Intro to Brain&Behavior

Main functions of the brain
Click the card to flip 👆
1 / 27
Terms in this set (27)
Main functions of the brain
•senses the environment (sensation and perception)
•generates movements
•controls and regulates the body's internal settings, surroundings
•reproduction
•adaptation
•(information processing and generating behavior)
Sensation and perception
•detection and assimilation of environmental events (internal and external)
•approximately 1/2 of brain devoted to above
•specific areas specialized to different senses
•brain organized in modular and hierarchical manner
•visual regions = 33% of primate brain
Movement
2 kinds: voluntary and involuntary
•voluntary: moving arm
•involuntary: heart beating
•prefrontal cortex: planning
•premotor cortex: how it's going to be done
•motor cortex: execution (info to spinal chord)
•basal ganglia (everything passes thru) = initiation and termination
•cerebellum: coordinates movement, multiple actions at once, quickly timed movements (piano), motor learning (sports), sensitive to alcohol
•involves sensory input - you must feel it for it to happen (smoothness of movement)
Internal regulation
•specialized regions maintain constancy
•autonomic nervous system: neural control
•endocrine nervous system: maintains constancy thru hormonal mechanisms
•communication goes both ways (brain-body)
•cytokines: proteins released by cells to communicate
•hypothalamus: sensitive to cytokines, orchestrates changes
Reproduction
•behaviors related to brain, essential to survival of species
•sexual behavior regulated by specialized hormones (largely regulated by hypothalamus)
•many hormones configure circuits to organize brain towards gender identity
Adaptation
•most outstanding legacy of brain
•cells and circuits have ability to change as a function of experience (learning)
•change is necessary (survival benefit)
•neurons can change thru experience, you're not the same person you were 10 years ago
•Alzheimer's = inability of brain to learn, remember (neurons degenerate)
Mind-Body problem
•how can physical matter (brain) generate etherial mind (consciousness, emotion) when it's made of the same stuff as the rest of the body?
Dualism
(substance)
•mind and brain are fundamentally different and governed by different laws
•brain = physical organ, laws of matter and energy
•mind = nonsubstantial, etherial
•foundation of soul, many religions
Descartes
•believed that brain and body are both subject to mechanical devices
•mind able to reason (only humans)
•hydraulic model: fluid filled ventricals (animal spirits) = mechanical device
•nerves fill with fluid = limb movement
•interaction with pineal body (gland) - at top of brain = interface for mind/body connection
•actually produces melatonin
•why? middle of nowhere, not connected, close to ventrical system
Monism
•reality, for the most part, is a unified whole
•all aspects of nature can be described as a single concept/system
•no distinction between mind and brain
•one fundamental essence in the universe
Mentalism•only thing that truly exists is the mind, everything else is an illusion/construction of mind •berkely = two versions •subjective = material world is own dream/mind •objective = someone else's dream (god, etc.) •Kant = no dreams, reality = construction of mind •psyche = mind, entity once proposed to be source of human behavior, life and deathIdentity theory•all mental states are simply physical states in the brain, numerically identical to physical processes in the brain •patterns of neurons interacting •physical changes in brain and subjective experience are the same •(light = particle and wave)Eliminative materialism•biology/physical workings of mind = essence •don't study cognitive processes/subjective experience •not as useful, filled with error, misleading •want new technology to explain physical changes, no emotional involvement •behavior = nervous system •allows us to try and explain mental phenomenon thru scientific methodEvolution/Darwin's theory•gradual change in the frequency of physical and behavioral characteristics in a given population over time •adaptive traits increase in frequency, eventually become common of species •Darwin = evolution thru natural selection •origin of species = differential success in the reproduction of different characteristics (phenotypes) results from interaction between organisms and environment •Mendel = genes •Started as a diffused center. Slowly became more centralized at the head. Regions process specific environments. Has the ability to change.Implications of Darwin's theory•because all animal species are related, so must be their brains •so too must be their behavior •both brain and behavior evolved bit by bit in animals that evolved to greater complexityVariability(3 conditions) •a particular trait must have differences within a population •genes are responsible for mechanism •mutations responsible for variability (change, add, delete)Heritability•you need a means by which info can be passed down thru generationsEnvironmental selection•environment selects traits that confer adaptation (positive) long enough for them to surviveCentralization•neural activity became centralized at the head •you need a processor nearby to process sensory info with speed and accuracyEncephalization•large brain mass in proportion to total body mass •directly correlates to intelligence levelGrowth and plasticityGrowth: •under particular environmental circumstances, regions of the brain begin to process specific characteristics of that environment Plasticity: •brain has ability to change with experience •cells are very plastic, can form new connections, shut off old ones •ability to sculpt and change = brain's greatest legacyEvolution of brain and behavior•Brain cells and muscles are recent developments in the evolution of life on Earth. Because they evolved only once, in the animal kingdom, a similar basic pattern exists in the nervous systems of all animals •The nervous systems of some animal lineages have become more complex - first a nerve net, followed by a bilaterally symmetrical and segmented nervous system, a nervous system controlled by ganglia, and, eventually, a nervous system featuring a brain and spinal cord. •The evolutionary developments in chordates, including a crossed nervous system located at the back of the body, are closely related to the growth of the cerebral cortex and cerebellum, which become extensively folded as they increase in size.Evolution of human brain and behavior•The closest living relative of modern humans is the chimpanzee. •Modern humans evolved from a lineage that featured Australopithecus, Homo habilis, and Homo erectus, groups in which more than one species existed at the same time. •Homo sapiens, or modern humans, originated in Africa about 200,000 years ago and coexisted with other hominid species in Europe and Asia for most of that time. •Constant changes in the environment eliminate some animal species and create new opportunities for others to evolve. Among certain groups of animals, adaptations to these changes include an increase in brain size. •The large human brain evolved in response to a number of pressures and opportunities, including changes in climate, the appearance of new food resources to exploit, changes in skull anatomy, and neoteny. •Elaborate social groups = other kinds of selection pressure, could have spurred brain growth (sexual selection, language, cooperation, empathy)Australopithecus•one of our homonoid ancestors - four million years ago •one of first to walk upright •common ancestor gave rise to australopithecus lineage, one member gave rise to homo lineageEncephalization quotientJerison's quantitative measure of brain size obtained from ratio of actual brain size to expected brain size, according to principle of proper mass, for an animal of a particular body sizeRadiator hypothesis•selection for improved brain cooling thru increased blood circulation enabled brain to growNeotenyprocess in which maturation is delayed - adult retains infant characteristics •idea derived from observation that newly evolved species resemble young of ancestors