Exam 1 Study Guide PDF

Exam I – Study Guide 1. Steps of the Perceptual Process Slides: Ch. 1, Slides 12-13 Step 1: Environmental/Distal Stimulus – Any object in the environment available to be perceived. i.e. trees, buildings, birds chirping, smells in the air...

Exam I – Study Guide 1. Steps of the Perceptual Process Slides: Ch. 1, Slides 12-13 Step 1: Environmental/Distal Stimulus – Any object in the environment available to be perceived. i.e. trees, buildings, birds chirping, smells in the air Step 2: Proximal Stimulus – The specific object an observer focuses on. The pattern of light that lands on the retina, because it is “in proximity” to the receptors. The distinction between the distal stimulus (Step 1) and the proximal stimulus (Step 2) illustrates both transformation and representation. The distal stimulus (the tree) is transformed into the proximal stimulus, and this image represents the tree in the person’s eyes. Step 3: Receptor Processes/ Transduction – Conversion of light into electrical signals by photoreceptors in the retina. Step 4: Neural Processing – The transmission of these signals through the optic nerve to the brain. Step 5: Perception – The conscious awareness of the stimulus. Step 6: Recognition – Classifying or identifying what the stimulus is (e.g., recognizing a face). Step 7: Action – Responding to or interacting with the stimulus, such as picking up an object. 2. Elements of Signal Detection Theory Slides: Ch. 1, Slides 46-50 Criterion: The point at which the observer decides whether a stimulus is present. Sensitivity (d’): The observer's ability to distinguish the signal from noise. Outcomes: o Hit: Detecting the signal correctly. o Miss: Failing to detect the signal. o False Alarm: Detecting a signal when none is present. o Correct Rejection: Correctly identifying that no signal is present. ROC Curve: Graph showing the trade-offs between hit rate and false alarm rate. The shape of the ROC curve is determined by sensitivity. A person with higher sensitivity will have a more bowed curve, showing high hit rates with low false-alarm rates. o d’ (d-prime): Measures sensitivity by calculating the separation between noise and signal-plus-noise distributions. Higher sensitivity means a larger d’, which results in a more bowed ROC curve. 3. Recognition Slides: Ch. 1, Slide 16 Recognition: Involves matching a perceived stimulus to stored knowledge or memory. o Recognition is part of the perceptual process, which follows perception and is often influenced by top-down processing (knowledge-based processing). 4. Psychophysical Methods Measuring the quantitative relationships between the stimulus and perception. Fechner’s classical psychophysical methods for determining the absolute threshold of a stimulus are the method of limits, constant stimuli, and adjustment. Method of Limits: Stimulus intensity is increased or decreased until the observer changes their response. It is often used to find both absolute thresholds (minimum stimulus detectable) and difference thresholds (the smallest detectable difference between two stimuli). Method of Constant Stimuli: Randomized presentation of stimuli of varying intensities, some above and some below the threshold.  Method of Adjustment: The observer adjusts the stimulus intensity until they can just detect it. The person who is being tested is in charge of adjusting the intensity. Method Control Speed Accuracy Bias Potential Experimenter- Moderate Method of Limits Moderate Reliable controlled (anticipation/habituation) Method of Experimenter- Highly Slow Low (random presentation) Constant Stimuli controlled reliable Method of Subject- Less Fast High (subject variability) Adjustment controlled reliable 5. Difference Threshold Difference Threshold (Just Noticeable Difference, JND): The smallest difference between two stimuli that can be detected 50% of the time. The minimum amount of change necessary to detect a difference in two stimuli. Weber’s Law: The JND is a constant ratio of the original stimulus intensity. 6. Magnitude Estimation Slides: Ch. 1, Slide 45 Magnitude Estimation: Participants assign numbers to stimuli based on their perceived intensity. o Three possible relationships: ▪ Linear: Perceived magnitude is proportional to stimulus intensity. i.e. brightness of light increasing 10% each intensity, increasing proportionally. ▪ Response Compression: Perception increases at a slower rate than the stimulus. This means that as the stimulus becomes more intense, the observer’s perception does not increase as quickly. In other words, a large increase in the physical intensity of the stimulus results in only a small increase in perceived intensity. i.e. a light’s brightness may not show much difference if it is maxed to the human eye. ▪ Response Expansion: Perception increases faster than the stimulus. i.e. Electric shock, pain, fear signals, perception is more than double the stimulus intensity. 7. Transduction Transduction: The process by which photoreceptors (rods and cones) convert light into electrical signals in the retina. o Rods: Sensitive to low light, important for night vision. o Cones: Responsible for color vision and visual acuity. 8. Action Potentials Action Potential: An electrical signal generated by the movement of ions (Na+, K+) across the neuron’s membrane, a rapid, temporary change in the electrical charge across a neuron’s membrane, allowing it to send signals down its axon. 1. Resting Potential State: The neuron is at rest, not transmitting any signals. Membrane Potential: The inside of the neuron is negatively charged relative to the outside, typically around -70 mV. Ions: o Sodium (Na⁺): Concentrated outside the cell. o Potassium (K⁺): Concentrated inside the cell. o Chloride (Cl⁻) and proteins (which carry negative charges) are also more concentrated inside the cell. Key Element: The sodium-potassium pump (Na⁺/K⁺ pump) actively maintains this resting potential by pumping 3 Na⁺ out of the neuron and 2 K⁺ into the neuron using ATP. 2. Threshold and Depolarization Stimulus: If the neuron receives a sufficient stimulus, it triggers the opening of voltage-gated sodium channels. Threshold: A critical membrane potential (around -55 mV) must be reached for the action potential to initiate. Depolarization: Once the threshold is crossed, many sodium channels open, allowing Na⁺ ions to rush into the neuron. Effect: The influx of positive Na⁺ ions causes the inside of the neuron to become more positive, rapidly raising the membrane potential to about +40 mV. 3. Repolarization State: After the neuron reaches the peak of depolarization, the sodium channels close, and voltage-gated potassium channels open. Repolarization: K⁺ ions flow out of the cell, returning the inside of the neuron to a negative charge. Effect: The membrane potential starts to drop back toward the resting level. 4. Hyperpolarization (Undershoot) State: The potassium channels stay open a little longer than needed, causing the membrane potential to go below the resting potential (more negative than -70 mV). Effect: This is called hyperpolarization or the undershoot, where the cell is less likely to fire another action potential immediately. 5. Return to Resting Potential Recovery: The potassium channels close, and the sodium-potassium pump works to restore the membrane to its resting potential (-70 mV) by actively pumping Na⁺ out and K⁺ back in. Refractory Period: During this time, the neuron cannot initiate another action potential, ensuring that action potentials only travel in one direction along the axon. Ions Involved in Action Potentials 1. Sodium (Na⁺): o Moves into the neuron during depolarization. o Causes the inside of the cell to become more positive. 2. Potassium (K⁺): o Moves out of the neuron during repolarization and hyperpolarization. o Restores the negative charge inside the neuron. 3. Chloride (Cl⁻): o Maintains the overall balance of charge but plays a more passive role compared to Na⁺ and K⁺. Key Characteristics of Action Potentials: 1. Propagated Response: o Once an action potential is triggered, it travels down the axon without losing strength, ensuring the signal reaches its target. 2. Stimulus Intensity and Firing Rate: o While the size of an action potential remains constant, increasing the intensity of the stimulus can cause neurons to fire action potentials more frequently (increase in firing rate). 3. Refractory Period: o There is a brief period after an action potential during which the neuron cannot fire another action potential. This is the refractory period, which helps ensure the action potential only travels in one direction and sets a limit on how frequently a neuron can fire. 4. Spontaneous Action Potentials: o Some neurons may generate action potentials spontaneously, even without an external stimulus. These spontaneous firings help regulate ongoing neural activity. 9. “Grandmother” Cell The “Grandmother” Cell is a hypothetical neuron that responds to a highly specific stimulus, such as a person’s grandmother. This is part of specificity coding, where individual neurons are thought to represent specific objects. 10. Modularity (FFA, PPA, EBA) Brain modules can be studied in neurologically normal humans using techniques like brain imaging. This allows researchers to explore the brain's activity and function. Inferior Temporal (IT) Gyrus: This part of the brain is involved in visual object recognition. Damage to the fusiform face area (FFA) in the temporal lobe can result in prosopagnosia, a condition where individuals cannot recognize faces. Medial Temporal Lobe (MTL): The MTL is crucial for memory. Case studies, such as the famous H.M. case, highlight the role of MTL structures in memory formation and recall. Fusiform Face Area (FFA): Specializes in face recognition. Parahippocampal Place Area (PPA): Specializes in processing scenes and spatial layouts. Extrastriate Body Area (EBA): Responds to images of human bodies and body parts. 11. Specificity, Population, Sparse Coding Specificity Coding: A single neuron represents a specific object. This theory suggests that specific neurons are activated at the cortical level to respond to particular stimuli. But this theory has limitations, as it would require too many neurons to account for the vast number of objects we can recognize. Population Coding: The pattern of firing across many (large) neurons represents an object. Sparse Coding: A small number of neurons represent the object, with each neuron involved in representing multiple objects. Where recognition of objects is based on the pattern of firing across groups of neurons, rather than relying on just one specific neuron. This theory suggests that only a small number of neurons (a "sparse" pattern) are activated in response to a particular object, allowing for efficient processing of complex stimuli. 12. Diseases of the Eye Presbyopia: Age-related difficulty in focusing on close objects. Myopia: Nearsightedness; the eyeball is too long, causing distant objects to appear blurry. Hyperopia: Farsightedness; the eyeball is too short, making nearby objects hard to focus on. Retinitis Pigmentosa (RP): A group of genetic disorders that affect the retina and lead to a gradual decline in vision. o Symptoms: It typically starts with night blindness and a loss of peripheral vision. Over time, it can cause tunnel vision and, in some cases, total blindness. o Progression: The condition worsens slowly, and there is no cure, but treatments may slow the progression. Macular Degeneration: This condition affects the macula, which is the central part of the retina responsible for sharp central vision. o Symptoms: It leads to the loss of central vision, which can affect tasks like reading or recognizing faces. Peripheral vision usually remains intact. 13. Accommodation Accommodation: The process by which the lens changes shape to focus light on the retina. The lens becomes thicker to focus on near objects and thinner for distant objects. o When focusing on a near object, the lens becomes thicker to bend light more sharply, ensuring the object is focused on the retina. o For distant objects, the lens flattens to reduce the amount of bending required. 14. Parts of the Eye Cornea: Provides most of the eye's focusing power. Lens: Adjusts its shape to focus light on the retina (accommodation). Retina: Contains rods and cones for detecting light. Optic Nerve: Transmits visual information from the retina to the brain. 15. Convergence Convergence in the eye refers to the process where multiple photoreceptor cells (rods or cones) send signals to a single retinal ganglion cell. This pooling of information allows for the integration of signals from multiple sources and plays a crucial role in balancing sensitivity and acuity (sharpness of vision). Key Concepts of Convergence: 1. High Convergence (mostly in rods): o Rods exhibit high convergence, where many rods connect to a single ganglion cell. o Advantage: This high convergence increases sensitivity to light. It helps us see in low-light conditions because signals from many rods are combined to create a stronger overall signal. o Disadvantage: High convergence reduces acuity. Since many rods contribute to the same output signal, the brain cannot pinpoint exactly which rod was stimulated, leading to a loss of detail in vision. 2. Low Convergence (mostly in cones, especially in the fovea): o Cones, particularly those in the fovea (the central part of the retina responsible for sharp vision), exhibit low convergence, with only one or a few cones connecting to a single ganglion cell. o Advantage: Low convergence leads to higher acuity (sharp vision) because each cone’s signal remains distinct, allowing the brain to detect fine details.  o Disadvantage: Low convergence results in lower sensitivity to light because fewer signals are combined, making it harder to see in dim light. Trade-off Between Sensitivity and Acuity: More convergence (rods): Greater sensitivity, but lower detail (acuity). Rods are ideal for night vision but not for detailed tasks. Less convergence (cones): Greater visual detail, but lower sensitivity. Cones are best for daylight and color vision, providing sharp details but requiring more light to function effectively. Example: In a dark room, rods with high convergence allow you to detect movement or objects, but you won't see fine details. In bright light, cones with low convergence allow you to read fine print or see vibrant colors with high precision, but they struggle in low light. In summary, convergence in the eye allows for a balance between sensitivity to light and sharpness of vision, with rods favoring sensitivity and cones favoring acuity. 16. Dark/Light Adaptation Dark Adaptation: The process by which the eyes become more sensitive to low light after being in darkness. Rods regenerate photopigments during dark adaptation. This is measured using a dark adaptation curve, showing how rods and cones contribute to increased sensitivity over time. Light Adaptation: The eye adjusts to bright light by reducing sensitivity. Visual Pigment Molecules: In the retina, photoreceptors (rods and cones) contain opsin (a protein) and retinal (a light-sensitive molecule). Together, they form visual pigment molecules. Visual Transduction: This process occurs when retinal absorbs a photon of light, changing its shape in a process called isomerization, which triggers a cascade of chemical reactions. This converts light into electrical signals that are sent to the brain. Regeneration: After light exposure, retinal and opsin must recombine to make the photoreceptors responsive to light again. o In short, transduction is how light becomes electrical signals, while dark adaptation helps the eye adjust to low light conditions. 17. Organization of Retinal Layers o Five Major Cell Types in the Retina: o These include photoreceptors (rods and cones), bipolar cells, ganglion cells, and horizontal and amacrine cells. These different types of cells are responsible for processing and transmitting visual information to the brain. o The Vertical System: o The vertical system includes photoreceptors (rods and cones) and bipolar cells that directly pass visual information vertically through the retina, ultimately reaching ganglion cells, which send the signals to the brain. o The Horizontal System: o The horizontal system involves horizontal cells and amacrine cells, which integrate and modify the visual signals across different photoreceptors and ganglion cells, contributing to lateral inhibition (enhancing contrast in vision). o Convergence: o 120 rods converge onto a single ganglion cell, increasing sensitivity to light but reducing visual acuity.  o In contrast, 6 cones converge onto a single ganglion cell, providing sharper vision (higher acuity) but lower sensitivity to light. In summary, the vertical system focuses on direct pathways from photoreceptors to ganglion cells, while the horizontal system integrates signals across the retina. More rods converge onto a single ganglion cell than cones, contributing to the differences in sensitivity and acuity between these photoreceptors. 18. Double Dissociations Double Dissociations: Used to demonstrate that two functions (e.g., object recognition and spatial processing) rely on different neural pathways and can be independently impaired. It occurs when two individuals have damage to different brain areas that result in opposite impairments: o Person 1: Damage to Brain Area A impairs Function X (e.g., speech production) but leaves Function Y (e.g., comprehension) intact. o Person 2: Damage to Brain Area B impairs Function Y but leaves Function X intact. This pattern strongly suggests that the two functions are controlled by separate, independent neural systems, because the impairments can be reversed depending on the location of the brain damage. Example: ▪ One of the most famous examples of double dissociation is in language processing: ▪ Broca’s Aphasia: Damage to Broca’s area (in the frontal lobe) impairs speech production but leaves speech comprehension relatively intact. ▪ Wernicke’s Aphasia: Damage to Wernicke’s area (in the temporal lobe) impairs speech comprehension but leaves speech production (although often nonsensical) relatively intact. ▪ This double dissociation between Broca’s and Wernicke’s areas provides strong evidence that these two brain regions are specialized for different aspects of language processing. Importance of Double Dissociation: o It helps establish that two cognitive processes are independent of each other. o It provides stronger evidence than single dissociation alone because it shows that the functions are not just interdependent but also localized in different brain areas. 19. Organization of Visual Pathways Visual information travels from the retina to the Lateral Geniculate Nucleus (LGN) and then to the Primary Visual Cortex (V1). o Ventral Pathway (What): Processes object identity. o Dorsal Pathway (Where/How): Processes spatial location and motion. Path of Visual Information: 1. Light hits the retina, where it is processed by rods and cones. 2. Signals are sent via optic nerve to the Lateral Geniculate Nucleus (LGN). 3. From the LGN, signals move to the primary visual cortex (V1) in the occipital lobe. 4. Signals are further processed along two pathways: o Dorsal (Where): For spatial awareness and motion. o Ventral (What): For object recognition. Dorsal Pathway: Function: Known as the "where" pathway, it is responsible for processing motion, spatial location, and coordination of movements. Path: Starts in the magnocellular layers of the LGN and moves through V1, V2, and up into the parietal lobe. Damage to the Dorsal Pathway: Results in difficulties with spatial tasks, such as navigating through space or reaching for objects. Ventral Pathway: Function: Known as the "what" pathway, it is essential for object recognition and identifying visual details such as shape, color, and form. Path: Begins in the parvocellular layers of the LGN, travels through V1, V2, and into the inferior temporal cortex.  Damage to the Ventral Pathway: Leads to problems with recognizing objects (visual agnosia) or faces (prosopagnosia). Lobes of the Brain and General Organization: Occipital Lobe: Primary visual processing center, home to V1 and other visual areas. Temporal Lobe: Processes object recognition (ventral pathway), contains areas like the fusiform face area (FFA). Parietal Lobe: Processes spatial information and motion detection (dorsal pathway). Frontal Lobe: Involved in decision-making, motor functions, and integrating information from other lobes. Summary: Each lobe specializes in different cognitive processes, but they are interconnected to ensure integrated processing of visual and other sensory information. Feature Detectors: Simple Cells: Respond to specific orientations of bars or edges. Found in the primary visual cortex (V1). Complex Cells: Respond to bars of light in specific orientations moving in a particular direction. Found in V1 and V2. End-Stopped Cells: Respond to bars of light of a specific length, corners, or angles. Also found in V1 and V2. Importance: These cells are crucial for breaking down visual scenes into their fundamental components (lines, edges, and movement). Ocular Dominance Columns: Definition: Columns of neurons in the visual cortex that respond preferentially to input from one eye. Location: Found in V1. Function: Organizes visual input based on eye dominance, allowing integration of information from both eyes for depth perception (binocular vision). Neuroplasticity: Early visual experiences can alter ocular dominance columns, as seen in cases of monocular deprivation. Hypercolumns: Definition: A functional unit in the visual cortex that processes information from a small area of the visual field. Structure: Each hypercolumn contains a complete set of orientation columns and ocular dominance columns for both eyes. Function: They analyze multiple aspects of a visual stimulus, such as orientation, color, and depth, in parallel. Different Types of Agnosias: Visual Agnosia: Inability to recognize objects despite having intact vision. o Associative Agnosia: Patients can perceive objects but cannot assign meaning to them. o Apperceptive Agnosia: Patients have trouble perceiving the shape of objects. Prosopagnosia: Inability to recognize faces, typically due to damage to the fusiform face area (FFA) in the temporal lobe. Color Agnosia (Achromatopsia): Inability to perceive colors due to damage to the ventral pathway or V4 area. Flow of Information through the LGN: Layers: The LGN has six layers, with: o Magnocellular layers (1 & 2): Process motion and broad outlines. o Parvocellular layers (3-6): Process fine details and color. o Koniocellular layers: Handle additional color processing.  Function: The LGN acts as a relay station, receiving visual input from the retina and sending it to the primary visual cortex (V1). Properties of the Visual Cortex (V1, V2, V3, etc.): V1 (Primary Visual Cortex): o First cortical area to receive visual input. o Handles basic features like orientation, edges, and motion. o Retinotopic map: Preserves spatial layout of the retina. V2: Receives input from V1 and processes more complex patterns, including contours and textures. V3: Involved in processing dynamic forms (objects in motion). V4: Specialized for color processing and shape perception. MT/V5: Part of the dorsal stream, important for processing motion. Part II) Essay Question Examples: 1. Define “top-down” and “bottom-up” processing and discuss how the “rat-man” demonstration is used to exemplify the distinction between these two types of processing. Top-down processing refers to how our previous experiences, knowledge, and expectations influence our perception of sensory information. It is a cognitive process that starts from higher- level functions, like memory or expectations, and works its way down to influence how we interpret sensory stimuli. In contrast, bottom-up processing involves building a perception from the raw sensory input. It is data-driven and starts with the sensory receptors, with perception emerging from the combination of simple stimuli. In the Rat-Man demonstration, participants are shown an ambiguous figure that can either be seen as a rat or a man. Whether the figure is perceived as a rat or a man depends on prior exposure. If participants were first shown several images of animals, they were more likely to perceive the ambiguous figure as a rat (top-down processing), whereas if they were shown human faces beforehand, they were more likely to perceive it as a man. This experiment demonstrates how top- down processing uses context and expectations to influence perception. Meanwhile, bottom-up processing would involve the brain interpreting the sensory information from the ambiguous figure without preexisting expectations influencing the outcome. 2. List seven steps from a stimulus in the environment to an action by the perceiving individual, illustrating each step with an example. 1. Environmental Stimulus: This refers to any stimulus in the external environment that is available for perception. Example: A tree in a park. 2. Attended Stimulus: The object in the environment that the individual focuses on. Example: The individual focuses on a specific tree in the park. 3. Stimulus on the Receptors: The image of the attended object is projected onto the sensory receptors. Example: Light reflecting off the tree hits the retina of the eye. 4. Transduction: The conversion of the physical stimulus (light) into electrical signals. Example: The photoreceptors in the retina (rods and cones) convert the light into electrical signals. 5. Neural Processing: The electrical signals are processed and transmitted through the neural pathways to the brain. Example: The signals travel through the optic nerve to the lateral geniculate nucleus (LGN) and then to the visual cortex. 6. Perception: The individual becomes consciously aware of the stimulus. Example: The individual perceives the shape, size, and color of the tree. 7. Recognition: The individual identifies the object by matching it to stored knowledge. Example: The individual recognizes the object as a tree. 8. Action: The individual takes some action based on the perception and recognition. Example: The individual walks toward the tree to sit under it. 3. Describe how information would be represented under each of the following representational schemes: specificity coding, population coding, and sparse coding. Specificity coding suggests that a specific neuron or group of neurons respond to a particular stimulus. In this view, each object is represented by the firing of a single, highly specialized neuron (e.g., a "grandmother cell"). For example, a specific neuron would fire only when the individual sees their grandmother. Population coding posits that objects are represented by the pattern of activity across many neurons, rather than just one specific neuron. Each neuron may respond to different objects, but the particular pattern of firing across the population of neurons is unique to each object. For example, a large group of neurons would fire in a specific pattern to represent the image of a face. Sparse coding is a middle ground between specificity and population coding. In sparse coding, only a small subset of neurons within a larger population is active when representing a particular stimulus. These neurons might represent multiple stimuli, but the combination of active neurons is unique for each stimulus. For example, only a few neurons would activate when an individual recognizes a chair, but the same neurons might also be involved in representing other furniture. 4. Draw a graph (with appropriate axis labels) of the dark adaptation curve. Describe the methodology used to isolate the rod component of the curve and the cone component. A dark adaptation curve typically shows how sensitivity to light improves over time as an individual adapts to darkness. The y-axis would represent sensitivity to light (or its inverse, threshold), and the x-axis would represent time in darkness. Initially, cone cells dominate vision, and sensitivity increases rapidly for about the first 5-10 minutes. This is represented by the first part of the curve. However, cone sensitivity plateaus, and after about 10 minutes, rod cells begin to take over, leading to a further and slower increase in sensitivity, which continues for about 20-30 minutes. To isolate the rod component, participants are asked to look at stimuli presented in the periphery of their visual field, where rods are more concentrated. To isolate the cone component, a bright light stimulus is used initially to bleach the rods, allowing the cones to dominate perception in the early phase. 5. What is the “blind spot”? Discuss two reasons why we are not usually aware of the blind spot. The blind spot is the area on the retina where the optic nerve exits the eye. This region lacks photoreceptors (rods and cones), meaning no visual information can be detected in this area. As a result, there is a small portion of the visual field where we are technically "blind." Two reasons why we are not aware of the blind spot: 1. Filling-in mechanism: The brain "fills in" the missing information based on the surrounding context, effectively creating a seamless visual experience. 2. Binocular vision: Each eye has a blind spot, but the blind spots are in different areas of the visual field for each eye. When both eyes are open, the visual information from one eye compensates for the blind spot in the other eye. 6. Explain what Hubel and Wiesel’s research on simple cells revealed about ocular dominance. Hubel and Wiesel’s research identified simple cells in the visual cortex, which are neurons that respond maximally to specific orientations of edges or lines in the visual field. Their experiments demonstrated that different neurons in the visual cortex are selective for input from either the left eye or the right eye, a phenomenon known as ocular dominance. They found that neurons in ocular dominance columns in the visual cortex respond preferentially to input from one eye over the other. For example, neurons in some columns would respond more strongly to stimulation of the left eye, while neurons in other columns responded more strongly to stimulation of the right eye. This discovery revealed the organized, columnar structure of the visual cortex, with alternating columns representing input from the left and right eyes. Quiz 1-4 Questions: Question 1 Trying to read a note written by someone with poor handwriting involves: Answer: c. both top-down and bottom-up processing. Explanation: Reading involves both bottom-up processing (decoding individual letters and words) and top- down processing (using prior knowledge and expectations to interpret the unclear handwriting). Question 2 In the “Halle Berry” study, Quiroga et al. found that the Halle Berry neuron is best described as responding to what regarding Ms. Berry? Answer: b. Concept Explanation: The neuron in question responded to the concept of Halle Berry, whether it was her face, her name, or even her dressed as Catwoman, indicating that it processed the concept rather than just specific visual features. Question 3 An intern working with children who have difficulty grasping due to traumatic brain injury is most likely to ask: Answer: d. How do the children interact with the crayons? Explanation: The intern is observing the children's ability to interact with adapted crayons, focusing on motor skills rather than their descriptions or identification of the crayons. Question 4 According to Ludy Benjamin, if changes in physical stimuli always resulted in similar changes in perception of those stimuli: Answer: b. there would be no need for psychology. Explanation: If perception directly mirrored stimuli without cognitive interpretation, psychological processes like perception, learning, and memory wouldn't be necessary, making the study of psychology redundant. Question 5 What is a way to record the signal from a single neuron? Answer: d. A recording electrode and a reference electrode can measure the difference in charge. Explanation: Single-neuron activity can be recorded by measuring the electrical difference between a recording electrode placed near the neuron and a reference electrode. Question 6 What is the primary purpose of the cell body in a neuron? Answer: c. Holding the mechanism that keeps the cell alive. Explanation: The cell body contains the nucleus and essential organelles responsible for maintaining the neuron’s life and function. Question 7 Which type of coding occurs when a particular object is represented by a pattern of firing of only a small group of neurons, with most neurons remaining silent? Answer: a. Sparse Explanation: In sparse coding, only a small group of neurons fire in response to a stimulus, while most neurons remain inactive, allowing for efficient representation. Question 8 One of the important limitations of the knowledge derived from determining thresholds is that: Answer: b. perception includes far more than just what happens at the threshold. Explanation: Threshold-based studies only reveal the minimum detectable stimulus, but perception involves much more, including how stimuli are interpreted and experienced beyond detection. Question 9 What is necessary for the neural transmission and processing of information? Answer: b. Both inhibition and excitation Explanation: Neurons require a balance of inhibitory and excitatory signals to regulate information processing and maintain proper neural function. Question 10 Classical psychophysical methods opened the way for the founding of scientific psychology by providing methods to measure: Answer: b. an aspect of the mind. Explanation: Psychophysics allowed researchers to quantify mental processes like perception, laying the foundation for scientific psychology. Question 11 Graphing the response of a simple cortical cell results in the: Answer: d. orientation tuning curve. Explanation: A simple cortical cell responds best to specific orientations of a visual stimulus, resulting in an orientation tuning curve when its responses are graphed. Question 12 Converging circuits with excitation and inhibition are associated most closely with which step of the perceptual process? Answer: c. Neural processing Explanation: Neural circuits that include both excitation and inhibition shape how sensory information is processed during the neural processing stage of perception. Question 13 Convergence results in what changes in sensitivity and acuity? Answer: a. Increased sensitivity and decreased acuity Explanation: Convergence (especially in rod cells) increases sensitivity to light but reduces acuity because multiple photoreceptors feed into a single ganglion cell. Question 14 Rods and cones synapse with what type of cells? Answer: a. Bipolar Explanation: Rods and cones in the retina synapse with bipolar cells, which then transmit visual information to ganglion cells. Question 15 An electrode is placed in an orientation column that responds best to orientations of 45 degrees. The adjacent column of cells will probably best respond to orientations of: Answer: b. 40 degrees. Explanation: Adjacent orientation columns in the visual cortex respond to orientations close to the preferred one, likely around 40 degrees if the original response was to 45 degrees. Question 16 The isomerization of a single pigment molecule triggers what is best described as a: Answer: a. chain reaction. Explanation: When a pigment molecule isomerizes, it starts a chain reaction of chemical events that lead to the generation of an electrical signal in the photoreceptor. Question 17 When visual pigments become bleached, they are: Answer: c. detached from the opsin. Explanation: When visual pigments are bleached, the retinal molecule changes shape and detaches from opsin, rendering the pigment inactive until it regenerates. Question 18 Ganel et al. (2008) designed a modified visual illusion, in which line 1 appears to be longer than line 2, when, in reality, line 2 is longer. The results of this investigation reveal: Answer: c. that the illusion only affects ventral stream processing. Explanation: The visual illusion impacts the ventral stream, which is responsible for perception and recognition, but not the dorsal stream, which guides action. Question 19 The visual pigment molecules are contained in the: Answer: d. outer segments of the visual receptors. Explanation: Visual pigment molecules are found in the outer segments of rods and cones, where they absorb light and initiate the phototransduction process. Question 20 Using the techniques of both recording from neurons and ablation, researchers found that properties of the ventral and dorsal streams are established by two different types of what kind of cells in the retina? Answer: d. Ganglion Explanation: The ventral and dorsal streams are influenced by two types of ganglion cells: parvocellular cells (for the ventral stream) and magnocellular cells (for the dorsal stream).