Psych 101 – Chapter 2: Biological Psychology

Studying bumps on the skull
Localization of Function
The idea that various brain regions have particular functions
Biological Perspective
Concerned with the links between biology & behavior
What do phrenology & psychology’s biological perspective have in common?
They share a focus on the links between biology & behavior. Phrenology faded because it had no scientific basis – skull bumps don’t reveal mental traits & abilities.
A nerve cell; The basic building block of the NS; Each consists of a cell body & its branching fibers; Generates electricity from chemical events
Cell Body
The cell’s life support center
A neuron’s bushy, branching extensions that receive messages & conduct impulses toward the cell body
The neuron extension that passes messages through its branches to other neurons or to muscles or glands; Long distances
Myelin Sheath
A fatty tissue layer encasing the axons of some neurons; Speeds their impulses; Insulation
Multiple Sclerosis
Occurs if the myelin sheath degenerates, causing slower communication to muscles & eventual loss of muscle control
Action Potential
A neural impulse; A brief electrical charge that travels down an axon
Resting Potential
The fluid outside an axon’s membrane has mostly positively charged ions, while its interior has mostly negatively charged ions
Selectively Permeable
The axon’s surface is very selective about what it allows through its gates
Refractory Period
Resting pause; The neuron pumps Na+ back outside (NA+/K+ Pump)
Pushing a neuron’s accelerator; Action potential will travel down the axon, branching into junctions; Increased stimulation will not increase the neural impulse’s intensity (only will cause more neurons to fire more frequently)
Pushing a neuron’s brake
The level of stimulation required to trigger a neural impulse; All-or-none response
Action Potential Process
1) Neuron stimulation causes a brief change in electrical charge. If strong enough, this produces depolarization & an action potential
2) This depolarization produces another action potential a little farther along the axon. Gates in this neighboring area now open, & charged sodium atoms rush in. A pump in the cell membrane (the sodium/potassium pump) transports the sodium ions back out of the cell
3) As the action potential continues speedily down the axon, the first section has now completely recharged
When a neuron fires an action potential, the information travels through the axon, the dendrites, and the axon’s terminal branches, but not in that order. Place these 3 structures in the correct order.
Dendrites, axon, axon’s terminal branches
How does our NS allow us to experience the difference between a slap and a tap on the back?
Stronger stimuli (the slap) cause more neurons to fire and to fire more frequently than happens with weaker stimuli (the tap)
The junction between the axon tip of the sending neuron & the dendrite or cell body of the receiving neuron
Synaptic Gap / Synaptic Cleft
The tiny gap at the junction
Chemical messengers that diffuse across a synapse & excite or inhibit an adjacent neuron
The sending neuron reabsorbs the excess neurotransmitters
Neuron Communication Process
1) Electrical impulses (action potentials) travel down a neuron’s axon until reaching a tiny junction known as a synapse
2) When an action potential reaches an axon terminal, it stimulates the release of neurotransmitter molecules. These molecules cross the synaptic gap & bind to receptor sites on the receiving neuron. This allows electrically charged atoms to enter the receiving neuron & excite or inhibit a new action potential
3) The sending neuron normally reabsorbs excess neurotransmitter molecules, a process called reuptake
What happens in the synaptic gap? What is reuptake?
Neurons send neurotransmitters (chemical messengers) to 1 another across this tiny space between 1 neuron’s terminal branch and the next neuron’s dendrite. In reuptake, a sending neuron reabsorbs the extra neurotransmitters
Acetylcholine (ACh)
One of the most common neurotransmitters; At every junction between motor neuron & skeletal muscle; When released, muscle contracts; When blocked, muscles can’t contract – Botox: ACh antagonist; Enables muscle action, learning, & memory; Too little causes Alzheimer’s disease
Neurotransmitter that can either excite or inhibit; Influences mood, control of voluntary experiences & processing of rewarding experiences; Too much causes schizophrenia; Too little causes Parkinson’s (tremors)
Neurotransmitter that affects mood, hunger, sleep, pain, & arousal; Targeted by many anti-depressants (SSRIs)
Neurotransmitter that helps control alertness & arousal; Too little causes depression
GABA (gamma-aminobutyric acid)
Neurotransmitter that is a major inhibitory neurotransmitter; Prevents neurons from generating action potential; When it binds, there’s an influx of Cl- into the cell; Facilitates sleep & reduces arousal of NS; E.g. Xanax: GABA agonist; Too little causes seizures, tremors, & insomnia
Neurotransmitter that is a major excitatory neurotransmitter; Involved in memory; Too much overstimulates the brain, producing migraines or seizures (which is why some people avoid MSG, monosodium glutamate, in food)
“Morphine within”; Natural, opiatelike neurotransmitters linked to reduce pain & give pleasure
Bind to receptors & mimic neurotransmitter effects
Bind to receptors to block a neurotransmitter’s functioning
Nervous System
The body’s speedy, electrochemical communication network, consisting of all the nerve cells of the PNS & CNS
Central Nervous System (CNS)
The brain & spinal cord; The body’s decision maker
Peripheral Nervous System (PNS)
The sensory & motor neurons that connect the CNS to the rest of the body; Somatic Nervous System & Autonomic Nervous System
Bundled axons that form neural “cables” connecting the CNS with muscles, glands, & sense organs
Sensory Neurons
Neurons that carry incoming info from the sensory receptors to the brain & spinal cord
Motor Neurons
Neurons that carry outgoing info from the brain & spinal cord to the muscles & glands
Neurons that internally communicate between sensory inputs & motor outputs
Somatic Nervous System (Skeletal NS)
Part of PNS; Controls the body’s skeletal muscles
Autonomic Nervous System (ANS)
Part of PNS; Controls the glands & muscles of the internal organs (heart); Sympathetic NS & Parasympathetic NS
Sympathetic Nervous System
Part of ANS; Active during fight or flight responses; Arouses the body, mobilizing its energy in stressful situations
Parasympathetic Nervous System
Part of ANS; Active during rest & digestion; Calms the body, conserving its energy
What bodily changes does your ANS direct before and after you give an important speech?
Your ANS’s sympathetic division will arouse you. It accelerates your heartbeat, raises your blood pressure and blood sugar, slows your digestion, and cools you with perspiration. After the speech, your ANS’s parasympathetic division will reverse these effects.
Neural Networks
The work groups that the brain’s neurons cluster into
Interprets & stores info & communicates with muscles, glands, & organs
Spinal Cord
A 2-way info highway connecting between the PNS & the brain; Reflexes
A simple, automatic response to a sensory stimulus, such as the knee-jerk response; Interneuron – allows the sensory neuron to communicate directly with a motor neuron in reaction to painful stimuli
Endocrine System
The body’s “slow” communication system; A set of glands that secrete hormones into the bloodstream
Chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, & affect other tissues
Adrenal Glands
A pair of endocrine glands that sit just above the kidneys & secrete hormones (epinephrine & norepinephrine) that help arouse the body in times of stress; “Fight-or-flight” response
Pituitary gland
The endocrine system’s most influential gland; Under the influence of the hypothalamus, it regulates growth & controls other endocrine glands
Thyroid Gland
Affects metabolism
Help regulate the level of calcium in the blood
Regulates the level of sugar in the blood
Secretes male sex hormones
Secretes female sex hormones
Feedback System
Info goes from brain to pituitary to other glands to hormones to body & brain
Why is the pituitary gland called the “master gland”?
Responding to signals from the hypothalamus, the pituitary releases hormones that trigger other endocrine glands to secrete hormones that in turn influence brain and behavior.
How are the nervous and endocrine systems alike, and how do they differ?
Both of these communication systems produce chemical molecules that act on the body’s receptors to influence our behavior and emotions. The endocrine system, which secretes hormones into the bloodstream, delivers its messages much more slowly than the speedy nervous system, and the effects of the endocrine system’s messages tend to linger much longer than those of the NS
Tissue destruction; A naturally or experimentally caused destruction of brain tissue
Electroencephalogram (EEG)
An amplified recording of the waves of electrical activity that sweep across the brain’s surface; These waves are measured by electrodes placed on the scalp
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)
Uses magnetic fields & radio waves to produce computer-generated images of soft tissue; Shows brain anatomy
fMRI (functional MRI)
Reveals bloodflow &, therefore, brain activity by comparing successive MRI scans; Shows brain function
Medulla, Pons, Cerebellum; Basic functions that sustain the body
The brain’s oldest & innermost region; It begins where the spinal cord swells as it enters the skull; Responsible for automatic survival functions; Medulla & Pons
The base of the brainstem; Controls heartbeat & breathing
Just above the medulla; Coordinates movements
The “little brain” at the rear of the brainstem; Functions include processing sensory input & coordinating movement output/balance & timing
Controls basic sensory responses & those that are involved in the control of voluntary movement; Includes neurons that contain dense DA receptors & activity that send messages to higher brain centers that control movement
Part of Midbrain; Coordinates the sensation of motion with actions
Most visibly obvious region of the brain; Multiple interconnections & structures for complex processes like emotion, memory, thinking & reasoning; Basal Ganglia, Limbic System
Basal Ganglia
Planned voluntary movement & reward processing; Nucleus Accumbens
Nucleus Accumbens
Basal Ganglia; Experiencing pleasure & reward
Limbic System
Neural system located below the cerebral hemispheres; Associated with emotions & memory; Amygdala, Hippocampus; Thalamus, Hypothalamus
Limbic System; 2 lima-bean-sized neural clusters; Memory & fear emotion
Limbic System; Greek for seahorse; Forming new memories
The brain’s sensory switchboard, located on top of the brainstem; It directs messages to the sensory receiving areas in the cortex & transmits replies to the cerebellum & medulla
Limbic System; Below the thalamus; Thermostat directing several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, & is linked to emotion & reward
Reticular (“Netlike”) Formation
A nerve network that travels through the brainstem & plays an important role in controlling arousal
In what brain region would damage most likely to (1) disrupt your ability to skip rope? (2) disrupt your ability to hear and taste? (3) perhaps leave you in a coma? (4) cut off the very breath and heartbeat of life?
1) Cerebellum
2) Thalamus
3) Reticular formation
4) Medulla
Cerebral Hemispheres
The 2 halves of the brain
Electrical stimulation of a cat’s amygdala provokes angry reactions, suggesting the amygdala’s role in aggression. Which ANS division is activated by such stimulation?
The sympathetic nervous system.
Cerebral Cortex
The intricate fabric of interconnected neural cells covering the cerebral hemispheres; The body’s ultimate control & information-processing center; 4 lobes
Glial Cells (Glia)
“Glue cells”; Cells in the NS that support, nourish, & protect neurons; Also play a role in learning & thinking
Frontal Lobes
Behind the forehead; Involved in speaking & muscle movements & in making plans & judgements; Primary Motor Cortex; Broca’s Area
Parietal Lobes
At the top of the head & toward the ear; Receives sensory input for touch & body position; Mathematical & visual-spatial tasks; Somato-sensory Area
Occipital Lobes
Back of the head; Includes areas that receive info from the visual fields
Temporal Lobes
Above the ears; Hearing, language, & object recognition; Wernicke’s Area
Motor Cortex
An area at the rear of the frontal lobes that controls voluntary movements
Sensory Cortex
Area at the front of parietal lobes that registers & processes body touch & movement sensations
Association Areas
Areas of the cerebral cortex that are not involved in primary motor or sensory functions; Involved in higher mental functions such as learning, remembering, thinking, & speaking
The brain’s ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience
The formation of new neurons
Corpus Callosum
The large band of neural fibers connecting the 2 brain hemispheres & carrying messages between them
Split Brain
A condition resulting from surgery that isolates the brain’s 2 hemispheres by cutting the fibers connecting them
Left Hemisphere of Brain
Specializes in language & math; Processes info in analytical, piecemeal style; Speech generation – Broca’s Area
Right Hemisphere of Brain
Specializes in visual-spatial skills, recogonition of visual stimuli, musical processing; Process info in more global, holistic style; Understands language but doesn’t play role in speaking
Biological Psychology
The study of the brain, the NS, genetics, & how they relate to behavior & mental processes
Broca’s Area
Left frontal lobe, Speech generation; Damage – difficulty speaking & making grammar errors
Wernicke’s Area
Left temporal lobe; Speech comprehension; Damage – fluid, nonsensical speech with no meaning
Depressants – Alcohol
Helps GABA shut down neurons & “relax” the drinker – “depress” the CNS; Impairments in balance & coordination; Produces euphoria & relieves anxiety; Impairs frontal lobe
Increase activity of CNS; Increase blood pressure, heart rate, alertness; Cause rapid behavior & thinking; Cocaine, Amphetamines, Caffeine
Stimulants – Cocaine
Euphoric rush of well-being; Decreases appetite; Increases DA & prevents its re-absorption; Increases NE & serotonin; Depresses respiratory system & can stop breathing; Can cause heart failure
Stimulants – Amphetamines
Manufactured in the lab; Increase energy & alertness & lower appetite in low doses; Produce a rush, intoxication, & psychosis in high doses; Causes emotional letdown; Increases DA, NE, serotonin
Stimulants – Caffeine
Most widely used stimulant; Increase release of DA, NE, serotonin; Increases arousal & motor activity & reduces fatigue; Increases heart rate but decreases blood supply
Causes powerful changes in sensory perception, including strengthening perceptions & producing illusions & hallucinations; LSD, Ecstacy
Hallucinogens – LSD
Lysergic acid diethylamide; Binds to neurons that receive serotonin & change activity; “Bad trips”; Long-term can cause psychosis or mood disorders, flashbacks
Hallucinogens – Ecstacy
MDMA; Synthetically produced drug that is technically a stimulant but has hallucinogenic effects; Causes serotonin & some DA to be released all at once in brain – dramatically increase levels & then deplete levels; Immediate psychological problems; Increased heart rate & blood pressure; Reduced sweat production & serotonin production
Produced from varieties of hemp plant; THC responsible for its effects; Most powerful is hashish, least is marijuana; Mixture of hallucinogenic, depressant, stimulant effects; Dangers include physical dependence, panic attacks, tar levels & lung disease
Constructive Addiction
When love is returned
Destructive Addiction
When love isn’t returned
Initial Stage of Withdrawal
Protest; Elevated levels of DA & NE that would be adaptive for any abandoned animal; Frustration – attraction
Secondary Stage of Withdrawal
Resignation/despair; Reduced activity in the subcortical dopmanic pathways