Cognitive Neuropsychology Presentation on TMS

Unsettling the Brain
{ The Functions & Applications of
Transcranial Magnetic Stimulation (TMS)
2. 15. 2012 | A Cognitive Neuropsychology Presentation

Domingo
See
Yu
Quijano
Tan

Thursday, February 16, 12

First, a
demonstration!


Transcranial
Magnetic
Stimulation


The Procedure
1. Coil is placed near the head of the
patient
2. Electrical current flows in
opposite directions and come
together at the center-point
3. Magnetic field penetrates the
brain & induces an electric field in
the underlying region of the
cerebral cortex
4. Stimulates excitation &
organization of neuronal firing in
stimulated region.


What is Transcranial Magnetic Stimulation?
• First introduced by Anthony Barker & his colleagues in 1985

• Based on the principle of electromagnetic induction

• The production of an electric current across a conductor moving
through a magnetic ﬁeld
• a method that disrupts normal brain processes
• helps “simulate” brain damage in normal people


What is Transcranial Magnetic Stimulation?
• the primary materials used:
magnets and coils

• magnetic ﬁelds can induce
electrical activity in speciﬁc
regions of the brain and
affect its respective functions

• TMS directly affects brain
functioning, unlike fMRI,
which merely observes brain
activity


How does it work?
Michael Faraday
an English chemist and physicist who discovered
electromagnetic induction

His illustration
1. When an electrical current is passed through a wire, it
generates a time-varying magnetic field.

2. If a second wire is placed nearby, the magnetic field
induces electrical current flow in that second wire.

In TMS:
the ‘first wire’ is the stimulating coil
the ‘second wire’ is a targeted region of the brain.


Transcranial Magnetic Stimulation
can stimulate peripheral nerves & brain tissues in in studies
encompassing
Motor conduction in human development
Motor control
Movement disorders
Vision
Attention
Memory
Speech & language
Epilepsy
Depression
Stroke
Pain & plasticity
Swallowing

How does it work?

Instrument: Figure-of-
Eight Shaped Coil


Secondary Effects
Although the stimulation is maximal on the cortical region (cortex),
the stimulation also has an (secondary) effect on connected areas
of the cortex.
E.g. When the left motor cortex is stimulated, there are 3 likely
effects of stimulation:
a. change in activity in the targeted region
b. change in activity in immediately surrounding areas of
cortex
c. change in activity of cortical areas directly connected with
the stimulated region
It is important to consider to keep an open-mind with the effects of
the stimulations.

Stimulating the left hemisphere with TMS


Stimulating the left hemisphere with TMS

2. Tiny magnetic pulses
disturb circuits on left side of
brain that usually sees the
bigger picture, and
suppresses the detail-
hoarding right side.

3. Details unconsciously
1. A cap with the magnetic come to the core, creating a
coil connected to a current burst of mathematical or
is placed on the head. other talent


TMS to left hemisphere to disrupt language (uploaded Jan 23, 2012)

A TMS Study on
Savant Autism


The Study of Autistic Savants

Savant-like skills exposed in normal people by
suppressing the left-fronto-temporal lobe

(Synder et al., 2003)

Savant [sa-vahnt]
(n.) a learned person
a person of profound or extensive learning


To help explain what a savant is:

Dustin Hoffman in Rain Man
- portrayed an autistic named
Raymond Babbitt
- has astounding memory for
- baseball statistics
- the phone book
- has great ability to “count
cards” (a strategy in blackjack)


Research Goals

• To test whether savant-like skills can be found in healthy people

• “If neurological impairment is the cause of the autistic's
disabilities, could it be the cause of their genius-like abilities,
too?

• Through the use of the TMS device, neuroscientists can identify the
role of the left fronto-temporal lobe in the savant syndrome and
explain how inihibiting it can create almost savant-like skills.


Method
• Repetitive Transcranial Magnetic Stimulation (rTMS) was delivered for
15 min. over the left fronto-temporal lobe of 11 healthy participants
• Participants were required to complete drawing & proofreading tasks

• Participant performance on each of the tasks was evaluated:

• Before the real and placebo magnetic stimulation
• During the real and placebo magnetic stimulation

• Immediately after real and placebo magnetic stimulation

• 45 min. after 15 min of real and placebo magnetic stimulation


Results: Drawing Task

• After 10 minutes of stimulation, N.R. and A.J. radically changed
their schema for dogs from their initial 2 drawings before
stimulation. During and after stimulation, the style dramatically
changed, with the drawings becoming more complex.

• The horses of D.C. became more life-like, even ﬂamboyant,
compared to the drawing he completed before stimulation.


Results: Drawing Task 1



Participant D.C.

After 10 min of After 15 min of 45 min after
Before TMS TMS TMS TMS ceased



• During and after real stimulation, R.Y. changed his convention for
drawing faces.
• In the placebo stimulation a distinct schema is present in the
drawings of R.Y.
• During and after real stimulation, this style changed and R.Y.
became preoccupied by the details of eyes.
• These drawings were executed in one minute by R.Y. after
viewing the corresponding image of ﬁgure 4 for 30 seconds.



Participant R.Y.



After 10 min After 15 min 45 min after
Before TMS of TMS of TMS TMS ceased


Implications of Results: Drawing Task

• Magnetic stimulation caused a major change in the schema
or convention of the drawings


Proofreading Task

Sample

a
bird
in
the
the
hand
is
worth

two
in
the
bush

Without
s)mula)on,
par)cipants
almost
always

missed
the
duplicated
‘the’
in
the
sentence.


Proofreading Task

• Proverbs
• A series of 10 proverbs was presented on a screen.
• Each proverb was presented on the screen for 2s, during which
time the participant read the proverb aloud.
• 2 proverbs in the set contained an error where a word was
duplicated
• Paragraph
• A paragraph appeared on the screen, which the participant read
aloud. It also contained 2 duplicate word errors and a few errors
in spelling and grammar.
• Participants were instructed to read the whole text including the
errors

Results: Proofreading Task
• D.C. and R.Y. displayed a noticeable improvement in ability
to recognize duplicate words.
• They did comparatively well during and/or immediately after
stimulation and comparatively poorly both before and 45 min
after.
• These were the same participants who displayed pronounced
style changes in their drawings.
• No improved proofreading or drawing abilities were
associated with placebo stimulation.
• This suggests any improvements seen with placebo
stimulation were merely a consequence of learning.


Results

Enhanced Altered
Change in drawing
proofreading psychological
style
ability experience

D.C D.C D.C

R.Y. R.Y. R.Y.

A.J. *

N.R. N.R.

* did not give a subjective report


Implications of Results: Proofreading Task

• Unlike autistic savants, our propensity to impose meaning
and concept blocks our awareness for details making up
the concept

• There is non-subjective evidence of the ability to switch on
a savant-like skill by turning off part of the brain in healthy
individuals.

• Without stimulation, participants almost always missed
errors such as the repeated 'the' even after many exposures.
This fact is illustrated by the poor performance of all
participants who received placebo stimulation.


Study 2

Savant-like Numerosity Skills Revealed In
Normal People By Magnetic Pulse
(Snyder et al., 2006)


Goals ❖ Method ❖ Results
• Research goal
• To test whether normal individuals are capable of savant numerosity
(the ability to instantly answer the exact number of objects)
• Method
• Researchers temporarily stimulated the savant condition in 12
healthy participants by inhibiting the left anterior temporal lobe of
with rTMS and making them guess the exact number of discreet
elements presented to them
• Results
• 10 participants improved their ability to accurately guess the
number of discrete items immediately following rTMS.
• 8 became worse at guessing as the effects of the pulses receded


Advantages
• Opens possibility of changing one’s intelligence

• TMS studies on autism helps researchers to identify brain
mechanisms that account for the disorder

• Once they identify these abnormal mechanisms in
individuals with autism, they can develop treatments to
reverse the symptoms of autism in adults and even treat the
disorder preemptively in a child just as she/he is showing
signs of autism

• Can test the effectivity of drugs in changing the
hyperplasticity of the brain of individuals with autism


Limitations

•Savantism comes from “practice and
specialization” (Howe)
•Practice may explain the improvement in certain
skills i.e. drawing (Hendren)
•Savant-like skills are activated by the inhibition of
the left fronto-temporal lobe only for the duration
of the rTMS.


Other
Applications


1. Depression
• TMS has the capability to be a novel antidepressant
treatment.

• Because TMS is a non-invasive, non-drug therapy, it has
been proven to be an effective, long-term treatment for
major depression.


2. Alzheimer’s Disease Therapy
TMS can improve naming ability in Alzheimer disease patients at
different stages of cognitive decline

3. Risk-Taking Behavior
TMS was used to transiently disrupt left or right dorsolateral
prefrontal cortex (DLPFC) function

It was found that the DLPFC plays a crucial role in the suppressing
risk-taking behavior, conﬁrming the role of the prefrontal cortex in
decision-making.

A fundamental human capacity such as decision-making can be
manipulated in normal subjects through TMS.

Critiques & Limitations of TMS


Minor Short-Term Side Effects
• These side effects are generally mild and typically
improve after the first week or two of treatment.
• Headache
• Scalp discomfort at the site of stimulation
• Tingling, spasms or twitching of facial muscles
• Lightheadedness
• Discomfort from noise during treatment


Uncommon, serious side effects (rare)
• Seizures
• Mania, particularly in people with bipolar disorder
• Hearing loss due to inadequate ear protection during
treatment


Lastly
• TMS effects usually are not limited to the site of
stimulation but spread either physically to
neighboring areas


Advantages
of TMS


A Cause-and-effect approach

• TMS can help in investigating a wide range of brain and
cognitive functions, including the cause-and-effect
relationships of brain activity and behavior, not just their
correlations.

• TMS can enhance the results of other neuroimaging
techniques by establishing the causal link between brain
activity and task performance.

• TMS can help create “virtual lesions”

• Lesion studies are more functional imaging studies


Advantages of virtual lesion studies
TMS studies can be conducted in normal subjects,
thus eliminating the need for studying actual brain
lesions
TMS studies can be conducted intensely and
avoiding any harm to the brain.

TMS studies can be repeated in the same subject,
allowing one to conduct careful, controlled
procedures.

Subjects can be tested with the exact same
procedure, allowing accurate statistical evaluation
of results.


Advantages of virtual lesion studies
Different areas of the brain can be targeted,
which allows one to precisely map brain activity
and behavior disruption in the brain.

Different related behavioral tasks can be
tested, allowing one to identify speciﬁc areas
of the brain to a certain cognitive function,
ruling out more global mental impairment.


A Wide, Diverse Scope of Research
Over 3500 papers have been published using or further
developing the technique in the 20 years following the ﬁrst
demonstration of TMS.


The Future of TMS
Further studies

may shed light into neuropsychology of language and memory

may help enhance behavior and intelligence


In conclusion,

TMS provides a novel approach
to studying the relationship
between brain function and

behavior by creating virtual
patients.


Thank you!


References
• http://www.aetna.com/cpb/medical/data/400_499/0469.html

• http://www.youtube.com/watch?v=DBBDiGvupFw

• http://www.centreforthemind.com/images/savantskills.pdf

• http://www.nytimes.com/2003/06/22/magazine/22SAVANT.html?
pagewanted=all

• http://www.centreforthemind.com/publications/SavantNumerosity.pdf


Cognitive Neuropsychology Presentation on TMS

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