BRAIN AND BEHAVIOR

WHY DO PSYCHOLOGISTS STUDY THE NERVOUS SYSTEM? The nervous system is the direct source of all behavior The nervous system is shaped by our experiences and behaviors The brain is infinitely interesting and remains to be completely understood!

NEURONAL STRUCTURE Cell body Dendrites Axon –Terminal buttons Vesicles Transporter molecules –Myelin

SYNAPSE Synapse - gap between two neurons

COMMUNICATION WITHIN A NEURON Action potential –Brief electrical charge that travels down an axon Charged ions move in and out of the membrane

COMMUNICATION WITHIN A NEURON Action potentials –Threshold of excitation –Cell body to terminal buttons –All-or-none firing –Rate of firing

COMMUNICATION BETWEEN NEURONS Neurotransmitters –Chemical messengers Released when action potential reaches the terminal button Carry message across the synapse Fit into receptors on the receiving neuron –Excitatory –Inhibitory

COMMUNICATION BETWEEN NEURONS Synaptic communication is terminated when neurotransmitter is removed from the synapse –Reuptake –Enzymatic deactivation

NEUROTRANSMITTERS Acetylcholine Dopamine Norepinephrine Serotonin Glutamate GABA + many others!

DRUGS All psychotropic drugs work by binding to receptors in the brain –Agonists –Antagonists Drug effects have lead to discoveries about brain chemistry

NERVOUS SYSTEM Central nervous system - Brain - Spinal cord Peripheral nervous system - All nerves extending from CNS

NERVOUS SYSTEM

Autonomic nervous system controls physiological arousal ____________ division (arousing) ___________ division (calming) Pupils dilate EYES Pupils contract Decreases SALIVATION Increases Perspires SKIN Dries Increases RESPIRATION Decreases Accelerates HEART Slows Inhibits DIGESTION Activates Secrete stress hormones ADRENAL GLANDS Decrease secretion of stress hormones

TYPES OF NEURONS Sensory neurons Motor neurons Interneurons

REFLEXES Automatic responses to stimuli –Occur entirely within the spinal cord

BRAIN DIVISIONS & REGIONS Brain stem –Myelencephalon Medulla –Metencephalon Cerebellum –Mesencephalon Reticular formation

Diencephalon –Thalamus –Hypothalamus BRAIN DIVISIONS & REGIONS

Telencephalon –Cerebral cortex –Limbic system –Basal ganglia BRAIN DIVISIONS & REGIONS

CEREBRAL CORTEX Frontal lobe Temporal lobe Parietal lobe Occipital lobe

CEREBRAL CORTEX Frontal lobe –Prefrontal cortex –Motor cortex Parietal lobe –Somatosensory cortex Temporal lobe –Auditory cortex Occipital lobe –Visual cortex

LATERALIZATION OF CORTICAL FUNCTION Left hemisphere –Language areas Broca’s area Wernicke’s area –Analyzing sequences Right hemisphere –Emotion –Spatial relations

CORPUS CALLOSUM Connects the two cortical hemispheres

SPLIT BRAIN PATIENTS In all mammals –Information from the left visual field is analyzed in the ___________ occipital lobe –Information from the right visual field is analyzed in the ___________ occipital lobe If the corpus callosum is severed –Objects presented in the right visual field _________ be named –Objects presented in the left visual field _________ be named.

LIMBIC SYSTEM Hippocampus Amygdala Nucleus accumbens

BASAL GANGLIA Coordinates balance and motor output –Caudate –Putamen –Globus pallidus