A Review of the Role of Estrogens in Olfaction, Sleep and Glymphatic Functionality in Relation to Sex Disparity in Alzheimer's Disease.

Several risk factors contribute to the development of Alzheimer's disease (AD), including genetics, metabolic health, cardiovascular history, and diet. It has been observed that women appear to face a higher risk of developing AD. Among the various hypotheses surrounding the gender disparity in AD, one pertains to the potential neuroprotective properties of estrogen.

Olfactory-trigeminal integration in the primary olfactory cortex.

Humans naturally integrate signals from the olfactory and intranasal trigeminal systems. A tight interplay has been demonstrated between these two systems, and yet the neural circuitry mediating olfactory-trigeminal (OT) integration remains poorly understood. Using functional magnetic resonance imaging (fMRI), combined with psychophysics, this study investigated the neural mechanisms underlying OT integration.

Single-Center In-Hospital and Outpatient Opioid Use for Lower Extremity Arterial Disease.

Introduction: The pain associated with lower extremity arterial disease is difficult to treat, even with lower extremity revascularization. We sought to evaluate in-hospital and post-operative opioid usage in patients with different disease severities and treatments for lower extremity vascular disease.

Methods: A retrospective review was performed for all hospital encounters for patients with an International Classification of Diseases (ICD) code consistent with lower extremity arterial disease admitted to a single center between January 2018 and March 2023.

Neural correlates of chocolate brand preference: A functional MRI study.

Background And Purpose: Preferences can be developed for, or against, specific brands and services. Using two functional magnetic resonance imaging (fMRI) experiments, this study investigated two dissociable aspects of reward processing, craving and liking, in chocolate lovers. The goal was to further delineate the neural basis supporting branding effects using familiar chocolate (FC) and unfamiliar chocolate (UC) brand images.

A review and perspective on the neural basis of radiological expertise.

Radiological expertise requires tremendous time, effort, and training. While there has been a myriad of studies focusing on radiological expertise and error, the precise underlying neural mechanism still remains largely unexplored. In this article, we review potential neural mechanisms, namely, the fusiform face area, working memory, and predictive coding and propose experiments to test the predictive coding framework.

Monorhinal and Birhinal Odor Processing in Humans: an fMRI investigation.

The olfactory nerve, also known as cranial nerve I, is known to have exclusive ipsilateral projections to primary olfactory cortical structures. It is still unclear whether these projections also correspond to functional pathways of odor processing. In an olfactory functional magnetic resonance imaging (fMRI) study of twenty young healthy subjects with a normal sense of smell, we tested whether nostril specific stimulation with phenyl ethyl alcohol (PEA), a pure olfactory stimulant, asymmetrically activates primary or secondary olfactory-related brain structures such as primary olfactory cortex, entorhinal cortex, and orbitofrontal cortex.

Evidence from an fMRI study that dessert-flavored e-cigarettes engage taste-related, but not smoking-related, brain circuitry for female daily smokers.

Regulations limiting the sale of flavored e-cigarette products are controversial for their potential to interfere with e-cigarette use as a cessation aid in addition to curbing youth use. Limited research suggests that flavor might enhance the addictive potential of e-cigarettes; however, the acute effects of flavored aerosols on brain function among humans have not been assessed. The present study aimed to isolate and compare the neural substrates of flavored and unflavored e-cigarette aerosols on brain function among nine female daily smokers.

Olfactory Costimulation Influences Intranasal Somatosensory Perception.

Olfactory sensitivity is influenced by intranasal trigeminal sensation. For instance, sniffing is central to how humans and animals perceive odorants. Here, we investigated the influence of olfactory costimulation on the perception of intranasal somatosensory stimulation.

An Electronic Aerosol Delivery System for Functional Magnetic Resonance Imaging.

Background: Public health concerns over the addictive potential of electronic cigarettes (e-cigs) have heightened in recent years. Brain function during e-cig use could provide an objective measure of the addictive potential of new vaping products to facilitate research; however, there are limited methods for delivering e-cig aerosols during functional magnetic resonance imaging (fMRI). The current study describes the development and feasibility testing of a prototype to deliver up to four different e-cig aerosols during fMRI.

Functional Connectivity between the Resting-State Olfactory Network and the Hippocampus in Alzheimer's Disease.

Olfactory impairment is associated with prodromal Alzheimer's disease (AD) and is a risk factor for the development of dementia. AD pathology is known to disrupt brain regions instrumental in olfactory information processing, such as the primary olfactory cortex (POC), the hippocampus, and other temporal lobe structures. This selective vulnerability suggests that the functional connectivity (FC) between the olfactory network (ON), consisting of the POC, insula and orbital frontal cortex (OFC) (Tobia et al.

Disruptions of the olfactory and default mode networks in Alzheimer's disease.

Introduction: Olfactory deficits are prevalent in early Alzheimer's disease (AD) and are predictive of progressive memory loss and dementia. However, direct neural evidence to relate AD neurodegeneration to deficits in olfaction and memory is limited.

Methods: We combined the University of Pennsylvania Smell Identification Test (UPSIT) with olfactory functional magnetic resonance imaging (fMRI) to investigate links between neurodegeneration, the olfactory network (ON) and the default mode network (DMN) in AD.

Different patterns of age-related central olfactory decline in men and women as quantified by olfactory fMRI.

Age-related olfactory decline, or presbyosmia, is a prevalent condition with potentially devastating consequences on both quality of life and safety. Despite clear evidence for this decline, it is unknown whether presbyosmia is sex-dependent and also whether it is due to central or peripheral olfactory system deterioration. Therefore, the goals of this study were to investigate the neurofunctional substrate of olfactory decline and examine its relationship to age and sex in thirty-seven (18 women, 19 men) healthy older participants using olfactory functional MRI (fMRI).

Age-related resting-state functional connectivity in the olfactory and trigeminal networks.

Brain networks for intranasal chemosensation have been shown to be intrinsically organized in humans . However, little is known about how changes in the intrinsic functional connectivity (FC) in chemosensory networks are related to aging. We, therefore, investigated the impact of age on resting-state FC in the olfactory and trigeminal networks (ON and TN) by combining two freely available resting-state fMRI data sets (obtained from the NITRC.

Lexical-Semantic Search Under Different Covert Verbal Fluency Tasks: An fMRI Study.

Verbal fluency is a measure of cognitive flexibility and word search strategies that is widely used to characterize impaired cognitive function. Despite the wealth of research on identifying and characterizing distinct aspects of verbal fluency, the anatomic and functional substrates of retrieval-related search and post-retrieval control processes still have not been fully elucidated. Twenty-one native English-speaking, healthy, right-handed, adult volunteers (mean age = 31 years; range = 21-45 years; 9 F) took part in a block-design functional Magnetic Resonance Imaging (fMRI) study of free recall, covert word generation tasks when guided by phonemic (P), semantic-category (C), and context-based fill-in-the-blank sentence completion (S) cues.

Central Olfactory Dysfunction in Alzheimer's Disease and Mild Cognitive Impairment: A Functional MRI Study.

Background: Olfactory deficits are present in early Alzheimer's disease (AD) and mild cognitively impaired (MCI) patients. However, whether these deficits are due to dysfunction of the central or peripheral olfactory nervous system remains uncertain. This question is fundamentally important for developing imaging biomarkers for AD using olfactory testing.

Muscle oxygenation during dynamic plantar flexion exercise: combining BOLD MRI with traditional physiological measurements.

Blood-oxygen-level-dependent magnetic resonance imaging (BOLD MRI) has the potential to quantify skeletal muscle oxygenation with high temporal and high spatial resolution. The purpose of this study was to characterize skeletal muscle BOLD responses during steady-state plantar flexion exercise (i.e.

Default mode network deactivation during odor-visual association.

Default mode network (DMN) deactivation has been shown to be functionally relevant for goal-directed cognition. In this study, the DMN's role during olfactory processing was investigated using two complementary functional magnetic resonance imaging (fMRI) paradigms with identical timing, visual-cue stimulation, and response monitoring protocols. Twenty-nine healthy, non-smoking, right-handed adults (mean age = 26 ± 4 years, 16 females) completed an odor-visual association fMRI paradigm that had two alternating odor + visual and visual-only trial conditions.

Dynamic characteristics of T2*-weighted signal in calf muscles of peripheral artery disease during low-intensity exercise.

Purpose: To evaluate the dynamic characteristics of T2* -weighted signal change in exercising skeletal muscle of healthy subjects and peripheral artery disease (PAD) patients under a low-intensity exercise paradigm.

Materials And Methods: Nine PAD patients and nine age- and sex-matched healthy volunteers underwent a low-intensity exercise paradigm while magnetic resonance imaging (MRI) (3.0T) was obtained.

Default mode network differences between rigidity- and tremor-predominant Parkinson's disease.

Background: Parkinson's disease (PD) traditionally is characterized by tremor, rigidity, and bradykinesia, although cognitive impairment also is a common symptom. The clinical presentation of PD is heterogeneous and associated with different risk factors for developing cognitive impairment. PD patients with primary akinetic/rigidity (PDAR) are more likely to develop cognitive deficits compared to those with tremor-predominant symptoms (PDT).

Intrinsic intranasal chemosensory brain networks shown by resting-state functional MRI.

The human brain is organized into functional networks for sensory-motor and cognitive processing. Intrinsic networks are detectable in the absence of stimulation or task demands, whereas extrinsic networks are detectable when stimulated by sensory or cognitive demands. Intranasal chemosensory processing relies on two dissociable networks for processing incoming trigeminal and olfactory stimulation, but it is not known whether these networks are intrinsically organized.

Rapidly acquired multisensory association in the olfactory cortex.

Background: The formation of an odor percept in humans is strongly associated with visual information. However, much less is known about the roles of learning and memory in shaping the multisensory nature of odor representations in the brain.

Method: The dynamics of odor and visual association in olfaction was investigated using three functional magnetic resonance imaging (fMRI) paradigms.

Olfactory cortex degeneration in Alzheimer's disease and mild cognitive impairment.

Background: Olfactory deficits are prevalent in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). These symptoms precede clinical onset of cognitive and memory deficits and coincide with AD pathology preferentially in the central olfactory structures, suggesting a potential biomarker for AD early detection and progression.

Objective: Therefore, we tested the hypothesis that structural degeneration of the primary olfactory cortex (POC) could be detected in AD as well as in MCI patients and would be correlated with olfactory functional magnetic resonance imaging (fMRI) alterations, reflecting loss of olfactory cortex activity.

Networks involved in olfaction and their dynamics using independent component analysis and unified structural equation modeling.

The study of human olfaction is complicated by the myriad of processing demands in conscious perceptual and emotional experiences of odors. Combining functional magnetic resonance imaging with convergent multivariate network analyses, we examined the spatiotemporal behavior of olfactory-generated blood-oxygenated-level-dependent signal in healthy adults. The experimental functional magnetic resonance imaging (fMRI) paradigm was found to offset the limitations of olfactory habituation effects and permitted the identification of five functional networks.

BOLD fMRI in infants under sedation: Comparing the impact of pentobarbital and propofol on auditory and language activation.

Purpose: To elucidate differences in the disruption of language network function, as measured by blood oxygenation level-dependent (BOLD) contrast functional MRI (fMRI), attributable to two common sedative agents administered to infants under clinical imaging protocols.

Materials And Methods: The sedatives pentobarbital (Nembutal) and Propofol, administered clinically to infants at 1 year of age, were compared with respect to BOLD activation profiles in response to passive story-listening stimulation. An intermittent event-related imaging protocol was used with which the temporal evolution of language processing resulting from this stimulation was explored.