Neurons
Nerve cells, which are the basic units of this system; receive, integrate, and transmit information in the nervous system
Neural Networks
Circuits that are formed as a result of selective communication between neurons
Nervous System
Divided into two functional groups - Central Nervous System and Peripheral Nervous System
Central Nervous System
Consists of the brain and the spinal cord; organizes and evaluates the information from the PNS and directs the PNS to perform specific behaviors or make bodily adjustments
Peripheral Nervous System
Consists of all the other nerve cells in the rest of the body; transmits information to the CNS
Three basic types of neurons
Sensory (Afferent) Neurons, Motor (Efferent) Neurons, and Interneurons
Afferent (Sensory) Neurons
Detect information from the physical world and pass the information to the brain (usually through the spinal cord)
Somatosensory Nerves
Sensory nerves that provide information from the skin and muslces
Efferent (Motor) Neurons
Direct muscles to contract or relax, thereby producing movement (transmit signals from the brain to the body)
Interneurons
Communicate within local or short-distance circuits instead of the entire body
Four structural regions of neurons
Dendrites, Soma (cell body), Axon, and Terminal Buttons
Dendrites
Short, branchlike appendages that increase the neuron's receptive field and detect chemical signals from neighboring neurons
Soma (Cell Body)
Receives information from thousands of other neurons and is collected and integrated
Axon
A long, narrow outgrowth along which electrical impulses are transmitted
Terminal Buttons
Knoblike structures at the ends of axons
Synapse
The site where chemical communication occurs between neurons
Synaptic Cleft
Tiny gap between the axon of the "sending" neuron and the dendrites of the "receiving" neurons
Presynaptic (Postsynaptic)
The neurons in the chain of communication
Myelin Sheath
Encases and insulates electrical signals which travel quickly down the axon; made of glial cells (neuroglia/glia)
Nodes of Ranvier
Small gaps of exposed axon located between gila segments
Ion Channels
Located at gaps; allow negatively and positively charged molecules (ions) to pass in and out of the cell when the neuron transmits signals down the axon
Resting Membrane Potential
When a neuron is resting, the inside and outside are different electrically; the ratio of negative to positive ions is greater inside the neuron than outside it
Polarized
When a neuron has more negative ions inside than outside it
Two types of ions that contribute to a neuron's resting membrane potential
Sodium Ions and Potassium Ions
Sodium Ions
Allow only sodium ions to pass through the membrane
Potassium Ions
Allow only potassium ions to pass through the membrane
Sodium-Potassium Pump
Works to increase potassium and decrease sodium inside the neuron
Action Potential (Neural Firing)
Electrical signal that passes along the axon and causes the release of chemicals that transmit signals to other neurons
Two types of signals arrive at the dendrites
Excitatory Signals and Inhibitory Signals
Excitatory Signals
Depolarize (reduce polarization in) the cell membrane, increasing the likelihood that the neuron will fire
Inhibitory Signals
Hyperpolarize (increase polarization in) the cell, decreasing the likelihood that the neuron will fire
Propagation
Wave-like movement of the cell membrane's depolarization along the axon as a result of a firing neuron
All-Or-None Principle
A neuron fires with the same potency each time; doesn't fire weak or strong, how often it fires depends on the strength of stimulation
Presynaptic Neuron
Neuron that sends the signal
Postsynaptic Neuron
Neuron that receives the signal
Neurotransmitters
Chemical substances that carry signals across the synaptic cleft
Receptors
Specialized protein molecules located on the postsynaptic membrane that specifically respond to the chemical structure of the neurotransmitter available in the synapse
Three major events that terminate neurotransmitter's influence in synaptic cleft
Reuptake, Enzyme Deactivation, and Autoreceptors
Reuptake
Occurs when neurotransmitters are taken back into presynaptic terminal buttons
Enzyme Deactivation
Occurs when an enzyme destroys the neurotransmitter in synaptic cleft
Autoreceptors
Monitor how much neurotransmitter has been released into synaptic cleft
Agonists
Drugs and toxins that enhance the actions of neurotransmitters
Antagonists
Drugs inhibiting these actions
Neurotransmitters
Acetylcholine, Epinephrine, Norepinephrine, Serotonin, Dopamine, GABA, Glutamate, Endorphins, Substance P
Acetylcholine
Motor control over muscles; Learning, memory, sleeping, and dreaming (botox, alzheimer's)
Epinephrine
Energy ("fight or flight")
Norepinephrine
Arousal and vigilance (clarity of attention)
Serotonin
Emotional states and impulsiveness; Dreaming (low levels: sad and anxious moods, food cravings, aggressive behavior; treat depression, OCD, eating disorders, obesity)
Dopamine
Reward and motivation; Motor control over voluntary movement (Parkinson's)
GABA
Inhibition of action potentials; Anxiety reduction; Intoxication (through alcohol) (Epileptic seizures, anxiety disorders)
Glutamate
Enhancement of action potentials; Learning and memory
Endorphine
Pain reduction and reward
Substance P
Pain perception; Mood and anxiety
Monoamines
Epinephrine, norepinephrine, serotonine, and dopamine - regulate arousal, regulate feelings, and motivate behavior
Equipotentiality
The idea that all areas of the brain are equally important in cognitive activities such as problem solving and memory
Phrenology
The practice of assessing personality traits and mental abilities by measuring bumps on the human skull
Psychographs
Devices used to tell about participants' personalities based on the locations and sizes of bums on their heads
Broca's Area
Located in the front left side of the brain; crucial for the production of language
Spinal Cord
Responsible for the coordination of reflexes; carries sensory information up to the brain and carries motor signals from the brain to the body parts below to initiate action
Spinal cord is made of two distinct tissue types
Gray matter and white matter
Gray Matter
Dominated by neurons' cell bodies
White matter
Consists mostly of axons and the fatty sheaths that surround them
Brain Stem
Made of the medulla oblongata, the pons, and the midbrain; houses nerves that control basic functions of survival (heart rate, breathing, swallowing, vomiting, urination, and orgasm)
Reticular Formation
A network of neurons housed in the brain stem; projects into the cerebral cortex
Cerebral Cortex
Outer portion of the brain and affects general alertness; involved in inducing and terminating the different stages of sleep
Cerebellum
Little brain"; a large protuberance connected to the back of the brain stem; important for proper motor function; motor learning and motor memory, operates independently and unconsciously; cognitive processes - making plans, remembering events, using lan
Forebrain
Consists of two cerebral hemispheres (left and right)
Subcortical structures
Hypothalamus, Thalamus, Hippocampus, Amygdala, Basal Ganglia
Hypothalamus
The brain's mater regulatory structure; receives input from the entire body and brain and projects influence to the entire body and the brain; affects the function of many internal organs, regulating body temp, body rhythms, blood pressure, and blood gluc
Thalamus
The gateway to the cortex; receives almost all incoming sensory information (minus smell), organizes it, and relays it to the cortex
Hippocampus
Sea Horse"; storage of new memories; creates new interconnections within the cerebral cortex with each new experience; grows larger with increase use
Amygdala
Almond"; serves vital role in learning to associate things in the world with emotional responses, such as unpleasant food with disgust; located immediately in front of the hippocampus; enables us to overcome instinctive responses; intensifies function of
Basal Ganglia
System of subcortical structures crucial for planning and producing movement; receive input from the entire cerebral cortex; project input to motor centers of the brain stem; through thalamus, project input back to motor planning area of the cerebral cort
Nucleus Accumbens
Important for experiencing reward and motivating behavior
Limbic System
Border"; serves as the border between the evolutionary older parts of the brain (brain stem and cerebellum) and the evolutionary older parts of the brain (cerebral cortex)
Cerebral Cortex
Outer layer of the cerebral hemispheres and gives the brain its distinctive wrinkled appearance; site of all thoughts, detailed perceptions, and complex behaviors; enables us to comprehend ourselves, other people, and the outside world; source of culture
Each hemisphere of the cerebral cortex has four lobes
Occipital, Parietal, Temporal, and Frontal
Occipital Lobe
Vision; located at the back portion of the head
Primary Visual Cortex
Major destination for visual information
Parietal Lobe
Touch; left hemisphere receives touch information from the right side of the body and the right hemisphere receives information from the left side
Primary Somatosensory Cortex
A strip in the front part of the lobe, running from the top of the brain down the sides
Temporal Lobe
Hearing
Fusiform Face Area
Located at the intersection of the temporal and occipital lobes; more active when people look at faces
Frontal Lobe
Planning and movement
Primary Motor Cortex
Rearmost portion of the frontal lobes; includes neurons that project directly to the spinal cord to the body's muscles
Prefrontal Cortex
Rational activity; occupies about 30% of the brain (in humans); direct and maintain attention; keep ideas in mind while surrounded by distractions; develop and act on plans; sense of self and our capacity to empathize, etc
Lobotomy
Deliberate damaging of the prefrontal cortex
Corpus Callosum
Massive bridge of millions of axons, which connects the hemispheres and allows information to flow between them
Two primary components in the PNS
Somatic Nervous System and Autonomic Nervous System
Somatic Nervous System
Transmits sensory signals to the CNS via nerves; sends sensory information to spinal cord which then goes to the brain; CNS sens signals through the SNS to initiate movement
Autonomic Nervous System
Regulates the body's internal environment by stimulating glands and by maintaining internal organs; controls feelings like how full your stomach is and how anxious you feel
Two types of signals which travel from CNS to organs and glands
Sympathetic and Parasympathetic
Sympathetic
Prompt preparatory actions
Parasympathetic
Prompt to return to a normal state
Endocrine System
A communication network that influences thoughts, behaviors, and actions (similar to the nervous system)
Hormones
Chemical substances released into the bloodstream by the ductless endocrine glands (pancreas, thyroid, testes, ovaries)
Gonads
Main endocrine glands influencing sexual behavior; testes in males and ovaries in females
Pituitary "Master" Gland
Located at the base of the hypothalamus; governs the release of hormones from the rest of the endocrine glands
Releasing Factor
Causes the pituitary to release a hormone specific to that factor, and the hormone then travels through the bloodstream to endocrine sites throughout the body
DNA
Make up a chromosome; a substance that consists of two intertwined strands of molecules in a double helix shape
Genes
Segments of DNA strands
Genotype
An organism's genetic makeup which stays constant throughout life
Phenotype
An organism's observable physical characteristics which is always changing
Polygenic
When a population displays a range of variability for a certain characteristic such as height or intelligence
Gametes
The egg and sperm cells
Zygote
Resulting fertilized egg
Behavioral Genetics
The study of how genes and environment interact to influence psychological activity
Monozygotic (Identical) Twins
Result from one zygote (fertilized egg) dividing in two; each twin has the same chromosomes and same genes on each chromosome
Dizygotic (Fraternal) Twins
Result when two separately fertilized eggs develop in the mother's womb simultaneously
Plasticity
The brain continually changes over the course of development, throughout our constant stream of experience