NSCI 110 1st Edition Lecture 32 Outline of Last Lecture I The limbic system and hypothalamus allow us to make correlations with sensory stimuli and emotions a Axons project to hypothalamus or periaqueductal gray II Neurochemical compounds increase the odds of a certain behavior being produced a Dopamine and norepinephrine release induces aggressive behaviors b Originate in structures of the midbrain III There are genetic predispositions that give rise to more aggressive tendencies a Altered serotonin signaling b Gonad hormone secretions IV Emotion is our cognitive interpretations of subjective feelings a Relies on motivation b Mediated by the hypothalamus limbic system frontal lobes V Chemosignals are essential in mediating species specific behaviors a Mate recognition sexual behaviors maternal aggression b Olfactory function is crucial in discriminating between certain stimuli Outline of Current Lecture I The main olfactory system is responsible for detecting common odorants a Projects to olfactory bulb then pyriform cortex or amygdala II The accessory olfactory system is responsible for detecting pheromones a Projects to accessory olfactory bulb from vomeronasal organ b Extends to amygdala and hypothalamus c Involved in reproductive and sociosexual behaviors III There are five different receptor types giving rise to sweet salty sour bitter and umami taste sensations a Relayed from taste cells on the tongue to solitary tract b Projections to insula or hypothalamus and orbitofrontal cortex IV Innate releasing mechanisms are stereotypes actions that are induced by specific stimuli Current Lecture Much convergence onto a single glomeruli from multiple receptors o Hypotheses spatial or temporal differences among these adjacent receptors gives rise to different perceptions of odors high acuity Olfactory bulb projects to the pyriform and entorhinal cortex or amygdala no thalamic relay o Then to the thalamus and orbitofrontal cortex or hypothalamus Social emotional and eating behaviors These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o Only sensory system that does not have to pass through the thalamus to successfully relay information Accessory olfactory system o Pheromones are chemosignals released by one animal that affects the behavior of another individual of the same species o Detected by the vomeronasal organ that connects to the amygdala and hypothalamus o Cats raise upper lips to close off nasal passages to allow more passage of the odorants to the VNO o VNO in humans Vestigial Nonfunctional genes Human olfactory processing o Behaviorally relevant smells Odors self kin vs non kin friend vs stranger Body odors activate brain regions for emotion mostly subconscious Identifying the causes of behavior o Circuit activity depends on hormones and chemical senses smell and taste Taste gustation GUSTATION Differences in threshold and preferences o Receptor numbers decline with age by age 20 50 lost o Children have the highest preference for sweets lowest for bitter compounds Genetic predispositions Each of the five types respond to different chemical components o Sweet sour salty bitter umami MSG glutamate containing compounds o Receptors on the tongue sides of cheeks top of mouth near throat Receptors are distributed throughout in different densities and sensitivities o Hydrogen ion release from compounds gives a sour acidic taste Sodium ions give a salty taste Minty gives a cool sensation and spicy gives a hot sensation o Cranial nerves 7 9 and 10 project to the nucleus of the solitary tract Gustatory pathways o Cranial nerves nucleus of solitary tract in the pons o One pathway projects to the VMP of the thalamus to the insula primary gustatory cortex o Other pathway projects to the lateral hypothalamus Motivation behind eating behaviors Can also travel to the amygdala in this pathway Pleasantness and emotional salience of food o Flavor type intensity orbitofrontal cortex Olfactory and gustatory input give rise to flavors Right side is more active in perceiving pleasantness left side in perceiving disgust EVOLUTIONARY INFLUENCES ON BEHAVIOR Innate releasing mechanism IRM o Specific sensory stimuli stereotyped action o Modified with experience BF Skinner o Many behaviors are learned o Reinforce event that strengthens the behavior that it follows o Experience shapes behavior by pairing stimuli and reinforcers
View Full Document
Unlocking...