Medicine and Health Sciences Commons^™

Gender- And Region-Specific Changes In Estrogen Signaling In Aging Rat Brain Mitochondria, Christopher M. Evola, Tanner L. Hudson, Luping Huang, Adrian M. Corbett, Debra A. Mayes

Neuroscience, Cell Biology & Physiology Faculty Publications

Recently epidemiological studies suggest females lose neuroprotection from neurodegenerative diseases as they go through menopause. It has been hypothesized that this neuroprotection is hormone‐dependent. The current study characterized cell signaling molecules downstream of estrogen receptor beta that are known to play a role in memory, PKC, ERK, and connexin‐43, in regions of the brain associated with memory decline in an attempt to elucidate significant changes that occur post‐estrus. Total whole cell lysates were compared to isolated mitochondrial protein because mitochondrial function is known to be altered during aging. As hypothesized, protein concentrations differed depending on age, gender, and brain region. …

Neuroimaging Biomarkers Of Mtor Inhibition On Vascular And Metabolic Functions In Aging Brain And Alzheimer’S Disease, Jennifer Lee, Lucille M. Yanckello, David Ma, Jared D. Hoffman, Ishita Parikh, Scott Thalman, Bjoern Bauer, Anika M. S. Hartz, Fahmeed Hyder, Ai-Ling Lin

Pharmacology and Nutritional Sciences Faculty Publications

The mechanistic target of rapamycin (mTOR) is a nutrient sensor of eukaryotic cells. Inhibition of mechanistic mTOR signaling can increase life and health span in various species via interventions that include rapamycin and caloric restriction (CR). In the central nervous system, mTOR inhibition demonstrates neuroprotective patterns in aging and Alzheimer’s disease (AD) by preserving mitochondrial function and reducing amyloid beta retention. However, the effects of mTOR inhibition for in vivo brain physiology remain largely unknown. Here, we review recent findings of in vivo metabolic and vascular measures using non-invasive, multimodal neuroimaging methods in rodent models for brain aging and AD. …

Longitudinal Alzheimer's Degeneration Reflects The Spatial Topography Of Cholinergic Basal Forebrain Projections, Taylor W. Schmitz, Marieke Mur, Meghmik Aghourian, Marc Andre Bedard, R. Nathan Spreng

Brain and Mind Institute Researchers' Publications

© 2018 The Author(s) The cholinergic neurons of the basal forebrain (BF) provide virtually all of the brain's cortical and amygdalar cholinergic input. They are particularly vulnerable to neuropathology in early Alzheimer's disease (AD) and may trigger the emergence of neuropathology in their cortico-amygdalar projection system through cholinergic denervation and trans-synaptic spreading of misfolded proteins. We examined whether longitudinal degeneration within the BF can explain longitudinal cortico-amygdalar degeneration in older human adults with abnormal cerebrospinal fluid biomarkers of AD neuropathology. We focused on two BF subregions, which are known to innervate cortico-amygdalar regions via two distinct macroscopic cholinergic projections. To …

Assessing Listening With Engaging, Real-World Auditory Signals, Brainscan , Western University, Björn Herrmann, Ingrid Johnsrude 6612111

Project Summaries

Our project will develop and evaluate a novel way (using functional imaging, fMRI, and electrophysiology, EEG) to assess this cognitive impact of hearing loss with engaging, real‐world auditory stimuli. We will try to assess listening effort in more realistic listening situations among healthy listeners, comparing detected effort in degraded and clear acoustic conditions.

Using EEG, we will then develop measures that are sensitive to the cognitive demands imposed by degraded speech, using these features to assess hearing function with engaging narratives in natural listening conditions.

Pet And Mri Measurements Of Neuroinflammation And Brain Plasticity After A Stroke, Brainscan , Western University, Jonathan Thiessen, Shawn Whitehead, Justin Hicks, Matthew Fox

Project Summaries

We are going to assess brain structure and function using magnetic resonance imaging (MRI) and positron emission tomography (PET) to study white matter inflammation and the density of synapses over time, alongside a behavioural assessment of motor and executive function. This kind of comprehensive assessment, especially using PET to measure synaptic density, has not been done before.

Uncovering The Neural Basis Of Cognitive Impairment Following Hearing Loss: An All-Optical Electrophysiology Approach, Brainscan, Western University, Brian Allman, Wataru Inoue

Project Summaries

We have access to state-of-the-art equipment that will enable us to visualize specific neuron types in animal models. This is a new approach that combines several recent advances in the field of 'optogenetics', a technique that uses light to control neurons. This approach will allow us to explore how hearing loss induced by loud noise exposure leads to abnormal neural activity in areas of the brain that control learning, memory and higher cognitive function.

Validating Methods For Using Noninvasive Brain Stimulation To Influence Auditory Perception, Brainscan, Western University, Jessica Grahn, Molly Henry, Blake Butler, Marc Joanisse, Stefan Everling

Project Summaries

We will be exploring the influence of a weak alternating current on neural activity at different frequencies to build a more complete picture of tACS. We will also incorporate EEG measurements to help us predict how the synchronization varies across individuals, to determine when to provide stimulation for each individual. Finally, we will vary the tACS stimulation and use participant behaviour as the measure to understand what stimulation timing produces the largest behavioural changes.

Attention Bias Modification Training As A Potential Preventative Tool, Brainscan, Western University, Elizabeth Hayden, Marc Joanisse, Pan Liu, Koraly Perez-Edgar, Thomas Olino

Project Summaries

We will use eye-tracking techniques to understand more about attentional bias and how it changes through ABM training.

Through neuroimaging, we will look at 'resting state functional connectivity', which is the activity and communication in the brain when a person is not engaging in any activity themselves. There are resting-state patterns of brain activity that have been identified in the brains of youth with depression, anxiety and related disorders, but we do not know if these brain patterns can be used to identify those at risk for these disorders. We also don't know if preventative approaches to depression and anxiety, …

The Effect Of Musical Training On Speech And Sound Perception, Brainscan, Western University, Ingrid Johnsrude, Vanessa Irsik, Stephen Van Hedger

Project Summaries

We are going to carry out such a study, in conjunction with research labs at five other institutions. With six universities involved, we will be able to recruit a sufficiently large number of people in the study and decrease the likelihood of any regional bias influencing the outcomes. We will be trying to validate the following claims:

• that musicians have an improved ability to understand speech in noisy environments
• that the responses of a musician's brainstem to speech sounds is enhanced, and
• that older musicians have reduced symptoms from age-related hearing loss.

Aging Is Associated With An Over-Sensitivity Of Brain Responses To Sounds, Brainscan, Western University, Björn Herrmann, Burkhard Maess, Ingrid S. Johnsrude

Research Summaries

Aging and hearing loss leads to increased neural responses to sounds in the auditory cortex compared to younger people. Enhanced neural activity to sound may be a physiological mechanism underlying the difficulty that older adults have with ignoring irrelevant sound information.