Cognitive neuropsychology
Encyclopedia
Cognitive neuropsychology is a branch of cognitive psychology
that aims to understand how the structure and function of the brain
relates to specific psychological processes. It places a particular emphasis on studying the cognitive effects of brain injury
or neurological illness with a view to inferring models of normal cognitive functioning. Evidence is based on case studies of individual brain damaged patients who show deficits in brain areas and from patients who exhibit double dissociations. From these studies researchers infer that different areas of the brain are highly specialised. It can be distinguished from cognitive neuroscience
which is also interested in brain damaged patients but is particularly focused on uncovering the neural mechanisms underlying cognitive processes.
The modern science of cognitive neuropsychology emerged during the 1960s. However there have been a series of influential studies during the last two centuries which have been critical in laying the foundations for studying brain impairment with a view to understanding normal psychological function.
The case of Phineas Gage
was one of the earliest in which a brain injury provided clues to the function of a particular brain area. Gage survived an 1848 accident in which an iron rod 1¼ inches in diameter was driven through one or both of his frontal lobes. Though he suffered no loss of sensory or motor function, Gage's consequent personality changes prevented his return to his position as a railway construction foreman (though most presentations of Gage greatly exaggerate his psychological changes—see Phineas Gage).
Similarly, Paul Broca
's 1861 post mortem study of an aphasic
patient, known as "Tan" after the only word which he could speak, showed that an area of the left frontal lobe
(now known as Broca's area
) was damaged. As Tan was unable to produce speech but could still understand it, Broca argued that this area might be specialised for speech production and that language
skills might be localised to this cortical
area.
Clues about the role of the occipital lobe
s in the visual system
were provided by soldiers returning from World War I
. The small bore ammunition often used in this conflict occasionally caused focal brain injuries. Studies of soldiers with such wounds to the back of their head showed that areas of blindness in the visual field
were dependent on which part of the occipital lobe had been damaged, suggesting that specific areas of the brain were responsible for sensation in specific visual areas, known as retinotopy
.
Studies on Patient HM
are commonly cited as some of the precursors, if not the beginning of modern cognitive neuropsychology. HM had parts of his medial temporal lobes surgically removed to treat intractable epilepsy
in 1953. The treatment proved successful in reducing his dangerous seizure
s, but left him with a profound but selective amnesia
. Because HM's impairment was caused by surgery, the damaged parts of his brain were precisely known, information which was usually not knowable in a time before accurate neuroimaging
became widespread. This allowed detailed connections to be made between theories of memory formation and the brain structures removed in HM.
These and similar studies had a number of important implications. The first is that certain cognitive processes (such as language) could be damaged separately from others, and so might be handled by distinct and independent cognitive and neural processes. (For more on the cognitive neuropsychological approach to language, see Eleanor Saffran
, among others.) The second is that such processes might be localised to specific areas of the brain. Whilst both of these claims are still controversial to some degree, the influence led to a focus on brain injury as a potentially fruitful way of understanding the relationship between psychology
and neuroscience
.
During the 1960s, information processing
became the dominant model in psychology
for understanding mental processes. This provided an important theoretical basis for cognitive neuropsychology, as it allowed an explanation of what areas of the brain might be doing (i.e. processing information in specific and specialised ways) and also allowed brain injury to be understood in abstract terms as impairment in the information processing abilities of larger cognitive systems.
are damaged, it is possible to infer previously undiscovered functional relationships. This is called the lesion
method.
By using this method, it should also be possible to discover whether a skill is handled by a single cognitive process or a combination of several working together. For example, if a theory states that reading and writing are simply different skills stemming from a single cognitive process, it should not be possible to find a person who, after brain injury, can write but not read or read but not write. This selective breakdown in skills suggests that different parts of the brain are specialised for the different processes and so the cognitive systems are separable.
The philosopher Jerry Fodor
has been particularly influential in cognitive neuropsychology, particularly with the idea that the mind, or at least certain parts of it, may be organised into independent modules. Evidence that cognitive skills may be damaged independently seem to support this theory to some degree, although it is clear that some aspects of mind (such as belief
for example) are unlikely to be modular. Ironically, Fodor (a strict functionalist
) rejects the idea that the neurological properties of the brain have any bearing on its cognitive properties and doubts the whole discipline of cognitive neuropsychology.
Cognitive neuropsychology also uses many of the same techniques and technologies from the wider science of neuropsychology
and fields such as cognitive neuroscience
. These may include neuroimaging
, electrophysiology
and neuropsychological tests to measure either brain function or psychological performance.
The principles of cognitive neuropsychology have recently been applied to mental illness
, with a view to understanding, for example, what the study of delusion
s may tell us about the function of normal belief. This relatively young field is known as cognitive neuropsychiatry
.
Cognitive psychology
Cognitive psychology is a subdiscipline of psychology exploring internal mental processes.It is the study of how people perceive, remember, think, speak, and solve problems.Cognitive psychology differs from previous psychological approaches in two key ways....
that aims to understand how the structure and function of the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
relates to specific psychological processes. It places a particular emphasis on studying the cognitive effects of brain injury
Acquired brain injury
An acquired brain injury is brain damage caused by events after birth, rather than as part of a genetic or congenital disorder such as fetal alcohol syndrome, perinatal illness or perinatal hypoxia. ABI can result in cognitive, physical, emotional, or behavioural impairments that lead to permanent...
or neurological illness with a view to inferring models of normal cognitive functioning. Evidence is based on case studies of individual brain damaged patients who show deficits in brain areas and from patients who exhibit double dissociations. From these studies researchers infer that different areas of the brain are highly specialised. It can be distinguished from cognitive neuroscience
Cognitive neuroscience
Cognitive neuroscience is an academic field concerned with the scientific study of biological substrates underlying cognition, with a specific focus on the neural substrates of mental processes. It addresses the questions of how psychological/cognitive functions are produced by the brain...
which is also interested in brain damaged patients but is particularly focused on uncovering the neural mechanisms underlying cognitive processes.
History
The case of Phineas Gage
Phineas Gage
Phineas P. Gage was an American railroad construction foreman now remembered for his improbablesurvival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe, and for that injury's reported effects on his personality and...
was one of the earliest in which a brain injury provided clues to the function of a particular brain area. Gage survived an 1848 accident in which an iron rod 1¼ inches in diameter was driven through one or both of his frontal lobes. Though he suffered no loss of sensory or motor function, Gage's consequent personality changes prevented his return to his position as a railway construction foreman (though most presentations of Gage greatly exaggerate his psychological changes—see Phineas Gage).
Paul Broca
Pierre Paul Broca was a French physician, surgeon, anatomist, and anthropologist. He was born in Sainte-Foy-la-Grande, Gironde. He is best known for his research on Broca's area, a region of the frontal lobe that has been named after him. Broca’s Area is responsible for articulated language...
's 1861 post mortem study of an aphasic
Aphasia
Aphasia is an impairment of language ability. This class of language disorder ranges from having difficulty remembering words to being completely unable to speak, read, or write....
patient, known as "Tan" after the only word which he could speak, showed that an area of the left frontal lobe
Frontal lobe
The frontal lobe is an area in the brain of humans and other mammals, located at the front of each cerebral hemisphere and positioned anterior to the parietal lobe and superior and anterior to the temporal lobes...
(now known as Broca's area
Broca's area
Broca's area is a region of the hominid brain with functions linked to speech production.The production of language has been linked to the Broca’s area since Pierre Paul Broca reported impairments in two patients. They had lost the ability to speak after injury to the posterior inferior frontal...
) was damaged. As Tan was unable to produce speech but could still understand it, Broca argued that this area might be specialised for speech production and that language
Language
Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...
skills might be localised to this cortical
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...
area.
Clues about the role of the occipital lobe
Occipital lobe
The occipital lobe is the visual processing center of the mammalian brain containing most of the anatomical region of the visual cortex. The primary visual cortex is Brodmann area 17, commonly called V1...
s in the visual system
Visual system
The visual system is the part of the central nervous system which enables organisms to process visual detail, as well as enabling several non-image forming photoresponse functions. It interprets information from visible light to build a representation of the surrounding world...
were provided by soldiers returning from World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
. The small bore ammunition often used in this conflict occasionally caused focal brain injuries. Studies of soldiers with such wounds to the back of their head showed that areas of blindness in the visual field
Visual field
The term visual field is sometimes used as a synonym to field of view, though they do not designate the same thing. The visual field is the "spatial array of visual sensations available to observation in introspectionist psychological experiments", while 'field of view' "refers to the physical...
were dependent on which part of the occipital lobe had been damaged, suggesting that specific areas of the brain were responsible for sensation in specific visual areas, known as retinotopy
Retinotopy
Retinotopy describes the spatial organization of the neuronal responses to visual stimuli. In many locations within the brain, adjacent neurons have receptive fields that include slightly different, but overlapping portions of the visual field. The position of the center of these receptive fields...
.
HM (patient)
Henry Gustav Molaison , famously known as HM or H.M., was an American memory disorder patient who was widely studied from late 1957 until his death...
are commonly cited as some of the precursors, if not the beginning of modern cognitive neuropsychology. HM had parts of his medial temporal lobes surgically removed to treat intractable epilepsy
Epilepsy
Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...
in 1953. The treatment proved successful in reducing his dangerous seizure
Seizure
An epileptic seizure, occasionally referred to as a fit, is defined as a transient symptom of "abnormal excessive or synchronous neuronal activity in the brain". The outward effect can be as dramatic as a wild thrashing movement or as mild as a brief loss of awareness...
s, but left him with a profound but selective amnesia
Amnesia
Amnesia is a condition in which one's memory is lost. The causes of amnesia have traditionally been divided into categories. Memory appears to be stored in several parts of the limbic system of the brain, and any condition that interferes with the function of this system can cause amnesia...
. Because HM's impairment was caused by surgery, the damaged parts of his brain were precisely known, information which was usually not knowable in a time before accurate neuroimaging
Neuroimaging
Neuroimaging includes the use of various techniques to either directly or indirectly image the structure, function/pharmacology of the brain...
became widespread. This allowed detailed connections to be made between theories of memory formation and the brain structures removed in HM.
These and similar studies had a number of important implications. The first is that certain cognitive processes (such as language) could be damaged separately from others, and so might be handled by distinct and independent cognitive and neural processes. (For more on the cognitive neuropsychological approach to language, see Eleanor Saffran
Eleanor Saffran
Eleanor M. Saffran was a researcher in the field of Cognitive Neuropsychology. Her interest in Neuropsychology began at the Baltimore City hospitals of Johns Hopkins University, where her research unit focussed on neurological patients with language or cognitive impairments. In papers published...
, among others.) The second is that such processes might be localised to specific areas of the brain. Whilst both of these claims are still controversial to some degree, the influence led to a focus on brain injury as a potentially fruitful way of understanding the relationship between psychology
Psychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...
and neuroscience
Neuroscience
Neuroscience is the scientific study of the nervous system. Traditionally, neuroscience has been seen as a branch of biology. However, it is currently an interdisciplinary science that collaborates with other fields such as chemistry, computer science, engineering, linguistics, mathematics,...
.
During the 1960s, information processing
Information processing
Information processing is the change of information in any manner detectable by an observer. As such, it is a process which describes everything which happens in the universe, from the falling of a rock to the printing of a text file from a digital computer system...
became the dominant model in psychology
Psychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...
for understanding mental processes. This provided an important theoretical basis for cognitive neuropsychology, as it allowed an explanation of what areas of the brain might be doing (i.e. processing information in specific and specialised ways) and also allowed brain injury to be understood in abstract terms as impairment in the information processing abilities of larger cognitive systems.
Methods
By understanding what a person can no longer do, and correlating this with a knowledge of exactly which parts of the nervous systemNervous system
The nervous system is an organ system containing a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals between different parts of its body. In most animals the nervous system consists of two parts, central and peripheral. The central nervous...
are damaged, it is possible to infer previously undiscovered functional relationships. This is called the lesion
Lesion
A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
method.
By using this method, it should also be possible to discover whether a skill is handled by a single cognitive process or a combination of several working together. For example, if a theory states that reading and writing are simply different skills stemming from a single cognitive process, it should not be possible to find a person who, after brain injury, can write but not read or read but not write. This selective breakdown in skills suggests that different parts of the brain are specialised for the different processes and so the cognitive systems are separable.
The philosopher Jerry Fodor
Jerry Fodor
Jerry Alan Fodor is an American philosopher and cognitive scientist. He holds the position of State of New Jersey Professor of Philosophy at Rutgers University and is the author of many works in the fields of philosophy of mind and cognitive science, in which he has laid the groundwork for the...
has been particularly influential in cognitive neuropsychology, particularly with the idea that the mind, or at least certain parts of it, may be organised into independent modules. Evidence that cognitive skills may be damaged independently seem to support this theory to some degree, although it is clear that some aspects of mind (such as belief
Belief
Belief is the psychological state in which an individual holds a proposition or premise to be true.-Belief, knowledge and epistemology:The terms belief and knowledge are used differently in philosophy....
for example) are unlikely to be modular. Ironically, Fodor (a strict functionalist
Functionalism (philosophy of mind)
Functionalism is a theory of the mind in contemporary philosophy, developed largely as an alternative to both the identity theory of mind and behaviourism. Its core idea is that mental states are constituted solely by their functional role — that is, they are causal relations to other mental...
) rejects the idea that the neurological properties of the brain have any bearing on its cognitive properties and doubts the whole discipline of cognitive neuropsychology.
Cognitive neuropsychology also uses many of the same techniques and technologies from the wider science of neuropsychology
Neuropsychology
Neuropsychology studies the structure and function of the brain related to specific psychological processes and behaviors. The term neuropsychology has been applied to lesion studies in humans and animals. It has also been applied to efforts to record electrical activity from individual cells in...
and fields such as cognitive neuroscience
Cognitive neuroscience
Cognitive neuroscience is an academic field concerned with the scientific study of biological substrates underlying cognition, with a specific focus on the neural substrates of mental processes. It addresses the questions of how psychological/cognitive functions are produced by the brain...
. These may include neuroimaging
Neuroimaging
Neuroimaging includes the use of various techniques to either directly or indirectly image the structure, function/pharmacology of the brain...
, electrophysiology
Electrophysiology
Electrophysiology is the study of the electrical properties of biological cells and tissues. It involves measurements of voltage change or electric current on a wide variety of scales from single ion channel proteins to whole organs like the heart...
and neuropsychological tests to measure either brain function or psychological performance.
The principles of cognitive neuropsychology have recently been applied to mental illness
Mental illness
A mental disorder or mental illness is a psychological or behavioral pattern generally associated with subjective distress or disability that occurs in an individual, and which is not a part of normal development or culture. Such a disorder may consist of a combination of affective, behavioural,...
, with a view to understanding, for example, what the study of delusion
Delusion
A delusion is a false belief held with absolute conviction despite superior evidence. Unlike hallucinations, delusions are always pathological...
s may tell us about the function of normal belief. This relatively young field is known as cognitive neuropsychiatry
Cognitive neuropsychiatry
Cognitive neuropsychiatry is a sub-discipline of psychology and psychiatry that aims to understand mental illness and psychopathology in terms of models of normal psychological function. It is also a way of uncovering normal psychological processes by studying the effects of their change or...
.
See also
- Capgras delusionCapgras delusionThe Capgras delusion theory is a disorder in which a person holds a delusion that a friend, spouse, parent, or other close family member has been replaced by an identical-looking impostor...
- Clive WearingClive WearingClive Wearing is a British musicologist, conductor, and keyboardist suffering from an acute and long-lasting case of anterograde and retrograde amnesia, meaning that he lacks the ability to form new memories.-Musical career:...
- cognitive biasCognitive biasA cognitive bias is a pattern of deviation in judgment that occurs in particular situations. Implicit in the concept of a "pattern of deviation" is a standard of comparison; this may be the judgment of people outside those particular situations, or may be a set of independently verifiable...
- cognitive neuropsychiatryCognitive neuropsychiatryCognitive neuropsychiatry is a sub-discipline of psychology and psychiatry that aims to understand mental illness and psychopathology in terms of models of normal psychological function. It is also a way of uncovering normal psychological processes by studying the effects of their change or...
- Cotard delusionCotard delusionThe Cotard delusion or Cotard's syndrome or Walking Corpse Syndrome is a rare neuropsychiatric disorder in which people hold a delusional belief that they are dead , do not exist, are putrefying, or have lost their blood or internal organs...
- emotion and memoryEmotion and memoryEmotion can have a powerful impact on memory. Numerous studies have shown that the most vivid autobiographical memories tend to be of emotional events, which are likely to be recalled more often and with more clarity and detail than neutral events....
- ErotomaniaErotomaniaErotomania is a type of delusion in which the affected person believes that another person, usually a stranger or famous person, is in love with him or her. The illness often occurs during psychosis, especially in patients with schizophrenia or bipolar mania...
- face perceptionFace perceptionFace perception is the process by which the brain and mind understand and interpret the face, particularly the human face.The human face's proportions and expressions are important to identify origin, emotional tendencies, health qualities, and some social information. From birth, faces are...
- Fregoli delusionFregoli delusionThe Fregoli delusion or the delusion of doubles is a rare disorder in which a person holds a delusional belief that different people are in fact a single person who changes appearance or is in disguise...
- HM (patient)HM (patient)Henry Gustav Molaison , famously known as HM or H.M., was an American memory disorder patient who was widely studied from late 1957 until his death...
- neuropsychological testNeuropsychological testNeuropsychological tests are specifically designed tasks used to measure a psychological function known to be linked to a particular brain structure or pathway. Tests are used for research into brain function and in a clinical setting for the diagnosis of deficits. They usually involve the...
- Phineas GagePhineas GagePhineas P. Gage was an American railroad construction foreman now remembered for his improbablesurvival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe, and for that injury's reported effects on his personality and...
- primary sensory cortex
- prosopagnosiaProsopagnosiaProsopagnosia is a disorder of face perception where the ability to recognize faces is impaired, while the ability to recognize other objects may be relatively intact...
- retinotopyRetinotopyRetinotopy describes the spatial organization of the neuronal responses to visual stimuli. In many locations within the brain, adjacent neurons have receptive fields that include slightly different, but overlapping portions of the visual field. The position of the center of these receptive fields...
- CDR Computerized Assessment SystemCDR Computerized Assessment SystemThe CDR Computerized Assessment System is a computerized battery of cognitive tests designed in the late 1970s by Professor Keith Wesnes at the University of Reading in Berkshire, England, for repeated testing in clinical trails...