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The two papers cited above were used in a discussion of consciousness as an area of ongoing research in the Senior Seminar in Neural and Behavioral Sciences at Bryn Mawr and Haverford Colleges during spring semester, 1999. The following are comments on the article by participants in that seminar.


Name: erin hunter
Username: ehunter
Subject:
Date: Sun Apr 18 13:29:42 EDT 1999
Comments:
The anesthesia article by Kulli and Koch raised a number of interesting questions for me. I had never thought before that you could still be conscious while under anesthesia. But obviously, some people can be. After thinking about it, i realized that it actually made sense. If anesthesia works mainly on motor areas, then other brain areas could still be functioning, at least to some degree. Thus one could be completely consciuos yet unable to move. It made me think how torturous it would be to be in a coma and still be conscious. Yet how would anyone know that you were conscious, especially if changes in heart rate or blood pressure can't be reliably detected in conscious states such as pain and fear?

I think it is promising that there may be a measure for consciousness. if high-frequency oscillatory electrical activity can really be used as a measure of consciousness, then much more could be learned about consciousness. It is interesting that this electrical activity is looked at in both humans and cats. That would be inferring that cats are also conscious. If cats are conscious, what other animals are consious?

As for the article on hemianopic anosognosia, i admit i found it a little confusing. however, i admit that i may have just too tired to read it clearly enough to understand it. i thought that the question they raised about how we know taht we are missing information was a very interesting one. i just didn't understand how they answered it. i personally think that HAN could be explained by the way that we don't perceive our blind spots. Our brain is simply filling in the missing information enough that the person wouldn't really notice until the blind spot became so large taht that couldn't miss it.


Name: Erin Brown
Username: ebrown@brynmawr.edu
Subject: hemianopic anosognosia
Date: Sun Apr 18 13:40:48 EDT 1999
Comments:
This article made a number of interesting points. The attempt at localizing a spot in the brain needed for conscious awareness of brain functioning was carried out in a logical way. It is logical to look at infarcts for deficits in conscious processing of visual stimuli. I think that their comparison between amaurosis fugax and and hemianopic anosognosia, both visual deficits, could have helped extend their point on the difference between consciously perceived visual deficits and deficits that were not processed consciously. They were rather vague about what areas of the parietal and occipital lobes they were looking at when they concluded that there was no relation, but I think that their evidence involving lacunar infarcts and middle cerebral artery infarcts support their conclusion. I

I am particularly interested in their evidence that hemianopsia can be transient. If some of the patients experienced this only transiently, it would suggest that some sort of regulation was happening within the brain to bring unconscious events into conscious processing, a sort of re-wiring of the conscious circuitry. The study points to the cause of transiency as the doctor explaining the deficit and the patient understanding the explanation and accepting it. I think a more interesting interpretation of this is that the patient, once made conscious of the deficit, may be able to use conscious thought to regulate subconscious functioning or awareness. This would suggest that conscious functioning is able to regulate input and perhaps compensate for defects.


Name: Erin Brown
Username: ebrown@brynmawr.edu
Subject: anesthesia
Date: Sun Apr 18 13:52:27 EDT 1999
Comments:
I thought that Crick and Koch's correlation between conscious functioning and short term memory was interesting. Would it be possible to be conscious without short term memory? I am not referring to memory of five minutes or longer, but to immediate storage of sensory events. I don't think it would be possible as there would be no way to interpret unremembered sensory input. On the other had, since I do not necessarily believe that one needs input to be conscious, it is also interesting to look at how short term memory would be involved in intrinsic thought. If you could not remember what the first part of your thought is, it would be nearly impossible to continue formulating that thought. In this way, I think that their measurement of loss of consciousness based on lack of short term memory is accurate. It also makes me curious as to what sort of functioning would be possible in a brain lacking short term memory. Hmmmm.
Name: Noreen Khan
Username: nkhan@brynmawr.edu
Subject: anesthesia &hemianopic anosognosia
Date: Sun Apr 18 14:30:32 EDT 1999
Comments:

The article on hemianopic anosognosia was difficult to understand because I wasn't familiar with the medical terminology at all, but I think they had some very interesting conclusions. Basically they looked at people who had partially lost their vision and were not aware of it. Thus the researchers tried to locate possible regions responsible for conscious visual perception by examining which regions in the brain were disfunctional in these patients. Their results suggested that loss of visual consciousness could be attributed to lesions, or nerve loss, in various different regions of the brain and that "visual awareness requires integration of information distributed in relatively large cortical regions".

In the anesthesia article, the definition they use for unconsciousness is different from what I've been considering it to be. Their definition is specific for their purposes as anesthesiologists. They need physical measures of detecting whether a person is unconscious, so they measure autonomic responses, analgesia, amnesia, etc. However, I think there is more to consciousness that maybe they can't measure. For example, there is no way of measuring whether the person is thinking or not. They propose the 30-40 Hz method of detecting whether the person is unconscious. However, this method is based on observations that people who exhibit spontaneous movements or movements in response to a verbal command always show 30-40 Hz oscillations. Thus, it is only correlating motor responses to these oscillations, but we know that there is more to consciousness than motor response. I believe that a person who has lost all motor capabilities may still be conscious.

As we read more and more about consciousness, I am growing more convinced that there may be no way to measure and study consciousness. It may be impossible to objectively measure and study qualia, which by definition is a subjective "inner feeling".


Name: A. Forray
Username: aforray
Subject: Hemianopic anosognosia
Date: Sun Apr 18 21:19:07 EDT 1999
Comments:
The article on hemianopic anosognosia (HAN) proposed some very interesting ideas. Unfortunately I was not familiar with most of the medical terminology, which took away from my understanding of the article. Overall the article was clear in its purpose, although the results were not able to completely answer the questions it set out to explain. Despite this the authors did do a good job at explaining their results, especially what they meant and why they did not find what they were looking for. I found their idea that visual awareness is mediated through a "distributed network" was very logical and plausible. Their explanation of HAN as perceptual filling of the lost field was very interesting and made a lot of sense. If we normally fill in for our blind spot, why not do the same when we have loss of field? My only doubt about this perceptual filling explanation is why does it happen with only certain patients? Overall this article demonstrated to me, that the use of patients with visual field defects seems to be a good model for the study of visual consciousness, one which can contribute experimental data to the general understanding of consciousness (a problem we had faced in our past attempts at understanding consciousness).
Name: Luise Pernar
Username: lpernar@brynmawr.edu
Subject: Last Discussion
Date: Sun Apr 18 21:32:05 EDT 1999
Comments:
The writing on unconscious loss of vision was quite intersting. Maybe I did nto understand it right, but how did the scientists determine patients had loss of vision if even the patients were not aware of it? I laregly agree with Erin Hunter that the findings, i.e. that the patients did not realize they had vision loss, are not surprising because the brain fills in gaps in our visual field at all times anyways.

The articel Does Anethesia Cause Loss of Consciousness addressed a point Professor Grobsteion brought up the last time we met, namely, can you know that somebody is conscious if they are incapable of movement? Professor Grobstein argued that one could not know a person was conscious unless tat person could give a sign of his or her consciousness. This is the same problem doctors seem to face when putting people on anethesia for an operation. I was astonished to read that consciousness could be inferred from auditory evoked responses. This way of measuring consciousness seems a bit too simple alomst. Afterall, auditory evoked reponses indicate only that an auditory stimulus has been received, it should not reveal that consciousness is present. That the author cited evidence from cats surprised me as much as Erin Hunter. As long as it is not established that animals are conscious, even though I do not doubt this, evidence derived from measuring their outputs should not be used to 'prove' consciousness is present. Generally, I believe the article was very telling about the state of consciousness research. We simply do not know what consciousness is and what we must be lookig for in order to find out. I agree with Noreen Khan when she says she doubts we will understand consciousness soon - the evidnece we have encountered till now is not convincing.


Name: Bindu Krishna
Username: hkrishna@brynmawr.edu
Subject: anesthesia and hemianopic anosognosia
Date: Mon Apr 19 15:36:06 EDT 1999
Comments:
The Kulli and Koch article brought up a few interesting points. First, their evaluation of consciousness was different from what I had been thinking. Since they were examining consciousness in patients under anesthesia, I understand why they isolated organized movement and recall to identify whether or not consciousness was present. The idea that patients are aware/conscious to some extent during surgery was disturbing at first (particularly because my dad is an anesthesiologist), but then I rationalized that many procedures are currently done with the patient being awake, but insensitive to pain (local anesthesia). Another interesting point that came from this article was the oscillatory electrical activity measures. Throughout this semester there have been many aspects of consciousness discussed, but very few can be accurately measured. Since this high-frequency activity may be an actual measurement tool, it takes us away from the abstract discussions into something more concrete.

The second article, on hemianopic anosognosia, was very difficult to understand. At first I was confused over the medical terminology, but after reading it through twice, I understood it better (not well...just better). The idea of the experiment was extremely interesting to me. The idea that one could just not be aware of a body defect is definitely something to look into. A good method for approaching this discussion is the exmination of the deficit of the visual field. From what I understood, they were trying to locate areas in the brain to identify as causes for the unawareness of the deficit. Also agreeing with Erin Hunter, I think HAN could be explained swomewhat by the fact that our brains normally compensate for gaps/blindspots in our visual fields. However, this article did make a step into examining the idea of visual consciousness, or consciousness derived from visual stimuli, which I think is a good area to look into.


Name: Jennifer McCallum
Username: jmccallu@brynmawr.edu
Subject:
Date: Mon Apr 19 16:08:36 EDT 1999
Comments:
Re: Kulli and Koch

This article has proven how badly we need to determine what is consciousness is and how to define it (or what unconsciousness is and how to define it). It is obvious from the reports of patients after being anesthetized that loss of consciousness is not defined by a loss of movement, nor a lack of response to a strong stimulus. The second criterion has bothered me for some time. The reason it has disturbed me is because the ability of strong stimuli (such as running a serrated wheel over, or pinching of the skin) to elicit a response is also used as a measure of consciousness in patients who may be comatose or otherwise brain injured or unresponsive. I often wondered whether the patient actually feels the stimulus but is in a locked in state. As horrifying as it may be to be presumed unconscious while actually being aware, imagine being in that condition for a year as a result of an injury. I havenít heard of such reports, but the thought none the less is a scary one.

In any case, another criterion for determining lack of consciousness that is interesting yet not quite as disturbing is the lack of recall. I wonder how lack of recall can be used to say someone was unconscious. Perhaps the person was conscious but does not remember being so. Sound silly? Perhaps, but when I canít recall for the life of me what happened three days ago at breakfast, does that mean I wasnít conscious? Or, what about people who block out, and are therefore unable to recall, horrifying and/or traumatic past experiences? There is no recall here. Does this mean the person was not conscious or aware? There is a pharmacological explanation for how benzodiazepines block recall, but this is still interesting to think about. Especially if one is tempted to use recall to determine awareness/consciousness in an unanesthesized person. Further, if someoneís short-term memory system is damaged, is that person unaware and unconscious, even though they are living each moment for the moment? I believe there is a documented story of just such a case, I donít however remember this person being referred to as unaware, unconscious, or unable to experience. Perhaps Alzheimerís disease provides another example.


Name: Kelly
Username: kmack@brynmawr.edu
Subject:
Date: Mon Apr 19 16:55:19 EDT 1999
Comments:
Both this week's articles present some interesting concepts and questions to the matter of consciousness. Starting with the article on blindsight (or various versions of sight problems), I think that looking at this phenomena is particularly useful because we have done so much reading on the visual system. Additonally, this is the first argument that I have read which suggests that we decompartmentalize our conception of the visual system and see it as more of a broader system present in multiple parts of the brain. The research that I have learned about in the past suggested increasingly differentiated areas were certain systems are located. This occurs in research not only concerning the visual system but also such things like motor function and hearing. If we are moving towards a more global picture of the brain, where functions are spread across interacting areas more like the nodal network models, then consciousness would also be more likely to be a global or whole brain function than as a mansifestation of a particular part of the brain.

The article on anesthesia and consciousness is also a fascinating work because it is an attempt at understanding what brain functions or measurable activities could be recognized to represent consciousness. The idea of anesthesia in itself is interesting and how the combinations of certain drugs produce different kinds of anesthestetic, such as anterograde amnesia but the ability to have interactions with patients while in surgery. We might ask if the person is conscious at all if afterward they do not remember what happened. Would this be one of the zombie states that we discussed previously?

I am interested in seeing what other kinds of measurements might be able to develop in order to detect consciousness and therefore make anesthesia a more effective tool during surgery. However, I think this is a very difficult process because there are so many measurements of activity that we can read from the brain while not knowing what, if any, significance they have as well as whether this is a measurement of consciousness or other types of activity in the brain.


Name: Neha Navsaria
Username: nnavsari
Subject: last discussion
Date: Mon Apr 19 18:24:14 EDT 1999
Comments:
I think that the last two articles for this weeks discussion were very interesting to read. However, the article on Hemianopic Anosognosia was somewhat confusing. It makes sense for individuals to lose their vision in either their left or right visual field and not realize it. I remember in Intro psych we discussed the structure of the visual cortex and the occipital lobe and how it was attached to the optic nerve. I found it interesting to see many investigators propose the parietal cortex as another area besides the visual cortex that are related to these visual problems, thus making the system more complex.

I found article by Kulli and Kock to be very interesting because it addressed the question that has been brought many times during our discussion. It seems that the definition that an anesthesologist uses as being unconscious is based on the aspect of movement. I found the idea of recall to be very interesting too. I wondered whether the patients who were quoted in the beginning of the article were actually did have consciousness during the procedure or they just had distorted memories due to the anesthetic which made them think that they woke up during the procedure. It seemed that this article focused a lot on movement and unconsciousness. If you think about the people who woke up during the surgeries, they were conscious of the operation, but they couldn't move or say anything about it. I think that doctors need to rework their definitions of unconsciousness during operations and incoporate the work on neuronal oscillations and STM into this problem. It was interesting to read about the patients who were read a list of words and recalled them after recovery. This helps support a theory of cognition that states that priming doesn't take place at the memory level, but at the perceptual level because amnesics show the same behavior by not remembering they saw the words, but recalling them when they were presented with a task.

The theme of "all or none" was also shown if both of these papers for consciousness. Both papers asserted that you cannot either conscious or unconscious. Kulli and Kock stated that the recall of an anesthesized patient is usually incomplete or distorted, but it is not all or none. Critchley in the other paper asserted that hemianopic anosognosias varied along a spectrum of total absence of awareness to relative degrees of awareness for their deficits. I found this to be an interesting theme related to conscious that should be considered when trying to define or describe consciousness.


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