Discussion 2 psy 3200
.docx
School
South University, Savannah**We aren't endorsed by this school
Course
PSY 3300
Subject
Psychology
Date
Dec 16, 2024
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2
Uploaded by kyxh06
Discussion 2 psy 3200How Does PET Scan Work?A Positron Emission Tomography (PET) scan is a neuroimaging technique that allows scientists to measure brain activity by detecting the radioactive emissions from a tracer, typically radioactively labeled glucose. The patient is injected with glucose that has been tagged with a positron-emitting isotope. As brain cells engage in cognitive tasks, they require energy, which they obtain by consuming glucose. Areas of the brain that are more active (i.e., engaged in cognitive processing) absorb more glucose, andthe PET scanner detects the emissions to highlight active regions (Kalat, 2018).Differences Between PET, MRI, and fMRI:MRI (Magnetic Resonance Imaging) uses strong magnetic fields and radio waves to produce detailed structural images of the brain. It provides high spatial resolution but does not measure brain activity or function (Kalat, 2018). fMRI (Functional Magnetic Resonance Imaging) detects blood oxygenation changes, which indicate changes in brain activity. Unlike PET, which uses radioactive tracers to track metabolic processes, fMRI tracks the blood flow to areas of the brain as a proxy for neural activity. fMRI is particularly useful for observing the brain’s response to tasks in real-time, offering superior temporal resolution compared to PET (Kalat, 2018). PET vs. fMRI: While both methods provide functional data, PET is more focused on metabolic activity and is often used to measure the brain's glucose consumption, while fMRI reflects changes in blood flow, making it more sensitive to rapid changes in brain activity (Kalat, 2018).Why Is Radioactively Labeled Glucose Used as a Metabolic Tracer?Glucose is the primary energy source for brain cells. When the brain is more active—during cognitive tasks like thinking or processing information—it requires more glucose. By using radioactively labeled glucose, PET scans can identify the areas of the brain where glucose is being consumed more, indicating active neural regions (Kalat, 2018). If one area of the brain absorbs glucose at a higher rate than another, it suggests that this region is more engaged in the cognitive task being performed, such as visual processing or problem-solving.Neural Networks and Brain FunctioningNeural networks refer to the complex interconnected system of neurons that work together to process information. These networks can be localized or global. Localized brain functions refer to specific brain areas being specialized for distinct tasks, such as the visual cortex for vision or Broca’s area for speech production. On the other hand, global brain functioning refers to how various brain regions cooperate and communicate across different neural networks to perform more complex cognitive functions like decision-making, memory, and language processing (Kalat, 2018). Localized and Global Functioning: Neural networks represent a flexible system where both localized regions and global networks interact to process
information. For instance, when solving a math problem, the parietal lobes (involved in numerical processing) may work with prefrontal areas (involved in decision-making) and temporal lobes (involved in memory) (Kalat, 2018). These networks are dynamic and can change depending on the cognitive task being performed. Flow of Information in Neural Networks: PET and fMRI scans allow researchers to track the flow of information through these networks. PET scans highlight areas of high metabolic activity (glucose consumption), while fMRI tracks the changes in blood flow that occur with neural activation. Both scans allow us to observe how different brain regions work together in response to various cognitive tasks (Kalat, 2018).Do We Only Use a Small Percentage of Our Brain?The myth that humans only use 10% of their brain has been widely circulated, but it is incorrect. In fact, neuroimaging studies, such as PET and fMRI, have shown that virtually all parts of the brain are active at different times, even during simple tasks or while at rest (Kalat, 2018). Brain regions that may appear inactive in some contexts are still essential for maintaining basic functions like homeostasis and memory consolidation.Neural Network Activity: PET and fMRI scans demonstrate that the brain operates as an integrated network. For example, when performing a task likerecognizing a face, the fusiform gyrus (responsible for face recognition) works in tandem with areas involved in memory, attention, and emotion regulation. Even during rest or sleep, many regions of the brain are actively involved in processes like memory consolidation and emotional processing (Kalat, 2018). No "Unused" Areas: Neuroimaging data show that there are no areas of the brain that are entirely "unused" or dormant. Even seemingly inactive regions have roles in background functions or in maintaining the overall homeostasis of the body (Kalat, 2018). Therefore, the claim that 90% of the brain is unused is a myth.References:Kalat, J. W. (2018). Biological Psychology(13th ed.). Cengage Learning.