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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.


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, …


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. …


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 …


Visual Adaptation To Masculine And Feminine Faces Influences Generalized Preferences And Perceptions Of Trustworthiness, Gavin Buckingham, Lisa Debruine, Anthony Little, Lisa Welling, Claire Conway, Bernard Tiddeman, Benedict Jones Aug 2006

Visual Adaptation To Masculine And Feminine Faces Influences Generalized Preferences And Perceptions Of Trustworthiness, Gavin Buckingham, Lisa Debruine, Anthony Little, Lisa Welling, Claire Conway, Bernard Tiddeman, Benedict Jones

Gavin Buckingham

Although previous studies of individual differences in preferences for masculinity in male faces have typically emphasized the importance of factors such as changes in levels of sex hormones during the menstrual cycle, other research has demonstrated that recent visual experience with faces also influences preferences for sexual dimorphism in faces. Adaptation to either masculine or feminine faces increases preferences for novel faces that are similar to those that were recently seen. Here, we replicate this effect and demonstrate that adaptation to masculine or feminine faces also influences the extent to which masculine faces are perceived as trustworthy. These adaptation effects …


Age And Physical Activity Influences On Action Monitoring During Task Switching, Jason R. Themanson, Charles H. Hillman, John J. Curtin Aug 2006

Age And Physical Activity Influences On Action Monitoring During Task Switching, Jason R. Themanson, Charles H. Hillman, John J. Curtin

Jason R. Themanson, Ph.D

Behavioral and neuroelectric indices of action monitoring were compared for 53 high and low physically active older (60–71 years) and younger (18–21 years) adults during a task-switching paradigm in which they performed a task repeatedly or switched between two different tasks. The error-related negativity (ERN) of a response-locked event-related brain potential (ERP) and behavioral measures of response speed and accuracy were measured during the heterogeneous condition (switching randomly between two tasks) of the switch task. Results indicated that older adults exhibited a greater relative slowing in RT during heterogeneous blocks and smaller ERN amplitude compared to younger adults. Additionally, physical …


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.


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 …


Reflections On… Phase Shifting Under Different Visual Conditions, Gavin Buckingham, David Carey, Arash Sahraie Dec 2005

Reflections On… Phase Shifting Under Different Visual Conditions, Gavin Buckingham, David Carey, Arash Sahraie

Gavin Buckingham

When two limbs are moved out of time (i.e. opposing muscle activation at each limb) in rhythmic oscillatory movements, there is a tendency at high frequencies for the movements to synchronise in the temporal domain, resulting in bilateral homologous muscle activation known as a ‘phase shift’ (Kelso, 1984). In an effort to determine the degree with which perception influences this phase shifting behaviour (Mechsner et al., 2001), a mirror can be placed between the hands of participants, parallel to their mid-saggital plane such that the reflected hand appeared in the place of the occluded hand. This paradigm can be used …


Visual Adaptation To Masculine And Feminine Faces Influences Generalized Preferences And Perceptions Of Trustworthiness, Gavin Buckingham, L. Debruine, A. Little, L. Welling, C. Conway, B. Tiddeman, B. Jones Dec 2005

Visual Adaptation To Masculine And Feminine Faces Influences Generalized Preferences And Perceptions Of Trustworthiness, Gavin Buckingham, L. Debruine, A. Little, L. Welling, C. Conway, B. Tiddeman, B. Jones

Gavin Buckingham

We compared the effects of adaptation to faces varying in sexual dimorphism of shape on perceptions of the trustworthiness and attractiveness of masculine faces.


Cardiorespiratory Fitness And Acute Aerobic Exercise Effects On Neuroelectric And Behavioral Measures Of Action Monitoring, Jason R. Themanson, Charles H. Hillman Dec 2005

Cardiorespiratory Fitness And Acute Aerobic Exercise Effects On Neuroelectric And Behavioral Measures Of Action Monitoring, Jason R. Themanson, Charles H. Hillman

Jason R. Themanson, Ph.D

Cardiorespiratory fitness and acute aerobic exercise effects on cognitive function were assessed for 28 higher- and lower-fit adults during a flanker task by comparing behavioral and neuroelectric indices of action monitoring. The error-related negativity, error positivity, and N2 components, as well as behavioral measures of response speed, accuracy, and post-error slowing were measured following a 30-minute acute bout of treadmill exercise or following 30-minutes of rest. A graded maximal exercise test was used to measure cardiorespiratory fitness by assessing maximal oxygen uptake. Results indicated that higher-fit adults exhibited reduced error-related negativity amplitude, increased error positivity amplitude, and increased post-error response …