Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Neuroscience: Exploring the Brain, 3e Chapter 15: Neuroendocrine system: Chemical Control of the Brain and Behavior

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Introduction Synaptic Connections –Point-to-point Restricts synaptic communication –Brain areas with expanded influence over space and time Secretory hypothalamus Autonomic nervous system (ANS) Diffuse modulatory systems

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins The Secretory Hypothalamus Function –Difference between hypothalamus and dorsal thalamus Hypothalamus defect –Fatal disruption to body function Dorsal thalamus defect –Blind spot, lack of feeling

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Homeostasis –Regulatory process: Regulates body temperature and blood composition Hypothalamus commands in cold weather Shiver, goosebumps, turn blue Hypothalamus commands in hot weather Turn red, sweat The Secretory Hypothalamus

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins The Secretory Hypothalamus Structure of the Hypothalamus

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Pathways to the Pituitary –Two neurohormones –Oxytocin Lactation, suppress hypothalamic function –Vasopressin Regulate blood volume and salt concentration The Secretory Hypothalamus: Neurosecretory neurons of the periventricular zone.

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Communication between kidneys and brain The Secretory Hypothalamus

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Hypothalamic Control of the Anterior Pituitary –Controlled by parvocellular neurosecretory cells Secrete hypophysiotropic (‘releasing’) hormones Hypothalamiopituitary portal circulation Pituitary cells secrete or stop secreting hormones The Secretory Hypothalamus

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Stress Response –Periventricular hypothalamus secretes CRH into portal circulation. –ACTH released into circulation. –ACTH stimulates cortisol release from adrenal cortex. The Secretory Hypothalamus

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Divisions of autonomic nervous system (ANS) –Sympathetic division Increased heart rate and blood pressure Depressed digestive function Mobilized glucose reserves –Parasympathetic division Slower heart rate, fall in pressure Increased digestive functions Stop sweating The Autonomic Nervous System

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins ANS Circuits versus Somatic Motor System The Autonomic Nervous System

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins The Autonomic Nervous System Sympathetic and Parasympathetic Divisions

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins The Enteric Division –Location: Lining of esophagus, stomach, intestines, pancreas, and gallbladder –Composition: Two complicated networks- myenteric (Auerbach's) plexus and submucous (Meissner's) plexus –Function: Control physiological processes involved in transport, digestion of food –Inputs: From brain via axons of the sympathetic and parasympathetic divisions The Autonomic Nervous System

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Central Control of the ANS –Connections for autonomic control Periventricular zone connections to brain stem and spinal cord nuclei Nucleus of solitary tract –Function of solitary nucleus Integrates sensory information from internal organs and coordinates output The Autonomic Nervous System

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Neurotransmitters and the Pharmacology of Autonomic Function –ANS: Better understanding of drug mechanisms influencing synaptic transmission (vs. CNS) Preganglionic Neurotransmitters –ACh: Binds to nAChR, evokes fast EPSP –Ganglionic ACh: Also activates mAChR, slow EPSPs and IPSPs –Preganglionic terminals: Small EPSPs The Autonomic Nervous System

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Postganglionic Neurotransmitters –Parasympathetic: Release Ach Local effect –Sympathetic: Release NE Far-reaching effects –Parasympathomimetic: Mimic or promote muscarinic actions of ACh or inhibit actions of NE –Sympathomimetic: Mimic or promote NE actions or inhibit muscarinic actions of ACh The Autonomic Nervous System

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomy and Functions –Four systems with common principles: Small set of neurons at core Arise from brain stem One neuron influences many others Synapses release transmitter molecules into extracellular fluid The Diffuse Modulatory Systems of the Brain

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Anatomy and Functions –Four systems with common principles: Noradrenergic Locus Coeruleus Serotonergic Raphe Nuclei Dopaminergic Substantia Nigra and Ventral tegmental Area Cholinergic Basal Forebrain and Brain Stem Complexes The Diffuse Modulatory Systems of the Brain

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Noradrenergic Locus Coeruleus The Diffuse Modulatory Systems of the Brain

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins The Nonadrenergic Locus Coeruleus –Path: Axons innervate cerebral cortex, thalamus, hypothalamus, olfactory bulb, cerebellum, midbrain, spinal cord –Function: Regulation of attention, arousal, sleep- wake cycles, learning and memory, anxiety and pain, mood, brain metabolism –Activation: New, unexpected, nonpainful sensory stimuli The Diffuse Modulatory Systems of the Brain

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins The Diffuse Modulatory Systems of the Brain The Serotonergic Raphe Nuclei

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins The Serotonergic Raphe Nuclei –Path: Innervate many of the same areas as noradrenergic system –Function: Together with noradrenergic system, comprise the ascending reticular activating system. Raphe system particularly involved in sleep/wake cycles. Also mood –Activation: New, unexpected, nonpainful sensory stimuli The Diffuse Modulatory Systems of the Brain

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Dopaminergic Substantia Nigra and Ventral Tegmental Area The Diffuse Modulatory Systems of the Brain

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Dopaminergic Substantia Nigra and Ventral Tegmental Area Substantia Nigra Projects to the striatum Facilitates the initiation of voluntary movements(Parkinson’s Disease) –Ventral tegmental area Innervates circumscribed region of telecephalon Mesocorticolimbic dopamine system: Dopaminergic projection from midbrain The Diffuse Modulatory Systems of the Brain

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Cholinergic Systems The Diffuse Modulatory Systems of the Brain

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Cholinergic Systems –Basal forebrain complex Core of telencephalon, medial and ventral to basal ganglia Function: Unknown, participates in learning and memory –Pontomesencephalotegmental complex Releases ACh Function: Regulates excitability of thalamic sensory relay nuclei The Diffuse Modulatory Systems of the Brain

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Drugs and the Diffuse Modulatory Systems –Psychoactive drugs: Act on CNS –Many drugs of abuse act on modulatory systems LSD, Psilocybe mushrooms, and peyote close to structure of serotonin Cocaine and amphetamine affect dopaminergic and noradrenergic systems - sympathomimetic The Diffuse Modulatory Systems of the Brain

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Stimulants: Block reuptake –Cocaine targets DA reuptake –Amphetamine blocks NE and DA reuptake and stimulates DA release The Diffuse Modulatory Systems of the Brain

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins Concluding Remarks Three Components of the Nervous System That Have Great Reach of Their Influences –Secretory hypothalamus (all over the body) –Autonomic nervous system (all over the body) –Diffuse modulatory systems (all over the brain) Detailed level – Each system performs different functions General level –All work to maintain brain homeostasis

Copyright © 2007 Wolters Kluwer Health | Lippincott Williams & Wilkins End of Presentation