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Diencephalon: Thalamus and Hypothalamus. January 13, 2009. Diencephalon. Relay between the brainstem & cerebral cortex Dorsal-posterior structures Epithalamus Habenular nuclei – integrate smell & emotions Pineal gland – monitors diurnal / nocturnal rhythm Thalamus Metathalamus
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Diencephalon:Thalamus and Hypothalamus January 13, 2009
Diencephalon • Relay between the brainstem & cerebral cortex • Dorsal-posterior structures • Epithalamus • Habenular nuclei – integrate smell & emotions • Pineal gland – monitors diurnal / nocturnal rhythm • Thalamus • Metathalamus • Medial geniculate body – auditory relay • Lateral geniculate body – visual relay • Ventral-anterior structure • Hypothalamus
Function of the Thalamus • Sensory relay • ALL sensory information (except smell) • Motor integration • Input from cortex, cerebellum and basal ganglia • Arousal • Part of reticular activating system • Pain modulation • All nociceptive information • Memory & behavior • Lesions are disruptive
Input to the Thalamus Metathalamus Vision and Hearing
Input to the Thalamus Sensory relay - Ventral posterior group all sensation frombody and head, including pain
Input to the Thalamus Motor control and integration
Input to the Thalamus Behavior and emotionconnection with hypothalamus
Projections from the Thalamus Metathalamus Vision and Hearing
Projections from the Thalamus Sensory relay Ventral posterior group all sensation frombody and head, including pain
Projections from the Thalamus Motor control and integration
Projections from the Thalamus Behavior and emotionconnection with hypothalamus
Thalamus: axial view Descending upper motor neurons Cerebral peduncles Internal capsule
Thalamus: coronal view 3rd ventricle
Thalamus: coronal view Internal capsule
Thalamus: coronal view Cerebral peduncles Internal capsule
Thalamus: coronal view Dorsomedial nucleus has reciprocal connections to prefrontal cortex. Concerned with judgment, decision making, memory and behavior. Mediodorsal nucleusInternal capsule
Thalamus VL nucleus has reciprocal connections with primary motor cortex. It receives input from cerebellar nuclei. With VA nucleus (which receives input from basal ganglia) contributes to planning and control of movement. Ventral lateral nucleus Mediodorsal nucleusInternal capsule
Hypothalamus Located ventral-anterior to thalamus. (Subthalamus, located ventral to thalamus, will be discussed with basal ganglia.)
Hypothalamus Coronal view
Hypothalamus Sagittal view
Hypothalamus Thalamus
Hypothalamus Optic chiasm
Hypothalamus Pituitary Gland
Hypothalamus Mammillary body: termination of fornix
Hypothalamus Fornix: part of the limbic system
Hypothalamus Coronal view Lateral view Fornix to mammillary bodies
Hypothalamus: sagittal view Connects temporal lobes, sharing olfactory and audiovisual information
Hypothalamus: coronal view(rostral to caudal) MAMMILLARY TUBERAL SUPRACHIASMATIC PRE-OPTIC
Hypothalamus: coronal view Pre-Optic Region Gonadotropic releasing hormone Sexual arousal, appetite, reproduction
Hypothalamus: coronal view Suprachiasmic Region Secrete ADH, oxytocin Transported via axons to posterior pituitary (hypophysis)
Hypothalamus: coronal view Regulates thirst
Hypothalamus: coronal view Body temperature Circadian rhythms
Hypothalamus: coronal view Tuberal Region Satiety
Hypothalamus: coronal view Regulates prolactin and growth hormone β endorphin for pain
Hypothalamus: coronal view Mammillary region Limbic system
Hypothalamus: coronal view Hypocretin (orexin) Narcolepsy, reward