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2006

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Full-Text Articles in Neurosciences

Hormone Effects On Fmri And Cognitive Measures Of Encoding: Importance Of Hormone Preparation, C. E. Gleason, T. W. Schmitz, T. Hess, R. L. Koscik, M. A. Trivedi, M. L. Ries, C. M. Carlsson, M. A. Sager, S. Asthana, S. C. Johnson Dec 2006

Hormone Effects On Fmri And Cognitive Measures Of Encoding: Importance Of Hormone Preparation, C. E. Gleason, T. W. Schmitz, T. Hess, R. L. Koscik, M. A. Trivedi, M. L. Ries, C. M. Carlsson, M. A. Sager, S. Asthana, S. C. Johnson

Brain and Mind Institute Researchers' Publications

We compared fMRI and cognitive data from nine hormone therapy (HT)-naive women with data from women exposed to either opposed conjugated equine estrogens (CEE) (n = 10) or opposed estradiol (n = 4). Exposure to either form of HT was associated with healthier fMRI response; however, CEE-exposed women exhibited poorer memory performance than either HT-naive or estradiol-exposed subjects. These preliminary findings emphasize the need to characterize differential neural effects of various HTs. ©2006AAN Enterprises, Inc.


Narcotic Analgesics For Acute Migraine In The Emergency Room: Are We Meeting Headache Societies' Guidelines?, Mohammad Wasay, Khawaja Slaman Zaki, Saqib Uddin Khan, Rifat Rehmani Dec 2006

Narcotic Analgesics For Acute Migraine In The Emergency Room: Are We Meeting Headache Societies' Guidelines?, Mohammad Wasay, Khawaja Slaman Zaki, Saqib Uddin Khan, Rifat Rehmani

Department of Emergency Medicine

We analysed 161 patients with acute migraine in our emergency room (ER) to identify the use of narcotic analgesics as first-line treatment. Twenty-four percent of patients were treated with opioid analgesics and 76% patients were treated with non-opioid analgesics. Pain was completely relieved in 100 (62%) patients, partially relieved in 50 (31%) patients and was not relieved in 11 (7%) patients at the time of discharge. Pain relief was not related to the use of opioids vs. non-opioids. The treatment of acute migraine in our ER is in line with the guidelines of the Headache Societies and needs further improvement.


Soluble Amyloid Oligomers Increase Bilayer Conductance By Altering Dielectric Structure, Yuri Sokolov, J. Ashot Kozak, Rakez Kayed, Alexandr Chanturiya, Charles G. Glabe, James E. Hall Nov 2006

Soluble Amyloid Oligomers Increase Bilayer Conductance By Altering Dielectric Structure, Yuri Sokolov, J. Ashot Kozak, Rakez Kayed, Alexandr Chanturiya, Charles G. Glabe, James E. Hall

Neuroscience, Cell Biology & Physiology Faculty Publications

The amyloid hypothesis of Alzheimer's toxicity has undergone a resurgence with increasing evidence that it is not amyloid fibrils but a smaller oligomeric species that produces the deleterious results. In this paper we address the mechanism of this toxicity. Only oligomers increase the conductance of lipid bilayers and patch-clamped mammalian cells, producing almost identical current-voltage curves in both preparations. Oligomers increase the conductance of the bare bilayer, the cation conductance induced by nonactin, and the anion conductance induced by tetraphenyl borate. Negative charge reduces the sensitivity of the membrane to amyloid, but cholesterol has little effect. In contrast, the area …


Working Memory, Executive Functioning, And Children's Mathematics, R. Bull, K. A. Espy Nov 2006

Working Memory, Executive Functioning, And Children's Mathematics, R. Bull, K. A. Espy

Developmental Cognitive Neuroscience Laboratory: Faculty Publications

Approximately 3-6% of school-age children are estimated to have mathematics difficulties (Badian, 1983; Gross-Tsur, Manor, & Shalev, 1996; Kosc, 1974, Lewis, Hitch, & Walker, 1994). There are many more children in regular school classrooms who struggle with mathematics but whose performance is not considered sufficiently poor to be classified as meriting a specific disability in mathematics. Specific mathematic learning disability (MLD) is defined in psychiatric and educational venues as a large discrepancy between mathematics ability compared to reading and general intellectual ability, although the size of the discrepancy required varies. To further complicate matters, mathematic difficulties are associated with other …


Measuring The Development Of Executive Control With The Shape School, K. A. Espy, R. B. Bull, J Martin, W. Stroup Nov 2006

Measuring The Development Of Executive Control With The Shape School, K. A. Espy, R. B. Bull, J Martin, W. Stroup

Developmental Cognitive Neuroscience Laboratory: Faculty Publications

Although several neurodevelopmental and psychiatric disorders can emerge during the preschool period, there are comparatively few instruments to assess executive control. Evidence for validity of the Shape School (K. A. Espy, 1997) was examined in a sample of 219 typically developing young children. There was good evidence for validity, as Shape School performance variables were interrelated and were associated to other criterion measures considered to measure aspects of executive control. Also suggesting validity, the Shape School variables varied as a function of whether the task demands (a) were executive, (b) required inhibition of a prepotent response or context-controlled selection among …


Activation Of Brain Regions Vulnerable To Alzheimer's Disease: The Effect Of Mild Cognitive Impairment, S. C. Johnson, T. W. Schmitz, C. H. Moritz, M. E. Meyerand, H. A. Rowley, A. L. Alexander, K. W. Hansen, C. E. Gleason, C. M. Carlsson, M. L. Ries, S. Asthana, K. Chen, E. M. Reiman, G. E. Alexander Nov 2006

Activation Of Brain Regions Vulnerable To Alzheimer's Disease: The Effect Of Mild Cognitive Impairment, S. C. Johnson, T. W. Schmitz, C. H. Moritz, M. E. Meyerand, H. A. Rowley, A. L. Alexander, K. W. Hansen, C. E. Gleason, C. M. Carlsson, M. L. Ries, S. Asthana, K. Chen, E. M. Reiman, G. E. Alexander

Brain and Mind Institute Researchers' Publications

This study examined the functionality of the medial temporal lobe (MTL) and posterior cingulate (PC) in mild cognitive impairment amnestic type (MCI), a syndrome that puts patients at greater risk for developing Alzheimer disease (AD). Functional MRI (fMRI) was used to identify regions normally active during encoding of novel items and recognition of previously learned items in a reference group of 77 healthy young and middle-aged adults. The pattern of activation in this group guided further comparisons between 14 MCI subjects and 14 age-matched controls. The MCI patients exhibited less activity in the PC during recognition of previously learned items, …


Neuromechanics Of Multifunctionality During Rejection In Aplysia Californica, Hui Ye, Douglas W. Morton, Hillel J. Chiel Oct 2006

Neuromechanics Of Multifunctionality During Rejection In Aplysia Californica, Hui Ye, Douglas W. Morton, Hillel J. Chiel

Faculty Scholarship

How are the same muscles and neurons used to generate qualitatively different behaviors? We studied this question by analyzing the biomechanical and neural mechanisms of rejection responses in the marine mollusk Aplysia californica and compared these mechanisms with those used to generate swallowing responses (Ye et al., 2006). During rejection, the central grasper of the feeding structure closes to push inedible food out of the buccal cavity. This contrasts with swallowing, during which the grasper is open as it moves toward the jaws (protracts). We examined how the shape change of the grasper during rejection mechanically reconfigured the surrounding musculature. …


Genetic Bases Of Executive Control In Preschool Children: Trails-P Performance Is Related To Drd2 Genotype, S. A. Wiebe, M. Y. Chang, J. Huggenvik, T. Jameson, K. A. Espy Oct 2006

Genetic Bases Of Executive Control In Preschool Children: Trails-P Performance Is Related To Drd2 Genotype, S. A. Wiebe, M. Y. Chang, J. Huggenvik, T. Jameson, K. A. Espy

Developmental Cognitive Neuroscience Laboratory: Faculty Publications

Several studies link the D2 dopamine receptor (DRD2) with executive control and the ability to adapt behavior to changing contextual contingencies in human adults (Roesch-Ely 2005; Rodriguez-Jimenez 2006) and in animal models (Kruzich 2004). The present study examined relations between DRD2 and executive control in human development. Recently, a version of the Trail-Making Task suitable for preschool children was developed, which does not require knowledge of letters or numbers (TRAILS-P; Espy 2004). The Trail-Making Test is a neuropsychological test sensitive to frontal or executive dysfunction (Reitan 1955) where subjects must connect stimuli on a page in sequence, connecting letters only …


Structural Mri Discriminates Individuals With Mild Cognitive Impairment From Age-Matched Controls: A Combined Neuropsychological And Voxel Based Morphometry Study, Mehul A. Trivedi, Allison K. Wichmann, Britta M. Torgerson, Michael A. Ward, Taylor W. Schmitz, Michele L. Ries, Rebecca L. Koscik, Sanjay Asthana, Sterling C. Johnson Oct 2006

Structural Mri Discriminates Individuals With Mild Cognitive Impairment From Age-Matched Controls: A Combined Neuropsychological And Voxel Based Morphometry Study, Mehul A. Trivedi, Allison K. Wichmann, Britta M. Torgerson, Michael A. Ward, Taylor W. Schmitz, Michele L. Ries, Rebecca L. Koscik, Sanjay Asthana, Sterling C. Johnson

Brain and Mind Institute Researchers' Publications

Background: Several previous studies have reported that amnestic mild cognitive impairment (aMCI), a significant risk factor for Alzheimer's disease (AD), is associated with greater atrophy in the medial temporal lobe (MTL) and posterior cingulate gyrus (PCG). Method: In the present study, we examined the cross-sectional accuracy (i.e., the sensitivity and specificity) of voxel-based morphometry (VBM) in discriminating individuals with MCI (n = 15) from healthy age-matched controls (n = 15). In addition, we also sought to determine whether baseline GM volume predicted aMCI patients that converted to AD from those that did not approximately 2 years after the baseline visit. …


Unlv Magazine, Cate Weeks, Shane Bevell, Erin O'Donnell, Eric Leake, Lori Bachand, David G. Schwartz, David Ashley Oct 2006

Unlv Magazine, Cate Weeks, Shane Bevell, Erin O'Donnell, Eric Leake, Lori Bachand, David G. Schwartz, David Ashley

UNLV Magazine

No abstract provided.


Paradoxical Facilitation Of Object Recognition Memory After Infusion Of Scopolamine Into Perirhinal Cortex: Implications For Cholinergic System Function., Boyer D Winters, Lisa M Saksida, Timothy J Bussey Sep 2006

Paradoxical Facilitation Of Object Recognition Memory After Infusion Of Scopolamine Into Perirhinal Cortex: Implications For Cholinergic System Function., Boyer D Winters, Lisa M Saksida, Timothy J Bussey

Brain and Mind Institute Researchers' Publications

The cholinergic system has long been implicated in learning and memory, yet its specific function remains unclear. In the present study, we investigated the role of cortical acetylcholine in a rodent model of declarative memory by infusing the cholinergic muscarinic receptor antagonist scopolamine into the rat perirhinal cortex during different stages (encoding, storage/consolidation, and retrieval) of the spontaneous object recognition task. Presample infusions of scopolamine significantly impaired object recognition compared with performance of the same group of rats on saline trials; this result is consistent with previous reports supporting a role for perirhinal acetylcholine in object information acquisition. Scopolamine infusions …


Combining An Autologous Peripheral Nervous System “Bridge” And Matrix Modification By Chondroitinase Allows Robust, Functional Regeneration Beyond A Hemisection Lesion Of The Adult Rat Spinal Cord, John D. Houle, Veronica J. Tom, Debra A. Mayes, Gail Wagoner, Napoleon Phillips, Jerry Silver Jul 2006

Combining An Autologous Peripheral Nervous System “Bridge” And Matrix Modification By Chondroitinase Allows Robust, Functional Regeneration Beyond A Hemisection Lesion Of The Adult Rat Spinal Cord, John D. Houle, Veronica J. Tom, Debra A. Mayes, Gail Wagoner, Napoleon Phillips, Jerry Silver

Neuroscience, Cell Biology & Physiology Faculty Publications

Chondroitinase-ABC (ChABC) was applied to a cervical level 5 (C5) dorsal quadrant aspiration cavity of the adult rat spinal cord to degrade the local accumulation of inhibitory chondroitin sulfate proteoglycans. The intent was to enhance the extension of regenerated axons from the distal end of a peripheral nerve (PN) graft back into the C5 spinal cord, having bypassed a hemisection lesion at C3. ChABC-treated rats showed (1) gradual improvement in the range of forelimb swing during locomotion, with some animals progressing to the point of raising their forelimb above the nose, (2) an enhanced ability to use the forelimb in …


Representation Of Head-Centric Flow In The Human Motion Complex., Jeroen Goossens, Sean P Dukelow, Ravi S Menon, Tutis Vilis, Albert V Van Den Berg May 2006

Representation Of Head-Centric Flow In The Human Motion Complex., Jeroen Goossens, Sean P Dukelow, Ravi S Menon, Tutis Vilis, Albert V Van Den Berg

Brain and Mind Institute Researchers' Publications

Recent neuroimaging studies have identified putative homologs of macaque middle temporal area (area MT) and medial superior temporal area (area MST) in humans. Little is known about the integration of visual and nonvisual signals in human motion areas compared with monkeys. Through extra-retinal signals, the brain can factor out the components of visual flow on the retina that are induced by eye-in-head and head-in-space rotations and achieve a representation of flow relative to the head (head-centric flow) or body (body-centric flow). Here, we used functional magnetic resonance imaging to test whether extra-retinal eye-movement signals modulate responses to visual flow in …


Self-Appraisal Decisions Evoke Dissociated Dorsal-Ventral Ampfc Networks, Taylor W. Schmitz, Sterling C. Johnson Apr 2006

Self-Appraisal Decisions Evoke Dissociated Dorsal-Ventral Ampfc Networks, Taylor W. Schmitz, Sterling C. Johnson

Brain and Mind Institute Researchers' Publications

The anterior medial prefrontal cortex (aMPFC) is consistently active during personally salient decisions, yet the differential contributory processes of this region along the dorsal-ventral axis are less understood. Using a self-appraisal decision-making task and functional magnetic resonance imaging, we demonstrated task-dependent connectivity of ventral aMPFC with amygdala, insula, and nucleus accumbens, and dorsal aMPFC connectivity with dorsolateral PFC and bilateral hippocampus. These aMPFC networks appear to subserve distinct contributory processes inherent to self-appraisal decisions, specifically a dorsally mediated cognitive and a ventrally mediated affective/self-relevance network. © 2005 Elsevier Inc. All rights reserved.


Fibrinogen-Containing Y Chains; Is The Assay Measuring What Farrell's Group Expects?, Kevin R. Siebenlist Apr 2006

Fibrinogen-Containing Y Chains; Is The Assay Measuring What Farrell's Group Expects?, Kevin R. Siebenlist

Biomedical Sciences Faculty Research and Publications

No abstract provided.


Neuromechanics Of Coordination During Swallowing In Aplysia Californica, Hui Ye, Douglas W. Morton, Hillel J. Chiel Feb 2006

Neuromechanics Of Coordination During Swallowing In Aplysia Californica, Hui Ye, Douglas W. Morton, Hillel J. Chiel

Faculty Scholarship

Bernstein (1967) hypothesized that preparation of the periphery was crucial for correct responses to motor output. To test this hypothesis in a behaving animal, we examined the roles of two identified motor neurons, B7 and B8, which contribute to feeding behavior in the marine mollusk Aplysia californica. Neuron B7 innervates a hinge muscle and has no overt behavioral effect during smaller-amplitude (type A) swallows, because the hinge muscle is too short to exert force. Neuron B8 activates a muscle (I4) that acts solely to grasp material during type A swallows. During larger-amplitude (type B) swallows, the behavioral actions of both …


Task-Dependent Posterior Cingulate Activation In Mild Cognitive Impairment, Michele L. Ries, Taylor W. Schmitz, Tisha N. Kawahara, Britta M. Torgerson, Mehul A. Trivedi, Sterling C. Johnson Jan 2006

Task-Dependent Posterior Cingulate Activation In Mild Cognitive Impairment, Michele L. Ries, Taylor W. Schmitz, Tisha N. Kawahara, Britta M. Torgerson, Mehul A. Trivedi, Sterling C. Johnson

Brain and Mind Institute Researchers' Publications

Neuroimaging research has demonstrated that the posterior cingulate cortex (PCC) is functionally compromised in individuals diagnosed with amnestic mild cognitive impairment (MCI), a major risk factor for the development of Alzheimer's disease (AD). In functional MRI studies with healthy participants, this same region is active during self-appraisal (requiring retrieval of semantic knowledge about the self) as well as episodic recognition of previously learned information. Administering both types of tasks to people with MCI may reveal important information on the role of the PCC in recollection. This study investigated fMRI activation in the PCC in individuals with MCI and matched controls …


Reduced Hippocampal Activation During Episodic Encoding In Middle-Aged Individuals At Genetic Risk Of Alzheimer's Disease: A Cross-Sectional Study, Mehul A. Trivedi, Taylor W. Schmitz, Michele L. Ries, Britta M. Torgerson, Mark A. Sager, Bruce P. Hermann, Sanjay Asthana, Sterling C. Johnson Jan 2006

Reduced Hippocampal Activation During Episodic Encoding In Middle-Aged Individuals At Genetic Risk Of Alzheimer's Disease: A Cross-Sectional Study, Mehul A. Trivedi, Taylor W. Schmitz, Michele L. Ries, Britta M. Torgerson, Mark A. Sager, Bruce P. Hermann, Sanjay Asthana, Sterling C. Johnson

Brain and Mind Institute Researchers' Publications

Background: The presence of the apolipoprotein E (APOE) ε4 allele is a major risk factor for the development of Alzheimer's disease (AD), and has been associated with metabolic brain changes several years before the onset of typical AD symptoms. Functional MRI (fMRI) is a brain imaging technique that has been used to demonstrate hippocampal activation during measurement of episodic encoding, but the effect of the ε4 allelle on hippocampal activation has not been firmly established. Methods: The present study examined the effects of APOE genotype on brain activation patterns in the media[ temporal lobe (MTL) during an episodic encoding task …


Evaluación De Anticuerpos Contra El Virus De La Diarrea Viral Bovina De Un Hato En Proceso De Erradicación De La Enfermedad., Zuniga Alfonso H., Hermelinda G. Rivera, Mariluz Araínga, Alberto Manchego S. Jan 2006

Evaluación De Anticuerpos Contra El Virus De La Diarrea Viral Bovina De Un Hato En Proceso De Erradicación De La Enfermedad., Zuniga Alfonso H., Hermelinda G. Rivera, Mariluz Araínga, Alberto Manchego S.

Journal Articles: Pharmacology & Experimental Neuroscience

Antibodies against viral bovine diarrhea virus (BVDV) and of BVDV antigen in serum samples Were evaluated from cattle aged 10 to 23 months (n = 148) from a dairy herd disease eradication where the has-been carrying out since 2002. The herd is located in Santa Rita, Arequipa, Peru, and samples were collected twice on a 30-day interval. Antibodies against BVDV and BVDV antigen were analyzed by viral neutralization and capture ELISA tests respectively. Neutralising antibodies against BVDV were detected in 6.8% (10/148) of animals, and most reactors were 19 to 23 months of age. The antibody titer ranged from 8 …


Temporal Processing In The Exponential Integrate-And-Fire Model Is Nonlinear, Joanna R. Wares, Todd W. Troyer Jan 2006

Temporal Processing In The Exponential Integrate-And-Fire Model Is Nonlinear, Joanna R. Wares, Todd W. Troyer

Department of Math & Statistics Faculty Publications

The exponential integrate-and-fire (EIF) model was introduced by Fourcaud-Trocme et al. (2003) as an extension of the standard leaky integrate-and-fire model (LIF). Here, the nonlinearity in the EIF model’s temporal response to square-wave inputs is investigated. Comparing the time course of onset and offset responses revealed that offset responses have a steeper initial slope, but a slower approach to equilibrium. A linear systems analysis performed for these square-wave inputs indicates that at frequencies above ~40 Hz, gain was slightly smaller for square-wave inputs, but phase did not change significantly relative to simulations in which the corresponding sinusoids were presented in …