Abstract not available

[by] Duncan H. Looney and Sanborn C. Brown. / "December 4, 1953." "Reprinted from the Physical review, vol. 93, no. 5, 965-969, March 1, 1954." / Includes bibliographical references. / Army Signal Corps Contract No. DA36-039 sc-100, Project 8-102B-0. Dept. of the Army Project No. 3-99-10-022.

Background: Gamma oscillations (30-80 Hz) in the dorsolateral prefrontal cortex (DLPFC) are associated with working memory; a process involving the maintenance and manipulation of information on line (Baddeley, 1986). Gamma oscillations are supported by gamma-aminobutyric acid (GABA) inhibitory interneurons in the DLPFC. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive method in which to stimulate the cortex that has been shown to modify oscillations, cognition and GABAergic mechanisms. Patients with schizophrenia have severe deficits in working memory that may be related to impairments in GABAergic inhibitory neurotransmission underlying gamma oscillations in the DLPFC. Objective: First, to evaluate gamma oscillatory activity in patients with schizophrenia during working memory compared to healthy subjects. Second, to examine the effect of rTMS applied over the DLPFC on gamma oscillations generated during working memory in healthy subjects. Third, to examine the effect of rTMS applied to the DLPFC on gamma oscillations in patients with schizophrenia compared to healthy subjects. Hypotheses: First, it was hypothesized that patients with schizophrenia would exhibit an alteration in gamma oscillatory activity. Second, it was hypothesized that rTMS would be effective in enhancing gamma oscillations in healthy subjects. Third, it was hypothesized that rTMS would be effective in inhibiting gamma oscillations in patients with schizophrenia. Results: The first study found that patients with schizophrenia generate excessive gamma oscillations during working memory compared to healthy subjects. The second experiment found that rTMS over the DLPFC resulted in the potentiation of gamma oscillations in healthy subjects during working memory. The third experiment demonstrated that rTMS inhibited excessive gamma oscillations in patients with schizophrenia while an opposite effect was found in healthy subjects. Conclusions: rTMS applied over the DLPFC modulates frontal gamma oscillatory in healthy subjects and in patients with schizophrenia depending on baseline levels of activity, a finding that may ultimately translate into a better understanding of the mechanisms leading to cognitive improvement in this disorder.

Background: Gamma oscillations (30-80 Hz) in the dorsolateral prefrontal cortex (DLPFC) are associated with working memory; a process involving the maintenance and manipulation of information on line (Baddeley, 1986). Gamma oscillations are supported by gamma-aminobutyric acid (GABA) inhibitory interneurons in the DLPFC. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive method in which to stimulate the cortex that has been shown to modify oscillations, cognition and GABAergic mechanisms. Patients with schizophrenia have severe deficits in working memory that may be related to impairments in GABAergic inhibitory neurotransmission underlying gamma oscillations in the DLPFC. Objective: First, to evaluate gamma oscillatory activity in patients with schizophrenia during working memory compared to healthy subjects. Second, to examine the effect of rTMS applied over the DLPFC on gamma oscillations generated during working memory in healthy subjects. Third, to examine the effect of rTMS applied to the DLPFC on gamma oscillations in patients with schizophrenia compared to healthy subjects. Hypotheses: First, it was hypothesized that patients with schizophrenia would exhibit an alteration in gamma oscillatory activity. Second, it was hypothesized that rTMS would be effective in enhancing gamma oscillations in healthy subjects. Third, it was hypothesized that rTMS would be effective in inhibiting gamma oscillations in patients with schizophrenia. Results: The first study found that patients with schizophrenia generate excessive gamma oscillations during working memory compared to healthy subjects. The second experiment found that rTMS over the DLPFC resulted in the potentiation of gamma oscillations in healthy subjects during working memory. The third experiment demonstrated that rTMS inhibited excessive gamma oscillations in patients with schizophrenia while an opposite effect was found in healthy subjects. Conclusions: rTMS applied over the DLPFC modulates frontal gamma oscillatory in healthy subjects and in patients with schizophrenia depending on baseline levels of activity, a finding that may ultimately translate into a better understanding of the mechanisms leading to cognitive improvement in this disorder.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 158-167). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 158-167). Also available on the Internet.

MINOS is a long-baseline two-detector neutrino oscillation experiment that uses a high intensity muon neutrino beam to investigate the phenomena of neutrino oscillations. The neutrino beam is produced by the NuMI facility at Fermilab, Batavia, Illinois, and is observed at near and far detectors placed 734 km apart. The neutrino interactions in the near detector are used to measure the initial muon neutrino flux. The vast majority of neutrinos travel through the near detector and Earth matter without interactions. A fraction of muon neutrinos oscillate into other flavors resulting in the disappearance of muon neutrinos at the far detector. This thesis presents a measurement of the muon neutrino oscillation parameters in the framework of the two-neutrino oscillation hypothesis. / text

A CA1 pyramidal neuron in the rodent hippocampus integrates inputs from as many as 30,000 synapses distributed over hundreds of microns, making synaptic integration an intricate spatio-temporal computation. Crucial to this computation, is the timing of synaptic inputs at the axo-somatic integration site. Consequently, it would be beneficial if co-incident proximal and distal inputs arrive simultaneously at the axo-somatic integration site. This, however, is a challenge considering that spatially dispersed inputs have to propagate varying distances, leading to location-dependent temporal differences at the soma. Here we show that CA1 pyramidal neurons have an intrinsic biophysical mechanism in the form of a gradient of HCN channels that actively counteracts location-dependent temporal differences of dendritic inputs at the soma. HCN channels, due to their slow kinetics and unusual gating properties, impart an inductive reactance to the neuronal membrane properties. Using multi-site whole cell recordings, we show that this gradient of inductive reactance actively compensates for the location-dependent capacitive delay of dendritic inputs. This leads to a response synchrony of spatially dispersed inputs at the soma. This response synchrony is optimum for oscillatory signals in the theta frequency range (4-12 Hz). Using computational modeling we show that the characteristic sigmoidal distribution of HCN channels in CA1 neurons is crucial for the efficient and exclusive transfer of these synchronous theta frequencies from dendrite to the soma. To understand the significance of this oscillatory synchrony during synaptic integration, we used the dynamic clamp technique to simulate different temporal patterns of synaptic input in the dendrites of CA1 neurons. Our results reveal that this oscillatory synchrony is best harnessed by theta and gamma (40-140 Hz) frequency synaptic input patterns in CA1 neurons. Gamma and theta oscillations are associated with synchronizing activity across space in the hippocampal network. Our results thus identify a novel mechanism by which this synchrony extends to activity within single pyramidal neurons with complex dendritic arbors. / text

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