Drugs and Their Effect - The Human Brain - PDF

“DRUGS AND THEIR EFFECT” Examples: PSYCHOACTIVE DRUGS LSD (lysergic acid diethylamide) - induce sensory ➔ are substances that, when taken...

“DRUGS AND THEIR EFFECT” Examples: PSYCHOACTIVE DRUGS LSD (lysergic acid diethylamide) - induce sensory ➔ are substances that, when taken in or distortions that are not exactly hallucinations in the administered into one's system, affect mental usual sense, because the person generally processes, e.g. perception, consciousness, recognizes that the strange sensory experience is cognition or mood, and emotions. not real. MDMA (methylenedioxymethamphetamine) - Agonist - a drug that increases activity at a popularly known as ecstasy. synapse - Many young adults use MDMA at parties to - Based on the Greek word for “contestant” or increase their energy. However, as the drug wears “fighter” off, people feel depressed and lethargic. Antagonist - a drug that decreases activity at a synapse DEPRESSANTS - From the Greek word for an “enemy” Depressants are drugs that decrease arousal, such as alcohol and anxiolytics (anxiety-reducing STIMULANTS drugs). Stimulants are drugs that increase energy, Alcohol is a class of molecules that includes alertness, and activity. methanol, ethanol, propyl alcohol (rubbing Stimulant drugs increase activity levels and alcohol), and others. Ethanol is the type that pleasure by increasing the release and decreasing people drink. reuptake, of dopamine and certain other Anxiolytic drugs or tranquilizers help people relax. neurotransmitters. The most common examples are The behavioral effects of stimulant drugs depend benzodiazepines. Benzodiazepines calm people on the dose. Low levels enhance attention. At by facilitating transmission at inhibitory synapses. higher dose lead to confusion, impaired attention, and impulsiveness. NARCOTICS Narcotics are drugs that produce drowsiness, Examples: insensitivity to pain, and decreased Cocaine - It has long been available in the responsiveness. powdery form of cocaine hydrochloride, which can Opiates are either natural drugs derived from the be sniffed. opium poppy or synthetic drugs with a chemical Methylphenidate (Ritalin) - A drug often prescribed structure resembling natural opiates. Opiate drugs for attention deficit disorder, works the same way bind to endorphin receptors in the nervous system. as cocaine, at the same synapses. The immediate effect of opiates is pleasure and Tobacco delivers nicotine, which increases relief from pain. wakefulness and arousal by stimulating synapses Morphine (named after Morpheus, the Greek god responsive to the neurotransmitter acetylcholine. of dreams) has important medical use as a painkiller. HALLUCINOGENS The discovery of neurotransmitter receptors Drugs that induce sensory distortions. Often refers demonstrated that opiates block pain in the brain, as, psychedelics. not in the skin. Many of these drugs are derived from mushrooms or plants, and others are manufactured. MARIJUANA Also sometimes produce sudden emotional Marijuana (cannabis) is difficult to classify. changes, a dreamlike state, or a mystical Marijuana has several potential medical uses. experience.  The active ingredient in marijuana is THC or OCCIPITAL LOBE tetrahydrocannabinol. Located at the very back of the skull, and Marijuana acts on receptors on the presynaptic processes visual information. neuron, putting the brakes on release of both Cortical blindness - the usual kind of blindness excitatory and inhibitory transmitters. resulting from eye damage. Blindsight - the ability to point to or otherwise “THE HUMAN BRAIN” indicate the direction to a visual stimulus, without any conscious perception of seeing anything at all. 1. You use all of your brain. You may have heard that “they say” we use only 10 percent of our brains. TEMPORAL LOBE 2. The concept of monism, the idea that mental Located at the sides of the brain and responsible activity and brain activity are inseparable. for hearing, language, and integrating vision and According to monism, mental activity is brain audition. activity. The temporal cortex is also important for feeling something with your fingers and detecting the rate MAJOR PARTS OF THE NERVOUS SYSTEM of vibration. Central Nervous System (CNS) - consists of the Fusiform gyrus - an area in temporal lobe that brain and spinal cords, communicates with the rest responds mainly to the sight of faces. of the body by the peripheral nervous system. Motion blind: Although they see the size, shape, Peripheral Nervous System (PNS) - consisting of and color of objects, they do not track speed or nerves connecting the spinal cord with the rest of direction of movement. the body. Amygdala - a structure in the temporal lobe, 1. Somatic nervous system - connects to the skin responds strongly to emotional situations. and muscles; has voluntary control of skin, bones, joints, and skeletal muscle. PARIETAL LOBE 2. Autonomic nervous system - connects to the Located from the middle to the back of the skull, heart, stomach, and other organs; has involuntary and responsible primarily for processing control of internal organs, blood vessels, smooth information about touch and taste. and cardiac muscles. Primary somatosensory cortex - the primary site for touch sensations, also activates other areas THE CEREBRAL CORTEX that are important for emotional responses. ➔ The outer covering of the forebrain, and is Parietal lobe damage also interferes with spatial especially prominent in humans. attention. 3 Main Divisions of the Brain: FRONTAL LOBE 1. Forebrain - handles higher cognitive functions. Located behind the forehead and responsible 2. Midbrain - controls motor movement and sensory primarily for thinking, memory, and judgement. processing. Primary motor cortex, important for controlling fine 3. Hindbrain - manages coordination, balance, and movements, such as moving a finger or wiggling a autonomic functions. toe. Prefrontal cortex - important for memory of what LOBES OF THE CEREBRAL CORTEX has just happened and what you are planning to 1. Frontal Lobe do next. The prefrontal cortex is also critical for 2. Parietal Lobe directing attention. 3. Temporal Lobe Mirror neurons are active when you make a 4. Occipital Lobe movement and also when you watch someone else make a similar movement. THE TWO HEMISPHERES AND THEIR CONNECTIONS Cerebellum - “little brain”; its main function is to The left hemisphere controls speech, coordinate voluntary movement. comprehension, arithmetic, and writing. The right hemisphere controls creativity, spatial ability, The Autonomic Nervous System and Endocrine System artistic, and musical skills. The autonomic nervous system, closely The two hemispheres constantly exchange associated with the spinal cord, controls the heart, information through corpus callosum. Corpus digestive system, and other organs. callosum is a set of axons that connect the left and 1. Sympathetic - controlled by a chain of cells lying right hemispheres of the cerebral cortex just outside the spinal cord, increases heart rate, breathing rate, sweating, and other processes that MEASURING BRAIN ACTIVITY are important for vigorous fight-or-flight activities. Electroencephalograph (EEG) - uses electrodes 2. Parasympathetic - controlled by cells at the top on the scalp to record rapid changes in brain and bottom levels of the spinal cord, decreases electrical activity. heart rate, increases digestive activities. Magnetoencephalography (MEG) - records magnetic changes. Endocrine system - glands that produce Positron-emission tomography (PET) - records hormones and release them into the blood. the radioactivity of various brain areas emitted Hormones - chemicals released by glands and from injected chemicals. Red indicates areas of conveyed by the blood to alter activity in various greatest activity, followed by yellow, green, and organs. blue. Unfortunately, PET scans require exposing the brain to radioactivity. EXPERIENCE AND BRAIN PLASTICITY functional magnetic resonance imaging (fMRI) Plasticity - refers to the brain’s ability to change - uses magnetic detectors outside the head to its structure and function in response to compare the amounts of hemoglobin with and experience or damage. without oxygen in different brain areas. - change as a result of experience. SUBCORTICAL AREAS SOCIAL NEUROSCIENCE Thalamus - the egg-shaped structure above the The study of the biological bases of social brain stem; serves as a relay station for almost all behavior. information that comes and goes to the cortex. Oxytocin - A hormone also known as “love Limbic System - a brain region largely hormone” or “love-magnifying” hormone. responsible for memories and emotions, including - Oxytocin increased love that was already present, our responses to reward and punishment. but it didn’t create new love. Hypothalamus - It plays a role in controlling behaviors such as hunger, thirst, sleep, and sexual BINDING PROBLEM response. It also regulates body temperature, A theoretical problem that researchers first began blood pressure, emotions, and secretion of to notice around 1990. hormones. The question of how separate brain areas combine Medulla - The area of the brain stem that controls forces to produce a unified perception of a single heart rate and Breathing. object. Pons - The spherical shape above the medulla; it is important to sleep and arousal Spinal Cord - Controls many reflexes, such as the knee-jerk reflex. A reflex is a rapid, automatic response to a stimulus.