Psych Test Biological Bases of Behavior

Why are psychologists concerned with

human biology?

• Psychologists working from a biological perspective study

the links between biology and behavior.

• We are biopsychosocial systems, in which biological,

psychological, and social-cultural factors interact to

influence behavior.

What are the parts of a neuron, and how are

neural impulses generated?

• Neurons are the elementary components of the nervous

system, the body’s speedy electrochemical information

system.

• A neuron receives signals through its branching dendrites,

and sends signals through its axons.

• Some axons are encased in a myelin sheath, which enables

faster transmission.

• If the combined received signals exceed a minimum

threshold, the neuron fires, transmitting an electrical

impulse (the action potential) down its axon by means of a

chemistry-to-electricity process. The neuron’s reaction is

an all-or-none process.

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Multiple-Choice Questions

How do nerve cells communicate with other

nerve cells?

• When action potentials reach the end of an axon (the axon

terminals), they stimulate the release of neurotransmitters.

• These chemical messengers carry a message from the

sending neuron across a synapse to receptor sites on a

receiving neuron.

• The sending neuron, in a process called reuptake, then

reabsorbs the excess neurotransmitter molecules in the

synaptic gap.

• If incoming signals are strong enough, the receiving

neuron generates its own action potential and relays the

message to other cells.

How do neurotransmitters influence behavior,

and how do drugs and other chemicals affect

neurotransmission?

• Neurotransmitters travel designated pathways in the brain

and may influence specific behaviors and emotions.

• Acetylcholine (ACh) affects muscle action, learning, and

memory.

• Endorphins are natural opiates released in response to pain

and exercise.

• Drugs and other chemicals affect brain chemistry at

synapses.

• Agonists excite by mimicking particular neurotransmitters

or by blocking their reuptake.

• Antagonists inhibit a particular neurotransmitter’s release

or block its effect.

What are the functions of the nervous

system’s main divisions, and what are the

three main types of neurons?

• The central nervous system (CNS)—the brain and the spinal

cord—is the nervous system’s decision maker.

• The peripheral nervous system (PNS), which connects the

CNS to the rest of the body by means of nerves, gathers

information and transmits CNS decisions to the rest of the

body.

• The two main PNS divisions are the somatic nervous

system (which enables voluntary control of the skeletal

muscles) and the autonomic nervous system (which

controls involuntary muscles and glands by means of its

sympathetic and parasympathetic divisions).

• Neurons cluster into working networks.

• There are three types of neurons:

(1) Sensory neurons carry incoming information from sense

receptors to the brain and spinal cord.

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Multiple-Choice Questions

(2) Motor neurons carry information from the brain and

spinal cord out to the muscles and glands.

(3) Interneurons communicate within the brain and spinal

cord and between sensory and motor neurons.

What is the nature and what are the

functions of the endocrine system, and how

does it interact with the nervous system?

• The endocrine system is a set of glands that secrete

hormones into the bloodstream, where they travel through

the body and affect other tissues, including the brain. The

adrenal glands, for example, release the hormones that

trigger the fight-or-flight response.

• The endocrine system’s master gland, the pituitary,

influences hormone release by other glands. In an

intricate feedback system, the brain’s hypothalamus

influences the pituitary gland, which influences other

glands, which release hormones, which in turn influence

the brain.

How do neuroscientists study the brain’s

connections to behavior and mind?

• Case studies and lesioning first revealed the general effects

of brain damage.

• Modern electrical, chemical, or magnetic stimulation has

also revealed aspects of information processing in the

brain.

• CT and MRI scans show anatomy. EEG, PET, and fMRI

(functional MRI) recordings reveal brain function.

What structures make up the brainstem,

and what are the functions of the brainstem,

thalamus, and cerebellum?

• The brainstem, the oldest part of the brain, is responsible

for automatic survival functions. Its components are

the medulla (which controls heartbeat and breathing),

the pons (which helps coordinate movements), and the

reticular formation (which affects arousal).

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Multiple-Choice Questions

• The thalamus, sitting above the brainstem, acts as the

brain’s sensory control center. The cerebellum, attached to

the rear of the brainstem, coordinates muscle movement

and balance and also helps process sensory information.

What are the limbic system’s structures and

functions?

• The limbic system is linked to emotions, memory, and

drives.

• Its neural centers include the hippocampus (which

processes conscious memories); the amygdala (involved in

responses of aggression and fear); and the hypothalamus

(involved in various bodily maintenance functions,

pleasurable rewards, and the control of the endocrine

system).

• The pituitary (the “master gland”) controls the

hypothalamus by stimulating it to trigger the release of

hormones.

What are the functions of the various

cerebral cortex regions?

• The cerebral cortex has two hemispheres, and each

hemisphere has four lobes: the frontal, parietal, occipital,

and temporal. Each lobe performs many functions and

interacts with other areas of the cortex.

• Glial cells support, nourish, and protect neurons and may

also play a role in learning and thinking.

• The motor cortex, at the rear of the frontal lobes, controls

voluntary movements.

• The somatosensory cortex, at the front of the parietal

lobes, registers and processes body touch and movement

sensations.

• Body parts requiring precise control or those that are

especially sensitive occupy the greatest amount of space in

the motor cortex and somatosensory cortex, respectively.

12-1 • Most of the brain’s cortex—the major portion of each of

the four lobes—is devoted to uncommitted association

areas, which integrate information involved in learning,

remembering, thinking, and other higher-level functions.

• Our mental experiences arise from coordinated brain

activity.

To what extent can a damaged brain

reorganize itself, and what is neurogenesis?

• If one hemisphere is damaged early in life, the other will

pick up many of its functions by reorganizing or building

new pathways. This plasticity diminishes later in life.

• The brain sometimes mends itself by forming new

neurons, a process known as neurogenesis.

What do split brains reveal about the

functions of our two brain hemispheres?

• Split-brain research (experiments on people with a

severed corpus callosum) has confirmed that in most

people, the left hemisphere is the more verbal, and that

the right hemisphere excels in visual perception and the

recognition of emotion.

• Studies of healthy people with intact brains confirm that

each hemisphere makes unique contributions to the

integrated functioning of the brain.

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Multiple-Choice Questions

What is the “dual processing” being

revealed by today’s cognitive neuroscience?

• Cognitive neuroscientists and others studying the brain

mechanisms underlying consciousness and cognition

have discovered that the mind processes information on

two separate tracks, one operating at an explicit, conscious

level and the other at an implicit, unconscious level. This

dual processing affects our perception, memory, attitudes,

and other cognitions.

biological psychology: the scientific study of the links between biological (genetic, neural, hormonal) and psychological processes. (Some biological psychologists call themselves behavioral neuroscientists, neuropsychologists, behavior geneticists, physiological psychologists, or biopsychologists.)

neuron: a nerve cell; the basic building block of the nervous system. dendrites a neuron’s bushy, branching extensions that receive messages and conduct impulses toward the cell body.

axon: the neuron extension that passes messages through its branches to other neurons or to muscles or glands.

myelin [MY-uh-lin] sheath: a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one sausage-like node to the next.

action potential: a neural impulse; a brief electrical charge that travels down an axon.

refractory: period a period of inactivity after a neuron has fired.

threshold: the level of stimulation required to trigger a neural impulse.

all-or-none response: a neuron’s reaction of either firing (with a full- strength response) or not firing.

synapse: [SIN-aps] the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft.

neurotransmitters: chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.

reuptake: a neurotransmitter’s reabsorption by the sending neuron.

antagonist: a molecule that, by binding to a receptor site, inhibits or blocks a response.

nervous system: the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.

central nervous system: (CNS) the brain and spinal cord.

peripheral nervous system: (PNS) the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.

nerves: bundled axons that form neural “cables” connecting the central nervous system with muscles, glands, and sense organs.

sensory (afferent) neurons: neurons that carry incoming information from the sensory receptors to the brain and spinal cord.

motor (efferent) neurons: neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.

interneurons: neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs.

somatic nervous system: the division of the peripheral nervous system that controls the body’s skeletal muscles. Also called the skeletal nervous system.

autonomic [aw-tuh-NAHM- ik] nervous system: (ANS) the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.

sympathetic nervous system: the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations.

parasympathetic nervous system: the division of the autonomic nervous system that calms the body, conserving its energy. reflex a simple, automatic response to a sensory stimulus, such as the knee-jerk response. endocrine [EN-duh-krin] system the body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream.

hormones: chemical messengers that are manufactured by the endocrine glands travel through the bloodstream and affect other tissues.

adrenal [ah-DREEN-el] glands: a pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress.

pituitary gland: the endocrine system’s most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

endocrine [EN-duh-krin] system: the body’s “slow” chemical communication system; a set of glands that secrete hormones into the bloodstream.

hormones: chemical messengers that are manufactured by the endocrine glands travel through the bloodstream and affect other tissues.

lesion [LEE-zhuhn]: tissue destruction. A brain lesion is a naturally or experimentally caused destruction of brain tissue.

electroencephalogram (EEG): an amplified recording of the waves of electrical activity sweeping across the brain’s surface. These waves are measured by electrodes placed on the scalp.

CT (computed tomography) scan: a series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice of the brain’s structure. (Also called CAT scan.)

PET (positron emission tomography) scan: a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task.

MRI (magnetic resonance imaging): a technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue. MRI scans show brain anatomy.

fMRI (functional MRI): a technique for revealing bloodflow and, therefore, brain activity by comparing successive MRI scans. fMRI scans show brain function as well as its structure.

brainstem: the oldest part and\ central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions.

medulla [muh-DUL-uh]: the base of the brainstem; controls heartbeat and breathing.

thalamus [THAL-uh-muss]: the brain’s sensory control center, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.

reticular formation: a nerve network that travels through the brainstem and thalamus and plays an important role in controlling arousal.

cerebellum [sehr-uh-BELL- um]: the “little brain” at the rear of the brainstem; functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory.

limbic system: neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives.

amygdala [uh-MIG-duh-la]: two lima-bean-sized neural clusters in the limbic system; linked to emotion.

hypothalamus [hi-po-THAL-uh- muss]: a neural structure lying below (hypo) the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

cerebral [seh-REE-bruhl]: cortex the intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body’s ultimate control and information-processing center.

glial cells: (glia) cells in the nervous system that support, nourish, and protect neurons; they may also play a role in learning and thinking.

frontal lobes: portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments.

parietal [puh-RYE-uh-tuhl] lobes: portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position.

occipital [ahk-SIP-uh-tuhl] lobes: portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields.

temporal lobes: portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear. motor cortex an area at the rear of the frontal lobes that controls voluntary movements.

somatosensory cortex: area at the front of the parietal lobes that registers and processes body touch and movement sensations.

association areas: areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking.

plasticity: the brain’s ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience. neurogenesis the formation of new neurons.

corpus callosum [KOR-puskah-LOW-sum]: the large band of neural fibers connecting the two brain hemispheres and carrying messages between them.

split brain: a condition resulting from surgery that isolates the brain’s two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them. consciousness our awareness of ourselves and our environment.

cognitive neuroscience: the interdisciplinary study of the brain activity linked with cognition (including perception, thinking, memory, and language).

dual processing: the principle that information is often simultaneously processed on separate conscious and unconscious tracks.

Details of the Injury

• Path of Injury: The rod passed through the frontal lobes of Gage's brain, specifically damaging areas associated with personality and executive functions.

Immediate Aftermath

Remarkably, Gage was conscious and able to walk and talk shortly after the accident. He was taken to a local doctor, Dr. John Martyn Harlow, who treated him. Gage's recovery was astonishing, but his personality underwent a significant transformation.

Changes in Personality

• After the Accident: He became impulsive, irresponsible, and exhibited erratic behavior. Friends and family noted that he was no longer the same person they had known.

Scientific Significance

Gage's case provided early evidence for the role of the frontal lobes in personality and social behavior. It challenged existing notions about the brain's structure and function, leading to advancements in the field of psychology and neuroscience.

Contributions to Neuroscience

• Localization of Function: Gage's injury highlighted the concept of localization of brain function, where specific areas of the brain are responsible for particular behaviors and cognitive processes.

• Understanding of Executive Functions: His case helped researchers understand the importance of the frontal lobes in decision-making, impulse control, and social interactions.

Critics of Evolutionary Psychology:

1. Determinism: Critics argue it oversimplifies human behavior by attributing it solely to evolutionary factors.

2. Lack of Empirical Evidence: Some claim that many hypotheses lack rigorous testing and empirical support.

3. Cultural Influence: Critics emphasize the role of culture and environment, which may be downplayed in evolutionary explanations.

4. Adaptationism: The assumption that all traits are adaptive is contested; some may be byproducts of other traits.

Rebuttals:

1. Interdisciplinary Support: Proponents argue that findings from genetics, anthropology, and psychology support evolutionary perspectives.

2. Complexity of Behavior: They assert that evolutionary psychology acknowledges the interplay of biology and environment.

3. Testable Predictions: Supporters claim that many hypotheses can be and have been tested scientifically

   Key Figures in Neuroscience and Psychology

   • Paul Broca: French physician known for Broca's area, linked to speech production.

   • Carl Wernicke: German neurologist associated with Wernicke's area, important for language comprehension.

   • Roger Sperry: American neuropsychologist known for split-brain research, studying the functions of the brain's hemispheres.

   • Michael Gazzaniga: American neuroscientist, known for his work on the cognitive neuroscience of the brain.

   • Charles Darwin: English naturalist, known for the theory of evolution and natural selection, influencing psychology and biology.

   .

   How do expressed genes affect the body?: When genes are expressed, they provide the code for creating the proteins that form our body’s building blocks.

   How do most human traits develop?: Most human traits are influenced by many genes acting together.

   What is the effect of shared family environments on personality?: Shared family environments have little effect on personality, suggesting a genetic predisposition.

   What do molecular geneticists study?: Molecular geneticists study the molecular structure and function of genes, including those that affect behavior.

   How do heritable individual differences relate to group differences?: Heritable individual differences do not necessarily imply heritable group differences.

   How do heredity and environment interact?: Our genetic predispositions and surrounding environments interact, with environments triggering gene activity.

   How do evolutionary psychologists explain behavior tendencies?: They seek to understand how traits and behavior tendencies are shaped by natural selection.

   What is a common view of sexual activity among men and women according to evolutionary psychologists?: Men tend to have a recreational view, while women tend to have a relational view of sexual activity.

   Why do men prefer multiple partners according to evolutionary psychology?: Men's attraction to multiple healthy, fertile-appearing partners increases their chances of spreading their genes.

   How do women choose mates according to evolutionary psychology?: Women search for mates with the potential for long-term investment in their offspring's survival.

   What is a key criticism of evolutionary psychology?: Critics argue that evolutionary psychologists start with an effect and work backward to an explanation.

   How do evolutionary psychologists respond to criticisms?: They argue that understanding predispositions can help overcome them and cite the value of testable predictions based on evolutionary principles.

   What does the biopsychosocial approach to individual development include?: It includes the interaction of biological, psychological, and social-cultural influences.

   What are biological influences in individual development?: Biological influences include our shared human genome