive development and inhibiting physiological responsiveness to the environment.

Adolescent↗

PubMed1995

Association between intermale social aggression and cellular density within the central amygdaloid nucleus in rats with lithium/pilocarpine-induced seizures.

Aggressive behaviors (numbers of bites/hour) within groups (ns = 8) of normal rats and rats in which seizures had been induced by a single systemic injection of lithium/pilocarpine were observed for 11 successive, 1-hr, periods. Mean numbers of neurons and glial cells were counted for 10 different nuclei of the amygdala for 16 different brains (8 control; 8 seizure). Although there was no significant difference found between rats with chronically induced seizures and controls for the numbers of neurons per area within the central medial amygdaloid nucleus, the neuronal density was correlated significantly (.92) with mean numbers of bites per hour for the chronically epileptic group only. The hypothesis that seizure-induced damage within proximal amygdaloid nuclei disinhibits the central nucleus and encourages aggression was supported.

Aggression↗

PubMed1995

Women reconstruct more details than men for a complex five-minute narrative: implications for right-hemispheric factors in the serial memory effect.

A total of 20 men and 20 women listened to a 5-min. ambiguous narrative (the "Billy" story). When the subjects were asked (unexpectedly) to reconstruct the details of the story as a written narrative 30 min. later, women employed about 50% more words and comparably more accurate detail than the men. Covariance for pre-experimental experiences suggested that the women's proficiency could be related to the greater representation of linguistic processes within the right (non-dominant) hemisphere. The hypothesis that the classic deficit of reconstructional accuracy for events during the middle of a story is related to right-hemispheric inhibition was also supported. Subjects who recalled the fewest details reported more vivid dreaming during the subsequent two days.

Adult↗

PubMed1995

Complex partial epileptic-like signs contribute differential sources of variance to low self-esteem and imaginings.

64 university men and 55 university women displayed correlations (r = 0.40) between two psychometric inventories that have been employed to study subclinical complex partial epileptic-like signs in normal and traumatically brain-injured people. Although psychometric inferences of self-esteem and reports of childhood memories and imaginings were not significantly associated, both indicators of complex partial epileptic-like signs showed significantly positive associations with fantasy-prone behavior but significantly negative correlations with self-esteem. Subsequent analyses supported the vectorial hemisphericity model that elevated mesiobasal limbic activity may enhance imaginings while frequent intrusions into awareness of right-hemispheric indicators would be also associated with lower self-esteem. Lower self-esteem was correlated significantly with reported fears and phobias for the women but not for the men.

Adult↗

PubMed1995

Out-of-body-like experiences are more probable in people with elevated complex partial epileptic-like signs during periods of enhanced geomagnetic activity: a nonlinear effect.

The ratings of subjective experiences of the self "leaving" or of being detached from the body were obtained (over a 3-yr. period) for a total of 128 men and women who had been exposed only once to an experimental setting which enhances the awareness of cognitive processes. As hypothesized, the individuals who exhibited the greatest proportion of complex partial epileptic-like signs also reported the most intense experiences of detachment from the body; however, these occurred primarily when the geomagnetic activity on the day of the experiment exceeded about 15 nT but was less than about 45 nT. Geomagnetic activity for the day after or the three days before the experiment was not associated with these experiences. The effect was equivalent to a correlation coefficient (eta) of .38.

Adult↗

PubMed1995

Foot agility and toe gnosis/graphaesthesia as potential indicators of integrity of the medial cerebral surface: normative data and comparison with clinical populations.

A protocol was designed to identify quantitative indicators of the function of the medial surfaces of the cerebral hemispheres. Normative data were collected from 40 volunteers for foot agility, toe gnosis, and toe graphaesthesia. A total of 100 patients (most of whom had been referred for possible closed-head injuries) completed thorough neuropsychological and cognitive assessments. Deficits for toe graphaesthesia were most consistently correlated with general brain impairment and with scores for tasks whose normal performance requires the integrity of structures within the dorsal half of the medial cerebral hemispheres.

Adolescent↗

PubMed1995

On the possibility of directly accessing every human brain by electromagnetic induction of fundamental algorithms.

Contemporary neuroscience suggests the existence of fundamental algorithms by which all sensory transduction is translated into an intrinsic, brain-specific code. Direct stimulation of these codes within the human temporal or limbic cortices by applied electromagnetic patterns may require energy levels which are within the range of both geomagnetic activity and contemporary communication networks. A process which is coupled to the narrow band of brain temperature could allow all normal human brains to be affected by a subharmonic whose frequency range at about 10 Hz would only vary by 0.1 Hz.

Algorithms↗

PubMed1995

Geophysical variables and behavior: LXXIX. Overt limbic seizures are associated with concurrent and premidscotophase geomagnetic activity: synchronization by prenocturnal feeding.

Approximately 35% of the variance (multiple r = 0.59) in the proportion of overt seizures (forelimb clonus) within a group of 35 chronically epileptic male rats during 65, daily 10-min. observation periods was significantly accommodated by the variations in the magnitude of the increased geomagnetic activity at the same time as the seizures and with activity during the previous midscotophase. The results supported the hypothesis that increased geomagnetic activity during specific subintervals of the circadian period suppresses the activity of the endogenous anticonvulsant melatonin and lowers the threshold for paroxysmal electrical seizures. The possibility of employing large populations of (limbic) epileptic patients as a network or a very large array of biomonitors for geomagnetic activity is considered.

Amygdala↗

PubMed1995

Clinical neurological indicators are only moderately correlated with quantitative neuropsychological test scores in patients who display mild-moderate brain impairment following closed-head injuries.

Quantitative comparisons were completed between mean scores for standardized neuropsychological tests (requiring 6 hr.), numbers of neurological signs (tests requiring 15 min.), anomalies within the electroencephalogram, subjective symptoms during a structured interview (requiring 20 min.), and an indicator of an organic brain syndrome for 81 patients who had sustained significant mechanical impacts to their skulls. The composite of neuropsychological scores was correlated 0.70 with a composite of neurological indicators and EEG anomalies. There were no significant correlations between neuropsychological or neurological scores and the numbers of subjective complaints, abnormal personality indicators, duration of coma or the interval of posttraumatic dysmnesia. However, the scores for the severity of the organic brain syndrome, partial complex epileptic symptoms, and subjective complaints were inversely correlated (rho = -0.35) with the duration of coma, the period of posttraumatic amnesia, and the numbers of qualitative electroencephalographic anomalies.

Adolescent↗

PubMed1995

Early genital stimulation of rats lowers limbic seizure latencies for females but increases latencies for males.

The genitals of male and female rats were tactilely stimulated (glass rod) for 10 successive days beginning on postnatal Days 5, 15, 35; handled but nonstimulated litter mates served as the reference groups. Limbic seizures were induced by a single systemic injection of lithium and pilocarpine when the rats were adults. The genitally stimulated female rats displayed a lower seizure threshold (as inferred from shorter seizure-onset times) relative to their cage mates. The single largest effect occurred for those females which had been stimulated after the vagina had opened (postnatal 35-45 days).

Animals↗

PubMed1995

Prednisolone blocks extreme intermale social aggression in seizure-induced, brain-damaged rats: implications for the amygdaloid central nucleus, corticotrophin-releasing factor, and electrical seizures.

In two separate blocks of experiments, the extreme within-group aggression which is typically associated with limbic seizure-induced brain injury in male rats was attenuated or abolished within two days by the administration of prednisolone in the water supply. The effect was specific to the aggression and was not simulated by dexamethasone. The results support the hypothesis that interference with inhibitory inputs to the central nucleus of the amygdala and the enhanced stimulation by corticotrophin-releasing factor facilitates physical aggression within groups of male rats. Potential relevance to curbing aggression ("conflict") between groups of male humans is discussed.

Aggression↗

PubMed1995

Neuropsychological principia brevita: an application to traumatic (acquired) brain injury.

The concepts and discoveries of modern neuroscience now challenge many of the presumptions that influence diagnostic decisions within neurology, psychiatry, and clinical neuropsychology. Many of these presumptions are derived from archaic bivariate models such as the mind-body argument, organic-functional dichotomy, and single lesion-single behaviour causality. Thirteen basic principles which may be useful for inferring more reliable and accurate relationships between microstructural function an clinical manifestations are developed.

Brain↗

PubMed1994

Concordance of quantitative damage within the diencephalon and telencephalon following systemic pilocarpine (380 mg/kg) or lithium (3 mEq/kg)/pilocarpine (30 mg/kg) induced seizures.

We tested the hypothesis that a single systemic injection of 380 mg/kg of the muscarinic agonist pilocarpine would produce more diffuse and severe seizure-induced brain damage than a single injection of lithium (3 mEq/kg) followed 4 h later by < 1/10 the dosage of pilocarpine. The hypothesis was not supported; the pattern of quantitative brain damage 50-60 days after the seizures were elicited by either treatment was comparable within the limits of measurement error. Within the diencephalon and subcortical telencephalon the same structures were either damaged in a similar quantitative manner or were spared. Only five of the 119 damaged structures exhibited statistically significant treatment differences at P < 0.01. The results are compatible with the explanation that lithium may enhance the excitotoxic effects of subsequent muscarinic stimulation.

Acepromazine↗

PubMed1994

Prevention of sudden cardiac death by the atypical neuroleptic acepromazine following status epilepticus in rats.

Normal male rats in which status epilepticus has been induced by injecting 30 mg/kg of pilocarpine after a single systemic administration of lithium (sufficient to produce blood levels of 0.2 mEq/L) invariably die within 24 hr. Real-time monitoring indicated sudden cardiac death; it was preceded by progressive intensification of arrhythmia. A single systemic injection (25 mg/kg) of the atypical phenothiazine acepromazine prevented the mortality and virtually eliminated the cardiac instability.

Acepromazine↗

PubMed1994

Dissociation between conditioned taste aversion and radial maze learning following seizure-induced multifocal brain damage: quantitative tests of serial vs. parallel circuit models of memory.

Multivariate analyses between conditioned taste aversion (CTA) and radial maze acquisition (RMA) scores and percentages of neuronal dropout within thalamic and telencephalic structures were completed for rats in which overt seizures had been evoked following a single systemic injection of lithium/pilocarpine. Despite multifocal damage, only the amount of damage within the hippocampus (CA1) and the basolateral amygdala was most strongly associated with attenuated CTA, whereas damage within the mediodorsal thalamus was primarily associated with RMA. There was no significant correlation between CTA or RMA. Multiple regression analyses for specific Paxinos and Watson structures and their traditional aggregates supported more precise delineation of neuronal substrates of learning/memory and a multimodal (parallel) model for these processes.

Animals↗

PubMed1994

Seizure suggestibility may not be an exclusive differential indicator between psychogenic and partial complex seizures: the presence of a third factor.

Differential diagnosis between psychogenic or ('hysterical') pseudoseizures and clinical partial complex seizures has often employed an index or inference of suggestibility. However, recent research indicates a moderate association between complex partial epileptic-like signs and hypnotic capacity in the normal population as well as for complex partial epileptic patients. Consequently, the precipitation of overt, non-stereotyped seizures by instruction may not be a reliable diagnostic method when an insidious process is slowly elevating temporal/limbic lobe lability. Implications for treatment and contra-indication of antipsychotic (D2 antagonist) drugs are discussed.

Anticonvulsants↗

PubMed1994

The Dichotic Word Listening Test: preliminary observations in American and Canadian samples.

The present article describes observations of 670 American and Canadian child and adult control subjects on the recently developed Dichotic Word Listening Test (DWLT). The task was also administered to a sample of American children with traumatic brain injuries (n=21) of varying severity and a sample of American adults with mild traumatic injuries (n=36). The conceptual focus in this line of research was on using normative observations to identify clinically defective channels of auditory processing among patients. The principal findings were as follow: 1) the DWLT was sensitive to the effects of cerebral dysfunction following traumatic brain injury; 2) differences among normal samples with different demographic backgrounds were frequently observed, arguing for the development of local norms; 3) a shorter form of the DWLT task (DWLT30) can be used for screening purposes with relatively little reduction in sensitivity to cerebral dysfunction; 4) there appeared to be considerable improvement of DWLT performance between the ages of five and seven, due largely to higher scores from the left auditory channel; and 5) there were indications that use of French (rather than English) as one's native language before age six can negatively influence performance in adulthood on an English version of the DWLT. In general, the present findings suggest that the DWLT is likely to have relatively broad applicability for neuropsychological assessment across the life-span.

Journal Article↗

PubMed1994

Elicitation of "childhood memories" in hypnosis-like settings is associated with complex partial epileptic-like signs for women but not for men: implications for the false memory syndrome.

20 male and 20 female undergraduate students were exposed singly for 20 min. to an exotic setting (partial sensory deprivation and weak, bilateral transtemporal pulsed magnetic fields) that enhances relaxation and exotic experiences. The numerical incidence of subjective experiences described as old memories, dreams, emotions, or vestibular sensations did not differ significantly between the sexes; however, women who reported a greater prevalence of preexperimental complex partial epileptic-like signs were more likely to report experiences of "old memories" (r = 0.61) while men who exhibited these signs were more likely to report dream-like (r = 0.49) experiences. Because complex partial epileptic-like signs are positively associated with suggestibility, the potential contribution of this differential gender effect to the etiology of the False Memory Syndrome requires further investigation.

Adolescent↗