Saturday, February 28, 2009

Frontal alternating tests Luria

tap two beats, then switch to three beats

alternating square wave and triangle wave in a connected line

fist palm edge

draw 3 elements is succession to verbal instruction: circle, cross and minus sign. Maintain elements and then have a new command with a switched order of elements

Learning poetry by heart

VISUAL presentation of v oral of a series of letters, numbers, or words or figures

Testing spatial (simultaneous) synthesis and successive synthesis

Spatial= figure copying, left-right, hand postures, mental rotation
Successive- tapping rhythms, ordering 4 words or symbols, or numbers

Balint's inability to do simultaneous analysis does successive

Sorkina and Homskaya (1960) found such patients could differentiate red and green, then white and yellow, but then if presented with all 4 then respond haphazardly to signals.

Tactile loss of simultaenous synthesis (agnosia) unable to synthesize a whole pattern is described by Delay (1935) and Denny Brown (1952) and called amorphosynthesis.

Other spatial synthesis tests that may be done incorrectly include drawing the direction of an arrow, distinguish symmetrical figures, know which way to draw a line in a geometrical figure, draw letters, production of mirror writing.

Friday, February 27, 2009

Quotes interesting from, about, re Luria and colleagues

Most taken from Human Brain and Psychological Processes

Gall was " a celebrated anatomist but an equally great dreamer. On a basis of incomplete observations and speculative conclusions he considered that faculties such as love of children, respect for parents, a sense of mental elevation or a feeling of self could be localized in circumscribed areas of the cerebral cortex" p.4

JC Eccles (1951) At what point does the mind "enter the brain" and begin to "interact with it"

"there is no evidence for isolated cerebral centers" Luria p.13

"A function which was initially shared by two people and bore the character of communication between them gradually crystallized and became a means of organization of the mental life of man himself" Vygotsky 1960 cf. p23

"The human brain does not contain any ready made mental faculties. The cerebral cortex is " the organ capable of making new functional organs." Le'ontiev 1961 p. 38

Deutsch (1953) summarized by Pribham (1960) cf p. 33 "Destruction or constant electrical stimulation of the hippocampus in animals leads to considerable disturbance of balanced behavior. Animals are unable to perceive signals giving information concerning its own erroneous reactions so that these are no longer corrected. The normal regulation of behavior is thus disturbed." Aden(1959) and Holmes and Adey (1960) did experiments of ele stimof hiipocampus showing same thing.

Sechenov-- idea that visual scanning was as important to visual perception as was reflection in retina

Yarbuss (1956) An object falling on a single point of retina ceased to be visualized after 2-3 seconds and to be kept as an image for longer than that the eye has to make small movements.

Analysis of Chinese writing bypasses phonology since writing incorporates idea of words rather than the sounds. Writing in Russian has many more mistakes if child is prevented from performing inner or silent speech while writing (Nazarova, 1952).

Structure of writing also changes during stages of learning to write versus already knowing how and doing it as an overlearned process.

Sechenov--1878 Mental processes fall into 2 categories: integration of elements in simultaenous groups, and placing elements in successive series. Simultaneous groups are essential for creating an adequate image of the outside world is generally associated with the visual, kinetic and vestibular apparatuses, responsible for the orientation of the body in space. Conversely, successive stimuli is primarily associated with the motor system on the one hand, and the acoustic system on the other.

Chronologic localization in development requires perfect concrete reflection of outside world (Perception = first signal) in order for speech (verbal semantics=second signal) to develop normally.

Vygotsky: In early development,the direction of dependence of psychological activities is bottom to top (primary simple processes are the basis for more complex ones) but in late stages its top to bottom . For example, a hearing deficit in a child will result in an inability to speak whereas in an adult it will not. Moreover, a lesion of the occipital cortex in a child will not give rise to optic agnosia alone or allowed the formation of other mental activity undisturbed.

A lesion of the brain at different stages of ontogenesis may have completely different consequences. Vygotsky's principle restated p. 62 " In a lesion of a particular 'center' in early childhood, the corresponding 'higher center' in closest relationship to it is secondarily affected, whereas in the case of a similar lesion in an adult it is the dependent lower 'center' that is primarily affected and the specific relationship between the centers is laid down during development. "The theory of constant specific functions of each organ is unsound " (Vygotsky, 1960 p 381.

"The concept (of localization) leads to pessimistic conclusions that the restoration of functions is completely impossible " p. 63. However these conclusions are contrary to the facts repeatedly observed.

Inhibition of wider area is Monakow's diaschisis. Luria interpreted diaschisis as meaning inhibition of the function of neurons situated within the focus and close to it, disturbing their synaptic conduction, and as a result the morphologically intact nerve cells become inactive. Pavlov interpreted the physiologic basis in terms of the theory in terms of limiting protective inhibition, and by Soviet neurologists in investigations of functional asynapsia (Graschchenkov 1946, 1948).

Those 2 studies above, plus others (Luria 1948, Perel'man 1946, Eidinova and Vinarskaya (1959) showed beneficial effects of prostigmine, eserine and galanthamine.

Lashley (1960) regarded speech as one of the most obvious examples of serially organized cerebral activity. Chomsky used Markov chains and mathematical principles to analyze serial or syntactic structures.

Thursday, February 26, 2009

History of Neuropsychology

Benton AR. Neuropsychology Past present and future

Old terms

psychoneurology Bekhterev

brain pathology Kleist

enteroid processes-- old term for gyri of brain till 1820'a

Nemesius-- sensation and perception in anterior ventricles, thinking and reasoning in third ventricle and memory in fourth v (400 AD).

Antonio Guanerio (15th century) - anomia is due to phlegm in fourth v.

Thomas Willis sensation is in corpus striatum , perceptual integration in callosum and memory is in cortex.

Peyronie-- callosum is seat of intellect

Jackson 1878-- to locate the lesions which destroys speech and to locate speech are two different things

Head 1926 =the processes which underlie an act of speech run through the nervous system like a prairie fire from bush to bush.

Brissaud 1897 compared aphasie d'intonation with aphasie d'articulation

Goldstein- related amnesic and conduction aphasia to "abstract attitude"

Kleist- differentiated speech sound deafness and speech meaning deafness (1923-4)

Teuber responsible for term neuropsychology using it in 1948.

Wednesday, February 25, 2009

Luria on Thinking

c13 p. 323 Working Brain

Luria engages in historic analysis of constructs and concludes that thinking, ought to be considered as a complex act with component parts, and then it can be considered. Word meaning, the basis of ideas, develops in childhood and gradually becomes abstracted.

Luria states "psychologists are unanimous" that thinking arises when a subject arises for which he has no ready made inborn or habitual solution. Then, thought requires, successively, the restraining of impulsive responses, investigation of the conditions of the problem, analysis of its components, recognition of their most essential features and correlations with each other. Finally is the selection of one from alternative and the creation of a scheme for the performance of a task, or strategy formation. Finally is the choice of methods and operations to put the scheme into effect, the tactics of the solution. The last step is actually the comparison of the results with the original conditions of the task.

Luria on speech, words, repetition, naming m psychology of

C 12 Working Brain p 307 (random notes)
A word is not an association of an image of an object and a conditioned acoustic complex, but a matrix of multiple cues and connections (semantic, lexical, morphological and acoustic) and in different states any of them could be predominant.
Luria divides speech into expressive and impressive (=receptive). Expressive speech starts with an idea, is coded into a speech scheme, is formulated into operation with "internal speech," and is converted into narrative using rules of grammar. Impressive speech takes incoming speech, decodes it, puts into a speech scheme using internal speech, then into a general idea, and then into a motive. Luria emphasized that speech is also a tool for intellectual activity and a means for regulating or organizing human mental processes. The final step of analysis of expressive speech is to form decisions, draw conclusions, abstract, generalize, and think categorically.
The phasic or acoustic aspect of decoding speech involves an acoustical analysis and reduction into phonemes, and necessary articulatory cues, and articulemes, the fundamental speech unit. Then is the lexical-semantic organization of the speech act with morphologic, semantic or otherwise organized groups. After words the sentence is of varying compexity and has narrative speech, which is a transition of thought to speech (cites Vygotsky, 1936).
Receptive speech occurs with first, decoding phonemes in the temporal cortex. They connect strongly to the postcentral and premotor zones and are thus "adapted for the isolation and identification of the fundamental phonemic characteristics." He differs from Wernicke, who had postulated this step as using the temporal lobe for having "sensory images of words." A lesion here causes "acoustico-gnostic aphasia." Luria speculates but does not draw conclusions on a form of aphasia analagous to Lissauer's associative agnosia, in which the phonemic composition is intact, but the recognition of its meaning is not-- that disorder may have to do with speech/visual analyzers and will be dealt with in a subsequent 1972 publication.
Next is comprehension of a whole phrase or speech expression. This depends on retention of all elements of the speech in the speech memory (analagous to a buffer??) . Otherwise various parts of speech will mutually inhibit each other and only part of the speech can be analysed. Second it depends on simulatenous synthesis of all its elements, and the ability to survey it and place it into a logical scheme. This is essential to understanding speech constructions incorporating complex logicogrammatical relationships, with the aid of case endings, words order and inflections, and prepositions, "which Svedelius called the communication of relationships." Luria emphasizes the role of parietooccipital areas as being important in these quaispatial analyses. Third and most important is the ability to actively analyse its most important elements. This requires searching behavior, intention (ie frontal lobes) formation of a program and checking/monitoring.

p. 314
requires 1) auditory perception 2) precise system of articulation (intact lower postcentral gyrus) disintegration of which causes afferent motor aphasia, or disintegration of articulemes, to be differentiated from efferent motor aphasia or Broca's aphasia 3) ability to switch from one articuleme to another or one word to another (inferior premotor cortex is key) 4) The subordination of articulation to programs, and inhibition of irrelevant alternatives. The frontal lobes are key. They must monitor and regulate. Patients may be unable to reproduce nonsense speech. Luria refers us to (in press) Towards the revision of conduction aphasia.

Naming objects p. 316
requires 1) visual perception which if degraded leads to optic aphasia (se Tsvetkova, 1972 (Russian)). 2) precise acoustic structure of speech connected with speech hearing system of left temporal cortex. Damage leads to literal paraphasias, absence of help of prompting. 3) Most important, discovery of the proper selective meaning and the inhibition of irrelevant alternatives. In pathologic states when "law of strength" is not obeyed is most susceptible. 4) Mobility of nervous processes eg. if a name is found, its not frozen, can switch to another name etc. (Left premotor area is key).

Transition to linear scheme of sentence
impaired with postcentral gyrus lesions. Interesting patients who could not do, had no emg of lips and tongue, until external aids were used, when they did have. This is a rehabv strategy-- use pieces of paper in fragments and organize them into a narrative.

Luria describes the inability to use prepositions as transcortical motor aphasia patients can repeat words but not articulate phrases or preserve spontanous speech.

Luria on Memory

Working Brain c 11 p 280

Luria laments the lack of effective work on memory processes up to 1960 or so when RNA was linked to memory. Specifically RNA traces remain high in glia for a long time after learning. Luria asks which brain zones contribute to memory, what are the architectonics of memory, and what is the structure of mnestic activity.

Luria cites literature (p283) that learning starts with the imprinting of sensory cues (eg. phonetic). Imprinting is selective, narrow in scope, and short, may be expandable in case of visual memory. The next intermediate step is the conversion of images to a a storable code or category. They are coded with respect to different signs and form multidimensional matrices from which the subject must choose. The process for retrieval is active, not passive. The subject uses language, that helps transfer from short to long term memory (cites Miller, 1969). He then asks what causes forgetting? Mere extinction or decay of traces is countered by idea of "reminiscences" which involve the enhancement of the traces. Then the ideas of proactive and retroactive inhibition became accepted as ideas, the idea being that forgetting is largely the regulator function of irrelevant, interfering actions that inhibit normal recall of traces. Luria cites Soviets Vygotsky and Le'ontiev as noting that recall is usually indirect and accomplished throught the use of "aids." Le'ontiev described it with respect to children's development. Motives and tasks direct what is to be recalled, and coding and categorizations increase the amount that can be recalled. Memory (optimized) requires optimal cortical tone, or vigilance, and intention, and integrity of the highest secondary or tertiary zones.

Which brain zones? Bekhterev (1900, hippocampus) and Grunthal (1939, mammillary bodies) preceded Scoville and Milner. Luria states the hippocampus is a modality independent structure of the archicortex that modulates cortical tone but compare stimuli to traces of past experience, react to changed stimuli and are therefore both "attention" and "memory"
neurons. Luria repeats that patients with pituitary tumors affecting these zones have mild memory disorders. Hippocampal memory disorders are characterized by modality nonspecificity, by primary defect of trace retention (and ability sometimes to compensate by writing down), and disturbances of consciousness.

Experimentally, subjects can repeat 5-6 words and retain it for 1-2 minutes unless there is interfering activity. Luria concludes pathological increased mutual inhibition of traces is the basic physiological factor in primary disturbance of memory observed in deep brain lesions.

Tests" Haptic fixed set illusion -- a patient with a memory disorder is given a large ball to touch with his right hand, and a small ball with his left hand, then given two balls of equal size so the one on the left appears large (fixed set illusion). Interference erases the traces of the illusion. Similarly, if an object is given and then a second object given for comparison, interference will prevent identification of same or different.

Modality specific memory loss
temporal lobe leads to acoustico-mnestic aphasia. Again Luria attributes this to increased inhibition of traces, or emergence of strong and weak traces without selection. He also calls this the "levelling of excitation of the traces."
Frontal lobes again leads to disturbance of intentions, plans, programs, and regulation. The patients are unable to use "aids" to memorize.

Tuesday, February 24, 2009

Luria on attention

c. 10 Working Brain p. 256
Begins with a discussion of old papers, including Rubin (Gestalt school) who argued attention does not exist, and idealists (Wundt, Revault d'allones) who describe it as the subject's set or "creative activity" at the other pole.

He then refers to Vygotsky and to the intense biological attentional factors present early in life between a child and mother. The child turns the eyes and the head towards the stimulus, ceases irrelevant activity, and has autonomic and GSR responses which Bekhterev called the concentration reaction and Pavlov the orienting reflex. These are observed in the first few weeks of life, first with the fixation on an external object, then with an active search for it. Luria cites research that infants will cease sucking in response to photic stimulation. Later there is inhibition of the alpha rhythm and strengthening of the evoked potentials. Sokolov and Vinogradova described many features of it. Orienting reflex is directive and selective; after extinction to an acoustic stimulus, OR still occurs to other auditory stimuli. Orienting reflex occurs on any mismatch beween neuronal model and the new stimulus.

Luria then differentiates voluntary attention and OR. The former is not biological but a social act. They are not the product of the biological maturation of the organism, but of forms of activity created in the child in his relations with adults, into the organization of complex regulation of cerebral activity. The mother names the object, the child attends to the object, learns to name it himself, and it now is part of his internal organization of psychological process. Thus Vygotsky's differentiation between elementary and higher forms of attention and its social nature is key.

Vygotsky points out that in young children, involuntary attention competes with voluntary attention, and not till age 4 can the child suppress an involuntary OR to a spoken directive to attend to a different object, eg. Internal voluntary attention is then subordinated not only to adults but also to the child's own inner speech. He cites research by Homskaya that children given a sorting task have higher accuracy when allowed to sort by speech.

Luria then cites EP literature that EP show strengthening with OR, but lasting changes only with spoken instructions.

Luria believes the hippocampus and the caudate nucleus contain the internal maps for comparison that generate the OR. A lesion of them causes a breakdown in selective attention more than memory.

Luria on frontal lobes

Working brain, p. 250
Frontal lobes maintain and control the general tone of the cortex, but with the aid of internal speech and under the influence of afferent inpulses reaching them from other parts of the cortex, formulates the intention or motor task, ensures its preservation and also its regulatory role, enables the performance of the action programme, and keeps a constant watch over its course.

Damage causes replacement of action programs with direct reactions arising uncontrollably to any stimulus, assuming the character of unsuppressed orienting reactions or echopraxia, the eruption of inert stereotypes, and with massive lesions the comparing role that allows awareness of mistakes and the ability to check the course of action.

The premotor zones the important cerebral apparatus for 'kinetic melodies' or series of skilled movements.

Mutual coordination of the hands occurswith anterior corpus callosum and lesions thereof leave each hand able to perform a task , but the two hands together unable to perform mutually coordinated movements.

Luria on perception

Isomorphism, as introduced by the Gestalts such as Kohler, believe that during perception, a passive imprint on the retina is then transmitted to the cortex. More recent views of perception regard it as an active, complex process, involving perception, analysis, coding, synthesis, active inspection.

Luria notes a visual image stays on the retina for 1.5 seconds, with an afterimage lasting about 20 seconds (Working Brain p. 232). In patients with damaged occipital areas, the after image lasts a shorter time, but is longer with administration to caffeine (cites Zislina 1955). Thus the visual cortex not only synthesizes elements but also stabilizes them, similar to the temporal lobe after injury with respect to auditory elements.

Associative visual blindness (associative visual agnosia) as opposed to apperceptive agnosia is intact perception, abnormal recognition.

Luria: frontal lobes and memory

Working brain 210-225.
Patients' actual memories are preserved, but ability to create stable motives, active effort, ability to switch from one trace to another is not preserved. List learning shows an early plateau.

Clinical tests
thematic picture-- will focus on one element and stop. (eg p215 picture of man falling through ice). Picture Unexpected Return p218. Eye movements show absent scanning. Arithmetic-- trouble with serial 7's or 13's; trouble with alternating operations (plus then minus). Only partially effective treatment is dividing into consecutive questions with external supports for each one.

jackson-- Frontal lobes not only are the most recent and largest part of the brain, but the least organized. Lesions can be compensated for or appear asymptomatic. However, Luria divides frontal lobes into the lateral zones, which cause disintegration of motor and in left sided lesions, of speech activity. The medial basal frontal lobes connect to reticular formation and the limbic brain. Luria notes potential effects on olfactory structures, generalized disinhibition and gross changes in affective processes. Impulsiveness and fragmentation occur preventing many tasks.
Some of the terms used by Luria for medial zone lesions include the "oneroid state," diminihsed critical faculty, disturbance of action acceptor apparatus, disturbance of selectivity of mental actions, disturbance of memory and confabulations.

Frontal Lobes and Regulation of Motor Activity

Luria The working Brain c. 7 p. 187
Luria considers these tertiary zones for the limbic and motor systems and crucial for regulating vigilance and goal linked activity. "expectancy waves" in the frontal lobe precede activity. Speech has an "activating role" which formulates the problem. This increase in cortical tone from the activation role of speech is deficient in patients with frontal lobe lesions (cites numerous publications on which Homskaya is listed as an author). Autonomic changes due to an orienting reflex continue until habituation, interruption or completion of the task. Autonomic components of the orienting reflect evoked by spoken instruction continue after posterior but not anterior lesions. Luria concludes p. 189 "the frontal lobes participate in the regulation of the activation processes lying at the basis of voluntary attention."

Electrophysiologically, the EEG depression of alpha rhythm occurs in response to any spoken instructions but are absent or unstable in patients with frontal lesions, but is preserved in those with posterior lesions. Analagous findings occur with evoked potentials and frontal and posterior lesions.

Luria emphasized that the apathoakineticoabulic syndrome of massive frontal dysfunction does not affect all behavior, just higher cortical function. Orienting reactions to irrelevant stimuli, not intention based, are not only undisturbed but may be intensified. Patients do not reply to questions, make requests, or complete tasks but will lok at door that squeaks to see who is coming in. They may join physician's conversation with a neighbor, even if they won't ask questions directly posed to themselves. Luria concludes that massive injuries to the frontal lobes control only the most complex forms of regulation of conscious activity and in particular, acitivity controlled by motives formulated with the aid of speech (Luria, 1966 a,b 1969 a,b).

Effect of spoken instructions is complex, patients may cease to obey gradually, or repeat and not do command. He may also replace it with an inert stereotype eg. putting a match in his mouth and attempting to smoke it. (note- comparable to apraxic content error). {atient's own speech is also not enough to regulate. If asked to tap, rhythmically, strong, weak, weak, saying is not enough to make patient do it.

Clinical tests for-- echopraxia, usually performed correctly. Different forms of contrasting programs motor task (if I make a fist, you raise your finger). (tap once if I tap twice, tap twice if I tap once). Homskaya (1966) and Maruszewski (1966) show that patients lapse into echopraxia after a short amount of time. Luria's idea, is that each attempt to follow a spoken command leads to a "flood of inert stereotypes." Drawing may be performed correctly on first attempt (circle, square, cross) but changing leads to perseveration. Patients also lose the ability to self monitor results and change if needed. In spite, they recall the task. However, they can monitor the same tasks as OTHERS perform them and notice others' mistakes. (numerous citations p 210 Working Brain)

Monday, February 23, 2009

Luria on nondominant parietal lobe

The Working Brain p, 160

Luria notes the absence of acalculia but the presence of unawareness of the left visual field in patients with a field defect (unlike left hemisphere lesions). Its also true in spontaneous construction and drawing . Cites Korchazinskaya, 1971 (Unilateral spatial agnosia in brain lesions, dissertation, Moscow). Luria also notes anosognosia, inability to notice and correct mistakes, in patients with right hemisphere (parietal) lesions.

He also discusses the lack of familiarity with known objects or faces, despite intact perception, such as in prosopagnosia. He calls it a paragnosia --replacement of a direct correct perception of an object by uncontrollable guesses about its nature. Constructional apraxia and representations of external space are much more common than in left sided lesions.

Luria cites Sperry's split brain model as evidence that the right hemisphere can neither participate in any extent in speech function or in complex motor acts. Logical reasoning and logical grammatical structures are not affected. However, Luria cites Teuber as evidence that the right hemisphere is less differentiated than the left. For example, sensory agnosia localizes much more sharply in the left hemisphere than the right. In the right hemisphere, disorders are more likely polymodal and polysensory. Problems of the "body schema" are more common in the right hemisphere, including a sense of disproportionality of particular body parts. The right hemisphere does participate in direct visual perceptions and direct visual relationships with the world (Hughlings Jackson, 1874). Dressing apraxia refers to right hemisphere about 80 percent of the time.

Anosognosia,or lack of awareness of deficit (such as hemiplegia) is explained by lack of awareness of deficits not related to speech mechanisms (p. 168).

Disorders of personality and consciousness may include confusion, and disorientation, and subterfuge through humor or speech to hide or disguise the deficit. Lack of logical operation allowed such patients to believe they were in two different places at the same time, without a contradiction in the statement.

Luria hints at a role for the right hemisphere in consciousness, which he will address in a series of papers being prepared for publication.

Luria on amnestic aphasia

The Working Brain p. 156
goes with " speech memory" and anomia. Luria states that outwardly these patients with parietal lesions resemble those with middle temporal gyrus anomia, but features are different than with audioverbal memory disorder. Instability of the acoustic basis of speech is not present, as patients clearly benefit from prompting with the first sound or syllable (phonemic priming). Every word is a code, or part of a classification or system of values. Since semantic schemes are disturbed, naming is abnormal. In affected or damaged cortex, the "law of strength" is disturbed and weak stimuli evoke similar responses as strong stimuli. A "flood of equally probable possibilities prevents the discovery of the required dominant word." (Luria 1972 Aphasia reconsidered, Cortex 1:1). So paraphasias are common. Tsvetkova (1972) noted the naming problem affects objects not actions. This study was based on reaction time to name qualities, actions, objects . In particular concrete objects are affected. Further , Tsvetkova found that visual representations of the objects were abnormal and drawings or descriptions showed unexpected defects.

Luria: Parietal lobes and complex simultaneous spatial synthesis

c5 p. 147 Luria The Working Brain

Luria notes this part of the brain is entirely human. It maintains connections with the thalamus and is a supramodal analyser. This is known by electrical stimulation and lesion studies that show no modally specific effects.

Luria compares lesions to those of simultaenous agnosia with an inability to fit together individual elements into a whole, or convert presentation of consecutive elementsinto simultaneous perceptibility. However, in addition, they cannot find their bearings within a system of spatial coordinates especially being able to tell right and left.

Patients get lost, cannot find their bed, cannot tell time from hands of a clock without numbers, find their bearings on a map, tell east from west, reproduce the position of the hand. They cannot draw letters due to inability to retain the required spatial position of the lines of the letters. Patients may write/draw mirror images. Severest form manifests in inability to directly reproduce 3D structures. Less severe forms include inability to reproduce spatial forms from memory. Other tasks are mirror reversal tasks. Constructional apraxia can occur.

Luria states that classical Gerstmann's syndrome ( acalculia, right-left confusion, finger agnosia, central alexia) has deeper roots with more symptoms. Complex logico-grammatical structures may be poorly understood, particularly with embedded constructions, passive actors and objects or sentences with the requirement of understanding the grammatical or spatial relationships among multiple actors.

The syntagmas, or syntactic structures expressing logical relationships is a term credited to the Swedish linguist Svedelius (1897). Communications of relationships occurred late in the evolution of languages, within the previous hundred(s) of years with the aid of inflections, prepositions or word order. All coded logical not concrete relationships, for example, the attributive genitive, "the father's brother." Although others called the inability to understand these relationships "semantic aphasia," Luria considers it a problem of spatial structures transferred to a higher symbolic level and affecting language.

Luria attributes acalculia to the use of internal spatial schemes such as tables, which are dependent for simultaneous synthesis and spatial operations, such as columns, to do arithmetic operations, and the need for right-left orientation to place the remainders in the correct position. Patients are aware of their inability to do complex operations, but are otherwise "intact" for motive, and otherwise.

Luria on temporal cortex

Destruction of temporal cortex does not cause loss of hearing, but does cause loss of differentiation of combinations of sounds (numerous citations, working brain p. 131). This was also true even with very small lesions. Semernitskaya (1945) noted ability to discern simple sounds but not to repeat series of taps or rhythms, nor to identify same.

Luria discusses the "phonemic system" of language (p134) in which some characteristics of sounds are crucial in one language and unimportant in another; in order to distinguish these sounds of speech in any language it is necessary to code them according to the system, pick out the useful characteristics and to separate them from unimportant features known as variants. He cites Trubezkoi and Jakobson as writing laws about the perception of sounds of speech.

Luria equates "acoustic agnosia" and "sensory aphasia" and believes disturbance of audioverbal memory is closely related. Further he describes "increased mutual inhibition" of auditory traces, a characteristic defect of the pathological state in the temporal cortex." Presenting acoustic stimuli at longer intervals decreases inhibition and thereby decreases errors. Cites unpublished work of Tsvetkova, and of Luria, Sokolov and Klimkovsky (1967) (Neuropsychologia).

Luria attributes the naming defect to difficulty with phonemic imprecision the inability "to profit from the prompting at the beginning of the word." Speech disorder (up to "word salad") as due to some words being phonemically defective, others with wrong word choice, with an unawareness of errors and inability to self correct. An inability to write is similarly due to phonemic frustration at finding required sounds and letters. On the other hand, the ability to write a signature, which is really a motor automatism, is a "clear example of a change in structure and cerebral organization of a process in the course of functional development" (Luria et al. , 1970, Neuropsychologia). He notes the ability of some people to copy sentences but not to write to dictation.

Speech hearing deficits do not imply by any stretch deficit in musical hearing.. Luria has a famous case report of a musician who was aphasic but still performed. Similarly, melodic and intonational aspects of speech are not impaired.

Simultagnosia from The Working Brain by Luria

Pavlov explained simultaneous agnosiaby saying the cells were "so weakened" that one excited point exerts an inhibitory effect on the other excited point, thus making it apparently nonexistent (Pavlov IP, Pavlov's Wednesday Clinics, vols 1-3, Izd. Akad. Nauk SSSR, Moscow and Leningrad, 1949 (Russian) as cited p. 123. Cites Pribham as saying defect is due to corticofugal projections to inferior temporal lobe.

Luria then took a subject affected with a bullet wound, injected caffeine 0.05 ml of 1 % solution, , with the result that the patient could see two and sometimes three objects for 30-40 minutes (as long as the caffeine lasted) and the visual ataxia disappeared.

Examination of the patient:

cf p.117
Patients obscure pictures. May require tachistoscope to bring out changes with brief exposures if mild case. Defect involves not only perception but also drawing.
Tests-- cannot place a dot in the center of a circle or a cross/ cannot draw a triangle around a triangle.

The "secondary zones" of the left occipital cortex differ from the right insofar as they "retain their intimate connection with speech" unlike the right. Lesions of the left cause an agnosia for letters or reading (optic alexia). In right hemisphere agnosia for objects or faces is more common.

Sunday, February 22, 2009

Differences in brain function as child develops

Working Brain p. 32 Basic perception early

"The yong child thinks in terms of visual forms of perception and memory and thinks by recollecting. At later stages or in adult life, the aid of the functions of abstraction and generalization is so highly developed that even relatively simple processes such as perception and memory are converted into complex forms of logical analysis and synthesis, and the person actually begins to perceive or recollect by reflection."

In "dynamic" Soviet neuropsychology, a lesion of "elementary" cortex such as visual cortex early in life produces more profound changes than later in life because it will affect the "higher areas" above development if it occurs early.

Revision of the concept of "symptom" p. 34

"In order to progress from the establishment of a symptom (loss of a given function) to the localization of a given activity, a long road has to be travelled...the detailed psychological analysis of the structure of the disturbance and the elucidation of the immediate causes of the collapse of the functional system or in other words, a detailed qualification of the symptom observed."

Friday, February 20, 2009

Thw Working Brain function and localization

AR Luria (1973)

Preface-- "Are man's gnostic processes and motivated actions the result of the work of the whole brain as a single entity, or is 'the working brain' in fact a complex functional system embracing different levels and different components each making its own contribution to the final structure of mental activity." (p.11).

Seld criticizes in advances lack of data on "minor hemisphere" and medial corticobasal structures.

Chapter one cites Broca's postulate based on his cases that the "posterior third of the left inferior frontal gyrus is the 'centre for the motor images of words' identifying the left hemisphere in righthanders as the dominant hemisphere for language. Cites Wernicke that the posterior third of the STG is 'the centre for the sensory images of words' or the 'centre for understanding of speech ' (Wortbegriff). In the "splendid 70's" ie 1870's, and for a half century, there was an attempt to "localize complex psychological processes in local areas of the brain" p.23. However, Luria state (p.25) that "without denying the obvious fact that elementary physiological 'functions' (such as cutaneous sensation, vision, hearing, movement) are represented in clearly defined areas of the cortex, these investigators [Monakow (1914), Head (1926), Goldstein (1927, 1944, 1948)]expressed valid doubts about the applicability of this principle of 'narrow localization' to the brain mechanisms of complex forms of mental activity.

"They therefore postulated that the complex character of "semantics" (Monakow) or "categorical behavior " (Goldstein) are the result of activity of the whole brain rather than the product of the work of local areas of the cerebral cortex... dependent more on the mass of the brain involved than on participation of specific zones of the cerebral cortex (Goldstein, 1944, 1948). ... (Luria then refers to) the decisive role of mass in the performance of mental activity, which have repeatedly burst forth throughout the history of the study of brain as the organ of mind." (cites Flourens, 1824, Goltz 1876-84, Lashley, 1929).

p.27 Reexamination of the concept of 'function'
"Those investigators who have examined the problem of the cortical 'localization' of elementary function by stimulating or excluding local brain areas have understood the term 'function' to mean the function of a particular tissue... when we speak of the function of digestion or the function of respiration it is abundantly clear that this cannot be understood as the function of a particular tissue..the whole of this process is carried out, not as a simple function but as a complete functional system, involving many components belonging to many different levels of the secretory, motor and nervous apparatus. Such a functional system (the term introduced and developed by Anokhin, 1930, 1940, 1949, 1963, 1968a, 1972) differs not only in the complexity of its structure, but also in the mobility of its component parts... for example,(in respiration) if the diaphragm ceases to act, the intercostal muscles are brought into play... THE CONCEPT OF 'FUNCTION' AS A WHOLE FUNCTIONAL SYSTEM IS A SECOND DEFINITION DIFFERING SHARPLY FROM THE DEFINITION OF A FUNCTION AS THE FUNCTION OF A PARTICULAR TISSUE. WHEREAS THE MOST COMPLEX AYTONOMIC AND SOMATIC PROCESSES ARE ORGANIZED AS 'FUNCTIONAL SYSTEMS' OF THIS TYPE, THIS CONCEPT CAN BE APPLIED ON EVEN STRONGER GROUNDS TO THE COMPLEX 'FUNCTIONS' OF BEHAVIOR." Further cites movement, example of Bernshtein, and Lashley mouse removed cerebellum and mouse achieved motor goals by different task, going head over heels.

p.30 Revision of the concept of localization
again, respiration "Pavlov, when discussing the notion of a respiratory centre, was compelled to recognize that 'whereas at the beginning we thought this was something the size of a pinhead in the medulla, now it has proved to be extremely elusive, climbing up into the brain and down into the spinal cord, and at present nobody can draw its boundaries accurately."

"The higher forms of mental processes have a particularly complex structure; they are laid down in ontogeny. Initially they consist of a complete, expanded series of manipulative movements which gradually have become condensed and have acquired the character of inner mental actions (cites Vygotsky 1956, 1960, Galperin 1959). As a rule, they are based on an external system of aids, such as language, the digital system of counting, formed in the process of social history, they are mediated by them, and cannot in general be conceived without their participation (Vygotsky); they are always connected with this reflection of the outside world."

"Two facts sharply distinguish the human brain (p31)... higher forms of conscious activity are based on certain external mechanisms (good examples are the knot we tie in our handkerchief so as to remember something essential, a combination of letters we write so as not to forget an idea, or a multiplication table) these external aids or historically formed devices are essential elements in the establishment of functional connections between the individual parts of the brain, and that by their aid, areas of the brain which previously were independent become the components of a new functional system. THIS CAN BE EXPRESSED MORE VIVIDLY BY SAYING THAT HISTORICALLY FORMED MEASURES FOR THE ORGANIZATION OF HUMAN BEHAVIOR TIE NEW KNOTS IN THE ACTIVITY OF MAN'S BRAIN, AND IT IS THE PRESENCE OF THESE FUNCTIONAL KNOTS, OR , AS SOME PEOPLE CALL THEM, NEW FUNCTIONAL ORGANS (cites Leonti'ev 1959)...

"The second distinguishing feature of the localization of higher mental processes in the human cortex is that it is never static or constant, but moves about essentially during development of the child and at subsequent stages of training... any complex activity is at first expanded in character and requires a number of external aids for its performance, and only later does it gradually become condensed and converted into an automatic motor skill.

(For example, in writing) the initial stages require the memorization of the graphic form of every letter, through a chain of isolated muscle impulses, each of which is responsible for one element of the graphic structure... with practice, the structure is radically altered and writing is converted into a single kinetic melody... In the course, it is not only the functional structure of the process which is changed, but also naturally, its cerebral organization." The participation of the auditory and visual areas of the cortex, essential early, is no longer necessary in its later stages, and the activity starts to depend on a different system of concertedly working zones (cites Luria, Smernitskaya, and Tubylevich, 1970).