Chapter 8
SSRIs lock the transporter in an _____________ position that prevents serotonin from binding to the presynaptic plasma membrane receptor.
"outward-only"
Heritability of drug addiction is _________, with a two-to threefold increase in risk among adopted individuals who have one affected biological parent. Twin studies also indicate an inherited component to drug addiction.
0.4-0.6
Traditional methods of assessing multifactorial traits, such as adoption and twin studies, show a heritability of ________ for intelligence, indicating a high contribution from genetics.
0.5-0.8
Various forms of schizophrenia together affect about _____ percent of the world's population. Ten percent of affected individuals commit suicide.
1
The human brain contains _______ nerve cells or neurons, and at least ________ other cells called _________, which support and nurture the neurons.
100 Billion, Trillion, Neuroglia
In about _____ percent of people with autism, the condition is part of a syndrome, including single-gene disorders such as Rett syndrome , mitochondrial diseases and chromosomal conditions such as fragile X syndrome and Down syndrome
15
Genome-wide association studies have found more than _______ chromosomal regions that may include genes that contribute to drug craving
50
Each year, 35 million people try to quit smoking, yet only _________ percent of them succeed
7
Cataplexy
A sudden loss of voluntary muscle strength and control that is usually triggered by an intense emotion. It is considered the most dramatic form of narcolepsy.
What do Albert Einstein, Charles Darwin, Emily Dickinson, and Michelangelo all have in common?
Autistic Behaviors
What accumulates in and causes the plasma membranes of neuroglia to balloon out and forms a sheath that insulates the neuron, which speeds neuro-transmission? A. Enzymes B. Myelin C. DNA
B. Myelin
Explain Nicotine's effects at the cellular level.
Binding of nicotine to nicotinic receptors, which also bind the neurotransmitter acetylcholine, triggers release of dopamine from vesicles into the synapse. Some dopamine binds receptors on the postsynaptic (receiving) neuron and some dopamine reenters the presynaptic neuron through a dopamine transporter protein. Uptake of dopamine into the postsynaptic cell triggers pleasurable feelings.
_____________ looks at the evolution of treatments for and attitudes toward people with autism spectrum disorders
Bioethics
Certain variants of__________ are much more common among individuals with schizophrenia.
C4A
_________________ identifies genes that unrelated people with autism share (See Figure 8.10)
Comparison to a reference Genome
What are the three general strategies for isolating autism genes?
Comparison to a reference genome, Trio (Parent-child) analysis and recessive analysis
What is the cellular basis of behavior?
DNA contain genes that are transcribed into RNA which direct protein synthesis. These proteins include hormones, enzymes, neurotransmitters, neuromodulators and structural proteins. These proteins synthesized influence the behavior of the organism. For example, enzymes synthesize the hormone testosterone which influence sexual behavior.
Among the best-studied genetic causes of intellectual disability are _________ and _______________and one of the most familiar environmental causes is _____________________.
Down syndrome, Fragile X syndrome, fetal alcohol syndrome
_________ control the synthesis of neurotransmitters and their transport from the sending (_________) neuron across the synapse to receptors on the receiving (_________) neuron.
Enzymes, presynaptic, postsynaptic
What controls synthesis of myelin (a substance consisting of fats and proteins that coats neuron extensions called axons)
Genes
How do genes affect behavior?
Genes affect behavior by encoding diverse proteins that control the production and distribution of neurotransmitters.
What can be used to evaluate change in intelligence over a lifetime.
Genome-wide association study
What oversee broad functions such as sensation and perception, memory, reasoning, and muscular movements?
Networked Neurons
How are newer genetic technologies being used to discover gene variants that cause or contribute to intellectual disability?
New types of studies confirm the heritability established with older techniques, and also identify specific genes that contribute to or affect intelligence.
What controls neurotransmitters from sending to receiving neurons and also form the subunits of the receptors that bind neurotransmitters
Proteins
___________________ detects mutations in families with more than one affected child. (See Figure 8.10)
Recessive analysis
Branches from each of the 100 billion neurons in the brain form close associations, called __________ with 1,000 to 10,000 other neurons
Synapses
Pharmacogenetics
The study of the interrelation of hereditary constitution and response to drugs
Give a reason why researchers would study hypocretin/orexin and the molecules with which they interact?
To develop drugs used to treat insomnia
The two identifying characteristics of drug addiction are __________ and _______. Both contribute to the biological and psychological components of craving the drug
Tolerance and Dependence
________________ detects de novo mutations in a child. (See Figure 8.10) "These studies either find that parents are carriers of autosomal recessive or X-linked conditions, or that the autism in the child arose de novo".
Trio (parents-child) analysis
True or False: Bipolar disorder is rarer than depression. It affects 2.6 percent of the population and has a general population lifetime risk of 0.5 to 1 percent.
True
True or False: Proteins involved in drug addiction are those that ■ produce neurotransmitters, such as enzymes required for neurotransmitter synthesis; ■ remove excess neurotransmitters from the synapse (called reuptake transporters); ■ form receptors on the postsynaptic (receiving) neuron that are activated or inactivated when specific neurotransmitters bind; and ■ convey chemical signals in the postsynaptic neuron.
True
True or False: A systematic scrutiny of all studies of the genes behind bipolar disorder suggests as much as 10 percent of the genome—that is, hundreds of genes—are part of the clinical picture.
True
True or False: About twice as many women as men suffer from depression.
True
True or False: Schizophrenia may result from overactive synaptic pruning. Losing up to 2 billion brain synapses a day is normal as adulthood begins, but an acceleration in the process may lie behind schizophrenia.
True
True or False: Studies on dogs led the way to discovery of one human narcolepsy gene
True
True/ False: In many patients the course of schizophrenia plateaus (evens out) or becomes episodic. It is not a continuous decline, as is the case for dementia.
True
What is the evidence that sleep habits are inherited?
Twin studies of brain wave patterns through four of the five stages of sleep confirm a hereditary influence. The fifth stage, rapid eye movement or REM sleep, is associated with dreaming and therefore may indicate the input of experience more than genes.
Hypocretin
a neurotransmitter secreted by cells in the hypothalamus; helps regulate sleep-wake cycles, arousal and appetite
substance use disorder
a pattern of long-term maladaptive behaviors and reactions brought about by repeated use of a substance.
Mutation at a different part of the period 2 gene affects how early we tend to awaken. People with two adenines at this site (genotype AA) awaken _________ than people with two guanines (genotype GG). Heterozygotes, genotype AG, awaken at times between those of the two homozygotes.
an hour earlier
What modulates how brain cells respond to stimulation by binding to neurotransmitter receptors on presynaptic (sending) neurons, and are involved in response to stress and in social behavior
anandamide
Environmental triggers include prenatal exposures to rubella (German measles) and to the drug valproate. Evidence is accumulating that exposure to folic acid supplements late in gestation can cause epigenetic changes that increase the risk of _________
autism
fatal familial insomnia
autosomal dominant inherited disorder in which humans sleep normally at the beginning of their life but in midlife stop sleeping and, 7-24 months later, die. It is caused by infectious protein misfolding.
Amphetamines and LSD (lysergic acid diethylamide) produce their effects by _________________ on neurons that normally bind neurotransmitters called trace amines, which are found throughout the brain at low levels. LSD causes effects similar to the symptoms of_______________, suggesting that the trace amine receptors, which are ______________, may be implicated in the illness. LSD produces hallucinations, distorted perception, and heightened states of awareness, but is not _______________.
binding to receptors, schizophrenia, proteins, addictive
One in 68 children in the United States has autism, and ______ out-number ______ four to one. About 25 percent of affected children have seizures as they grow older. Although 70 percent of people with autism have intellectual disability, others may be very intelligent, and many are talented in science or the arts
boys, girls
Neurotransmitters
chemical messengers that cross the synaptic gaps between neurons
In late adolescence and in the early twenties, in all human brains, the dense bushes of ____________ emanating from brain neurons are trimmed, as part of normal development
dendrites
The human equivalents of the opiates are the __________ and _______ and the equivalent of THC is ______________.
endorphins and enkephalins, anandamide
maternal immune response to infections such as flu, birth complications, fetal oxygen deprivation, herpesvirus infection at birth, and traumatic brain injury or malnutrition in the mother are all ___________ ____________ contributing to schizophrenia
environmental factors
Genes and the environment contribute about _________ to depression
equally
Heritability of autism is ____________
high: about 0.90 (90% of vari-ability due to genetics).
Orexin
hunger-triggering hormone secreted by hypothalamus, it was found to be the same as the hypocretin receptor gene
Researchers discovered a "substantial genetic correlation" of 0.62 for intelligence at both ends of the life span which means what?
if someone was a smart 11-year-old, chances are excellent that he or she will be a smart senior citizen.
What can happen if there is a single DNA based gene mutation on chromosome 2, period 2?
interference with synchronization of the sleep-wake cycle with daily sunrise and sunset, (which is an example of a circadian rhythm.) This is seen in fatal familial insomnia
Each genetic syndrome accounts for________ percent of autism cases, but a significant percentage of individuals with each condition has autistic behaviors.
less than 1%
Symptoms of psychosis begin between ages 17 and 27 for ________ and 20 and 37 for _________.
males, females
Cells called __________ do the pruning, in response to C4A protein "tags" on the targeted synapses. __________ are a type of neuroglia that had been thought to function mainly in cleaning up cellular debris. When they are too active, perhaps in response to infection, a person loses too many synapses, neuron-to-neuron communication in the brain suffers, and the symptoms of schizophrenia appear.
microglia, microglia
abnormalities in either of two types of cell adhesion proteins found at synapses, called __________ and __________, are responsible for a small percentage of cases of autism
neurexins and neuroligins
On a molecular level, nicotine does damage through a five-part assembly of proteins called a ______________. The receptor normally binds the neurotransmitter acetylcholine, but it also binds the similarly-shaped nicotine molecule. Certain variants of the receptor bind nicotine very strongly, which triggers a nerve impulse that, in turn, stimulates the pleasurable dopamine release into the synapse. That may explain the addiction.
nicotinic receptor
A person who has an identical twin with schizophrenia has a 52 percent chance of __________ developing it.
not
The effects of cocaine seem to be largely confined to the ________, whereas alcohol affects the ______________.
nucleus accumbens, prefrontal cortex
The brain changes that contribute to addiction occur in parts called the __________, the __________, and the _________ which are part of a larger set of brain structures called the limbic system
nucleus accumbens, prefrontal cortex, ventral tegmental area
Three types of neurexins emanate from the "sending" _______________, and a neuroligin extends toward the neurexin from the "receiving" _________________.
presynaptic neuron, postsynaptic neuron
cytokines
proteins that cause inflammation and can subtly alter brain development.
The endorphins and enkephalins do what?
relieve pain
debilitating loss of the ability to organize thoughts and perceptions, which leads to a withdrawal from reality
schizophrenia
Antidepressant drugs called selective _________ _________ __________ __________ prevent pre-synaptic neurons from taking up serotonin from the synapse, leaving more of it available to stimulate the postsynaptic cell
selective serotonin reuptake inhibitors (SSRIs
A likely cause of depression is deficiency of the neuro-transmitter _______ in synapses.
serotonin
A heritability of 0.9 and empiric risk values indicate a ________ role for genes in causing schizophrenia
strong
Behavioral Genetics
study of hereditary influences and how it influences behavior and thinking
Daily rhythms such as the sleep-wake cycle are set by cells that form a "circadian pacemaker" in two clusters of neurons in the brain called the ____________ _____________.
suprachiasmatic nuclei
Synapse
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
intelligence
the mental potential to learn from experience, solve problems, and use knowledge to adapt to new situations
Depression: The genetic connection is that a protein in the plasma membrane of the presynaptic neuron, called the serotonin transporter, may function ___________ in depressed individuals, removing too much serotonin from the synapse.
too efficiently
Deciphering the genetic components of behavioral traits and diseases use what type of studies to identify responsible gene variants.?
traditional empiric risk determination, adoptee and twin study data, and exome and genome sequencing
