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Questions and Answers
What is the primary role of growth cones during the formation of neural circuits?
What is the primary role of growth cones during the formation of neural circuits?
What is the main purpose of circuit pruning in brain development?
What is the main purpose of circuit pruning in brain development?
What happens to the majority of extra neurons formed during brain development?
What happens to the majority of extra neurons formed during brain development?
Which of the following describes the structure that develops at the tip of a growing axon?
Which of the following describes the structure that develops at the tip of a growing axon?
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What can be argued to be a fifth stage of brain development beyond the classic four phases?
What can be argued to be a fifth stage of brain development beyond the classic four phases?
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What is the primary purpose of the body's reactions to threatening situations?
What is the primary purpose of the body's reactions to threatening situations?
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How does sweating function as a protective response?
How does sweating function as a protective response?
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Where do the fibers of the sympathetic branch originate?
Where do the fibers of the sympathetic branch originate?
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Which of the following is NOT true about the parasympathetic branch?
Which of the following is NOT true about the parasympathetic branch?
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What characterizes the relationship between the sympathetic and parasympathetic branches?
What characterizes the relationship between the sympathetic and parasympathetic branches?
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What is the first phase of the development of the nervous system?
What is the first phase of the development of the nervous system?
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What role do radial glial cells play during neural development?
What role do radial glial cells play during neural development?
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In the neural tube formation, what occurs after proliferation?
In the neural tube formation, what occurs after proliferation?
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What is the term for experiencing negative reactions when drug use is stopped?
What is the term for experiencing negative reactions when drug use is stopped?
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Which of the following opiates was initially sold as an over-the-counter analgesic?
Which of the following opiates was initially sold as an over-the-counter analgesic?
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What happens to the number of receptors during drug tolerance?
What happens to the number of receptors during drug tolerance?
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Which of the following statements about addiction is true?
Which of the following statements about addiction is true?
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What is a common physical effect of opiates?
What is a common physical effect of opiates?
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What type of drug is ethanol classified as?
What type of drug is ethanol classified as?
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What is a significant danger associated with heroin use?
What is a significant danger associated with heroin use?
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Which of the following best describes the effect of low doses of ethanol?
Which of the following best describes the effect of low doses of ethanol?
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What describes the need to continue using a drug to prevent withdrawal symptoms?
What describes the need to continue using a drug to prevent withdrawal symptoms?
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What term describes the phenomenon where increasing amounts of a drug are required to achieve the same effect?
What term describes the phenomenon where increasing amounts of a drug are required to achieve the same effect?
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What is a stated advantage of antidrug vaccines compared to traditional medication?
What is a stated advantage of antidrug vaccines compared to traditional medication?
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Which of the following best describes the concept of instinct as it relates to behavior?
Which of the following best describes the concept of instinct as it relates to behavior?
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In Drive Theory, what triggers an aroused condition called a drive?
In Drive Theory, what triggers an aroused condition called a drive?
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How does the Negative Feedback Loop function in a physiological system?
How does the Negative Feedback Loop function in a physiological system?
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What does Arousal Theory suggest about individual motivations?
What does Arousal Theory suggest about individual motivations?
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What significant aspect of motivation is emphasized in the drive theory revision?
What significant aspect of motivation is emphasized in the drive theory revision?
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According to Incentive Theory, what motivates individuals?
According to Incentive Theory, what motivates individuals?
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Which statement best describes the role of feedback in control systems?
Which statement best describes the role of feedback in control systems?
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What aspect of complex behaviors does the revised drive theory address more effectively?
What aspect of complex behaviors does the revised drive theory address more effectively?
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What is the primary neurotransmitter affected by cocaine's action as an agonist?
What is the primary neurotransmitter affected by cocaine's action as an agonist?
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Which withdrawal symptoms are commonly associated with cocaine use?
Which withdrawal symptoms are commonly associated with cocaine use?
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How does amphetamine primarily increase neurotransmitter levels in the synaptic cleft?
How does amphetamine primarily increase neurotransmitter levels in the synaptic cleft?
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What is the primary psychoactive agent found in marijuana?
What is the primary psychoactive agent found in marijuana?
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Which of the following substances acts as a direct agonist of acetylcholine?
Which of the following substances acts as a direct agonist of acetylcholine?
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What significant risk is associated with high doses of ecstasy (MDMA)?
What significant risk is associated with high doses of ecstasy (MDMA)?
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What does the Mesolimbic Pathway primarily signify in terms of brain function?
What does the Mesolimbic Pathway primarily signify in terms of brain function?
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What is a common characteristic of withdrawal symptoms from nicotine?
What is a common characteristic of withdrawal symptoms from nicotine?
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Which area of the brain is involved in detecting the rewarding properties of stimuli?
Which area of the brain is involved in detecting the rewarding properties of stimuli?
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What historical figure is known for initially promoting cocaine as a miracle drug?
What historical figure is known for initially promoting cocaine as a miracle drug?
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What type of drug is typically used in agonist treatments for addiction?
What type of drug is typically used in agonist treatments for addiction?
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What is a potential consequence of chronic use of amphetamines?
What is a potential consequence of chronic use of amphetamines?
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Which hypothesis explains that addiction may stem from a desire to avoid withdrawal symptoms?
Which hypothesis explains that addiction may stem from a desire to avoid withdrawal symptoms?
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Study Notes
The Autonomic Nervous System
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The sympathetic nervous system prepares the body for "fight or flight."
- It increases heart rate.
- It stimulates sweat glands to cool the body.
- It originates from the middle spinal cord.
- It uses a ganglion chain to connect its fibers, enabling simultaneous activation of organs.
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The parasympathetic nervous system slows the body down.
- It originates from the ends of the spinal cord.
- It doesn't have a ganglion chain, allowing for independent slowing of organs.
Brain Development
- Neurons develop in four stages.
- Proliferation: Neurons divide and multiply rapidly in the ventricular zone.
- Migration: Neurons follow radial glial cells to reach their final locations, forming the cortex.
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Circuit formation: Axons from neurons connect to their target neurons through a process called synapse formation, forming brain circuits like the corpus callosum.
- Growth cones at the ends of axons use chemical signals to find target neurons.
- Circuit pruning: Eliminates extra neurons and synapses to optimize brain function.
Addiction
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Addiction is characterized by:
- Preoccupation with obtaining a drug.
- Compulsive use of the drug despite negative consequences.
- A high tendency to relapse after quitting.
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Withdrawal is a negative reaction that occurs when drug use stops.
- It often causes symptoms opposite to the effects of the drug.
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Dependence is a state where an individual needs to keep using a drug to avoid withdrawal.
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Tolerance occurs when increasing amounts of a drug are needed to produce the same effect.
Categories of Drugs
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Opiates are derived from the opium poppy plant.
- Morphine is a powerful pain reliever.
- Heroin is a highly addictive drug that was initially marketed as a less dangerous alternative to morphine.
- Codeine is a less potent opiate used as a cough suppressant.
- Opiates bind to opiate receptors in the brain and act as direct agonists of endorphins.
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Depressants reduce the activity of the central nervous system.
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Alcohol (ethanol) has complex effects depending on dosage.
- High doses produce sedation and sleepiness.
- Low doses can have stimulating effects.
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Alcohol (ethanol) has complex effects depending on dosage.
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Stimulants increase the activity of the central nervous system.
- Cocaine produces euphoria, increases alertness, and relieves fatigue.
- Amphetamines (like methamphetamine) have similar effects to cocaine.
- Nicotine acts as an agonist of acetylcholine and dopamine, producing both stimulating and relaxing effects, depending on the duration of use.
- Caffeine blocks adenosine receptors, increasing dopamine and acetylcholine release.
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Psychedelics cause perceptual distortions.
- LSD produces sensory distortions and visual hallucinations.
- Ecstasy (MDMA) increases energy, sociability, and sexual arousal at low doses, and has similar effects to LSD at high doses.
- Angel Dust (PCP) and Ketamine produce dissociative effects and can cause schizophrenia-like symptoms.
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Marijuana contains THC, which acts as an agonist of anandamide and 2-AG.
- THC binds to cannabinoid receptors (CB1), which are widely distributed throughout the brain.
- Anandamide and 2-AG regulate the release of neurotransmitters.
Theories of Addiction
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The withdrawal avoidance hypothesis argues that addiction is driven by the desire to avoid withdrawal symptoms.
- However, this theory cannot explain why people use drugs before dependence develops, or why they relapse after withdrawal symptoms subside.
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The periventricular/periaqueductal gray area of the brain is involved in withdrawal but not pleasure.
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The ventral tegmental area (VTA) is involved in pleasure and reward.
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The mesolimbic pathway is a network including the VTA, medial forebrain bundle, and nucleus accumbens.
- It is crucial for experiencing pleasure, and drugs hijack this system to produce rewarding effects.
Neural Basis of Drug Reward
- The nucleus accumbens (NAcc) is rich in dopamine receptors.
- Nearly all abused drugs increase dopamine levels in the NAcc.
- Reducing dopamine levels in the NAcc decreases the rewarding effects of drugs.
Mesolimbic Pathway and Addiction
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The mesolimbic pathway is a general reward system.
- Electrical stimulation of the medial forebrain bundle is rewarding in rats.
- It is involved in rewarding effects of basic behaviors like eating, drinking, and sex.
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However, activity in the mesolimbic pathway cannot account for all aspects of addiction.
- People continue to use drugs even when the effects are no longer pleasurable.
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Later stages of addiction involve changes in the mesocorticolimbic dopamine system.
- The amygdala plays a role in emotional responses related to drug use.
- The hippocampus stores and retrieves drug-related memories.
Ending Dependence on Drugs
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Overcoming withdrawal symptoms is challenging, especially with nicotine and opiates.
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Fighting against relapse is essential.
Pharmacological Treatments for Dependence
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Agonist treatments replace addictive drugs with drugs that have similar effects.
- This approach helps to manage withdrawal symptoms and reduce relapse rates.
- Examples include nicotine gum and methadone for heroin addiction.
Antidrug Vaccines
- Stimulate the immune system to produce antibodies that break down the drug.
- May not be strong enough to keep patients off the drug.
- Could potentially overcome limitations of other treatments.
- Eliminates the need for patient compliance.
- Offers long-term effects.
- May avoid side effects of other medications.
- Pharmacological treatments are still somewhat controversial.
Motivation
- Involves the factors that initiate, sustain, and direct behavior.
- Provides a framework for understanding the sources of behavior.
- Recognizes the importance of unobservable variables (thoughts, feelings) in shaping behavior.
Instinct Theory
- Explains complex behaviors as innate and automatic.
- Applies to behaviors present in all members of a species.
- Examples include spider web building and bird courtship displays.
- Not very useful for explaining human behavior.
Drive Theory
- The body maintains a state of physiological balance (homeostasis).
- Departure from homeostasis creates a drive, motivating behavior to restore equilibrium.
- Applies to behaviors directly related to restoring basic tissue needs (e.g., drinking, temperature regulation).
- Less effective in explaining complex behaviors like eating or sex.
Incentive Theory
- External stimuli, such as rewards or punishments, motivate behavior.
- Examples include money, grades, or social approval.
Arousal Theory
- Individuals seek to maintain an optimal level of arousal.
- Some people prefer low arousal, while others prefer high arousal.
Revised Drive Theory
- Suggests that drive arises from states within the brain, not just the tissues.
- Offers a more complete explanation for complex behaviors.
Homeostatic Drives
- Physiological systems maintain a specific range of values (e.g., body temperature, energy reserves).
- Control systems operate on a negative feedback loop to restore balance.
- Negative feedback loops stabilize the system around a set point.
- Examples include regulating body temperature, energy levels, and fluid balance.
Positive Feedback Loops
- Amplify changes, leading to escalating effects.
- Examples include avalanches, economic collapse, and crowd behavior.
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Description
This quiz covers essential concepts related to the autonomic nervous system, including the roles of the sympathetic and parasympathetic nervous systems. It also explores the stages of brain development and the processes involved in neuron growth and migration. Test your understanding of these critical topics in neuroscience.
