2function Flashcards
cerebrum
associated with higher order
functioning, including the control of voluntary behavior.
Thinking, perceiving, planning, and understanding language
all lie within the cerebrum’s control.
cerebral cortex
The function of the cerebral cortex can be understood
by dividing it somewhat arbitrarily into zones, much like the
geographical arrangement of continents.
frontal lobe
responsible for initiating and
coordinating motor movements; higher cognitive skills, such
as problem solving, thinking, planning, and organizing; and
for many aspects of personality and emotional makeup.
parietal lobe
involved with sensory processes,
attention, and language. in the
parietal cortex, a number of different cortical areas are
concerned with the spatial representation of the body and of
visual and auditory targets around us. They seem to hold a
map of where our limbs are, and where interesting targets
are with respect to us.
occipital lobe
helps process visual information,
including recognition of shapes and colors.
temporal lobe
helps process auditory information and
integrate information from the other senses. Neuroscientists
also believe that the temporal lobe has a role to play in
short-term memory through its hippocampal formation, and in
learned emotional responses through its amygdala.
basal ganglia
The cerebral nuclei help coordinate muscle
movements and reward useful behaviors
thalamus
key part of the forebrain; passes
most sensory information on to the cerebral cortex after
helping to prioritize it
hypothalamus
key part of the forebrain; the control
center for appetites, defensive and reproductive behaviors, and
sleep-wakefulness
colliculi
of the midbrain (it has 2); These collections of neurons play a critical role
in visual and auditory reflexes and in relaying this type of
information to the thalamus.
hindbrain
includes the pons and the medulla
oblongata, which control respiration, heart rhythms, and
blood glucose levels.
cerebellum
The
cerebellum’s two hemispheres help control movement and
cognitive processes that require precise timing, and also play
an important role in Pavlovian learning.
spinal cord
receives sensory information from all parts of the body below the head. It uses this information for reflex
responses to pain, for example, and it also relays the sensory
information to the brain and its cerebral cortex. In addition,
the spinal cord generates nerve impulses in nerves that control
the muscles and the viscera, both through reflex activities and
through voluntary commands from the cerebrum.
myelin sheath
accelerates the
transmission of electrical signals along the axon
glia
perform many jobs. Researchers have known
for a while that glia transport nutrients to neurons, clean
up brain debris, digest parts of dead neurons, and help hold
neurons in place
trophic factors
Researchers have discovered several
small proteins in the brain that act as trophic factors, substances
that are necessary for the development, function, and survival
of specific groups of neurons.
opioid peptides
The precise role of the naturally
occurring opioid peptides is unclear. A simple hypothesis is
that they are released by brain neurons in times of stress to
minimize pain and enhance adaptive behavior
sex hormones
the increased levels of testosterone in males and
estrogen in females act on the hypothalamus and pituitary
to decrease the release of FSH and LH. The increased levels
of sex hormones also induce changes in cell structure and
chemistry, leading to an increased capacity to engage in
sexual behavior. Sex hormones also exert widespread effects
on many other functions of the brain, such as attention,
motor control, pain, mood, and memory.
CO
exact functions for carbon monoxide have
not been determined
NO
nitric oxide
neurotransmission governs erection in the penis. In nerves
of the intestine, it governs the relaxation that contributes
to the normal movements of digestion. In the brain, nitric
oxide is the major regulator of the intracellular messenger
molecule cyclic GMP. In conditions of excess glutamate
release, as occurs in stroke, neuronal damage following the
stroke may be attributable in part to nitric oxide.
prostaglandins
These very small and
short-lived molecules have powerful effects, including the
induction of a fever and the generation of pain in response
to inflammation. Type of lipid messenger. Prostaglandins enhance
the sensitivity of receptors to tissue damage and ultimately
can induce more intense pain sensations. prostaglandins are inhibited by aspirin.
endocannabinoids
These (lipid; membrane-derived) messengers control the
release of neurotransmitters, usually by inhibiting them,
and can also affect the immune system and other cellular
parameters still being discovered. Endocannabinoids play an
important role in the control of behaviors. They increase in
the brain under stressful conditions
ATP
ATP is present throughout the cytoplasm of all cells.
norepinephrine binds to receptors on neuron’s surface –> receptor activated, binds G protein on the inside of the membrane –> activated G protein causes the enzyme adenylyl cyclase to convert ATP to cAMP, the 2nd messenger –> cAMP
exerts a variety of influences within the cell, ranging from
changes in the function of ion channels in the membrane to
changes in the expression of genes in the nucleus
second messengers
After the action of
neurotransmitters at their receptors, biochemical
communication within cells is still possible. Substances that
trigger such communication are called second messengers.
Second messengers convey the chemical message of
a neurotransmitter (the first messenger) from the cell
membrane to the cell’s internal biochemical machinery.
second messengers are also
thought to play a role in
the manufacture and release of neurotransmitters and in
intracellular movements and carbohydrate metabolism in the
cerebrum — the largest part of the brain, consisting of two
hemispheres. Second messengers also are involved in growth
and development processes. In addition, the direct effects
of second messengers on the genetic material of cells may
lead to long-term alterations in cellular functioning and,
ultimately, to changes in behavior.
nicotine
acts through the well-known acetylcholine
nicotinic receptor. This drug can act as both a stimulant and a sedative. Nicotine stimulates the adrenal glands, and the resulting discharge of epinephrine causes a “kick” — a sudden release of glucose paired with an increase in blood pressure, respiration, and heart rate. In addition, nicotine releases dopamine in the brain regions that control motivation, which is one reason that people continue to smoke.
ethanol (general, low vs high)
Ethanol, the active ingredient in alcoholic beverages,
is a seductive drug. At first, it reduces anxiety, tension,
and behavioral inhibitions. In low doses, it may act as a
stimulant, but at higher doses, it acts as a depressant. In both
cases, it significantly alters mood and behavior. Too much
alcohol can also cause heat loss and dehydration
ethanol (neurotransmitters)
The drug, which is easily absorbed into the bloodstream
and the brain, affects several neurotransmitter systems. For
example, alcohol’s interaction with the gamma-aminobutyric
acid (GABA) receptor can calm anxiety, impair muscle
control, and delay reaction time. At higher doses, alcohol
also decreases the function of N-methyl-d-aspartate
(NMDA) receptors, which recognize the neurotransmitter
glutamate. This interaction can cloud thinking and
eventually lead to coma
THC
In radioactive tracing studies, scientists found that
tetrahydrocannabinol (THC), the active ingredient in
marijuana, binds to specific receptors called cannabinoid
receptors, many of which coordinate movement. This may
explain why people who drive after they smoke marijuana
are impaired. The hippocampus, a structure involved with
memory storage and learning, also contains many receptors
for THC. This finding provides some insight into why heavy
users or those intoxicated on marijuana have poor short-term
memory and problems processing complex information.
opiates
Opiates increase the amount of dopamine released in
the brain reward system and mimic the effects of endogenous
opioids (opioid peptides).
heroin
Heroin injected into a vein reaches the brain in 15
to 20 seconds and binds to opiate receptors found in many
brain regions, including the reward system. Activation of
the receptors in the reward circuits causes a brief rush of
intense euphoria, followed by a couple of hours of a relaxed,
contented state.
crack
In 2009, in the United States, an estimated 4.8 million
people age 12 and older had abused cocaine.
psychostimulants
This class of drugs includes cocaine and amphetamines. The key biochemical factor underlying
the reinforcing effects of psychostimulant drugs is their
ability to greatly elevate the brain chemical dopamine
in specific brain regions, such as the nucleus accumbens.
Alterations in dopamine activity in the accumbens,
induced by chronic cocaine intake, are thought to result
in a progressively increasing motivation to take the drugs,
eventually leading to addiction.
rohypnol
When mixed with
alcohol, rohypnol can incapacitate victims and prevent them
from resisting sexual assault. Rohypnol may be lethal when
mixed with alcohol and other depressants.
MDMA
aka ecstasy. a synthetic psychoactive drug with hallucinogenic
and amphetamine-like properties. Users encounter problems
similar to those found with the use of amphetamines and
cocaine. Recent research also links chronic ecstasy use to
long-term changes in those parts of the brain critical for
thought, memory, and pleasure.
GHB
Since about 1990 in the United States, GHB has
been abused for its euphoric, sedative, and anabolic
(body-building) effects. It, too, has been associated with
sexual assault.
special K
Ketamine is another central nervous system
depressant abused as a date-rape drug. Ketamine, or “Special
K,” is a fast-acting general anesthetic. It has sedative,
hypnotic, analgesic, and hallucinogenic properties. It is
marketed in the United States and a number of foreign
countries as a general anesthetic — a drug that brings about
a reversible loss of consciousness — in both human and
veterinary medical practice
apoE
Apolipoprotein E (apoE), which influences susceptibility for Alzheimer’s later in life, exists in three forms. The variant known as APOE epsilon 4 is clearly associated with enhanced risk.
amyloid genes
These genes encode beta and gamma
secretases, which cut amyloid peptide from a larger protein.
The amyloid peptide is then released from the neuron into
the space around synapses, where it can accumulate and form
Alzheimer’s disease plaques. Amyloid-destroying enzymes,
known as alpha secretases, break up the amyloid peptide,
preventing amyloid accumulation.
ALS
affects
neurons that control voluntary muscle movements such as
walking. For reasons that are not completely understood,
motor neurons in the brain and spinal cord begin to
disintegrate. Because signals from the brain are not carried
by these damaged nerves to the body, the muscles begin to
weaken and deteriorate from the lack of stimulation and
resulting disuse.
brain tumor vaccines
vaccines created from
the patient’s own tumor combined with substances that
boost the immune system or kill tumor cells
monoclonal antbodies
hone in on receptors on the surface of
the tumor cells
anti-angiogenic therapy
during which the
tumor’s blood supply is restricted
brain tumor immunotherapy
uses the body’s own immune system against the tumor
brain tumor gene therapy
delivers bioengineered genes to the
cancer cells to kill them
brain tumor targeted delivery + example
targeted delivery of antibodies, toxins, or growth-inhibiting
molecules that attach specifically to the tumor cells and
interfere with their growth. A scorpion-derived toxin called
chlorotoxin, which interferes with the spread of the tumor,
has shown promise in clinical studies. This therapy extended
life expectancy significantly
MS
an autoimmune disease in which the body’s natural
defenses attack the myelin sheath covering the axons of
neurons in the central nervous system. While neuroscientists
do not know what causes this autoimmune assault, they have
discovered that the loss of myelin results in damage to the nerve
fibers. In some instances, the damage may be so severe that
the nerve fiber deteriorates.
how does MS get its name?
Following loss of myelin, the axon’s sheath is either repaired
or replaced by scars, or scleroses, of hardened patches of tissue.
Scarring is usually associated with further degeneration of the
nerve fibers. Areas of disease activity, called lesions or plaques,
appear in multiple places within the central nervous system.
HIV numbers
In 2009, about 2.5 million people worldwide became
infected with human immunodeficiency virus (HIV); 33
million are now living with HIV.
As a last resort to reduce increased intracranial pressure,
part
of the skull may be removed to allow the brain to swell, a
procedure known as a decompressive craniectomy.
Contusions can
be troubling because
they can increase pressure as well as
contribute to the development of post-traumatic epilepsy.
analgesia
refers to the loss of pain sensation.
local anesthesia
Local anesthetics temporarily interrupt the action of all
nerve fibers, including pain-carrying ones, by interfering
with the actions of sodium channels.
Tylenol
Acetaminophen, the active
ingredient in Tylenol, has analgesic properties but does not
reduce inflammation.
NGF
nerve growth factor, a type of trophic factor. slows the destruction of neurons that use
acetylcholine. also holds promise for
slowing the memory deficits associated with normal aging.
Nogo-A
Using antibodies
that override the effect of Nogo-A, a protein that inhibits nerve regeneration, Swiss researchers succeeded in getting
some nerves of damaged spinal cords to regrow in rats and
monkeys. recently injured spinal cord injury patients are being
treated with anti-Nogo-A antibodies in a clinical trial.
engineered antibodies
It is sometimes possible
to trick the immune system into attacking those proteins
that cause neurological diseases by “vaccinating” patients against them. Another new approach
combines genetic engineering with immunology to engineer
antibodies or fragments of antibodies that can bind to and
alter the disease characteristics of specific proteins. These
therapies could be delivered either as proteins or as genes.
high-throughput screening
Thousands of small-molecule drug candidates can
be tested using high-throughput screening, during which
hundreds or thousands of compounds are tested to find those
with the desired cellular effect.
declarative memory
Our ability to learn
and consciously remember everyday facts and events is called
declarative memory.
neural induction
signaling
molecules released by the mesoderm turn on certain genes and turn off others, triggering
some ectoderm cells to become nerve tissue in a process called
neural induction. Subsequent signaling interactions further
refine the nerve tissue into the basic categories of neurons or
glia (support cells), then into subclasses of each cell type. The
remaining cells of the ectoderm, which have not received the
signaling molecules diffusing from the mesoderm, become skin.
sonic hedgehog
a particular signaling molecule,
called sonic hedgehog, is secreted from mesodermal tissue
lying beneath the developing spinal cord. As a result, the
adjacent nerve cells are converted into a specialized class of
glia. Cells that are farther away, however, are exposed to lower
concentrations of sonic hedgehog, so they become the motor
neurons that control muscles. An even lower concentration
promotes the formation of interneurons, which relay messages
to other neurons, not muscles.
amblyopia
a condition
in which the vision of one eye is greatly reduced because the
eyes do not work well together; has the best outcome when
it is started early in life, before the age of eight. During this
period of time, visual experiences guide the development
of the visual circuits. After the critical period comes to an
end, the circuits cannot be easily modified.
microdialysis
researchers use a technique called
microdialysis to measure the amount of a particular brain
chemical found in a specified area of the brain
electrophysiology
The study of the electrical properties of neurons is called
electrophysiology.
potentiation
long-term potentiation, the
cellular event that makes learning and memory possible. the discovery of this relied on electrophysiology
genetic linkage studies
Genetic linkage studies, which studied families and
large groups of unrelated people diagnosed with specific
conditions, made it possible to find the chromosomal
location of many genes.
chromosome microarrys
Newer techniques, called
chromosome microarrays, look carefully at the overall
chromosome makeup of a person and find out if segments of
chromosomes, perhaps involving multiple genes, are missing
(called deletions) or present in more than the usual amount
(called duplications).
HTT
the
gene that is altered in patients diagnosed with Huntington’s
disease
RB1
causes inherited retinoblastoma
retinoblastoma
a
rare, highly malignant, childhood eye tumor that can lead
to blindness and death
DMD
X-linked gene DMD,
responsible for Duchenne muscular dystrophy, a progressive
muscle disease.
Walker-Warburg syndrome
In some cases, mapping techniques have
shown that one condition may actually be due to mutations
in any one of a group of genes. This is the situation with a
condition called Walker-Warburg syndrome, which causes
severe problems involving the brain, eyes, and muscles,
leading to death in infancy or early childhood. Thus far, at
least five genes are known to be associated with this disease,
with still others yet to be discovered.
LIS1
scientists have identified a gene called LIS1 that helps tell
the brain how to grow. People with mutations in the LIS1
gene have smoother brains than normal and may have
seizures. In addition, severe intellectual disability is common.
However, the parents of these individuals do not have mutations in their LIS1 genes, so there is a very low chance
of other children of those parents having the same diagnosis.
“next generation” sequencing
This testing is expected
to uncover the functional sequence of all 20,000 or more
human genes (collectively called the exome) as well as the
remaining associated DNA that is thought to influence or
regulate these genes (together with the exome, this is called
the genome) for each person studied. So far, such studies
have revealed numerous types of genetic variants, making for
more variability in human genes than initially recognized.
Kabuki syndrome
causes congenital intellectual disabilities
along with certain abnormal facial features. Despite being
a distinctive condition, Kabuki syndrome long escaped
efforts to identify its genetic underpinnings.
how was therapy for strabismus developed?
Information from research in cats and monkeys has
improved the therapy for strabismus
sleep stage 1
over the course of the first hour or so
of sleep, the brain progresses through a series of stages during
which brain waves slow down. This period of slow wave sleep is
accompanied by relaxation of the muscles and the eyes. Heart
rate, blood pressure, and body temperature all fall.
stage 2 sleep
- REM, characterized by neocortical EEG waves similar to
those observed during waking. , accompanied by atonia (paralysis of the body’s muscles) - active dreaming
- men have erections
- Heart rate, blood pressure, and
body temperature become much more variable
sleep apnea: characteristics
Obstructive sleep apnea occurs as sleep deepens and
the airway muscles in the throat relax to the point
of collapse, closing the airway. The individual has
difficulty breathing and wakes up without entering
the deeper stages of slow wave sleep.
sleep apnea: effects
This condition
can cause high blood pressure and may increase the
risk of heart attack. Increased daytime sleepiness that
results from sleep apnea can lead to an increased risk of daytime accidents, especially automobile accidents.
sleep apnea: treatments
may include a variety of strategies to reduce
airway collapse during sleep. Whereas simple things
like losing weight, avoiding alcohol and sedating drugs
prior to sleep, and avoiding sleeping on one’s back
can sometimes help, most people with sleep apnea
require devices that induce continuous positive airway
pressure to keep the airway open. One such device
is a small mask that fits over the nose to provide an
airstream under pressure during sleep. In some cases,
surgery is needed to correct the airway anatomy.
periodic limb movements of sleep
are intermittent
jerks of the legs or arms that occur as the individual
enters slow wave sleep. These movements can cause
arousal from sleep. more common in people with Parkinson’s disease, and
both can be treated with drugs for Parkinson’s or with
a benzodiazepine called clonazepam.
REM behavior disorder
related to periodic limb movements of sleep. occurs when muscles fail to become
paralyzed during REM sleep, As a result, people
literally act out their dreams by getting up and moving
around. more common in people with Parkinson’s disease, and
both can be treated with drugs for Parkinson’s or with
a benzodiazepine called clonazepam.
narcolepsy
the
switching mechanisms controlling the transitions
into sleep, particularly REM sleep, do not work
properly.People with narcolepsy have sleep attacks during
the day, in which they suddenly fall asleep.
subparaventricular nucleus
the
suprachiasmatic nucleus provides signals to an adjacent brain
area, called the subparaventricular nucleus, which in turn
contacts the dorsomedial nucleus of the hypothalamus. The
dorsomedial nucleus then contacts the ventrolateral preoptic
nucleus and the orexin neurons in the lateral hypothalamus. It is
these neurons that directly regulate sleep and arousal.
voluntary nervous system
sends messages to muscles so that we may
respond to sensory information
cortisol
- glucocorticoid that promotes energy replenishment and efficient
cardiovascular function. - Cortisol levels, which vary naturally over a
24-hour period, peak in the body in the early-morning hours
just before waking. This hormone helps produce a wake-up
signal, turning on appetite and physical activity
working memory
When we have new experiences, information initially
enters working memory, a transient form of declarative
memory.
semantic memory
a form of declarative knowledge
that includes general facts and data
episodic memory
Our memories of specific personal experiences
that occurred at a particular place and time are called
episodic memories.
procedural memory
Nondeclarative knowledge,
the knowledge of how to do something, often called
procedural memory, is expressed in skilled behavior and
learned habits.
CREB
In addition, cAMP activates
another molecule, called cAMP-response element binding
protein (CREB). CREB operates within the nucleus of
the neuron to activate a series of genes, many of which
direct protein synthesis. Among the proteins produced are
neurotrophins, which result in growth of the synapse and
an increase in the neuron’s responsiveness to stimulation.
aphasias
language disorders
nonfluent aphasias
a syndrome in which speech production abilities are
impaired. Speech output is slow and halting, requires effort,
and often lacks complexity in word or sentence structure.
Although speaking is impaired, nonfluent aphasics still
comprehend heard speech, although structurally complex
sentences may be poorly understood.
fluent aphasia
comprehension of heard speech is impaired. Speech output,
although of normal fluency and speed, is often riddled
with errors in sound and word selection and tends to be
unintelligible gibberish. Wernicke’s aphasics can often comprehend bits and pieces of
a spoken utterance, as well as isolated words.
word deafness
a profound inability
to comprehend auditory speech on any level. patients with
word deafness are functionally deaf for speech, lacking the
ability to comprehend even single words, despite being able
to hear sound and even identify the emotional quality of
speech or the gender of the speaker.
sensory-motor circuit for speech
is thought to help the systems for speech recognition
and speech production communicate with each other.
This circuit is involved in speech development and
is thought to support verbal short-term memory.
neurogenesis
scientists have discovered that
the adult brain continually generates new nerve cells — a process known as neurogenesis. Interestingly, one of the most
active regions for neurogenesis in the brain, the hippocampus,
is also an area heavily involved in learning and memory.
plasticity
The brain possesses the ability
to modify neural connections to better cope with new
circumstances.
growth cones
Growth cones, enlargements on the axon’s tip, actively
explore the environment as they seek out their precise
destination. Researchers have discovered many special
molecules that help guide growth cones. Some molecules
lie on the cells that growth cones contact, whereas others
are released from sources found near the growth cone. The
growth cones, in turn, bear molecules that serve as receptors
for the environmental cues. The binding of particular signals
with receptors tells the growth cone whether to move
forward, stop, recoil, or change direction.
saltatory conduction
In between
the myelin are gaps, called nodes of Ranvier, that are not
covered in myelin. The electrical signal moves faster over
the insulated portion, jumping from one node to another.
This phenomenon, known as saltatory conduction (the word
“saltatory” means “to jump”), is responsible for the rapid
transmission of electrical signals.
myelination
the wrapping of axons by extensions
of glia, increases the speed at which signals may be sent
from one neuron to another by a factor of up to 100x. This
advantage is due to how the sheath is wrapped. The process of myelination
occurs throughout the lifespan.
critical periods
the paring down
of connections occurs in large part during critical periods
in early postnatal life. During these moments in time, the
developing nervous system must obtain certain critical
experiences, such as sensory, movement, or emotional input,
to mature properly. Such periods are characterized by high
learning rates as well as enduring consequences for neuronal
connectivity. It is important to note that
there are multiple critical periods, organized sequentially,
as individual brain functions are established.
experience-expectant plasciticty
Experience-expectant plasticity refers to the integration
of environmental stimuli into the normal patterns of
development. Certain environmental exposures during limited
critical, or sensitive, periods of development are essential for
healthy maturation.
Experience-Dependent Plasticity
the continuing process of the creation and organization of neuron connections that occurs as a result of a person’s life experiences
