Symptoms and signs caused by neural plasticity
Download
1 / 70

SYMPTOMS AND SIGNS CAUSED BY NEURAL PLASTICITY - PowerPoint PPT Presentation


  • 153 Views
  • Uploaded on

SYMPTOMS AND SIGNS CAUSED BY NEURAL PLASTICITY. Signs and symptoms of disorders. Not everything can be seen on MRI or other imaging techniques Not everything has positive laboratory tests. Neural plasticity play greater role in generating symptoms and signs than previously assumed.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'SYMPTOMS AND SIGNS CAUSED BY NEURAL PLASTICITY' - fordon


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Signs and symptoms of disorders
Signs and symptoms of disorders

  • Not everything can be seen on MRI or other imaging techniques

  • Not everything has positive laboratory tests


Neural plasticity play greater role in generating symptoms and signs than previously assumed
Neural plasticity play greater role in generating symptoms and signs than previously assumed

  • Plastic changes are reversible

  • Treatments without medicine and surgery may alleviate pain and tinnitus


Neural plasticity
Neural plasticity and signs than previously assumed

  • The brain is far from being a fixed system but it is continuously shaped and re-shaped by what it receives from the outside world.

  • Sensory systems provide the input that shapes the brain.


Neural plasticity1
NEURAL PLASTICITY and signs than previously assumed

  • Adjust the nervous system to changing demands (based on sensory input)

  • Compensate for deficits through injury or diseases

  • Cause symptoms and signs of diseases


Promoters of neural plasticity
PROMOTERS OF NEURAL PLASTICITY and signs than previously assumed

  • Deprivation of sensory input

  • Overstimulation


Deprivation
DEPRIVATION and signs than previously assumed

  • “Use it or loose it”


Neural plasticity2
NEURAL PLASTICITY and signs than previously assumed

  • NEURAL PLASTICITY IS AN ABILITY OF THE NERVE CELLS TO CHANGE THEIR FUNCTION OR STRUCTURE

  • THE CHANGES OCCUR WITHOUT DETECTABLE MORPHOLOGIC CHANGES (USING STANDARD CLINICAL METHODS)


Functional changes are caused by
FUNCTIONAL CHANGES ARE CAUSED BY: and signs than previously assumed

  • CHANGE IN SYNAPTIC EFFICACY

  • CHANGE IN NEURAL EXCITABILITY

  • ELIMINATION OF NERVE CELLS (APOPTOSIS)

  • CREATION OR ELIMINATION OF CONNECTIONS (AXONS AND DENDRITES)


Symptoms and signs
SYMPTOMS AND SIGNS and signs than previously assumed

  • HYPERACTIVITY

  • HYPERSENSITIVITY

  • CHANGE IN NEURAL PROCESSING

  • CHANGE IN PERCEPTION OF SENSORY INPUT

  • CHANGE IN MOTOR FUNCTION


Hyperactivity
HYPERACTIVITY and signs than previously assumed

  • MUSCLE SPASM

  • TINNITUS

  • PARESTHESIA (TINGLING)

  • PAIN


Success of treatment supports hypotheses of neural plasticity
Success of treatment supports hypotheses of neural plasticity

  • Pain can be alleviated by electrical stimulation

  • Tinnitus can be alleviated by sound stimulation


Hyperactivity of the vestibular system
Hyperactivity of the vestibular system plasticity

  • Ménière's disease

    • Air puffs applied to the inner ear can reverse symptoms


Hypersensitivity
HYPERSENSITIVITY plasticity

  • LOWERED THRESHOLD FOR SENSORY STIMULATION

  • EXAGGERATED REACTION ON SENSORY STIMULI


Change in neural processing
CHANGE IN NEURAL PROCESSING plasticity

  • ALLODYNIA

    (PAIN FROM INNOCUOUS STIMULATION)

  • HYPERPATHIA

    (LOWERED TOLERANCE TO MODERATE PAIN AND PROLONGED PAIN SENSATION)

    CROSS MODAL INTERACTION


Mechanisms of neural plasticity
MECHANISMS OF NEURAL PLASTICITY plasticity

  • CHANGE IN SYNAPTIC EFFICACY

  • NEW CONNECTIONS (SPROUTING)


Unmasking of dormant synapses may cause
UNMASKING OF DORMANT SYNAPSES MAY CAUSE: plasticity

  • INCREASE OF SENSORY RESPONSE AREAS

  • SPREAD OF MOTOR ACTIVATION (SYNKINESIS)

  • ACTIVATION OF NEW BRAIN REGIONS MAY (“RE-WIRING”)


Extension of activation of motor areas may cause synkinesis
EXTENSION OF ACTIVATION OF plasticityMOTOR AREAS MAY CAUSE SYNKINESIS

  • FACIAL SYNKINESIS AFTER INJURY TO THE FACIAL NERVE

  • LATERAL SPREAD OF BLINK REFLEX IN HEMIFACIAL SPASM


Activity dependent synaptic plasticity
ACTIVITY DEPENDENT SYNAPTIC PLASTICITY plasticity

  • LONG TERM POTENTIATION (LTP)

  • LONG TERM DEPRESSION (LTD)

    • HIGH-FREQUENCY TRAINS ARE EFFECTIVE IN INDUCING LTP

      (IS THE “NOVEL STIMULATION” OFTEN REFEREED TO IN NEURAL PLASTICITY A HIGH FREQUENCY TRAIN?)


Activity dependent synaptic plasticity1
ACTIVITY DEPENDENT SYNAPTIC PLASTICITY plasticity

  • ACETYLCHOLINE IS IMPORTANT IN DEVELOPMENT

  • NICOTINIC ACETYLCHOLINE RECEPTORS MAY MODULATE GLUTAMATE RECEPTORS

    • MEDIATE LONG TERM CHANGES IN SYNAPTIC EFFICACY

    • AFFECT MATURATION OF THE NERVOUS SYSTEM


Activity dependent synaptic plasticity2
ACTIVITY DEPENDENT SYNAPTIC PLASTICITY plasticity

  • SYNCHRONOUS PRE AND POST-SYNAPTIC ACTIVATION PROMOTE NEURAL PLASTICITY

    • HEBB’S PRINCIPLE: “NEURONS THAT FIRE TOGETHER WIRE TOGETHER”


Activity dependent synaptic plasticity3
ACTIVITY DEPENDENT SYNAPTIC PLASTICITY plasticity

  • THE TEMPORAL PATTERN OF NEURAL ACTIVITY IS IMPORTANT


New brain regions may become activated
NEW BRAIN REGIONS MAY BECOME ACTIVATED plasticity

  • DISORDERS OF THE VESTIBULAR SYSTEM

    • AWARENESS OF HEAD MOVEMENTS

    • DIZZINESS

    • NAUSEA AND VOMITING


New brain regions may become activated1
NEW BRAIN REGIONS MAY BECOME ACTIVATED plasticity

  • CHRONIC PAIN

    • ALLODYNIA

    • INVOLVEMENT OF THE SYMPATHETIC NERVOUS SYSTEM; RSD*)

      *) REFLEX SYMPATHETIC DYSTROPHY


New brain regions may become activated2
NEW BRAIN REGIONS MAY BECOME ACTIVATED plasticity

  • ACTIVATION OF NON-SPECIFIC PATHWAYS THROUGH SUBCORTICAL ROUTES

  • INVOLVEMENT OF THE LIMBIC SYSTEM




Symptoms and signs of neuropathic pain
Symptoms and signs of neuropathic pain disorders

  • Strong emotional components

  • Depression

  • High risk of suicide


The amygdala is involved in fear and other mood disorders1
The amygdala is involved in fear and other mood disorders disorders

  • Subcortical connections to the amygdala may induce emotional response unconsiously

    • uncontrollable fear and rage


Involvement of limbic system structures
INVOLVEMENT OF LIMBIC SYSTEM STRUCTURES disorders

  • AFFECTIVE DISORDERS

    • DEPRESSION IN PAIN AND TINNITUS


Involvement of limbic system structures1
INVOLVEMENT OF LIMBIC SYSTEM STRUCTURES disorders

  • EMOTIONAL REACTIONS TO STIMULI THAT NORMALLY DO NOT CAUSE SUCH REACTIONS

  • EXAMPLES:

    • CHRONIC PAIN (HYPERPATHIA)

    • SEVERE TINNITUS (PHONOPHOBIA)


Connections from the auditory system to the amygdala
Connections from the auditory system to the amygdala disorders

  • Cortical-cortical connections (the “high route”)

  • Subcortical connections

    (the “low route”)


How can pain information reach the amygdala
How can pain information reach the amygdala? disorders

  • Through the thalamus

  • Through routes that are enhanced by expression of neural plasticity (re-routing of information)


Main connections to the amygdala
MAIN CONNECTIONS TO THE AMYGDALA: disorders

  • THALAMUS (MEDIODORSAL)

  • PREFRONTAL CORTEX

    • (VIA MEDIODORSAL THALAMUS)

  • SEPTAL NUCLEI

  • PERIAQUEDUCTAL GRAY (PAG)

  • TEMPORAL ASSOCIATION CORTEX

  • MOST CONNECTIONS ARE RECIPROCAL


The “high route” and disordersthe “low route” to the amygdala

Auditory cortex

Thalamus

Connections from the amygdala

From: Møller: Sensory Systems, 2002


Connections from a sensory system to the amygdala disorders

“the high route”

From: Møller: Sensory Systems, 2003


High route

SLOW disorders

CARRIES HIGHLY PROCESSED INFORMATION

“SLOW AND ACCURATE”

HIGH ROUTE


Connections from a sensory system to the amygdala disorders

“the low route”

From: Møller: Sensory Systems, 2003


Low route
LOW ROUTE disorders

  • IS FAST

  • CARRIES UNPROCESSED INFORMATION

    • “FAST AND AND DIRTY”


Connections from the amygdala disorders

From: Møller: Sensory Systems, 2003


Conclusion
CONCLUSION disorders

  • ACTIVATION OF NON-CLASSICAL ASCENDING SENSORY PATHWAYS CAN CAUSE SYMPTOMS AND SIGN OF SEVERAL DISEASES


MANY REGIONS OF THE BRAIN ARE CONNECTED disorders

Which routes are active?

Depends on synaptic efficacy


Sensory input causes abnormal emotional reactions
SENSORY INPUT CAUSES ABNORMAL EMOTIONAL REACTIONS disorders

  • TINNITUS

  • PHONOPHOBIA AND HYPERACUSIS

  • DIZZINESS

  • ALLODYNIA

  • CHRONIC PAIN

  • AUTISM


Involvement of the limbic system in hearing
INVOLVEMENT OF THE LIMBIC SYSTEM IN HEARING: disorders

  • UNMASKING OF CONNECTIONS FROM THE CLASSICAL AUDITORY SYSTEM TO COMPONENTS OF THE LIMBIC SYSTEM INVOLVING:

    • MEDIO-DORSAL MEDIAL GENICULATE BODY

    • ASSOCIATION CORTICES

    • AMYGDALOID NUCLEI


Classical auditory disorders

pathways

Non-classical

auditory pathways

From: Møller: Sensory Systems, 2003


Escapable and inescapable fear

ESCAPABLE disorders AND INESCAPABLE FEAR


Autism
AUTISM disorders

  • ABNORMAL PERCEPTION OF SENSORY INPUT

  • MAY BE CAUSED BY ABNORMAL INVOLVEMENT OF THE AMYGDALA


Autism1
AUTISM disorders

  • Kluver-Bucy wrote in 1939 regarding the effect of bilateral amygdalectomy in monkeys:

  • “Monkeys are no longer capable of functioning as members of social groups. They cannot recognize the social significance of the exteriorceptive (especially visual, auditory and olfactory) signals that regulate social behavior, or relate then to their own affective states (moods), which regulate approach to or avoidance of other members of the group and are thus the building blocks of social interactions. They avoid other members of the group and seem anxious and insecure”.


Autism2
AUTISM disorders

  • Similarities with the Klüver-Bucy syndrome


Autism3
AUTISM disorders

  • SPECULATION:

  • Insufficient pruning or apoptosis is involved in autism

    • THE AMYGDALA IN AUTISTIC CHILDREN SEEMS TO HAVE A HIGHER DENSITY OF CELLS THAN NORMAL.


Autism4
AUTISM disorders

  • SPECULATION:

    • NONSPECIFIC SENSORY PATHWAYS MAY BE HYPERACTIVE CAUSING TOO MUCH INPUT TO ASSOCIATION CORTICES AND LIMBIC STRUCTURES.

    • SPECIFIC SENSORY PATHWAYS MAY BE HYPOACTIVE SO THAT LESS INPUT REACHES PRIMARY CORTICES.


How can we test if nonspecific pathways are involved
HOW CAN WE TEST IF NONSPECIFIC PATHWAYS ARE INVOLVED: disorders

  • NONSPECIFIC SENSORY PATHWAYS ARE POLYMODAL

  • EXAMPLE: STIMULATION OF THE SOMATOSENSORY SYSTEM CHANGE PERCEPTION OF TINNITUS


How can nonspecific pathways become activated
HOW CAN NONSPECIFIC PATHWAYS disordersBECOME ACTIVATED?

  • UNMASKING OF DORMANT SYNAPSES

  • CREATION OR ELIMINATION OF NERVE CELLS


How can nonspecific pathways become activated1
HOW CAN NONSPECIFIC PATHWAYS disordersBECOME ACTIVATED?

  • CREATION OR ELIMINATION OF NERVE CELLS

    • REQUIRES TIME TO DEVELOP

    • AGE RELATED


Unmasking of dormant synapses
UNMASKING OF DORMANT SYNAPSES disorders

  • ACTS INSTANTLY

  • DEPENDS ON INPUT

  • DEPENDS ON TEMPORAL INTEGRATION

  • DEPENDS ON AVAILABILITY OF NEURAL TRANSMITTERS

  • CAN BE MANIPULATED BY DRUGS


How do synapses become dormant
HOW DO SYNAPSES BECOME DORMANT? disorders

  • DURING (NORMAL) CHILDHOOD DEVELOPMENT

  • THROUGH STIMULATION (SENSORY INPUT)


Synaptic receptors undergo changes during maturation
SYNAPTIC RECEPTORS UNDERGO CHANGES disordersDURING MATURATION

  • GABA CAN BE EXCITATORY IN IMMATURE TISSUE.

  • GABA SYNTHESIS DECREASES WITH AGE

  • ONLY NMDA RECEPTORS IN IMMATURE TISSUE


Conclusion1
CONCLUSION disorders

  • ACTIVATION OF NON-CLASSICAL ASCENDING SENSORY PATHWAYS CAN CAUSE SYMPTOMS AND SIGN OF SEVERAL DISEASES


Ontogenetic development depends on
ONTOGENETIC DEVELOPMENT DEPENDS ON: disorders

  • GENETICS (AND EPIGENETICS)

  • STIMULATION (SENSORY INPUT) “NEURONS THAT FIRE TOGETHER WIRE TOGETHER” (HEBB, 1949).

  • OTHER ENVIRONMENTAL FACTORS

  • CHEMICAL FACTORS (DRUGS, ALCOHOL ETC.)

  • UNKNOWN FACTORS


Ontogenetic childhood development shapes the nervous system by
ONTOGENETIC (CHILDHOOD) DEVELOPMENT SHAPES THE NERVOUS SYSTEM BY:

  • APOPTOSIS

  • PRUNING OF AXONS AND DENDRITES

  • CHANGE IN SYNAPTIC EFFICACY


Normal development of the central nervous system involves
NORMAL DEVELOPMENT OF THE CENTRAL SYSTEM BY:NERVOUS SYSTEM INVOLVES:

  • APOPTOSIS

  • ADJUSTMENT OF SYNAPTIC EFFICACY


Abnormal development of the central nervous system may be caused by
ABNORMAL DEVELOPMENT OF THE CENTRAL SYSTEM BY:NERVOUS SYSTEM MAY BE CAUSED BY:

  • FAILURE TO BLOCK SYNAPSES

  • INADEQUATE PRUNING OF THE NERVOUS SYSTEM

    MAY PLAY A ROLE IN:

  • DEVELOPMENTAL DISORDERS

  • OCULAR DOMINANCE

  • AUTISM


What cause plastic changes of the cns
WHAT CAUSE PLASTIC CHANGES SYSTEM BY:OF THE CNS?

  • DEPRIVATION OF INPUT

  • NOVEL INPUT

  • ACTIVITY GENERATED BY INJURY

  • UNKNOWN FACTORS


Plastic changes of the nervous system are reversible
PLASTIC CHANGES OF THE NERVOUS SYSTEM ARE REVERSIBLE SYSTEM BY:

  • THE ASSOCIATED DISORDERS ARE TREATABLE

    • DEPENDING ON CORRECT DIAGNOSIS


Disorders caused by neural plasticity are treatable
DISORDERS CAUSED BY NEURAL PLASTICITY ARE TREATABLE SYSTEM BY:

  • EXAMPLES:

    • ELECTRICAL STIMULATION (TENS) CAN ALLEVIATE NATUROPATHIC PAIN

    • TRAINING CAN REDUCE SYNKINESIS

    • TRAINING CAN REDUCE TINNITUS


Examples of reversal of neural plasticity
EXAMPLES OF REVERSAL OF NEURAL PLASTICITY SYSTEM BY:

  • “TENS” (TRANSDERM ELECTRIC NERVE STIMULATION) HAS BEEN USED FOR MANY YEARS IN TREATMENT OF CHRONIC PAIN

  • RECENTLY SOUND STIMULATION IN VARIOUS FORMS HAVE BEEN INTRODUCED IN TREATMENT OF SEVERE TINNITUS


Stimulation of somatosensory system can relieve tinnitus
Stimulation of somatosensory system can relieve tinnitus SYSTEM BY:

  • Electrical stimulation of the ear or the skin behind the ears have been used to treat tinnitus

  • Few systematic studies of efficacy have been published


Conclusion disorders caused by functional changes of the central nervous system
CONCLUSION SYSTEM BY:DISORDERS CAUSED BYFUNCTIONAL CHANGES OF THE CENTRAL NERVOUS SYSTEM:

  • FEW AND OFTEN AMBIGUOUS SYMPTOMS AND SIGNS

  • OFTEN DIAGNOSED INCORRECTLY

  • OFTEN TREATED INEFFECTIVELY IF AT ALL