Biological Basis of Behavior PDF

CHAPTER 3: BIOLOGICAL BASIS OF BEHAVIOR Nervous system divided to 2 PARTS CENTRAL NERVOUS SYSTEM (CNS): Contains brain, spinal cord, optic nerve, retina PERIPHERAL NERVOUS SYSTEM(PNS): sympathetic/parasympathetic, EVERYTHING ELSE BRAIN Contains 2 NERVE CELLS: - NEURONS: Unit of nervous system,...

CHAPTER 3: BIOLOGICAL BASIS OF BEHAVIOR Nervous system divided to 2 PARTS CENTRAL NERVOUS SYSTEM (CNS): Contains brain, spinal cord, optic nerve, retina PERIPHERAL NERVOUS SYSTEM(PNS): sympathetic/parasympathetic, EVERYTHING ELSE BRAIN Contains 2 NERVE CELLS: - NEURONS: Unit of nervous system, requires glucose for function - GLIAL CELLS: Provides structural/nutritional help to brain NEURON composed of DENDRITES, CELL BODY, AXON, AXON TERMINAL CELL BODY(SOMA): Integrates electrical signals DENDRITE: Extension of cell body, collects information from other neurons AXON: Conducts information to other neurons, could be myelinated or unmyelinated AXON TERMINALS: Contact dendrites of other neurons AXON TERMINAL AND COMMUNICATION BETWEEN NEURONS - Inside axon terminal are synaptic vesicles(neurotransmitters) - When action potential travels down axon, synaptic vesicles bind to wall of terminal and release neurotransmitters into synaptic cleft between the 2 neurons - They then bind to receptors on the dendrites of other neuron NEURAL IMPULSE (ACTION POTENTIAL) Within neurons are POTASSIUM IONS Outside of neurons are SODIUM IONS - Potassium inside are positively charged but proteins within make the overall charge INSIDE the neuron NEGATIVE - OUTSIDE of neuron is POSITIVELY CHARGED This negative/positive charged create a POTENTIAL for an electrical charge to occur, so neuron membrane separates them until needed PRESYNAPTIC NEURON: neuron releasing neurotransmitters into synaptic cleft POSTSYNAPTIC NEURON: neuron that receives the neurotransmitters NEUROTRANSMITTERS:  1) ACETYLCHOLINE(ACh) - Released by motor neurons for skeletal movement (found in poisons also) - Contributes to regulation of attention, arousal, memory, sleep - Nicotine stimulates, alzheimers associated with low levels of ACh 2) MOANIMINES (DOPAMINE)(DA) - Contributes to control of voluntary movement - Cocaine/Amphetamines elevate dopamine activity - Schizophrenia implicated as OVERACTIVITY of dopamine - Reward pathway (SEROTONIN)(5-HT) - Involved in regulation of sleep/wakefulness, eating, aggression - Prozac and other antidepressants affect serotonin circuits (increase serotonin) (NOREPINEPHRINE)(NE) - Brain arousal and functions like mood, hunger, sleep, sexual behavior - Functions as hormone and neurotransmitter - Adrenaline basically 3) AMINO ACIDS (GABA) - Brain's main INHIBITORY transmitter - Contributes regulation of anxiety, sleep, arousal - Anti anxiety drugs work at Gaba synapses (GLUTAMATE) - Main EXCITATORY neurotransmitter in nervous system - Relay of sensory information and learning (too much = schizophrenia) 4) ANANDAMIDE (unconventional neurotransmitter) - Binds to same receptors as THC(Cannabis) - Plays role in eating, memory, motivation, sleep (Cannabis symptoms) 5) NEUROPEPTIDES (ENDORPHINS) - Regulated by PNS, synthesized in pituitary. - Function as HORMONE and neurotransmitter - Naturally occurring painkiller - Inhibit communication of pain signals to spinal cord NERVOUS SYSTEM (neurotransmitters) is FAST COMMUNICATION SYSTEM, ENDOCRINE SYSTEM (hormones) is SLOWER COMMUNICATION (released into blood) NEURAL PLASTICITY: Nervous system has the ability to adapt/change NEURAL PLASTICITY IN EARLY DEVELOPMENT: 1) Growth of dendrites/axons 2) Synaptogenesis (formation of new synapse)(neurons exchanged through synapse) 3) Pruning (removal of extra synapses to increase efficiency)(occurs until 10, 70% of neurons destroyed 4) Myelination (growth of myelin sheaths) NEURAL PLASTICITY AND LEARNING: - Could occur through STRUCTURAL CHANGES Axonal growth Dendrite branching/growth Enriched environments lead to axonal growth/dendrite branching more POTENTIATION: When a specific presynaptic neuron has a greater say in the postsynaptic neurons ability to fire (EX: unfair democracy, where ONE person has more power)(“neurons that fire together wire together”) NEURAL PLASTICITY FOLLOWING INJURY - Brain can take over functions previously performed by other parts - Searching for treatments to promote healing/prevent damage in brain (stem cells) - Neurogenesis (creation of new neurons in adult brain)(very few) THE MENINGES: 3 LAYERED PROTECTIVE MEMBRANE that covers brain & spinal cord - Dura Mater - Arachnoid Mater - Pia Mater FURTHER PROTECTION: CEREBRAL VENTRICLES containing cerebrospinal fluid FRONTAL LOBE: Has the Central Sulcus, divides frontal & parietal lobe - Primary Motor Cortex: part of frontal lobe responsible for body movement - Prefrontal Cortex: responsible for thinking, planning, language PARIETAL LOBE: Processes touch information, integrates vision and touch TEMPORAL LOBE: Processes auditory information, language, autobiography memory - Wernicke's Area: part of temporal lobe involved in understanding speech OCCIPITAL LOBE: Back part of cerebral cortex, specialized for vision SUBCORTICAL STRUCTURES (beneath the cerebral cortex) THE BASAL GANGLIA - Group of nuclei (clusters of neurons) located beneath the cerebral cortex - Involved in goal motivated motor control - Contains dopamine neurons and associated with reward and motivation LIMBIC SYSTEM: includes THALAMUS, HYPOTHALAMUS, HIPPOCAMPUS, AMYGDALA - THALAMUS: Gateway from sense organs to primary sensory cortex All sensory information, except smell, relayed through thalamus - HYPOTHALAMUS: Bridge between CNS and Endocrine system Regulates the pituitary gland Responsible for: FLEEING, FIGHTING, FEEDING, FORNICATION - HIPPOCAMPUS: Regulates spatial memory, humans have 2 hippocampi May be necessary for formation of new memories - AMYGDALA: Plays key role in fear, excitement, and arousal