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52 Cards in this Set
- Front
- Back
Which brain structures project to the cortex via the thalamus? |
- Spinal Cord
- Brainstem - Cerebellum - Basal Ganglia |
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What is the location of the Diencephalon embryologically? and in the developed brain?
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- Between the Telencephalon and the Mesencephalon
- Between the cerebral cortex and the brainstem, medial to internal capsule |
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What separates the Diencephalon into two pieces?
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Third Ventricle
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What are the subdivisions of the Diencephalon?
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- EPITHALAMUS (habenula, pineal gland, posterior commissure)
- DORSAL THALAMUS / THALAMUS (thalamic nuclei, external and internal medullary lamina) - VENTRAL THALAMUS (reticular nucleus and ventral lateral geniculate nucleus-vLGN) - SUBTHALAMUS (zona incerta and subthalamic nucleus) - HYPOTHALAMUS (hypothalamic nuclei, infundibulum, hypophysis, hypophyseal portal system) |
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What are the components of the Epithalamus? Functions?
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- Habenula - part of limbic pathway
- Pineal Gland - synthesizes serotonin and converts to melatonin - Posterior Commissure - links pretectal and other nuclei of the two sides |
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What are the components of the Dorsal Thalamus / Thalamus? Function/Location?
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- Thalamic Nuclei - strong link to cerebral cortex
- External Medullary Lamina - myelinated fibers on lateral edge of thalamus - Internal Medullary - myelinated fibers separating thalamus into medial and lateral parts |
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What are the components of the Ventral Thalamus?Location?
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- Reticular Nucleus of Thalamus - external to ext. medullary lamina and internal to int. capsule (NAVY)
- Ventral Lateral Geniculate Nucleus (vLGN) |
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What are the components of the Subthalamus? Locations?
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- Located between the hypothalamus and dorsal thalamus
- Zona incerta - rostral continuation of reticular formation of brainstem (GREEN) - Subthalamic Nucleus - part of basal ganglia (PINK) |
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What are the components of the Hypothalamus? Location?
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- Separated by hypothalamic sulcus
- Hypothalamic Nuclei (ORANGE) - Infundibulum - stalk connecting the hypothalamus and pituitary gland - Hypophysis - Pituitary gland - Hypophyseal Portal System |
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What is the function of the Hypothalamus?
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- Controlling center of ANS
- Neurobehavioral functions - Regulation of hormones released by hypophysis |
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What is the blood supply to the thalamus?
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Branches from Circle of Willis:
- Anterior Communicating Artery - Posterior Communicating Artery - Anterior Cerebral Artery - Posterior Cerebral Artery - Internal Carotid Artery |
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What is the location of the Thalamus?
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- Medial to the posterior limb of the internal capsule
- Surrounds the 3rd Ventricle (splits it medially) |
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What is the Thalamus derived from embryologically?
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Diencephalon
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What are the sensory functions of the Thalamus?
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- Relays all sensory information to the cerebral cortex (olfactory input to thalamus is from the piriform cortex)
- Integrates sensory information from different modalities and projects to association cortex |
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What are the motor functions of the Thalamus?
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Relays information about motor activities to the cerebral cortex
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Aside from sensory and motor functions, what are the roles of the Thalamus?
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- Relays emotional and affective information to cortex
- Part of "Papez circuit" of Limbic system - projects to limbic cortex - Involved in control of alertness, arousal, and sleep |
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What circuit is the Thalamus apart of?
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"Papez Circuit" - of the Limbic system - projects to Limbic cortex
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What feedback control does the Thalamus experience?
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Direct cortical feedback and control - reciprocal connections between thalamus and cortex
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What are the SPECIFIC Relay nuclei groups / tiers of the Thalamus?
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- Anterior Nuclear Group
- Lateral-Ventral Tier - Lateral-Dorsal Tier - Medial Group |
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"Anterior Nuclear Group"
- Specific/Non-Specific - Afferent Input - Efferent Output - Functions |
- Specific
- Mammillary Body - Cingulate Gyrus - Limbic |
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What are the divisions of the Lateral-Ventral Tier of Specific Relay Nuclei of the Thalamus?
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- VA = Ventral Anterior
- VL = Ventral Lateral - VPL = Ventral Posterior Lateral - VPM = Ventral Posterior Medial - LGN = Lateral Geniculate Nucleus - MGN = Medial Geniculate Nucleus |
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"VA = Ventral Anterior"
- Specific/Non-Specific; Group/Tier - Afferent Input - Efferent Output - Functions |
- Specific - Lateral-Ventral Tier
- Globus Pallidus - Premotor Cortex (area 6) - Motor |
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"VL = Ventral Lateral"
- Specific/Non-Specific; Group/Tier - Afferent Input - Efferent Output - Functions |
- Specific - Lateral-Ventral Tier
- Dentate Nucleus of Cerebellum - Motor and Premotor (areas 4 and 6) - Motor |
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"VPL = Ventral Posterior Lateral"
- Specific/Non-Specific; Group/Tier - Afferent Input - Efferent Output - Functions |
- Specific - Lateral-Ventral Tier
- Dorsal column (medial lemniscus and spinothalamic) - Somatosensory Cortex (areas 3, 1, 2) - Somatic Sensation (body) |
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"VPM = Ventral Posterior Medial"
- Specific/Non-Specific; Group/Tier - Afferent Input - Efferent Output - Functions |
- Specific - Lateral-Ventral Tier
- Sensory nuclei of Trigeminal N. - Somatosensory Cortex (areas 3, 1, 2) - Somatic Sensation (face) |
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"LGN = Lateral Geniculate Nucleus"
- Specific/Non-Specific; Group/Tier - Afferent Input - Efferent Output - Functions |
- Specific - Lateral-Ventral Tier
- Retinal Ganglion Cells - Primary Visual Cortex (area 17) - Vision |
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"MGN = Medial Geniculate Nucleus"
- Specific/Non-Specific; Group/Tier - Afferent Input - Efferent Output - Functions |
- Specific - Lateral-Ventral Tier
- Inferior Colliculus - Primary Auditory Cortex (area 41, 42) - Audition |
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What are the divisions of the Lateral-Dorsal Tier of Specific Relay Nuclei of the Thalamus?
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- LD = Lateral Dorsal
- LP = Lateral Posterior - Pul = Pulvinar |
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"LD = Lateral Dorsal"
- Specific/Non-Specific; Group/Tier - Afferent Input - Efferent Output - Functions |
- Specific - Lateral-Dorsal Tier
- Cingulate Gyrus - Cingulate Gyrus - Emotional Expression |
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"LP = Lateral Posterior"
- Specific/Non-Specific; Group/Tier - Afferent Input - Efferent Output - Functions |
- Specific - Lateral-Dorsal Tier
- Parietal Cortex - Parietal Cortex - Sensory integration |
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"Pul = Pulvinar"
- Specific/Non-Specific; Group/Tier - Afferent Input - Efferent Output - Functions |
- Specific - Lateral-Dorsal Tier
- Superior colliculus, parietal, occipital, and temporal lobes - Parietal, occipital, and temporal lobes (POT) - Integration of sensory information |
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"MD = Medial Dorsal"
- Specific/Non-Specific; Group/Tier - Afferent Input - Efferent Output - Functions |
- Specific - Medial-Dorsal Group
- Amygdaloid nuclear complex, olfactory, hypothalamus - Prefrontal Cortex - Limbic |
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What are the diffuse-projection nuclei (non-specific)?
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- Midline nuclei
- Intralaminar Nuclei (CM - centro-median; CL - centro-lateral; PF - parafascicularis) - Reticular Nucleus |
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Midline Nuclei
- Specific/Non-Specific; Group/Tier - Afferent Input - Efferent Output - Functions |
- Non-specific - diffuse projection nuclei
- Reticular formation and hypothalamus - Basal forebrain - Limbic |
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Intralaminar Nuclei
- Specific/Non-Specific; Group/Tier - Afferent Input - Efferent Output - Functions |
- Non-specific - diffuse projection nuclei
- Reticular formation, spinothalamic tract, globus pallidus, and cortical areas - Basal ganglia and wide areas of cortex - Role in pain, sleep, and wakefulness |
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Reticular Nucleus
- Specific/Non-Specific; Group/Tier - Afferent Input - Efferent Output - Functions |
- Non-specific - diffuse projection nuclei
- Cortex, thalamus, brainstem reticular formation - Thalamic nuclei - Modulation of thalamic activity |
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Which thalamic nuclei are involved in limbic functions?
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- Anterior Nuclear Group (specific relay nuclei)
- Medial Group (MD) (specific relay nuclei) - Midline Nuclei (diffuse-projection nuclei; non-specific) |
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Which thalamic nuclei are involved in motor functions?
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- VA = Ventral Anterior
- VL = Ventral Lateral - Both: lateral-ventral tier of specific relay nuclei |
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Which thalamic nuclei are involved in somatic sensory functions?
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- VPL - Ventral Posterior Lateral (somatic sensation of body)
- VPM - Ventral Posterior Medial (somatic sensation of face) - VPL & VPM: lateral-ventral tier of specific relay nuclei - LP - Lateral Posterior (sensory integration) - Pul - Pulvinar (sensory integration) - LP & Pul: lateral-dorsal tier of specific relay nuclei |
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Which thalamic nuclei are involved in vision functions?
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- Lateral Geniculate Nuclei (LGN)
- Lateral-ventral tier of specific relay nuclei |
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Which thalamic nuclei are involved in auditory functions?
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- MGN - Medial Geniculate Nuclei
- Lateral-ventral tier of specific relay nuclei |
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Which thalamic nuclei are involved in emotional expression?
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- LD - Lateral Dorsal
- Part of lateral-dorsal tier of specific relay nuclei |
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Which thalamic nuclei are involved in pain, sleep, and wakefulness?
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- Intralaminar Nuclei: Centro-Median (CM), Centro-Lateral (CL), and Parafascicularis (PF)
- All part of Diffuse-projection nuclei (non-specific system) |
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Which thalamic nuclei are involved in modulation of thalamic nuclei?
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- Reticular Nucleus
- Part of Diffuse-projection nuclei (non-specific system) |
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How do neurons interact in the Thalamic Neuronal Circuit?
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- Afferent input projects to Thalamic Relay Neuron directly or indirectly via Thalamic Interneuron
- Thalamus connected bidirectionally with the Cerebral Cortex via Thalamic Relay Neurons |
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What are the typical responses in the Sensory Thalamic Relay Neurons?
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- Single cell response in VPL of human during therapeutic surgery
- Bursts of discharge in specific sensory relay nucleus of VPL - Stimulus was a light stroke across the dorsum of the contralateral middle finger |
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What can cause Thalamic Syndrome?
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- Vascular lesion or tumor (relatively rare)
- Damages lateral group of thalamic nuclei (VPL) |
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What are the symptoms of Thalamic Syndrome (damage to lateral group of thalamic nuclei)?
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- Initially a transitory contralateral hemianalgesia
- Soon, painful sensations appear with noxious stimuli - Later, pain is provoked by pressure, touch, and vibration - Eventually, state of spontaneous, constant or paroxysmal pain evoked on affected side (contralateral to lesion) w/o any external stimulus = Dysesthesia - Threshold for somatic sensation raised on affected side; once threshold reached, pain has strong emotional overtone to it |
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What does Dysesthesia mean?
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- A state of spontaneous, constant or paroxysmal pain is evoked on the affected side (contralateral to the lesion) without any external stimulus
- An abnormal unpleasant sensation felt when touched, caused by damage to peripheral nerves |
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What can activate the non-specific system of the thalamus? Response?
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- Repetitive, low-frequency stimulation of the non-specific thalamic nuclei
- Cortical recruitment response which waxes and wanes - Controls level of excitability of neurons over wide areas of cortex |
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How are the non-specific nuclei of the thalamus connected?
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Interconnected with each other and reciprocally with specific thalamic nuclei
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What is the function of the Non-specific nuclei of the thalamus (reticular activating system- RAS)?
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Controls level of excitability of neurons over wide areas of cortex
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