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