AP Psychology: Biological Bases of Behavior 2 — Questions and Answers
Question 1: Which neurotransmitter is primarily associated with pleasure, reward, and motivation?
- Dopamine (Correct answer)
- Serotonin
- GABA
- Acetylcholine
Correct answer: Dopamine
Dopamine plays a central role in the brain's reward system, motivation, and pleasure pathways.
Dopamine is a neurotransmitter crucial to the brain's reward and pleasure circuits, particularly the mesolimbic pathway. It reinforces behaviors that produce pleasure (eating, social interaction) and drives motivation and goal-directed behavior. Excessive dopamine activity is associated with schizophrenia, while deficiency causes Parkinson's disease. Addictive substances hijack dopamine pathways, creating artificially intense reward signals.
Question 2: What is the function of the hippocampus in the brain?
- Formation of new long-term memories (Correct answer)
- Regulation of fear and aggression
- Control of motor coordination
- Processing of visual information
Correct answer: Formation of new long-term memories
The hippocampus is essential for converting short-term memories into long-term memories.
The hippocampus, located in the medial temporal lobe, is critical for the formation of new declarative (explicit) memories — the consolidation of information from short-term to long-term memory. The famous case of Henry Molaison (H.M.), whose hippocampi were surgically removed to treat epilepsy, demonstrated its importance: he could not form new long-term memories but retained procedural memory, revealing different memory systems.
Question 3: What is the all-or-none principle in neural transmission?
- A neuron either fires at full strength or does not fire at all (Correct answer)
- Neurons gradually increase their firing rate
- Neural signals weaken as they travel along the axon
- Multiple neurons must fire simultaneously for a signal to transmit
Correct answer: A neuron either fires at full strength or does not fire at all
The all-or-none principle states that once the threshold of excitation is reached, a neuron fires at full intensity regardless of stimulus strength.
The all-or-none principle states that when the depolarization of a neuron's membrane reaches the threshold (approximately -55mV), an action potential fires at full strength. Stronger stimuli do not produce stronger action potentials. Instead, the brain encodes stimulus intensity through the frequency of firing (rate coding) and the number of neurons activated (population coding), not the amplitude of individual action potentials.
Question 4: Which brain structure serves as the relay station for sensory information (except smell)?
- Thalamus (Correct answer)
- Hypothalamus
- Cerebellum
- Medulla oblongata
Correct answer: Thalamus
The thalamus receives sensory input and routes it to the appropriate cortical areas for processing.
The thalamus, located deep in the center of the brain, functions as the brain's relay station. It receives sensory input from all senses except olfaction (smell, which goes directly to the olfactory cortex) and directs it to the appropriate area of the cerebral cortex. The thalamus also plays roles in consciousness, sleep-wake cycles, and attention. Damage to specific thalamic nuclei can result in loss of particular sensory functions.
Question 5: What role does the endocrine system play in behavior?
- It releases hormones that regulate mood, growth, metabolism, and stress responses (Correct answer)
- It transmits electrical impulses along nerve fibers
- It controls voluntary muscle movements
- It processes and stores memories
Correct answer: It releases hormones that regulate mood, growth, metabolism, and stress responses
The endocrine system uses hormones as chemical messengers that influence behavior, emotions, and physiological processes.
The endocrine system consists of glands (pituitary, thyroid, adrenal, etc.) that secrete hormones directly into the bloodstream. Unlike neurotransmitters, hormones act more slowly but have prolonged effects. Cortisol (stress hormone), adrenaline (fight-or-flight), testosterone and estrogen (sex hormones), and melatonin (sleep regulation) all influence behavior. The hypothalamus links the nervous and endocrine systems by controlling the pituitary gland, the 'master gland.'
Question 6: What does the split-brain research by Roger Sperry reveal about brain lateralization?
- The two hemispheres have specialized functions and can operate independently (Correct answer)
- The brain has no functional differences between hemispheres
- Only the left hemisphere processes language
- Split-brain patients lose all cognitive function
Correct answer: The two hemispheres have specialized functions and can operate independently
Sperry's research showed that the left and right hemispheres have distinct specializations and can function independently when the corpus callosum is severed.
Roger Sperry's split-brain experiments (Nobel Prize, 1981) studied patients who had undergone corpus callosotomy (severing the connection between hemispheres) to treat epilepsy. His findings revealed hemispheric specialization: the left hemisphere typically dominates language, logic, and analytical thinking, while the right hemisphere excels at spatial tasks, face recognition, and emotional processing. When disconnected, each hemisphere can independently perceive, learn, and respond.
AP Psychology: Biological Bases of Behavior 2
Which neurotransmitter is primarily associated with pleasure, reward, and motivation?