Psych Ch. 3 Kalat
Cerebellum
(Latin for "little brain") part of the hindbrain
The biological basis of drug abuse and dependence...
- Nearly all abused and addictive drugs increase activity at the dopamine receptors in the brain. - The release of dopamine increases, or its reuptake is inhibited, or dopamine-releasing neurons are stimulated and dopamine-inhibiting ones are hindered. - Dopamine works on a small brain area, the nucleus accumbens. central for attention and habit-formation.
Axons
- Send electrochemical messages to neighboring cells. - Most transmit information to dendrites or cell bodies of other neurons. - Many are covered with myelin, which speeds up transmission. - Single, long, thin, straight fibers with branches near tips
Forebrain
- The forebrain has a left and right hemisphere. - Each controls sensation and motor functioning on the opposite side. - They communicate with each other through a bundle of axons crossing between the corpus callosum.
3 parts of a neuron
1. Cell body (soma) with a nucleus and most of the organelles. 2. Dendrites - branching structures that receive transmissions from other neurons. 3. Axon - a single, long, thin fiber with branching tips.
Periphereal Nervous System subdivisions
1. The somatic nervous system is made up of the peripheral nerves that communicate with the skin and muscles. 2. The autonomic nervous system controls involuntary processes of our internal organs (digestive, for example.)
4 lobes of the cerebral cortex
1. occipital lobe (vision), 2. temporal lobe (hearing and some aspects of vision), 3. parietal lobe (body sensations), and the 4. frontal lobe (preparation for movement). Damage in the cerebral cortex produces specialized behavioral deficits.
How do neurons communicate?
A neuron communicates with another neuron by releasing a chemical called a neurotransmitter at a specialized junction called a synapse. A neurotransmitter can either excite or inhibit the next neuron, with varying durations of effect.
The cerebellum is important for behaviors that require...
Accurate timing
Synaptic Communication
After the message is sent the neurotransmitter detaches from the receptors. It may be reabsorbed by the axon that released it (reuptake), diffuse away, be removed as a waste product (metabolized), or remain in the synapse.
What is an action potential?
An impulse that flows down an axon by movement of chemical ions
Anxiolytics (tranquilizers)
Benzodiazepines, widely used to relieve anxiety, can also relax muscles and promote sleep. Anxiolytics and alcohol act by facilitating inhibitory synapses.
Biological basis of Benzodiazopine
Benzodiazopine transquilizers help GABA attach to its receptor
Biological basis of cocaine
Blocks reuptake of dopamine and serotonin after their release. Methylphenidate and many antidepressants do so also, but more slowly
Estimated distribution of the neurons in the adult human central nervous system:
Cerebral cortex and ass. areas: 12-15 billion neurons Cerebellum: 70 billion neurons Spinal cord: 1 billion neurons
Endorphins
Chemicals Produced BY the Brain That Bind to Opiate Receptors
Alcohol
Class of Molecules That Includes Methanol Ethanol, Propyl Alcohol (Rubbing Alcohol), and Others; Ethanol is the Type That People Drink
Synapses
Communication between neurons occurs at the synapses. Synapses are specialized junctions. Chemicals released at the synapse excite or inhibit neighboring cells, making action potentials more or less likely. Synaptic activity is crucial to brain function.
Which part of a neuron receives input from other neurons (ordinarily)? Which part sends messages to other neurons?
Dendrites receive input from other neurons. Axons send messages.
Depressants
Depressants decrease physiological arousal. - The most commonly used/abused depressants are alcohol and tranquilizers. - They facilitate the transmission of the neurotransmitter GABA. - Alcohol is a class of chemicals that includes methanol, ethanol, and propyl (rubbing) alcohol. - Ethanol is found in liquor, wine, and beer.
Left and right brain hemispheres
Each brain hemisphere controls the opposite side of the body. The left hemisphere of the human brain is specialized for language in most people. The right hemisphere is important for understanding spatial relationships and for interpreting emotional expressions.
What is meant by the all-or-none law?
Either the axon produces an action potential, or it doesn't.
In what way does the field of epigenetics blur the distinction between hereditary effects and environmental effects?
Epigenetic changes are alterations in gene expression caused by environmental influences
The action potential
Excitation that travels along an axon at a constant strength, no matter how far it travels. Information is conveyed along an axon by an action potential, which is regenerated without loss of strength at each point along the axon. - Unstimulated axons have a negative charge (-70 millivolts relative to outside)
Biological basis of alcohol
Facilitates GABA receptor
If someone has trouble recognizing faces despite normal vision in other regards, what is a possible explanation?
Fewer than average connections from the fusiform gyrus in the left temporal cortex
Alcohol and anxiolytic drugs (tranquilizers) facilitate synapses that release which transmitter?
GABA
What produces the symptoms of Parkinson's?
Gradual decay in a system of axons that release dopamine produces these symptoms - Symptoms can be managed in mild cases with the drug L-dopa. - It is synthesized into dopamine by the neurons.
Biological basis of amphetamine
Increases release of dopamine and seratonin. So does MDMA (ectasy)
THC, the active component of marijuana smoke, produces its behavioral effects by what action on neurons?
It decreases release of glutamate or GABA.
Which lobe is damaged if... A person has difficulty with fine movements with the right hand?
Left frontal lobe
Marijuana
Marijuana's active compound, THC, acts on abundant receptors. Marijuana acts on receptors on the presynaptic neuron, putting the brakes on release of both excitatory and inhibitory transmitters.
Narcotics
Narcotics cause drowsiness, insensitivity to pain, and decreased responsiveness to environmental stimuli. - Opiates are one common type of narcotic. - They derive from the opium poppy or can be synthesized artificially. - They create feelings of euphoria. - Once used up, intense withdrawal and a need to use again usually follows. - Endorphins bind to opiate receptors and stimulate dopamine production.
Types of cells in the nervous system:
Neurons Glia
Nerve Cell Growth
Neurons do not have a fixed anatomy. - Neurons constantly grow and shed dendrites and axons. - Usually this occurs in response to experience and learning.
In what parts of the adult human brain, if any, can new neurons form?
Only in the hippocampus and basal ganglia
Opiates
Opiate drugs bind to endorphin receptors in the nervous system. The immediate effect of opiates is pleasure and relief from pain.
Which lobe is damaged if... A person is unable to feel or locate the left side of her body?
Right parietal lobe
Compared to other cells of the body, neurons vary more widely in what aspect?
Shape
Stimulants
Stimulant drugs such as amphetamines and cocaine increase activity levels and pleasure by increasing the release, and decreasing reuptake, of dopamine and certain other neurotransmitters. - Free-base and crack cocaine enter the nervous system more rapidly, thus producing a more powerful "high" than does powder cocaine.
Biological basis of LSD
Stimulates receptor
Central and peripheral nervous systems
The central nervous system consists of the brain and the spinal cord. The peripheral nervous system consists of nerves that communicate between the central nervous system and the rest of the body.
Corpus callosum
The corpus callosum enables the left and right hemispheres of the cortex to communicate with each other. If the corpus callosum is damaged, the two hemispheres cannot share information
All-or-none Law
The fact that an axon cannot vary the strength or velocity of its action potentials
Hippocampus
The hippocampus is vital for memory processing. - Located near the temporal lobe
In the primary somatosensory cortex in the parietal lobe, the greatest amount of space is devoted to which parts of the body?
The most sensitive areas, such as the lips and hands
How do stimulant drugs such as cocaine affect neurons?
They block reuptake of dopamine and serotonin by the presynaptic neuron.
Why do many cold remedies interfere with sleep?
They decrease parasympathetic nervous system activity and increase sympathetic activity.
Tranquilizers
Tranquilizers were developed to help people relax and fall asleep. -They suppress epileptic seizures as well. - Barbiturates proved so addictive and dangerous that they are rarely prescribed today. - Benzodiazepines such as Valium and Librium, are milder (still highly addictive) drugs used for anxiety management.
blindsight
ability to point to or otherwise indicate the direction to a visual stimulus, without conscious perception of seeing anything at all
Occipital lobe
area of the cerebral cortex located at the rear of the head, specialized for vision
Central nervous system
brain and spinal cord
Medulla
brain area that controls some muscles of the head, some sensations from the head, and output to the stomach and intestines
Terminal bouton
bulge at the end of an axon from which the axon releases a neurotransmitter
Neuron
cells of the nervous system that receive information and transmit it to other cells by conducting electrochemical impulses
Glia
cells that support the neurons in many ways such as insulating them, synchronizing activity among neighboring neurons, and removing waste materials - They are 1/10th the size of the neurons, but about 10 times as numerous.
Plasticity
change as a result of experience
Epigenetics
changes in gene expression as a result of environmental influences, without modification of the DNA sequence
hormone
chemical released by glands and conveyed by the blood to alter activity in various organs
Neurotransmitter
chemical that activates receptors on other neurons
epilepsy
condition in which cells somewhere in the brain emit abnormal rhythmic, spontaneous impulses
Parkinson's Disease
condition that affects about 1 percent of people over the age of 50; the main symptoms are difficulty initiating voluntary movement, slow movement, tremors, rigidity, and depressed mood
Temporal lobe
cortical area located toward the left and right sides of the head, largely responsible for hearing and certain aspects of vision
electroencephalograph (EEG)
device that measures and amplifies tiny electrical changes on the scalp that reflect brain activity
magnetoencephalograph (MEG)
device that records magnetic changes
Opiates
either natural drugs derived from the opium poppy, or synthetic drugs with a chemical structure resembling natural opiates
Resting potential
electrical polarization across the membrane (or covering) of an axon
PET measures and fMRI measures .
glucose supply to brain areas ... oxygen use in brain areas
phenylketonuria (PKU)
inherited condition that, if untreated, leads to mental retardation
Myelin
insulating sheath that speeds the transmission of impulses along an axon
Postsynaptic Neuron
neuron on the receiving end of the synapse
Dopamine
neurotransmitter that promotes activity levels and reinforcement
Cerebral cortex
outer covering of the forebrain
Cell Body
part of the neuron that contains the nucleus of the cell
functional magnetic resonance imaging (fMRI)
procedure that uses magnetic detectors outside the head to compare the amounts of hemoglobin with and without oxygen in different brain areas
Neurons in the CNS...
process and interpret information and send commands to muscles, glands, and organs.
binding problem
question of how separate brain areas combine to produce a unified perception of an object
Physiological
relating to the branch of biology that deals with the normal functions of living organisms and their parts. BIOLOGICAL FUNCTION
autonomic nervous system
section of the nervous system that controls the organs
Corpus callosum
set of axons that connect the left and right hemispheres of the cerebral cortex
X chromosome
sex chromosome; females have two per cell and males have one
Synapse
specialized junction between one neuron and another
Chromosome
strands of hereditary material
amygdala
structure in the temporal lobe, responds strongly to emotional situations
Parietal lobe
structure just anterior (forward) from the occipital lobe, specialized for the body senses, including touch, pain, temperature, and awareness of the location of body parts in space
Hypothalamus
structure just below the thalamus, important for hunger, thirst, temperature regulation, sex, and other motivated behavior
Except for Novocain and related drugs that block action potentials, every drug with psychological effects acts at...
synapses
frontal lobe
the anterior (forward) pole of the brain, which includes the primary motor cortex, important for controlling fine movements
Stem cells
undifferentiated cells
Dendrite
widely branching structures of a neuron that receive input from other neurons