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Behavioral Neuroscience

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Transcranial Magnetic Stimulation (TMS) Cognitive Neuroscience STRUCTURAL Neuroimaging CT (Computerized Tomography) MRI (Magnetic resonance imaging) ... – PowerPoint PPT presentation

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Title: Behavioral Neuroscience


1
Behavioral Neuroscience Neurology
  • Lesion studies
  • Animals
  • Patient case studies
  • Phineas Gage
  • H.M.
  • Single cell recordings
  • Behavioral studies
  • TMS (Transcranial Magnetic Stimulation)
  • Creating artificial temporary lesions in the
    brain

2
Transcranial Magnetic Stimulation (TMS)

3
Cognitive Neuroscience
  • STRUCTURAL Neuroimaging
  • CT (Computerized Tomography)
  • MRI (Magnetic resonance imaging)
  • 3-D combine x-ray or MRI slices
  • FUNCTIONAL Neuroimaging
  • EEG (Topography) 1929
  • MEG (Magnetoencephalogram)
  • PET (Positron Emission Tomography 1970s)
  • cerebral glucose levels
  • high spatial resolution but low temporal and
    invasive
  • fMRI (functional MRI) 1990s

4
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5
functional Magnetic Resonance Imaging (fMRI)
  • Measures cerebral hemodynamic response (BOLD
    signal)
  • Blood flow in brain levels of oxygen in
    (deoxy)hemoglobin recruited by firing neurons
  • Structure AND function in single scan
  • High spatial resolution with modest temporal
    resolution
  • Problem loud scanner noises, machine artifacts

6
MRI physics
7
Conventional MRI
white matter
gray matter
  • MRI is sensitive to myelin

8
HIGH Spatial Resolution of MRI
Histology
MRI
Layer IV
9
MRI vs. fMRI
MRI - shows difference between different types of
tissues (difference in space, e.g. white vs.
gray matter)
  • fMRI
  • shows difference between stimulated and
    non-stimulated tissue (difference in time)

10
What is functional MRI (fMRI)?
Stimulus Off (Condition 1)
T2 (tissue at rest)
MR signal
time
fMRI detects subtractive difference in signal
(?S Cond. 2-Cond.1) fMRI is indirect
(hemodynamic) method of cellular communication
11
Structural MRI Functional MRI
Anatomical MRI (T1-weighted)
12
Spatio - temporal scales
MEG / EEG
Spatial Resolution (mm)
PET
fMRI
Single / Multi Unit Recording
1 msec 1 sec 1 min
10 min 1 hour
Temporal Resolution (sec)
  • Why fMRI?
  • non-invasive gt can be used in humans
  • measures population neural activity
  • can study whole brain at once

13
MRI scanner
  • Magnetic field
  • is VERY STRONG ( 3T 30,000 times the earths
    magnetic field)
  • is ALWAYS ON

14
Image Artifacts and Subject Safety
15
Typical fMRI experiment
Stimulus
Stimulus
Stimulus
Stimulus
Off
Off
On
On
(30 s)
(30 s)
(30 s)
(30 s)
.

.

.
  • Stimulus (e.g. music) is presented to subject
    repeatedly every 30 sec.
  • Images are acquired 2 sec.

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16
Scanner Noise
  • Scanner noise sources
  • scanner cooling system (ongoing)
  • gradient coils (every image acquisition)
  • Noise is a PROBLEM
  • want response to stimulus, get response to
    stimulusscanner noise
  • scanner noise reduces dynamic range of response
  • scanner noise masks stimulus
  • Solutions
  • blocking noise transmission to the subject
    (earplugs, earmuffs)
  • modifying scanner
  • modifying experiment

17
Subcortical Activation
MGB
IC
SOC
CN
18
Inferior Colliculus
(sound intensity varied)
75 dB SL
55 dB SL
35 dB SL
Inferior Colliculi
1
19
Auditory Cortex
auditory cortex
20
Millisecond changes in electrophysiology (ERPs)
21
Functional Neuroimaging Resolution
Spatial Temporal
EEG/MEG 1-3 cm2 1 ms
PET 3 mm3 20 s ( 3-8 s lag)
fMRI 1 mm3 2 s ( lag of 3-8 s)
22
Dis/Advantages of each technique
23
Mind vs Brain
24
  • VHS 1518.25 Dr Phil- Cognitive Neuroscience
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