2024 Student Thalamus and Hypothalamus PDF

EX AM 3 BREAKDOWN OF C ONTENTS Friday, November 15th at 10:00 AM 40 or 42 questions (80 minutes) 1. 16 questions from Dr. Joy 2. 16 questions from Dr. Nguyen 3. 8 or10 questions fill-in-the-blank images from lab DIENCEPHALON (AND OTHER STRUCTURES) Vuvi H. Nguyen MS, P...

EX AM 3 BREAKDOWN OF C ONTENTS Friday, November 15th at 10:00 AM 40 or 42 questions (80 minutes) 1. 16 questions from Dr. Joy 2. 16 questions from Dr. Nguyen 3. 8 or10 questions fill-in-the-blank images from lab DIENCEPHALON (AND OTHER STRUCTURES) Vuvi H. Nguyen MS, PhD Dept of Diagnostic and Biomedical Sciences UTHealth Houston School of Dentistry  LEARNING OBJEC TIVES Name the components of the diencephalon. Describe the anatomical boundaries of the thalamus and hypothalamus. List the functions of the thalamus and hypothalamus. Define the functions of the nuclei in the thalamus and hypothalamus. Explain the clinical manifestations when specific nuclei are lesion/ damaged. Describe the function of the pituitary gland. Compare and contrast the anatomical relationship of the anterior and posterior lobes of the pituitary gland to the hypothalamus. Explain the importance of The Papez Circuit and its players.  DIENCEPHALON Lies deep beneath the cerebrum and comprises primarily of the thalamus, hypothalamus, and epithalamus (pineal gland), which together define the walls of the 3rd ventricle. Connection between the cerebrum and the rest of the nervous system- brain, spinal cord, and PNS which all send information to the cerebrum through the diencephalon. The one exception- olfactory system which connects directly with the cerebrum. The thalami are two elongated, ovoid structures on either side of the midline that make contact in the middle. The hypothalamus is inferior and anterior to the thalamus, culminating in a sharp angle to which the pituitary gland is attached. The epithalamus is located posterior to the thalamus.  EPITHALAMUS Consists of the pineal gland (endocrine) and habenula (connects limbic system to midbrain) Pineal gland Midline, unpaired structure, located just rostral to the superior colliculi Synthesize melatonin (hormone that regulates the body sleep- wake cycle (responds to darkness) Helps with timing body’s circadian rhythm (24-hour internal clock) Habenular nuclei Located just anterior to the pineal gland as small swellings in the stalk of the pineal gland Respond to olfactory stimulation and involved in emotional and visceral responses to odors.  THALAMUS Largest subcortical (egg-shaped) grey matter of CNS- main constituent of the diencephalon Known as a relay station of all incoming motor (movement) and sensory information (hearing, taste, sight, and touch but not smell) from your body to your brain. Smell is the only sense that actually bypasses this thalamus. And instead, it has its own private relay station that, when it comes from the nose, it goes to a certain area in the brain. BIG PICTURE: All information must first past through the thalamus before being routed to its destination- the cerebral cortex- for further processing and interpretation. Recall: The spinothalamic tract is a sensory pathway arising in the spinal cord. It sends information to the thalamus about temperature, pain, itch, and crude touch.  BOUNDARIES OF THE THALAMUS Anteriorly: interventricular foramen Posteriorly: pineal gland and superior colliculus Medially: third ventricle- see massa intermedia (interthalamic adhesion) which connect the two halves of thalamus. Superiorly: body of the lateral ventricle Inferiorly: hypothalamic sulcus (separates the thalamus from the hypothalamus) Hypothalamic sulcus  THALAMUS- FUNCTIONS Relaying sensory information- take in information from all of your senses (tase, touch, hearing, seeing), except smell, into your brain. Each sensory function has a thalamic nucleus that receives, processes, and transmits the information to its related area within the cerebral cortex. Relaying motor information- similar to sensory info., motor pathways all pass through the thalamus. Prioritizing attention- helps decides what to focus on among the vast info that it receives Role in consciousness- keeps you awake and alert Role in thinking (cognition) and memory- connected with the limbic system which is involved in processing and regulating emotions, formation and storage of memories, sexual arousal and learning. The thalamus also contributes to perception and plays a role in sleep and wakefulness.  HOW DOES THE THALAMUS WORK? Sensory information travel along nerve fibers from the body through various brain structures to reach the thalamus. Specialized regions within the thalamus, called nuclei (nerve cell bodies), each process specific sensory or motor impulses received from the body and then relay the selected information to the corresponding area in the cerebral cortex for interpretation.  THALAMUS- GENERAL LAYOUT OF NUCLEI A Y-shaped layer of white matter called the internal medullary lamina divides the thalamus into 3 main groups of nuclei: the anterior, medial, and lateral groups based on their relative position. The internal medullary lamina contains afferent and efferent thalamic fibers that enter or leave the thalamic subnuclei The external medullary lamina (white matter) covers the lateral surface of the thalamus.  THALAMUS- ANTERIOR GROUP OF NUCLEI LIMBIC NUCLEI Smallest thalamic nuclear group that lies between the bifurcation of internal medullary lamina (IML) Consists of 3 subnuclei- the anteroventral (AV), anteromedial (AM), and anterodorsal (AD)→ collectively refered to as the anterior nuclei of the thalamus. Anterior nucleus- Functions- expression of emotions, learning, memory, behavior regulation. Reciprocal connections with the hypothalamus and limbic system.  THALAMUS- MEDIAL NUC LEAR GROUP LIMBIC NUCLEI Resides medial to the internal medullary lamina, which separates it from the anterior and lateral nuclear group. Includes the more prominent dorsomedial nucleus (DM)- next to the interthalamic adhesion. Function in emotional behavior and memory; attention, organization, planning, and higher cognitive thinking. Projects to the prefrontal cortex and limbic system.  THALAMUS- LATERAL NUCLEAR GROUP Consists of numerous subnuclei that collectively form the largest nuclear group of the thalamus. Arranged into 2 step-like rows, the dorsal and ventral tiers of nuclei (subnuclei).  THALAMUS- LATERAL NUCLEAR GROUP- DORSAL TIER MULTIMODAL NUCLEI Composed of the lateral dorsal nucleus (LD), lateral posterior nucleus (LP), and the pulvinar nucleus (P). Have connections with the association areas in the parietal lobe, temporal lobe, occipital lobe, and with the cingulate gyrus.  THALAMUS- LATERAL NUCLEAR GROUP- DORSAL TIER Lateral dorsal (LD) nucleus- primarily involved with integrating visual signals from the occipital cortex Lateral posterior (LP) nucleus- plays a role in integrating and modulating visual, somatosensory, and motor signals (processing visual info). Pulvinar (P) nucleus- sits at the posterior end of the thalamus and is the most prominent nucleus; functions in the integration of visual, auditory, and somatosensory info. With the exception of the lateral dorsal nucleus, these nuclei are connected with the association areas of the cerebral cortex, and function in the integration of sensory input.  THALAMUS- LATERAL NUCLEAR GROUP- VENTRAL TIER Includes the ventral anterior (VA) nucleus, ventral lateral (VL) nucleus, and ventral posterior (VP) nucleus. The ventral posterior nucleus is further subdivided into the ventral posterior medial (VPM) nucleus and ventral posterior lateral (VPL) nucleus. Ventral tier also includes the medial and lateral geniculate nuclei (MGN and LGN respectively) or bodies.  THALAMUS- LATERAL NUCLEAR GROUP- VENTRAL TIER MOTOR NUCLEI Ventral anterior (VA) nucleus- primarily involved in planning and initiating movement by receiving input from the basal ganglia and sending projections to the premotor cortex (involved in selection of appropriate motor plans for voluntary movements) Ventral lateral (VL) nucleus- acts as a central hub for motor control, receiving inputs from the cerebellum and striatum, and projecting to the primary motor cortex (involved in the execution of voluntary movements)  THALAMU S- LATE RAL NUC LEAR GROU P- VENTRAL TIER SENSORY NUCLEI Ventral posterior (VP) nucleus- relays processed sensory info to the postcentral gyrus (somatosensory cortex) of the parietal lobe. Subdivided into the ventral posterior medial (VPM) nucleus and the ventral posterior lateral (VPL) nucleus. VPM- relay general somatic afferent information (touch, pressure, pain and temperature sensation, and proprioception) from the orofacial region, and special visceral afferent sensation (taste) VPL- relays pain and temperature sensation from the body, terminals of the medial lemniscus transmitting discriminatory (fine) touch, pressure, joint movement, and vibratory sensation from the body (recall DCML pathway) and terminals from the anterior spinothalamic tract relaying light (crude) touch sensation from the body).  THALAMUS- METATHALAMIC NUC LEI SENSORY NUCLEI Includes the medial and lateral geniculate nuclei. Two oval shaped elevations located inferior to the pulvinar of the right and left sides. Both sensory nucleus Medial geniculate nucleus (MGN) processes auditory input from both ears. Projects to the auditory cortex (temporal lobe). Lateral geniculate nuclei (LGN) processes visual input from both eyes. Projects to the visual cortex (occipital lobe).  THALAMUS- CONDITIONS AND DISORDERS Dysfunction is typically caused by stroke, migraine, metabolic disease, brain infection, injury or tumor. Signs and symptoms of thalamic disorders vary and can include: Memory loss, and confusion, aphasia (VERY RARE- both in speaking and understanding language), apathy, trouble with attention (loss of alertness), trouble processing sensory info., impaired movement (tremors), vision problems, thalamic syndrome (tingling and burning pain), weakness on one side of body,  THALAMUS- CLINIC AL COMMENTS Sensory Loss usually results from thrombosis of one of the arteries supplying the thalamus damage to the VPM and VPL nuclei → loss of all form of sensation, including light touch, tactile localization and discrimination, and muscle joint sense from the opposite side of the body Thalamic Syndrome (may occur as patient is developing from a thalamic infarct) The body becomes hypersensitive to pain because of damage to the thalamus. (e.g. heat, cold, or stress can make the pain worse).  HYPOTHALAMUS Sits inferior and anterior to the thalamus Attached to the pituitary gland by a stalk called the infundibulum Despite its small size, it is the command center for all autonomic functions in the body.  HYPOTHALAMU S- BOUNDARIES Hypothalamic sulcus border Anteriorly: lamina terminalis (terminal layer- Lamina terminalis border makes up the ant. wall of 3rd ventricle) Posteriorly: Mammillary bodies (functions in learning and memory) Inferiorly: optic chiasm to mammillary bodies Superiorly- hypothalamic sulcus Optic chiasm Mammillary body border Infundibulum border Pituitary feature  HYPOTHALAMUS- FUNCTIONS Numerous functions that are crucial for survival- maintains homeostasis, control of appetite, fluid balance, electrolyte balance, glucose concentration, metabolism, circadian rhythm, and body temperature regulation. Works with the hippocampus to form new memories. Associated with reproduction of species (sexual behavior) by integrating the functions of the endocrine, autonomic (visceral motor), somatic motor, and limbic systems. Consists of collection of nuclei (nerve cell bodies) that each play a role in one or more of the above functions. Pituitary gland (known as hypophysis)- pea-sized gland located at the base of the brain below the hypothalamus and has 2 lobes- anterior lobe (adenohypophysis) and posterior lobe (neurohypophysis). Functions of each lobe is to secrete different hormones in response to signals from the hypothalamus. The pituitary is connected to the hypothalamus through a stalk of blood vessels and nerves called the pituitary stalk (infundibulum) There is a special venous system between the hypothalamus and the anterior pituitary called the pituitary portal system (known as the hypothalamic- hypophyseal portal system).  ANTE RIOR PITUITARY: HYPOTHALAMO-HYPOPHYSEAL PORTAL SYSTEM The infundibulum contains a bridge of capillaries that connects the hypothalamus to the anterior pituitary. Network- hypophyseal portal system- allows hypothalamic hormones to be transported to the anterior pituitary without becoming diluted in systemic circulation. Blood from the 1st capillary bed supplies a secondary capillary plexus via hypophyseal portal veins. BIG PICTURE: Function to transport hypothalamic factors (hormones) from the hypothalamus to the pituitary gland, where they stimulate or inhibit the release of hormones into the blood stream. This process helps maintain homeostasis.  ANTE RIOR PITUITARY: HYPOTHALAMO-HYPOPHYSEAL PORTAL SYSTEM There are 2 types of these chemicals: Releasing factors→ causes the anterior pituitary to release hormones Inhibiting factors→ prevent the release of anterior pituitary hormones until it is time to release again. Then the hypothalamus stops sending inhibiting factors and hormones are released into the blood. Feedback: hormones that have been released into the blood travel to the hypothalamus and “tell” the hypothalamus when to stop causing release of these hormones Arcuate (infundibular) nucleus (from the hypothalamus)- delivers A network of blood vessels that connects the hypothalamus peptides to the anterior pituitary via this portal system. and the pituitary gland, allowing hormones to travel between the two glands  The hypothalamus controls the anterior lobe of the pituitary with releasing factors and inhibiting factors: Releasing and inhib iting ho rmones The anterior pituitary produces 7 hormones: Growth hormone (GH) Thyroid-stimulated hormone (TSH) Adenocorticotrophic hormone (ACTH) Follicle-stimulating hormone (FSH) Luteinizing hormone (LH) Beta endorphin Prolactin Prolactin (PRL) promotes lactation in women. After birth, it stimulates the mammary glands to produce breast milk. The effects of prolactin depend heavily upon permissive effects of estrogen, progesterone, and other hormones. The let-down of milk occurs in response to stimulation from oxytocin. In a non-pregnant woman, prolactin secretion is inhibited by prolactin-inhibiting hormone (PIH), which is actually the neurotransmitter dopamine, released from neurons in the hypothalamus. Only during pregnancy do prolactin levels rise Feedback circuit primarily in response to a decrease in inhibition by PIH and partially due to stimulation by prolactin-releasing hormone (PRH) from the hypothalamus.  POSTERIOR PITUITARY GLAND Different mechanism compared to the anterior pituitary The posterior pituitary is connected to the hypothalamus by a bridge of nerve axons called the hypothalamic- hypophyseal tract (in contrast to the anterior pituitary which is connected to the hypothalamus by vasculature) In the hypothalamus, there are 2 nuclei called the paraventricular and supraoptic nuclei. The posterior pituitary is actually an extension of the neurons of the paraventricular and supraoptic nuclei. The posterior pituitary gland does not produce hormones, but rather stores and secretes hormones produced by the hypothalamus. Neurons of the paraventricular nucleus produce the hormone oxytocin. Neurons of the supraoptic nucleus produce ADH. These hormones travel along the axons into the axon terminals within the posterior pituitary. In response to the action potentials, these hormones are released from vesicles within the axon terminals into the bloodstream.  HYPOTHALAMU S Nuclei organized in 3 groups: Anterior group synthesizes hormones released from the posterior lobe of the pituitary gland and consist of the: Preoptic nucleus, paraventricular nucleus, and supraoptic nucleus (as well as anterior nucleus and suprachiasmatic nucleus- not shown) Middle (tuberal) group controls hormones release from the anterior lobe of the pituitary gland and consists of: Dorsomedial nucleus, ventromedial nucleus, and arcuate (tuberal) nuclei Posterior (mammillary) group activates the sympathetic nervous system and consist of: Posterior nucleus Mammillary nuclei (located in mammillary bodies) Nuclei in right hypothalamus (midsagittal section) Anterior region: HYPOTHALAMIC NU CLEI ▪ SC- suprachiasmatic ▪ SO- supraoptic ▪ Pr- preoptic ▪ An- anterior ▪ PV-paraventricular Middle region: ▪ DM-dorsomedial ▪ VM-ventromedial ▪ Ar-arcuate Posterior region ▪ Po-posterior ▪ MB- Mammillary body ▪ L-lateral ▪ Inf- Infundibulum ▪ AC- anterior commissure 33  HYPOTHALAMIC NU CLEI- ANTERIOR GROUP 1. Preoptic nucleus- regulates the release of gonadotrophic hormones (produces testosterone, progesterone, estrogen) from anterior pituitary gland 2. Supraoptic nucleus synthesizes oxytocin and vasopressin (ADH)- made by the posterior pituitary gland 3. Paraventricular nucleus (both hormones are stored and released as needed) Vasopressin- antidiuretic function= increases absorption of water in the kidneys Conservation of water. Lesion of the supraoptic nucleus and paraventricular nucleus results in diabetes insipidus (patient passes out large volume of urine (polyuria) and drinks large quantities of fluid due to thirst (polydipsia). Oxytocin- stimulate smooth muscle contractions (uterus) during labor and stimulate the ejection of milk (letdown) during lactation; promotes feeling of bonding between mother and child known as attachment. Also involved in feelings of love and closeness, as well as in sexual response.  HYPOTHALAMIC NU CLEI- ANTERIOR GROUP 4. Anterior nucleus- controls parasympathetic system and functions in thermoregulation (cooling) of the body. Damage leads to hyperthermia (body’s overheating). 5. Suprachiasmatic nucleus- receives direct input from retina. Controls circadian rhythm- body’s internal clock (regulation of our daily rhythm of eating, sleeping, defecating, periods of activity). Light sets the circadian clock. Melatonin is secreted by the pineal gland and secretion increases at night.  HYPOTHALAMIC NUCLEI- CONTROL OF APPETITE Hypothalamic control of appetite by 2 structures in the hypothalamus 1. Ventromedial nucleus (middle region)- “satiety center-” that tells the body when it has enough to eat. When food has been eaten→ blood sugar levels high→ ventromedial hypothalamus is stimulated→ “full”. Lesioning causes abnormal food intake to point of obesity. 2. Dorsolateral nucleus (located in the lateral hypothalamus)- “appetite (hunger/ thirst) center”- tells the body when to eat. When the blood sugar level drops to low levels, the dorsolateral hypothalamus is stimulated→ tells the body it is hungry→ causes food seeking and eating. Lesions leads to anorexia and starvation. HYPOTHALAMIC CONTROL OF APPETITE by two structures in the hypothalamus Appetite or Hunger center in dorsolateral hypothalamus Satiety center Hypothalamic control of appetite. 37  THE HYPOTHALAMU S AND EMOTION In humans, lesions have produced clinical symptoms The emotion of anger stimulation 1. rage and fear of the dorsomedial nucleus 2. happiness and sadness (very hard to draw conclusions of that range of causes a cat to demonstrate signs 3. apathy and excitement emotions in terms of the anatomy involved.) of rage: snarling, spitting, scratching, back arching, hair THE HYPOTHALAMUS AND ANGER erection. This is called sham rage because it disappears as soon as Anger center: dorsomedial nucleus the stimulating current is shut off. Lesioning of the ventromedial nucleus also causes sham rage. This is also the satiety center, so the cat overeats as well. Angry fat cat→ SHAM RAGE  HYPOTHALAMIC NU CLEI- POSTERIOR REGION 1. Posterior nucleus- controls sympathetic system; regulates temperature (response to cold). Causes vasoconstriction so that blood is moving from the surface where it will release heat into the interior body. Causes things to happen to raise the body temperature- e.g. shivering (body heat conservation). Damage to this nuclei causes hypothermia. 2. Mammillary nucleus- projects to the anterior nucleus of the thalamus via the mammillothalamic tract (seen in the Papez Circuit); involved in the control of various reflexes associated with feeding as well as mechanisms relating to learning and memory formation. savage behavior.  REVIEW OF FUNCTIONS 1. Eating Two nuclei plays role – a. Lateral hypothalamic nuclei- “hunger” center -tonically active “hunger” center in the lateral hypothalamus → evokes eating behavior -damage to the “hunger” center → anorexia and severe loss of body weight b. Ventromedial nucleus – “satiety” center -stops hunger and inhibits the “hunger” center when a high glucose level is reached after food intake -lesions of the “satiety” center → hyperphagia (feeling of insatiable hunger) and obesity 2. Autonomic Function a. Posterior nucleus – controls sympathetic nervous system b. Anterior nucleus – controls parasympathetic system; 3. Body Temperature a. Anterior nucleus (in anterior hypothalamus) -regulates temperature (response to heat)→heat loss center/ cooling -rise in body temperature → sweating and vasodilation in skin; panting in non-humans -Destruction causes hyperthermia (body overheats) 41  REVIEW OF FUNCTIONS Body Temperature Cont. b. Posterior nucleus (in posterior hypothalamus) -regulates temperature (response to cold)→ “heat production center”; shivering; vasoconstriction of peripheral vessels. -Destruction causes hypothermia (dangerously low body temp.) 4. Water Balance (Vasopressin helps kidneys reabsorb water from urine, which controls the amount of water lost by the body). a. Vasopressin (ADH) release from the posterior pituitary → activated by chemoreceptors within a “thirst” center located near the supraoptic nucleus b. pain, stress, and certain emotional states also stimulate vasopressin secretion c. ADH controls water excretion by the kidneys. 5. Anterior Pituitary Function a. Direct influence on secretions of the anterior pituitary and indirect influence on the secretion of other endocrine glands by releasing or inhibiting hormones via the hypothalamo-hypophyseal portal system b. Regulates many endocrine functions, including reproduction, sexual behavior, thyroid and adrenal cortex secretions, and growth 42  REVIEW OF FUNCTIONS 6. Circadian Rhythm -Suprachiasmatic nucleus→ “intrinsic clock” -controls circadian rhythms. -lesions in this nucleus → loss of all circadian cycles 7. Expression of Emotion -Involved in the expression of rage, fear, aversion, sexual behavior, and pleasure -Patterns of expression and behavior → subject to limbic system influence and, in part, to changes in visceral system function Physiologically, there is hardly any activity in the body that is not influenced by the hypothalamus. 43  LIMBIC SYSTEM Group of interconnected structures in the brain that regulates emotions, behaviors, motivation, and memory. One of the oldest structures of the brain- produces natural instincts use to survive- feeding, reproduce, care for young, and react to surroundings (fight or flight response) Note: In the context of limbic function, emotion does not refer to “happy” or “sad”, but rather drinking when thirsty or a response to a potential mate. (Think behaviors needed for survival.)  LIMBIC SYSTEM “Limbic” comes from the Latin word “limbus” which means “border”- components sit on the border above the brainstem and underneath the cerebral cortex. Four main structures of the limbic system: Thalamus Hypothalamus Amygdala Thalamus- sensory relay station for sight, sound, taste, and touch and Hippocampus the thalamus directs these senses to the cortex. Emotion is very contingent on the things that you see, touch, and hear. Hypothalamus- regulates homeostasis. In charge of the ANS (fight/flight and rest/digest in terms of emotion).  AMYGDALA Greek word for “almond” (hence its size/shape) Paired structures inside the temporal lobe. Part of the limbic system whose main role is to detect danger (“fear reactivity”) as well as play a role in behavior, emotional control, and learning. Sits near structures that carry information from your sense especially smell (scents connect strongly to emotions and memories) Also connects to brain areas that process vision and hearing.  NEUROANATOMIC AL POSITION OF AMYGDALA If the brain is turned upside down the end of the structure continuous with the hippocampus is called the uncus. If you peel away uncus (means hook) you will expose the amygdala which is next to the anterior end of the hippocampus. Similar to the hippocampus, major pathways communicate bidirectionally and contain both efferent and afferent fibers.  AMYGDALA Sometimes called the “aggression center” and experiments have shown if stimulated, produce feelings of anger and violence as well as fear and anxiety. Kluver- Bucy syndrome involves bilateral lesions to the left and right amygdala (VERY RARE)→ disinhibition of emotions and impulses: Hypersexuality Hyperorality- putting many things in mouth (exploring the environment with their mouth) Disinhibited behavior- doing reckless things because you don’t consider risks. Ignore social conventions. Act impulsively- No more fear.  HIPPOC AMPUS- FUNCTIONS Responsible for memory and learning Converts short-term into long-term memories by organizing, storing, and retrieving memories within Right and left the brain. hippocampi sits in Visual-special memory (remembering the position of the temporal lobe. your body in relation to nearby objects) Verbal memory- remembering the right words to say. Declarative (or explicit) memory- the recollection of facts or experiences  HIPPOC AMPUS Works with the amygdala to connect memories to emotions, which generate an emotional response. Hippocampus is connected to the hypothalamus and amygdala which help regulate various bodily functions (e.g. “fight-or flight”) Imagine you see a dog for the first time. The dog wags its tail and licks your hand when it sees you.Your amygdala and hippocampus work together to store that memory in your brain, so the next time you see a dog, you remember your past experience and feel calm and happy to see the animal.  HIPPOC AMPUS If the hippocampus is damaged, difficulty in forming new memories- experiences fades away While new memories can’t be formed, old memories are still intact. Therefore long term memories function just fine. -------------------------------------------------------- Amnesia- uncommon on its own but very common symptoms of certain conditions (e.g. Alzheimer’s disease) Anterograde amnesia- can’t form new memories but can remember things before the amnesia. Retrograde amnesia- can’t recall memories from your past.  HIPPOC AMPUS- THE PAPEZ CIRC UIT 1937- Anatomist James Papez described a neural circuit for the control of cortical emotions. Believed to be the major pathway for storing memory. Shows that neural pathways connect the hippocampus with the limbic system, indicating that memories that are stored from the hippocampus have a heavy emotional content. (Explains why we tend to remember happy or sad moments of life more readily than ‘routine’ everyday events. Also explains why some memories also tend to cause autonomic effects)  HIPPOC AMPUS- THE PAPEZ CIRC UIT Loop involving several subcortical structures that are involved in memory and emotions. Information from the hippocampus projects via fornix to mamillary bodies then to the anterior nucleus of the thalamus via mammillothalamic tract, which in turn projects to the cingulate gyrus, and then back to the hippocampus. Lesions of the Papez circuit occur in alcoholics Processes emotion and with Vitamin B1 deficiency- mammillary bodies (recollective behavior regulation. Regulates autonomic are affected→ amnesia (forgetfulness) syndrome memory) motor function.) called Korsakoff’s psychosis (characterized by confusion, disorientation, inability to store new info- anterograde amnesia). ANY QUESTIONS?