Re: Some brain questions i need help with

From: dan michaels (feedbackdroids_at_yahoo.com)
Date: 09/25/04 

Date: 25 Sep 2004 09:53:50 -0700

"John Hasenkam" <johnh@faraway.> wrote in message news:<4154eeff@dnews.tpgi.com.au>...

> >
> > Once, 20 years ago ???
>
> That's it, even when I tried writing down dreams to look for patterns the
> emotional content was nearly absent. For the most part I'm just grateful my
> brain can generate entertainment for me while asleep. Even last night I
> nearly got killed twice through reckless driving but no sweat I just kept
> driving like a maniac(in my younger days I nearly got killed several times
> on the bike).

Strange that there are life and death situations but no "emotion". In
my dreams, what usually wakes me up in a lurch is the high emotional
content. This week in one, someone I knew fell off a cliff to their
death, and it was such a shock that I immediately awoke in a sweat,
and somewhat shaken. Sounds pretty emotional to me. I think that's why
they call them nitemares.
=============

> What might be interesting is to contrast dreams that occur during REM and
> NREM sleep. NREM dreams are much harder to assess but there is more research
> being conducted in this area. The Hobson et al text I am reading states that
> considerable controversy still exists in regard to these two dreaming
> states. (What about day dreams, where we still are monitoring the
> environment? Not nearly as bizarre, if bizarre at all.) The authors also
> make this important point:
> Hobson et al ...
>

As Wolf was saying, all of these phenomena no doubt involve many of
the same brain regions - normal vision, daydreams, real dreams.
However, there may be other areas, like a critical faculty area which
compares current experiences to past experiences, which are turned up
or down in different contexts.
===============

> ---
>
> Some studies have indicated the exercise of being asked to recall dreams
> changes reports over time. Thus people interested in their dreams may often
> generate differing reports than those who simply remember some dreams but
> are not too interested in the exercise. The conscious attention to dreaming
> changes the reporting, I suspect it also changes the dreaming. Now that's a
> problematic confounder.
>

Gazza*** discusses the problems of real memories and false memories
in The Mind's Past, pub 1998. He and associates have been studying
brain-injured and other subjects for many years. His basic conclusion
is that "memory" is not really very good, and many things are
interpolated into so-called memories upon recall ....

"... Our brains are built to remember the gist of things, not the
details. It is as if our memory system can get us into the arena of a
past event, but it can't recall the details of the event with much
accuracy. Yet we frequently go on and on about the details as if we
truly remember them ...."

This gets back to Penfield, as we discussed earlier.

>From his many years of split-brain studies, Gazz also concludes there
is a so-called "interpreter" that resides in the LHB and doesn't exist
in the RHB, that "fills in" details. IOW, there are big differences
between LHB and RHB operation observed in split-brain individuals.

"... The interpreter-charged LB remembers the gist of the story line,
and fills in the details by using logic, not real memories. The RB,
without an interpreter, regurgitates the literal story, not one
embellished by the interpreter ... Apparently the problem with false
memories comes from the interpreter ..."
=============

> Another problem is that memory is severely degraded in sleep and just prior
> to sleep, thus making verbal recall problematic. What is remembered and
> reported may at best be a very fragmentory and misleading account of dreams:
> ...
> All of the above findings can be regarded as being caused by the failure of
> recent episodic memory (as defined by Tulving 1994) in sleep.

Yes, dream experiences fade almost immediately.
===========

> ...
> Instead of the global,
> regionally nonspecific picture of forebrain activation that has been
> suggested by EEG studies, all of these new imaging studies indicate a
> preferential activation of limbic and paralimbic regions of the forebrain in
> REM compared to waking (Braun et al. 1997, 1998; Maquet et al. 1996;
> Nofzinger et al. 1997). One implication of these discoveries is that dream
> emotion may be a primary shaper of dream plots rather than playing a
> DREAMING and the BRAIN: Toward a Cognitive Neuroscience of Conscious States
> http://home.earthlink.net/~sleeplab/bbs/BBS.html (40 of 222) [1/6/2000
> 2:48:02 PM]
> secondary role in dream plot instigation.
> ---
>

Yes, this bit about dream emotion is what I've been trying to get
across. This does not seem to be commensurate with a dead soul
hypothesis.
=================

> This validates Dan's remark that dreams have high emotional content. What am
> I then, cloned Spock?! Lester is probably correct in asserting I am
> sleeping lightly at present, hence not much REM sleep, which may explain
> lethary, poor cognition, and easy awakenings; especially since I have been
> taking the SSRI for sometime.

Ha .... each to his own, I say. If your dreams are truly dull, well
life isn't fair, is it ;-). Some of us lucky ones were born with our
own internal cinemas. We have the music. Ha!

Related to this, it's interesting that Kosslyn, who has studied mental
imagery for many years, has said that about 2% of the population
cannot produce mental imagery at all .... including it seems, some of
the most vocal psychologists who hold forth about perception.

And obviously, any chemicals which specifically target the emotional
system are gonna have an effect. Vivid emotional dreams prolly make
heavy use of serotonin pathways, the same as affected by LSD [he says,
showing his ignorance of such details].
===============

> Especially given:
> ...
> 9) There is near universal suppression of REM sleep in humans by acute
> dosage of serotonin and norepinephrine reuptake-inhibiting
> antidepressants (Gaillard et al. 1994; Nicholson et al. 1989; Vogel 1975;
> Vogel et al. 1990).
> ---
> The SSRI I am taking is also a nore reuptake inhibitor ... .
> ...
>

Ha, says he, who wrote his previous comments about serotonin before
reading this.
==================

> Continuing with Hobson et al ...
>
> In REM compared individually to delta NREM and to
> pre- and post-sleep waking (see Table 2), these authors showed relative
> activation of the pons, midbrain, anterior hypothalamus, hippocampus,
> caudate, and medial prefrontal, caudal orbital, anterior cingulate,
> parahippocampal and inferior temporal cortices (Braun et al. 1997). Based
> on their observations, the Braun group then offered the following
> speculations which are relevant to the neurology of dreaming:
> 1) Ascending reticular activation during REM as compared to waking may
> favor a more ventral cholinergic route leading from the brainstem to the
> basal forebrain over a more dorsal route via the thalamus.

This has always been of prime interest regards my conjectures about
why brain tissue tends to be so "stable" in operation, given its
monumental complexity.

In contrast, in engineering, one of the easiest things to do is to
create an unstable system, at least in situations involving feedback.
Instability in a single engineering FB loop can produce catatrosphic
results, but the brain has millions or billions of FB pathways. Ross
Ashby said organisms must be not only stable, but ultrastable,
otherwise even minor insults from without would immediately kill them.
Nature has solved a difficult problem here.
================

> 2) Activation of the cerebellar vermis in REM may reflect input to this
> structure from the brainstem vestibular nuclei. We note that these nuclei
> also constitute an important potential source of neuronal activation
> causing the unique vestibular features of fictive movement in dreams
> (Hobson et al. 1997; Leslie & Ogilvie 1996; Sauvageau et al. 1998).
>
> 3) Noting both a particularly strong REM sleep-related activation of the
> basal ganglia and the known connectivity of these subcortical structures,
> Braun et al. suggest that the basal ganglia may play an important role in an
> ascending thalamocortical activation network. They suggest that this
> network extends successively from the brainstem to the intralaminar
> thalamic nuclei, then to the basal ganglia, and back to the ventral anterior
> and ventromedial thalamic nuclei, and thence to the cortex.
> ...

Hmmm, substrate for many FB loops. Making stable is all the more
curious.
==============

> The role of the basal ganglia in the initiation of
> motor activity may, in turn, be related to the ubiquity of motion in dreams
> (Hobson 1988b; Porte & Hobson 1996).
>
> ...
> 5) The prominent decrease in the executive portions of the frontal cortex
> (dorsolateral and orbital prefrontal cortices) contrasts with the
> REM-associated increase in activation of the limbic associated medial
> prefrontal area. This medial area region has the most abundant limbic
> connections in the prefrontal cortex, has been associated with arousal and
> attention, and disruption of this area has been shown to cause
> confabulatory syndromes formally similar to dreaming. (Note also the
> dream-wake confusional syndrome associated with anterior limbic cortical
> lesions reported by Solms 1997.)
>

Emotional areas, again.
====================

> Nevertheless, it seems likely that considerable portions of executive and
> association cortex active in waking may be far less active in REM leading
> Braun et al. (1997) to speculate that "...REM sleep may constitute a state
> of
> generalized brain activity with the specific exclusion of executive systems
> which normally participate in the highest order analysis and integration of
> neural information" (p. 1190).
> ...

Which helps explain the loss of critical oversight on the part of the
"I" when inside the dreams.
====================

> Not only is REM sleep chemically biased but the preferential
> cholinergic neuromodulation is associated with selective activation of the
> subcortical and cortical limbic structures (which mediate emotion) and
> with relative inactivation of the frontal cortex (which mediates directed
> thought). These findings greatly enrich and inform the integrated picture
> of REM sleep dreaming as emotion-driven cognition with deficient
> memory, orientation, volition and analytic thinking.
>

As we've noted, from our own empirical studies in the night :). Too
bad your dreams are so dull, JH :-(.
=====================

> ...
>
> In addition to prominent thalamic deactivation, all three recent
> studies have found regional deactivation during NREM in the pontine
> brain stem, orbitofrontal cortex and anterior cingulate cortex (Braun et al.
> ...
> In a second syndrome, "visual anoneria," bilateral medial occipito-temporal
> lesions produce full or partial loss of dream visual imagery (again with
> normal waking vision).
> ---
> This suggests an important difference in Dream visual imagery and ordinary
> seeing?

Hmmm, is needing more detail here ... occipito-temporal covers a lot
of area.

And there are those 30+ visual areas, and those many interconnecting
pathways, so one imagines there are many ways that normal operation of
the system can be affected. Remember the woman of Sacks' essay who had
a lesion in MT [I think it was], and she couldn't see motion effects.
Things looked more like stopped-frame action. Or the artist with the
lesion in V4 who could not longer integrate colors into his paintings
in a coordinated way. IE, they had spcific deficits resulting from
specific lesions.
====================

> ...
>
> A second
> concern is the often reported lack of emotion-related physiological arousal
> accompanying dream events (e.g., violence) which would easily elicit such
> arousal in waking (Perlis & Nielsen 1993). Such emotional "numbing" in
> dreams could result both from a sleep-related dissociation of peripheral
> and central autonomic activity (as with peripheral arousal in Stage 4)
> combined with REM-related blockade of central readout to the periphery
> and peripheral sensory feedback to the CNS.
> ---
> Above touches on what I mentioned before about reduced affect being the
> result of agents external to the CNS.

Yes. Also, one suspects that different brain areas are more or less
inhibited during different stages of sleep and dreaming, so the
effects aren't always the same. IE, some dreams are more emotional
than others, etc.
==================

> ...
> The left dorsolateral prefrontal cortex has been shown to be selectively
> activated during human reasoning tasks (Goel et al. 1998). Its deactivation
> could account for the illogical ad-hoc explanations offered for bizarre
> occurrences (Williams et al. 1992). Similarly, the prefrontal cortices have
> been consistently shown to activate during episodic and working memory
> tasks (Brewer et al. 1998; Courtney et al. 1997; Cohen et al. 1997; Fletcher
> et
> al. 1997; Tulving et al. 1996; Wagner et al. 1998); their deactivation in
> REM
> may contribute to the prominent mnemonic deficits in dreaming noted
> above in Section II.C.4.
> ---
>
> > In fact, I suspect that highly-emotional dreams and sweating happens
> > very frequently. At least it does to me. Most of the time you just
> > don't wake up, or else you wake up too late to remember the dream.
> > Occasionally, if there is a lot of emotional content, I wake up
> > "quickly" enuf to remember it.
>
>
>
>
> > Dreams have different levels of emotional content, rarely do I have
> > what you have described as a nitemare, but many dreams do involve
> > plenty of emotion, people dying, etc. I just assume it's one part of
> > the dream phenomenon, and don't get rattled about it. It's just
> > made-up.

Bottom line.