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Higher Cognition. James H. Baños, Ph.D. Department of Physical Medicine and Rehabilitation. Overview. General Organization and Recurring Themes A Closer Look at Organization Principles in Action: Domains of Cognition. General Organization. Where to begin?. The “vertically organized” brain.
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Higher Cognition James H. Baños, Ph.D. Department of Physical Medicine and Rehabilitation
Overview • General Organization and Recurring Themes • A Closer Look at Organization • Principles in Action: Domains of Cognition
Where to begin? • The “vertically organized” brain
Where to Begin? • Major Dimensions of Organization: • Left vs. Right • Anterior vs. Posterior • Cortical vs. Subcortical
The Damaged and Undamaged Brain • Recurring Themes: • Neural processing rarely occurs in a simple linear or sequential fashion • Instead, it often occurs in continuous “loops” • Like a water faucet that is always running • Architecture is often hierarchical
The Damaged and Undamaged Brain • Recurring Themes • The nervous system thrives on balance and homeostasis of neural processes within these loops • Damage often upsets balance/homeostasis in a process • A “normal” process runs unchecked or fails to run at all • Like other neurologic symptoms, many neurocognitive symptoms can be thought of in “hyper” and “hypo” terms • Ex: muscle tone, reflexes, basal ganglia
Hemispheric Specialization • Don’t think in terms of hemispheric “dominance”
Left Hemisphere Speech Reading/writing Praxis Verbal memory Processing detail Right Hemisphere Arousal Self-awareness Spatially directed attention Emotion/affect Nonverbal memory Visuospatial processing Processing “gestalt” Nonlanguage sound Music Hemispheric Specialization
Left Hemisphere: “Classic” Clinical Presentation Right hemiparesis Aphasia Apraxia Hemispheric Specialization
Right Hemisphere: “Classic” Clinical Presentation Left hemiparesis Poor arousal Left neglect Unawareness of deficits Flat affect Hemispheric Specialization
Posterior Processing of information about the environment Sensory gating Unimodal and multimodal sensory associations Constructing a unified “representation” of the environment across sensory modalities Anterior vs. Posterior
Anterior vs. Posterior • Anterior • Planning and formulating cognitive and behavioral goals • Acting on hypothetical representations of the environment • Incorporating behavioral relevance, reinforcement value, and emotion into cognition and behavior
Cortical vs. Subcortical • Subcortical structures • Initiation • Cessation • Modulation • Control
Cortical vs. Subcortical • Thalamus • Not just a “sensory relay” • Cortico-thalamo-cortical loops modulate: • Consciousness • Arousal • Vigilance • Foundation for higher attentional processes “Cortical tone”
Cortical vs. Subcortical • Basal ganglia • Initiation • Cessation • Maintenance • Similar role in motor and cognitive function
SMA FEF Putamen Caudate (body) Vl-GPi Cl-SNr Cdm-GPi Vl-SNr VLo VLm VAmc MDpl Cortical vs. Subcortical • Cortical-Basal Ganglionic Loops Motor Oculomotor Cortex Striatum Pallidum s. nigra Thalamus
AC DLPFC LOFC VS dl-Caudate (head) vm-Caudate (head) rl-GPi, VP rd-SNr ldm-GPi vl-SNr mdm-GPi rm-SNr pm-MD VAmc MDmc VApc MDpc Cortical vs. Subcortical Anterior Cingulate Dorsolateral Prefrontal Lateral Orbitofrontal Cortex Striatum Pallidum s. nigra Thalamus
Cortical vs. Subcortical • Basal Ganglia: Motor Symptoms • Hyperkinetic disorders (too much movement) • Slow writhing movements • Quick jerking movements • Repetitive abrupt movements • Hypokinetic disorder (too little movement) • Difficulty initiating motor movement • Motor impersistence • Rigidity • Reduced eyeblink
Cortical vs. Subcortical • Basal Ganglia: Cognitive Symptoms • “hypercognitive” • Perseveration • Intrusion • “Hypocognitive” • Poor cognitive initiation • Poor recall (failure to initiate recall processes) • Loss of cognitive set (cognitive impersistence) • Diminished semantic search effectiveness
Cortical vs. Subcortical • Basal Ganglia: Emotionally Guided Behavior • “hyper” • Obsessive-compulsive behaviors • Addiction, gambling • Mania (in some disorders such as Huntington’s Disease) • Affective Lability • “Hypo” • Avolition • Flat affect
Feedback Plan Cortex Cerebellum “Reality” Effectors Cortical vs. Subcortical • Cerebellum Cerebrocerebellum
Cortical vs. Subcortical • Cerebellar Signs • Motor • Ataxia • Dysmetria • Cognitive • “Cognitive Ataxia” • “Dysmetria of Thought” • Emotionally Guided Behavior • Affective lability • Psychiatric symptoms
Putting it Together… Common View: Cognition Motor/Sensory
Putting it Together… Reality: Emotionally Guided Behavior Cognition Sensorimotor Purposeful Effortful Automatic
Domains of Cognition • Motor and Sensory Aspects of Cognition • Language • Attention • Executive Function
Hierarchical Organization Multimodal Association Cortex Unimodal Association Primary Sensory
Hierarchical Organization Multimodal Association Somatosensory Association Visual Association Auditory Association Primary Somatosensory Primary Visual Primary Auditory
Hierarchical Organization Somatosensory visual auditory
Hierarchical Processing Anterior Posterior Multimodal Association Cortex Unimodal Association Unimodal Association Unimodal Association Premotor SMA Primary Somatosensory Primary Visual Primary Auditory Primary Motor
Multimodal Association Cortex Premotor SMA Primary Motor Hemiparesis Motor and Sensory Aspects of Cognition
Akinesia, Bimanual dyscoordination Motor and Sensory Aspects of Cognition Multimodal Association Cortex Premotor SMA Primary Motor
Motor and Sensory Aspects of Cognition ? Multimodal Association Cortex Apraxia Premotor SMA Primary Motor
Motor and Sensory Aspects of Cognition • Apraxia -- Inability to correctly perform learned skilled movements, not due to impaired basic motor function, impaired cognition, or impaired comprehension • Lesion: Inferior parietal lobule, corpus callosum, SMA
Multimodal Association Cortex Multimodal Association Cortex Premotor Premotor SMA SMA Primary Motor Primary Motor Motor and Sensory Aspects of Cognition Corpus Callosum ? Alien Hand
Motor and Sensory Aspects of Cognition Multimodal Association Cortex Visual Association Somatosensory Association Auditory Association Visual Loss Somatosensory Loss Auditory Loss Primary Visual Primary Somatosensory Primary Auditory
Motor and Sensory Aspects of Cognition Multimodal Association Cortex ? ? ? Visual Association Somatosensory Association Auditory Association Primary Visual Primary Somatosensory Primary Auditory
Motor and Sensory Aspects of Cognition • Agnosia -- Impairment of object recognition in the presence of relatively intact basic perception and language • Visual Object Agnosia • Prosopagnosia (agnosia for faces) • Tactile Agnosia • Auditory Agnosia
Motor and Sensory Aspects of Cognition ? Multimodal Association Cortex Visual Association Somatosensory Association Auditory Association Primary Visual Primary Somatosensory Primary Auditory
Motor and Sensory Aspects of Cognition • Hemispatial Neglect • Visuospatial Integration Deficits