Cognitive Psychology PDF

COGNITIVE PSYCHOLOGY JOHN MARK G. LAFAVILLA, RPM MAIN LESSON Cognitive Neuroscience is the field of study linking the brain and other aspects of the nervous system to cognitive processing and, ultimately, to behavior. The brain is the organ in our bodies that most directly co...

COGNITIVE PSYCHOLOGY JOHN MARK G. LAFAVILLA, RPM MAIN LESSON Cognitive Neuroscience is the field of study linking the brain and other aspects of the nervous system to cognitive processing and, ultimately, to behavior. The brain is the organ in our bodies that most directly controls our thoughts, emotions, and motivations (Gloor, 1997; Rockland, 2000; Shepherd, 1998). Localization of function refers to the specific areas of the brain that control specific skills or behaviors. The nervous system is the basis for our ability to perceive, adapt to, and interact with the world around us (Gazzaniga, 1995, 2000; Gazzaniga, Ivry, & Mangun, 1998).  COGNITION IN THE BRAIN: THE ANATOMY AND MECHANISMS OF THE BRAIN Gross Anatomy of the Brain: Forebrain. The forebrain is the region of the brain located toward the top and front of the brain. It comprises the cerebral cortex, the basal ganglia, the limbic system, the thalamus, and the hypothalamus. o The cerebral cortex is the outer layer of the cerebral hemispheres. It plays a vital role in our thinking and other mental processes. o The basal ganglia (singular: ganglion) are collections of neurons crucial to motor function.  COGNITION IN THE BRAIN: THE ANATOMY AND MECHANISMS OF THE BRAIN o The limbic system is important to emotion, motivation, memory, and learning. Ø Septum is involved in anger and fear; (Pleasure and Reward) Ø Amygdala plays an important role in emotion as well, especially in anger and aggression. (Stimulation of the amygdala commonly results in fear. ) Ø Hippocampus plays an essential role in memory formation  COGNITION IN THE BRAIN: THE ANATOMY AND MECHANISMS OF THE BRAIN o The thalamus relays incoming sensory information through groups of neurons that project to the appropriate region in the cortex. o The hypothalamus regulates behavior related to species survival: fighting, feeding, fleeing, and mating.  COGNITION IN THE BRAIN: THE ANATOMY AND MECHANISMS OF THE BRAIN Midbrain. The midbrain helps to control eye movement and coordination. The midbrain is more important in nonmammals where it is the main source of control for visual and auditory information. o Reticular activating system (also extends into the hindbrain) is important in controlling consciousness (sleep arousal), attention, cardiorespiratory function, and movement. The RAS also extends into the hindbrain. Both the RAS and the thalamus are essential to our having any conscious awareness of or control over our existence. The brainstem connects the forebrain to the spinal cord. It comprises the hypothalamus, the thalamus, the midbrain, and the hindbrain. o Superior colliculi (on top) involved in vision (especially visual reflexes). o Inferior colliculi (below) involved in hearing. o Gray matter, red nucleus, substantia nigra, ventral region is important in controlling movement.  COGNITION IN THE BRAIN: THE ANATOMY AND MECHANISMS OF THE BRAIN Hindbrain. The hindbrain comprises the medulla oblongata, the pons, and the cerebellum. o Medulla oblongata controls heart activity and largely controls breathing, swallowing, and digestion. (Autonomic functions) (Part of Brainstem) o Pons serves as a kind of relay station because it contains neural fibers that pass signals from one part of the brain to another. o Cerebellum (from Latin, “little brain”) controls bodily coordination, balance, and muscle tone, as well as some aspects of memory involving procedure-related movements  CEREBRAL CORTEX AND LOCALIZATION OF FUNCTION It forms a 1- to 3-millimeter layer that wraps the surface of the brain somewhat like the bark of a tree wraps around the trunk. In human beings, the many convolutions, or creases, of the cerebral cortex comprise three elements. Sulci (singular, sulcus) are small grooves. Fissures are large grooves. And gyri (singular, gyrus) are bulges between adjacent sulci or fissures. The cortex comprises 80% of the human brain (Kolb & Whishaw, 1990).  CEREBRAL CORTEX AND LOCALIZATION OF FUNCTION The surface of the cerebral cortex is grayish. It is sometimes referred to as gray matter. This is because it primarily comprises the grayish neural-cell bodies that process the information that the brain receives and sends. In contrast, the underlying white matter of the brain’s interior comprises mostly white, myelinated axons. The cerebral cortex forms the outer layer of the two halves of the brain—the left and right cerebral hemispheres  CEREBRAL CORTEX AND LOCALIZATION OF FUNCTION The left cerebral hemisphere is specialized for some kinds of activity whereas the right cerebral hemisphere is specialized for other kinds. The left hemisphere of the brain directs the motor responses on the right side of the body. The right hemisphere directs responses on the left side of the body. However, not all information transmission is contralateral—from one side to another (contra-, “opposite”; lateral, “side”). Some ipsilateral transmission—on the same side—occurs as well. The corpus callosum is a dense aggregate of neural fibers connecting the two cerebral hemispheres  WHAT FUNCTIONS IN THE BRAIN ARE CONTRALATERAL AND IPSILATERAL? CONTRALATERAL FUNCTIONS: 1. Motor Control: Primary Motor Cortex: The motor cortex in the left hemisphere controls movements of the right side of the body, and vice versa. This is known as contralateral motor control. Example: If you move your right hand, the left hemisphere of your brain is primarily responsible for initiating that movement. 2. Sensory Processing: Somatosensory Cortex: Similar to motor control, sensory information from one side of the body is processed by the opposite hemisphere. Example: Touch sensations from the right hand are processed in the left somatosensory cortex.  WHAT FUNCTIONS IN THE BRAIN ARE CONTRALATERAL AND IPSILATERAL? 3. Visual Processing: Visual Fields: The left visual field of both eyes is processed by the right hemisphere, and the right visual field of both eyes is processed by the left hemisphere. Example: If you see something in the left half of your visual field, the right hemisphere of your brain is primarily responsible for processing that visual information. 4. Auditory Processing: Auditory Pathways: While each ear sends auditory information to both hemispheres, there is a stronger projection from each ear to the opposite hemisphere. Example: Sounds heard by the right ear are predominantly processed by the left hemisphere.  WHAT FUNCTIONS IN THE BRAIN ARE CONTRALATERAL AND IPSILATERAL? IPSILATERAL FUNCTIONS: 1. Olfactory Processing: Olfaction (Smell): The sense of smell is unique in that it is processed ipsilaterally. The right nostril sends signals to the right hemisphere, and the left nostril sends signals to the left hemisphere. 2. Taste: Gustation (Taste): Taste signals are largely processed ipsilaterally, meaning taste information from the right side of the tongue is processed by the right hemisphere, and from the left side by the left hemisphere.  WHAT FUNCTIONS IN THE BRAIN ARE CONTRALATERAL AND IPSILATERAL? COMBINATION OF CONTRALATERAL AND IPSILATERAL FUNCTIONS: 1. Auditory Processing: Although each ear sends information to both hemispheres, it is predominantly contralateral. However, some degree of ipsilateral processing occurs as well, allowing for more complex processing of sounds. 2. Vision: Each eye sends information to both hemispheres, but in a contralateral manner. The right side of each retina (which captures the left visual field) sends information to the right hemisphere, while the left side of each retina (which captures the right visual field) sends information to the left hemisphere. 3. Language: Language Processing: In most people, especially right-handed individuals, language functions are largely lateralized to the left hemisphere, meaning that language production and comprehension typically occur in the left hemisphere, regardless of whether the input is from the left or right ear. LEFT BRAIN VS. RIGHT BRAIN MYTH The left hemisphere is purely for Logic while the Right hemisphere is for creativity One side of the brain is more dominant in each person.  HEMISPHERIC SPECIALIZATION The study of hemispheric specialization in the human brain can be traced back to Marc Dax, a country doctor in France. By 1836, Dax had treated more than 40 patients suffering from aphasia—loss of speech—as a result of brain damage. Dax noticed a relationship between the loss of speech and the side of the brain in which damage had occurred. In studying his patients’ brains after death, Dax saw that in every case there had been damage to the left hemisphere of the brain. In 1861, French scientist Paul Broca claimed that an autopsy revealed that an aphasic stroke patient had a lesion in the left cerebral hemisphere of the brain, identified, now called Broca’s area, contributes to speech. German neurologist Carl Wernicke, studied language-deficient patients who could speak but whose speech made no sense, now known as Wernicke’s area, which contributes to language comprehension.  HEMISPHERIC SPECIALIZATION Roger Sperry (1964) argued that each hemisphere behaves in many respects like a separate brain. In a classic experiment that supports this contention, Sperry and his colleagues severed the corpus callosum connecting the two hemispheres of a cat’s brain. They then proved that information presented visually to one cerebral hemisphere of the cat was not recognizable to the other hemisphere. Some of the most interesting information about how the human brain works, and especially about the respective roles of the hemispheres, has emerged from studies of humans with epilepsy in whom the corpus callosum has been severed. The left hemisphere is important not only in language but also in movement. People with apraxia— disorders of skilled movements—often have had damage to the left hemisphere. The right hemisphere is largely “mute” (Levy, 2000). It has little grammatical or phonetic understanding. But it does have very good semantic knowledge. It also is involved in practical language use. Gazzaniga (Gazzaniga & LeDoux, 1978) does not believe that the two hemispheres function completely independently but rather that they serve complementary roles.  LEFT BRAIN VS. RIGHT BRAIN ACCORDING TO GAZZANIGA The human brain does not favor one side over the other. The two sides work differently, but one side is not stronger than the other unless it’s damaged. Certain areas of the brain simply have stronger neural connections than others, which is what makes each of us better at certain skills – and those connections skills can be strengthened with practice.) We do not only use one side of our brain at a time. Both sides work in concert. For example, our left brain may do the heavy lifting with calculations, but our right brain helps with estimates and numerical comparisons.  LABELS OF CEREBRAL HEMISPHERES The four lobes, named after the bones of the skull lying directly over them (Figure 2.6), are the frontal, parietal, temporal, and occipital lobes. The frontal lobe, toward the front of the brain, is associated with motor processing and higher thought processes, such as abstract reasoning, problem solving, planning, and judgment (Stuss & Floden, 2003). The parietal lobe, at the upper back portion of the brain, is associated with somatosensory processing. The temporal lobe, directly under your temples, is associated with auditory processing and comprehending language. The occipital lobe is associated with visual processing (De Weerd, 2003b). The occipital lobe contains numerous visual areas, each specialized to analyze specific aspects of a scene, including color, motion, location, and form  LABELS OF CEREBRAL HEMISPHERES The terms rostral, ventral, caudal, and dorsal are anatomical directional terms used to describe the locations and orientations of structures within the body, particularly in the nervous system. These terms help in pinpointing specific areas in relation to each other. Rostral refers to the front part of the brain (literally the "nasal region"). Ventral refers to the bottom surface of the body/brain (the side of the stomach). Caudal literally means "tail" and refers to the back part of the body/brain. Dorsal refers to the upside of the brain (it literally means "back," and in animal's back is on the upside of the body).  NEURONAL STRUCTURE AND FUNCTION Individual neural cells, called neurons, transmit electrical signals from one location to another in the nervous system. Neurons vary in their structure, but almost all neurons have four basic parts, as illustrated in Figure  NEURONAL STRUCTURE AND FUNCTION o The soma, which contains the nucleus of the cell (the center portion that performs metabolic and reproductive functions for the cell), is responsible for the life of the neuron, and connects the dendrites to the axon. o The many dendrites are branch- like structures that receive information from other neurons, and the soma integrates the information. o The single axon is a long, thin tube that extends (and sometimes splits) from the soma and responds to the information, when appropriate, by transmitting an electrochemical signal, which travels to the terminus (end), where the signal can be transmitted to other neurons. Axons are of two basic, roughly equally occurring kinds, distinguished by the presence or absence of myelin. - Myelin is a white, fatty substance that surrounds some of the axons of the nervous system, which accounts for some of the whiteness of the white matter of the brain. Some axons are myelinated (in that they are surrounded by a myelin sheath). This sheath, which insulates and protects longer axons from electrical interference by other neurons in the area, also speeds up the conduction of information. - Nodes of Ranvier are small gaps in the myelin coating along the axon, which serve to increase conduction speed even more by helping to create electrical signals, also called action potentials, which are then conducted down the axon.  NEURONAL STRUCTURE AND FUNCTION o The terminal buttons are small knobs found at the ends of the branches of an axon that do not directly touch the dendrites of the next neuron. Rather, there is a very small gap, the synapse. -The synapse serves as a juncture between the terminal buttons of one or more neurons and the dendrites (or sometimes the soma) of one or more other neurons (Carlson, 2006). Ø Signal transmission between neurons occurs when the terminal buttons release one or more neurotransmitters at the synapse. These neurotransmitters are chemical messengers for the transmission of information across the synaptic gap to the receiving dendrites of the next neuron. o At present, it appears that three types of chemical substances are involved in neurotransmission: -Monoamine neurotransmitters are synthesized by the nervous system through enzymatic actions on one of the amino acids (constituents of proteins, such as choline, tyrosine, and tryptophan) in our diet (e.g., acetylcholine, dopamine, and serotonin); (Plays a major role in mood regulation, arousal and cognition) -Amino-acid neurotransmitters are obtained directly from the amino acids in our diet without further synthesis (e.g. GABA and Glutamate); (Inhibitory and Excitatory neurotransmitters) -Neuropeptides are peptide chains (modulate the effects of neurotransmitters e.g endorphins).  NEURONAL STRUCTURE AND FUNCTION Neurotransmitters Ø Acetylcholine is associated with memory functions, sleep, arousal and the loss of acetylcholine can lead to Alzheimer’s disease. Ø Dopamine is associated with attention, learning, and movement coordination. Dopamine also is involved in motivational processes, such as reward and reinforcement. Schizophrenics show very high levels of dopamine. Ø Serotonin plays an important role in eating behavior and body-weight regulation. High serotonin levels play a role in some types of anorexia. Serotonin is also involved in aggression and regulation of impulsivity (Rockland, 2000). Drugs that block serotonin tend to result in an increase in aggressive behavior. Ø GABA (gamma-aminobutyric acid) functions as the general neuromodulatory effects resulting from inhibitory influences on presynaptic axons. Currently believed to influence certain mechanisms for learning and memory (Izquierdo & Medina, 1997).  RECEPTORS AND DRUGS When people stop using the drugs, withdrawal symptoms arise. Once a user has formed narcotic dependence, for example, the form of treatment differs for acute toxicity (the damage done from a particular overdose) versus chronic toxicity (the damage done by long-term drug addiction). Acute toxicity is often treated with naloxone or related drugs. o Naloxone (as well as a related drug, naltrexone) occupies opiate receptors in the brain better than the opiates themselves occupy those sites; thus, it blocks all effects of narcotics. In fact, naloxone has such a strong affinity for the endorphin receptors in the brain that it actually displaces molecules of narcotics already in these receptors and then moves into the receptors. o In narcotic detoxification, methadone often is substituted for the narcotic (typically, heroin). Methadone binds to endorphin receptor sites in a similar way to naloxone and reduces the heroin cravings and withdrawal symptoms of addicted persons.  VIEWING THE STRUCTURES AND FUNCTIONS OF THE BRAIN Scientists can use many methods for studying the human brain. These methods include both postmortem (from Latin, “after death”) studies and in vivo (from Latin, “living”) techniques on both humans and animals. Each technique provides important information about the structure and function of the human brain. Postmortem Studies. Even today, researchers often use dissection to study the relation between the brain and behavior. In the ideal case, studies start during the lifetime of a person. Researchers observe and document the behavior of people who show signs of brain damage while they are alive (Wilson, 2003). Later, after the patients die, the researchers examine the patients’ brains for lesions—areas where body tissue has been damaged, such as from injury or disease.  VIEWING THE STRUCTURES AND FUNCTIONS OF THE BRAIN Studying Live Nonhuman Animals. To study the changing activity of the living brain, scientists must use in vivo research. Many early in vivo techniques were performed exclusively on animals. For example, Nobel Prize–winning research on visual perception arose from in vivo studies investigating the electrical activity of individual cells in particular regions of the brains of animals Studying Live Humans. An array of less invasive imaging techniques for use with humans has been developed. These techniques—electrical recordings, static imaging, and metabolic imaging. o Electrical Recordings. Electroencephalograms (EEGs) are recordings of the electrical frequencies and intensities of the living brain, typically recorded over relatively long periods (Picton & Mazaheri, 2003). EEGs are also used as a tool in the diagnosis of epilepsy because they can indicate whether seizures appear in both sides of the brain at the same time, or whether they originate in one part of the brain and then spread. An event-related potential (ERP) is the record of a small change in the brain’s electrical activity in response to a stimulating event.  VIEWING THE STRUCTURES AND FUNCTIONS OF THE BRAIN Static Imaging Techniques. Psychologists use still images to reveal the structures of the brain. The techniques include angiograms, computed tomography (CT) scans, and magnetic resonance imaging scans (MRI). Computed tomography (CT or CAT). Unlike conventional X-ray methods that only allow a two dimensional view of an object, a CT scan consists of several X-ray images of the brain taken from different vantage points that, when combined, result in a three-dimensional image. The aim of an angiography is not to look at the structures in the brain, but rather to examine the blood flow. When the brain is active, it needs energy, which is transported to the brain in the form of oxygen and glucose by means of the blood. The magnetic resonance imaging (MRI) scan is of great interest to cognitive psychologists. The MRI reveals high-resolution images of the structure of the living brain by computing and analyzing magnetic changes in the energy of the orbits of nuclear particles in the molecules of the body. There are two kinds of MRIs—structural MRIs and functional MRIs.  VIEWING THE STRUCTURES AND FUNCTIONS OF THE BRAIN Metabolic Imaging. Metabolic imaging techniques rely on changes that take place within the brain as a result of increased consumption of glucose and oxygen in active areas of the brain. The basic idea is that active areas in the brain consume more glucose and oxygen than do inactive areas during some tasks. Scientists attempt to pinpoint specialized areas for a task by using the subtraction method. This method uses two different measurements: one that was taken while the subject was involved in a more general or control activity, and one that was taken when the subject was engaged in the task of interest. By subtracting the brain activity measured during the control condition from that measured during the task condition, researchers can identify the brain regions specifically involved in the cognitive process. Example: Suppose researchers are studying brain activity associated with solving complex math problems. The control activity could be a task where participants look at a blank screen or view simple shapes on a screen without performing any calculations. This control activity provides a baseline level of brain activity that is not related to problem-solving. Example: The task of interest might involve participants solving complex mathematical equations. During this task, researchers would use metabolic imaging to observe which areas of the brain show increased activity (such as increased blood flow or glucose consumption) compared to the control activity.  VIEWING THE STRUCTURES AND FUNCTIONS OF THE BRAIN Positron emission tomography (PET) scans measure increases in oxygen consumption in active brain areas during particular kinds of information processing Transcranial magnetic stimulation (TMS) temporarily disrupts the normal activity of the brain in a limited area. Therefore, it can imitate lesions in the brain or stimulate brain regions. TMS requires placing a coil on a person’s head and then allowing an electrical current to pass through it (Figure 2.10).  BRAIN DISORDERS Stroke - vascular disorder is a brain disorder caused by a stroke. Strokes occur when the flow of blood to the brain undergoes a sudden disruption. People who experience stroke typically show marked loss of cognitive functioning. The nature of the loss depends on the area of the brain that is affected by the stroke. There may be paralysis, pain, numbness, a loss of speech, a loss of language comprehension, impairments in thought processes, a loss of movement in parts of the body, or other symptoms. Brain Tumors - also called neoplasms, can affect cognitive functioning in very serious ways. Tumors can occur in either the gray or the white matter of the brain. Tumors of the white matter are more common (Gazzaniga, Ivry, & Mangun, 2009). o Two types of brain tumors can occur. Primary brain tumors start in the brain. Most childhood brain tumors are of this type. Secondary brain tumors start as tumors somewhere else in the body, such as in the lungs. Head Injuries - injuries result from many causes, such as a car accident, contact with a hard object, or a bullet wound. Head injuries are of two types. In closed-head injuries, the skull remains intact but there is damage to the brain, typically from the mechanical force of a blow to the head. Slamming one’s head against a windshield in a car accident might result in such an injury. In open-head injuries, the skull does not remain intact but rather is penetrated, for example, by a bullet.