Medicine Marrow Pg No 567-576 (Neurology)
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Questions and Answers

Which area of the brain is primarily associated with the retrieval of episodic memory?

  • Association areas
  • Prefrontal cortex
  • Neocortex
  • Hippocampus (correct)
  • Long-term memory storage is associated with the neocortex.

    True

    What is the term for the process of transforming information into a form that can be stored in memory?

    Encoding

    The retrieval of memories from the recent past might engage the _______ cortex.

    <p>Prefrontal</p> Signup and view all the answers

    Match the types of memory with their descriptions:

    <p>Episodic = Based on time and context Semantic = Based on facts Procedural = Skills and tasks Priming = Exposure influences response</p> Signup and view all the answers

    Which part of the brain is known as the gateway of memory?

    <p>Entorhinal cortex</p> Signup and view all the answers

    The Mammillary body is part of the Papez circuit and is associated with Wernicke Korsakoff syndromes.

    <p>True</p> Signup and view all the answers

    What is the primary function of the Papez circuit?

    <p>Memory processing</p> Signup and view all the answers

    The ------- gyrus is involved in emotional regulation and is a component of the Papez circuit.

    <p>cingulate</p> Signup and view all the answers

    Match the following parts of the Papez circuit with their roles:

    <p>Hippocampus/Subiculum = Memory formation Fornix = Connects hippocampus to mammillary body Thalamus = Relay station for signals Parahippocampal gyrus = Recall and recognition of memories</p> Signup and view all the answers

    Which type of aphasia is characterized by impaired comprehension, repetition, and fluency?

    <p>Broca's aphasia</p> Signup and view all the answers

    Motor aphasia is associated with fluent speech.

    <p>False</p> Signup and view all the answers

    What defines jargon speech in sensory aphasia?

    <p>Replacing words with similar sounds.</p> Signup and view all the answers

    Pure alexia is caused by a lesion in the __________ gyrus.

    <p>fusiform</p> Signup and view all the answers

    Match the type of aphasia with its characteristic:

    <p>Transcortical motor aphasia = Preserved comprehension, impaired repetition Broca's aphasia = Impaired comprehension, repetition, and fluency Isolation aphasia = Preserved comprehension, impaired repetition Global aphasia = Impaired comprehension, repetition, and fluency</p> Signup and view all the answers

    Which type of aphasia is characterized by preserved comprehension but difficulty in finding the right words?

    <p>Anomic aphasia</p> Signup and view all the answers

    Patients with conduction aphasia have intact repetition skills.

    <p>False</p> Signup and view all the answers

    Which area of the brain is primarily associated with procedural memory?

    <p>Cerebellum</p> Signup and view all the answers

    What type of dysarthria results from damage to lower motor neurons in the brainstem nuclei?

    <p>Flaccid dysarthria</p> Signup and view all the answers

    Priming is associated with the amygdala.

    <p>False</p> Signup and view all the answers

    What type of memory is primarily involved when animals associate fear with their environment?

    <p>Associative (Conditional) memory</p> Signup and view all the answers

    In patients with Wernicke's aphasia, comprehension is usually ________ and reading/writing may contain errors.

    <p>impaired</p> Signup and view all the answers

    The gateway of long-term memory is the _______ cortex.

    <p>entorhinal</p> Signup and view all the answers

    Match the type of aphasia with its characteristic:

    <p>Wernicke's Aphasia = Impaired comprehension, poor preservation, reading and writing errors Anomic Aphasia = Preserved comprehension, difficulty in word retrieval Transcortical Sensory Aphasia = Impaired comprehension and repetition Conduction Aphasia = Inability to repeat accurately despite preserved comprehension</p> Signup and view all the answers

    Match the areas of the brain with their associated types of memory:

    <p>Frontal = All types of memory Parietal = Semantic memory Temporal = Episodic semantic memory Amygdala = Conditional memory</p> Signup and view all the answers

    What is the most common cause of young onset dementia?

    <p>Frontotemporal Dementia (Pick's disease)</p> Signup and view all the answers

    Vitamin B₁₂ deficiency can be a reversible cause of dementia.

    <p>True</p> Signup and view all the answers

    What is the most important risk factor for Alzheimer's disease?

    <p>Age over 85 years old</p> Signup and view all the answers

    The __________ of entorhinal cortex is specific to Alzheimer's Disease.

    <p>atrophy</p> Signup and view all the answers

    Match the following conditions with their classification:

    <p>Chronic meningitis = Infections Hypothyroidism = Endocrine Anemia = Anemia and Autoimmune Prion disease = Rapidly Progressive Young Onset Dementia</p> Signup and view all the answers

    What abnormal accumulation is associated with amyloid plaques in Alzheimer's disease?

    <p>Aβ42 fragments</p> Signup and view all the answers

    The deposition of Aβ in blood vessels is associated with cerebral amyloid angiopathy.

    <p>True</p> Signup and view all the answers

    What enzyme is responsible for breaking down insulin in the context of hyperinsulinemia?

    <p>Insulin-degrading enzyme (IDE)</p> Signup and view all the answers

    Accumulation of _______ proteins leads to neurofibrillary tangles inside neurons.

    <p>hyperphosphorylated tau</p> Signup and view all the answers

    Match the diseases with their associated features:

    <p>Alzheimer's Disease = Atrophy of the median temporal lobe Cerebral Amyloid Angiopathy = Microhemorrhages in the brain Diabetes = Hyperinsulinemia Neurofibrillary Tangles = Inside neurons</p> Signup and view all the answers

    Which of the following is considered the most common cause of dementia?

    <p>Alzheimer's disease</p> Signup and view all the answers

    Cortical dementia is primarily associated with subcortical brain areas.

    <p>False</p> Signup and view all the answers

    Name one cognitive domain affected by dementia.

    <p>Episodic memory</p> Signup and view all the answers

    The area involved in language processing in dementia is the _______ frontal gyrus.

    <p>inferior</p> Signup and view all the answers

    Match the following types of dementia with their characteristics:

    <p>Alzheimer's disease = Most common cause of dementia Diffuse Lewy body dementia = Cortical dementia Normal pressure hydrocephalus = Subcortical dementia Binswanger disease = Vascular dementia</p> Signup and view all the answers

    Which of the following is the most important risk factor for sporadic Alzheimer's Disease in the elderly?

    <p>Apo e4</p> Signup and view all the answers

    Low IQ is a known risk factor for developing Alzheimer's Disease.

    <p>False</p> Signup and view all the answers

    What clinical stage of dementia involves behavioral abnormalities and personality changes?

    <p>Stage IV</p> Signup and view all the answers

    The gene associated with familial Alzheimer's Disease found on chromosome 14 is known as _____ - 1.

    <p>Presenilin</p> Signup and view all the answers

    Match the risk factors or characteristics with the associated categories:

    <p>Apo e4 = Chronic condition linked to late-onset dementia Metabolic syndrome = Risk factor for dementia H/o stroke = Potential contributor to dementia risk F &gt; m = Gender disparity in incidence</p> Signup and view all the answers

    Which treatment is considered the first-line option for Alzheimer's disease?

    <p>Donepezil</p> Signup and view all the answers

    Cholinesterase inhibitors include Rivastigmine and Galantamine, but not Memantine.

    <p>True</p> Signup and view all the answers

    What imaging technique detects hypometabolism in Alzheimer's disease?

    <p>PET scan</p> Signup and view all the answers

    The levels of hyperphosphorylated tau are analyzed in _____ analysis for neurological conditions.

    <p>CSF</p> Signup and view all the answers

    Match the following treatments with their categories:

    <p>Donepezil = Cholinesterase inhibitor Memantine = NMDA antagonist Aducanumab = Monoclonal antibody Tacrine = Obsolete therapy</p> Signup and view all the answers

    Study Notes

    Papez Circuit

    • The Papez circuit, also known as the mammillo-thalamic circuit, is a neural pathway involved in memory and emotion.
    • It is crucial for the formation and retrieval of memories.
    • The pathway starts at the hippocampus and subiculum, travels through the fornix and mammillary bodies, then continues through the mammillo-thalamic tract to the thalamus.
    • From there, it progresses to the internal capsule, cingulate gyrus, parahippocampal gyrus, and finally ends at the entorhinal cortex, known as the "gateway of memory.”

    Memory

    • Memory encompasses three crucial processes: encoding, consolidation, and retrieval.
    • Encoding is the initial stage of memory formation, where information is registered and processed.
    • Consolidation involves the strengthening and stabilization of the encoded memories, transforming them from temporary to more permanent forms.
    • Retrieval is the process of accessing and recalling stored memories when needed.

    Classification of Memory

    • Memories can be classified based on their duration or mode of retrieval.
    • The traditional classification categorizes memories as immediate, short-term/recent, or long-term, each associated with different brain areas.

    Immediate memory

    • No permanent storage, usually within 1 minute
    • Relies largely on the prefrontal cortex.

    Short-term/Recent memory

    • Dependent on the hippocampus
    • Retained for a few minutes to several hours
    • Typically requires the prefrontal cortex for recall.

    Long-term memory

    • Stored more permanently in the neocortex.
    • Retrieving long-term memories also involve the prefrontal cortex.

    Mode of Retrieval

    • Current classifications focus on the mode of retrieval, dividing memories into explicit (declarative) and implicit (non-declarative) categories.

    Explicit memory

    • Involves conscious recall of memories.
    • Includes episodic and semantic memory.
    Episodic Memory
    • Encoded with time & context
    • Autobiographical in nature
    • Primarily located in the hippocampus
    • Often affected early in Alzheimer's disease
    Semantic Memory
    • Based on facts and general knowledge
    • Primarily located in association areas of the brain.
    • Usually remains intact even in later stages of Alzheimer's disease.

    Implicit memory

    • Non-conscious memories that influence behavior or performance.
    • Includes procedural, priming, associative, and non-associative memories.
    Procedural Memory
    • Involves skills and habits
    • Affected in Huntington's disease
    Priming Memory
    • Refers to the increased likelihood of remembering something due to prior exposure
    • Occurs when exposed to specific information.
    Associative Memory
    • Forms connections between events or stimuli
    • Leads to conditioned learning
    • Rarely seen in humans, but common in animals.
    Non-associative Memory
    • Involves basic forms of learning such as habituation and sensitization
    • Relates to changes in reflexes.

    Anatomy of Memory

    Cortex

    • Different regions of the cortex are associated with specific memory types.
    • The prefrontal cortex plays a role in all types of memory, including working memory.
    • The parietal association area (Parieto-occipital) is involved in semantic memory.
    • The temporal lobe, especially the hippocampus, is central to episodic memory and semantic memory.
    • The occipital lobe also contributes to semantic memory.

    Subcortex

    • Specific subcortical structures are also implicated in memory functions.
    • The amygdala is associated with associative memory and emotional responses attached to memories.
    • The cerebellum is involved in procedural memory, particularly motor skills.
    • The entorhinal cortex acts as a "gateway" to long-term memory.
    • The basal ganglia, part of the subcortical structures, influences procedural memory, impacting motor learning and habits.

    Dementia

    • A major cognitive impairment characterized by a significant decline in at least two cognitive domains.
    • The decline impacts everyday activities and independence.

    Cognitive Domains Affected by Dementia

    • Episodic memory: impairment in the ability to remember past events
    • Language: difficulty with speech, comprehension, and naming
    • Complex attention: challenges with focusing, shifting attention, and multitasking
    • Executive function: problems with planning, decision-making, and problem-solving
    • Social cognition: difficulties with understanding social cues and interacting appropriately
    • Visuospatial function: challenges with navigating, drawing, or copying

    Causes of Dementia

    • Alzheimer's disease accounts for the majority of cases
    • Diffuse Lewy body (DLB) dementia is another common cause
    • Vascular dementia, including post-stroke dementia and white matter dementia (Binswanger disease), is a significant cause
    • Normal pressure hydrocephalus (NPH) is relatively uncommon but can be a reversible cause of dementia.

    Location of Brain Damage

    • Dementia can be classified based on the affected brain areas into cortical dementia and subcortical dementia:
    Cortical Dementia
    • Diffuse Lewy body (DLB) dementia
    • Progressive supranuclear palsy
    • Binswanger disease
    Subcortical Dementia
    • NPH

    Genetic Basis of Dementia

    • Strong correlation with a family history of dementia.
    • Genes linked to dementia include:
      • Presenilin-1 (chromosome 14): The most common defect in familial Alzheimer's disease
      • Presenilin-2 (chromosome 1):
      • ApoE4 (chromosome 19): A significant risk factor for sporadic Alzheimer's disease, especially in late-onset cases.

    Risk Factors for Dementia

    • Age: The most critical risk factor, with the risk significantly increasing after 85 years.
    • Family history of dementia
    • Head trauma or concussions
    • Stroke
    • Metabolic syndrome
    • Hypertension
    • Diabetes

    Factors NOT associated with increased dementia risk

    • Low IQ
    • Smoking
    • NSAIDS

    Clinical Stages of Dementia

    • Dementia progresses through distinct stages, impacting different cognitive areas:

    Stage I: Korsakoff Amnestic Stage

    • Characterized by episodic memory loss, particularly difficulty consolidating new memories.
    • Key brain area affected: hippocampus.

    Stage II: Stage of Anomia

    • Involves naming and comprehension difficulties
    • Associated with challenges in language processing.

    Stage III: Visuospatial Disorientation

    • Marked by difficulties with orientation in space and problems with visual perception tasks
    • Linked to damage in the angular gyrus.

    Stage IV: Behavioral Abnormalities and Personality Changes

    • Significant impact on personality and behavior
    • Often involves emotional changes, agitation, and behavioral disturbances
    • Primarily related to prefrontal cortex dysfunction.

    Neurological Assessment of Aphasia and Dysarthria

    Aphasia

    Types of Aphasia
    • Conduction aphasia: Lesion in the arcuate fasciculus, resulting in difficulty repeating words and sentences.
    • Transcortical Sensory Aphasia: D/t infarct, causing issues with comprehension and repetition.
    • Wernicke's aphasia: D/t infarct, leading to impaired comprehension. Reading and writing are also impacted.
    Categories of Aphasia Based on Language Function
    • Preserved Comprehension:
      • Anomic aphasia: Lesion in the angular gyrus, causing difficulty finding the right word.
    • Impaired Comprehension:
      • Conduction aphasia: Lesion in the arcuate fasciculus, resulting in inability to repeat accurately.
      • Transcortical sensory aphasia: D/t infarct, causes impaired comprehension and repetition.
      • Wernicke's aphasia: D/t infarct, leads to impaired comprehension, reading and writing issues.

    Dysarthria

    Types of Dysarthria
    • Cortical Dysarthria: Related to Broca's aphasia, affecting motor speech control.
      • Pseudo bulbar (Spastic dysarthria): D/t damage to corticobulbar fibres impacting the anterior horn cells.
    • Bulbar Dysarthria: Occurs due to damage to lower motor neurons in the brainstem nuclei.
      • Flaccid Dysarthria: Damage to lower motor neurons, resulting in weak speech muscles.

    Investigations for Dementia

    • The diagnosis of dementia relies on clinical assessment, neuropsychological testing, and imaging techniques.

    EEG

    • Can show general slowing of brain activity, but usually not specific to dementia.

    CSF Analysis

    • May reveal elevated levels of amyloid beta (Aβ42) or hyperphosphorylated tau proteins, suggesting Alzheimer's disease.

    PET Scan

    • Utilizes radioactive tracers to visualize brain activity and metabolic function.
    • In dementia, PET scans can show hypometabolism in affected brain regions.
    • Specialized amyloid PET scans can detect amyloid plaques.

    MRI

    • Can show structural changes in the brain, such as atrophy, particularly in the hippocampus and temporal lobe.

    Treatment of Dementia

    • Currently, no cure exists for dementia, but medications can help manage symptoms and slow the progression of the disease.

    Medications

    • Cholinesterase inhibitors (DOC):
      • Donepezil
      • Rivastigmine
      • Galantamine
    • NMDA antagonist: memantine
    • Monoclonal antibody against Aβ42: Aducanumab

    Obsolete Medications

    • Tacrine (due to hepatotoxicity)

    PIB PET Scans

    • Can be used to detect amyloid plaques, providing further evidence for Alzheimer's disease.
    • Images of PIB PET scans show higher amyloid deposition in individuals with Alzheimer's disease, indicating increased plaque formation.

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    Explore the Papez circuit, a neural pathway critical for memory and emotion. This quiz covers the components of memory, including encoding, consolidation, and retrieval processes. Test your knowledge on how these elements work together in the brain.

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