Central nucleus (CoA)oSensory info from basolateral amygdala projects to wide variety of regions in brainoInvolved in emotional responses (esp. aversive)Conditioned Emotional Response-Also known as cued-fear conditioning.-Mediated by central nucleus of the amygdala (CoA).Serotonin and Aggression-AggressionoConflict resolutionRules:Conducted primarily by displaysEscalation occurs graduallyClear cut termination signals-ViolenceoIntense physical interaction with an intent to do harm.-Stronger serotonergic tone seems to result in less aggression-5-HIAA correlated with impulsivity and aggressionoLow 5-HIAA (indicating low serotonin levels) associated with risk taking behavioroIn mice, social isolation decreases serotonin releaseIsolated males are more aggressiveTame foxes have higher serotonin levels in the brain.-Serotonin and Aggression in HumansoVentromedial prefrontal cortex (vmPFC)Inhibition of emotional behavior Receives strong serotonergic input
oLower serotonin may increase impulsivityViolence may be related to inability to inhibit attack behaviorChapter 11 Ingestive Behavior-Body fluid homeostasis and thirstoOsmotic (osmometric) thirstoHypovolemic (volumetric) thirstA satiety mechanism:Stops hunger or thirst due to adequate levels of nutrients or wateroFluid Compartments:The fluid portion of the body can be divided into several compartments.Water can move between compartments via osmosis.oPhysiologic Concentration of SaltPhysiologic concentration of salt = 0.9% or 154 mMAn isotonic solution of salt = 0.9%, a hypotonic one is < 0.9%, and a hypertonic one is > 0.9%.Thirst-How do we regulate the amount of water in the body?oThe simple answers:Get rid of it, if we have too much.Drink more, if we don’t have enough.oDouble Depletion Hypothesis:There are two types of thirst: (1) Osmotic (normovolemic and hypertonic) o Results from the dehydration of the intracellular fluid due to the extracellular fluid becoming hypertonic. o Blood volume does not change. (2) Volemic (hypovolemic and isotonic) o Results from a loss of both water and solute. o Blood volume decreases but the extracellular fluid is still isotonic. - Osmoreceptors
Posterior Pituitary - The neural peptides it can release are: o Oxytocin (OT) o Vasopressin (AVP) AKA antidiuretic hormone (ADH) Changes the permeability of the kidney tubule so water can be reabsorbed A pressor agent (causes vasoconstriction) Release of vasopressin is parallel to drinking. Diabetes Insipidus - Symptoms include excessive urination, low blood pressure (hypotension) and excessive drinking. o Caused by lack of vasopressin o Note that the common form of diabetes is called diabetes mellitus - In both types there is excessive drinking and urination, but in mellitus there’s also excessive eating.
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