neuroanatomy and neuroimaging: application to alzheimer’s disease diagnosis
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Neuroanatomy and Neuroimaging: Application to Alzheimer’s disease diagnosis. Megha Vasavada. Alzheimer’s disease. Most common form of dementia affecting 5.2 million Americans Symptoms: problems with memory, thinking, and behavior As the disease progresses the symptoms intensify - PowerPoint PPT PresentationTRANSCRIPT
Neuroanatomy and Neuroimaging: Application to Alzheimer’s disease
diagnosisMegha Vasavada
Alzheimer’s disease
Most common form of dementia affecting 5.2 million Americans
Symptoms: problems with memory, thinking, and behavior
As the disease progresses the symptoms intensify› Disorientation› mood and behavior changes› deepening confusion about events, time and place › unfounded suspicions about family, friends and
professional caregivers› more serious memory loss and behavior changes› difficulty speaking, swallowing and walking.
Central Nervous System
Controls both voluntary activities and autonomic functions› Integrates sensory information, emotions,
thoughts, memory, and personality
Frontal Lobe
Temporal Lobe
BrainstemCerebellum
Occipital Lobe
Parietal Lobe
• 'higher' cognitive functions• attention• thought• voluntary movement• decision–making• language.
• recognition• perception (hearing, vision, smell)• understanding language• learning and memory
• perception/ integration of somatosensory information (e.g. touch, pressure, temperature, and pain)• visuospatial processing• spatial attention• spatial mapping• number representation
• maintaining homeostasis by controlling autonomic functions (blood pressure, breathing, digestion, heart rate, perspiration and temperature)•alertness•sleep•balance•startle response
• Vision
• coordination of voluntary movement• motor–learning• balance and posture• reflex memory•timing• sequence learning• integration of sensory information
http://www.g2conline.org/2022
Limbic Lobe
Limbic Lobe
• memory formation and storage• regulating emotion• processing smells
Frontal Lobe
Temporal Lobe
Occipital Lobe
Parietal Lobe
Brainstem
Cerebellum
Limbic Lobe
Magnetic Resonance Imaging
MRI:
• Visualize structural changes
• Track neuronal activation by studying blood flow (functional MRI)
Olfaction and Alzheimer’s
AD patients in the early stage have deficits in detection, recognition, and memory of an odor
AD patients have significantly reduced smell sensitivity
Areas involved in olfactory processing are the first areas affected by the classic pathology (Amyloid Beta plaques (Aβ) and neurofibrillary tangles (NFT))
Alzheimer’s Pathology Amyloid Beta
plaques › accumulation of Aβ in
extracellular space. Neurofibrillary
tangles › hyperphosphorylated
tau accumulation within neurons in the brain
Diagnosis occurs here
Alzheimer’s Pathology
Overview
Basic neuroanatomy› Medial temporal lobe = start of AD
patholgy› Olfactory areas are in the medial temporal
lobe Neuroimaging
› MRI provides a tool to look at the anatomy and activation in humans
Therefore, we will use MRI to study early changes in AD patients.
Hypothesis
Olfactory dysfunction will be present in our two patient groups
The volume of the primary olfactory cortex (POC) and hippocampus will be smaller in the two groups
The fMRI will show decreased activation in the POC and the hippocampus
Overall- fMRI is more sensitive to earlier changes in MCI and AD patients
Subjects
AD, mild cognitively impaired (MCI), and normal controls were enrolled› MCI- considered the transitional stage from
normal to AD (important group to study early diagnosis markers)
27 NC 21 MCI 15 AD
Methods
Smell test› University of Pennsylvania Smell
Identification Test MRI:
› Anatomical scan› fMRI scan with an olfactory task
Smell Test- Results
POC and Hippocampus are smaller in MCI and AD
Hip
pocam
pu
s
PO
C
Activation is drastically decreased in MCI and AD
Hippocampus
POC
CN MCI AD
Conclusion UPSIT scores:
› Smell function is affected in MCI and AD Volume
› hippocampus and POC in MCI and AD Activation
› in MCI and AD patients
Activation changes are more drastic than behavioral or volumetric
changes in the MCI group