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Historical Notes on Reorganization of Function and Neuroplasticity

Historical Notes on Reorganization of Function and Neuroplasticity. History has been filled with philosophers, men and women of medicine and science that have all been intrigued by the workings of the brain… BUT has anyone really figured it out?. SPONTANEOUS RECOVERY.

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Historical Notes on Reorganization of Function and Neuroplasticity

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  1. Historical Notes on Reorganization of Function and Neuroplasticity History has been filled with philosophers, men and women of medicine and science that have all been intrigued by the workings of the brain… BUT has anyone really figured it out?.....

  2. SPONTANEOUS RECOVERY • IN EARLY HISTORY DISEASE WAS THOUGHT TO BE A RESULT OF NATURAL OR SUPERNATURAL FORCES • AS TIME WENT ON THE BELIEF THAT IT WAS THE FORCES OF NATURE ALONE THAT WERE RESONSIBLE FOR SPONTANEOUS RECOVERY • “NATURE ITSELF FINDS A WAY, THOUGH UNTAUGHT AND UNINSTRUCTED - IT DOES WHATS PROPER” • ~EPIDEMICS VI,5

  3. NATURE OF DISEASE AND RECOVERY • DURING THE EVOLUTION OF NEUROSCIENCE, THE IDEA THAT NATURE (INTERNAL NATURE OF THE BODY) BECAME ACCEPTED AND WAS DISSEMINATED AND INTERPREDED BY PROMINENT FIGURES IN MEDICINE DURING THE 19TH CENTURY

  4. P. FLUERNS • EARLIY IN THE 19TH CENTURY PIERRE FLUERENS, A FRENCH PHYSIOLOGIST, ASSERTED THAT LOBES ACT AS A WHOLE WITH NO SPECIALIZATION OF FUNCTION • FLUERENS BELIEFS WERE BASED ON ABLATION EXPERIMENTS WITH PIGEONS

  5. FLEURENS con’t LOBES AS A WHOLE: NO SPECIALIZATION • When lobes are completely removed= all capabilities lost • Partial ablation that removed nearly all of the lobe= impairment, but not entire loss of capabilities • Small removals in any of the lobes= complete return of capabilities

  6. SIZE DOES MATTER!(GET YOUR MIND OUT OF THE GUTTER ) • FLEURENS SUPPORTED THE IDEA OF REDUNDANCY AS A FACTOR AFTER PARTIAL ABLATIONS • FLEURENS ALSO BELIEVED THAT THE SIZE OF THE LESION DICTATES THE AMOUNT OF FUNCTIONAL RESTORATION

  7. LOCALIZED OR ANTILOCALIZED? • OPPOSED TO FLEURENS WAS JOSEPH GALL • GALL BELIVED THAT THE BRAIN ACTUALLY HAD 27 ABILITIES AND PERSONALITES THAT COULD BE MAPPED ONTO SPECIFIC AREAS ON THE CEREBRAL CORTEX

  8. BROCA AND FRITCH/HIZIG BROCA’S LOCALIZED SPEECH IN THE LEFT HEMISPHERE IN THE 1980’S FRITCH AND HITZIG’S DEMONSTRATED THE EXCITABILITY OF THE MOTOR CORTEX IN THE 1870’S *THIS LAID TO REST THE BATTLE IN FAVOR OF LOCALIZATION*

  9. CEREBRAL CONNECTIONS • THESE DISCOVERIES ALL LEAD TO SIGNIFICANT ADVANCES IN THE DEVELOPMENT OF THE NEURO CONCENTRATIONS AND PATHWAYS IN THE HUMAN CEREBRAL CORTEX • THESE DEVELOMENTS WERE GENERALY FOCUSED ON THE SUBSTRATES OF PERCEPTION, MOVEMENT,SENSATION, AND SPEECH • FURTHER ADVANCES FACILITATED UNDERSTANDING OF THE CONCEPT OF STABLE CONNECTIONS OF AFFERENT AND EFFORENT PROCESES

  10. NEURAL NETWORKS ADVANCES ALSO TOOKPLACE IN DILINEATING NEURL NETWORKS IN PATIENTS WITH VISUAL DEFECTS HEMIPARESIS, AND BROCA AND WERNICHE APHASIA WHICH CORRESPONDS TO DEFINED COTICAL AREAS OR PROXIMAL CONNECTIONS

  11. RECOVERY? AS CLINICAL NEUROLOGY AND SURGERY GAINED CREDIT AS A TRUE MEDICAL SPECIALTY, AN AREA OF QUESTION AROSE: HOW CAN IT BE EXPLAINED THAT AFTER A DEFECT OR INJURY THERE CAN BE COMPLETE RECOVERY OF FUNCTION TO THE PROCESS ATTRIBUTED TO THE AFFECTED AREA?

  12. REORGANIZATION • REDUNDANCY COULD NOT ALONE EXPLAIN THIS PHENOMENOM • REORGANIZATION BECAME THE NEW CONCEPT OF FOCUS • IT WAS DISCOVERED THAT ONE AREA OF THE BRAIN WOULD ASSUME RESPONSIBILIY FOR THE DAMAGED AREA THE BRAIN HAS PLASICITY

  13. WIRED BUT CHANGEABLE • WHILE WE ARE WIRED TO DEVELOP SPEECH IN THE LEFT HEMESPHERE, WE ARE NOT SOLELY TIED TO THE LEFT SIDE OF THE BRAIN • DISEASE OR INJURY TO THIS PORTION OF THE BRAIN DESIGNATED FOR SPEECH DOES NOT MEAN ASSURED APHASIA.

  14. REORGANIZATION • ACCORDING TO COTARD, OUR BRAINS ARE ABLE TO REORGANIZE WHEN MET WITH DAMAGE OR UNDERDEVELOPMENT -NEURO CONNECTINS ARE ABLE TO CHANGE! -THESE CONNECTIONS HAVE PLASTICITY • COTARD ALSO ASSERTED THAT YOUNGER MINDS ARE BETTER AT REORGANIZING TO COMENSATE FOR “BAD WIRING” • SOLTMAN, A FEW YEARS LATER, SUPPORTRD WITH THIS IDEA THROUGH TESTS RAN IN PUPPIES WITH HEMISPHERIC ABLATIONS. -HE FOUND THAT ABLATIONS AT THIS STAGE OF MATURATION, LESIONS MADE RESULTED IN NO DETECTABLE DIFFERENCES IN BEHAVIOR OR THE ANIMAL THEREFORE, THE DEVELOPMENTAL TIMING OF LESION IMPACT THE EXTENT OF LOSS OR RENTENSION OF FUNCTION

  15. JACKSON IN THE 1870’S, HUGHLING JACKSON FOCUSED ON THE RATE OF THE DEVELOPMENT OF A LESION *RAPIDLY DEVELOPING LESIONS (STROKE): INCREASED SYMPTOMOLOGY *SLOWER DEVELOPING LESIONS (TUMORS): LESS SYMPTOMOLOGY *MOMENTUM ALSO AFFECTED RECOVERY TIME AS WELL

  16. DIASCHESIS • VAN MANAKOV EXPANDED ON JACKSON’S “MOMENTUM” CONCEPT BY STATING THAT THE EFFECT OF TRUAMA AND RESULTING DISRUPTIVNESS OF THE MAIN LESION ALSO DISRUPTS THE SUROUNDING AREA OF THE LESION THAT ARE ASSOCIATED STRUCTURALLY AND FUNCTIONALLY TO THE DAMAGED AREA • VAN MANAKOV CALLED THIS DIASCHESIS

  17. HIERARCHY OF PLASTICITY JACKSON’S SUPPORT OF NEURAL PLASTICITY LEAD HIM TO DEVELOP A HIERARCHY OF THE CONCEPT OF THE NERVOUS SYSTEM AFFERENT AND EFFERIENT FUNCTIONS ARE REPRESENTED IN THE BRAIN ON DIFFERENT LEVELS *LESIONS AT HIGHER LEVELS: PRODUCE LITTLE OR NO IMPAIRMENT *SAME LESION AT A DEEPER LEVEL: PRODUCES DIFCIENCIES BEHAVIOR CAPACITY OF A BRAIN LESIONED PATIENT WERE MORE AN EXPRESSION OF PROPERTIES OF THE REMAINING NONLESIONED AREA

  18. SUMMARY OF EARLY STUDIES ALL OTHER EARLY STUDIES REITERATED THE FINDINGS OF STOLTMANN AND JACKSON 1 THE BRAIN HAS THE ABILITY TO REORGANIZE TO COMPENSATE FOR DEFICIENCIES IN DAMAGED AREAS 2 BECAUSE OF PLASTICITY, LOSS OF COMPLETE FUNCTION DUE TO LESIONS IS LESSENED AND IN MANY CASES DEFICIENCIES WERE NOT EVEN DETECTED 3 THE SIZE OF THE LESION MATTERS IN TERMS OF FUNCTIONALITY AND RECOVERY

  19. LASHEY (1929) • RATS PERFORMING MEMORY AND RETENTION TASKS IN A MAZE WERE FOUND TO REQUIRE ALL AREAS OF THE CEREBRAL CORTEX- THE AMOUNT OF IMPAIRMENT IN THESE TASKS WAS DIRECTLY PROPORTIONAL TO THE AMOUNT OF TISSUE LOST • VISUAL CORTEX STUDIES FOUND THAT COMPLETE REMOVAL OF ASSOCIATED CORTICAL TISSUES RESULTED IN LOSS OF ALL PATTERN DISCRIMINATION • A REMOVAL THAT LEFT A SMALL AMOUNT OF TISSUE REMAINING WAS ENOUGH TO RETAIN SOME CAPACITY

  20. CHAPMAN AND WOLFF (1959) INTERESTED IN TESTING LASHLY’S IDEA THAT THERE WERE REGIONAL DIFFERENCES IN HUMANS RATHER THAN JUST ANIMALS • THEY USED PATIENTS THAT HAS LESIONS EXCIZED SURGICALLY • NEUROSUGEONS ESTIMATED THE AMOUNT OF TISSUE LOST • A BATTERY OF TESTS WERE GIVEN TO TEST COGNITIVE FUNCTION • IT WAS FOUND THAT THE ONLY THING TO AFFECT THE DEGREE OF IMPAIRMENT WES THE SIZE OF THE LESION

  21. 0GDEN AND FRANZ (1917) FOCUSED ON STUDIES ON COMPLETE RECOVERY OF PARALYSIS AFTER LESIONS TO THE CORTICAL MOTER REGION IN MONKEYS • RECOVERY: FORCED TO USE THE HEMIPLEGIC ARM • NO RECOVERY: NOT FORCED TO USE HEMIPLEGIC ARM • THIS SUPPORTED THE IDEA THAT DUE TO PLATICITY OF THE BRAIN, ADJACENT AREA WERE ABLE TO BE “TAUGHT” TO ASSUME RESPONSIBILITIES FOR THE DAMAGED CORTEX

  22. PLASTICITY • THE EARLY CONCEPT OF “PLASTICITY” WAS CONTINOUSLY TESTED AND REFINED BY NEUROSCIENTIST INTO THE 20TH CENTURY • AN AREA OF PARTICULR INTEREST WAS THE PLASTICITY OF CHILDREN COMPARED TO ADULTS

  23. PLASTICITY SOME OF THE PROMINENT RESEARCHERS OF THE EARLY 20TH CENTURY WERE: *HINSHELWOOD(1904)/THOMAS(1905): FOCUS: THEACHING DYSLEXIC CHILDREN TO WRITE WITH LEFT HAND TO STREGTHEN RIGHT ANGULAR GYRUS TO ASSUME THE FUNCTION OF READING *HILLER (1954) FOCUS: 14 Y/O PATIENT WITH LEFT HEMISPHERECTOMY FOR TUMOR REMOVAL POST-SURGICALLY WAS APHASIC-COMPARED TO OLDER PATIENTS WHO UNDERWENT THE SAME PROCEEDURE-HILLER’S PATIENT SHOWED CONSIDERABLE RECOVERY IN UNDERSTANDING AND EXPRESSION OF SPEECH

  24. FOERSTER and GOLDSTEIN FOERSTER: • FOCUSED ON THE CHANGES IN THE NERVOUS SYSTEM THAT OCCUR AFTER INJURY • CONCEPT OF REGENERATION AND REORGANIZATION AS THE FEATURES OF RECOVERY • AS A NEUROSURGEON, MAIN EMPHASIS WAS ON ANALYSIS OF REORGANIZATION AS AN ASPECT OF SURGICAL INTERVENTION GOLDSTEIN: • NOT CONCERNED WITH ANATOMOPHYSIOLOGIC ASPECTS • MORE FOCUSED ON THE DRIVE AND WILL OF THE PATIENT TO REACH OPTIMAL ADAPTATION • INSTEAD OF PLACING EMPHASIS ON DEFECT, PATIENTS WITH BRAIN INJERIES NEED TO “REORGANIZE” AND IN EFFECT, FOCUS ON ADAPTABILITY RATHER THAN ELIMINATING SYMPTOMS

  25. DEVELOPMENT OF FUNCTIONAL IMAGING PROCEDURES 1.) MRI (MAGNETIC RESONANCE IMAGING) : non-evasive technique that records the responses to radio waves, or other forms of energy, of different types of molecules in a magnetic field. *Different tissues of the body emit different amounts of energy in response to pulses. 2.) PET SCAN (POSITRON EMISSION TOMOGRAPHY) : non-evasive technique that monitors regional cerebral blood flow in the brain by recording the emission, or radiation, of gamma rays; produces a color-coded record of brain activity. *Gamma rays: emitted and radiate in opposite directions and can be recorded by a ring of detectors around the person’s head.

  26. DEVELOPMENT OF FUNCTIONAL IMAGING PROCEDURES 3.) SPECT SCAN (SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY): brain imaging system similar to a PET scan, but does not produce as clearly defined images as the PET scan. 4.) CT SCAN (COMPUTED/COMPUTERIZED TOMOGRAPHY SCAN): non-evasive system used for brain imaging or visualizing other organs of the body; computer builds a 3-D picture from a series of cross-sectional X-rays taken over evenly spaced time intervals over time. *(A.k.a. CAT scan, or computed axial tomography scan)* [By 1995, PET scans were being used to study patients with stroke in either the left or right hemispheres of the brain to assess possible damage]

  27. Kertesz (1993) • QUESTIONED HOW THE RIGHT HEMISPHERE STRUCTURES RECOVERED AFTER BRAIN INJURY OR STROKE • THE IDEA THAT THE CAPACITY OF THE RIGHT HEMISPHERE WAS RESPONSIBLE FOR CERTAIN FUNCTIONS SINCE AS FAR BACK AS NIELSEN (1946)

  28. Hubel & Wiesel (1970) • DECADES AFTER WWII, THE FIELD OF NEURAL PLASTICITY DEVELOPED FROM THE EXPERIMENTS OF HUBEL & WIESEL • FOCUS WAS SPECIFICALLY ON THE IDEA OF THE CRITICAL PERIOD, WHICH IS THE DETERMINED STATE OF DEVELOPMENT AT WHICH A PERSON OR ANIMAL IS OPTIMALLY READY TO ACQUIRE SOME PATTERN OF BEHAVIOR (I.E. SIGHT BEGINS ONCE THE EYES ARE FIRST OPEN AND EXPOSED TO STIMULI, SUCH AS LIGHT). • SUGGESTED THE NEURAL AND SENSORY SYSTEMS WERE HIGHLY PLASTIC DURING A BRIEF POINT IN DEVELOPMENT.

  29. Johnson & Almli (1978) DISCUSSED METHODS OF RECOVERY: • SUBSTITUTION- IMPLYING SURPLUS OR MULTIPLE REPRESENTATION IN THE CNS, WHICH WORKS AS A SECONDARY NEURAL SYSTEM TO TAKE OVER THE FUNCTION OF A PRIMARY ONE. • VICARIATION/EQUIPOTENTIALITY- NON-SPECIFIED BRAIN AREAS THAT ASSUME THE FUNCTIONS OF THE DAMAGED ONE. • REGENERATION-NEW GROWTH AFTER NEURON DAMAGE. • COLLATERAL SPROUTING- NEW GROWTH IN AREAS ADJACENT TO DAMAGED TISSUE. • DENERVATION SENSITIVITY- INCREASED SENSITIVITY TO TRANSMITTER SUBSTANCES BY NEURONS THAT HAVE LOST DUE TO INNERVATION DUE TO BRAIN DAMAGE

  30. OTHER DEVELOPMENTS • Early 1980s, evidence of plasticity in adults begins to emerge, along with the development of sensory and motor maps. • Huttenlocher (1990) studied the cerebral cortex and developmental changes in relation to early learning in childhood. • Pascual-Leone (1993) researched the increased cortical responses of the index finger in reading Braille.

  31. INTERMODAL PLASTICITY • In the late 1960s, Paul Bach-y-Rita developed tactile vision substitution system (TVSS) to investigate intermodal plasticity among people who were blind. • The TVSS allowed the blind eye to receive “visual” information by mechanical vibrations or electric pulses. • The TVSS was never a fully accepted, but effected the concept of intermodal plasticity. • Studies using intermodal plasticity in humans that were blind showed activated brain activity in brain regions normally associated with vision during other forms of stimulation (i.e. auditory).

  32. Sensory Mapping • Sensory Mappingmay explain why people with an amputated limb way still feel or perceive sensations and inputs although there is no longer a limb present to receive stimulation, known as the “phantom limb,” or why blind people can learn to read Braille or seem to have heightened hearing.

  33. SUMMARY • The study of neural plasticity and recovery of function after surgery has continued for more than a century, but has really exploded in the last 10 years. • Addresses theoretical and empirical issues related to neural plasticity. • Findings in neural plasticity have lead to major influences on the development of rehabilitation programs.

  34. SUMMARY • *Dramatics advance in technical tools that have enhanced the field: MRI, PET, SPECT, and CT scans, which have in turn helped to advance other neurological discoveries. • *The goal is to develop answers and effective treatments for people who suffer from cognitive and/or behavioral problems due to some neurological disease or dysfunction

  35. THANKS FOR LISTENING

  36. WHAT WILL HAPPEN IF WE DON'T GET A GOOD GRADE! FLEURENS LESIONED PIGEON

  37. JEOPARDY

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