Lecture 31 Outline of Last Lecture I. Pathways from the lateral spinathalamic tract extend to:a. Reticular formation and periaqueductal grayb. Tectumc. Amygdalad. HypothalamusII. Visceral pain has the following characteristics:a. Wide variance of sensitivityb. Weak pain and injury relationshipc. Is diffuse/poorly localizedd. Exhibit exaggerated autonomic responsesIII. The hypothalamus performs acute and chronic stress responsesa. Controls many preganglionic spinal cord neuronsIV. The Gate Theory of Pain claims that different sensory pathways compete for arousal and perception in response to a stimulia. Certain methods reduce our perception of pain by inhibiting nociceptive receptorpathwaysV. Stimulation of the periaqueductal gray matter reduces perception of painVI. The vestibular system is responsible for orienting movements and controlling balancea. Semicircular canals and otolith organs work together to help us perceive our body’s position in spacei. Utricle and sacculeVII. The secondary somatosensory cortex receives input from the primary somatosensory cortexa. Gives rise to dorsal and ventral streams in nearby cortical regionsVIII. Aggression has a neural basis in the periaqueductal gray and hypothalamusa. There are numerous subcategories of aggressive behaviorsOutline of Current Lecture I. The limbic system and hypothalamus allow us to make correlations with sensory stimuli and emotionsa. Axons project to hypothalamus or periaqueductal grayII. Neurochemical compounds increase the odds of a certain behavior being produceda. Dopamine and norepinephrine release induces aggressive behaviorsb. Originate in structures of the midbrainIII. There are genetic predispositions that give rise to more aggressive tendenciesa. Altered serotonin signaling b. Gonad hormone secretionsIV. Emotion is our cognitive interpretations of subjective feelingsThese 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. NSCI 110 1st Editiona. Relies on motivationb. Mediated by the hypothalamus, limbic system, frontal lobesV. Chemosignals are essential in mediating species-specific behaviorsa. Mate recognition, sexual behaviors, maternal aggressionb. Olfactory function is crucial in discriminating between certain stimuliCurrent Lecture- Limbic system and hypothalamuso Provides affective qualities to sensory signalso 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 correlateso Permissive vs productive effects Do neurotransmitters cause behaviors? They merely increase the odds of that behavior being producedo 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 hypothalamuso Locus coeruleus Two blue-ish spots in the pons- Genetic component of aggressiono Selectively bred dogs exhibited altered serotonin (5-HT) signaling  Dorsal raphe is the primary source of 5-HT molecules More aggressive behavioro Knockout mice  5-HT18 receptor knockouts MAOAKO (monoamine oxidase  metabolizes 5-HT) ^ Both led to altered 5-HT signalingo Humans  some of us have inherited allelic polymorphisms that cause low MAOA expression Less 5-HT transporter gene expression Less MAOA activityo 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 amygdalaEMOTION AND BEHAVIOR- Emotion is our cognitive interpretations of subjective feelings- Motivation is a behavior that seems purposeful/goal-directedo ^ These two are heavily influenced by the hypothalamus, limbic system, and frontal lobes- Identifying the causes of behavioro 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 aggressiono Circuit activity depends on: Individual hormonal activity of the organism Chemical senses (smell and taste)- Innate vs learnedo Chemosignals have a central role in motivated and emotional behavior Identifying otherso Olfaction responsible for odor detection to discriminate safe vs unsafe- Olfactory pathwayso Air-born chemicals dissolve in the mucosa, interact with cilia of olfactory receptors Nasal epithelium contain olfactory receptors that project cilia Interact with odorantso Metabotropic activation of G-protein coupled receptors leads to opening of Na+ channels Influx of sodium ions and depolarization of membraneo 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