© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 1 Biological Foundations of Behavior 3

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 2 Nervous System: Biological Control Center Brain – thinks, calculates, feels, and controls motivation Spinal cord –Bundle of long nerves running through spine –Connects brain to every part of body Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 3 Neurons: The Units of the Nervous System Neuron – individual nerve cell Parts of neurons –Cell body: central part of nerve cell; contains nucleus or cell’s control center –Dendrites: small branches extending from cell; receive messages from other neurons –Axons: small branches at other end of neuron; send messages to other neurons Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 4 Neurons: The Units of the Nervous System

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 5 Neural Transmission Neurons –Function like wires and batteries –Have sacs filled with fluid chemicals containing surrounded by a second type of chemical –Ions: positive or negative changed particles –Cell membrane semipermeable in normal resting state –Polarized when negative ions inside cell membrane and positive ions outside Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 6 Neural Transmission Neurons –Depolarization – positive ions enter membrane –All-or-none principle –Action potential –Myelin sheath Average thickness in females is greater May indicate females process certain information better than males Multiple sclerosis destroys myelin sheath Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 7 Neural Transmission

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 8 Neurotransmitters and Synaptic Transmission Neurons work together through –Synapse –Synaptic gap –Neurotransmitters: excitatory, inhibitory –Synaptic vesicles –Synaptic terminals –Receptor sites Brain can be altered by use of drugs Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 9 Neurotransmitters and Synaptic Transmission Glial cells –Outnumber neurons –Produce myelin sheath –Uses chemical ATP (adenosine triphosphate) Biological foundations of Behavior Chemicals in brain –Acetylcholine –Dopamine –Serotonin –Norepinephrine –Glutamate –Neuropeptides

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 10 Divisions of the Nervous System Central Nervous System –Brain and spinal cord –Interneuron Peripheral Nervous System –Branches to all parts of body from CNS –Afferent and efferent neurons Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 11 Direction of impulse Muscle contracts and withdraws part being stimulated Axion of efferent neuron Pain receptors in skin Axion of afferent neuron Cell body of interneuron Cell body of afferent neuron Dendrite of afferent neuron Cell body of efferent neuron Hot object

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 12 Divisions of Peripheral Nervous System Somatic nervous system –Voluntary movements and skeletal muscles –Receives and send messages Autonomic nervous system –Carries messages to organs, has 2 functions Essential body functions Emotion Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 13 Divisions of Autonomic Nervous System Sympathetic nervous system –Responds to psychological or physical stress –Activates and inhibits organs Parasympathetic nervous system –Helps maintain balanced regulation of internal organs and large body muscles –Stimulates maintenance activities and energy conservation Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 14 Structures and Functions of the Brain Hindbrain –Routine functions that keep body working –Three main parts Medulla – breathing and reflexes Pons – balance, hearing Cerebellum – coordinates complex muscle movements Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 15 Hindbrain and Midbrain Medulla Pons Cerebellum Midbrain

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 16 Structures and Functions of the Brain Reticular formation –Spans medulla and pons –Influence wakefulness, arousal, attention, –Muscle control and cardiac responsiveness Midbrain –Center for postural reflexes linked to senses Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 17 Forebrain: Cognition, Motivation, Emotion, and Action Forebrain – two distinct areas –Thalamus, hypothalamus, most limbric system Thalamus – message switching station Hypothalamus – motives and emotions Amygdala system – aggression, emotions Hippocampus – memories Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 18 Forebrain Thalamus Hypothalamus Cerebral Cortex

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 19 Limbic System Cingulate Cortex Septal Area Amydala Hippocampus

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 20 Forebrain: Cognition, Motivation, Emotion, and Action Forebrain – two distinct areas –Primarily cerebral cortex Sensory, cognitive, and motor functions Conscious experiences Voluntary actions Language and intelligence Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 21 Lobes of the Cerebral Cortex Lobes – four sections of brain –Frontal lobes – thinking, memory, decisions Broca’s area – ability to speak Phineas Gage –Association areas – general roles in cerebral activities Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 22 Wernicke’s area Broca’s area Motor area Somatosensory Voluntary movement and thinking Body sensations Vision Hearing The Brain’s Four Lobes

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 23 Images of the Brain at Work Techniques create images –Electroencephalogram (EEG) –Positron emission tomography (PET) –Magnetic resonance imaging (MRI) Functional MRI measures Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 24 Functions of the Hemispheres of the Cerebral Cortex Biological foundations of Behavior Corpus Callosum

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 25 Functions of the Left and Right Cerebral Hemispheres Left cerebral hemisphere –Language control in 90% of population –Analyzes logical verbal information Right cerebral hemisphere –Processes shapes and location of things –Visual and spatial information Corpus callosum Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 26 Split Brains Severed corpus callosum Psychological experiments reveal processing limitations of hemispheres –Optic chiasm not severed Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 27 Hemispheres of the Cerebral Cortex and Emotion Left hemisphere –Processes positive emotions –Stroke in left hemisphere – depression Right hemisphere –Processes negative emotions –Stroke in right hemisphere – no depression Plasticity of cortex Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 28 Human Diversity: Sex Differences in the Cerebral Cortex Female brain – average size smaller than that of male brain –More folds and complex –Greater surface area –More accurate in verbal task performance –More activation in left cerebral hemisphere Male brain –More activation in right cerebral hemisphere Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 29 The Brain is a Developing System Brain structure changes over lifetime Total brain weight same after age 5 –Gray matter decreases as white matter increases in cerebral cortex –White matter: continued myelin growth but decreases after fifth decade of life –Gray matter decrease: neural pruning –Neurogenesis: controversial issue Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 30 The Brain is an Interacting System Cerebral cortex – evaluates threats Limbic system – process emotional arousal Motor areas of cortex work with hindbrain and midbrain to coordinate muscular movements Parallel rather than serial processing Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 31 Endocrine System: Chemical Messengers of the Body Endocrine system – regulation of bodily processes –Glands – secrete neuropeptides and hormones –Hormones Directly regulated by brain Chemically identical to some neurotransmitters Activate body organs during physical stress or emotional arousal Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 32 Glands Pituitary Gland –Largely controlled by hypothalamus –Regulates body’s reaction to stress and resistance to disease Adrenal glands –Pair of glands atop kidney –Secrete variety of hormones in emotional arousal Epinephrine and norepinephrine Cortisol Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 33 Islets of Langerhans Embedded in pancreas – regulate sugar in blood Glucagon – causes liver to put sugar in blood stream Insulin – reduces sugar level in blood Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 34 Glands Gonads – produce sex cells –Ovaries and estrogen –Testes and testosterone Thyroid gland –Regulation of metabolism –Secretes thyroxin –Serious deficiency: cretinism, rare type of mental retardation Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 35 Glands Parathyroid glands –Four small glands in thyroid –Secrete parathormone –Regulates ion levels in neurons Too much – lethargy Too little – excessive nervous activity Pineal gland –Attached to top of thalamus –Secretes melatonin – regulates moods Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 36 Genetic Influences on Behavior What is inherited? –Physical traits –Specific behavioral patterns Biological mechanisms of inheritance –Genetic codes Mendel – science of genetics Genes, chromosomes, and DNA Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 37 Genetic Influences on Behavior Biological mechanisms of inheritance –Sex cells Gametes Fertilization and zygote –Dominant and recessive genes and traits –Chromosome abnormalities Down syndrome –Genes influence on mental processes Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 38 Research on Inheritance in Humans Studies of twins –Monzygotic: identical twins –Dizygotic: fraternal twins Studies of adopted children –Heredity and environmental influences Biological foundations of Behavior

© 2007 The McGraw-Hill Companies, Inc. All Rights Reserved Slide 39 The End 3 Biological Foundations of Behavior