MCB 462January 20, 2016Lecturer: Rhanor Gillette THE BIOLOGY OF BEHAVIORBUILDING AN ANIMALWhat are animals designed to do? The most basic functions of organisms can pretty well be listed under three main headings:Acquistion of resources: Nutrient acquisition and conversion of nutrients to body mass, hydration, shelter, $, etc.Defense: Avoidance of injury and excessive waste of energy. Defense against macro- and micropredators.Reproduction: Replication of the organism’s genes in a new generation. Courtship, brooding of offspring.Most aspects of animal behavior and physiology serve these functions. Supporting above functions, the following are the diverse critical physiological functions that the brain coordinates in most larger active animals:o Homeostasis (regulating physiological parameters around some optimizing value)- Thermoregulation – regulating body temperature through internal heat generation (mammals, large pelagic fish like some sharks and tuna) or behavior (basking in the sun like lizards, putting on a sweater or taking it off, etc.)- Osmoregulation – regulating body salt content and water balance (drinking behavior, kidney function).- Circulation – carrying nutrients and O2 to tissues, flushing thewastes, like CO2 and NH3. Controlling capillary function.- Respiration – regulation of respiratory surfaces (lungs, gills, and in some cases, skin for gas exchange (O2/CO2)o Reproduction – courtship, mating, parturition and care of the young (or not).o Nutrition – getting a meal and digesting itLater, we will examine the integration of these functions in the mammalian brain.Here, right now, because it is so important in all facets of animal behavior, let’s arrive at a basic understanding of decision in animal (and plant) behavior. In general, decisions to prefer one behavioral choice over another are based on cost-benefit calculations. Animals make these cost-benefit calculations by integrating 1) sensation, 2) internal state, and 3) memory of experience. (probably on the test). The final integration of sensation, internal state and experience defines Appetitive State. Appetitive state is simply the set of goal-directed cravings (e.g., hunger, play, sex) and their relative strengths from moment-to-moment. Appetitive state is manifested in the configuration and excitation states of goal-directed brain circuits. How this happens will be discussed later in the semester.Beginning with behavior, there are seven areas to be developed in these first lectures. We will begin with definitions of behavior and the main factors that influence it.21. Behavior is definable as all observable muscular and secretory responses to changes in an animal's internal or external environment; i.e., movement or secretion.You may already appreciate that behavior emerges from the interactions of sensory activity with internal state, and experience. These interactions happen mostly in the central nervous system. Drive -- the long-term arousal level of a set of behaviors that normally act to accomplish nutritive (hunger), reproductive, maturational (e.g. play), and other functions that are basically important to the fitness of the organism.Motivation -- the level of arousal of a behavior or a set of behaviors that can be measured in response to stimulation.Examples in reproductive behavior of: - Seagulls- 3-spined stickleback fishIn males, Spring seasonal hormones induce red ventral coloration, aggression towards other males (with red ventral coloration) and nest-building behavior.- Brooding geeseSign stimuli and releasers. Sensory stimuli that can elicit specific behavior patterns. Visual releasers, pheromones, etc. Please read about and understand the captivity of Von Uexkull's tick. 3Feature detection. Perception of special features in the environment. Feature detection is the result of sensory computations in the nervous system that enhance the representation of specific aspects in the brain. For instance, the frog eye is unusually sensitive to small round objects that move like bugs. Complex feature detectors appear to be wired into our own brains that aid us in interpreting facial expressions, and recognizing and acquiring speech, for instance.Memory for Experience. Habituation, sensitization, and associative learning.2. Be able to distinguish between proximate cause (the immediate cause)and ultimate cause (the evolutionary cause) in behavior.Proximate: Including sensation (feature detection), motivation, and experience -- these are recurring themes in all behavior. Also, the wiring of sensory structures, integrative functions, cognitive functions, pattern generators, motor circuitry, and the structure and function of musculature. For example, humans may engage in sexual behavior because they have an internal drive and respond selectively to certain stimuli.Ultimate: Evolutionary influences selecting for behaviors. For example, humans engage in sexual behavior because their ancestors did and passed along this tendency with their genes. A prime example of natural selection. It is of central importance to realize that behavior evolves like other phenotypic traits. Recall that 1) evolution arises from changes in frequency of different genes in populations, and 2) the frequency of a gene increases when it increases the number of surviving offspring. Theability of an animal to pass on its genes is its fitness. Natural selection 4is operating so as to increase the number of animals carrying genes that lead successfully to adaptive behavior.3. Compare fixed (stereotyped) behaviors with non-fixed behaviors. Fixed: In very fixed behaviors, the patterns are largely generated centrally, with little sensory feedback. Such behaviors are sometimes referred to as fixed action patterns. Some examples are: Egg-retrieval in the gooseSwallowing Yawning. Ballistic movementsNon-fixed: In non-fixed types of behavior, the patterning is dependent on sensory feedback from environment (and muscles). This sensory information acts directly on motor networks and decision-making mechanisms in the central nervous system. The results (hopefully) allow the animal to interact adaptively with the environment.Examples: exploratory locomotion, shoe-tyingMixed behavior: Of course, most behavior is a mixture of centrally patterned movements that are directed by drives, organized by motivation, and fine-tuned by sensory inputs. One attractive concept, based on much