WSU PSY2250 exam 2, Ch. 3, 4, 5, & 6

A sensory prosthesis is:

a mechanical device containing sensory detectors that interface with appropriate sensory areas of the brain

In behavioral economics, the ____ refers to the distribution of resources that maximizes the individuals subjective value or satisfaction

bliss point

The distributed model to respond to a blue- light and then presents it with a blue-green light, it responds to the to the blue-green light because:

both lights activate some of the same nodes in the internal representation layer

Regarding CS modulation theories versus US modulation theories, it seems to be that ____ is/are correct

both theories

habituation to a stimulus:

can carry risks

on an acquired-equivalence task, people with schizophrenia:

can learn the initial discrimination by cannot generalize in the third phase

if a pigeon is being trained to peck at a disc for a food reward, which delay between pecking and receiving that reward will lead to the fastest learning?

0 seconds

A regular drug user can have elevated reaction to their usual drug if they take that drug in a new environment. In this example, the familiar environment in which the drug is normally taken is a:

CS

The statements that follow are true about what cortices?There is a specific cortical region dedicated to processing information from each sensory modality. Each region of the cortex responds preferentially to a particular type of stimulus. neighboring cortical regions respond to similar stimuli.

primary sensory cortices

Lauren is trying to stop her son from banging his spoon on the table during meals by praising him whenever he uses his spoon to eat his food. This is an example of:

reinforcement of alternative behaviors

In people with schizophrenia, anti-psychotic medications appear to:

remove some of the acquired-equivalence deficits

It is believed that he mechanisms of habituation documented in Aplysia occur in other species because:

repeated stimulation of sensory neurons in other species causes a reduction in neurotransmitter release

The matching law of choice behavior states that, given two responses that are reinforced on different VI schedules, an organism will:

respond in order to approximately match the relative rate of reinforcement for each response

If one has been reading for hours and the idea of taking a break to lean the room sounds very attractive, one is exibiting:

response deprivation

Chloe learned that babies who cry a lot also have trouble sleeping. when she later learned that babies who have trouble sleeping tend to be highly intelligent, she inferred that babies who cry a lot are also highly intelligent. This relationship is an example of:

sensory preconditioning

Training in which presentation of two stimuli together as a compound results in a later tendency to generalize what is known about one of these stimuli to the other is known as:

sensory preconditioning

Compared with the generalization gradient that is observed when no discrimination training is given, the generalization gradient that is observed after discrimination training is:

steeper

___ reflect one's tendency to generalize in order to predict future events

stereotypes

The mediation behavior through responses to cues in the world is known as:

stimulus control

The form in which information about stimuli is encoded within a model or brain is:

stimulus representation

It is true that neurons code the expectation as well as the specific outcome regarding what?

the orbitofrontal cortex

A baseball player gets a hit approximately every third time at bat. this is an example of a ____ schedule of reinforcement

variable-ratio

a division or class of entities in the world is referred to as a:

category

People with long-term addictions to cocaine or amphetamine:

do not receive the same "high" that they did in the early stages of addiction

According to Gluck and Myers' model, the hippocampal region should be most active:

early in training

Lesions of the hippocampal region lead to:

enhanced latent inhibition

According to he phenomenon of conditioned compensatory response, drug addicts develop a tolerance to their drugs because:

environmental cues elicit CRs that counteract the effect of the drug

If a pigeon is allowed to peck as the switch in order to receive food whenever it chooses, this is an example of which type of paradigm?

free-operant

Lucy was bitten by a small white dog and now she has a fear of all dogs, regardless of their size or color. This is an example of:

generalization

The transfer of past learning to new situations and problems is known as:

generalization

____ and ____ are fundamental tools for ones survival

generalization: stereotypes

Negative patterning is difficult to learn because it requires the organism to suppress its tendency to:

generalize

The eye blink CR seems to:

gradually increase in strength over several trials

According to the law of effect, which circumstance would lead to a weakening of the association between stimulus and response?

grounding a teenager for staying out too late

Removing the ____ abolishes conditioned responses.

interpositus nucleus

The final exit point of CR information from the cerebellum is/are the:

interpositus nucleus

The temporal gap between the onset of CS and the onset of the US is known as:

interstimulus interval

Regarding the use of constraint-induced movement therapy to treat learned non-use:

it exploits mechanisms of cortical plasticity

The hippocampus:

lies just beneath the temporal lobe in primates

Sleep experts routinely advise good sleep hygiene that consist of:

limiting one's bedroom stimulus

Classical conditioning in aplysia appears to involve:

long-term changes in the number of synapses and short-term intracellular changes

Anatomical changes in neural circuits (such as growth or loss of synapses) seem to be responsible for ____ forms of memory; intracellular changes (such as increase or decrease in neurotransmitter vesicles) seem to be responsible for ____ forms of memory

long-term; short-term

When rats learn to run through mazes, they:

make substantial use of the visual cues in the environment

Repeated exposures to high stress levels during development, for example, can increase chances for depression later in life and also puts children at risk of developing anxiety disorders such as:

obsessive compulsive disorder

The process by which an organism learns to produce a specific response in order to avoid or obtain an outcome is:

operant learning

When a more salient cue within a compound acquires more of the share of the attention and learning than the less salient cue, it is known as:

overshadowing

Research has shown that, in the cortexes of opossums blinded at birth:

within the visual area some neurons responded to auditory or somatosensory stimuli

The unconditioned response occurs:

without any training or conditioning

When the eye blink reflex is conditioned using a tone, the conditioned response is:

Blinking in response to the tone

When a drug addict is in the environment where they usually take drugs they will typically feel a craving for the drugs. This craving is a:

CR

When a conditioned compensatory response occurs, the:

CR is the opposite of the UR

According to CS modulation theories such as that of Mackintosh, latent inhibition occurs because the:

CS is ignored because it doesn't predict anything reliably

If a US occurs just as often without the tone as it does in the presence of the tone, then little or no conditioning will accrue to the tone. This would suggest that animals are sensitive to ____ of the potential CS and the US.

Contingency

Studies of ____ have been enormously important for understanding the biology.

Drosophilia (fruit flies)

____ suggests that both sensitization and habituation occur in response to every stimulus presentation, and that it is summed combination of these two independent processes that determines the strength of responding.

Dual process theory

A decrease in the strength or occurrence of a behavior after repeated exposure to the stimulus that produces the behavior is called:

Habituation

When one first enters a bakery, one notices all the wonderful smells, but after a few minutes it is unnoticed. This is an example of:

Habituation

the MIlkwaukee police noticed a putrid smell in Jeffery Dahmer's apartment, but because they had experienced many smelly apartments they did not investigate the source of the smell. This is an example of:

Habituation

when Michelle and Patrick met, she was bothered by his height, but after 15 years of marriage she barely notices it anymore. This is an example of:

Habituation

In what way does operant conditioning differ from classical conditioning?

In classical conditioning, the consequence arrives regardless of the animal's behavior, while in operant conditioning, it only arrives once the animal has made a response

The theory that states that the probability of a response will increase or decrease depending on the outcome that follows is:

the law of effects

Regarding sexual arousal in humans, do males or females habituate more strongly than their counter parts?

Males habituate more strongly than females to sexual arousal

_____ exposure produces the fastest habituation, and _____ exposure produces the longest lasting habituation

Massed; spaced

People are generally better at distinguishing individuals belonging to racial groups that they frequently encounter than individuals belonging to racial groups with whom they don't interact. This is an example of:

Mere exposure learning

Rats that are exposed to circles and triangles for a month can learn to discriminate between these two shapes more quickly than rats not exposed to the shapes. This finding demonstrates:

Mere exposure learning

A roller coaster ride elicits an initial feeling of fear followed by a feeling of exhilaration. After repeated experiences, the initial fear responses may become weaker, whereas the rebound responses grow stronger. This process is called ____ theory

Opponent process

Which is an example of appetitive conditioning?

Pavlov's conditioning of salivation in dogs

Learning in which repeated experience with a set of stimuli makes those stimuli easier to distinguish is known as:

Perceptual learning

Professional wine tasters can easily distinguish between subtly different wines. This is an example of:

Perceptual learning

A neuron that responds only when a rat is in a particular location is called a ____, and the preferred location is called the ____.

Place cell; place field

In some situations, arousal can have severe consequences, In the most severe cases, a single highly emotional event can lead to life-long amplification of emotional responses to a wide range of stimuli. This is referred to as:

Post-traumatic Stress Disorder

The textbook describes a study in which blue jays were quicker and more accurate at detecting a particular species of moth if they had recently detected other members of the species. This result demonstrates:

Priming

In mammals, the two sites where information about the CSuUS association can be stored in the cerebellum are the ____ and the ____

Purkinje cells in the cerebellar cortex: interpositus nucleus

The dorsal striatum seems to be particularly important form learning which association(s) in operant conditioning?

S-R

When experiences with an arousing stimulus lead to a stronger-than-normal response to a later stimulus, this is known as:

Sensitization

If a person is nervous about climbing trees because of a tree fall in the past that resulted in a broken leg, the person may have become:

Sensitized

A conditioning chamber called a ____ delivers reinforcement or punishment automatically whenever an animal makes a particular response

Skinner Box

Susan's daughter was constantly calling "mommy" throughout the day, until Susan eventually barely noticed her daughter's calls. The next day, when Susan's daughter called "mommy" for the first time, Susan did hear her. This is an example of:

Spontaneous Recovery

____ is a set of beliefs about the attributes of the members of a group

Stereotype

Suppose a child grows up hearing his parents making derogatory comments about African Americans, and eventually the child comes to have negative feelings about African Americans. What is the conditioned stimulus?

The African Americians

The sontaneous recovery of a CR suggests that:

The CR is not gone after extiction

Suppose a baby is presented repeatedly with the color yellow. How could this be an example that habituation is stimulus specific in this case?

The baby's orienting to yellow decreases, and then the baby responds vigorously to the color red

Every day when Jessica returns home from work, her daughter gives her a big hug as soon as she walks through the front door. Now, the sight of the front door makes Jessica feel happy. In this example, the conditioned stimulus is:

The front door

When considering the Rescorla-Wagner model it is true that :

The predictions made by the model should be able to be tested and provide new data

____ does not require the cerebellum in a classical conditioning experiment

The unconditioned response

Suppose that the gill-withdrawal reflex is habituated in Aplysia by repeatedly touching the siphon. If the habituation is homosynaptic, what would occur?

Touching the tail will cause a gill-withdrawal response

The Rescorla-Wagner model explains conditioning as modulation of the effectiveness of the ____ for learning, while the Mackintosh model explains conditioning through modulation of attention to the ____ .

US; CS

The conditioned compensatory response occurs in response to the ____ in order to prepare the organism for the ____

US;CR

If someone blows a puff of air into one's eyes, the person automatically blinks. In this example, the puff of air is a(n):

Unconditioned stimulus

the most difficult stimulus to habituate to would be what?

the loud, banging sound that occurs every 5 minutes

In Aplysia, what accounts for the habituation of the gill-withdrawal reflex?

a decrease in the amount of glutamate released by the sensory neuron

Cortical neurons that re physically close together are tuned to similar stimulus features. This is known as:

a topographic map

____ is a neurotransmitter that has many functions in the brain, including the promotion of neural plasticity

acetylcholine

Dylan and Aaron both enjoy foreign films. If a person later learns that Dylan also enjoys riding dirt bikes, the person may infer that Aaron also enjoys riding dirt bikes. This is an example of:

acquired equivalence

positive reinforcement involves ____ an outcome to ____ a behavior

adding; increase

The study of how organisms allocate their time and resources among possible options is known as:

behavioral economics

Suppose one pairs a light and a tone in the first phase of a sensory preconditioning paradigm. If one then pairs just the light with a food pellet, such that the light elicits a salivation response, the tone presented alone will:

also elicit salivation

Parents who decide to use punishment on a misbehaving child should:

also reinforce good behavior

Damage to the basal forebrain can cause what type of disorder?

anterograde amnesia

patients with damage to the cerebellum:

are slower in learning a CR

Discriminative stimuli

are: stimuli that signal whether a particular response will lead to a particular outcome

when the US is an unpleasant event such as shock, the conditioning is called ____ conditioning.

aversive

The distancing approach to fighting an addiction involves:

avoiding the stimulus that triggers the unwanted response

Neurons in the sensory cortices can:

be retuned in adults

James' grades are dropping, and he has isolated himself in his room and doesn't have any interactions with individuals. His only focus is playing his game. As punishment for his grades dropping, he is grounded from any games. His parents have caught him trying to play at night, and he has even tried to go to his neighbors to do so. What type of addiction is James exhibiting?

behavioral

The process by which websites use a form of generalization to predict what one would buy is called:

collaborative filtering

a psychological representation of a category of objects, events, or people in the world is referred to as a:

concept

The process by which one learns about new categories usually based on common features is known as:

concept formation

Dionne competes on her high school's track team. She always feels naturally nervous right before a race. She also notices that on days when she is not racing, just seeing the track still made her feel nervous. Her nervousness at seeing the track on non-race days is a(n):

conditioned response

The conditioned stimulus elicits the:

conditioned response

____ is a tendency to ignore information that conflicts with prior belief and focus on information that is consistent with that belief.

confirmation bias

A set of stimuli in the world that share the same consequence as the stimulus whose consequence is already known is referred to as:

consequential region

A child is given a gold star every time they get an "A" on a test. This is an example of:

continuous reinforcement

The capacity for cortical receptive fields and cortical spatial organization to change as a result of experience is called:

cortical pasticity

If a loud noise is presented repeatedly to a rat, the rat's acoustic startle reflex will:

decrease

Suppose a rat has been conditioned by presenting a loud buzzing sound followed by a shock. According to the Rescorla-Wagner model, if one then presents several trials of the buzzing sound alone, without any shock, the association between the buzzing sound and the shock will ____

decrease

Andrea is trying to stop biting her nails. whenever she gets the urge to bite her nails, she forces herself to count to 100 before giving into her urge. This is an example of:

delayed reinforcement

James doesn't mind the smell of gas since he has worked at the gas station for 15 years. This is an example of:

desensitization

Larry is visiting his grandmother and cooking dinner for her. Since his grandmother has a different model microwave over than his, he has learned that he needs to pus a different sequence of buttons on his grandmother's microwave oven when he wants to use it for cooking. this is an example of:

discrimination

In a ____ representation, stimuli are represented by overlapping sets of nodes or stimulus elements

distributed

The discrete-component model and the distributed model differ in that only the:

distributed model includes an internal representation layer

If one is feeling bored with one's romantic partner, which approach would be expected to improve one's feelings by bringing about dishabituation?

doing something new and exciting together

What neurotransmitter is damaged in individuals suffering from Parkinson's disease?

dopamine

Why is dopamine believed to be involved in reinforcement?

dopamine release is triggered by primary and secondary reinforcers

It has been suggested that drug addicts should use small amounts of their drug during therapy to extinguish their habit. This is because:

drug use is part of the context

Activity in the inferior olive is high at the start of training and diminishes with successive trials is evidence of what mechanism in the brain?

error-correction mechanism

A training procedure in which difficult discrimination is learned by starting with an easy version of the task and proceeding to incrementally harder versions as the easier ones are mastered is referred to as ____ learning.

error-less discrimination

The shape of generalization gradients shows that two very similar stimuli are ____, while two very different stimuli are ____.

expected to produce similar consequences; expected to produce different consequences

Suppose one's roommate has gotten into a bad habit of talking whenever the roommate is trying to study. The roommate decides to ignore this habit. This is an example of:

extinction

When two cues compete to predict a US or other outcome, the one that is most strongly learned is usually the cue that is learned ____ as revealed in studies of blocking.

first

Jessie is lying down when suddenly a firefly moves across her room. It disappears after 10 seconds. When reappears, she stares at it again. The duration of time in which she looks at it is known as:

fixation time

In rats, dopamine is released from the VTA/SNc is triggered by encounters with:

food, sex, secondary

Lesion studies suggest that the interpositus nucleus is involved in ____, while the cerebellar cortex is involved in ____

formation and execution of the CR; response timing

When researchers gave animals an injection of an inert placebo to pre-expose then to the contextual cues associated with drug use, they found that the animals:

formed an association between the context and drug use more slowly than normal

According to the idea of latent inhibition, pre-exposing a rat to a light by itself will make it:

harder for the rat to learn to associate light with food

The hippocampus and associated brain regions, including the entorhinal cortex and dentate gyrus, are known as the:

hippocampal region

The tendency of the body to gravitate toward a state of equilibrium or balance is known as:

homeostasis

Hedonic value refers to ____, while motivational value refers to ____.

how much one likes a reinforcer; how much one wants a reinforcer

Studies involving repeated presentation of two simultaneous touches on the finger have shown that the ability to discriminate the positions of the two touches ____

improves

Increasing dopamine appears to:

increase how much one wants something but not how much one likes it

Cocaine and amhetamine work by:

increasing the levels of dopamine

If one trains a discrete-component model to respond to a bluw light, how will it respond to a blue-green light?

it will not respond at all to the blue-green light

Suppose a person lesions the hippocampus of a rabbit. The person presents a blue light and a yellow light together for several trials, and then presents just the yellow light followed by a shock until the rabbit is startled by the yellow light alone. How will the lesioned rabbit respond if the person now presents just the blue light?

it will not startle to the blue light at all

A reduction in learning about a CS to which there has been prior exposure without any US is called ____

latent inhibition

Suppose a person never buys eggs because they don't like them One weekend, they have guests who love eggs, and so they decide to buy some at the store. Even though they have never bought eggs at the store, they know exactly where they are from all the times that they have been there. the that they they learned where the eggs are during those past trips is an example of:

latent learning

cochlear implants:

lead to reorganization of the auditory cortex in cats

the Conditioned Emotional Response was a technique developed to study:

learned fear

According to the text, the compound exposure in phase 1 establishes an association between the tone and light. In phase 2 the light becomes associated with the air puff, and this learning is directly transferred to the tone too. This is referred to as:

meaning-based generalization

The medial surface of the temporal lobe that contains the hippocampus, the amygdala, and other structures important for memory is referred to as the:

medial temporal lobe

Which item is an example of a secondary reinforcer?

money

In a word-stem completion task, people are:

more likely to fill in the blanks to form words that they have previously seen

After working $15 an hour, Sally's pay was cut to $8 an hour. She stopped working so hard, working much less than her coworkers, who had been earning $8 an hour all along. this is an example of:

negative contrast

Aiden plays well with his brother and with his sister, but when Aiden tries to play with both of them together the three of them just end up arguing. This is an example of:

negative patterning

suppose a man had his drivers license revoked due to several unpaid traffic tickets. the taking away of his license would be ____ of the mans behavior of not paying tickets.

negative punishment

Suppose a child whines continuously until his parents give him a cookie. The cessation of the child's whining would be ____ of the parents behavior of giving the cookie.

negative reinforcement

Drug addicts continue taking drugs in part to avoid the unpleasant effects of withdrawal. in this case, the behavior of taking drugs is being:

negatively reinforced

In Aplysia, the:

neural connections involved in the gill-withdrawal reflex have been well mapped out

If one lesions the primary auditory cortex of a cat, the cat will:

not be able to discriminate between different tones

Familiarity can be defined as:

perception of similarity that occurs from an event of repitition

The behavior of rats navigating three-arm mazes before and after the mazes are rotated demonstrates that:

place cell responses are based on visual cues in the enviornment

the ability of rats to learn spatial layout declines when:

place fields are prevented from shrinking

Interfering with dopamine seems to:

reduce motivation to perform a behavior but have no effect on the enjoyment of a reinforcer

While driving to work one day, Jennifer heard her favorite song on the radio. Soon after the song started playing, she was rear-ended by another car. Now, her favorite song causes her to feel nervous and tense. If she wishes to use extinction to stop these unpleasant feelings form occurring when her favorite song comes on, she should:

play her favorite song whenever she drives anywhere without getting in an accident

In order to get Pavlov's dog to experience extinction, one would:

play the tone repeatedly without any food

Children may misbehave in order to get the attention that is associated with being punished. In this example, the attention serves as ____ for misbehavior

positive reinforcement

The ____ has/have different subregions for each kind of sensory stimulation

poutine cortex

For humans performing a category-learning task, Gluck and Bower's neural network model can:

predict how often a particular categorization will be made

The central tendency of an idealized version of a concept or category is referred to as the:

prototype

The process of providing consequences for a behavior that decreases the probability of that behavior is called:

punishment

The main difference between reinforcement and punishment is that:

punishment decreases a behavior, while reinforcement increases a behavior

Error-less discrimination learning does have some significant drawbacks. While it produces ____ and ____ learning of discriminations, later studies have shown that it is rigid and inflexible

rapid; strong

Touching a patch of skin on the hand causes a particular neuron in the brain to fire. That particular patch of skin would be a part of the neuron's:

receptive field

Rats with hippocampal damage are impaired in the ability to:

recognize objects if the context and position of the objects are integrated

If a person wants to use shaping to train a new puppy to respond to a name, he would call the name and then:

reward when the puppy looks at him, then for turning toward him and then for taking a few steps in his direction

In studies of rats learning to find their way through a maze, Tolman and Honzik found that rats that were:

rewarded every day learned the maze as well as rats who started receiving rewards on day 11

Suppose one conditions a dog to salivate in response to a tone (by pairing the tone with food). Then, the person presents both the tone and a light together, followed by food. The dog will:

salivate only in response to the tone

Freda once became sick after eating pepperoni pizza. Based on the idea of generalization gradient, which food would she be most likely to avoid in the future?

sausage pizza

behavioral addictions:

seem to activate the same reinforcement system in the brain as drug addictions do

Gluck and Myers proposed a model of the hippocampal region which the hippocampus:

selects what information enters the memory and how it is to be encoded

According to the dual process theory, when stimuli are highly arousing:

sensitization processes determine the response

Gavin often gets punched by Tyler, the school bully. Gavin is also afraid of Tyler's Twin brother, Tristan, since Tristan looks like Tyler. This is an example of:

similarity-based generalization

Which characteristic is seen in people with schizophrenia?

smaller volume of the hippocampus

Robert Post found that, after an initial stressful event triggered a disorder such as depression, increasingly minor stressful event trigger additional buts of depression. This reasoning indicates that:

some individuals become sensitized to stress and its associated physiological states

A man would be considered to have a pathological addiction to alcohol if he:

suffers from a medical condition caused by his alcohol use

In the Rescorla-Wagner model, the expectation of the US is described by the:

sum of the association weights of all the cues in a trial

If one blocks dopamine in an amphetamine user, one would expect that it would:

suppress cravings for the drug

Sensitization is demonstrated in Aplysia when, after shocking the ____, touching the siphon causes a ____ gill-withdrawal reflex

tail; strengthened

Classical conditioning involves learning:

that one stimulus predicts an important events

The phenomenon of blocking demonstrates that:

the CS must provide non-redundant information

Neophobia refers to:

the act of actively avoiding a novel object

For punishment to be most effective:

the behavior cannot be concurrently reinforced

In the case of Thorndike's cats learning to escape from a puzzle box, the stimulus (S) was ____ and the response (R) was ____

the box; their movements that open the door

A conditioned eye blink response can be produced by stimulating:

the inferior olive as the US

What part of the brain is responsible for making an individual feel bad for not being picked to play in the basketball game?

the insular cortex

In Garcia and Koeliling's taste aversion studies, it was found that rats in:

the poison group were more likely to associate a taste with their illness than a tone with their illness

Which region in the brain contains the dopamine-producing neurons that project to the frontal cortex?

the ventral temental area

Awarding children points for good behavior which they can exchange at the end of the day for small toys, is an example of what?

token economy

With repeated administration of a drug, an organism will require larger and larger doses of the drug in order to achieve the same effect. This is known as:

tolerance

Consider a blocking experiment in which an animal is first conditioned to associate a light with shock and then is presented with a tone and light together followed by a shock. According to CS modulation theories such as that of Mackintosh, blocking would occur because the:

tone is ignored

In a ____ representation, nodes or neurons responding to physically similar stimuli are near each other.

topographic

If sensitization of the gill-withdrawal reflex is heterosynaptic, what would occur?

touching the mantle will cause a gill-withdrawal response

Chaining involves ____, whereas shaping involves ____

training individual components of a complex response; reinforcing successive approximations to a desired behavior

A theory of learning in which all of the cues that occur during a trial and all of the changes that result is considered a single event is known as:

trial-level model

Electrical stimulation of the ____ is reinforcing to rats.

ventral tegmental area

In humans, through the use of PET and f/MRI, increased activity can be seen in dopamine target sites such as the striatum. what triggers this activity?

video games and cocaine

Research on addiction to a romantic love has shown that:

viewing pictures of a romantic partner can activate reward centers in the brain

If the visual input to the cortex is cut off during development:

visual acuity may be permanently degraded if sight is later restored

According to the Premack Principle, if a child would rather wash dishes than do homework:

washing dishes could be used as a reward for doing homework

which item is an example of a primary reinforcer?

water

A stroke is:

when blood flow to a region of the brain stops