<p></p><p>THREE KINDS OF CONNECTIVITY</p>

<p><!--[if !supportLists]-->1)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
<!--[endif]-->Structural – anatomical connectivity DTI/DSI</p>

<p><!--[if !supportLists]-->2)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
<!--[endif]-->Functional Connectivity</p>

<p><!--[if !supportLists]-->3)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
<!--[endif]-->Effective connectivity</p><p>&nbsp;</p><p><i>Human intelligence is directly correlated to brain
complexity as measured by the EEG (Anokhin et al, 1999; Giannitrapani, 1985;
Thatcher et al, 1983; 2005)</i></p><p><i><br></i></p><p></p>

<h2><a name="_Toc29929042"></a><a name="_Toc3535256">Coherence</a></h2>

<p>&nbsp;</p>

<p>Coherence is generally thought of as connectivity.&nbsp;<span style="font-size: 1rem;">There is a two compartmental level model of
coherence. Coherence is cortical-cortico connectivity.</span><span style="font-size: 1rem;">When cortical-cortico connections are cut, this
does not affect coherence! Coherence is Cortical-thalamo-cortical.</span></p>

<p><a name="_Hlk488301210"></a><a name="_Hlk523304243"></a><a name="_Hlk491673952">The measure of coherence is the measure of
the stability of the phase relationship between different sites in the brain.
That is to say, we are measuring connectivity from the perspective of
flexibility.&nbsp; </a>Hypercoherence
shows a lack of flexibility in the connection relationships; firings are locked
into the same rhythm. Imagine
soldiers goose-stepping or a crowd clapping in unison. Hypercoherence is
problematic in the sense that it can create “tunnel vision” or the inability to
switch tasks readily. On the other hand, it may lead to a sort of frenetic
distractibility, where nothing gains the complete attention and the individual
always feels “scattered,” “distracted,” and busied.</p>

<p>Coherence is stability of the phase relationship in the
brain. Hypocoherence is a lack of stability, in terms of the brain waves never
remaining consistent in their relative relationship to other areas of the
brain. Hypercoherence is an “over-connectivity,” or the stability of the phase
relationship between the areas of the brain are in a locked pattern.</p>

<p>For example, hypocoherence, as we see in the delta range and
at the sites of C4 and P4 (the axis of the sensory part of the sensory motor
strip and the superior parietal lobe), is a deviance in phase relationship in
the sense that the affected site is not cooperating or coming into any reliable
relationship with any of the surrounding areas.&nbsp;
In these maps, C4 (correlating with Brodmann areas 3, 4, 5, and 7) and
P4 (correlating with Bas 5 and 7) area those areas committed to visuospatial
functions motor imagery and processing, memory (working memory and visuospatial
memory), language processing (attention to sentence comprehension and
phonological relations) and even the processing of emotion ( 5 and 7), as well
as motor movements, the control of motor tasks, kinesthetic perception of limb
movement, contralateral lower limb movement, and the localization of pain,
temperature, vibration, and touch (Bas 3 and 4).</p>

<p><a name="_Hlk523384356">Hypercoherence is an
“over-connectivity,” or the stability of the phase relationship between the
areas of the brain are in a locked pattern. In this case, there is a
preponderance of alpha activity with the eyes closed (partially due to
medication), and in this state we also see the 9-12 Hz bandwidth come into a
“locking” of sorts. </a>Alpha synchrony (or hypercoherence) is often seen in
meditators, and it shows (often) a certain presence about the individual.
Feeling alert and “here and now.” This is, for the time being, not the primary
concern, especially since the client reported becoming drowsy with the eyes
closed state.</p><h3><a name="_Toc29929044">Asymmetry</a></h3>

<p><a name="_Hlk523168956">Asymmetry is a reflection of a power
differential in the brain, that is to say, the lines coming from the back of
the head in the above picture represent an excess of energy that lives
occipitally. As the excessive power in the occiput diminishes, so will the
reflections of asymmetry in amplitude.</a></p>

<p>&nbsp;</p>

<h2><a name="_Toc29929045">Phase</a> </h2>

<p>The phase measures have also been normed. It is clear that
phase is an important measure in understanding propagation of neuronal
activity. Progressive phase delays are measurable as a volley travels from a
source to a destination. In addition, 180 degree differences in phase denote
polarity inversion and suggest the location of underlying generators. Using
polarity inversion to model the source of brain macropotentials is useful in
localizing activity and is commonly used in electroencephalography (Niedermeyer
and Lopes da Silva, 1999). However, the meaning and utility of measures of
“average phase” over time is not as clear.</p><p>Click <a href="https://vimeo.com/443082983">"here"</a> to watch a video on phase shift and phase lock.&nbsp;</p><h3><a name="_Toc29929046">Phase Shift, Phase Lock, and Phase Reset</a></h3>

<p>For 200 – 1,0000 msec clusters of neurons assemble into phase
synchrony (aka “phase lock”); conversely, for 200-1,000 msec clusters of
neurons disassemble into loss of phase synchrony (aka “phase shift”).&nbsp; The dominant acting force for these
synchronizatons and desycnhronizations&nbsp;
is that of stochastic resonance (“stochasm” is latin for “purposeful
randomness”).</p>

<p>Phase reset is made of phase shift and phase lock, which is the
synchronization and desynchronization of neurons. Phase shift is like a “shout
out,” where neurons are recruited to synchronize with the action potential
activity at the time.</p>

<p>&nbsp;Thatcher et al. (2008)
identified that longer phase shift dynamic is related to superior I.Q., with an
optimized balance between phase shift and phase lock being ideal. &nbsp;Phase shift duration is related to the average
local inhibitory post synaptic potential duration on cell bodies and the phase
lock duration is positively related to the average excitatory post synaptic
potential summation on the dendrites of cortical pyramidal cells.</p>

<p>When <u>phase shift duration is too short</u> then there are fewer
neural resources available to be phase locked into a stable dynamic. <u>Longer
phase shift</u> duration increases the probability of identifying larger
numbers of neurons capable of being phase locked (this is why there is a direct
relationship between shift duration and I.Q.). However, when <u>phase shift
duration is too long</u> then there is increased noise and reduced number of
neurons available for phase locking. When <u>phase lock duration is too long</u>
then there is less flexibility and there are reduced resources available to be
allocated by the phase shift mechanism.&nbsp;However, <u>too short of phase
locking</u> will result in less information processing and less efficiency of
the allocated resources with premature release of the resources by a subsequent
phase shift. &nbsp;In short, an optimal
balance between phase shift duration and phase lock duration is related to
higher levels of intelligence because of an optimal balance results in maximum
speed and efficiency of information processing.<b>&nbsp;</b></p>

<p>The dynamic balance between synchronization and desynchronization
is essential for normal brain function and abnormal balance is often associated
with pathological conditions such as epilepsy (Lopes da Silva and Pihn, 1995;
LeVan Quyen et al, 2001b; Chevez et al, 2003; Netoff and Schiff, 2002),
schizophrenia (Lee et al., 2002) and dementia (Stam et al., 2002a; 2002b).</p>

<p>Phase dynamics are represented in Bob Thatcher’s qEEG analysis as
the metric of “Phase Lag.” Phase lag can be normal (no lines presented), hyper
phase lag (red lines) or hypo phase lag (blue lines). Hyper phase lag indicates
<i>too much phase lag</i> and not enough phase synchrony (i.e. not enough phase
lock). This can result in increased neuronal noise and a reduced amount of
neurons available for phase locking.</p><h3><a name="_Toc29929047">Hyper Phase Lag in Theta in a 60-year-old
man complaining of memory difficulties</a></h3><p style="text-align: center; "><a name="_Toc29929047"><img src="@@PLUGINFILE@@/Hyper%20Phase%20Lag.png" alt="Hyper Phase Lag" width="626" height="454" class="img-responsive atto_image_button_middle"><br></a></p><p><a name="_Toc29929047"><br></a></p><p><a name="_Toc29929047"><br></a></p><p><br></p><p><a name="_Toc29929047"></a></p><p><a name="_Toc29929047">Hypo phase lag indicates not enough phase lag (and too long phase
lock) indicating that neuronal assemblies are coming into synchrony too
frequently and for longer duration than is ideal. The individual in the
following image report difficulty keeping attention on any given task.</a></p><p></p><h2><a name="_Toc29929048">Hypo Phase Lag in all Frequencies in a
12-year-old girl who has poor organization skills, focus and concentration</a></h2><br><p></p><p style="text-align: center;"><img src="@@PLUGINFILE@@/Hypo%20Phase%20Lag.png" alt="Hypo Phase Lag" width="528" height="384" class="img-responsive atto_image_button_middle" style="font-size: 1rem;"></p><p></p><p></p>