Introduction:
Neuropsychology deals with cognitive functions in dealing with the brain structures. In psychology, it borrows its language as semiotics is evaluated in terms of behavior.
Neurology, it keeps the constant reference to the injury or physiological disorganization that is responsible for disturbances.
Structured as a discipline, neuropsychology is based on the idea that psychological functioning may be related to brain function.
The term neuropsychology seems used for the first time by Osler in 1913 to designate the science of the relationship between mental illness and brain.
Next to the traditional clinical neuropsychology that, in France, is implanted in most university hospitals in the last 30 years, cognitive neuropsychology adds a new dimension. His priority is the purely cognitive analysis of disorders observed in brain-injured subjects.
One more favors the study of structure / function relationships, but the cognitive processes themselves.
By cognitive, means the brain’s ability to select, process, store, produce and use information to solve problems, reason, adapt to the environment, meet the needs and desires. No theory of cognition can not however be complete unless it included the emotional and motivational concepts.
One of the objectives of neuropsychology is to better describe the interactions and dysfunction between cognition, emotion and behavior, initially in the neurological field, and more recently in the psychiatric field.
The concepts and methods of neuropsychology are used by cognitive psychopathology with characteristics experimentation and cognitive study of psychopathology.
In psychiatry, it is the research on schizophrenia and anxiety and depressive disorders that benefit from advances in neuropsychology.
Another pragmatic goal of neuropsychology is to propose a rehabilitative care.
For neuropsychologists who are interested in brain injury or psychiatric patients, it is certainly to improve a given function taken in isolation, such as memory or attention, but especially to take into account the impact of these dysfunctions on behavior in everyday life, monitor their impact and help topics to reintegrate.
History of neuropsychology:
If the birth of neuropsychology generally merges with that of aphasia, the historical development of knowledge is older.“Looking at a man who pressed the temple, when called, he did not respond, he lost the use of the word” notes scribe.
The role of the brain in the control of movement and speech is described in ancient Egypt. However, the Egyptians, the Mesopotamians and the Hebrews seem to have assessed the implications of these observations that fall into the oubli.Pendant the Hellenistic period, history of brain function coincides with the advent of mathematical and physical sciences.
For Democritus, thought and feelings have a material basis and depend on a variety of common atoms in the body and to the brain: “The brain monitors as a sentinel citadel body entrusted to his care.”
Plato is part of the “soul” of feeling responsible, reason and movements in the brain.
Céphalocentrique this thesis is strengthened and enriched by observations of Hippocrates.
The brain is the interpreter of consciousness. However, for Empedocles and Aristotle, the soul does not lie in the brain but in the heart that is the “acropolis of the body.”
These two theories are in competition until the late Middle Ages.
This concern, which is to seek to structure the soul, is the basis of neuropsychology.
The diversity of the word soul having no equivalent that its vagueness, Galen divided into three faculties: driving, sensible and reasonable. The latter includes the imagination, reason and memory. With the advent of the Renaissance anatomists Vesalius and Willis, the Aristotelian cardiocentrisme back in favor of the doctrine céphalocentrique.
The faculties are located in the ventricles, and in the cortex.
Willis, Senior neuroanatomist seventeenth century, combines common sense and voluntary movements striatum, imagination to the corpus callosum, the memory to the cerebral cortex and the instinctive behavior in the central part of the brain.
The accuracy of its work, the extent of his views, make him the precursor theories about cerebral localization of the nineteenth and twentieth centuries.
Descartes, opposing spirit and matter, robs the spirit of its physical medium. It isolates the mental states of their biological soil and prepares the ground for a mechanistic and dualistic thinking.
In the early nineteenth century through the work of Gall and Spurtzheim, a new doctrine, phrenology, will closely link the mind and brain and make the cerebral cortex the seat of the intellectual faculties.
It is in this intellectual movement that Bouillaud locates the language in previous lobules of the brain and that Broca presents the Anthropological Society known communication entitled “Loss of speech, chronic softening and partial destruction of the left anterior lobe of the brain “.
This is the first observation clinicopathological leading to the individualization of a “center” cerebral functional. With Gall Bouillaud, Broca and Wernicke, born the current locator.
This is a real geography of the brain, sort of psychoanatomique mapping.
In opposition to the surveyors of the brain, voice growing protest against the excesses committed from these schemes.
Initiated by Marie and Von Monakow that formally separates the location of a function with that of a lesion, a new antilocalisationniste violently current will develop.
Thus, Goldstein is the origin of the holistic current from the study of the wounded in the Great War.
After World War II, conflict between globalists and localizationists fade, although localizationists models, connectionist develop because neuropsychology must incorporate the contribution of statistical analysis, linguistics, cognitive psychology and techniques brain imaging.
After the advent of the two-dimensional brain mapping and before the birth of globalist current hierarchical models appear in three dimensions.
This approach, resituated in an evolutionary framework, not only opens the possibility to see the brain in a hierarchical organization into strata, witness to history of the evolution of species, but also to locate the “animal” part of man , his emotional experiences, deep in the brain.
The neuroanatomist Papez was inspired by the idea that the Jacksonian emotional experience would be located in the lower layers of the brain such as the hippocampus, hypothalamus and amygdala.
In 1949, Mac Lean offers a hierarchical and evolutionary design of the location of emotion.
He designs the structures described by Papez as an intermediate layer, advancing the idea that the cerebral cortex of humans and this interim system would be superimposed functioning model proposed by Freud, that is to say, the rational ego and it unconscious.
The intermediate level would occupy the structures described by the term limbic system, responsible for the expression of emotions, especially aggression and sexual behavior.
It remains to understand how this is structured intermediate layer compared to cortical upper layers, to participate in consciously perceived emotion and allow the knowledge of the world as an emotional mode.
This brief history would be incomplete if we did say a few words of Luria, which considers the higher cortical functions as the fruit of the integrating work of several brain areas working in concert.
Conducting a heuristic synthesis of various neuropsychological designs, localizationists, associationists and globalists, Luria contributed to the modern approach in neuropsychology, that integrates the study of cognitive functions but also behavioral and emotional.
Currently, this approach is characterized by the synthesis of clinical data (detailed assessment of patients), biological (brain imaging, biomarkers) and theoretical (cognitive patterns).
The collection of clinical data has become more objective and scientific through the development of assessment tools such as tests, scales and questionnaires.
The development of functional brain imaging techniques allows to visualize and better understand the structures and neural networks involved in various normal and abnormal neurological or psychiatric origin process.
Definitions of neuropsychology:
“The term neuropsychology, it seems that one is entitled to define a specific field of neurology, mainly cortical, which interests both neurologists, clinicians, psychiatrists, psychologists, psycho-physiologists and neurophysiologists.
This area focuses on disorders of higher mental activities …, and especially language disorders, gesture, perception … “.
Although restrictive, this definition remains historically based.
It was completed in 1972 by Hécaen “Neuropsychology is the hinge of a part of neurosciences on the other behavioral science and human relations …”.
According Botez, clinical neuropsychology, like behavioral neurology, has as object the study of the relationship between brain and behavior.
MENTAL FUNCTION:
All mental activity necessarily mean brain activity.
Neuropsychological vocabulary is heir to the concept of mental faculties (language, memory, perception …) which express only type of behavior.
This typology, facing a lesion seat, leads to the concept of “brain functions”; sometimes prefers the term “higher activity” because considered more physiological.
These activities that allow us to know the world, hence the name of cognitive activities, are expressed through behavior. The behaviors are considered the responses of the individual in a given context.
The higher activities can be gestural, including finalized movements of communication, use, construction, cladding (praxis).
They can be perceptual (gnostic), verbal (phasic), attentional, memory and intellectual. One adds the executive, considered the ability to anticipate, plan, initiate a finalized action and achieve. Usually, emotions are excluded, but arbitrarily, the so-called higher activities.
In the preface to his book “The higher cortical functions in humans,” Luria considered appropriate to incorporate new knowledge, “many studies have been devoted in recent years to the detailed study of functions and limbic systems disruptions in the emotional sphere as well as memory processes resulting from their injury. “
The relationship between cognition and emotion are the subject of heated debate among scientists, some believing that cognition and emotion must be strictly separated and treated as independent functions, while, for others, the emotion is an aspect of cognition.
EMOTIONS AND BEHAVIOUR:
The concept of emotion (ex-movere Latin outward movement) generally includes the physical and mental phenomena that accompany perception, expression and experience of affect, and somatic changes that accompany them.
Two major dichotomies have been highlighted in studies of the anatomical substrate of emotions.
The first classic, is in favor of a subcortical location of the brain mechanisms involved in emotions.
There is indeed a considerable sum of arguments suggesting that the mechanisms of emotions and motivation are underpinned by the gray brain structures such as the amygdala, the septal nuclei, striatum, hypothalamus.
A second dichotomy, more recent, suggests that the right and left hemispheres are not involved in the same way in the emotional behavior and the right hemisphere would play a critical role. Some studies argue for dominance of the right hemisphere for all the emotional manifestations, particularly the identification of emotional and facial expressions.
Other studies suggest different hemispheric specializations according to the positive or negative valence emotions.
There seems close relations between the two dichotomies because the right hemisphere superiority for emotional functions more respect basic levels (subcortical) emotions and the automatic responses of the subject, while the left hemisphere is more involved in cortical functions of inhibition and control of subcortical emotional mechanisms.
It is customary to bring all these structures to as the limbic system.
The orbitofrontal cortex is involved in behavior and affectivity. This brain area is related to capacities of intention and attention, essential for the perception of events in time and for verbal control of motor functions.
The term “front”, applied to stroke patients, refers to disorders of the character and personality type disinhibition and egocentrism by altering the perception of the surrounding reality.
In light of the case Phineas Gage, Damasio reconsidered observable anomalies in this type of lesions under the term “acquired sociopathy”.
The role of the orbital cortex intervene in social adjustment, regulation of moral judgment and behavior underpinned by ethical concepts.
Deficits of motivation and action are known under different names: “apathy”, “abulia”, “loss of psychic self-activation” or “athymhormique syndrome.”
Phineas Gage, 25 years old in 1848, had the brain pierced by a crowbar after an explosion.
Once recovered, apparently cured his entourage realized that he was no longer the same and its new personality traits contrasted sharply with moderation and great strength of character he had shown before the accident . He had become rude, capricious, unstable and unable to plan and make choices that were once familiar to him.
Intelligence, assessed by tests, were normal. He lost all socio-professional and emotional status, and died at the age of 38, in a state of destitution and total abandonment.
With current data neuroanatomy and neuroimaging, Damasio has implemented a new technique called brainwox who reconstructed the brain in three dimensions. This computer technology has allowed a posteriori to accurately visualize different brain lesions of the brain of Phineas Gage.
Thus, the bar had damaged the left cheek, the left frontal lobe and cranial convexity.
Contributions of neuropsychology for research in psychopathology
ATTENTION AND ANXIETY:
Anxiety:
In clinical practice as research, anxiety disorders refer to various diagnostic categories.
In the Diagnostic and statistical manual of mental disorders fourth edition, these disorders fall into generalized anxiety disorder, panic disorder, phobic disorders and posttraumatic stress disorder.
Assessments of anxiety according to other criteria and dimensions have been proposed, for example with the STAI Anxiety Inventory Spielberger scale. Spielberger trait anxiety distinguishes corresponding to a structural component of state-trait anxiety in a situation or a specific event.
Warning :
Many definitions of attention have been proposed. Some consider attention as the ability to control the application of intellectual activity field.
We distinguish schematically diffuse attention, which is a general state of awakening of all the senses, and selective attention, which involves both the focus and mental concentration to a specific task and inhibition of competing activities. The ascending reticular activating system, the amygdala, hippocampus and frontal cortex play an important role in awakening and orientation reaction against stimulations.
Attention disorders and anxiety:
Experimental research on attention and emotion are particularly important for the development of rigorous scientific theories of emotional disorders.
The main tests used in the exploration of attentional changes induced by anxiety are the dichotic listening test (the subject focuses on one side his attention to a stimulus while another stimulus succeeds him at the same time to opposite ear) of visual and auditory lexical decision task, nonverbal tasks of visual detection (faces scenario) and the divided focus tests.
In treatment situation of neutral information, Shapiro and Lim showed that anxious subjects favor attention to the peripheral visual stimuli to the detriment of the visual system foveal devoted to strategic signal processing, while non-anxious subjects prefer a visual attentional strategy Central.
These results are consistent with a hypervigilance in anxious in connection with a hyperfunction of the warning system characteristic visual detection device.
Whatever the terms of processing of information (visual, auditory …), hypervigilance the anxiety subjects promotes distractibility and irrelevant detection in complex attentional tasks.
Attentional processing of emotional valence information shows particular sensitivity of anxiety to the capture of threatening stimuli relative to neutral stimuli, particularly in subjects with generalized anxiety disorder.
Furthermore, in all forms of anxiety, there is an attentional bias “préattentif” that privileges the threatening information even before the stimulus is processed in detail.
MEMORY AND DEPRESSION:
Splitting the memory:
Given the complexity of the phenomenon, Ebbinghaus, in 1885, proposed to split the memory over time in long-term memory and short term memory. Tulving distinguished memory depending on the content, setting one hand episodic memory, the other semantic memory.
Episodic memory is the memory system hierarchically highest and most complex. Its content is frequently connoted emotionally.
The brain regions involved in its operation include the prefrontal regions and would be more extensive than those involved in other forms of memory.
Different memory systems are set to narrow neuropsychological assessment: sensory memory corresponds to the acquisition and maintenance of the shape and structure of objects and words; procedural memory is a memory which automatically allows a subject to learn of the actions, to acquire expertise; episodic memory refers to recall of events in a particular context (autobiographical events ordained / time / place); semantic memory is linked to the knowledge system by storing general facts.
The events of the recovery modes based on memory systems described above are characterized by the terms explicit or declarative memory versus implicit memory.
The first refers to memories that require a conscious recovery of a learning episode (explicit) versus self conscious memories of a recovery (implicit).
Memory disorders and depression:
In depressed patients, the mnemonic dysfunction is positively correlated with the severity of depression. Bazin et al observed during explicit mnemonic tests both quantitative and qualitative abnormalities.
The emotional valence (neutral, positive and negative) of the material to encode explicit influences memory performance, unlike the implicit performance. Markowitsch reported research on stressful situations and dépressiogènes that cause dissociative reactions and cognitive deterioration.
Thus, qualitative distortions and / or omissions were described in the recall of traumatic events among soldiers who participated in the Gulf War.
These situations have relations with learned helplessness and lead to changes in the availability of neurotransmitters.An explanatory hypothesis of cognitive dysfunction in depressed concerns the hypothalamic-pituitary-adrenal axis in relation to a hypersecretion of cortisol. Glucocorticoids interfere on noradrenergic receptors of the hippocampus.
Studies show that depressed patients show a reduction in blood flow in different regions of the prefrontal cortex and in subcortical structures such as the amygdala.
A primary depression with cognitive impairment often known as the depression pseudodementia or dementia may be wrongly regarded as a neurodegenerative dementia.
But depressed patients differ considerably the dementia that characterizes the collapse of semantic memory and boot.
In addition, depressed patients show a significant cognitive improvement after treatment.
SCHIZOPHRENIA AND EXECUTIVE FUNCTIONS:
Frontal syndrome and executive functions:
The functions “executive”, that is to say the strategy, planning, organization, problem solving, inhibition of irrelevant strategies are one of the roles of the frontal lobes.
They are deficient in schizophrenia patients.
In schizophrenia, many cognitive and behavioral tests are disrupted.
Memory tests were used to study the temporal and septohippocampiques structures.
Traction tests indicated the functional characteristics of subcortical structures of the basal ganglia.
In this regard, the memory impairment observed in schizophrenia are interpreted by Huron and Danion in a circular causality: the deficit strategic process would result in a disruption of conscious recollection, which in turn would cause a deficit in the actuation of strategic processes.
Initial neuropsychological studies have suggested an analogy with neurological damage.
In the search Partiot et al, the performance deficit in spatial discrimination, first of schizophrenia, the other patient with a head of organic origin reached, suggesting an inability to inhibit a mental mechanism in place rather an inability to generate a new one.
The magnetic resonance imaging (MRI) has to objectify and confirm the initial results obtained by CT scan (reduction of the lateral ventricles and cortical volume). Some observations of resting brain MRI, correlated with cognitive tests have confirmed the hypothesis of a hypofrontality, especially in chronic forms of schizophrenia.
The development of brain activation tests (brain activity during the performance of an experimental task) allows use of MRI in a neuropsychological approach qu’anatomoclinique.
So Andreasen showed a decrease metabolism dorsolateral prefrontal cortex in schizophrenia, in exploration tasks frontal functions (planning, strategy). Such a deficit is not interpreted in a localizationist perspective. It is analyzed in terms of functional dysconnection between frontal brain areas and hippocampal circuits.
Outlook:
Current clinical neuropsychology is interested more and more to the relationship between the new data imaging (MRI, functional MRI, positron emission tomography) and functioning of mental activities, as well as restoration of factors and brain plasticity underlying mental functions of the brain-damaged subjects.
Cognitive neuropsychology, meanwhile, is moving towards the understanding and modeling of the normal operation from limited studies of brain damage.
Cognitive changes they cause can be inferred normal operating rules. This very fruitful approach, using unique cases, are from several models, including the Morton model the mechanisms of writing and reading, and that of the working memory Baddeley.
It is the understanding of cognitive processes themselves checked by the study of lesions that premium.
The réadaptive neuropsychology was formed several years ago, from the experience with stroke patients.
It uses both the data of traditional clinical neuropsychology and models proposed by cognitive neuropsychology. The latter mainly influenced the rehabilitation of direct cognitive disorders such as attention deficit disorder, logical reasoning and executive function.
Thus, rehabilitation methods applied to front syndromes have been structured proposals.
The first rehabilitation attempts have focused planning across the pre-organization of the task and the regulation of the activity through language.
The development of cognitive neuropsychology and application of its principles to rehabilitation have allowed the development of specific therapeutic programs.
These programs are established by the comparison of data a detailed initial clinical assessment, theoretical hypotheses about the mechanisms underlying disorders and the methods for reducing them. Moreover, behavioral and social adjustment benefited from the influence of cognitive and behavioral theories and cognitive behavioral therapies applied in different areas of pathology.
Privileged and rigorous observations have shown that neuropsychological rehabilitation was feasible, credible and effective, especially in brain-damaged subjects.
It evaluates and supports specifically cognitive deficits induced by injury or brain dysfunctions in order to improve the quality of life of subjects.
For a comprehensive approach, it considers the impact of functional or organic abnormalities on different cognitive and psycho functions to act on adaptive behaviors.