Connectivity and Brodmann Area Functions

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Connectivity and Brodmann Area Functions

• Roger J deBeus PhD David A Kaiser PhD

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The more neurons recruited into a rhythm, the
higher the spectral magnitude

• Spectral magnitude proportion of neurons in the
  functional group (rhythm)

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Generation of spindles (7-14 Hz)

• Length of inhibitory potential sets the frequency
  (which is mediated by GABA type A receptors) .
  The potential determines the time until another
  burst of spikes is generated by the TC neuron
  (Franks, 2008)

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Activity and Connectivity
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Network disturbance
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Connectivity involves callosal connections and
ipsilateral pathways

• Four types of cortico-cortical projections
• 1) homotopic, 2) homoareal, 3) heterotopic, and
  4) ipsilateral

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How shared is (frequency) information?

• Coherence
• (Wiener, 1930 Goodman, 1957 Walter, 1961)
• Comodulation
• (Pearson, 1896 Kaiser, 1994)

Coh values from 0.0 to 1.0 Comod values
from -1.0 to 1.0
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Phase lag between two signals indicates time
delay between brain areas recruited into the same
operations (rhythm)
Out of phase (180 degree lag) In
phase (0 degree lag)
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Signals are

• coherent when phase difference is stable

• comodulated when magnitude difference is stable

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Data (rho) and Statistical (z) values
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Orient ones reading by the fixed points each
site is compared to itself in each head
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Autistic child, replicated EC
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Hypermodulation of depression
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Shared information between two signals

• Magnitude
• Mean consistency (comodulation)
• Mean difference (asymmetry, unity)

• Phase
• Mean consistency (coherence)
• Mean difference (phase lag)

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Network Maps (anterior callosotomy case
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Functional clots as sources of dysfunction,
i.e. abnormal dis/engagement of one or more
cortical networks.
Activity Connectivity
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BRODMANN AREA FUNCTIONS
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Brodmann areas Brain areas based on
cytoarchitecture
Korbinian Brodmann (1868-1918)
(1906) - 52 primate cytoarchitectonic brain areas
(47 human)
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• Phrenology
• (27 mind-skull correspondences)
• Impulse to propagation
• 2. Parental love
• 3. Fidelity
• 4. Valor
• 5. Carnivorousness
• 6. Sense of cunning
• 7. Sense of property
• 8. Love of authority
• 9. Vanity
• 10. Circumspection
• 11. Memory of facts
• 12. Sense of locality
• 13. Recollection of persons
• 14. Faculty for words
• 15. Faculty of language
• 16. Delight in colors

Franz Joseph Gall (1758-1828)
Associating variations in character with
craniological signs.
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Frontal lobe damage impacts emotional regulation,
however acquired
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Cortical Lobes
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Primary functions
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LORETA Low resolution EEG tomographical array
Source Imaging
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Electrode placements for ideal head (Talaraich
space)
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Orbitofrontal 11,47Dorsolateral 8-10, 44-46
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Dominant Frequency by Brodmann Area
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Based on 1,000 fMRI studies
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(No Transcript)
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Hyperconnectivity with (right) cingulate in
Autistic children- indicates impaired mirror
neuron system?
Subcortical hyperconnectivity may reduce
cortico-cortical connectivity
E.g., Mizuno et al. (2006). Partially enhanced
thalamocortical functional connectivity in
autism. Brain Research, 1104 160-74.
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Reduced right inhibition of motor system in ADHD