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Cognitive neuropsychology is a branch of
cognitive psychology Cognitive psychology is the scientific study of mental processes such as attention, language use, memory, perception, problem solving, creativity, and reasoning. Cognitive psychology originated in the 1960s in a break from behaviorism, which ...
that aims to understand how the structure and function of the
brain A brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as Visual perception, vision. I ...
relates to specific
psychological Psychology is the scientific study of mind and behavior. Psychology includes the study of conscious and unconscious phenomena, including feelings and thoughts. It is an academic discipline of immense scope, crossing the boundaries bet ...
processes. Cognitive psychology is the science that looks at how mental processes are responsible for our cognitive abilities to store and produce new memories, produce language, recognize people and objects, as well as our ability to reason and problem solve. Cognitive neuropsychology places a particular emphasis on studying the
cognitive Cognition refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought ...
effects of brain injury or neurological illness with a view to inferring models of normal
cognitive Cognition refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought ...
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. Double dissociations involve two patients and two tasks. One patient is impaired at one task but normal on the other, while the other patient is normal on the first task and impaired on the other. For example, patient A would be poor at reading printed words while still being normal at understanding spoken words, while the patient B would be normal at understanding written words and be poor at understanding spoken words. Scientists can interpret this information to explain how there is a single cognitive module for word comprehension. From studies like these, researchers infer that different areas of the brain are highly specialised. Cognitive neuropsychology 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.


History

Cognitive neuropsychology has its roots in the diagram making approach to language disorder that started in the second half of the 19th century. The discovery that
aphasia Aphasia is an inability to comprehend or formulate language because of damage to specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine but aphasia due to stroke is estimated to be 0.1–0.4% in ...
took different forms depending on the location of brain damage provided a powerful framework for understanding brain function. In 1861 Paul Broca, reported a
post mortem An autopsy (post-mortem examination, obduction, necropsy, or autopsia cadaverum) is a surgical procedure that consists of a thorough examination of a corpse by dissection to determine the cause, mode, and manner of death or to evaluate any d ...
study of an
aphasic Aphasia is an inability to comprehend or formulate language because of damage to specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine but aphasia due to stroke is estimated to be 0.1–0.4% in t ...
patient who was speechless apart from a single nonsense word: "Tan". Broca showed that an area of the left
frontal lobe The frontal lobe is the largest of the four major lobes of the brain in mammals, and is located at the front of each cerebral hemisphere (in front of the parietal lobe and the temporal lobe). It is parted from the parietal lobe by a groove be ...
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 is a structured system of communication. The structure of a language is its grammar and the free components are its vocabulary. Languages are the primary means by which humans communicate, and may be conveyed through a variety of ...
skills might be localized to this cortical area. Broca did a similar study on another patient, Lelong, a few weeks later. Lelong, like Tan, could understand speech but could only repeat the same 5 words. After examining his brain, Broca noticed that Lelong had a lesion in approximately the same area as his patient Tan. He also noticed that in the more than 25 patients he examined with
aphasia Aphasia is an inability to comprehend or formulate language because of damage to specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine but aphasia due to stroke is estimated to be 0.1–0.4% in ...
, they all had lesions to the left frontal lobe but there was no damage to the right hemisphere of the brain. From this he concluded that the function of speech was probably localized in the inferior frontal gyrus of the left hemisphere of the brain, an area now known as
Broca's area Broca's area, or the Broca area (, also , ), is a region in the frontal lobe of the dominant hemisphere, usually the left, of the brain with functions linked to speech production. Language processing has been linked to Broca's area since Pier ...
. Karl Wernicke subsequently reported patients with damage further back in the temporal lobe who could speak but were unable to understand what was said to them, providing evidence for two potentially interconnected language centres. These clinical descriptions were integrated into a theory of language organisation by Lichtheim. Subsequently, these models were used and developed to inform Dejerine's account of reading,
Liepmann Liepmann is a surname. Notable people with the surname include: * Hans W. Liepmann (1914–2009), German American engineer, emeritus professor of aeronautics at the California Institute of Technology * Heinrich Liepmann (1904-1983), German-British ...
's theory of action and Lissauer's 1890 account of object recognition and Lewandowsky and Stadelmann's 1908 account of calculation. However, the early 20th century saw a reaction to the overly-precise accounts of the diagram making neurologists. Pierre Marie challenged conclusions against previous evidence of Broca's areas in 1906 and Henry Head attacked the whole field of cerebral localisation 1926. The modern science of cognitive neuropsychology emerged during the 1960s stimulated by the insights of the neurologist Norman Geschwind who demonstrated that the insights of Broca and Wernicke were still clinically relevant. The other stimulus to the discipline was the "Cognitive Revolution" and the growing science of
cognitive psychology Cognitive psychology is the scientific study of mental processes such as attention, language use, memory, perception, problem solving, creativity, and reasoning. Cognitive psychology originated in the 1960s in a break from behaviorism, which ...
which had emerged as a reaction to
behaviorism Behaviorism is a systematic approach to understanding the behavior of humans and animals. It assumes that behavior is either a reflex evoked by the pairing of certain antecedent stimuli in the environment, or a consequence of that individual ...
in the mid 20th century. Psychologists in the mid-1950s acknowledged that the structure of mental information-processing systems could be investigated in scientifically acceptable ways. They developed and applied new cognitive processing models to explain experimental data from not only studies of speech and language but also those of selective attention.Coltheart, M. (2008). Cognitive neuropsychology. Scholarpedia, 3(2), 3644. doi: 10.4249/scholarpedia.3644. Cognitive psychologists and clinical neuropsychologists developed more research collaborations to gain a better understanding of these disorders. The rebirth of neuropsychology was marked by the publishing of two seminal collaborative papers from Marshall & Newcombe (1966) on reading and Warrington & Shallice (1969) on memory. Subsequently, work by pioneers such as Elizabeth Warrington, Brenda Milner, Tim Shallice, Alan Baddeley and
Lawrence Weiskrantz Lawrence Weiskrantz (28 March 1926 – 27 January 2018) was a British neuropsychologist. Weiskrantz is credited with discovering the phenomenon of blindsight, and with establishing the role of the amygdala in emotional learning and emotional be ...
demonstrated that neurological patients were an important source of data for cognitive psychologists. It took less than one decade for neuropsychology to be fully re-established. More achievements in neuropsychology were recognized: the establishment of the first major book discussing neuropsychology using a cognitive approach, ''Deep Dyslexia'', in 1980 after a scientific meeting about the topic in Oxford in 1977, the birth of the ''Cognitive Neuropsychology'' journal in 1984, and the publishing of the first textbook of neuropsychology, ''Human Cognitive Neuropsychology'' in 1988. A particular area of interest was memory. Patients with
amnesia Amnesia is a deficit in memory caused by brain damage or disease,Gazzaniga, M., Ivry, R., & Mangun, G. (2009) Cognitive Neuroscience: The biology of the mind. New York: W.W. Norton & Company. but it can also be caused temporarily by the use ...
caused by injuries to the
hippocampus The hippocampus (via Latin from Greek , 'seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic syste ...
in the temporal cortex and midbrain areas (especially the
mamillary bodies The mammillary bodies are a pair of small round bodies, located on the undersurface of the brain that, as part of the diencephalon, form part of the limbic system. They are located at the ends of the anterior arches of the fornix. They consis ...
) were of early interest. A patient with severe case of amnesia will not be able to remember meeting the examiner if they leave the room and return, let alone events of the previous day (
episodic memory Episodic memory is the memory of everyday events (such as times, location geography, associated emotions, and other contextual information) that can be explicitly stated or conjured. It is the collection of past personal experiences that occurred ...
), but they will still be able to learn how to tie their shoes ( procedural memory), remember a series of numbers for a few seconds (
short term memory Short-term memory (or "primary" or "active memory") is the capacity for holding a small amount of information in an active, readily available state for a short interval. For example, short-term memory holds a phone number that has just been recit ...
or
working memory Working memory is a cognitive system with a limited capacity that can hold information temporarily. It is important for reasoning and the guidance of decision-making and behavior. Working memory is often used synonymously with short-term memory, ...
) and be able to recall historical events they have learned in school (
semantic memory Semantic memory refers to general world knowledge that humans have accumulated throughout their lives. This general knowledge (word meanings, concepts, facts, and ideas) is intertwined in experience and dependent on culture. We can learn abou ...
). By contrast, patients may lose their short term memory abilities while retaining their long term memory functions. Many other studies like this have been done in the field of neuropsychology examining lesions and the effect they have on certain areas of the brain and their functions. Studies on the amnesic patient
Henry Molaison Henry Gustav Molaison (February 26, 1926 – December 2, 2008), known widely as H.M., was an American who had a bilateral medial temporal lobe, temporal lobectomy to surgically resect the anterior two thirds of his Hippocampus, hippocampi, p ...
, formerly known as patient H.M., are commonly cited as some of the precursors, if not the beginning of modern cognitive neuropsychology. Molaison had parts of his medial temporal lobes surgically removed to treat intractable
epilepsy Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrica ...
in 1953. Much of the hippocampus was also removed along with the medial temporal lobes. The treatment proved successful in reducing his dangerous
seizure An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with lo ...
s, but left him with a profound but selective amnesia. After the surgery, Molaison was able to remember some big events from before the surgery, such as the stock market crash in 1929, but was confused about many others and could no longer form new memories. This accidental experiment showed scientists how the brain processes different types of memory. Because Molaison's impairment was caused by surgery, the damaged parts of his brain were known, information which was usually not knowable in a time before accurate
neuroimaging Neuroimaging is the use of quantitative (computational) techniques to study the structure and function of the central nervous system, developed as an objective way of scientifically studying the healthy human brain in a non-invasive manner. Incr ...
became widespread. Scientists concluded that while the hippocampus is needed in the creation of new memories, it is not needed in the retrieval of old ones; they are two separate processes. They also realized that the hippocampus and the medial temporal lobes, both of the areas removed from Molaison, are the areas responsible for converting short term memory to long term memory. Much of the early work of cognitive neuropsychology was carried out with limited reference to the detailed localisation of brain pathology.
Neuroimaging Neuroimaging is the use of quantitative (computational) techniques to study the structure and function of the central nervous system, developed as an objective way of scientifically studying the healthy human brain in a non-invasive manner. Incr ...
was relatively imprecise and other anatomically based techniques were also limited. The emphasis of many researchers as late as 1990 was on the analysis of patterns of cognitive deficit rather than on where the injury was located. Despite the lack of detailed anatomical data, studies of reading, language and memory had a number of important implications. The first is that certain
cognitive Cognition refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought ...
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 M. Saffran (May 16, 1938 – November 23, 2002), an American neuroscientist, was a researcher in the field of Cognitive Neuropsychology. Her interest in Neuropsychology began at the Baltimore City hospitals of Johns Hopkins University, wher ...
, among others.) The second is that such processes might be localized 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 is the science, scientific study of mind and behavior. Psychology includes the study of consciousness, conscious and Unconscious mind, unconscious phenomena, including feelings and thoughts. It is an academic discipline of immens ...
and
neuroscience Neuroscience is the science, scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a Multidisciplinary approach, multidisciplinary science that combines physiology, an ...
.


Methods

A key approach within cognitive neuropsychology has been to use single case studies and dissociation as a means of testing theories of cognitive function. 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 specialized for the different processes and so the cognitive systems are separable. The philosopher
Jerry Fodor Jerry Alan Fodor (; April 22, 1935 – November 29, 2017) was an American philosopher and the author of many crucial works in the fields of philosophy of mind and cognitive science. His writings in these fields laid the groundwork for the modul ...
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 A belief is an attitude that something is the case, or that some proposition is true. In epistemology, philosophers use the term "belief" to refer to attitudes about the world which can be either true or false. To believe something is to tak ...
for example) are unlikely to be modular. 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. With improved neuroimaging techniques, it has been possible to correlate patterns of impairment with a knowledge of exactly which parts of the
nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes ...
are damaged, allowing previously undiscovered functional relationships to be explored (the ''
lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classif ...
method''). Contemporary cognitive neuropsychology uses many of the same techniques and technologies from the wider science of
neuropsychology Neuropsychology is a branch of psychology concerned with how a person's cognition and behavior are related to the brain and the rest of the nervous system. Professionals in this branch of psychology often focus on how injuries or illnesses of t ...
and fields such as cognitive neuroscience. These may include
neuroimaging Neuroimaging is the use of quantitative (computational) techniques to study the structure and function of the central nervous system, developed as an objective way of scientifically studying the healthy human brain in a non-invasive manner. Incr ...
,
electrophysiology Electrophysiology (from Greek , ''ēlektron'', "amber" etymology of "electron"">Electron#Etymology">etymology of "electron" , ''physis'', "nature, origin"; and , ''-logia'') is the branch of physiology that studies the electrical properties of bi ...
and
neuropsychological tests Neuropsychological tests are specifically designed tasks that are 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 ...
to measure either brain function or psychological performance. Useful technology in cognitive neuropsychology includes positron-emission tomography (PET) and functional magnetic resonance imaging (fMRI). These techniques make it possible to identify the areas of the brain responsible for performing certain cognitive tasks by measuring blood flow in the brain. PET scans sense the low-level radiation in the brain and produce 3-D images, whereas an fMRI works on a magnetic signal and is used to “map the brain”. Electroencephalography (EEG) records the brain’s electrical activity and can identify changes that occur over milliseconds. EEG is often used in patients with epilepsy to detect seizure activity. The principles of cognitive neuropsychology have recently been applied to
mental illness A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitt ...
, with a view to understanding, for example, what the study of
delusion A delusion is a false fixed belief that is not amenable to change in light of conflicting evidence. As a pathology, it is distinct from a belief based on false or incomplete information, confabulation, dogma, illusion, hallucination, or som ...
s may tell us about the function of normal belief. This relatively young field is known as
cognitive neuropsychiatry Cognitive neuropsychiatry is a growing multidisciplinary field arising out of cognitive psychology and neuropsychiatry that aims to understand mental illness and psychopathology in terms of models of normal psychological function. A concern with ...
.


See also


References


Further reading

* {{DEFAULTSORT:Cognitive Neuropsychology Neuropsychology Cognition