Unit 2 : Biopsychology

Alternative transcript:

impulses from brain or spinal cord to muscles or glands ● O Interneurons: transfers impulses between afferent & efferent neurons • Synapse - microscopic space between neurons O When an impulse reaches the terminal button of the neuron sending the impulse ■ This neuron is the presynaptic neuron ■ The chemicals that are released into the synapse is the neurotransmitters O Neurotransmitters move across the synapse & bind on dendrites of the postsynaptic neuron (receiving the impulse) Neurotransmitters O Excitatory: will start a new impulse in the postsynaptic neuron o o Inhibitory: will suppress an impulse from starting on the postsynaptic neuron Reuptake process: occurs when NT's that didn't bind with receptors on postsynaptic neurons are absorbed back into the presynaptic neuron Acetylcholine (Ach) O ■ Excitatory or inhibitory ■ Classified as neuromodulator (a NT that regulates the actions of large groups of neurons) ■ released in motor neurons (muscle contractions) ■ Located in neurons located in hippocampus o Dopamine O ● Part of brain that forms new memories ■ Excitatory or inhibitory ■Found in motor neurons that control muscle movement ■ Released in the dopamine reward pathway (active when we experience sensations of pleasure) o Endorphins ■ Inhibitory (involved with pain relief) ■ Endogenous morphine: morphine that is produced in body When released it can produce a mild euphoric effect Serotonin ■ Excitatory or inhibitory ■ Regulates metabolic functions that can fluctuate throughout the day (appetite, sleep, body temperature) ■ LINKS TO MOOD CHANGE Gama Aminobutyric Acid (GABA) ■ Inhibitory Inhibits the function of interneurons within the brain Glutamate ■ Excitatory Active during memory formation ■ Role in the development of the nervous system (neuroplasticity) ● Abnormalities in specific neurotransmitters have been linked to certain mental and neurological illnesses. o Schizophrenia = high level in dopamine o Anxiety disorder =low level of GABA O Alzheimer's disease = low level in Ach (memory loss); over activated Glutamate causes neural cell death O Parkinson's disease = low level of dopamine (poor motor control) o Depression: low level of serotonin ■ Antidepressants are Selective serotonin reuptake inhibitors. (SSRI) Slow down the reuptake process and maintain high levels of serotonin O Runner's high: release of endorphins during strenuous activities. O Drugs can enhance NT's effects due to its purpose. ■ Cocaine-> dopamine ■ Alcohol-> GABA Action Potential: electro-chemical process which generates an impulse within the neuron o Resting potential: neuron is NOT producing an impulse but has capacity to O Action potential begins when: ■ Activated by a receptor cell Receives an impulse from another neuron o Refractory period: neuron is repolarizing & Na/K (sodium and potassium) pump is active ➡ During the action potential the movement of Na & K ions across the membrane of the neuron creates an electrical current; this current is the impulse Although action potentials occur rapidly, a neuron must repolarize (go back to its resting potential) before another action potential can be produced To repolarize; A the neuron's sodium/potassium pump moves the Na and K ions back to their original positions so the process can begin again ● The Reflex Arc: adaptive neurological response often triggered by the unexpected detection of a painful stimulus The Reflex Arc 1. Receptor cells in the skin detect a painful stimulus and triggers an impulse in a sensory (afferent) neuron 2. Impulse is carried by sensory neurons to interneurons of the spinal cord 3. From the spinal cord interneurons, the impulse is transferred to the mofor (efferent) neurons 4. The motor neuron causes the muscles of the arm (an effector) to contract, so the arm can quickly move away from the painful stimulus O ● Structure of the Brain (4 major parts) O Hindbrain or brainstem O Midbrain O Forebrain o Cerebral cortex ● Hindbrain or Brainstem O White matter Gray matter Central Canal O Dorsal root DORSAL Cell body of sensory neuron Inter neuron Sensory neuron Motor Ventral neuron VENTRAL Cell body of Root motor neuron Pain is processed by the spinal cord b4 the brain to ensure fastest possible reaction to painful stimuli lessening potentially damage O Conscious awareness of the source of pain allows it to be recognized & remembered so it can be avoided in the future O Most primitive part of the brain O Medulla: controls vital biological functions such as breathing, regulation of heartbeat, and swallowing Cerebellum "little brain": controls involuntary muscle movements necessary for BALANCE Receptor (in skin) Effector (muscle) Pin prick ■ Coordinates voluntary muscle movements that are performed in rapid succession or require precise control ■ Ex) walking, playing a musical instrument, writing, etc. O Pons "bridge": transmits impulses between the cerebellum and the more complex motor regions of the brain ■ Influences DEEP SLEEP AND DREAMING STATES Reticular Formation: network of neurons embedded within the brainstem ■ Activates sensory regions of the brain needed to maintain alertness and attention. ● Midbrain o Coordinates muscle movements to allow eyes and ears to better focus on particular sights and sounds o Ex) saccadic eye movements (quick movement of eyes that occurs while reading) Forebrain or Limbic system o Located above brainstem but below cerebral cortex o Hippocampus: active during the FORMATION of memories; which are then stored in other parts of the brain o Amygdala: FEAR responses and active during emotional learning o Hypothalamus: regulates metabolic functions (body temperature, thirst, feelings of hunger, transitioning between sleep) ■ Detects biological needs and triggers functions to meet those needs ■ Link between nervous and endocrine system ■ Stimulates the pituitary gland which triggers the function of all other glands in the body ■ A Reward center -> it triggers the sensations associated with sexual activity Thalamus: directs information from sensory organs onto more complex brain regions where they are interpreted o Olfactory bulb: interprets impulses from the sensory neurons and receptor cells in the nasal cavity. Cerebral cortex O O Most developed O Divided into 4 lobes each of which are further divided into cortices Frontal lobe O Motor cortex = voluntary muscle movements ■ Right side of the brain controls left side of the body; left side of the brain controls right side of the body Prefrontal cortex = executive cognitive functions such as ability to plan, reason and make decisions. ■ The Phineas Gage Case Study (1850) O O Broca's Area = language production ■ Only on left side of frontal lobe ■ Damage to this area causes Broca's aphasia (difficulty speaking fluently) ● Parietal Lobe o Somatosensory cortex = interprets bodies' tactile sensations Tactile sensations are detected by the right side of the body and processed by the left portion of the brain. (Vice versa) Temporal lobe O Wernicke's area (only on left side of lobe) coordinates language comprehension ● ● O ■ Damage to the area is called Wernicke's aphasia. Speech is fluent but meaning and comprehension is impaired Auditory cortex interprets auditory sensations ■ Impulses from left ear are processed by right side of temporal lobe (Vice versa) Occipital lobe O Visual cortex= visual sensations o Right visual field is processed by left visual cortex (Vice versa) Brain Lateralization O O Cerebral cortex is divided into 2 hemispheres (left and right hemisphere) that controls its own unique set of cognitive functions Corpus callosum= 200 million nerve fibers that connect the left and right hemispheres ■ allows for impulse transfer between the hemisphere ■ Roger Sperry: had a surgical procedure done on research patients where the corpus callosum is served to prevent the spread of epileptic seizures Micheal Gazzinga: conducted research into how the left and right hemispheres communicate with each other ■ ● Corpus callosum was removed in both researcher's experiments because they wanted to see how the hemispheres individually function LEFT-BRAIN FUNCTIONS Analytic thought Logic Language Reasoning Science and math Written Numbers skills Right-hand control RIGHT-BRAIN FUNCTIONS Art awareness Creativity Imagination Intuition Insight Holistic thought Music awareness 3-D forms Left-hand control Split Brain Research OF TWO MINDS Experiments with split-brain patients have helped to illuminate lateralized nature of brain function. Split-brain patients have undergone surgery to cut the corpus callosum, the main bundle of neuronal fibres connecting the two sides of the brain. Input from the left field of view is processed by the right hemisphere and vice versa. Left hemisphere Visual fields Corpus callosum Right hemisphere A word is flashed briefly to the right field of view, and the patient is asked what he saw. Face • FACE Because the left hemisphere is dominant for verbal processing, the patient's answer matches the word. Now a word is flashed to the left field of view, and the patient is asked what he saw. FACE. Nothing The right hemisphere cannot share information with the left, so the patient is unable to say what he saw, but he can draw it. ● Neural Pathways & Neuroplasticity o Neural pathways - specialized nerve fibers (often found in the brain or connecting the brain to other parts of the brain) that coordinates a specific behavior/function Neuroplasticity - the process of a neural pathway changing with experience o ■ Rapid transfer of impulses when used frequently ■ Repeated use leads to an increase of neurotransmitters and then more NT receptors develop at the synapse ■ Examples of Neuroplasticity: writing, texting, board games, sports, dance, language and verbal communication ● The Endocrine and Nervous System o Pituitary gland: master gland that secretes hormones that activate other glands and Growth Hormone O Pineal gland: secretes melatonin and regulates sleep/wake cycle O Adrenal gland: secretes adrenaline (elevates bodily functions in stressful situations) and noradrenaline (increase alertness/focus) ● Fight or flight response (involves nervous/endocrine system) O Automatic physiological response to a perceived threat o Purpose of physical/physiological changes is to prepare body to confront/flee from a threat o Response is activated by sympathetic nervous system (hypothalamus & amygdala) o Brain Imaging techniques o Provide psychologists and professionals with info and images of the brain. o EEG or electroencephalogram: electrodes used to measure and record fluctuations in the brain's neural activity. ■ Displayed as brain wave patterns o CT, CAT, Computerized Axial Tomography: combines a series of X-ray images taken from different angles around the body to create a more detailed image. PET scans; Positron Emission Tomography: dyed tracers that highlight brain activity (warm colors are active; cool colors are not active) MRI - Magnetic Resonance Imaging: Magnetic fields used to create highly detailed images of the brain ■ Functional MRIs also measure changes in blood flow within certain brain regions ● Used to indicate active parts of the brain during a certain activity O O ■ Nervous system impulses are secreted into the bloodstream more rapidly than the endocrine system hormones Afterwards-> "rest and digest" reaction; body calms down ● The Biological Aspects of Sleep o The Circadian Rhythm: 24hr cycle during which the body's biological functions fluctuate ■ Regulated by the hypothalamus ■ Sleep/wake cycle controlled by pineal gland and melatonin hormone- induces sleep ■ Environmental conditions: sunlight exposure suppresses melatonin secretion o Jet lag: interruption of the sleep wake cycle when the circadian rhythm and sunlight are not synchronized ● The Sleep Cycle O Pattern of changes experienced during an 8 hour period of sleep O EEG records alpha waves of the cycle O Consist of 5 stages that repeat throughout the night ■ Have unique physiological and neurological changes Stage 1- Hypnagogia ■ Transition from wakefulness to sleep state ■ Hypnagogic sensations: Hallucinations that occur during the transition into a sleep state O Stage 2- Light Sleep O ■ Body functions and neural activity (thalamus) slows down ■ Limits sensory info sent to brain's sensory regions O Stage 3 and 4-Deep Sleep ● O ● ■ ■ Difficult to wake a person from Most physical restoration occurs . Growth hormone secreted O Immune system replenished ● Damaged tissue is repaired Stage 5- REM Sleep (rapid eye movement) O ● ■ Dreaming occurs ■ o Sleep Research by William Dement ■ ■ Placed research participants in a sleep lab to see how long people would sleep in a circadian rhythm (total sleep duration=8 hours) • Sleep Debt- the cumulative effect of getting insufficient amounts of sleep O Leads to changes in sleep cycle; REM state begins earlier and leads to impaired immune system function Sleep-Wake Disorders- disorders that affects the quality of sleep o Narcolepsy: marked by excessive and overwhelming daytime drowsiness and lapsing into sleep ■ Sudden loss of muscle tone; triggered by strong emotions ■ Experience of hallucinations due to hypnagogic sensations or sudden onset of REM sleep Sleep paralysis: a temporary inability to use voluntary muscles and limits reactions to dream content Leading authority on sleep, the effects of insufficient sleep and sleep disorders Obstructive Sleep Apnea: marked by airway constriction, during sleep, that interrupts normal breathing ■ caused by obesity treatment- prescription of a C-PAP; a breathing mask that delivers pressurized air to keep airways open Insomnia: difficulty initiating or maintaining sleep ■ Caused by anxiety or stress ■ Sleep disturbances cause significant distress and/or impair daily routine O REM sleep behavior disorder: dream enacting behaviors ■ Repeated episodes of vocalizing or performing complex behaviors during REM Sleep I Parasomnias- sleep walking and talking episodes common in younger children and linked to sleep anxiety The Dream State O The psychoanalytic (Freudian) Perspective on dreams ■ 1900: Freud published "On the Interpretation of Dreams O "A fulfillment of wishes" O ■ Dreams are meaningful because they allow the dreamer to act upon their unconscious impulses • Contemporary Dream Theories: O Dreams provide insight into the unconscious mind "dreams are the royal road to the unconscious..." Dreams consist of two components: Manifest Content: The imagery, sounds and story content of a dream ■ Latent Content: The unconscious impulses, fears, and anxieties that the manifest content represents • The interpretation meaning of the manifest content ● Discusses a recurring/significant dream and it's latent content O Activation-Synthesis Theory: ■ Aka Hobson-McCarley Theory: is based on studies done by James Hobson and Robert McCarley in 1977 ■ Neurons of the pons erratically produce impulses during REM sleep O ■ These impulses activate a random regions of the cerebral cortex, causing a wide range of thoughts and sensations Pons: "A dream state generator" ■ ■ Activation- Information Mode Model (The AIM) This theory explains the random nature of dreams ■ A 2000 update by James Hobson to his synthesis theory ■ Like older theory, pons produces erratic neural activity during REM stage Update -> The regions of the cerebral cortex activated by the pons, are those used most recently ■ Explains dreams with meaningful content Effects of Psychoactive Drugs O Produce changes in body chemistry, conscious, perception, awareness and mood O Two classifications of drugs: ■ Agonist mimic the effect of neurotransmitters ■ Antagonist block neurotransmitters from bonding with receptors sites O Stimulants: caffeine, cocaine, amphetamines, nicotine, methamphetamine Elevates mental & physical functioning by enhancing the function of the sympathetic nervous system and brain ■ Varying degrees of euphoric effect o Depressants: alcohol,barbiturates, rohypnol ■ Slow down mental & physical functioning of the central nervous system Hallucinogens: Marijuana, LSD, ecstasy ■ Alter perceptions of reality by causing the brain to misinterpret sensory info ■ Can induce delusional thoughts and hallucinations o Opiates: morphine, heroin ■ Decrease sensitivity to pain by enhancing effectiveness of endorphins Addiction is the body's dependence on the chemical properties of the drug ■ The neural pathway linked to pleasurable and gratifying sensations Can activate the dopamine reward pathway O Dendrites of dopamine pathway become thicker and less responsive o Withdrawal: physical symptoms experienced when drug use is discontinued ■ Symptoms vary: shakes, sweats, nausea, migraines, etc. ■ alter the function of a particular neural pathway and varied brain regions • Psychological Dependence o Use the behavioral approach in the concept of confirmation bias to explain how this belief develops: This belief can develop because of experienced- based learning ■ ● A positive experience, in a person's past may be attributed to drug use encouraging that person to continue This belief can develop because of confirmation bias: • A person may selectively recall positive experiences associated with drug use not the negative experiences