Biological Basis of Behavior Flashcards
The treatment of patients with multiple neurological or psychiatric disorders is complicated by the fact that some disorders have opposing roots in the underlying brain chemistry. Administration of dopaminergic antagonists to schizophrenic patients can result in side effects resembling which of the following neurological disorders?
A. Bipolar disorder
B. Parkinson’s disease
C. Alzheimer’s disease
D. Autism spectrum disorder
B is correct. Parkinson’s disease is tied to abnormally low levels of dopamine in the substantia nigra, triggering difficulties with movement. A dopamine antagonist would reduce this region’s sensitivity to dopamine; this has been known to cause side effects when administered to some schizophrenic patients.
A, C, D: These disorders are not as directly rooted in dopaminergic activity as Parkinson’s.
A woman is hospitalized after having a stroke. An MRI scan discovers that the stroke is localized to the frontal lobe. A likely sign of such a stroke is:
A. blindness.
B. hyperimpulsivity.
C. auditory hallucinations.
D. memory deficits.
B is correct. The frontal lobe is heavily involved in executive control and decision-making; personality changes like hyperimpulsivity are a sign that this function has been compromised.
A: Blindness might be expected from a stroke in the occipital lobe, where the vision centers are located.
C: Similarly, auditory hallucinations might follow from a stroke in the hearing centers of the temporal lobe.
D: Memory deficits would likely be associated with a stroke that affects the hippocampus.
Activation of a certain neuronal receptor is found to affect Cl- ion levels and hyperpolarize the cell to -80 mV. What is the most likely identity of the neurotransmitter that activates this receptor?
A. Serotonin
B. Dopamine
C. GABA
D. Glutamate
C is correct. GABA is an inhibitory neurotransmitter that acts on Cl- ion transport. The mention of hyperpolarization should indicate that the relevant neurotransmitter has an inhibitory effect. In combination, these facts point to GABA as the most likely activator of this receptor.
Which of the following neurotransmitters is NOT a catecholamine?
A. Dopamine
B. Norepinephrine
C. Epinephrine
D. Acetylcholine
D is correct. Acetylcholine is neither a monoamine nor a catecholamine, unlike the other listed neurotransmitters.
In Huntington’s disease, cells produce a defective form of the protein huntingtin (Htt) that contains a long “tail” of glutamine residues. This tail causes aggregation of Htt into plaques, which interfere with normal neural activity and lead to cell death. However, some types of neurons (such as those in the basal ganglia) are more vulnerable to this damage than others; their deaths often trigger the first visible signs of Huntington’s disease. Based on the information given above, an early indication of this disease might be provided by:
I. working memory deficits.
II. clumsiness or lack of coordination.
III. numbness in the extremities.
A. I only
B. II only
C. III only
D. II and III only
B is correct. The basal ganglia are involved in coordinating smooth movements, and damage to this area causes the characteristic jerky movements, or chorea, associated with Huntington’s. This disease typically manifests as clumsiness or small twitches that escalate first to chorea, then to more severe writhing motions and abnormal posture.
I: Memory is affected by Huntington’s disease, but this is a later symptom. It also is not indicated by the information in the prompt, as the basal ganglia is not involved in memory.
III: Sensory issues like numbness are not characteristic of damage to the basal ganglia or any other area affected by Huntington’s disease
Cortisol, a stress hormone, plays multiple homeostatic roles relating to glucose and glycogen metabolism. In what way does cortisol likely differ from Substance H, a peptide hormone?
A. As a glucocorticoid, cortisol probably diffuses directly through plasma membranes.
B. As a mineralocorticoid, cortisol probably floats freely in the bloodstream without a carrier protein.
C. As a derivative of cholesterol, cortisol likely triggers a second messenger cascade in target cells.
D. Cortisol is a peptide, so the two hormones are probably similar.
A is correct. Cortisol is a steroid hormone (more specifically, a glucocorticoid). Due to their nonpolar structures, steroids are able to traverse cell membranes without a channel or carrier.
B: Cortisol is a glucocorticoid, not a mineralocorticoid. Even without this information, you should know that peptides (not steroids) float freely in the watery environment of the bloodstream.
C: Steroids are cholesterol derivatives, but peptides are the hormone class that are involved with second messenger systems.
D: Cortisol is not a peptide hormone.
What is the main functional difference between the adrenal medulla and the adrenal cortex?
A. The adrenal medulla is part of the sympathetic nervous system, while the adrenal cortex is part of the parasympathetic division.
B. The adrenal cortex releases compounds that also act as neurotransmitters, while the adrenal medulla releases hormones alone.
C. The adrenal medulla releases compounds that also act as neurotransmitters, while the adrenal cortex releases hormones alone.
D. The adrenal medulla is connected to the hypothalamus via a hypophyseal portal system, while the adrenal cortex is directly attached via nerve fibers.
C is correct. The adrenal medulla secretes two catecholamines, epinephrine and norepinephrine. While these molecules are technically hormones, they also act as sympathetic neurotransmitters to promote the fight-or-flight response. In contrast, the cortex releases steroid hormones, including aldosterone and cortisol.
A: The adrenal cortex has no direct relation to the parasympathetic system.
B: This is the reverse of the correct answer.
D: The description here attempts to confuse the adrenal gland with the pituitary.
An animal behaviorist learns that a gene of particular interest in a species of ape is especially prone to methylation. What is the likely consequence of this epigenetic modification?
A. That portion of DNA is subject to upregulated transcription.
B. That portion of genetic material tends to be spliced out of mRNA transcripts.
C. That portion of DNA is more heavily expressed than it would be if unmodified.
D. That portion of DNA is less heavily expressed than it would be if unmodified.
D is correct. DNA methylation is a major epigenetic change with which you should be familiar. By methylating DNA, our cells reduce the frequency of transcription of that region, thereby “silencing” it. Remember, epigenetic modifications are long-term genetic changes that are generally not passed on to the next generation.
A, C: Methylation decreases, rather than increases, transcription. Even if you did not know this, note that these two choices are essentially identical.
B: This choice relates better to introns than to methylated DNA.
A sociologist uses adoption studies to examine the prevalence of criminal behavior in young adults. She finds that children born to incarcerated offenders but raised in a different household have a higher chance of committing a felony than members of a control group. What can we conclude from this information, if the researchers find that p < 0.05?
A. Genetics certainly plays a role in the determination of future criminal behavior.
B. Genetics probably plays a role in the determination of future criminal behavior.
C. Genetics and environment appear to contribute equally to a child’s likelihood of engaging in criminal activity.
D. None of the above; the results are not statistically significant.
B is correct. A p value that is smaller than 0.05 generally denotes a statistically significant relationship. In other words, the sociologist has established an apparent link between criminally active relatives and a child’s future tendency to be a criminal himself. However, this is simply a single study and appears to be very limited; for example, it assessed only felonies, not criminal actions in general, and by definition missed individuals who were not caught. For this reason, choice B represents the least extreme conclusion.
A: This choice is too strong. While genetics is very likely to be involved somehow, we cannot conclude this from the described study alone.
Most people lack conscious memories from prior to the time when they were approximately 3.5 years old. Which term is given to this phenomenon?
A. The Moro reflex
B. Baby dementia
C. The recency effect
D. Infantile amnesia
D is correct. Although babies can learn and use their memories, most or all of these memories are not retained into adulthood. The average adult can recollect events from around age 3-4, but not earlier. This phenomenon is known as infantile amnesia.
A: The Moro reflex is an instinctual response to the feeling of falling. An infant will throw his head back, extend his arms, and cry when physical support is withdrawn.
B: This term, though creative, is not a scientific concept.
C: The recency effect refers to our tendency to remember the first term in a list more readily than terms given in the middle. It has no relation to infantile amnesia.
Which of the following theories of personality places a high value on self-actualization?
A. Psychoanalytic theory
B. Biological theory
C. Humanistic theory
D. Trait theory
C is correct. The humanistic approach to personality posits that individuals naturally strive for self-actualization, or the fulfillment of one’s potential. This goal actually forms the top of Maslow’s hierarchy of needs; in other words, humans have a psychological need for self-actualization and can work to achieve it once more basic needs have been met.
A: Psychoanalytic theory, largely developed by Sigmund Freud, focuses more on unconscious urges than on the fulfillment of potential. This theory includes the division of the personality into the id, ego, and superego.
B: Biological theories typically posit that personality is genetic in nature.
D: Trait theories aim to divide personality into a number of traits, or personal qualities, that may or may not be expressed by particular individuals.
Freud’s psychoanalytic theory separates human personality into three main “structures,” or components. Which of these choices accurately describes one of these components?
A. The superego drives the individual to accomplish moral aims, and in doing so, often counteracts the id.
B. The id balances input from the ego and the superego and tends to dominate in day-to-day adult life.
C. The ego is more unconscious in nature than either the id or the superego.
D. The ego represents the most base, aggressive, and pleasure-seeking aspect of personality.
A is correct. The superego is the “moral” component of human personality. It typically drives individuals to avoid behaviors that are morally wrong while striving to fulfill realistic goals.
B: While the id (the pleasure-driven, simplistic portion of personality) does dominate behavior in very young children, the ego takes over in late childhood and adulthood.
C: The ego is largely conscious, as it must balance input from the superego and the ego to guide the person’s day-to-day actions. It is the id and the superego that are more unconscious in nature.
D: This choice describes the id, not the ego.
Which of the following is NOT one of Goldberg’s five factors or scales along which personality can vary?
A. Conformity
B. Neuroticism
C. Openness to experience
D. Conscientiousness
A is correct. Goldberg’s five dimensions are agreeableness (the degree to which one values getting along with others), extraversion (the degree to which one engages with people and the external world) conscientiousness (a person’s level of self-discipline and focus on achievement) neuroticism (the degree to which one experiences negative emotions like anxiety, depression, or anger) and openness to experience (the amount of value placed on novelty, creativity, and variety of experiences). Conformity is not a factor on this list.
An individual has a history of superficial friendships based on who he finds worthy of his attention. His romantic partners complain that he cares more about how they fit into his idealized version of a perfect couple, rather than focusing on their wants and needs. He is extremely sensitive to jokes at his expense and spends a great deal of time ruminating about perceived slights to his character or competence. Based on this description, this individual most likely has:
A. paranoid personality disorder.
B. narcissistic personality disorder.
C. borderline personality disorder.
D. dependent personality disorder.
B is correct. Some classic signs of narcissistic personality disorder include an excessive concentration on one’s own self-image, a heightened valuation of external sources of self-esteem, behavior focused on maintaining self-esteem to the exclusion of genuine interest in others’ needs, wants, or experiences, and feelings of entitlement. This individual displays all of these signs.
A, C, D: The person described lacks signs like a generalized mistrust toward others (A), emotional instability or black/white thinking (C), and dependence on others to make one’s life decisions or excessive subordination (D).
Brain scans have been used to determine the patterns of brain activation associated with certain personality disorders. A group of subjects is exposed to videos of people being killed in accidents while their brain activation is monitored with an fMRI apparatus. What pattern of activation might be expected from people with antisocial personality disorder?
A. Overactivation of areas associated with higher reasoning
B. Underactivation of areas associated with perceptual processing
C. Overactivation of areas associated with memory formation
D. Underactivation of areas associated with emotional processing
D is correct. Individuals with antisocial personality disorder, also known as sociopaths, tend to display a remarkable lack of emotional affect when exposed to stimuli that would distress most people. This lack of affect is particularly pronounced in situations that normally provoke empathetic responses, like watching videos of people dying. Therefore, underactivation of areas associated with emotional processing, like the amygdala, would be expected in this case. Sociopaths actually tend to have smaller amygdalas than average.