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M Reite

Publications and source records attributed to M Reite.

At least 37 records · Page 2Linked to original sources
PubMed1995

MEG based brain laterality: sex differences in normal adults.

Magnetoencephalographic (MEG) auditory evoked fields produced by short tone pips were recorded from 34 normal adults (17 males, 17 females) and the 100 msec latency component (M100) localized in left and right hemispheres. Absolute M100 location in the antero-posterior dimension was calculated for each subject. M100 sources were significantly further anterior in the right hemisphere of males. Magnetic resonance (MR) based anatomy of the superior temporal gyri (STG) in a subset of 17 subjects showed that in the left STG of both males and females M100 sources were located approximately midway on the STG. In the right hemisphere of males, however, M100 sources were significantly further anterior on the STG than was the case for females. The findings are compatible with a sex based difference in right STG functional anatomy, with evidence of greater hemispheric lateralization in males compared to females based upon a predominantly right hemisphere contribution.

Adult↗
PubMed1995

Schizophrenia may alter neuromagnetic representations of attention.

When male paranoid schizophrenic subjects attended to a dichotic oddball task requiring target discrimination, their 100-ms latency left hemisphere magnetic auditory sources did not increase in strength, and their source geometry appeared to be degraded, rather than enhanced, compared with normal control subjects, implicating abnormal processing in the superior temporal gyrus.

Adult↗
PubMed1994

Sleep inducing effect of low energy emission therapy.

The sleep inducing effect of a 15 min treatment with either an active or an inactive Low Energy Emission Therapy (LEET) device emitting amplitude-modulated electromagnetic (EM) fields was investigated in a double-blind cross-over study performed on 52 healthy subjects. All subjects were exposed to both active and inactive LEET treatment sessions, with an interval of at least 1 week between the two sessions. LEET consists of 27.12 MHz amplitude-modulated (sine wave) EM fields emitted intrabuccally by means of an electrically conducting mouthpiece in direct contact with the oral mucosa. The estimated local peak SAR is less than 10 W/kg in the oral mucosa and 0.1 to 100 mW/kg in brain tissue. No appreciable sensation is experienced during treatment, and subjects are therefore unable to tell whether they are receiving an active or an inactive treatment. In this study the active treatment consisted of EM fields intermittently amplitude-modulated (sine wave) at 42.7 Hz for 3 s followed by a pause of 1 s during which no EM fields were emitted. During the inactive treatment no EM fields were emitted. Baseline EEGs were obtained and 15 min post-treatment EEGs were recorded and analyzed according to the Loomis classification. A significant decrease (paired t test) in sleep latency to stage B2 (-1.78 +/- 5.57 min, P = 0.013), and an increase in the total duration of stage B2 (1.15 +/- 2.47 min, P = 0.0008) were observed on active treatment as compared with inactive treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Magnetic auditory source imaging in macaque monkey.

We recorded magnetic auditory evoked fields from the left hemisphere of a 2-year-old 3.4 kg Macaca nemestrina monkey. Three separate components were isolated from each of three data sets with latencies of approximately 22 ms, 46 ms, and 130 ms after stimulus onset. The 46 ms latency component had clear extrema values and was selected for localization. Field values from 21 recording points were used to estimate the 3-D source location of the 46 ms latency component, termed the M46. High resolution MR images of the brain provided information for correlation of neuroanatomic structure with source location. The neuroanatomic source was found to lie in the superior aspect of the temporal lobes bilaterally. We believe the M46 is the macaque analog of the human M100. Recording of auditory evoked fields in nonhuman primates offers a valuable animal model for studying neurophysiology of human magnetoencephalographically (MEG) determined auditory sources.

Acoustic Stimulation↗
PubMed1994

Auditory M100 component 1: relationship to Heschl's gyri.

This study was designed to localize the neuroanatomic generator of the 100 ms latency magnetic auditory evoked field (EF) component (M100) activated by an unattended tone pip. Magnetic EFs in response to 25 ms duration, 90 dB, 1 kHz tone pips were recorded from both hemispheres of nine normal adults, five males and four females, using a seven-channel second-order gradiometer. The source of the M100 was estimated, with confidence intervals, by a least squares based inverse solution algorithm. Magnetic resonance (MR) images of the brain were acquired with a 1.5 T system using a standard head coil. The superior temporal gyri (STG) were manually segmented from 1.7 mm thick coronal images, and the superior surfaces were then rendered from the 3-D volume data. Translation and rotation matrices were identified to locate the magnetoencephalography (MEG) determined sources within the reconstructed STGs. This population of 18 STGs in 9 individuals demonstrated two transverse gyri in 4 of 9 left hemispheres, and 5 of 9 right hemispheres. All 9 left hemisphere M100 sources were in or included Heschl's gyrus(i) in the confidence intervals. Seven of the 9 included Heschl's gyrus(i) on the right: the remaining two, both males, had sources slightly anterior to Heschl's gyrus(i). We conclude that all M100 source location estimates were compatible with an auditory koniocortex source in or adjacent to Heschl's gyri.

Adult↗
PubMed1993

Neuropsychological test performance and MEG-based brain lateralization: sex differences.

Magnetoencephalographic (MEG) auditory evoked fields (EF) were recorded from left and right hemispheres of 9 normal males and 12 normal females. Source location of the 100 ms latency component (M100) was localized to superior temporal lobes bilaterally using an inverse solution algorithm. All subjects also were administered the Wechsler block design and visual reproduction subtests, and the California Verbal Learning Test (CVLT). M100 source locations demonstrated significant sex differences in interhemispheric asymmetry. Males had source locations further anterior than females, with the differences most pronounced in the right hemisphere. Expected sex differences were found in neuropsychological test performance, with males performing better on block design ad visual reproduction, and females performing better on the CVLT. Across both sexes, block design scores correlated significantly with right hemisphere M100 location, with more anterior source locations associated with better performance. CVLT scores were negatively correlated with right hemisphere M100 source locations. These findings suggest MEG-based measures of interhemispheric asymmetry may be related to specific neuropsychological test performance measures.

Acoustic Stimulation↗
PubMed1992

Auditory magnetic source localization in twins.

We recorded magnetoencephalographic (MEG) auditory evoked fields (EF) from the L and R hemispheres of 12 paris of twins, 6 monozygotic (MZ), and 6 dizygotic (DZ) and localized the source of the 100 msec latency EF component termed the M100. M100 sources exhibited greater similarity in location in MZ twin pairs, especially in the L hemisphere. These findings support the hypothesis that the functional location of processing of nonmeaningful unattended auditory stimuli may depend more heavily on left hemisphere structures. Furthermore, genetic effects are evident in these left hemisphere structures and their activity, as is a substantial amount of environmental variance.

Acoustic Stimulation↗
PubMed1991

Minipump clorgyline administration and CSF amine metabolites in unrestrained monkeys.

The irreversible MAO-A inhibitor clorgyline was administered in doses of 0.5 mg/kg (N = 1), 1 mg/kg (N = 3), and 2 mg/kg (N = 1) to 5 young (age 5.5 to 23.9 months) pigtail (M. nemestrina) monkeys using a 28-day (Alza 2ML4) osmotic minipump. CSF MHPG, 5-HIAA, HVA, and plasma MHPG were measured before and at approximately weekly intervals after pump implantation. Implants were well tolerated. CSF MHPG decreased about 75%, 5-HIAA 30%, and HVA from 30-50% with a tendency to plateau by the second week. Plasma MHPG decreased to undetectable levels. The findings demonstrate that long-term inhibition of MAO-A can be produced in unrestrained monkeys by minipump administered clorgyline. There is an apparently greater effect on the norepinephrine system relative to the serotonin and dopamine systems.

Animals↗
PubMed1991

Magnetic auditory M100 source location in normal females.

We recorded magnetoencephalographic auditory evoked fields from the left and right hemispheres of six normal adult female subjects, in response to unattended tone pips. Magnetic field data was used to estimate location, orientation, depth, and strength of the 100-ms latency evoked field component (M100). M100 source locations did not significantly differ in left and right hemispheres. Previous studies in six normal males demonstrated M100 sources to be significantly further anterior in the right hemisphere. Compared to the previously reported male subjects, M100 sources in the right hemisphere of these females were significantly further posteriorly, by a mean value of 2.1 cm. These findings, while preliminary, support sex-related functional and/or structural differences in the superior temporal lobe, and would be compatible with the female right temporal planum extending further posteriorly. They suggest MEG recordings may be a useful addition to studies of sex-related difference in brain function and/or structure.

Adult↗
PubMed1989

Late auditory magnetic sources may differ in the left hemisphere of schizophrenic patients. A preliminary report.

We recorded magnetoencephalographic auditory evoked fields from the left and right hemispheres of six medicated, paranoid schizophrenic subjects and six normal controls. The magnetic field data were used in estimating the location, orientation, and depth of the source generating the 100-millisecond latency evoked field component (M100). The M100 latencies were slightly shorter than simultaneously recorded vertex electroencephalographic evoked potential N100 latencies, suggesting that magnetoencephalographic and electroencephalographic recordings were examining slightly different aspects of the source(s). The M100 sources demonstrated substantial interhemispheric asymmetry in normal controls, and were located more posteriorly, with more nearly vertical orientations, over the left hemisphere. The M100 sources in schizophrenics did not exhibit the same interhemispheric asymmetry. Left hemisphere source orientation differed significantly between normal controls and schizophrenics. Discriminant function analysis correctly classified normal controls and schizophrenics at 100% using the conservative jackknife procedure on the basis of left hemisphere orientation alone. Our findings, while preliminary, support altered left hemisphere function, or possibly structure, in this group of schizophrenic subjects, and suggest that magnetoencephalographic recordings may be a useful research method in this major mental illness.

Adult↗
PubMed1989

Behavioral and autonomic responses to peer separation in pigtail macaque monkey infants.

Brief maternal separations of young nonhuman primates have been used extensively to study the behavior and physiology of attachment, loss, and bereavement. The physiological responses to the loss of alternative attachment figures, such as peers, is less well documented in nonhuman primates. This study examined both autonomic and behavioral responses of peer-reared pigtail macaque infants to separation. Eight infants were removed from their mothers at birth and reared in four peer pairs. At 6 months of age, each monkey was implanted with a multichannel biotelemetry device which transmitted heartrate, body temperature, EEG, EMG, and EOG. Blood was collected twice weekly for immunological assessment. Behavioral and physiological data, including sleep, were collected for 1 week of baseline, 2 weeks of separation, and 1 week of reunion. Behavioral and physiological results indicated agitation but not depression following separation from their peer attachment figures. We found reduced mitogenic responses to pokeweed consequent to peer separation, suggestive of altered B-cell function. REM variables were the only sleep measures affected by the separation, and were suggestive of agitation but not depression.

Animals↗
PubMed1989

On the physiology of grooming in a pigtail macaque.

Several functions of social grooming have been proposed, including building affiliative bonds between group members, and reducing tension or anxiety. In this case study, heart rate (HR) of a single adult female pigtail macaque living in a social group was monitored in several behavioral contexts to examine the relationship between grooming and HR level, an indicator of autonomic nervous system activity. The subject was implanted as a part of another study with a multichannel telemetry system which monitored several physiological variables. Physiological and behavioral data were collected over a nine day period. Heart rate during agonistic interactions was significantly higher than during other categories of behavior, and sleep HR significantly lower. When the subject received grooming from others, HR was significantly lower than during self grooming or initiating grooming to others, as well as during other behaviors. HR showed significant declines during bouts of receiving groom (up to 20 bpm), but not during bouts of initiating or self grooming. Following aggression, HR decline was greatest while receiving grooming. There were also HR differences for methods of grooming: stroking but not other methods related to decreases in HR.

Aggression↗
PubMed1989

Maternal separation in bonnet monkey infants: altered attachment and social support.

Maternal separation in young pigtail (M. nemestrina) monkeys results in an agitation-depression reaction that is a useful animal model of the behavioral and physiological consequences and separation and loss experiences in humans. In this study, 5 social-group-living bonnet (M. radiata) monkey infants were separated from their mothers for 4 days, and behavioral, physiological, and sleep-pattern changes were monitored. Behavioral and physiological changes were consistent with an agitation reaction. There was evidence of depression in both behavioral and physiological measures; these changes were not as pronounced as in pigtail infants, however. All infants were adopted by another adult female during separation. Our findings suggest that, in bonnet monkey infants, adoption by a female within the social group ameliorates the response to loss.

Animals↗
PubMed1988

Source origin of a 50-msec latency auditory evoked field component in young schizophrenic men.

We recorded auditory evoked magnetic fields in response to 128 15-msec duration 1-KHz tone pips from both hemispheres of 6 young schizophrenic men. Auditory evoked potentials were recorded conventionally from a vertex lead. The approximately 50-msec latency component was identified in both the magnetic (M50) and electroencephalographic (EEG) (P50) recordings. Isofield topographical contour maps were used to estimate M50 source location and depth. Magnetic resonance imaging was used to identify the neuroanatomical structure(s) present at the estimated source location. M50 sources appeared to reside in the planum temporale in both left and right hemispheres in all subjects. Normal inter-hemispheric asymmetry (with respect to external bony landmarks) of the M50 source was not found in this patient group. Additionally, left (but not right) hemisphere source anatomy differed in several respects from data previously reported in normals.

Adult↗
PubMed1988

Source location of a 50 msec latency auditory evoked field component.

We recorded auditory evoked magnetic fields in response to 128 15 msec duration 1 kHz tone pips from both hemispheres of 6 normal adult males. Auditory evoked potentials were recorded conventionally from a vertex lead. An approximately 50 msec latency component was identified in both the magnetic (called the M50) and EEG (called the P50) recordings. Isofield topographical contour maps were used to estimate M50 source location and depth. With respect to extracranial bony landmarks, M50 source locations were significantly higher and tended to be more posterior, over the left hemisphere. M50 and P50 latencies were not significantly different in 5 of 6 subjects; in one, M50 latencies were significantly longer than P50 latencies over the left hemisphere. Magnetic resonance images in 5 subjects were used to identify the neuroanatomical structure(s) present at the estimated source location. M50 sources appeared to reside in the cortex of the planum temporale in both left and right hemispheres in all 5 subjects.

Adult↗