MCAT Behavioral Sciences Review - Kaplan Test Prep 2021–2022

Conclusion
A Brief History of Neuropsychology

Behavioral psychology is the study of all physical and mental actions based on the response of the body to external stimuli, specifically the activity of the nervous and endocrine systems. The nervous system is a complex organization of structures and neurons that communicate and coordinate information. The endocrine system, in conjunction with the nervous system, controls human behavior. Aside from neurotransmitter and hormonal control of behavior, certain behaviors are genetically passed from generation to generation, as are many other physical traits. The genetic aspects of behavior are thought to interact with the learned components of behavior. Human behavior is also studied as it correlates to the development from embryo to fetus to infant and well into adolescence and adulthood. The development of motor skills and social behavior is seen to progress at a consistent rate across the species.

In the next chapter, our focus will be on the neurological systems used to interact with the world—most notably, those systems that exist for sensation and perception of the environment. These include vision, hearing, smell and taste, somatosensation, and others.

Concept Summary

A Brief History of Neuropsychology

· Neuropsychology is the study of the connection between the nervous system and behavior. It most often focuses on the functions of various brain regions.

Organization of the Human Nervous System

· There are three types of neurons in the nervous system: sensory (afferent) neurons, motor (efferent) neurons, and interneurons.

· Reflex arcs use the ability of interneurons in the spinal cord to relay information to the source of stimuli while simultaneously routing it to the brain.

· The nervous system is made up of the central nervous system (CNS; brain and spinal cord) and peripheral nervous system (PNS; most cranial and spinal nerves).

o The PNS is divided into the somatic (voluntary) and autonomic (automatic) divisions.

o The autonomic system is further divided into the parasympathetic (rest-and-digest) and sympathetic (fight-or-flight) branches.

Organization of the Brain

· The brain has three subdivisions: hindbrain, midbrain, and forebrain.

o The hindbrain contains the cerebellum, medulla oblongata, and reticular formation.

o The midbrain contains the inferior and superior colliculi.

o The forebrain contains the thalamus, hypothalamus, basal ganglia, limbic system, and cerebral cortex.

· Methods of studying the brain include studying humans and animals with lesions, electrical stimulation and activity recording (including electroencephalography [EEG]), and regional cerebral blood flow.

Parts of the Forebrain

· The thalamus is a relay station for sensory information.

· The hypothalamus maintains homeostasis and integrates with the endocrine system through the hypophyseal portal system that connects it to the anterior pituitary.

· The basal ganglia smoothen movements and help maintain postural stability.

· The limbic system, which contains the septal nuclei, amygdala, and hippocampus, controls emotion and memory.

o The septal nuclei are involved with feelings of pleasure, pleasure-seeking behavior, and addiction.

o The amygdala controls fear and aggression.

o The hippocampus consolidates memories and communicates with other parts of the limbic system through an extension called the fornix.

· The cerebral cortex is divided into four lobes: frontal, parietal, occipital, and temporal.

o The frontal lobe controls executive function, impulse control, long-term planning, motor function, and speech production.

o The parietal lobe controls sensations of touch, pressure, temperature, and pain; spatial processing; orientation; and manipulation.

o The occipital lobe controls visual processing.

o The temporal lobe controls sound processing, speech perception, memory, and emotion.

· The brain is divided into two cerebral hemispheres, left and right. In most individuals, the left hemisphere is the dominant hemisphere for language.

Influences on Behavior

· Neurotransmitters are released by neurons and carry a signal to another neuron or effector (a muscle fiber or a gland).

o Acetylcholine is used by the somatic nervous system (to move muscles), the parasympathetic nervous system, and the central nervous system (for alertness).

o Dopamine maintains smooth movements and steady posture.

o Endorphins and enkephalins act as natural painkillers.

o Epinephrine and norepinephrine maintain wakefulness and alertness and mediate fight-or-flight responses. Epinephrine tends to act as a hormone, and norepinephrine tends to act more classically as a neurotransmitter.

o γ-Aminobutyric acid (GABA) and glycine act as brain “stabilizers.”

o Glutamate acts as an excitatory neurotransmitter in the brain.

o Serotonin modulates mood, sleep patterns, eating patterns, and dreaming.

· The endocrine system is tied to the nervous system through the hypothalamus and the anterior pituitary, as well as a few other hormones.

o Cortisol is a stress hormone released by the adrenal cortex.

o Testosterone and estrogen mediate libido; testosterone also increases aggressive behavior. Both are released by the adrenal cortex. In males, the testes also produce testosterone. In females, the ovaries also produce estrogen.

o Epinephrine and norepinephrine are released by the adrenal medulla and cause physiological changes associated with the sympathetic nervous system.

· Nature vs. nurture is a classic debate regarding the relative contributions of genetics (nature) and environment (nurture) to an individual’s traits. For most traits, both nature and nurture play a role. The relative effects of each can be studied.

o Family studies look at the relative frequency of a trait within a family compared to the general population.

o Twin studies compare concordance rates between monozygotic (identical) and dizygotic (fraternal) twins.

o Adoption studies compare similarities between adopted children and their adoptive parents, relative to similarities with their biological parents.

Development

· The nervous system develops through neurulation, in which the notochord stimulates overlying ectoderm to fold over, creating a neural tube topped with neural crest cells.

o The neural tube becomes the central nervous system (CNS).

o The neural crest cells spread out throughout the body, differentiating into many different tissues.

· Primitive reflexes exist in infants and should disappear with age. Most primitive reflexes serve (or served, in earlier times) a protective role. They can reappear in certain nervous system disorders.

o In the rooting reflex, the infant turns his or her head toward anything that brushes the cheek.

o In the Moro reflex, the infant extends the arms, then slowly retracts them and cries in response to a sensation of falling.

o In the Babinski reflex, the big toe is extended and the other toes fan in response to the brushing of the sole of the foot.

o In the grasping reflex, the infant grabs anything put into his or her hand.

· Developmental milestones give an indication of what skills and abilities a child should have at a given age. Most children adhere closely to these milestones, deviating by only one or two months.

o Gross and fine motor abilities progress head to toe and core to periphery.

o Social skills shift from parent-oriented to self-oriented to other-oriented.

o Language skills become increasingly complex.

Answers to Concept Checks

· 1.1

1.

§ Franz Gall: phrenology; associated development of a trait with growth of its relevant part of the brain.

§ Pierre Flourens: extirpation/ablation; concluded that different brain regions have specific functions.

§ William James: “father of American psychology”; pushed for importance of studying adaptations of the individual to his or her environment.

§ John Dewey: credited with the landmark article on functionalism; argued for studying the entire organism as a whole.

§ Paul Broca: correlated pathology with specific brain regions, such as speech production from Broca’s area.

§ Hermann von Helmholtz: measured speed of a nerve impulse.

§ Sir Charles Sherrington: inferred the existence of synapses.

· 1.2

1. The central nervous system includes the brain and spinal cord. The peripheral nervous system includes most of the cranial and spinal nerves and sensors.

2. Afferent (sensory) neurons bring signals from a sensor to the central nervous system. Efferent (motor) neurons bring signals from the central nervous system to an effector.

3. The somatic nervous system is responsible for voluntary actions; most notably, moving muscles. The autonomic nervous system is responsible for involuntary actions, like heart rate, bronchial dilation, dilation of the eyes, exocrine gland function, and peristalsis.

4. The sympathetic nervous system promotes a fight-or-flight response, with increased heart rate and bronchial dilation, redistribution of blood to locomotor muscles, dilation of the eyes, and slowing of digestive and urinary functions. The parasympathetic nervous system promotes rest-and-digest functions, slowing heart rate and constricting the bronchi, redistributing blood to the gut, promoting exocrine secretions, constricting the pupils, and promoting peristalsis and urinary function.

· 1.3

1.

2. Methods used for mapping the brain include studying humans with brain lesions, extirpation, stimulation or recording with electrodes (cortical mapping, single-cell electrode recordings, electroencephalogram [EEG]), and regional cerebral blood flow (rCBF).

3. From most deep to most superficial, the structures surrounding the brain are the meninges, bone, periosteum, and skin.

· 1.4

1. 1—A, 2—H, 3—F, 4—E, 5—C, 6—I, 7—G, 8—D, 9—B

2.

3.

4. Ipsilateral communication occurs when cerebral hemispheres communicate with the same side of the body. Contralateral communication occurs when cerebral hemispheres communicate with the opposite side of the body.

5. The dominant hemisphere is typically defined as the one that is more heavily stimulated during language reception and production.

· 1.5

1. 1—F, 2—E, 3—D, 4—A, 5—B, 6—G, 7—C

2. The hypothalamus controls release of pituitary hormones; the pituitary is the “master gland” that triggers hormone secretion in many other endocrine glands. The adrenal medulla produces adrenaline (epinephrine), which causes sympathetic nervous system effects throughout the body. The adrenal cortex produces cortisol, a stress hormone. The adrenal cortex and testes produce testosterone, which is associated with libido.

3. Nature is defined as heredity, or the influence of inherited characteristics on behavior. Nurture refers to the influence of environment and physical surroundings on behavior. It has long been debated whether nature or nurture has the larger influence; it is a complicated situation, but for most traits, both exert some influence.

4.

· 1.6

1. Neurulation occurs when a furrow is produced from ectoderm overlying the notochord and consists of the neural groove and two neural folds. As the neural folds grow, the cells at their leading edge are called neural crest cells. When the neural folds fuse, this creates the neural tube, which will form the CNS.

2.

3. Gross motor development proceeds from head to toe, and from the core to the periphery.

Shared Concepts

· Behavioral Sciences Chapter 2

o Sensation and Perception

· Behavioral Sciences Chapter 3

o Learning and Memory

· Behavioral Sciences Chapter 4

o Cognition, Consciousness, and Language

· Biology Review Chapter 3

o Embryogenesis and Development

· Biology Review Chapter 4

o The Nervous System

· Biology Review Chapter 5

o The Endocrine System

Discrete Practice Questions

1. Which of the following is true regarding nerve cells?

1. Sensory neurons are also referred to as efferent neurons.

2. Interneurons are also referred to as afferent neurons.

3. Motor neurons transmit information from receptors to the brain.

4. Sensory neurons transmit information from receptors to the brain.

2. Which component of the nervous system is NOT involved in the initial reflexive response to pain?

1. Spinal cord

2. Cerebral cortex

3. Interneuron

4. Motor neuron

3. A child has experienced nervous system damage and can no longer coordinate the movements to dribble a basketball, although she can still walk in an uncoordinated fashion. Which region of the central nervous system was most likely affected?

1. Forebrain

2. Midbrain

3. Hindbrain

4. Spinal cord

4. The temporal lobe deals with all of the following EXCEPT:

1. language comprehension.

2. memory.

3. emotion.

4. motor skills.

5. Which part of the brain deals with both homeostasis and emotions?

1. Cerebellum

2. Pons

3. Hypothalamus

4. Thalamus

6. Which of the following activities would most likely be completed by the right hemisphere of a left-handed person?

1. Finding a car in a parking lot

2. Learning a new language

3. Reading a book for pleasure

4. Jumping rope with friends

7. Which of the following is/are true with regard to neurulation?

1. The neural tube differentiates from endoderm.

2. The neural tube becomes the peripheral nervous system.

3. Neural crest cells migrate from their original site.

4. I only

5. III only

6. II and III only

7. I, II, and III

8. Which of the following neurotransmitters is NOT classified as a catecholamine?

1. Epinephrine

2. Norepinephrine

3. Dopamine

4. Acetylcholine

9. If the amount of acetylcholinesterase, an enzyme that breaks down acetylcholine, is increased, which of the following would likely be the result?

1. Weakness of muscle movements

2. Excessive pain or discomfort

3. Mood swings and mood instability

4. Auditory and visual hallucinations

10. The adrenal glands do all of the following EXCEPT:

1. promote the fight-or-flight response via estrogen.

2. produce stress responses via cortisol.

3. produce both hormones and neurotransmitters.

4. release estrogen in males and testosterone in females.

11. A disorder of the pineal gland would most likely result in which of the following disorders?

1. High blood pressure

2. Diabetes

3. Insomnia

4. Hyperthyroidism

12. Which of the following neurotransmitters is associated with both schizophrenia and Parkinson’s disease?

1. GABA

2. Serotonin

3. Dopamine

4. Enkephalins

13. In a personality survey, which set of twins would be expected to score most similarly?

1. Identical twins raised in different homes

2. Fraternal twins raised in different homes

3. Identical twins raised in the same home

4. Fraternal twins raised in the same home

14. During a physical examination, a physician brushes the bottom of the foot of a fifty-year-old patient with multiple sclerosis. Her toes are observed to curl toward the bottom of her foot, with no fanning of the toes. This response is:

1. abnormal, and evidence that she is exhibiting a primitive reflex.

2. normal, and evidence that she is exhibiting a primitive reflex.

3. abnormal, and evidence that she is not exhibiting a primitive reflex.

4. normal, and evidence that she is not exhibiting a primitive reflex.

15. Which of the following fine motor tasks would one expect to see first in an infant?

1. Grasping for objects with two fingers

2. Following objects with the eyes

3. Scribbling with a crayon

4. Moving a toy from one hand to the other

Discrete Practice Answers

1. DSensory neurons are also referred to as afferent neurons, while motor neurons are also referred to as efferent neurons, eliminating (A) and (B). Motor neurons transmit motor information from the brain to the body, contrary to (C), and sensory neurons transmit sensory information from receptors to the brain.

2. BThe cerebral cortex is not involved in the initial reflexive response to pain. Instead, the sensory receptors send information to the interneurons in the spinal cord, which stimulate a motor neuron to allow quick withdrawal. While the brain does ultimately get the signal, the reflexive withdrawal has already occurred by that time.

3. CThe hindbrain is responsible for balance and motor coordination, which would be necessary for dribbling a basketball. The midbrain, (B), manages sensorimotor reflexes that also promote survival. The forebrain, (A), is associated with emotion, memory, and higher-order cognition. The spinal cord, (D), is likely not damaged as the child can still walk.

4. DThe temporal lobes have many functions, but motor skills are not associated with this area. The temporal lobes contain Wernicke’s area, which is responsible for language comprehension, (A). The temporal lobes also function in memory and emotion, (B) and (C), because they contain the hippocampus and amygdala. Motor skills are associated with the frontal lobe (primary motor cortex), basal ganglia (smooth movements), and cerebellum (coordination).

5. CThe hypothalamus is responsible for homeostatic and emotional functions. The cerebellum, (A), is responsible for maintaining posture and balance while the pons, (B), is above the medulla and contains sensory and motor tracts between the cortex and the medulla. The thalamus, (D), acts as a relay station for sensory information.

6. AThe right hemisphere is usually the nondominant hemisphere, even in left-handed individuals. Sense of direction is an ability of the nondominant hemisphere. The other answer choices are all abilities attributed to the dominant hemisphere.

7. BNeurulation occurs when the notochord causes differentiation of overlying ectoderm into the neural tube and neural crest cells. The neural tube ultimately becomes the central nervous system (brain and spinal cord), and neural crest cells migrate to other sites in the body to differentiate into a number of different tissues. Thus, only statement III is true.

8. DCatecholamines are the hormones produced by the adrenal glands during the fight-or-flight response, and include epinephrine, norepinephrine, and dopamine. Acetylcholine is produced by cholinergic neurons and is, thus, not a catecholamine.

9. AIf there were increased amounts of acetylcholinesterase, more acetylcholine would be degraded, lowering acetylcholine levels in the body. Low levels of acetylcholine would result in weakness or paralysis of muscles. Pain, (B), could result if one were injured and endorphins were found in low levels. Mood swings, (C), could be a result of varying levels of serotonin. Hallucinations, (D), have been seen to result from high levels of dopamine.

10. AThe adrenal glands do promote the fight-or-flight response, but through epinephrine and norepinephrine, not estrogen. The adrenal cortex produces both estrogen and testosterone in both sexes, as mentioned in (D), thus serving as a source of estrogen in males and testosterone in females.

11. CThe pineal gland is responsible for producing melatonin, which controls the body’s circadian rhythm. Insomnia would be a disturbance of this circadian rhythm, and may be attributable to a pineal gland disorder in some cases. Hypertension, diabetes, and hyperthyroidism would be unrelated to issues with the pineal gland.

12. CSchizophrenia is associated with high levels of dopamine or high sensitivity to dopamine. Parkinson’s disease is associated with destruction of the dopaminergic neurons in the basal ganglia.

13. CPersonality is seen to be somewhat hereditary, as monozygotic, or identical, twins have been seen to express more of the same personality traits. However, environment is also a factor. Thus, identical twins raised in the same home would be expected to have the most similar personalities.

14. DThe Babinski reflex is a primitive reflex that refers to an extension of the big toe accompanied by fanning of the other toes. It is normal in infants, but should disappear with time—certainly by the time a child begins to walk. In a fifty-year-old woman, the Babinski reflex would be abnormal. However, despite her neurological illness, this patient is exhibiting a normal response to the brushing of her foot; that is, she is not showing the Babinski reflex.

15. BMotor skills tend to develop from the core toward the periphery. Following objects with the eyes occurs around four weeks of age. The other actions all require movements of the hand, which do not occur in an organized fashion until later.

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