Brain Physiology, Cognition and Consciousness: topic
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Visual Consciousness: Too Many Neural Correlates?
Alfredo Pereira Jr
Tuesday, 22 April 2008 13:17 UTC
Three recent publications (Del Cul et al., 2007; Melloni et al., 2007,
and Quiroga et al., 2008) present a wealthy of psychophysical data,
creating an ‘embarass de richesse” in the study of neural correlates
of visual consciousness.
A first controversy, derived from a comparison of the results, is if
conscious processing is supported by sparse activity (increase of
spike rates in relatively few neurons) or by the excitation of large
neural assemblies. A second controversy is if consciousness is based
on dendritic activity (synchronous oscillations of post-synaptic
potentials, as – roughly – recorded by the EEG) or axonal activity
(neuron firing, as recorded by single and multi-unit recordings). A
third controversy is if visual consciousness is generated by a earlier
synchronous phase (around 80-130 ms after stimulus onset) or later
ones (above 270 ms after stimulus onset).
The possible existence of too many correlates of visual consciousness
requires theoretical integrative work to solve apparent conflict and
create a new synthesis of results. In this review, after briefly
noticing the most relevant results, I summarize a chronology of brain
events correlated to conscious visual processing.
The study of visual consciousness in cognitive neuroscience is based
on establishing correlations between three parameters: properties of
visual stimuli, brain activity and the conscious state of the subject.
Del Cul et al. (2007) used a new methodology to sharpen the control of
visual stimuli: the presentation of supraliminar stimuli combined with
backward masking. The main goal was to find the sequence of brain
events necessary for the formation of a reportable conscious visual
state. The target stimulus consisted of a single digit (a number)
projected for 16 ms (a brief, but supraliminar stimulus). The mask was
a group of numbers projected soon after, for 250 ms, at the same
visual location. The authors varied the time interval (called SOA,
“target-mask stimulus onset asynchrony”) between stimulus onset and
the presentation of the mask, from 16 to 100 ms. Shorter intervals
were predicted to cause backward masking of the stimulus (basically,
relegating the stimulus below the threshold of consciousness), by
means of a perturbation of the sequence of brain events necessary to
generate the corresponding conscious state. Longer intervals would not
perturb the brain processing of the stimulus, allowing the propagation
of excitation to higher cortical areas.
High-density event-related potential (ERP) recordings were collected
to determine whether a change (or a “transition”) in brain activity
occurred between the lower and higher SOA values. The temporal
location of this transition was defined behaviorally, using two
measures: a forced-choice comparison of the presented digit with
another one (checking for both sub- and supraliminar perception), and
a scale of visibility, which assesses the conscious access to the
stimulus. This methodology produced several behavioral and
physiological (ERP) results. Behaviorally, a “significant
nonlinearity” was found for the SOA interval from 33 to 66 ms. Below
16 ms, the performance was at chance level, suggesting that the
presented digit was completely masked by the second. In the 16-33 ms
interval, performance in the forced-choice task was above chance,
while in the 33-66 ms interval both the forced-choice and the
(conscious) visibility ratings increased non-linearly. Above 66 ms
there was not a significant change in visibility and the subjects
consistently had conscious access to the presented stimulus.
The authors looked for ERP components temporally correlated with the
transition in visibility elicited by the 50 ms SOA. Using statistical
testing across subjects, they found activity within a fronto-parieto-
temporal network to be strongly correlated with the non-linear
increase in visibility. The activity that correlates with the
transition occurs about 270 to 300 ms after target onset. This finding
is consistent with the hypothesis that conscious access to a visual
stimulus involves the sequential activation of several cortical
areas.
The second study (Quiroga et al., 2008) has similarities and
differences in methodology with Del Cul. et al. One of the differences
is that Quiroga et al. made single and multi-unit recordings
(measurement of axonal activity by means of invasive microelectrodes
implanted in epilepsy patients), while Del Cul et al. used ERP. The
second difference is that Del Cul et al. measured neural activity
(including both dendritic and axonal signals) in the whole cortex,
while Quiroga was restricted to axonal firing in the medial temporal
lobe. The third difference is that Del Cul et al. presented simple
stimuli for a minimal supraliminar perceptual time duration (one digit
number for 16 ms) while Quiroga presented complex stimuli for longer
and varied times (pictures of faces and buildings during 33 to 264
ms).
The fourth (and central) difference is that the stimulus and mask
durations varied in the Quiroga experiment (while keeping the total
time of stimulus and mask presentation at 500 ms), while Del Cul
varied the time interval between them. In the Del Cul et al.
experiment the frontal response was abolished by shorter time
intervals between stimulus and mask (in this case, there was only
subliminar perception). The Quiroga et al. methodology does not allow
the usage of the masking procedure to check the necessity of medial
temporal responses for visual consciousness (they assume that the
masking procedure only affected occipital visual areas, allowing them
to rule out a crucial role of these areas for visual consciousness).
The results seem to be compatible, because the medial temporal
response measured by Quiroga (at approximately 300 ms after stimulus
onset) occurs simultaneously with or soon after the frontal response
measured by Del Cul et al. (at 270-300 ms). There are, of course,
several possible interpretations of this compatibility:
a) both responses (frontal and medial temporal) occur at the same time
and both support visual consciousness equally. In this case, the key
question is: how does the firing of one or few neurons relate to the
activity of a large synchronized assembly?
b) one of the responses occur first and supports visual consciousness;
the other serves to another function (e.g., the Del Cul et al.
response may be related to short-term memory and the Quiroga et al.
response may be related to triggering the formation of long-term
memory).
Adding to this wealthy of data, another experiment – conducted by
Melloni et al. (2007) – showed an early transient phase, described as
“long-distance synchronization of gamma oscillations across widely
separated regions of the brain”. This synchronized phase occurred from
80 to 120 ms after stimulus presentation. The problem that emerges
from a comparison with Del Cul et al. is if consciousness of the
stimulus really occurred simultaneously to the early synchronization,
since Del Cul et al. discovered that a similar stimulus takes at least
270 ms to be consciously perceived.
Melloni et al. (2007) recorded the EEG during a delayed matching to
sample task in two conditions: the target stimulus, a word – presented
for 33 ms – was preceded and followed by a mask – during 67 ms for
each presentation. The experimenters provided variations in luminance,
that rendered the stimulus visible or invisible (but still processed).
The matching with another word was performed 533 ms after the
presentation of the target. Visible words were correctly recognized in
94,5% of the cases, while the recognition of invisible words was at
chance level (52,2%). However, the behavioral measurement did not
check for conscious perception at the time of the early synchronized
phase; this correlation was induced from the fact that such a phase
only occurred for visible words (for a more accurate description of
the position of the authors, the discussion section of the paper
should be consulted).
A different interpretation of the result could be that the early
synchronous phase is necessary to prepare the conscious visual state,
but this state is completed only later. In this case the early
synchronization would have the function of priming the visual system
for further events. Physiologically, this priming corresponds to a
post-synaptic potentiation process that has to be sustained for a
longer time to participate in the conscious process (see the idea of
“meta-potentiation” proposed by Pereira and Furlan, 2007).
A theoretical integration of results from the three above
papers is actually very complex, for a series of reasons. Synchrony
refers primarily to the oscillation of post-synaptic potentials, but -
as a consequence of local oscillatory synchrony – synchronized firing
can also occur. Such a synchronous firing may be necessary to
broadcast local patterns to other parts of the brain, since the
integration of information required by the conscious process possibly
requires the interplay of local and global activities (Buzsáki, 2007).
Some modalities of oscillatory synchrony possibly requires the
participation of astrocytes (Fellin et al., 2004; Halassa et al.,
2007), developing into a late phase-locking of gamma, alpha e theta
frequencies (as proposed by Palva and Palva, 2007).
A chronology of events that include all relevant and compatible
findings would be the following:
a) Under 80 ms after stimulus onset, stimulus-evoked receptor field
responses occur in primary sensory areas, without conscious perception
of the stimulus;
b) Around 100-120 ms after stimulus onset pre-conscious priming
occurs. This is considered to be a phase that is necessary to trigger
the conscious process but does not generate the full conscious visual
state yet. The priming is done by a transient stimulus-evoked gamma
synchronization, encompassing primary sensory, higher sensory and
associative cortical areas, as described by Melloni et al. (2007);
c) Between 130-270 ms, a stimulus-evoked, feed-forward gamma
synchronous firing from sensory to associative areas occurs (see
single unit recordings, in visual areas of the anesthetized cat, by
Samonds and Bonds, 2005);
d) Around 270-300 ms, sparse responses to the visual stimulus occur in
higher associative areas (as registered by Quiroga et al., 2007),
which are related to the P3 component recorded by Del Cul et al.
(2007) and the P300 component referred by Melloni et al. (2007);
e) Beyond 300 ms, reentrant signaling from higher associative back to
sensory areas reach previously potentiated neuronal assemblies. From
this moment on, visual consciousness of the stimulus occurs. Gamma
oscillations, sustained with the participation of astrocytes in
glutamatergic tripartite synapses (Pereira and Furlan, 2007), become
phase-locked with alpha and theta (Palva and Palva, 2007), generating
brain-wide coherence of post-synaptic potentials.
As a conclusion, I recognize that brain correlates of visual
processing are more complex than previously thought. The picture that
emerges from the above synthesis of results is that correlates are not
reductible to a single event or type of event, but involve a complex
chain of distinct phases and mechanisms, as predicted in Arnold Trehub’s model of conscious visual
processing (Trehub, 1991).
References:
Buzsaki G (2007) The Structure of Consciousness. Nature 446 (7133):
267.
Fellin T, Pascual O, Gobbo S, Pozzan T, Haydon PG and Carmignoto G.
(2004) Neuronal Synchrony Mediated by Astrocytic Glutamate Through
Activation of Extrasynaptic NMDA Receptors. Neuron 43(5): 729-43.
Halassa MM, Fellin T, Takano H, Dong JH, Haydon PG. (2007) Synaptic
islands defined by the territory of a single astrocyte. J Neurosci.
27(24): 6473-7.
Quiroga RQ, Mukamel R, Isham EA, Malach R, Fried I. (2008) Human
single-neuron responses at the threshold of conscious
recognition. Proc Natl Acad Sci U S A 105(9):3599-604.
Melloni L, Molina C, Pena M, Torres D, Singer W, Rodriguez E. (2007)
Synchronization of neural activity across cortical areas correlates
with conscious perception. J Neurosci. 27(11):2858-65.
Palva S, Palva JM. (2007) New vistas for alpha-frequency band
oscillations. Trends Neurosci. 30(4): 150-8.
Pereira Jr A, Furlan FA (2007) Meta-Potentiation: Neuro-Astroglial
Interactions Supporting Perceptual Consciousness. Available from
Nature Precedings
Samonds, JM and Bonds, AB (2005) Gamma oscillation maintains stimulus
structure-dependent synchronization in cat visual cortex. J.
Neurophysiol. 93 (1): 223-36.
Trehub A (1991) The Cognitive Brain. Cambridge: The MIT Press.
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[Forwarded message from Bernard Baars]
Hi everybody,
Very good discussion on the time (and naturally spatial) aspects of
the “global broadcast” vs. “more local” ideas that are out there.
Alfredo makes the case for 100 ms vs. 300 ms, roughly corresponding to
Lamme’s position on “visual consciousness only needs visual cortex”
versus Del Cul & Dehaene’s position that “visual consciousness needs
frontoparietal activity.”This is demanding material, with tricky experimental issues that need
to be solved. It’s very much a live question right now.I think I would make the following claim—let me know if you agree:
1. when we do contrastive experiments, comparing conscious vs.
unconscious events (most often visual stimuli); i.e., using
binocular rivalry, Koch & Tsuchiya’s long-lasting rivalry; attentional
blink; visual masking (forward and backward); inatttentional
blindness; (Notice that Zeki’s work, and Macknik’s do not use
contrastive analysis, and are therefore not germane to this
discussion).2. and we look at slow spatially precise measures such as fMRI
3. given (1) and (2) the predominant result is frontoparietal
activation. See Rees, Koch, Dehaene and my own summary in TICS2002.
There are about two dozen studies showing this type of result under
different conditions.However, with fMRI we do not get good spatial resolution so far, or
rather our inferences are “referred backward in time” given the 5+
second rise time of the hemodynamic response that is reflected in
fMRI.For that reason, evoked electrical activity has been used, sometimes
combined with fMRI. It has good temporal resolution and somewhat
poorer spatial. Intracranial electrode grids have also been used,
which are in principle very precise spatially and temporally. And a
recent study from Tononi’s group used TMS stimulation during sleep,
and picked up wider spread during waking.The stereotypical event-related potential (ERP) is very responsive to
various cognitive tasks and stimulus properties. However, it has not
been easy to find a ERP correlate of consciousness – which surprises
me, since conscious vs. unconscious experimental phenomena are
extremely robust and plausible.One reason is that ERPs are always imposed on the cortical background
activity, like a ship going through the ocean. The ship creates its
own bow wave and turbulence, but the ‘spontaneous’ wave activity is
generally much greater. Walter Freeman and many others have emphasized
the extraordinary robustness of endogenous brain activity.Freeman is one of the few people who makes a very strong case for
understanding the endogenous activity. His papers on the “conscious
camera shutter” of approximately 50-100 ms are destined to become
classics, I believe, if they are not so yet. They take a little study.
Freeman’s latest meeting is on line with videos and ppts (click on the meeting folder on the left
column).A few major claims stand out right now about evoked potentials.
1. Revonsuo claims there is a Visual Awareness Negativity (VAN),
ranging from 100 ms to (I believe) 400 ms post-stimulus. Two studies
converge on that result.2. There is an older literature pointing to amplitude changes in the
P300, which disappears when people fall asleep and reappears in REM (a
conscious state). The connection with consciousness is disputed, I
believe, and P300 is sometimes said to be a “decision-related”
potential. But decision-making making depends upon the stimulus input,
of course.3. Del Cul and Dehaene have a backward masking paradigm, where you
subtract the effect of the mask from the effect of the target. If you
accept that, there is a beautiful little picture of a discrete
separation of the conscious ERP from the unconscious ERP at about 270
ms. So that implied Dehaene’s “ignition” of a frontoparietal network
around that time.4. Wolfgang Klimesch and his group look at Event-Related Synchrony/
Desynchrony, and I believe their latest claim is a consciousness-
related increment in alpha and/or gamma synchrony near 300 ms post-
stimulus. I have to double-check that.5. Thomas Ramsoy and I are exploring the hippocampal-neocortical theta
activity that is robustly associated with episodic memory encoding and
retrieval. The hippocampal complex has a relationship to neocortex
that is very reminiscent of a global workspace and its ‘unconscious
audience’ or ‘unconscious backstage contexts.’ Hippocampal-neocortical
resonance is believed to ‘contain’ the encoded conscious event as a
memory trace, and to trigger consolidation of that trace over time. So
this is one of the few areas where we can argue that something like
content-preserving broadcasting is taking place. Episodic memory is
memory for conscious events, of course, which are not ‘memorized’
deliberately, but rather are spontaneously encoded in memory merely by
paying attention to an event (i.e., making it conscious). So the
connection with conscious experiences is very strong.Since the classic patient HM, it has been believed that conscious
experience is not dependent upon the hippocampus itself. However, it
may be that visual consciousness converges on coherent object
representation in the inferior temporal lobe, adjacent to the medial
temporal lobe and hippocampus. If we assume that is true, we have one
version of a global workspace configuration in the brain.6. I am attracted to the idea that the cortex and thalamus allow for
multiple hubs (Llinas and others), and that phylogenetically deeper
structures have also played that role. (See Bjorn Merker’s articles).
So we are thinking of a hub-of-hubs model, in which one of a network
of hubs may be dominant at any given 100 ms. moment. Needless to say,
the conscious ‘moment,’ if there is one, is always part of a larger
set of unconscious processes, which Stan Franklin calls the ‘cognitive
cycle.’7. Just for clarification: I don’t have a strong sense that conscious
‘moments’ must be locked to the stimulus in a rigid fashion. It could
be that way, but I’m not sure. One possibility is that there is an
initial conscious ‘ignition’ (as Dehaene calls it) around 100-300 ms
post-stimulus, followed by a second wave involving the ‘meaning’ of
the stimulus, from 400-600 ms. As we know from the reaction time
literature, voluntary decision making based on a stimulus can be
delayed for seconds.I would be grateful for your comments.
Bernard
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Dear Bernard:
Your summary is very good.
Conclusions depend on finding strong temporal correlation of
stimulation, brain activity and reported consciousness. I intend to
re-study the different cognitive paradigms used in the experiments, to
decide which one allows better empirical determination of when the
conscious visual perception occurs. At first sight it seemed to me
that the Del Cul et al. paradigm was the most reliable. Without a
reliable temporal location of stimulus-locked visual consciousness it
is not possible to determine which is(are) the right brain
correlate(s)!
The Melloni et al. data (transient synchrony around 100-130 ms)
poses a difficulty.
I am trying to avoid ‘ad hoc’ explanations, but the only solution I could
find to integrate this result in the previous scheme is to postulate a
“pre-conscious” phase (i.e. a phase that prepares the conscious
visual state but does not generate it completely).
The problem is that the synchronized activity was found for visible
but not for visible words, while in the Del Cul et al. experiments the
(conscious) visibility occurred only 300 ms after the onset of the
stimulus when higher associative areas were activated (in cases when
the time interval between stimulus and mask allowed conscious perception
of the stimulus).
If we assume that in the Melloni et al. experiment subjects were already
conscious of the image of words at 80-130 ms, this result would be in
contradiction with Del Cul’s.
One solution is that the early synchronized activity may be necessary
to prepare (priming) the retinotopic system for the visibility of the stimulus,
but visual consciousness really occurs only when the primed system begins a stronger synchronized phase or when sensory areas
receives the reentrant signal from higher areas. This solution would
account for the facts that early syncronized activity does not occur for
invisible words, but alone it is not sufficient to generate visual consciousness.
Wilenius and Revonsuo, in their 2007 Psychophysiology paper, assume the
Lamme and Roelfisema (2000) and Lamme (2003) hypothesis that visual
consciousness requires feedforward and “recurrent” (feedback,
reentrant) signaling from associative to sensory areas.
They (W & R) got ERP recordings indicating that this process begins at
100 ms and ends around 300 ms. However, they seem to believe that for
some kinds of stimuli the whole process could occur in the time
interval of 100 ms.
My interpretation is that from 100 to 270 ms the process is mainly
feedforward and unconscious, and that the reentrant/multi-synchronous process with
consciousness of (any) visual stimulus occurs after 270 ms.
This paper is also valuable because they used several kinds of
stimuli, and checked their subjective effects, before analysing the
ERP data.Best Regards,
Alfredo Pereira Jr.
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[Forwarded message from Bernard Baars]
On the substance, I believe everybody (or almost) assumes that reentry
is a key part of the process. Lamme has a more specific claim about
reentry than others, and it will be rather hard to test, because in a
broad sense reentry is so endemic to the cortex. Almost all
connections are bidirectional, including the LGN-V1 connection. So the
microanatomy supports reentry routinely. That can be neuromodulated,
of course, so one can have different traffic flows through the street
map, but the basic map is reentrant at multiple levels.
Lamme also challenges the view (which I’m sympathetic with) that you
need something like global reentry as a condition of conscious
contents. In Dehaene’s view and that of other fMRI researchers, that’s
show by frontoparietal activation for conscious vs. unconscious sensory input, i.e., input that could in principle be analyzed in
posterior cortex exclusively. Since ERPs differences are typically
found in parietal and frontal locations as well as posteriorly, the
ERP literature seems consistent with that general view.
Your hypothesis is interesting, but I doubt whether there is a single
reentrant flow. I do like the general idea that there is a forward and
backward flow, involving of many “more local” reentrant cycles. That
hypothesis deserves to be articulated and debated all by itself. I
don’t have a strong commitment to the 100 ms vs. longer difference.
I’m still trying to get a stable sense of this large and somewhat
confusing literature.Bernard
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Thanks for the clarification about Lamme. It seems that he is referring to recurrent
processing within visual areas (occipital cortex). Let´s call it
“local reentrance”. If I am right in this interpretation, his proposal
is in the same category of S. Macnick’s (visual consciousness
depending on recurrent activation in visual cortex, including feedback
from V2,3,4… to V1).
Let’s call the Global Workspace Theory (GWT) requirement “global reentrance”. In my previous posts I
was (implictly) referring to global reentrance only. It is important
to make it explicit, since this is a feature that distinguishes GWT
from other approaches.
Besides determining which areas are involved, it is also
important to identify if the process is only feedforward, or forward-
backward, including global reentrance or not. Global reentrance is not
an ubiquitous aspect of cortical processing, but part of a global mechanism devoted to the formation of conscious states (i.e., a
specific NCC).
The many local reentrant cycles may compose a global
reentrance process. In this case, the local cycles are coordinated
with each other, i.e. they are not statistically independent. This
would be a central aspect of GWT.
The millisecond business turns out to be more fuzzy than I would
like, but I still claim that it is critical for our discussion. Those who defend that visual consciouness occur
100 ms after sensory stimulation are those who assume positions against GWT, while the defenders of 300 ms assume a GWT approach.
Therefore these 200 ms of difference make an important theoretical
difference.
The Revonsuo paper is also important because it is the only one (that I
know) that relativizes this time interval according to subjective reactions to stimuli. OK, this relativization makes things more
complicated, but we cannot ignore the subjective side of the problem.
The Del Cul et al. paper empirically correlates physical
stimulation, brain activity and subjective visual consciousness.
This is the reason why I am more inclined to trust in the 270 ms
interval.
BTW I did not explain before that the new technique of backward
masking (BM) introduced by Del Cul et al. seems to be directed to the task
of measuring the time needed for the subjective visual state to occur.
This technique is different from the attentional blink (AB), since in the
BM case it is the first stimulus that is masked, while in AB it is the
second. How it contributes to a more precise temporal location of the subjective report relatively to stimuli onset is a complex issue that I am still trying to understand better.Best Regards,
Alfredo
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Yes, all good points, Alfredo.
I’m quite cautious about assigning a specific time window to the conscious “moment” or “dwell time”, but not because I don’t think it exists. It’s just very hard to pin down in a foolproof way. So your proposal about the first 100 ms as being local or regional reentry vs. the 100-300+ period for global reentry (like Edelman/Tononi’s “dynamical core” and GWT “broadcasting”) is perfectly plausible. However, I don’t know if it’s the only way to go. It is at least conceivable that part of the conscious window may occur early on. Once we obtain a foolproof signal from ERPs or MEG/fMRI that correlates with conscious but not unconscious events, and which furthermore provides a plausible theoretical story for conscious but not unconscious functions, then we can take the next step, and say, Aha! It’s the Visual Awareness Negativity. (Like Antti Revonsuo and his coauthors). Or it’s P3b! (Like some ERP people). Or it’s global gamma synchrony interrupted by s a lot of very provocative evidence out there.
Bernard
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Dear Bernard:
I am in agreement with your analysis and expectations, while still worried about the physiological mechanisms that underlie each possibility. The “second wave” alternative (conscious experience of the stimulus occurring only during the second synchronized phase) would require a mechanism for the sustaining of post-synaptic potentials exclusive for conscious processing. If this is true, it opens a whole new area of research. The mechanisms for such a sustaining of post-synaptic activity would be different from those involved in sensitization, habituation, LTP, LTD and other kinds of cognitive activity that already have a scientific methodology to be experimentally studied. This could be one possibility for the development of consciousness science, attracting researchers from molecular neurobiology to our field!
Best
Alfredo
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Dear Alfredo, Dear Bernard,
the conscious moment is indeed a very interesting aspect of consciousness. In some respect consciousness only ever exists in that moment when whatever the content is, something becomes conscious. This is, regarding the properties, a feature that makes consciousness altogether different from thinking.
I agree it is difficult to pin it down, especially when it is attempted to be done via timing. The other path: via the content is also tricky, because content relies on introspection and reportability.
If we look at automatic driving, we would have difficulties to follow what at any given moment is conscious.
This does not only depend on different contents that may be more or less in the center of attenttion, but also on what could be called a state of mind, which maybe somewhere on a scale from being very much concentrated and wide open embracing many different lines of content, that may become conscious.
Another very interesting aspect of the conscious moment is that it is not repeatable. Thoughts are repeatable, in fact they can even be repetitive. Any conscious experience is a unique quale, that can never happen again in exactly the same way.Best
Hans -
Dear Hans:
One way to face this difficulty is to refer to “conscious episodes” instead of conscious states or conscious moments or “specious present” (James). The idea of an episode has a respectable history in memory research.
We are having advances in the scientific task of relating the space and time of conscious episodes with the space and time of physical stimulation and brain activity. Is there a limit for this progress? I do not see any ‘a priori’ reason to believe in an absolute limit for this research. We need more sophisticated methodologies to produce better correlations, and it seems that we are advancing in this direction!Best
Alfredo
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Dear Alfredo,
I agree, conscious episodes require memory. The moment/episode aspect of consciousness depicts possibly two different levels of consciousness that can exist together. To know that an episode ( = a series of conscious momentary experiences over a certain time ) has happened, requires either an analysis, an evaluation of the stored momentary experiences. Once episodes are known and longer periods of what has been experienced can be memorized, remembered and evaluated, we may forget how we actually learned to aquire this kind of knowledge.
There may be another option for an episode: it may be of help to introduce Christian von Ehrenfels and his view of a melody as a aGestalt., which is unfortunately an old German only publication – a melody then ( in the late 19th century ) has been gegarded as a good example for a Gestalt that is an entity that means more than its parts. A melody consists of notes and pauses, yet we recognize it ‘as such’ – as a Gestalt. This recognition is an act of consciousness. Moreover it does not require a mental act of recognition in a stricter cognitive sense: refering to thinking about it before realizing the Gestalt. It’s recognition appears to be, very similar to other conscious percepts to be immediate. Yet it requires a period of time, an episode.
It would be interesting to know what Sergio has to say about this aspect.
Yours friendly
Hans -
Stephen Rose’s work with chicks brought out the memory association with a sense of awareness rather than consciousness (awareness of being aware).
Thus there are snippets of awareness in ‘lower’ life forms where such are determined by stressful situations that require a shift in metabolism to ‘deal’ with the difference and then a settling down unless reinforced (and so conservation of energy overall – a feature of our instincts/habits creation and our habituation to sameness, over-sensitivity to difference)
The IDM focus on self-referencing and the chaos game brings out the need for DEPTH in the self-referencing and so, from a memory perspective we have to reach a certain level before categories turn into languages in that memories are strung together to move into the narrative and descriptive – and so from “AS IS” stimulus-response dynamics to “AS INTERPRETED” with our stimulus/considered-response dynamic.
If we focus on the language of EMOTIONS so we focus on emotional resonance that allows for sharing of symmetries through resonance. This realm precedes our consciousness realm and allows for amplification of such through consciousness.
Emotional resonance means a response to ANY sensory system harmonics, be it visual (colours) or auditory (chords) or the less developed in our species of gustatory, olfactory, or kinesthetic.
Results
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