Examining Brain Structures • Electroencephalogram (EEG): An amplified readout of the electrical activity of the brain’s billions of neurons sweeps in regular waves across its surface • Magnetoencephalography (MEG): Related technique using the brain’s magnetic fields • Positron Emission Tomography (PET): Depicts brain activity by showing brain area’s consumption of chemical fuel • Magnetic Resonance imaging (MRI): Detects brain’s spinning atoms in a strong magnetic field and gives an image of the structure • Functional MRI (fMRI): Detects the brain’s functioning Brain Structures Older Brain Structures Brainstem • Brain stem and medulla • Controls heartbeat and breathing • Brain-damage patients in a vegetative state demonstrate that we need no other high-order structures to maintain heart pumping and lung’s breathing Thalamus • Brain’s sensory control center • Seeing, hearing, tasting, and touching Reticular Formation • Netlike formation • Controls arousal • Filters incoming stimuli and relays important information to other brain areas • Assists with multitasking How long have you been sitting here? Do your clothes feel soft or rough against your skin? How’s your mood today? Cerebellum • Deep brain structures involved in motor movement • Enables nonverbal learning and skill memory • Judge time, discriminate textures and sounds, control emotions and social behaviors, vocabulary, reading, and storing information • Coordinates voluntary movement • Under alcohol influence, coordination and balance suffers The Limbic System Limbic System • Associated with emotions and drives The Amygdala • Enables aggression, fear, and rage • Researchers once removed a rhesus monkey’s amygdala which turned an ill-tempered animal into a mellow creature Case of Charles Whitman The Hypothalamus • Influence hunger, regulate thirst, body temperature, and sexual behavior • Helps maintain a steady or homeostatic state • Considered the reward center • Those genetically prone to a reward deficiency syndrome may crave what provides this missing pleasure (e.g., aggression, fattening foods, drugs) The Hippocampus • Processes conscious, explicit memories • Variations in development predict academic achievement • Injury can cause loss of ability to form new memories of facts and events • NFL players with frequent concussions may have a shrunken hippocampus and poor memory The Cerebral Cortex Cerebral Cortex • Covers the hemispheres • Contains 20 to 23 billions of the brain’s nerve cells • 300 trillion synaptic connections Lobes of the Cortex • Frontal lobes: muscle movements and judgement, decision making • Parietal: touch and sensory input • Occipital: visual fields • Temporal: auditory • Motor: voluntary movements Functions of the Cortex • Motor cortex: Stimulating parting of this region in the left or right hemisphere caused movements of specific body parts on the oppositive side of the body • Predict movements by repeatedly motor cortex activity preceding specific arm movements Functions of the Cortex • Sensory functions • Somatosensory cortex: Area that specializes in receiving information from the skin senses such as touch and temperature • Stimulate a point on the top of of this band of tissue and a person may report being touched on the shoulder Functions of the Cortex • Association areas: Areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions • Learning, remembering, thinking, and speaking • Found in all four lobes • Prefrontal cortex: judgement, planning, social interactions, and processing of new memories • Damage in these areas can mean that someone may have a high IQ but unable to manage time • Frontal lobe damage can alter personability and remove inhibition Responses to Damage • The brain engages in self-repair by reorganizing existing tissue • Neurogenesis: producing new neurons • Specific to different individuals The Divided Brain • Right-Left differences in the intact brain • Right and left hemispheres perform distinct functions • Right hemisphere: perceptual tasks, making inferences, modulating speech, orchestrate self-awareness • Left hemisphere: match calculations, making quick and literal interpretations of language Splitting the Brain • Epileptic patients and the functions of right and left brain