Biological Basis of Behavior Flashcards

A patient suffers a brain injury in a car accident. Following the injury, they are able to recall events from their childhood clearly but are unable to form new long-term memories of events that have occurred since the accident. This specific type of memory deficit, known as anterograde amnesia, is most likely the result of damage to which brain structure?

Answer: Hippocampus

The hippocampus, located in the medial temporal lobe, plays a crucial role in the consolidation of new information from short-term memory to long-term memory. Damage to this area severely impairs the ability to form new explicit memories, a condition known as anterograde amnesia.

The process of a neuron firing, known as an action potential, is an all-or-none electrical event. What is the critical first step that occurs when a neuron's membrane is stimulated to its threshold?

Answer: Voltage-gated sodium channels open, allowing sodium ions to rush into the cell.

When a neuron reaches its threshold of excitation, voltage-gated sodium (Na+) channels open rapidly. The influx of positively charged sodium ions causes the inside of the neuron to become positively charged relative to the outside, a process called depolarization. This is the rising phase and initial step of the action potential.

A stroke patient exhibits difficulty producing fluent, grammatical speech. They can understand language spoken to them, but their own speech is slow, halting, and consists mainly of essential nouns and verbs. This condition, known as expressive aphasia, is typically associated with damage to which specific area of the brain?

Answer: Broca's Area

Broca's Area, located in the left frontal lobe for most individuals, is critically involved in speech production. Damage to this area leads to Broca's aphasia (or expressive aphasia), characterized by the impairment of articulate, fluent speech while language comprehension remains relatively intact.

Which of the following physiological responses is mediated by the activation of the sympathetic nervous system?

Answer: Dilation of pupils

The sympathetic nervous system is responsible for the "fight-or-flight" response, preparing the body for immediate action. This includes dilating the pupils to allow more light to enter the eye, increasing heart rate, and inhibiting non-essential functions like digestion. The other options are characteristic of the parasympathetic ("rest-and-digest") system.

A college student is experiencing prolonged stress due to a heavy course load and impending final exams. Which hormone, released by the adrenal cortex, is likely to be found at elevated levels and is associated with the long-term physiological stress response?

Answer: Cortisol

Cortisol is a glucocorticoid hormone often referred to as the primary "stress hormone." While adrenaline is associated with the immediate "fight-or-flight" response, cortisol is released as part of a slower, more sustained response to chronic stress via the HPA (Hypothalamic-Pituitary-Adrenal) axis.

Which of the following neurotransmitters is most commonly associated with the regulation of mood, sleep, and appetite, with low levels being a significant factor in depressive disorders?

Answer: Serotonin

Serotonin (5-HT) is a key monoamine neurotransmitter involved in a wide range of psychological functions, including mood, sleep, and appetite regulation. Its role in mood is particularly well-known, and low levels in the brain are thought to contribute to depression. Many antidepressant medications (like SSRIs) work by increasing serotonin's availability.