Cognitive neuropsychology

**Cognitive neuropsychology** is a subject in psychology. It is a combination of biology and cognitive psychology. These psychologists study human behavior and knowledge. This is a growing subject. Unlike cognitive neuroscience, cognitive neuropsychology pays attention to the mind rather than the brain.

Many scientists have worked to make cognitive neuropsychology. Their findings have created an understanding of the brain and how humans learn and do things.  Most of these scientists were not psychologists, but are known for their contributions to psychology. The technology today also helps advance what is known.  With brain imaging and other methods the brain can now be visualized. Cognitive neuroscience can be broken into different topics such as memory, attention, language, and emotion.

## History

Cognitive neuropsychology has its roots in research on language disorder that was done in the second half of the 19th century. One discovered that aphasia takes different forms depending on the (place or) location of brain damage; Knowledge from the research has been called a framework for understanding brain function (, or knowledge on which one has added additional (or more) knowledge).

The early history of cognitive neuropsychology begins with humans’ first acknowledgement of the mind/brain.  Beliefs in the importance of the mind/brain/head emerge as early as 4000BC with the Sumerians. Records of Sumerian intake of the poppy plant (which contains opium) include descriptions of the mind-altering affects. This suggests a reference to the brain. Another clue pointing towards acknowledgement of the brain is the discovery of skulls with holes drilled into them in 2000BC. Discovery of these skulls points to the brain as important to life. The motivation behind these drillings could be spiritual or medical.

The greatest contribution to early cognitive neuropsychology came from Egypt in 1700BC. This is the time of the Edwin Smith Surgical Papyrus. This document has the first written description of the human brain. These writings include descriptions of meninges and cerebrospinal fluid. Ancient Greek philosophers Aristotle, Plato and Almaceon  wrote about the form and function of the mind, psyche and soul. Aristotle saw the heart as the seat of the mind. He saw the heart containing all emotion and thinking. He also thought that the brain functioned to cool the heart down. Unlike Aristotle, Plato believed the brain to be the place for mental processes. With Aristotle we see the emergence of the dualistic view of mind and body. The dualistic versus monistic approach to the mind and brain is a debate dominating much of the history of cognitive neuroscience.

Galen was a Roman physician whose surgical descriptions of neurology helped describe the anatomy of the brain and neurological disorders. The Church was against human dissection. This limited the uncovering of new information.  Many unskilled physicians attempted dissections in secret, but there were no real, scientific discoveries in anatomy for centuries..

### 16th Century

During the renaissance cognitive neuropsychology began to develop a deeper understanding of the brain.  Vesalius wrote the first neuroscience textbook in 1543 and described the hydrocephalus in 1550. We also see the first use of the term “hippocampus” in 1564. This is when the brain was starting to be seen as a complex organ responsible for many operations of the body.  René Descartes was the most well known figure in cognitive neuropsychology at this time. Some of Descartes’ contributions stemmed from his interest in the nervous system and brain’s role in behavior. He thought that the nervous system was made up of hollow tubes which filled with “animal spirits” any time an action were to take place in that part of the body. His other contributions included the more developed notion of dualism. He hypothesized that the brain and mind are two separate entities that exist on their own but are depend on each other. He theorized that the pineal gland in the brain is where these two separate entities interacted. Descartes’ dualistic theory serves as his most influential contribution to cognitive neuropsychology.

### 18th Century

During the 18th century science began to develop. The first big advance was in human reflexes. These bodily reactions to stimuli or outside forces were observed and measured. This was found by studying axons and learning how signals travel in the human body. The development of the microscope helped. The brain's nerve fibers could now be seen and described.  Cerebrospinal fluid was found in the spaces of the brain and spinal cord. With that, the physiology of psychology began to take control of cognition. These findings are all still true today.

Electroconvulsion therapy  or electric shock therapy  was a method used to treat mental disorders.  This was used to treat blindness, hysteria, depression, and many other disorders. It was thought to be the way of the future in treating disabilities.

### 19th Century

The 19th century started the argument of localism vs. holism in cognitive neuropsychology. People were starting to question holism and explore the idea of localism. Localism means that the brain has individual areas that are responsible for certain actions in the body. The study of Phrenology started these localization theories. Phrenology is looking at the human skull and finding bumps to be measured.  Any strange bumps or shapes in the skull were then paired with intelligence or self traits in a person. These traits could include language, logic, and even love. If a part of the skull was pushed out it would mean that trait was better. This started localization theories

The next big thing in cognitive neuroscience has to do with ablation studies. This is when parts of the brain were removed so function could be measured without this brain area. For example, a neuropsychologist can remove the cerebellum. After it is removed, the animal's balance was not good. This links the cerebellum to balance.  As for brain damage, the most famous case is with Phineas Gage. He was working on the railroad when a piece of metal went through the front of his head. He did not die from this brain injury. However, his normal personality changed. This brought the idea that the frontal cortex, the part of the brain that was stabbed, controlled how a person acted.  Another study found the localization of language in the brain. Two separate scientists studied patients with language problems. They found that they had lesions or damage in two certain areas of their brain.  Broca's area controlled talking. Wernicke's area was found to control understanding of language.

This way of looking at problems in the brain led to studies of epileptic patients. An epileptic patient is a person that frequently suffers from seizures. These seizures were studied to learn more about how the brain sends electrical signals.  These electrical signals were then measured. It was found that each neuron can send a signal at certain speeds. These neurons were then dyed with a stain in order to be seen. At first it was thought that all nerves were connected like a web called a nerve net. However, with more complex stain it was found that each nerve is separate and can fire on their own.

### 20th Century

John B. Watson, who was a behaviorist in psychology, argued that cognition could not be studied scientifically because it could not be observed. For the first half of the 20th century, psychology  was dominated by behaviorism, which was mainly stimuli and a person’s response to it. Pierre Marie in 1906 criticized Broca, who was one of the first to create the field of Cognitive Neuropsychology. Henry Head in 1926 also attacked the whole field of cognitive neuropsychology.

Another reason why cognitive neuropsychology disappeared in the early twentieth century was because the science was not yet advanced enough. Many cognitive psychologists were also neurologists. These two fields of study were not separate as they are today. These neurologists wanted to study modules in the brain, and localize them with parts of the brain, but technology did not allow this yet. The methods used today were not yet created. They could only study where a person’s brain lesion was by doing an autopsy after the person was dead. This was a reason this field was criticized, and why many people believed cognition could not be studied scientifically.

In the middle of the twentieth century there was a transition called the 'Cognitive Revolution' in psychology. This is when psychologists began to agree that there were scientific ways to study cognition. These new beliefs about cognitive psychology were brought on by John C. Marshall's and Nora Newcombe’s study of reading, and Shallice and Warrington’s study of memory in the early 1970s. In the mid 1980s the first undergraduate book was published by Ellis & Young named _Human Cognitive Neuropsychology_. There was also  new technology that made it easier to study the brain and the mind.

An important feature of the later half of the twentieth century was the clear separation of cognitive neuropsychology and cognitive neuroscience. Cognitive neuropsychologists study the human mind after brain damage has occurred, and focus more on cognition. Cognitive neuroscientists focus more attention on the neurons. While the cognitive neuroscientists are concerned with how the brain works, and what parts of the brain is responsible for what functions, cognitive neuropsychologists want to study people with brain damage to try and see how the human mind works. With this information, they can formulate theories about the human mind, and also make better therapies for people with brain damage. Since every person’s brain damage is different, cognitive neuropsychologists study only single cases instead of groups of people, or syndromes. Psychologists study the mind by looking at people who lost some sort of function after brain damage occurred. For example, if a person could recognize both faces and objects before brain damage occurred, but then after brain damage in a certain part of the brain they could only recognize faces and not objects, then psychologists can make inferences about the functions in certain modules of the brain.

The late 20th century was also when they began using computational models of cognition. The psychologists would make theories and install them into a computer, then virtually damage the fake brain where the patient had damage. By doing this, they can get a better look at how the mind works. This is one way that technology has helped in studying the human mind. This, along with the invention of the devices to scan the brain, has made a big difference in cognitive neuropsychology.

Cognitive neuropsychologists use the method of double dissociation when studying the modules of the mind. This is when they use many patients who have had brain damage and try to figure out which parts of the brain are responsible for different cognition. This concept of modularity was developed by Jerry Fodor in his 1983 book The Modularity of the Mind. Psychologists disagree as to how much and which parts of the mind is constructed modules.

### 21st Century

In this century, cognitive neuropsychologists use many methods to study the mind. They use machines that scan the brain to see where the damage is, and then study cognitive abilities of these patients. They still use double dissociation for studying the patients, case studies, computational models, and many other features that were invented in the late twentieth century. With new technology, there is likely to be a lot of improvement in this field.

## Tools used in cognitive neuropsychology

Cognitive neuropsychology uses of investigations of people with problems of cognition to learn more about normal cognitive processes. This is possible through the many technological advances such as:
- Lesion and Behavior Approaches
- EEG
- Computerized Tomography (CAT) scan
- Positron Emission Tomography (PET) scan
- MRI
- fMRI