Reptilian Brain

[wenshu]

The brain model of triune is still somewhat accepted.

With survival insitinct and motor skills, involuntary maintenance being attributed to the "reptilian complex" and the limbic system while social skills and higher thinking being given to the neo-cortex which is the large outer layer of the brain.

These days, knowledge of teh brain and it's function changes with every publication of the Lancet or journal of neuroscience though it seems.

There have been instances of damage to the so called "limbic" system that resulted in higher cognitive dysfunction.

Even the limbic distinction is being challenged.

If it is still accepted, it isn't by neuro-scientists.

[David Jamieson]

There have been instances of damage to the so called "limbic" system that resulted in higher cognitive dysfunction.

Even the limbic distinction is being challenged.

If it is still accepted, it isn't by neuro-scientists.

mmm, I said somewhat, as in, there clearly are three physical and different layers to the brain.

what they do, is also "somewhat" known.

[David Jamieson]

thats pretty sweet if you can be all that without any conflict at all... good on ya, i say... i wasnt asking to rail at you about it or anything...



ok so are the most basic functions in the center or bottom or isolated somewhat and as it grows outward the more complex functions are formed??? as the brain got bigger it grew in a sort of layers as opposed to getting bigger and more complex all the way thru??? do you guys know what im asking? i am no med student, im not sure of the proper terminology to phrase my question...

my knowledge comes from psych class. I'm not a med student either I just wanted to spend 9 months analyzing myself and then a couple of more years alienating my friends by telling them what was wrong with them.

anyway... there is still a lot of theory as to how we came about having this lump of magnificent jelly inside our skulls.

I heard one that said our brain grew from our intake of sea food at the same time as we lost our thickness in our hair from being in the water a lot for protection. (we still have the same and in some cases superior follicle count to most primates.)

Also, the dna and cells that we exchanged for the brain used to be our tails.

But who knows. Could of all be done in a flash of light by a fish with a beard right?

[Syn7]

my knowledge comes from psych class. I'm not a med student either I just wanted to spend 9 months analyzing myself and then a couple of more years alienating my friends by telling them what was wrong with them.

anyway... there is still a lot of theory as to how we came about having this lump of magnificent jelly inside our skulls.

I heard one that said our brain grew from our intake of sea food at the same time as we lost our thickness in our hair from being in the water a lot for protection. (we still have the same and in some cases superior follicle count to most primates.)

Also, the dna and cells that we exchanged for the brain used to be our tails.

But who knows. Could of all be done in a flash of light by a fish with a beard right?

oh look, another psych dropout... how unique...


tails huh... interesting... all i know about the brain is stuff from magazines and documentaries... well, and limited anatomy from highschool, if you even want to count that... ive learned 5 times as much just by paying attention since then

[David Jamieson]

oh look, another psych dropout... how unique...


tails huh... interesting... all i know about the brain is stuff from magazines and documentaries... well, and limited anatomy from highschool, if you even want to count that... ive learned 5 times as much just by paying attention since then

well, when you want to learn there is a whole different thing going on than when you have to...

and all that.

[wenshu]

mmm, I said somewhat, as in, there clearly are three physical and different layers to the brain.

what they do, is also "somewhat" known.

neuroanatomy fail.

[David Jamieson]

neuroanatomy fail.

you disagree?

The r-complex, the limbic system and the neo-cortex are no longer recognized?
How so?

I mean, names change and functions get discovered, but:


There's halves and individual parts, but still seems to be the three layers going on.
So...

[wenshu]

you disagree?

The r-complex, the limbic system and the neo-cortex are no longer recognized?
How so?

I mean, names change and functions get discovered, but:


There's halves and individual parts, but still seems to be the three layers going on.
So...

Where did you get that outdated, over-simplified abstraction? A 30 year old community college popular psychology 101 textbook?

The structures of the forebrain have a far more complicated relationship with the higher cognitive functions traditionally ascribed solely to the neocortex; the brain does not function as some top down hierarchical abstraction.

One World, Many Minds: Intelligence in the Animal Kingdom
Scientific American Dec 2008


Many people believe that a component of the human brain inherited from reptilian ancestors is responsible for our species’ aggression, ritual behaviors and territoriality.

One of the most common misconceptions about brain evolution is that it represents a linear process culminating in the amazing cognitive powers of humans, with the brains of other modern species representing previous stages. Such ideas have even influenced the thinking of neuroscientists and psychologists who compare the brains of different species used in biomedical research. Over the past 30 years, however, research in comparative neuroanatomy clearly has shown that complex brains—and sophisticated cognition—have evolved from simpler brains multiple times independently in separate lineages, or evolutionarily related groups: in mollusks such as octopuses, squid and cuttlefish; in bony fishes such as goldfish and, separately again, in cartilaginous fishes such as sharks and manta rays; and in reptiles and birds. Nonmammals have demonstrated advanced abilities such as learning by copying the behavior of others, finding their way in complicated spatial environments, manufacturing and using tools, and even conducting mental time travel (remembering specific past episodes or anticipating unique future events). Collectively, these findings are helping scientists to understand how intelligence can arise—and to appreciate the many forms it can take.

The Tree of Life
To understand why a new view of the evolution of brains and minds is only now coming to full fruition, it is useful to review historical notions. Medieval naturalists placed living things along a linear scale called the great chain of beings, or scala naturae. This hierarchical sequence ranked creatures such as worms and slugs as lowly and humans as the highest of earthly beings. In the late 1800s the enormous mass of evidence contained in Charles Darwin’s masterwork, On the Origin of Species, convinced most of his scientific contemporaries that evolution was a reality. Darwin explained that modern species were related by physical descent and saw the relations among species as resembling the diverging branches of a family genealogical tree. Few, however, fully grasped the revolutionary implications of this tree of life—in which modern species represent the tips of the branches and inner branches represent past species, forming junctions where two lineages branch from a common ancestor.

So when comparative neuroanatomy first blossomed at the end of the 19th century, most researchers interpreted its findings in terms of the old linear scale. They believed modern invertebrates (animals without backbones), fish, amphibians, reptiles, birds, mammals and humans to be living representatives of successive evolutionary steps toward a more complex brain, with new brain components added at each step. Given the relative lack of interest in comparative neuroanatomy during the mid-20th century, these ideas persisted unchallenged for decades. The traditional ideas about sequential brain evolution appeared, for example, in the late neuroscientist and psychiatrist Paul D. MacLean’s triune brain model, formulated in the 1960s. Mac*Lean’s model promoted the belief that the human brain contains a “reptilian complex” inherited from reptilian ancestors.

Beginning in the 1980s, the field of comparative neuroanatomy experienced a renaissance. In the intervening decades evolutionary biologists had learned a great deal about vertebrate evolutionary history, and they developed new and effective methods of applying Darwin’s concept of the tree of life to analyze and interpret their findings. It is now apparent that a simple linear hierarchy cannot adequately account for the evolution of brains or of intelligence. The oldest known multicellular animal fossils are about 700 million years old. By the Cambrian period, about 520 million years ago, the animal kingdom had branched into about 35 major groups, or phyla, each with its own distinctive body plan. As a separate branch of the tree of life, each lineage continued to evolve and diversify independently of the others. Complex brains evolved independently in multiple phyla, notably among the cephalopod mollusks of the phylum Mollusca and, of course, among various groups of vertebrates. Vertebrate evolution has likewise involved repeated branching, with complex brains evolving from simpler brains independently along numerous branches.

[wenshu]

The limbic system: a review of its empirical foundation
Rolf Kotter and Niels Meyer

The limbic system is not a piece of nature given to
us. It is just one out of many scientific concepts. From
an empirical point of view this concept is not adequate
and there is nothing to justify its continuing use in a
general and indiscriminate sense.
Other and better scientific concepts have to be put
forward and to be considered. The analysis of Medline
shows that the limbic system does not constitute the
only explanatory concept in respect to the brain struc-
tures and functions involved in the limbic system. For
example the hippocampus and with it the functions of
memory have to a large extent emancipated from the
limbic system concept, and we may believe that we
begin to understand them to some extent. The hypo-
thalamus, some olfactory structures, and the gyrus cin-
guli remain more closely linked to the limbie system and
with them the workings of emotions, the presumably
primitive and savage functions ofolfaction, and the key
concepts to their surgical control. These areas seem to
be far more puzzling. It is of interest to note that the
limbic system represents particularly those areas in
brain research which are poorly understood.
It may turn out that the limbic system becomes more
and more obsolete as our knowledge increases. But so
far it has a very important role to play: it meets our need
and desire for explanatory concepts in the neuro-
sciences which is reflected in the influence that the lim-
bic system has on many areas in the neurosciences. The
reasons for its explanatory power cannot be found in
its empirical foundation. But there are other non-
empirical features which we should be aware of and
which repeatedly occur in many of the different crite-
ria which we have listed. The concepts of the closed
circuit, of the balanced functions, and of the hierarchi-
cal processing are prominent. The corresponding sym-
bols of the circle, the balance and the ladder have served
for a long time in explaining the unexplained. It is no
accident that the greatest mysteries in our understand-
ing of the brain remain with the limbie system: ques-
tions concerning the integration of all brain functions,
the generation of consciousness or psyche, and finally
the seat of the soul. The struggle with these questions
has found an expression in the multi-faceted and con-
troversial concept which is called the limbic system.
"The term, however, is simple and enjoys universal
recognition: everyone thinks he knows what is meant
when he hears it ''7z.

[David Jamieson]

Well, I can only guess that the journal of neuroscience, neuroscience in general and other various publications for the field of neuroscience are negligent in keeping information up to date?


I'm a reader.

And everything you just quoted tells me there is still a lot of sniffing around going on and very little in the way of certainty about this. Lots of theory and concepts and some in conflict...

Meh, as long as they can stop bleeding, remove foreign objects and close the wound and healing takes place, that's good enough.

[Syn7]

well, when you want to learn there is a whole different thing going on than when you have to...

and all that.

yeah i dropped out in grade 9 and went back when i was 17 and did the rest of 9 10 11 and 12 in less than a year and a half at self paced school... but its a regular diploma, none of that ged or adult dogwood bullsh1t... when i was in real HS i was like a c+ student, which was pretty good since i had like 30% attendance... but my final transcripts are high B's and A's... so yeah, i'd say wanting to be there makes the difference...

[bawang]

yeah i dropped out in grade 9 and went back when i was 17 and did the rest of 9 10 11 and 12 in less than a year and a half at self paced school... but its a regular diploma, none of that ged or adult dogwood bullsh1t... when i was in real HS i was like a c+ student, which was pretty good since i had like 30% attendance... but my final transcripts are high B's and A's... so yeah, i'd say wanting to be there makes the difference...

you are a man of great honor. you must have very hairy chest and pubis

[TenTigers]

the dna and cells that we exchanged for the brain used to be our tails.

well, that explains alot about alot of people....

"used to ...?"

[Lucas]

I didnt trade mine in, I use my tail for climbing and other stuff.