Teo Physio Hypothalamus Limbic PDF

# Theoretical Lesson ## Animal Body Function VII | AMFII ### Neuroendocrine Integration and Regulation #### Hypothalamus and Limbic System #### Nervous System **Nataniel Rosa, DVM, MVSc** **[email protected]** ## Summary - Physiology: functions of Hypothalamus & Limbic System; - Neuroen...

# Theoretical Lesson ## Animal Body Function VII | AMFII ### Neuroendocrine Integration and Regulation #### Hypothalamus and Limbic System #### Nervous System **Nataniel Rosa, DVM, MVSc** **[email protected]** ## Summary - Physiology: functions of Hypothalamus & Limbic System; - Neuroendocrine Control and Regulation: Hypothalamus as the main integrating center and coordinator of responses: Endocrine (Endocrine System), Nervous (Autonomic Nervous System), Behavioral (Limbic System) - Examples of integrated responses: Temperature Control - Limbic System: Motivated behaviors, emotions, learning and memory; Reward and punishment centers; Amygdala, Hippocampus, Thalamus ## Diencephalon - Is a division of the forebrain = embryonic prosencephalon. - It is situated between the telencephalon and the midbrain. - It consists of structures that are on either side of the third ventricle, including the thalamus, the hypothalamus, the epithalamus and the subthalamus. ## Thermoregulation - **Controlled condition Temperature 36.5°C** - **Primary Somatosensory Cortex** - **Integrator center hypothalamus limbic system** - **Hormonal, Autonomic, and Behavioral Adjustments** - **efferent signals** - **Effector organs** - **skeletal muscle** - **smooth muscle of the vessels** - **sweat glands** - **skeletal muscle** - **smooth muscle of vessels** - **anterior pituitary → thyroid** - **Response** - **Less muscle activity** - **Relaxation → vasodilation** - **Increases perspiration** - **tremors** - **vasoconstriction** - **thyroid hormones** - **↑ metabolism** - **Initial stimulus: Changes of temperature** - **Increase** - **Decrease** - **afferent signals** - **Thermoreceptors** - **Central (anterior hypothalamus) and peripheral (skin)** - **Feedback** - **Changes behavioral** ## Hypothalamus: Temperature Regulation - **Hypothalamus area** - **function** - **lesion causes** - **Electrical stimulation causes** - **Preoptic area (and anterior nucleus)** - **heat dissipation** - **Chronic hyperthermia** - **vasodilation (skin)** - **suppression tremors** - **pants** - **Posterior area** - **heat conservation** - **Hypothermia (in cold environment)** - **vasoconstriction (skin)** - **muscle tremors** - **thyroxine increase** ## Hypothalamus integrates peripheral and central temperature information - **Normal environment temperature** - **Fan OFF** - **Response rate** - **Elevated environment temperature** - **Fan ON** - **Room temperature** - **Hypothalamic temperature** - **Normal environment temperature Hypothalamus heated** - **Fan ON** ## Hypothalamus: functions - **Temperature** - **Pressure arterial** - **Thirst and hunger** - **Integration** - **Reproduction** - **Growth** - **Pregnancy and lactation** - **Regulation** - **Behaviors** - **Escape or fight** ## Hypothalamus: nuclei and functions - **Hypothalamus is composed of small nervous cells which are arranged in groups called hypothalamic nuclei. Many of these nuclei are not clearly demarcated from each other. Even some may show overlapping.** - **Anterior commissure** - **Preoptic nucleus** - **Anterior hypothalamic nucleus** - **Supraoptic nucleus** - **Suprachiasmatic nucleus** - **Optic chiasma** - **Infundibulum (stalk of the pituitary gland)** - **Paraventricular nucleus** - **Fornix** - **Dorsomedial nucleus** - **Posterior hypothalamic nucleus** - **Lateral hypothalamic area** - **Ventromedial nucleus** - **Arcuate nucleus** - **Mammillary body** - **Pituitary gland** ## Hypothalamus: nuclei and functions - **Anterior nucleus** - **thermal regulation (dissipation of heat)** - **stimulates parasympathetic NS** - **destruction results in hyperthermia** - **Posterior nucleus** - **thermal regulation (conservation of heat)** - **destruction results in inability to thermoregulate** - **stimulates the sympathetic NS** - **Midbrain** - **Hypothalamus area** - **function** - **lesion causes** - **Electrical stimulation causes** - **Preoptic area (and anterior nucleus) heat dissipation** - **Chronic hyperthermia** - **vasodilation (skin)** - **suppression tremors** - **pants** - **Posterior area (posterior nucleus) heat conservation** - **Hypothermia (in cold environment)** - **vasoconstriction (skin)** - **muscle tremors** - **thyroxine increase** ## Hypothalamus : nuclei and functions - **Paraventricular and supraoptic nuclei** - **regulate water balance** - **produce ADH and oxytocin** - **destruction causes diabetes insipidus** - **paraventricular nucleus projects to autonomic nuclei of brainstem and spinal cord** ## Hypothalamus : nuclei and functions - **Suprachiasmatic nucleus** - **receives input from retina** - **controls circadian rhythms** ## Hypothalamus : nuclei and functions - **Dorsomedial nucleus** - **stimulation results in obesity and savage behavior** - **Lateral nucleus** - **stimulation induces eating** - **destruction results in starvation** - **Ventromedial nucleus** - **satiety center** - **destruction results in obesity and savage behavior** ## Hypothalamus: afferent and efferent pathways - **Afferent pathways** - **Hippocampus** - **Amygdala** - **Retina** - **Olfactory cortex** - **Diffuse projection from the brainstem** - **Solitary tract nucleus** - **Parabrachial nucleus** - **(Cortex) septum** - **Efferent pathways** - **Posterior Pituitary** - **Adeno hypophysis (via blood)** - **Intermediolateral column of the medulla** - **Nucleus of the solitary tract** - **Parabrachial nucleus** - **Amygdala** - **Hippocampus** - **thalamus** - **Efferent nuclei of cranial cores** - **Reticular formation** ## Hypothalamus controls Endocrine System and Autonomic Nervous System - **Hypothalamus** - **Systems** - **Endocrine** - **Autonomic** - **Limbic** - **Responses** - **Hormonal** - **Autonomous ** - **Behavioral** - **Posterior pituitary** - **Anterior pituitary (via blood)** - **intermediate column side of the medulla** - **Nuclei of the solitary tract and Parabrachial nucleus** - **Amygdala** - **Hippocampus** - **Thalamus** - **Efferent nucleus of cranial nucleus reticular formation** ## Hypothalamus controls the Endocrine System - **Hypothalamus** - **Hypothalamus pituitary gland** - **Hypothalamus-pituitary axis (endocrine control)** - **Hypohysis cereb (Pituitary gland)** - **Adrenal gland** - **Pineal gland Pineal** - **Adrenal** - **Parathyroid glands** - **Parathyroid Thyroid gland** - **Thyroid** - **Adenohypophysis Neurohypophysis** - **Anterior pituitary Posterior pituitary** - **Pituitary gland** - **Ovaries** - **Kidne** - **Ove** - **Placenta (female)** - **Pancreas** - **Testis (male)** - **Testicles** ## Hypothalamus controls Endocrine System and Autonomic Nervous System - **Hypothalamus** - **System** - **Endocrine** - **Autonomic** - **Limbic** - **Response** - **Hormonal** - **Autonomous ** - **Behavioral** - **Neurohypophysis** - **Adenohypophysis (via blood)** - **Intermediate column of the medulla** - **Nuclei of the solitary tract and Parabrachial nucleus** - **Amygdala** - **Hippocampus** - **Thalamus** - **Efferent nucleus of cranial nucleus reticular formation** ## Hypothalamus controls the Autonomic Nervous System - **Sympathetic Nervous System** - **Sympathetic division** - **Parasympathetic Nervous System** - **Parasympathetic division** - **Autonomic Reflex Arc (A neural pathway that controls an action reflex)** - **Long Reflex** - **Postganglionic fibers** - **Preganglionic fibers** - **Short Reflex** - **Sensory cell synapses in spinal cord or brain** - **Sensory receptor cell** - **Sensory cell synapses only in peripheral ganglion** - **Sensory receptor cell** - **Sensation** - **Peripheral ganglion** - **Sensation** ## Integration of Endocrine System and Nervous System responses - **The endocrine system works together with the nervous system to influence many aspects of human behavior, including growth, reproduction, and metabolism.** - **Property** - **Endocrine reflex** - **Nervous reflex** - **Nature of the signal** - **Chemical (hormones)** - **Electric (with or without) neurotransmitter** - **Specificity** - **Receptor** - **Each neuron / target cell(s)** - **Speed and duration** - **Prolonged** - **Fast** - **Codification of the stimulus** - **Proportional to quantity** - **Signals identical in strength - frequency modulation** ## Hypothalamus coordinates expression of emotional states and behavioral responses along with other parts of the Limbic System ## Emotion vs Feeling - **Aspect** - **Emotion** - **Definition** - **A complex psychological and physiological response to a stimulus.** - **Origin** - **Initiated by subconscious brain processes (e.g., amygdala activation).** - **Timeframe** - **Typically automatic and fast-acting, lasting seconds.** - **Physiological Basis** - **Involves bodily responses (e.g., heart rate, sweating, hormonal changes) regulated by the nervous system.** - **Consciousness** - **Largely unconscious or semi-conscious; occurs even without active thought.** - **Universality** - **Emotions are more universal and biologically hardwired (e.g., fear, anger, joy).** - **Function** - **Drives immediate adaptive behavior, such as fight, flight, or social bonding.** - **Feeling** - **Definition** - **The subjective, conscious experience of an emotion.** - **Origin** - **Arises from conscious interpretation of an emotion, influenced by thoughts and awareness.** - **Timeframe** - **Can persist longer and is shaped by reflection, memories, and personal meaning.** - **Physiological Basis** - **Less tied to immediate physical responses, focusing on mental interpretation of these states.** - **Consciousness** - **Fully conscious; requires awareness to recognize and articulate.** - **Universality** - **Feelings are more subjective and influenced by personal, cultural, and social factors.** - **Function** - **Contributes to self-awareness, reflection, and meaning-making.** ## What are the functions of emotions? ## Classifying dogs' facial expressions from photographs (Bloom & Friedman, 2013) - **Scientists believe humans have developed a natural empathy with dogs and can read their facial expressions** - **In which of the photos is the dog sad, happy or aggressive?** ## More... what are the functions of emotions? ## More... what are the functions of emotions? - **The Case of Phineas Gage** ## The Case of Phineas Gage - **In 1848, in Vermont, an incident occurred which was to change our understanding of the relation between mind and brain.** - **Phineas P Gage, a 25 year old railroad foreman, was excavating rock. In preparation for blasting he was tamping powder into a drill hole, he was inserting a tamping iron-1.1 m long, 6 mm in diameter, and weighing 6 kg when** ## The Case of Phineas Gage - **Gage's employers, "who regarded him as the most efficient and capable foreman ... considered the change in his mind so marked that they could not give him his place again.... He became fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom), manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires.... A child in his intellectual capacity and manifestations, he has the animal passions of a strong man.... His mind was radically changed, so decidedly that his friends and acquaintances said he was 'no longer Gage.'** ## Darwin and the emotions - **"The Expression of the Emotions in Man and Animals" (1872)** - **Communication functions and preparation for behavioral responses.** - **Relevance of studying emotion in animal models;** - **Autonomic and musculoskeletal responses are an intrinsic part of emotional experience;** ## Importance of emotions - **Evolutionary Role** - **evolved to increase the chances of survival and reproduction. E.g.:** - **Fear triggers avoidance of danger;** - **Joy reinforces behaviors that enhance well-being** - **Social function (interactions)** - **Communication and bonding eg Reproduction** - **Action preparation** - **Decision-making** - **guide behavior and prioritization of actions in uncertain or complex situations** - **Learning** ## Peripheral components of emotions - **Musculoskeletal System and Autonomic Nervous System Functions:** - **Communication (from emotional states to other animals)** - **Preparing the body for action** - **Arousal (general and specific)** - **Improved physical and intellectual performance** ## Emotions vs Feelings - **Emotional state, Emotion (physical sensation)** - **Tachycardia ("heart racing")** - **Peripheral autonomic, endocrine, musculoskeletal responses; mediated by the hypothalamus, amygdala, and brainstem** - **Stimulus** - **Processing neocortical** - **Processing subneocortical** - **Conscious feeling** - **Fear** - **Mediated by the cerebral cortex (in part by the cingulate and frontal lobes)** - **Periphery** - **musculoskeletal system and autonomic nervous** ## The theory of emotion: Cannon-Bard - **"Hypothalamus and subcortical structures mediate both cognitive and emotional aspects of emotions"** - **Emotional event** - **Hypothalamus and subcortical structures** - **Peripheral changes Autonomic Nervous System e.g. increased heart rate)** - **Recognition by the cortex: conscious emotional experience (e.g. fear)** ## The theory of emotion: Cannon-Bard - **"Hypothalamus and subcortical structures mediate both cognitive and emotional aspects of emotions"** - **Posterior hypothalamus** - **Anterior hypothalamus** - **Mammillary body** - **Coordinated rage response** - **Coordinated rage response** - **No coordinated rage response** - **Stimulation of hypothalamic nuclei triggers autonomic and somatic responses characteristic of anger** - **Lesion:** - **Medial hypothalamus = aggressiveness, extreme arousal** - **Lateral hypothalamus = placidity** ## The theory of emotions: Damasio - **"Feelings are cognitive translations of ambiguous peripheral signals"** - **Emotional event** - **Hypothalamus and subcortical structures** - **Peripheral changes Autonomic Nervous System e.g. increased heart rate)** - **Individual expectations and social context** - **Recognition by the cortex: conscious emotional experience (e.g. fear)** ## The search for the cortical representation of feelings led to the discovery of the Limbic System - **Cingulate gyrus** - **Corpus callosum** - **Fornix** - **thalamus** - **Basal ganglia** - **Dentate gyrus** - **Mamlaryody** - **hypothalamus** - **Hippocampus** - **Amygdala Parapocampal gyrus** - **olfactory bulb** - **Hypophysis** - **James Papez** ## Amygdala - part of the limbic system most specifically involved in emotional experience - **Amygdala** - **Electrical stimulation → fear** - **Lesion → meekness, docility** - **Urbach-Wiethe disease** - **Inability to discern fear and slight differences in the facial expressions of others (amygdala = implicit memory detecting facial emotional cues; disruption of unconscious processing)** - **But continue to recognize familiar faces (inferior temporal cortex = explicit memory of facial identity)** ## Amygdala - part of the limbic system most specifically involved in emotional experience - **Thalamus** - **Septal area** - **Anterior cingulate cortex** - **Orbital cortex** - **Stria terminalis** - **Olfactory bulb** - **Hippocampus** - **Amygdala** - **Hypothalamus** - **afferent pathways** - **Thalamus** - **Septal area** - **Anterior cingulate cortex** - **Orbital cortex** - **Stria terminalis** - **Olfactory bulb** - **Hippocampus** - **Hypothalamus** - **Amygdala** - **efferent pathways** - **"window" through which the limbic system sees an animal's place in the world** - **Consisting of several cores:** - **basolateral nucleus: behaviors** - **corticomedial nucleus: olfactory stimuli** ## Amygdala functions - effects of nuclei stimulation - **Effects initiated from the amygdala and mediated by the hypothalamus** - **Increases or decreases in blood pressure, heart rate, motility, and gastrointestinal secretion** - **defecation and urination** - **Pupillary dilation or constriction** - **Piloerection** - **Hormonal secretion in the anterior pituitary: gonadotropins and ACTH.** ## Amygdala functions - effects of nuclei stimulation - **Causes involuntary movements:** - **Tonics (raising the head or tilting the body)** - **Circular movements** - **Clonic and rhythmic** - **Associated with smell and food (licking, chewing and swallowing)** - **Behaviors and sexual activity:** - **Anger, flight, punishment, severe pain, and fear (similar to the anger pattern triggered from the hypothalamus).** - **Reward and pleasure reactions** - **Sexual activities (erection, ejaculation, copula, ovulation, uterine activity and premature delivery).** ## Amygdala - processing learned emotional responses - **Classical fear conditioning** - **Blood pressure (mmHg)** - **Cessation of movement (sec)** ## Sensory thalamus - **fast response before the detailed information provided by the cortex** ## Limbic System - **Function of "Reward" and "Punishment"** - **Checks whether the sensations are pleasant or unpleasant (reward or punishment)** - **Affective nature of sensations** - **Electrical stimulation of certain limbic areas:** - **pleasure - reward** - **provokes terror, pain, fear, defense, flight reactions - punishment** - **The degrees of stimulation of these two opposing systems affect behavior.** ## Reward centers - **Major reward centers = pathway of the medial forebrain bundle, lateral and ventromedial nucleus of the hypothalamus.** - **Secondary reward centers = amygdala, septum, certain areas of thalamus and basal ganglia** ## Punishment centers - **Major punishment centers = central gray area around the aqueduct of Sylvius in the midbrain, periventricular zone of the hypothalamus and thalamus.** - **Secondary punishment centers = amygdala and hippocampus.** - **Stimulation of the punishment centers inhibits the frequency of pleasure responses in the reward centers, demonstrating that punishment/fear takes precedence over reward/pleasure.** ## Punishment Centers: Anger pattern - **Stimulation of punishment centers of the hypothalamus ( periventricular zone and lateral hypothalamus) and other limbic structures = anger pattern** - **it is inhibited by signals from reward centers - ventromedial nucleus of the hypothalamus : placidity and meekness.** ## Importance of reward or punishment in behavior - **Effect of tranquilizers (eg chlorpromazine) inhibits both punishment and reward centers, thus decreasing affective reactivity.** ## Importance of reward or punishment in learning and memory - Habituation vs Reinforcement - **A new sensory stimulus always stimulates several areas of the cerebral cortex → emotional response.** - **Sensory experience that causes neither reward nor punishment is poorly remembered.** ## Importance of reward or punishment in learning and memory - Habituation vs Reinforcement - **If the stimulus causes reward or punishment rather than indifference, the cerebral cortical response becomes progressively more intense during repeated stimulation and the response is reinforced - reinforcement.** - **The repetition of the same stimulus leads to the almost complete extinction of the emotional response - habituation, the individual ignores the stimulus.** ## Functions of the Hippocampus - **Sensory experience → hippocampus activation** - **Stimulation of different areas of the hippocampus can cause different behavioral patterns (eg pleasure, anger or excessive sexual desire).** - **Hippocampus can become hyperexcitable** - **Epileptic seizures : miscellaneous psychomotor effects, including olfactory, auditory, visual, tactile, and other types of hallucinations that cannot be suppressed despite the individual recognizing that they are unreal** ## Hippocampus: role in learning - **Bilateral removal of Hippocampus (e.g. treatment for epilepsy) → anterograde amnesia:** - **People recall previous memories satisfactorily but they do not learn new information based on verbal symbolism.** - **They are capable of short-term memory of up to a minute, although their ability to establish memories lasting longer than a few minutes is completely or almost completely abolished.** ## Animal Body Function VII **REFERENCES** **November 22, 2023** **Nataniel Rosa, DVM, MVSC** **[email protected]** ## Nervous System **Nataniel Rosa, DVM, MVSc** **[email protected]** ## Thank you! ## Good study **Nataniel Rosa, DVM, MVSc** **[email protected]**