PSY 555 Exam 3 Essay Questions_Martha Ramsey (1)

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1 PSY 555 Exam 3 Essay Questions PSY 555 Exam 3 Essay Questions Answer each of the following 10 questions in no more than one paragraph each. Be sure to provide clear examples to support your points. Each question is worth 10 points. 1) Describe how the physical dimensions of light correspond to the psychological dimensions of light. The physical dimensions of light describe the properties of light that can be measured, such as intensity, angle of incidence, direction, and spectrum. On the other hand, psychological dimensions of light describe how these properties affect how we perceive

2 light. For instance, different intensities of light can create different moods, such as direct sunlight giving a feeling of energy and life. In contrast, dim, diffused light creates a more calming, relaxed atmosphere (Carlson & Birkett, 2021). Similarly, the direction of light impacts our perception. For instance, indirect lighting can make an otherwise small room appear larger and more inviting, while direct lighting can be harsh and overwhelming. All of these psychological dimensions of light are created through the physical properties of light, allowing us to understand how our perception of light can be improved or changed with adjustments to its physical dimensions. 2) Compare and contrast the visual functions of rods and cones. Rods and cones are photoreceptor cells within the retina that mediate the visual perception atmosphere (Carlson & Birkett, 2021). Rods, which are more plentiful in the retina than cones, are sensitive to low light levels and are responsible for black-and-white and peripheral vision. They contain only one type of pigment, rhodopsin, and provide sharp details when viewing a brightly illuminated object. Conversely, cones require more significant amounts of light to be activated and are largely responsible for color vision. They contain three pigments, red, green, and blue, which enable them to discriminate between three primary colors, red, yellow, and blue, and lead to the perception of all other colors. Together, the roles of rods and cones contribute to the richness and complexity of sight.

3 3) Explain how the receptor potential produced in a photoreceptor by light generates action potentials within the retina. The initial event that occurs when a photoreceptor is exposed to light generates a receptor potential. This electrical signal arises from changes in membrane ionic conductance in response to the influx of photons. In photoreceptors, depolarization of the membrane polarizes the receptor to some level of potential in direct proportion to the amount of light received. On the other hand, action potentials, also known as spike potentials, are similar to graded potentials in that they are propagated through neurons. Still, they differ in that they are discrete events resulting from a sudden, rapid, and significant membrane potential depolarization atmosphere (Carlson & Birkett, 2021). A large enough receptor potential in a photoreceptor will trigger an action potential by opening voltage-gated sodium channels. This allows an influx of sodium ions to enter the cell and cause a sudden and large enough depolarization, stimulating the opening of voltage-gated potassium channels. 4) Explain the organization of neurons into modules in the striate cortex. The striate cortex is a tightly organized area in the brain that receives visual information and is responsible for early visual processing. Neurons within V1 are organized into different functional modules, such as orientation-selective, direction-selective, and color- selective cells (Zeki & Leff, 2021). These neurons are also arranged so that each module forms a discrete column vertically and horizontally aligned with other modules. The

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4 organization of neurons into these modules helps the brain process visual information quickly and efficiently, allowing it to quickly detect patterns, recognize objects, and react to environmental changes. 5) Compare and contrast the anatomy and function of the dorsal and ventral streams. The dorsal and ventral streams refer to two distinct processing pathways in the visual system. The dorsal stream, the "where" pathway, is responsible for the special processing of visual stimuli and controlling body movement and navigation (Micheletti et al., 2021). This pathway starts in the primary visual cortex and passes through the parietal lobe and into the premotor cortex. The ventral stream, the "what" pathway, is responsible for object recognition and identification. It starts in the primary visual cortex and passes through the temporal lobe and into the inferior temporal cortex. While both streams are part of the same visual system, they are responsible for different functions. The dorsal stream processes visual data to guide movement, while the ventral stream recognizes objects, colors, and shapes (Micheletti et al., 2021). Anatomically, the two streams travel throughout different areas of the brain. For example, the dorsal stream passes through the parietal lobe and into the premotor cortex, while the ventral stream passes through the temporal lobe and into the inferior temporal cortex. 6) Compare and contrast the roles of the LH and VMH for the modulation of eating. The Lateral Hypothalamus (LH) and the Ventromedial Hypothalamus (VMH) play similar yet distinct roles in the modulation of eating. Both nuclei contain neurons directly

5 affected by hunger, satiety, and other internally- or externally derived signals, like stress, which modulate activity in the hypothalamus. The LH is mainly responsible for initiating and promoting eating, as its neurons are affected by hunger, signaling to the rest of the brain that food is needed. On the other hand, the VMH is responsible for inhibiting food intake. The VMH's neurons process signals about fullness, satiety, and other internal signals that signal to the brain that eating should be stopped (Carlson & Birkett, 2021). The LH is more sensitive to external cues than the VMH. While the LH is more sensitive to food's sight, smell, and taste, the VMH is more sensitive to internally driven factors, such as signals sent from the intestines. 7) Compare and contrast the roles of ghrelin and of cholecystokinin (CCK) for the control of eating. Ghrelin and cholecystokinin (CCK) are two hormones that have essential roles in regulating the body's behavior when it comes to eating. Both hormones act as triggers to tell the brain when a person is full or hungry to determine when and whether to eat. Ghrelin is a hunger hormone released from the small intestine when the stomach is empty and informs the brain that it is time to eat (Carlson & Birkett, 2021). On the other hand, CCK is released to trigger digestion, slowing food movement as it leaves the stomach and tells the brain that the stomach is full and it is time to stop eating. The most notable difference between the two hormones is how they are released. Ghrelin is released in anticipation of a meal, while CCK is only released once a meal has already

6 begun. However, both hormones are essential for regulating eating, as they help inform the brain when it is time to eat or stop eating (Carlson & Birkett, 2021). Ghrelin signals to the brain that it is time for a meal, and CCK signals that it is time to stop. Without proper regulation of these hormones, eating disorders can result. 8) Describe the role of the stomach in food intake and compare its importance in producing hunger and satiety. The stomach is a sac-like organ in the digestive tract that stretches to store and breaks down ingested food and drink. It is involved in the production of appetite and feelings of satiation in response to the consumed food and drink. Its most important role is to grind food into smaller particles that can then be absorbed, and it also produces gastric juices that act as emulsifying agents, helping to mix food particles with gastric acid. The stomach is integral to creating a sense of hunger or satiety. When food is swallowed, the stomach releases hormones that regulate appetite, including ghrelin and leptin. Ghrelin is a hunger hormone, while leptin is a satiety hormone that triggers the brain to stop eating (Carlson & Birkett, 2021). When the stomach is full, it stretches and slows down the digestive process to transfer nutrients to the digestive tract. 9) Describe the role of the right hemisphere in the recognition of emotions. Identify two strategies that have been used to study this topic. The right hemisphere is believed to be primarily responsible for recognizing emotions and processing and expressing emotions. Research has shown that patients suffering from

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7 right-hemisphere brain damage are more likely to show deficits in recognition of emotions than left-hemisphere damage patients (Sheppard et al., 2020). Research has commonly used various strategies to study the right hemisphere's role in recognizing emotions. One strategy used to study this topic is the use of neurological imaging techniques such as functional magnetic resonance imaging and magnetic source imaging. These techniques measure brain activity when exposed to different types of emotion-eliciting stimuli. This has allowed researchers to gain insight into the areas of the brain that are activated during emotion recognition and the physiological pathways responsible for the recognition process. 10) Discuss the James-Lange theory of emotion and cite evidence that supports this theory. The James-Lange theory of emotion states that emotion results from physiological responses to external events. Essentially, this theory claims that when we experience a particular emotion, we first experience physiological arousal in response to an event or a stimulus. Then, once we become aware of that arousal, we attach an emotion to it. According to Stanojlović et al. (2021), when humans or animals face a potentially threatening situation, they often display physiological arousal, such as increased heart rate, sweating, and trembling, before they even have time to respond emotionally. This lends support to the idea that emotions are a result of these physiological reactions. Furthermore, studies of people with stroke-related brain damage have provided further insight into the James-Lange theory. Many people can still experience physiological

8 arousal in response to an event. Still, they cannot attach an emotion to the arousal, suggesting that the physiological arousal is connected to the emotion. References Carlson, N. R., & Birkett, M. A. (2021). Physiology of behavior. Pearson Higher Ed. Micheletti, S., Corbett, F., Atkinson, J., Braddick, O., Mattei, P., Galli, J., ... & Fazzi, E. (2021). Dorsal and ventral stream function in children with developmental coordination disorder. Frontiers in Human Neuroscience, 15, 703217. Sheppard, S. M., Keator, L. M., Breining, B. L., Wright, A. E., Saxena, S., Tippett, D. C., & Hillis, A. E. (2020). Right hemisphere ventral stream for emotional prosody identification: Evidence from acute stroke. Neurology, 94(10), e1013-e1020. Stanojlović, O., Šutulović, N., Hrnčić, D., Mladenović, D., Rašić-Marković, A., Radunović, N., & Vesković, M. (2021). Neural pathways underlying the interplay between emotional

9 experience and behavior, from old theories to modern insight. Archives of Biological Sciences, 73(3), 361-370. Zeki, S., & Leff, A. (2021). The striate cortex and hemianopia. Handbook of clinical neurology, 178, 115-129.

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