Incentive Salience Hypothesis

Chapter 5: Operant Conditioning

People and other animals learn to learn to obtain or refrain from certain responses to obtain rewards or avoid negative consequences. Consequently, these conditions are created in the brain by the dorsal striatum and the orbitofrontal cortex. Dorsal striatum is particularly crucial in learning involving discriminative stimuli. Consequently, the damage to the striatum disrupts the ability to correctly respond to the discriminative stimulus. The dorsal striatum is associated with discriminative stimuli (S) and Response (R) since it involves feedback on the enforcement and punishment. Orbitofrontal cortex on the other hand plays a crucial role in the prediction of outcome (O). Consequently, the lesion impairs the dorsal striatum.  Impaired dorsal striatum have a negative effect on the correct response to the discriminate stimuli (Gluck, Mercado, " Myers, 2014). It is important to note orbitofrontal cortex can integrate many types of information including visceral sensation such as thirst, hunger, and also sensory modalities such as sight, light, and touch. During the S-R-O flow of information, S-R information is automatically processed by the dorsal striatum which then sends the information to the orbitofrontal cortex for appropriate response.

Wanting and liking are two words that are often believed to denote the same meaning. However, wanting is attached to motivational value; people are willing to go extra mile to obtain them. On the other hand, a like enforcer is not enough to motivate people to work towards obtaining them compared to what they want. In wanting, dopamine neurotransmitter produced by the neurons in the brain are used to transmit the information.  Notably, the stimulation of ventral tegmental area (VTA) lead to high production of dopamine which leads to increases the wanting (Gluck, Mercado, " Myers, 2014).  Consequently, when the neurotransmitter is blocked from having an action in the brain, the individual loses ability to like the pleasurable stimuli.  These individuals lose the will to work for what they want. The substantia nigra secretion of the dopamine helps in the movement of the dopamine in the striatum.

Incentive salience hypothesis is the hypothesis that the role of dopamine in the operant conditioning is to help in signaling how much an animal want a particular outcome. Consequently, how much they want that outcome will motivate them to work for it. Accordingly, the incentive resilient such as food motivates animals to work for it and those animals with less dopamine lack the motivation to work for what they want. Notably, high level of dopamine increases craving and people would do extra duties to obtain what they want. The wanting effect is greatly reduced when the level of dopamine falls with no effect on the liking (Gluck, Mercado, " Myers, 2014). However, the individual with low dopamine suffers from reduced motivation with regard to the enforcers. Consequently, dopamine  is increased by the exposure to the reinforcement or desirable items.

Emotional and physical pain activates and follow multiple pathways within the brain system. Somatosensory cortex encodes the intensity as well as the physical location of the pain the body, however, it does not encode how the pain really feels. The insula plays a crucial role in conscious awareness of the physical and emotional states of the body. It can help in the perception of pain and negative emotions attached such as hunger, disgust, and rejection (Gluck, Mercado, " Myers, 2014). Opioid system in the brain, which is responsible for the liking, coordinates with the insula to determine the degree of the pain that causes the disliking. When there is a damage to the insula, people cannot learn to avoid the unpleasant outcomes.  The dorsal anterior cingulate cortex then tell an individual what to do with the pain. It detect the severity of an event and suggest on the appropriate response to them. The dopamine system sends the signal to the brain so that the negative reinforcers can be avoided or reduced.

Individuals suffering from pathological addition experience both positive and negative reinforcement, which are the forces working against them. A positive reinforcement is experienced by the high and the pleasure received from it, while negative reinforcement is the withdrawal effect. Cocaine and the amphetamines work by increasing the dopamine level in the brain, consequently, the individual feels that they really want the drug, thus causing addiction. It is important to note that during the early stages of addiction, liking is at the center while over a long period of usage, the individual feels that they can do extra duties to obtain the drugs. Behavioral addiction such as gambling also affect the brain reinforcement system leading to addiction. The behavioral addiction reflect the dysfunction in the brain system that is responsible for drug addiction (Gluck, Mercado, " Myers, 2014). Those who gamble crave for rewards. This problem is created by the high rate of the dopamine in the brain same as those suffering from drug addiction.

Naltrexone helps in the addiction problem by blocking the opiate receptors leading to hedonic reduction. However, this treatment does not reduce the wanting effect of drugs and gambling which makes it less effective. However, extinction minimizes the effect of the conditioned association which leads to decline in the wanting. Distancing involves the avoidance of the stimuli that can trigger negative response. Distance mechanisms targets the S element since the absence of S can never trigger a response (R). On the other hand, differential reinforcement of alternative behaviors finding ways to adopt alternative behaviors such as favorite sport and places (Gluck, Mercado, " Myers, 2014). This mechanism targets the outcome of a particular reinforcement. Delayed reinforcement increases the time between response and outcome. Consequently, increasing delays weakens the craving, thus targeting both the response and the outcome.

Chapter 6: Generalization, Discrimination Learning, and Concept Formation

Generalization is the application of past learning concepts to solve emerging situations and problems while discrimination on the other hand involves the application different strategies to solve different problems.  Humans face various challenges in their daily lives and their ability to come out of these challenges successfully depends on how they are able to recognize similarity between events, categorize these events, and form generalized and discriminate concepts of solving these challenges. Discrimination training which involves exposing the participants to more than one stimuli in a trial (Gluck, Mercado, " Myers, 2014). The overlap in the stimuli representation narrows the generalization gradient. In the discrimination learning, individuals are exposed to different mixtures of stimuli.  Consequently, people who receive discrimination endorse ambiguous strategies for making broader generalization. Learned specificity on the other hand is achieved when   learning session include movement condition and an environment  same as the one required during the performance of the specific. Learning becomes difficult when complex concepts are integrated into the learning process. However, removing the already practiced and performed knowledge does not affect the performance of the remaining task.

Discrimination training can lead to lead to a shift in the generalization gradient since humans tend to shift away from nonreinforced stimuli. When stimuli vary along physical continuum such as sound, color, tone, and others, people tend to shift their interest to what they like the most. The peak shift represent both the positive and inhibitory stimulus centered around S+ and S-. Notably, the peak shift moves from the area of maximal responding to positive stimuli leading to a shift in the generalization gradient. Negative patterning is a situation where the combination of known cues have radically different meaning from their individual component. This situation is challenging, as the individual must rely on multiple cues for correct interpretation. The response to individual cue is positive while a combination of cues yields a negative response. However, with training, both humans and other animals can master the negative patterning to produce the correct response. In addition, configural node that detect the combination of two or more cues can be used to solve this problem. Activation of the configural node cancels out the effects of a single stimulus such as light or tone only. An individual can then respond to either cues alone, in addition, he can equally interpreted the combined cues to cancel the effect of the negative patterning (Gluck, Mercado, " Myers, 2014).

Sensory preconditioning test on how the co-occurrence of two or more stimuli can lead to generalization by a way of training. It is usually done in three phases with the first involving animals in a controlled group are exposed to a combination of two stimuli. In phase two, the animals learn that an individual stimulus by itself can predict an important outcome (Gluck, Mercado, " Myers, 2014). In step three, the animals are exposed to one stimulus only. Sensory preconditioning indicates that the co-occurrence of stimuli produce is enough to produce meaning generalization from another stimulus. Sensory preconditioning differs from blocking in that the latter is based on the premise that conditioning only occurs when a stimulus is both useful and non-redundantly predict the future events.

Acquired equivalence occurs when the occurrence of dissimilar stimuli produce the same outcome. The fact that two stimuli produce same outcome increased the generalization even when they were not similar. Notably, the procedure is done by exposing pigeons to light that change between different colors (Gluck, Mercado, " Myers, 2014). Since the birds had learned the outcome of phase one, they were able to obtain equivalent result in the other phases. Acquired equivalence is a form of generalization since people can relate the outcome of events even when such events are dissimilar but share the same history.

Category learning is the process through which humans and animals learn to classify various cues onto category. It involves exposing people to set of visual cues consisting of abstract geometrical elements. Prototype on the other hand is the categorization of animals based on their family resemblance and other features shared by most individuals in a given category .prototype enables inductive inferences because of the high degree of the resemblance among the members of a family. We can thus, categorize animals based on the features they share in common (Gluck, Mercado, " Myers, 2014). However, this inference is made only on the basis of probability and are not necessarily true. Based on the inductive inferences, individuals can decide on how to respond to various stimuli.

Neuron receptive fields plays crucial role by allowing some degree of generalization. The brain is organized to resemble the shared elements that activate common neurons and learning is likely to be generalized. Notably the cortical neurons display the receptive field which allows for the generalization. Hippocampal region of the brain is involved in associative learning and conditioning learning (Gluck, Mercado, " Myers, 2014). Consequently, hippocampus is necessary for the generalization of various stimuli and the rational memory. This region is involved in the development of new concepts. It is important to note that damage to hippocampal region leads to no sensory preconditioning thus, affecting the generalization.

Consequently, the dysfunction of the hippocampal region have a negative effect on the generalization and learning. Schizophrenia disorder affect how their patients generalize and perceive the world around them. This condition is associated with severed mental disorder symptoms including hallucination, flattered effects, delusion, and social impairment (Gluck, Mercado, " Myers, 2014). Notably, the disease  is associated with the abnormalities of the hippocampus. They are thus, not able to apply the simple concepts that they have learned in new concepts. The hippocampus also plays a significant role in the acquisition of the acquired equivalent learning. Notably, the damage to the hippocampal region of the brain negatively affect acquired equivalent learning.

Stereotype is evident when a person categorizes another based on their race, gender, ethnicity, religion, age, tradition, among others (Gluck, Mercado, " Myers, 2014). Moreover, they use these factors for their generalization that may not reflect a true picture of the individual person. This specificity leads an individual to develop the stereotyping behavior. Stereotype can be useful in that it can build a sense of belonging by viewing our own category  as better placed to deal with certain issues compared to other groups. However, stereotype is also a social evil that can be used to undermine other groups that do not belong to a certain category.

Chapter 7: Episodic and Semantic memory

Memory is the process by which humans and other animals maintain information over time by drawing their experiences in order to use the information in new situation. Learning takes place when new information is acquired. Notably, memory forms an essential part of human live, and without the memory of the past, people cannot operate in the present or think about the future. Memory covers three information processing aspects; encoding, storage, and retrieval. Information from the sensory input is changed into a form that human system cope with and for easy storage.  The information can be encoded visually, acoustically, or semantically. However, the information in long term memory uses semantic coding. The storage of information depends on a number of factors including where the information is stored and the duration the memory can last. Notably, the way people store information have an effect on the way it is retrieved (Gluck, Mercado, " Myers, 2014). The encoded information can be stored in short term and long term memory depending on the type of information. Memory retrieval basically is getting the information out of storage to be used in the present. If somebody cannot remember a piece of information, then it means he cannot retrieve it. Retrieving of information can be sequential or through association.  By organizing the information in sequence or being exposed to the information over time, one can retrieve the stored information.

H.M suffered from a severe epileptic seizure making the neurons of his brain to fire wildly and uncontrollably.  Finally, the patient and his family agreed on brain surgery to reduce the effects of the disease. The brain surgery involved the removal of the medial temporal lobes laterally since his condition was so severe.  The surgery was successful in reducing the effects of the epilepsy but the patient developed amnesia (Gluck, Mercado, " Myers, 2014). His condition mostly affected his short term memory as he could not remember the information he has just received. However, he knew his own poor condition. The brain surgery increased the patient’s IQ and he could concentrate on what he was doing. Consequently, H.M lost both the declarative and declarative memory.

Declarative memory includes both the semantic and the episodic memory; an individual can easily declare or communicate the knowledge gained the declarative memory. Example of declarative memory is the winner of the 2018 FIFA world cup and the first president of the US. Non-declarative memory on the other hand include skills that cannot be easily communicated verbally. Such include playing games. Explicit memory consist of the semantic and episodic memory that a person is aware of (Gluck, Mercado, " Myers, 2014). It is based on the premise that you know that you such facts. It can include the year of birth or your high school graduation year. Implicit memory is the memory that you have acquired without knowing. Episodic memory is the memory for special events and life situations. Such may include your wedding details and giving birth for the first time. Semantic memory on the other hand are memories for personal information, facts, and the general knowledge of things happening around us.  Such memory include your name and year of birth.

Long-term memory can last for many years and with little cues, and individual can recall events that happened many years back. In a study where individuals were asked to recall the names of their high school classmates, it was evident that those who graduated earlier could hardly recall all the names compared to the recent graduates. However, when they were given some cues, most of the earlier and recent graduates could remember the names of their high schoolmates.

Assessing semantic memory in animals is not as easy as that in humans. However, many studies such as the radial arm maze has been used to show that animals too have semantic memory while King gorilla research tested episodic memory in animal. In addition, other experiments with birds, rats, dolphins have also been done to assess these types of memory in animals.

Consequently, one can enhance encoding when he can relate the acquired information to past events and experiences. If for example, one has a background about a particular topic, he can easily relate new concepts on the same topic. In addition, deep analysis of information can enhance one’s encoding. Deep analysis involves deep consideration of facts and thinking about the subject by practicing (Gluck, Mercado, " Myers, 2014). One can also enhance encoding by making it a habit to think about major points relating to the topic. In addition, when the available cues are similar to the ones during the encoding, one is likely to encode the information.

Recall is to test how much information an individual has encoded in his memory. In a cued recall, one is given some aid to enable them recall past events. Such can include first or last letters of an item or a place. Recognition involves picking the correct answer from available choices. In recognition, the correct answer to a particular question is mixed up with other incorrect answer and an individual is expected to recall by picking out the correct answer.

In some situation, event and episodic memory may fail and when such failure occurs, one can forget the information when it is demanded. Forgetting is a passive process through which individuals forget old memories especially when such information is rarely accessed. Interference occurs when two or more memories overlap, thus, reducing the strength of one or all the memories (Gluck, Mercado, " Myers, 2014). Interference can be proactive which means that new learning is disrupted by already known old information. Retroactive interference on the other hand is a case where new learning disrupt old information. False memory is the creation of memories of events that never happened.

Memory consolidation is a time period in which the semantic and episodic memory are vulnerable and one can easily loose them. Ribot law states that recent memories are likely to be lost compared to older memories during incidents of retrograde amnesia. In this regard, when a patient with severe depression receives  electroconvulsive therapy, they are likely to suffer impairment of recent memories compared to older distant memories (Gluck, Mercado, " Myers, 2014).

Chapter 8: Eichenbaum Chapter

The brain has a complex part of the body with distinct types of memory that control place and response learning.  However, the brain memory types are distinguished by the brain pathways that support them and their performance characteristics (Eichenbaum, 2012).  Place learning is the initial learning mediated by the hippocampus while response learning is developed over time and it is mediated by the caudate nucleus. Notably, place and response learning can be tested in a T-shaped maze by placing the rats in a T-shaped maze and training the rats on where to turn to get reward (food). Over a short time, place strategy dominates while response strategy dominates after a significant period of training. In this regard, the behavior is an example of response learning.

Packard and McGaugh also did the T-Shaped maze testing. After eight days of training the rats, they found that place presentation dominated the normal rats as they were always present in the place where they previous had found food. However, with other days of training, they discovered that the rats started adopting the response strategy. From Packard and McGaugh’s experiment, it can be concluded that different brain systems support different types of representation and a damage to a particular brain system can affect the learning process (Eichenbaum, 2012). At the initial stages, animal develop place representation which is mediated by the hippocampus, however, when they are exposed to vigorous training, they develop a response mechanism.

In their experiment, McDonald and White found that the hippocampus, the amygdala, and the dorsal striatum play a significant role in the learning process. Hippocampus is responsible for acquiring information that relates to relationship among cues and events. Amygdala on the other hand mediate acquisition of behavior based on events since the damage to the amygdala affects the conditioned emotional preference. Consequently, damage dorsal striatum have a negative effect on the habit or response learning since it is mediates stimuli and response. In their experiment, a win-shift rule demand memory for every particular daily activities. Win-stay on the other hand involves placing food reward on any particular lit arm, in which the animal could approach and get their reward each time. Win-stay minimizes the presence of spatial cues and emphases approach to specific cues. Conditioned place preference emphasizes a strong association between reward and absence of reward defined by non-spatial cues (Eichenbaum, 2012).

Parkinson is a condition that affects the central nervous system and it can affect movement. Severe Parkinson condition reduces caudate uptake thus, reducing the ability of the individual to recall performance. Striatal damage reduces habit learning leading to Parkinson condition. Notably, habit learning and declarative memory was tested using the weather prediction game. This experiment involved the patients with degenerated neuron condition of the brain and the amnestic patient. These patients are required to predict the probability of sunshine and or rain outcome (Eichenbaum, 2012). The patients are represented with one to three cards with each card associated with either sunshine or rain outcome. However, some cards have conjoint probabilities. This experiment tests the caudal memory which is responsible for habit learning.  The study found that declarative learning was impaired by amnesia while habit learning was impaired by the striatal damage.

The weather prediction game found that the Parkinson suffered from striatal damage that impairs habit learning. They show deficiency in the ability to associate the discriminative stimulus with appropriate response.  On the other hand, amnestic patients suffered from the impairment of the  declarative memory. The data from this experiment shows that the medial temporal lobe is plays a crucial role in the habit learning while striatum controls the declarative memory. Consequently, this data support the evidence that one can learn without knowing since the damage to a particular type of brain does not directly affect learning controlled by other types of the brain system.

Benchere and his colleagues also carried out an experiment to determine the influence of various parts of the brain on learning. Their patients had selective damage to amygdala and the hippocampus. One of the patients had Urbach-Wiethe diseases, which is associated with the calcification of the amygdala tissue adjacent to hippocampus. Another patient had experienced multiple cardiac arrest, transient hypoxia, and ischemia, which led to damage of amygdala. A third patient suffered from herpes simplex leading to damage to both the amygdala and the hippocampus. Conditioned stimuli was the simple colored slide, neural stimuli was the loud sound that produced automatic nervous system response, condition stimuli was a pure tone, unconditioned stimulus was the loud boat horn (Eichenbaum, 2012). Involuntary response included sweating. Notably, declarative memory was tested using the patient with the hippocampal damage who showed normal responsiveness to conditioned stimuli.

The studies of this chapter demonstrate the respective roles of the amygdala, hippocampus, and dorsal striatum in learning and memory. Consequently, one can learn without being aware of it due to the fact that the brain can operate in parallel. Notably, the brain can acquire different kinds of information with independent neural systems making it possible for the brain to operate in parallel. Damage of the hippocampus can only impair the win-shift task and not the win-stay task or the conditioned cue preference (Eichenbaum, 2012).   This would mean that the brain neuron system could work independently.

References

Top of Form

Bottom of Form

Eichenbaum, H. (2012). The cognitive neuroscience of memory: An introduction. New York: Oxford University Press.

Gluck, M. A., Mercado, E., " Myers, C. E. (2014). Learning and memory: From brain to behavior. New York: Worth Publishers.