1 Chapter 3: The Biological Bases of Behavior

2 Communication in the Nervous System Hardware: 1) Glia: structural support and insulation (Glue) 2) Neurons: communication (receives, integrate & transmits) Dendrites – receive message Soma – cell body Axon – transmit message Myelin sheath- speeds up transmission Terminal Button- end of axon, release message Synapse- gap between Button & Dendrite

3 Structure of the Neuron

4 The Neural Impulse 1) Resting Potential- Neuron is Ready ›-70 millivolts 2) Action Potential- Neuron Fires (down axon) ›Sodium + ions flow in, Potassium - ions flow out 3) Refractory Period- Neuron is Recharging ›The minimum time after firing, cannot fire until charged All or None Principle- Neuron fires at the same speed whether it was strong or weak. Either fires or doesn't.

5 The Neural Impulse

6 The Synapse: Chemicals as Signal Couriers Neurotransmitters: is the chemical message that transmit info from one neuron to another. –Presynaptic neuron (Terminal Button) Synaptic vesicles: Contain Neurotransmitters –Postsynaptic neuron (Dendrites) Receptor sites: Located on dendrites, each receptor site receive specific neurotransmitters

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8 When a Neurotransmitter Binds: The Postsynaptic Potential Postsynaptic Potential (PSP) Changes the probability of the postsynaptic neuron firing –Excitatory PSP: Positive voltage shift, increase firing –Inhibitory PSP: Negative voltage shift, decrease firing Reuptake: All the excess neurotransmitters that don’t bind to a receptor site get sucked up into the terminal button Synaptic connections –Elimination and creation –Synaptic pruning

9 Overview of Synaptic Transmission

10 Synaptic Pruning

Types of Neurons Sensory Neurons –Nerves that carry information to the central nervous system Connect the sense organs to the brain and spinal cord Motor Neurons –Nerves that carry information from the central nervous system Carries messages from the brain and spinal cord to other parts of your body Inter Neurons –Nerve cells in the brain and spinal cord responsible for processing information related to sensory input and motor output 11

The Neural Chain 12

13 Neurotransmitters Specific neurotransmitters work at specific synapses –Lock and key mechanism –(15 – 20) neurotransmitters known at present Agonist – mimics neurotransmitter action Antagonist – opposes action of a neurotransmitter

14 Common Neurotransmitters and Some of their Functions

15 Neurotransmitter Helpful Hints ACh- AAMM DA- Sell Dope at the Park (Parkinson) Movement & Pleasure NE- Norma PMS (Mood & Arousal) Serotonin- Sleep/Wakefulness, Eating/Aggression (Ninja Turtles, SEWA) GABA- Inhibitor Endorphins- Natural pain reliever

16 Organization of the Nervous System Central nervous system (CNS)  Brain & Spine (It is the center) –Hindbrain. Back bottom –Midbrain. Core –Forebrain. Outer Peripheral nervous system (PNS)  Bones. Organs. Muscles. (Is everything else) –Somatic nervous system (SNS) voluntary Afferent = (In) toward the CNS Efferent = (Out) away from the CNS –Autonomic nervous system (ANS) automatic Sympathetic (Fight or Flight) Parasympathetic (Calming)

17 Organization of the NS

18 The CNS & PNS

19 The Autonomic Nervous System (ANS)

20 Studying the Brain: Research Methods Electroencephalography (EEG). Brain Waves Damage studies/lesioning Electrical stimulation (ESB). Mapping out the Brain Brain Imaging – –CT Scan (computerized tomography). X-Ray of brain structure –PET Scan (positron emission tomography). Brain function, shows activity in the brain with radioactive glucose. –MRI Scan (magnetic resonance imaging). 3D pictures –fMRI Scan (functional magnetic resonance imaging). Additional oxygen & blood flow. Structure & function

21 Accidents Phineas Gage Story Personality changed after the accident. What this this tell us? That different part of the brain control different aspects of who we are.

22 Lesions Purposeful removal or destruction of some part of the brain. Frontal Lobotomy

23 Brain Regions & Functions Hindbrain: –Medulla. vital functions –Pons. facial expression, sleep & dreaming –Cerebellum. movement & balance Midbrain: (Plug into hard drive) –Reticular Formation. sensory functions Forebrain: –Basal ganglia. Regulates muscle contraction/movements –Thalamus. All senses except smell –Hypothalamus. 4 “F’s” –Limbic system Hippocampus. Learning & Memory (Hip to the campus) Amygdala. Emotion (Amy is emotional) –Cerebrum. Outer layer of brain (largest) is covered by… –Cerebral cortex. Wrinkles in the outer layer 1.5 sqf (gray matter)

24 The Cerebrum: Two Hemispheres, Four Lobes Cerebral Hemispheres – two specialized halves connected by the corpus callosum Contralateral Control- each hemisphere controls opposite sides of the body –Corpus Collosum- connects the hemispheres Lateralization- left & right hemispheres have different functions –Left hemisphere – verbal processing: language, speech, reading, writing –Right hemisphere – nonverbal processing: spatial, musical, visual recognition

25 The Cerebrum: Two Hemispheres, Four Lobes Four Lobes: –Occipital – vision –Parietal – somatosensory/motor cortex –Temporal - auditory –Frontal – movement, executive control systems

26 Structures & areas in the human brain

27 Brain Reorganization Corpus Callosum neural fiber connecting the 2 brain hemispheres & carrying messages between the hemispheres. Split Brain was used to cure epilepsy by cutting the corpus callosum. Brain Plasticity is the brain’s capacity to overcompensate for a loss of a brain function. Higher in children.

28 The Cerebral Hemispheres & The Corpus Callosum

29 Spilt Brain

30 The Cerebral Cortex in Humans

31 The Primary Motor Cortex

32 Language processing in the brain

33 The Endocrine System: Hormones Hormones – Chemical messengers produced by the endocrine glands and circulated in the blood Similar to neurotransmitters in that they are also messengers Slower communication system, but with longer lasting effects

The Endocrine System: Glands Endocrine glands –Pituitary – “master gland,” growth hormone –Thyroid – helps regulate the energy level in the body metabolic rate –Adrenal – help to arouse the body in times of stress, Located above the kidneys, Release epinephrine (adrenaline) and norepinephrine –Pancreas – regulates the level of sugar in the blood –Gonads – sex hormones, Ovaries (females) and testes (males) influence emotion and physical development. 34

35 Genes & Behavior: The Field of Behavioral Genetics Behavioral genetics = the study of the influence of genetic factors on behavioral traits Chromosomes – strands of DNA carrying genetic information –Human cells contain 46 chromosomes in pairs (sex-cells – 23 single) –Each chromosome – thousands of genes, in pairs Dominant, recessive/Homozygous, heterozygous Genotype- Genetic makeup Phenotype- manifested in characteristics Polygenic Inheritance- characteristics influenced by more than one gene

36 Genetic Material

37 Research Methods in Behavioral Genetics Family studies – does it run in the family? Twin studies – compare resemblance of identical and fraternal twins on a trait Adoption studies – examine resemblance between adopted children and their biological and adoptive parents

38 Genetic Relatedness

39 Family studies of risk for Schizophrenic Disorders

40 Twin studies of Intelligence &Personality

41 Modern Approaches to the Nature vs. Nurture Debate Molecular Genetics = the study of the biochemical bases of genetic inheritance –Genetic mapping – locating specific genes - The Human Genome Project Behavioral Genetics –The interactionist model –Richard Rose (1995) – “We inherit dispositions, not destinies.”

42 Evolutionary Psychology: Behavior in Terms of Adaptive Significance Based on Darwin’s ideas of natural selection –Reproductive success key Adaptations – behavioral as well as physical –Fight-or-flight response –Taste preferences –Parental investment and mating