Review: Neuroscience MethodsA little on TMS…
Discussion:Neuroscience of Lies
Timekeeper?
Logistics:Paper Guidelines
The Plan for today :
:15
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THE GOAL
Hey ___, you took brainclasses at MIT. How do they get these brain areaslighting up? What do you make of it?
Question:
How do we study the brain?
What methods can we use to
figure out what the role of a
certain brain area is?
Answers:
lesions
stimulation single cell recording
fmrieeg
lesions
stimulation
single cell recording
fmri
eeg
Direct Indirect
fmri eeg lesion single-cell stimulationCausality:
lesions
stimulation
single cell recording
fmri
eeg
Good Spatial Good Temporal
stimulation
fmri eeg lesion single-cell stimulationPrecision
lesionsstimulation
single cell recording
fmri
eeg
Invasive Non Invasive
stimulation
fmri eeg lesion single-cell stimulation
Transcranial Magnetic Stimulation…
If you want to hear about brain zapping,
you’ve come to the right place
and if you don’t… too bad
What is it and how does it work?
Electromagnetism
Coil Types
Spatial and Temporal Resolution
Neuron Stimulation… proof by motor cortex
What is it and how does it work?
Will it hurt me?
Myths of TMS:
It will give me a seizure
It will damage my brain at high intensities
The effects are permanent
Animal studies show no cell death even with high stimulation rates.
What’s it good for?
Applications of TMS
Clinical Experimental
- Integrity of motor pathways- Treatment of depression Single Pulse Repetitive
- Motor System probe
- Virtual Scotoma
- Blind Braille readers
- Working memory disruptions
- Sequence learning
Mythical Applications of TMS
Induce creativity (Australian report)
“I looked down at my work. The first felines were boxy and stiffly unconvincing. But after I had been subjected to about 10 minutes of transcranial magnetic stimulation, their tails had grown more vibrant, more nervous; their faces were personable and convincing. They were evenbeginning to wear clever expressions. I could hardly recognize them as my own drawings, though I had watched myself render each one, in all its loving detail. Somehow over the courseof a very few minutes, and with no additional instruction, I had gone from an incompetent draftsman to a very impressive artist of the feline form.
As remarkable as the cat-drawing lesson was, it was just a hint of (Allan) Snyder's work and its implications for the study of cognition. He has used TMS dozens of times on university students, measuring its effect on their ability to draw, to proofread and to perform difficult mathematicalfunctions like identifying prime numbers by sight. Hooked up to the machine, 40 percent of test subjects exhibited extraordinary, and newfound, mental skills. That Snyder was able to induce these remarkable feats in a controlled, repeatable experiment is more than just a greatparty trick; it's a breakthrough that may lead to a revolution in the way we understand the limits of our own intelligence -- and the functioning of the human brain in general.”
From the New York Times: Savant for a Day, June 22, 2003, By LAWRENCE OSBORNE
What’s it good for?
Applications of TMS
Clinical Experimental
- Integrity of motor pathways- Treatment of depression Single Pulse Repetitive
- Motor System probe
- Virtual Scotoma
- Reading Braille
Hope that it might be substitute for electroconvulsive therapy?
- Working memory disruptions
- Sequence learning
What’s it good for?
Applications of TMS
Clinical Experimental
- Integrity of motor pathways- Treatment of depression Single Pulse Repetitive
- Motor System probe
- Virtual Scotoma
- Reading Braille
- Working memory disruptions
- Sequence learning
What’s it good for?
Applications of TMS
Clinical Experimental
- Integrity of motor pathways- Treatment of depression Single Pulse Repetitive
- Motor System probe
- Virtual Scotoma
- Reading Braille
- Working memory disruptions
- Sequence learning
What’s it good for?
Applications of TMS
Clinical Experimental
- Integrity of motor pathways- Treatment of depression Single Pulse Repetitive
- Motor System probe
- Virtual Scotoma
- Reading Braille
- Working memory disruptions
- Sequence learning
PET activation in blind individuals when reading Braille.
PET activation in sighted individuals when doing tactile discrimination task.
Blind individuals doing identification task with Braille
Sighted individuals doing identification task with embossed Roman letters
Assessing functional relevance: TMS during tactile exploration
What’s it good for?
Applications of TMS
Clinical Experimental
- Integrity of motor pathways- Treatment of depression Single Pulse Repetitive
- Motor System probe
- Virtual Scotoma
- Reading Braille
- Working memory disruptions
- Sequence learning
for the economically minded: How much does this cost?
Neopulse 40K
Magstim 30 K
Polaris & Brainsight 60 K
EMG setup 10 K
Brodmann, K., Vergleichende Lokalisationslehre der Grosshirnrinde in ihren Prinzipien dargestellt auf Grund des Zellenbaues. Leipzig: J.A. Barth, 1909.
Broca’s Area:
• language processing
• speech production and comprehension
Broca’s aphasia:
• results from damage to Broca’s Area (e.g., lesions)
• unable to create grammatically-complex sentences
• speech described as telegraphic, contains content words only
• comprehension is relatively normal
Pre-Question Post-Question
Simple (yes/no): Are you a man?
Complex: How old are you?
Two effects:
Main effect (lie>truth, pre and post)
Interaction
Brain-based poloygraph?
Motor Systems Probe:
Mythical Applications of TMSInduce religious experience (Canadian
report)
Cook, CM and Persinger, MA Percept Mot Skills. 1997 85):683-93. Experimental induction of the "sensed presence" in normal subjects and an exceptional subject.
9 of the 15 volunteers who were exposed to successive 3-min. durations of bursts of different types of weak (1 microT) complex magnetic fields or sham-fields reported the sense of a presence as indicated by a button press at the time of the experience… An exceptional subject who had a history of experiencing within his upper left peripheral visual field "flashing images" concerning the health and history of people [when handling their photographs] was also exposed to the burst sequences. Numbers of button presses associated with the experiences of a mystical presence, to whom the subject attributed his capacity, increased when the complex magnetic fields were applied without the subject's knowledge. The results support the hypothesis that the sense of a presence, which may be the common phenomenological base from which experiences of gods, spirits, angels, and other entities are derived, is a right hemispheric homologue of the left hemispheric sense of self.
What’s it good for?
Applications of TMS
Clinical Experimental
- Integrity of motor pathways- Treatment of depression Single Pulse Repetitive
- Motor System probe
- Virtual Scotoma
- Blind Braille readers
- Working memory disruptions
- Sequence learning
Assessment of Motor Pathways in Multiple Sclerosis
TMS stimulation over ulnar nerve
TMS stimulation at C-7 level of spinal cord
TMS stimulation over motor cortex
TMS stimulation over ulnar nerve
TMS stimulation at C-7 level of spinal cord
TMS stimulation over motor cortex
Motor Systems Probe:
Does action observation engage motor system? (Aziz-Zadeh et al., 2002)
Participant watches a movie of person moving either the left or right index finger.
Motor Systems Probe:
High frequency (3 Hz) stimulation
Disruption of sequence production
SMA Stimulation
Motor Cortex Stimulation
SMA: “I forgot where I was in the sequence”
MC: “My hand got stuck.”
Range over which errors occurred after TMS
CONFORMITY & OBEDIENCE:MILGRAM STUDY
Newspaper ad - study of memory - YaleTwo peopleResearcher - here to help science improve learning and memory through punishmnetOne “teacher” and one “learner” - a set of word pairs to memorizeTeacher gives word, learner respondsCorrect response - “good” or “that’s right”Incorrect response - - press button that delivers shock
CONFORMITY & OBEDIENCE:MILGRAM STUDY
Shock Generator15 volts - 15 volts steps - 30 switches150 volts - “STRONG SHOCK”255 volts - “INTENSE SHOCK”375 volts - “DANGER, SEVERE SHOCK”435 volts - “XXX”450 volts - “XXX”
CONFORMITY & OBEDIENCE:MILGRAM STUDY
Initially,learner does wellThen errorsLearner complains that shocks are starting to hurtScreamsSays that he or she does not want to continueHesitate, question researcherLearner complains about heart conditionMore errors - teacher pleads to concentrate“You have no right to keep me here!”“I refuse to answer any more! You can’t hold me here! My hearts bothering me!”At 300 volts, no more responseExperimenter says that after 5 sec, it is a wrong answer
CONFORMITY & OBEDIENCE:MILGRAM STUDY
Shock Generator15 volts - 15 volts steps - 30 switches150 volts - “STRONG SHOCK”255 volts - “INTENSE SCOCK”375 volts - “DANGER, SEVERE SHOCK”435 volts - “XXX”450 volts - “XXX”
All the way to 450?
CONFORMITY & OBEDIENCE:MILGRAM STUDY
Shock Generator15 volts - 15 volts steps - 30 switches150 volts - “STRONG SHOCK”255 volts - “INTENSE SCOCK”375 volts - “DANGER, SEVERE SHOCK”435 volts - “XXX”450 volts - “XXX”
All the way to 450? - 65%
Patient and group of 12 healthy volunteers imagined playing tennis or moving around a house
Owen et al., Science, 2006
Imagery-Specific Activations
If a card has a vowel on one side, then it has an even number on the other side.
E J 6 7
Correct answer - E & 7 (10%)Common answers - E, E & 6
We look for evidence that confirms what we believe, and overlook evidence that could disconfirm what we believe.
E - see an even number - confirm6 - not even needed, but feels like it confirms7 - would disconfirm - if there is a vowel on the
other side
Confirmation bias