NSCI 110 1st Edition Lecture 31 Outline of Last Lecture I Pathways from the lateral spinathalamic tract extend to a Reticular formation and periaqueductal gray b Tectum c Amygdala d Hypothalamus II Visceral pain has the following characteristics a Wide variance of sensitivity b Weak pain and injury relationship c Is diffuse poorly localized d Exhibit exaggerated autonomic responses III The hypothalamus performs acute and chronic stress responses a Controls many preganglionic spinal cord neurons IV The Gate Theory of Pain claims that different sensory pathways compete for arousal and perception in response to a stimuli a Certain methods reduce our perception of pain by inhibiting nociceptive receptor pathways V Stimulation of the periaqueductal gray matter reduces perception of pain VI The vestibular system is responsible for orienting movements and controlling balance a Semicircular canals and otolith organs work together to help us perceive our body s position in space i Utricle and saccule VII The secondary somatosensory cortex receives input from the primary somatosensory cortex a Gives rise to dorsal and ventral streams in nearby cortical regions VIII Aggression has a neural basis in the periaqueductal gray and hypothalamus a There are numerous subcategories of aggressive behaviors Outline of Current 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 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 V a Relies on motivation b Mediated by the hypothalamus limbic system frontal lobes 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 Current Lecture Limbic system and hypothalamus o Provides affective qualities to sensory signals o Limbic structures project their axons directly or indirectly to the hypothalamus and PAG Modulates their functions May enhance or diminish aggression depending on exact size Neurochemical correlates o Permissive vs productive effects Do neurotransmitters cause behaviors They merely increase the odds of that behavior being produced o Dopamine and norepinephrine potentiate aggression Catecholamines that often secreted in times of stress Origin brainstem Locus coeruleus neurons release norepinephrine Ventral tegmental area neurons release dopamine Destination project widely especially to limbic system and hypothalamus o Locus coeruleus Two blue ish spots in the pons Genetic component of aggression o Selectively bred dogs exhibited altered serotonin 5 HT signaling Dorsal raphe is the primary source of 5 HT molecules More aggressive behavior o Knockout mice 5 HT18 receptor knockouts MAOAKO monoamine oxidase metabolizes 5 HT Both led to altered 5 HT signaling o Humans some of us have inherited allelic polymorphisms that cause low MAOA expression Less 5 HT transporter gene expression Less MAOA activity o Gonadal hormones sex matters Androgens and estrogens alter 5 HT receptor expression High testosterone lowers stress perception overall but it also increases responsiveness to social threats Oxytocin regulates maternal behaviors such as maternal aggression Depend on dam s level of anxiety Oxytocin sensitizes the amygdala EMOTION AND BEHAVIOR Emotion is our cognitive interpretations of subjective feelings Motivation is a behavior that seems purposeful goal directed o These two are heavily influenced by the hypothalamus limbic system and frontal lobes Identifying the causes of behavior o Sensory deprivation experiments white noise in dark room limbs wrapped up Why was this aversive The brain does not like a total lack of sensory input Brain circuits underlie seeking behavior rewards o Predatory aggression relatively low sympathetic activation and stress compared with other types of aggression o Circuit activity depends on Individual hormonal activity of the organism Chemical senses smell and taste Innate vs learned o Chemosignals have a central role in motivated and emotional behavior Identifying others o Olfaction responsible for odor detection to discriminate safe vs unsafe Olfactory pathways o Air born chemicals dissolve in the mucosa interact with cilia of olfactory receptors Nasal epithelium contain olfactory receptors that project cilia Interact with odorants o Metabotropic activation of G protein coupled receptors leads to opening of Na channels Influx of sodium ions and depolarization of membrane o Travel to glomerulus inside the olfactory bulb Connects with mitral cells that project to the pyriform cortex Pass in between bone before synapsing at the glomeruli