The Hypothalamus Medical Neuroscience Dr Wiegand Neural Influences

The Hypothalamus Medical Neuroscience Dr. Wiegand

Neural Influences Hormonal Influences The Hypothalamus Autonomic Nervous System Limbic System Endocrine System

Functions of the Hypothalamus Autonomic nervous system regulation ¢ Hormone production ¢ Endocrine regulation ¢ Circadian rhythm regulation ¢ Limbic system interaction ¢ Various ¢ Temperature regulation l Feeding l

The Diencephalon

The Diencephalon x i n r thalamus fo Epithalamus (Pineal & Habenula) hypothalamus Optic chiasm pituitary Mammillary subthalamus body

Pituitary

Divisions of the Hypothalamus 3 rd ventricle

Divisions of the Hypothalamus periventricular medial lateral

Divisions of the Hypothalamus

Divisions of the Hypothalamus

Tuberoinfundibular tract Hypothalamic. Hypophysial Portal System Hypothalamohypophysial tract

Functions of the Hypothalamus ¢ ¢ ¢ Autonomic nervous system regulation Hormone production Endocrine regulation Circadian rhythm regulation Limbic system interaction Various l l Temperature regulation Feeding ¢ ¢ Anterior area influences PSNS through projections to brainstem PSNS nuclei Posterior area influences SNS through projections to the lateral gray horn

Functions of the Hypothalamus ¢ ¢ ¢ Autonomic nervous system regulation Hormone production Endocrine regulation Circadian rhythm regulation Limbic system interaction Various l l Temperature regulation Feeding ¢ ¢ Magnocellular regions of the supraoptic and paraventricular nuclei produce oxytocin and vassopressin (ADH) Transported via axonal transport systems (hypothalamohypophysial tract) to neurohypophysis Released in circulation Damage to supraoptic n. diabetes insipidus

Functions of the Hypothalamus ¢ ¢ ¢ Autonomic nervous system regulation Hormone production Endocrine regulation Circadian rhythm regulation Limbic system interaction Various l l Temperature regulation Feeding ¢ Stimulating or inhibiting hormones are transported via the tuberoinfundibular tract and released in to the pituitary portal system and ultimately to the adenohypophysis

Functions of the Hypothalamus ¢ ¢ ¢ Autonomic nervous system regulation Hormone production Endocrine regulation Circadian rhythm regulation Limbic system interaction Various l l Temperature regulation Feeding ¢ Input from retina to suprachiasmatic nucleus is then sent through poorly defined projections to the pineal gland

Functions of the Hypothalamus ¢ ¢ ¢ Autonomic nervous system regulation Hormone production Endocrine regulation Circadian rhythm regulation Limbic system interaction Various l l Temperature regulation Feeding ¢ Temperature l l ¢ Posterior n. conserves heat Anterior n. dissipates heat Fever starts – sweating Fever ends – chills Feeding l l Lateral n. induces eating Ventromedial n. inhibits eating

Limbic System (Visceral Brain) Mediates complex behaviors l Preservation of species • securing food, defense mechanisms, sexual behavior Emotions l Affective behavior l Memory l Motivation l

Components ¢ ¢ ¢ ¢ Cingulate gyrus Parahippocampal gyrus Mammillary body Hippocampus Anterior thalamic nucleus Amygdala Septal nuclei Dorsomedial thalamic nucleus

Circuit of Papez Cingulate Gyrus Thalamocingulate radiations fornix Mammillary Body cingulum Ant. Thalamic Nucleus Hippocampus Mammillothalamic tract

Fornix

Amygdala ¢ ¢ Located deep to uncus, near tail of caudate, and above most rostral part of lateral ventricle inferior horn Wide variety of functions, connections l ¢ lip smacking, chewing, autonomic responses, fear, rage, anxiety Klüver-Bucy Syndrome Placidity Visual agnosia Oral tendencies Hypersexuality