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Chapter 3. Biological Processes. Biopsychology/Neuroscience. Brain and the computer Biopsychology – interaction between behavior, brain, and environment Neuroscience – several sciences interested in brain function Anatomy – parts Physiology – how they work. Your brain… right now.
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Chapter 3 Biological Processes
Biopsychology/Neuroscience • Brain and the computer • Biopsychology – interaction between behavior, brain, and environment • Neuroscience – several sciences interested in brain function • Anatomy – parts • Physiology – how they work
Your brain… right now • What is your brain doing right now? • What processes are occurring? • Think about basic (e.g. breathing) to complex processes.
Phrenology • Franz Joseph Gall: • Shape of the brain is determined by development of each “organ” of the brain where size = power • Skull takes shape from brain • By examining skull, can realize person’s character traits and intellectual aptitudes
Phrenology • Wanted to correlate behavior with particular regions of the brain – localization of function • Gall sought onlyconfirmationsof his hypotheses • did not apply the same standard to contradictory evidence
Forebrain Hindbrain Brain Structures Limbic Tectum, substatianigra, inferior & superior colliculus
Brain Structures • All the structures have functions • Hindbrain: most primitive part – survival – medulla, pons, reticular formation, cerebellum • Midbrain: relay stations – input from several places – tectum, superior colliculus, inferior colliculus, substnigra • Forebrain: higher mental function – cerebral cortex (80% of volume), thalamus, hypothalamus, limbic system (amygdala), hippocampus • Corpus callosum – bridges 2 hemispheres
Cerebral Cortex • Cerebral Cortex: outermost layer (80% of brain) • Convolutions/wrinkles and grooves/fissures • Longitudinal fissure – separates left and right hemisphere (nerve fibers = corpus callosum) • Central fissure – separates front and back • Lateral fissure – separates top and bottom (side) • 4 lobes – most regions play multiple roles • Frontal lobe: planning/problem solving --- Phineas Gage (frontal lobotomy – calm disorders) • Parietal lobe: sensation • Temporal lobe: hearing, speech (Wernicke’s area – comprehension) • Occipital lobe: vision
Sensory & Motor Cortex • Primary motor area • Localization maps (homunculus) • Contralateral control • Primary sensory area • Localization maps and contralateral too • Vision and hearing in occipital and temporal lobes
Neurons • Receive, transmit, interpret • Types of neurons • Sensory neuron also called afferent • Motor neuron also called efferent • Interneuron – from sensory to motor
Neurons Total neurons thousand billion – each neuron connecting to ten thousand
Electrical neuronal communication • Cell is not firing: resting potential (negative) • Cell fires: action potential (positive voltage) • All-or-none signal • Must exceed threshold in axon hillock • Refractory period
Electrical neuronal communication • How do we get different strengths of feelings if all or none AP? • Stimulus intensity is in how quickly the cell fires • How many APs occur in a time period • How many neurons fire
Chemical neuronal communication:Neurotransmitters Lock and key
Neurotransmitters • Acetylcholine (ACh) • Movement, Alzheimer’s • Dopamine (DA) • Movement, attention, Parkinson’s • Norepinephrine (NE) • Mood • Serotonin (5-HT) • Mood and arousal • GABA • Anxiety, panic
Methods of Investigation • Lesions – 1850 (no pain) • Activating the brain • Direct stimulation
Methods of Investigation • Imaging technology - Structure • CT – x-rays • MRI – rebound of nuclei from • Imaging technology - Structure • EEG: electroencephalography – electrodes on scalp • PET – active cells take more injected sugar - blood flow • fMRI – blood flow & oxygen use
Disorders • Apraxia • Disturbance in initiation of voluntary action • Speech apraxia: can’t move jaw • Agnosia: • Can’t identify objects using affected sensory modality • Visual agnosia • Prosopagnosia: Can not recognize objects – especially faces • Neglect syndrome: • One side of visual field is not perceived • Aphasia: • Problem with production or comprehension • Broca’s area, left frontal lobe – speech production http://www.youtube.com/watch?v=f2IiMEbMnPM • Wernicke’s area, left temporal/parietal lobe - comprehension
Aphasia • Paul Broca • Observed brain lesion in left hemisphere of patient with aphasia • Carl Wernicke • Observed man whose language made no sense
Neuropharmacology Neuropharmacology • Other chemicals affect release, uptake, or reuptake • Receptor antagonists inhibit uptake - bind to receptor sites & block neurotransmitter • Receptor agonists boost or mimic neurotransmitters
Agonist substitution: give another drug w/similar makeup • EX methadone for heroin; nicotine patches/gum • - but can develop tolerance, lose analgesia/sedation • - can also become addicted to new drug
Antagonist drugs: block/counteract effect of drug EX naltrexone for opiates • can reduce craving for drug • but must be motivated to take • can also cause withdrawal sxs if begun before other drug is discontinued
Genetic Research Consanguinity/Family Study • Compare people who share more/fewer genes
Genetic Research Twin Study • Compare MZ twins & DZ twins • MZ reared together vs. apart
Genetic Research Adoption Study • Compare adopted children to their biological & adoptive parents