The Salience Network

  • The Salience Network

    Posted by Whit Blauvelt on May 26, 2023 at 5:01 pm

    The top-down, “superior” view in this illustration shows the default mode network (daydreaming, prospection, empathy) correlating more with the right hemisphere, and the frontoparietal (aka task mode) network correlating more with the left hemisphere. These are from the article “The role of the salience network in cognitive and affective deficits” (https://www.frontiersin.org/articles/10.3389/fnhum.2023.1133367/full). The salience network, in the model the article supports, is as switch between the two. Trouble in switching correlates with many of the conditions McGilchrist addresses with the hemispheric hypothesis. This leads to the question of whether the hemispheric hypothesis and the triple network model described in this paper are essentially congruent.


    Don Salmon replied 4 days, 10 hours ago 2 Members · 2 Replies
  • 2 Replies
  • Whit Blauvelt

    Member
    May 27, 2023 at 8:55 pm

    On a general level, the Triple Network Model and the Hemispheric Hypothesis suggest a shared set of questions, both in for what might be found objectively of brains, and subjectively for ourselves. If McGilchrist is right about our culture promulgating a mentality where the emissary (whether seen as LH or as task-mode network) has run away and is no longer properly contextualized by the master (whether seen as RH or as default-mode network), is this primarily:

    1. The LH is hyperactive over time — truly a run-away state?

    2. The RH is hypoactive?

    3. The if either of those, is it a flaw internal to the LH or RH (such as the cases of organic damage to the RH McGilchrist catalogs)?

    4. Or is there, between these, something like the switch which this paper is calling the “salience network,” and is the switch stuck?

    5. If the switch is stuck, is that stuckness internal to the switch, or to yet other factors which should toggle it (or fail to)?

    6. Whereas McGilchrist — and the myths he cites — more blames the emissary for running away, since the sense of self is more in the RH (and the default-mode network — both are supported by evidence) then might the fault be more in a flawed sense of self — and perhaps an attempt at escape from that into an over-tasked life? Is the LH really running away, or is the RH too often deserting its station?

    7. Can we identify aspects of these two hemispheres and/or three networks (or two plus switch) introspectively, and move our internal focus of attention between them, so as to tune their relations (and/or adjust the switch) from the inside?

  • Don Salmon

    Member
    May 31, 2023 at 1:53 pm

    That’s an interesting take on the default network.

    In most of the studies I’ve seen as well as large-scale summaries, the default network is characterized by negative mind-wandering, often seen as triggered by survival-related fears.

    In more recent writings, I’ve seen more references to the so-called “positive” states you reference, creative day-dreaming etc.

    I might speculate on how one might involve one hemisphere more than the other, but actually, I was wondering if parapsychological research as well as various brain injuries might shed some light on the relationship of the hemispheres.

    On the one hand, we know from over a century of psi research that it is perfectly possible to perceive objects without the use of the brain.

    On the other, McGilchrist himself makes reference to the case of several individuals who were born with or had injuries resulting in the complete absence of one functioning hemisphere, who yet had all the psychological characteristics (narrow detached attention vs wide, open immersed attention) of those with two hemispheres.

    I think the problem we get into is that McGilchrist himself, as he also has acknowledged numerous times, alternates, often without acknowledging it in the moment, between discussion of the hemispheres as metaphorical and discussion of them as literal. I find in many of the discussions on this channel, LH and RH are referred to as if they are discrete entities, and on the verge of assuming they control consciousness rather than are vehicles for it, or perhaps more accurate, simply reflect – as does all matter – activities of consciousness.