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Brain and General Sections

Brain and General Sections



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Whereabouts in the brain gets triggered/switched on when an addictive substance is ingested/taken. I'm doing an addiction study with a couple of colleagues and would like some help with it.


It depends on the type of addictive substances (i.e., opioid, amphetamine, LSD, etc). Different types bind to different sets of receptors of neurotransmitters (i.e., dopamine, serotonin, GABA, etc.) in the nervous system. And different receptors have different distribution in the nervous system. So the affected regions are different for different addictive substances.

The easy-to-read, entry-level references that you can use are probably How Drugs Affect the Brain and Central Nervous System and Drugs and the Brain. For in-depth references, you can search for the literature on each specific drug at NCBI.


Whereabouts in the brain gets triggered/switched on when an addictive substance is ingested/taken.

Irrespective of their particular pharmacology, the one thing that all drugs of addiction have in common is that they will all converge onto a single common neural substrate, the mesolimbic dopamine pathway.

The mesolimbic pathway has dopamineric projections from the ventral tegmental area (VTA) to the nucleus accumbens.

There are other projections from the VTA to the frontal lobe, but the mesolimbic pathway is between VTA and nucleus accumbens.

This pathway is also called the "reward pathway" of the brain and is why dopamine is commonly associated with "pleasure". However, thinking about things this way is very misleading because it's thought that the mesolimbic pathway has less to do with pleasure or reward, and more to do with the salience of stimuli e.g. food or sex.

The involvement of this common pathway in all drugs of addiction has influenced the thinking of addiction as a disorder of incentive salience.

Briefly, administration of a drug of addiction will activate the mesolimbic pathway, imbuing the drug and any associated cues, with salience. With repeated exposure to the drug, a peculiar phenomenon will occur. Even though the user might subjectively report tolerance to the drug, there will be greater activation of the mesolimbic pathway than the first time they had taken the drug. The process of increased responsiveness to the same drug dose after repeated dosing is referred to as receptor sensitisation and may reflect the process by which use of a drug transitions to addiction.

The Incentive Sensitization Theory of Addiction was proposed in 1993:

The neural basis of drug craving: An incentive-sensitization theory of addiction

This paper presents a biopsychological theory of drug addiction, the 'Incentive-Sensitization Theory'. The theory addresses three fundamental questions. The first is: why do addicts crave drugs? That is, what is the psychological and neurobiological basis of drug craving? The second is: why does drug craving persist even after long periods of abstinence? The third is whether 'wanting' drugs (drug craving) is attributable to 'liking' drugs (to the subjective pleasurable effects of drugs)? The theory posits the following.

(1) Addictive drugs share the ability to enhance mesotelencephalic dopamine neurotransmission.

(2) One psychological function of this neural system is to attribute 'incentive salience' to the perception and mental representation of events associated with activation of the system. Incentive salience is a psychological process that transforms the perception of stimuli, imbuing them with salience, making them attractive, 'wanted', incentive stimuli.

(3) In some individuals the repeated use of addictive drugs produces incremental neuroadaptations in this neural system, rendering it increasingly and perhaps permanently, hypersensitive ('sensitized') to drugs and drug-associated stimuli. The sensitization of dopamine systems is gated by associative learning, which causes excessive incentive salience to be attributed to the act of drug taking and to stimuli associated with drug taking. It is specifically the sensitization of incentive salience, therefore, that transforms ordinary 'wanting' into excessive drug craving.

(4) It is further proposed that sensitization of the neural systems responsible for incentive salience (for 'wanting') can occur independently of changes in neural systems that mediate the subjective pleasurable effects of drugs (drug 'liking') and of neural systems that mediate withdrawal. Thus, sensitization of incentive salience can produce addictive behavior (compulsive drug seeking and drug taking) even if the expectation of drug pleasure or the aversive properties of withdrawal are diminished and even in the face of strong disincentives, including the loss of reputation, job, home and family. We review evidence for this view of addiction and discuss its implications for understanding the psychology and neurobiology of addiction.


Further Study

These optional resources are provided for students that wish to explore this topic more fully.

Course optional resources.
TYPE CONTENT CONTEXT
Animation MIT Perceptual Science Group. Lightness Perception and Lightness Illusions. More from this source used in the lecture video: eleven animations based on a paper by Edward H. Adelson.
Animation Bach, Michael. 92 Visual Phenomena & Optical Illusions. More from this source used in the lecture video: animations of optical illusions.
Videos Visual illusion experiments by Prof. Richard Gregory More from this source used in the lecture video: includes the rotating Charlie Chaplin mask illusion.
Web resource History of Psychology: Contemporary Foundations. Discovering Psychology. WGBH Educational Foundation, 2001. Timeline of key events, publications and perspectives in the development of psychology, from late 19th century to the present.
Textbook supplement Study materials for Ch. 1, "Psychology: Yesterday and Today." In Kosslyn & Rosenberg, Psychology in Context, 3/e (Pearson, 2007) Practice test questions, flashcards, and media for a related textbook.

Modern psychology grew out of medical explorations of the brain and one of the first psychology textbooks was called 'Principles of Physiological Psychology'.

In addition to the common principle of generalization, physiologists make significant use of the principle of reduction, seeking the simplest explanation for complex phenomena (perhaps in contrast with a more detailed description that a physicist may use).

Much early knowledge was gained through observing how behavior changes when different parts of the brain are damaged. Animal experiments, always controversial, have also been used, for example by removing or cutting various parts of the brain and observing differences in behavior.

Utilizing necessary brain surgery has also been useful, including prodding parts of the brain and asking the conscious patient what they experience (there are no nerve endings in the brain so the patient feels no pain).

Study of brain chemistry have included the exploration of how various drugs affect brain functioning.

Modern scanning systems, such as fMRI and PET have given further insights as activation of parts of the brain can be seen without the more intrusive former methods.

Physiological psychology covers the general area of 'brain and behavior' that is a modular subject in many university courses.


Women And Objectification: Brain Sees Men As Whole, Women In Parts (STUDY)

A glimpse at the magazine rack in any supermarket checkout line will tell you that women are frequently the focus of sexual objectification. Now, new research finds that the brain actually processes images of women differently than those of men, contributing to this trend.

Women are more likely to be picked apart by the brain and seen as parts rather than a whole, according to research published online June 29 in the European Journal of Social Psychology. Men, on the other hand, are processed as a whole rather than the sum of their parts.

"Everyday, ordinary women are being reduced to their sexual body parts," said study author Sarah Gervais, a psychologist at the University of Nebraska, Lincoln. "This isn't just something that supermodels or porn stars have to deal with." [6 Gender Myths, Busted]

Objectification hurts

Numerous studies have found that feeling objectified is bad for women. Being ogled can make women do worse on math tests, and self-sexualization, or scrutiny of one's own shape, is linked to body shame, eating disorders and poor mood.

But those findings have all focused on the perception of being sexualized or objectified, Gervais told LiveScience. She and her colleagues wondered about the eye of the beholder: Are people really objectifying women more than men?

To find out, the researchers focused on two types of mental processing, global and local. Global processing is how the brain identifies objects as a whole. It tends to be used when recognizing people, where it's not just important to know the shape of the nose, for example, but also how the nose sits in relation to the eyes and mouth. Local processing focuses more on the individual parts of an object. You might recognize a house by its door alone, for instance, while you're less likely to recognize a person's arm without the benefit of seeing the rest of their body.

If women are sexually objectified, people should process their bodies in a more local way, focusing on individual body parts like breasts. To test the idea, Gervais and her colleagues carried out two nearly identical experiments with a total of 227 undergraduate participants. Each person was shown non-sexualized photographs, each of either a young man or young woman, 48 in total. After seeing each original full-body image, the participants saw two side-by-side photographs. One was the original image, while the other was the original with a slight alteration to the chest or waist (chosen because these are sexualized body parts). Participants had to pick which image they'd seen before.

In some cases, the second set of photos zoomed in on the chest or waist only, asking participants to pick the body part they'd seen previously versus the one that had been altered.

Objectifying women

The results showed a clear schism between the images of men and women. When viewing female images, participants were better at recognizing individual parts than they were matching whole-body photographs to the originals. The opposite was true for male images: People were better at recognizing a guy as a whole than they were his individual parts.

People were also better at discerning women's individual body parts than they were at men's individual body parts, further confirming the local processing, or objectification, that was happening. [Cleavage Countdown: 8 Facts About Breasts]

"It's both men and women doing this to women," Gervais said. "So don't blame the men here."

In the second experiment, researchers preceded the body-part task with images of letters made up of a mosaic of tiny letters — an H made up of hundreds of little Ts, for example. They told some participants to identify the tiny letters, prompting their brains to engage in local processing. Other participants were asked to identify the big letter, revving up global processing. This latter group became less likely to objectify women, the researchers found. They no longer were better at recognizing a woman's parts than her whole body.

There could be evolutionary reasons that men and women process female bodies differently, Gervais said, but because both genders do it, "the media is probably a prime suspect."

"Women's bodies and their body parts are used to sell all sorts of products, but we are now for everyday, ordinary women, processing them in a similar way," she said.

Fortunately, the fact that the simple letter-mosaic task swept the effect away suggests that it's an easy habit to overcome, Gervais said. Being in a happy mood is related to global processing, she said, so avoiding blue funks could help you see people in a holistic way, as could simply reminding yourself to step back and look at the bigger picture.


Brain and General Sections - Psychology

Our Evolutionary Inheritance

The human brain as we know it today is like a city with a long history. It has its old sections where, in ancient times, the activities required for survival took place. It also has other, newer sections that developed around the older ones. Lastly, it has the modern section as we know it now, which was often built on the foundations of the other sections.

The reptilian brain first appeared in fish, nearly 500 million years ago. It continued to develop in amphibians and reached its most advanced stage in reptiles, roughly 250 million years ago.

The limbic system first appeared in small mammals, about 150 million years ago.

Lastly, the neo-cortex began its spectacular expansion in primates, scarcely 2 or 3 million years ago, as the genus Homo emerged.

The first time you observe the anatomy of the human brain, its many folds and overlapping structures can seem very confusing, and you may wonder what they all mean. But just like the anatomy of any other organ or organism, the anatomy of the brain becomes much clearer and more meaningful when you examine it in light of the evolutionary processes that created it.

Probably the best known model for understanding the structure of the brain in relation to its evolutionary history is the famous triune brain theory, which was developed by Paul MacLean and became very influential in the 1960s. Over the years since, however, several elements of this model have had to be revised in light of more recent neuroanatomical studies (see the first two history modules, to the left).

Keeping this in mind, MacLean's original model distinguished three different brains that appeared successively during evolution :

The reptilian brain, the oldest of the three, controls the body's vital functions such as heart rate, breathing, body temperature and balance. Our reptilian brain includes the main structures found in a reptile's brain: the brainstem and the cerebellum. The reptilian brain is reliable but tends to be somewhat rigid and compulsive. The limbic brain emerged in the first mammals. It can record memories of behaviours that produced agreeable and disagreeable experiences, so it is responsible for what are called emotions in human beings. The main structures of the limbic brain are the hippocampus, the amygdala, and the hypothalamus. The limbic brain is the seat of the value judgments that we make, often unconsciously, that exert such a strong influence on our behaviour. The neocortex first assumed importance in primates and culminated in the human brain with its two large cerebral hemispheres that play such a dominant role. These hemispheres have been responsible for the development of human language, abstract thought, imagination, and consciousness. The neocortex is flexible and has almost infinite learning abilities. The neocortex is also what has enabled human cultures to develop.

These three parts of the brain do not operate independently of one another. They have established numerous interconnections through which they influence one another. The neural pathways from the limbic system to the cortex, for example, are especially well developed.

For more about how these structures of the mammalian brain evolved together, click this link.


SAT / ACT Prep Online Guides and Tips

Mission control. Command center. Control tower. No, I'm not talking about space or your laptop hard drive, or even airport flight control. I'm talking about the human brain—the most complex and essential organ our bodies have. What is the brain structure? What part of the brain controls emotions?

Whether you're studying it in class, preparing for an AP exam, or just curious about brain structure, in this article, you'll learn about the main parts of brain anatomy and their functions and as well as get a general overview of the brain's supporting cast.


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General Psychology | A Tour of the Brain

To begin with, it should be noted that brain – is part of the central nervous system of human. As a fact, brain consists of a large number of neurons interconnected by synaptic connections. Interacting through these connections, neurons form complex electrical impulses that control the activity of the whole organism. It should be mentioned that brain function involves the processing of sensory information from the senses, planning, decision making, coordination, motion control, positive and negative emotions, attention and memory, perception and generation of speech, according to Brain (2010).

Human brain can be divided into three main parts: the forebrain, brainstem and cerebellum. The front brain consists of cerebral hemispheres, thalamus, hypothalamus and pituitary gland. The cerebral hemispheres – is the largest part of the brain in adult component of approximately 70% of its weight. The hemispheres are symmetrical and connected by a massive bundle of axons, providing information exchange. Each hemisphere is divided into four parts: the frontal, parietal, temporal, and occipital. In the cortex of the frontal lobes contains centers that regulate motor activity, and the centers of planning and foresight. In the cortex, parietal lobes, located behind the frontal lobe, there are zones of bodily sensations, including touch, and joint and muscle sense. In turn, posterior parts of the brain is the occipital lobe, which is located above the cerebellum, its bark contains a zone of visual sensations, according to Helen Philips (2008).

The brain stem is located at the base of the skull. It connects the spinal cord with the forebrain and consists of the medulla oblongata, bridge, middle, and diencephalon. The cerebellum is located below the occipital lobes of the cerebral hemispheres. The cerebellum provides the regulation of thin automatic movement in coordinating the activity of different muscle groups in the performance of stereotyped behavioral acts it also constantly monitors the position of the head, torso and extremities. Recent evidence suggests that the cerebellum plays an essential role in the formation of motor skills, helping to memorize the sequence of movements, according to Peter T. Fox, Jack L. Lancaster (2011).

As a fact, damage of at least one part of the brain can lead to very serious consequences, even death. Every main part of the brain is responsible for its function and its damage can cause disorders in the human organism. For example, the damage of cerebellum can lead to total or partial loss of motor coordination.


Cerebrum (Latin for "brain")

The cerebrum is the largest part of the brain in humans and the most recent in terms of our evolution. Higher cognitive functions such as judgment, imagination, perception, thought and decision-making occur here. The cerebrum also contains the cerebral cortex, a densely layered collection of neural pathways that give the brain’s exterior its wrinkled appearance. Scientists believe the frontal lobe in the front of the cerebral cortex is especially important for personality and intelligence. In addition, the cerebrum is divided into two symmetrical hemispheres that each play slightly different roles regarding speech, language learning, and vision.


Right or Left Brain

The functional sections or lobes of the brain are also divided into right and left sides. The right side and the left side of the brain are responsible for different but specific functions. General patterns of dysfunction can occur if an injury is on the right side, left side, or diffused (scattered across both sides). Understanding the associated issues with these particular situations can help caretakers or healthcare providers better understand the needs of an individual.


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