Visual Processing - Science topic

Yes, it is doable using 2ries that less overlaping as suggested. But be aware that fixative can quench GFP but if its the eGGP shouldnt be a problem. And remember to do all of staining process away from the light not only after 2ry incubation not to lose GFP signal. Good luck!

Much chemical process modelling and/or simulation work can be done with the widely-used Microsoft’s Excel.

Application example ― Simulations carried in Excel 5.0 with Visual Basic for Applications (VBA) macros ― The recursive least squares algorithm (RLS) allows for (real-time) dynamical application of least squares regression to time series. Years ago, while investigating adaptive control and energetic optimization of aerobic fermenters, I have applied the RLS algorithm with forgetting factor (RLS-FF) to estimate the parameters from the KLa correlation, used to predict the O2 gas-liquid mass-transfer, while giving increased weight to most recent data. Estimates were improved by imposing sinusoidal disturbance to air flow and agitation speed (manipulated variables). The power dissipated by agitation was accessed by a torque meter. The proposed (adaptive) control algorithm compared favourably with PID. This investigation was reported at (MSc Thesis):

The module 'spectral' can do that. Have a look at http://www.spectralpython.net/

Hi Mostafa Y Nassar

I am working on the adsorption of various gas molecules on Cu-doped MoS2 system.. I am asked to calculate the threshold value of charge transfer for the adsorption to occur.

I am using VASP 5.2 for the calculations. I calculated charge transfer using Bader charge analysis and used the software VESTA for charge density difference plot.

Hi Ryan

Take a look at Gauthier T, Tarr MJ Becoming a Greeble Expert etc..., Vision Research 1997, 37, pp 1673-1681.

It may help.

Regards

Michael

Sear professor, Thanking you so much for providing us your response. Although, my question on characterization is relating to artificial intelligence view of the exogenous vision. Yet, your response enlightened me and I am sure it will help other interested researchers in this area of work. Thanking you so much, Homayoun 

Hi, good question, I think that Creativity in a way is rule based. In Play there is the idea of Padia, which is open play, but research has found that in open play, those in the experience impose rules themselves to make it more interesting for themselves. So I think that open creativity is impossible, as people impose rules as they work though the creative endeavours, if this makes any sense. 

It appears it is suggesting If shown visuospatial data and then a short time later is shown additional such information, the person may struggle to distinguish between them or use the material in a useful manner to think through a problem.  As Ryan said, the computer-generated interpretation seems nebulous. 

Thanks everybody,

your suggestions are really helpful. For now I have successfully increased the data acquisition precision by bypassing analysis and using serial port terminal apps such as puTTy and CoolTerm to capture data and analyze it later.

:)

Best,

Jan

Dear Antonio Lucero

You righty say that teachers and educators often refer to old works by philosophers, psychologists, and social scientists to support their theories and practices in education. But, almost never -- you say -- have you seen references to the modern science of the brain regarding how we humans learn. In your wise considerations, you also refer to "a valid model of how the brain learns."  Let me say that when you advise us to look at "how the brain learns", you are assuming, if I am not wrong, that it is one's brain that learns. Of course, we need our brain to learn, to see, and even to walk. But, if we performed a conceptual or grammatical investigation a la Wittgenstein, would it not be abusive and even misleading to say that it is our brain than learns, sees, and walks? 

To my understanding, it is learners or people as a whole and immersed in a given physical and social milieu or in a certain language-game, as Wittgenstein used to say, not their brains, who learn. Of course, when we learn, several things happen in our brains, for example, in terms of electric potentials, neural firings, connections among neurons, and the like. Without any doubt, it is important to know what happens in our brains when, for example, we passively learn by rote learning or by actively reconstructing or reinventing what we learn, as Piaget used to say. More than anyone, neuroscientists are in good position to do this important job and they are actually doing it. 

Note also that important and widely acclaimed teachers, such as M. Montessori, C. Freinet, and P.Freire, were excellent teachers, and yet they knew little, if any, about one's brain functioning. I guess that many present-day excellent teachers know almost nothing of the brain's functioning. Of course, I also admit that they could be more excellent teachers than they are if they took into account neural findings, namely those related to teaching/learning.

I know that neurosciences are now much in vogue. Thanks to them, our knowledge of the brain is now much more advanced than it was in the past. It is wonderful that we can profit from such knowledge to ameliorate the way teachers teach and students learn. Even though, I think that it makes little, if any, sense to say, as many neuroscientists do (e.g., Damasio, Gazzaniga) that our brain is social, moral, ethical, pedagogical, and the like. It makes good sense to say of a person that s/he thinks or acts in a social/antisocial, moral/immoral, ethical/unethical way. It is misleading and even nonsensical, however, to say, as neuroscientists tend  to do, that our brain is social/antisocial, moral/immoral, ethical/unethical, and the like.This means that I do not follow neuroscientists when they attribute to the brain, say, predicates that are applicable to a person as a whole (e.g., moral or immoral,  knowledgeable or relatively ignorant). As teachers, scientists, and  so forth, we should always look critically at all breakthroughs whatever.

Best wishes, Orlando

Benjamin Walter (1935) The Work of Art in the age of Mechanical Reproduction. and Arthur Danto (1974) The Transfiguration of the Commonplace. 

Hi Serge,

1. What kind of stimulation protocol are you using? it is possible that you are activating a very large neural population and the monkey ""see"" a big phosphene not clearly spatially localized. 

2. Are you sure the electrode is not moving? Are you compering the RF measured at the beginning and at the end of the stimulation?

3. Are you sure the monkey understood the task? I guess a phosphene can be a very strange stimulus for a monkey. It could just try to make a saccade away from it.

good luck

With my pleasure.

A related control issue is sleep quantity, quality and circadian timing preceding the experiment.  We instructed subjects to sleep eight hours per night for the three nights preceding an experimental session, retiring and arising at the same times of night/day.  Also, we always tested at the same time(s) of day/night.

John Wattam-Bell told me once that newborns (< 1 month old) can sometimes exhibit greater corneal reflectance, which can degrade the eye-tracking signal.

To be honest though, I wasn't aware that eye-tracking *cannot* be used with newborns, and I am somewhat sceptical of that claim. That said, since neonates are seldom awake, and have extremely low acuity I can well-imagine that it would be extremely difficult to conduct an eye-tracking experiment in such a population (e.g., like you say motivating them to complete the calibration procedure alone would be very taxing..), and more passive techniques, such as ERPs, are generally preferable.

EDIT: NB: I don't think your 3 reasons are the primary ones, since they would not be unique to automated/infrared eye-tracking (and manual/human gaze-tracking in neonates is certainly feasible!)

For overt shifts of attention (ie saccades), and distractor effects there is a spatial structure. These have been described geometrically (ie mapped). See  Walker et al (1997)  J Neurophysiol 78:1108-1119 and cites. Not sure about covert shifts of attention. 

I'm not sure how directly relevant, but this is a useful read for anyone thinking of using EEG: Michel CM, Murray MM (2012) Towards the utilization of EEG as a brain

imaging tool. NeuroImage doi:10.1016/j.neuroimage.2011.12.039. https://www.ncbi.nlm.nih.gov/pubmed/22227136

In an embodied cognition perspective, it can also be explained by the fact that all our sensorimotor interactions take place in a 3D space. As a child, we learn about our environment through the coupling between our actions and their sensory consequences. It can be assumed that our higher level cognition (i.e., thinking and imagining) is grounded in these low level sensorimotor contingencies.

In the same line, the following paper proposes that "The emergence of spatial notions does not necessitate the existence of real physical space, but only requires the presence of sensorimotor invariants called 'compensable' sensory changes.". These compensable sensory changes correspond to the changes in our perception that we can compensate by some bodily actions. According to the authors, this could be the key to understanding the notion of space.

That sounds too simplistic, even a bit anthropocentric. As primates we are more visual than other mammals and species of other classes. (Eagles, of course, are a notable exception to this.) Other sorts of potentially relevant stimuli for predators that come to mind are movement (in frog vision) and smell (in many species). I think you would have to consider the perceptual and cognitive systems of each species of predator to really get a handle on this, as these systems are inextricably bound to corporal morphology.

There are studies that indicate that (visually perceived) shape is one factor (among others) in predator recognition by primate prey (another kind of "flip side"). Derek Hodgson has written about the recognition of felids by hominins; check out his ResearchGate profile for publications. There is a growing body of literature on snake recognition by human and nonhuman primates. Our primate ancestors used to be a major food source for constrictors, and venomous serpents continue to cause a lot of human deaths. Some of the researchers who have looked at this are Richard Coss, Judy DeLoache, Hogshen He, Lynne Isbell, Nobuyuki Kawai, Vanessa LoBue, Arne Öhman, Michael Penkunas, and Brandon Wheeler.

Hi

When looking at process piping vibration, the rule of thumb is that the human eye exaggerates vibration by about a factor of 10x.

This is easy to verify, just put a marker on the vibrating object and a ruler next to the marker. I have arrived at a similar factor using also other more serious equipment such as position lasers, LVDT, YoYo pots and accelerometers.

The best explanation I have been able to come up with is that the human eye tracks motion up to about 4 Hz and in doing so, that the eye is rolling in the eye socket. This implies that scale matters, i.e. video tape and playback on a 15 inch screen and things no longer look as impressive.

It will be interesting to hear what the RG community has to say on this matter.

All the best

Claes

Thank you all for your answers and I do share your point of view. I'll look into the presentations

Regarding the link for hubel's book:  http://hubel.med.harvard.edu/

I also think that stimulation's lack of focality may be delivering contradictory information to the brain hindering perception. For example, you may be simultaneously activating a combination of neurons that the brain does not expect to be activated together..

It needs deeper thinking..I'll try again considering your answers 

Something to focus on:

Regards,

Joachim

I suspect it improves their interest in the task, which increases their attention to the stimuli, rather than it reinforcing their discrimination per se. It may be that the timing of those features could be where it detracts, but otherwise increasing attention will probably just be a good thing.

Hope this helps!

Visual impressions are converted into and stored as

tuples of symbols. Imagine the view of a cluttered

desktop: from a glance you can only keep a

working memory -ful of items. I'd like to

mention Kim's Game.

Visual working memory is restricted in capacity

to the Miller constant. On the other hand, we

don't have one working memory for auditory

and one for visual items: we only have a single

working memory for items of any modality, in

a neutral currency, the symbols.

Packets stored in long term memory can only

be recalled in a reliable way if any packet fits

entirely into working memory. Bigger data

structures can be made by linking pairs

of tuples by containing the same symbol,

like the equi-join in relational databases.

Literature

Regards,

Joachim

Simon, you're absolutely right to be critical and to question existing research paradigms. The problem with any new paradigm is that, at first, it may give a sense of deeper insight, but later, starts to wear off until it indeed may impede further progress. Yet, in the absence of a better paradigm, one often keeps on working with it. This is troublesome especially if its paradigmatic ideas are mistaken for the “truth” (whatever that may be). By the way, as I argued in my CogProc paper, I do not think that the cognitivist/computationalist paradigm has worn off, but I do think that it needs to connect to complementary concepts and ideas from, e.g., connectionism, dynamic systems theory, and neuroscience.

You're also absolutely right that the terminology in any paradigm carries a lot of questionable ontological bagage. This is nagging but I think also inevitable in our continuing quest for appropriate analogies, methaphors, and models by which we can only approximate the “real thing” (whatever that may be). In this sense, I am open to what is called a metaphysical (or ontological) reading of pluralism (which assumes that a "grand unifying theory" is possible), but for the moment, I adopt an explanatory (or epistemological) reading of pluralism – which, more pragmatically and in the spirit of David Marr, focuses on differences and parallels between existing explanations at different levels of description to see if and how they might be combined. My hope is that, eventually, this will lead to new and better thinking structures.

– Peter

Hi Analisa,

yes, as Vittorio Porciatti wrote, there is a reliable way to do that. It's the Westheimer paradigm (no "r" in Westheimer), and the field size that is measured by it is called the "perceptive field size".Oehler (1985) has even used it with monkeys, and the seminal paper is by Lothar Spillmann. There is a chapter in my review on peripheral vision on it:

(or go to my website, ww.hans.strasburger.de)

 I would start with Libet, Benjamin; Gleason, Curtis A.; Wright, Elwood W.; Pearl, Dennis K. (1983). "Time of Conscious Intention to Act in Relation to Onset of Cerebral Activity (Readiness-Potential) - The Unconscious Initiation of a Freely Voluntary Act". Brain 106: 623–642. doi:10.1093/brain/106.3.623. PMID 6640273.

The paper does not answer your question  concerning color directly, but I would look up him on Google  for other references as well . If you find no "Libbett" experiments using color, then you have to do it yourself. In fact designing the right experiment should be straightforward.Let me know.. I may have some suggestions. In particular , you may be explore the effects of categorical versus complimentary color stimuli .

One way to approach your question may  be to look at opponent ganglion cells responses (with their species specific photoreceptor inputs).  For an overview of color vision in animals I would refer you to Dr Gerald (Jerry) Jacobs book: Comparative Color Vision (1981).  He has a long career studying color vision (and pigments) in a variety of species

Here are just a few papers:

Neitz, M., Neitz, J. and G. H. Jacobs (1991) Spectral tuning of pigments underlying red-green color vision. Science, 252, 971-974.

Jacobs, G. H. (1996) Primate photopigments and primate color vision. Proceedings of the National Academy of Science USA, 93, 577-581.

Jacobs, G. H. and J. Nathans (2009) The evolution of primate color vision. Scientific American, 300 ( #4), 56-63.

Jacobs, G. H. (2009) Evolution of colour vision in mammals. Philosophical Transactions of the Royal Society B, 364, 2957-2967.

Another organism modeled well with complementary colors is the honeybee:

Backhaus W, Menzel R Color distance derived from a receptor model of color vision in the honeybee Biological Cybernetics , 55, 321-331, 1987

Hi Stefano,

in order to have a survey of theories on image or, in narrower sense, picture perception you might see Hecht, Schwartz et Al (2003), Looking into Pictures. An Interdisciplinary Approach to Pictorial Space. It is interesting also Cutting & Massironi (1998). Pictures and their special status in perceptual and cognitive inquiry. In J. Hochberg (Ed) Perception and cognition at century’s end. New York: Academic Press, (pp. 137-168). In general in this field, like many others, there can be distinguished an inferentialist-constructivist approach from a direct or a "directed" perception approach. Another difference cutting across this distinction is that between those who take images as something similar to marks and signs and those that do not. In the first case you can have a look at Ittelson (1996), Visual Perception of Markings, Psychonomic Bulletin. In the second case, there is the experimental and theoretical tradition of phenomenology intended in the Berlin-Graz and Italian School sense, i.e. Massironi himself, Bozzi, Vicario and many others. I myself have tried to derive a theoretical model of which cognitive capacities could support picture perception and how this one could help in assessing the neurobiological models. I understand that many more issues could be at stake depending on the particular topic you are addressing to. Hope it will help

Bear in mind that covert shifts of attention can happen in the absence of eye movements (which is why they're called covert).  See for example the introduction of the article linked below.

I would say navigation, either on urban or non-urban environments, that can add some changes to the daily activity that routes us from house to work/school to shopping: walking, cycling, driving or sailing, out of / expanding the daily routine surrounding environment. And perhaps also using external imagery like maps in paper or smart devices with LBS (Location Based Services) and possibly AR (Augmented Reality), that can reference or inform the place and the corresponding bodily experience, spatial cognition and the mental imagery of the surrounding environment. If all this can be reproduced in a complete VR (Virtual Reality) environment, is an issue that is being study by Neurosciences and Design, and maybe there is not a definite answer ... 

An interesting, free-ranging conversation. As a meditation teacher, I'm exclusively interested in dissolving and eliminating all stress, anxiety, and other negative effects that limit a person's functioning in life, that limit or prevent their natural experience of peace. love, and happiness. Nevertheless, I see the value of academic reasoning and research into all the topics that we are all raising here. While I recognize the value of research, I remain focused on directly helping people live better by eliminating their stored stresses so the nervous system can function fully and properly.

Thank you Markus Huff and B.L. William Wong for the reply. They are really helpful,  i am happy that they are helping me out to see things with different perspective. Thanks a lot.

Hello Sarina,

You have been well served with theory, so i thought that I would take a more pragmatic, nuts and bolts approach to what I think is your problem. Am I right in thinking that you want to present visual stimuli to observers, record their spontaneous eye movements and fixations on these stimuli, and then, by analysing the distribution of eye-fixations, fixation times and perhaps scan paths, find evidence for or against what you call “grouping”? Let’s leave what we mean by “grouping” for the moment. When you have recorded the x-y coordinates of your observers’ fixations on your stimuli, their fixation durations, it is possible to look at the distribution of fixations and duration as a three-dimensional map for just one observer or cumulatively across all your observers. You can do this easily using a three-dimensional chart in Microsoft Excel, and see in detail where any observer has “grouped” his or her fixations and fixation duration on any one visual stimulus. You can also look at the accumulation of fixations and fixation times across one or many observers and/or across one or many stimuli.

Some may argue that this method of judging where “grouping” of fixations and duration on the stimuli has occurred is just a bit too subjective. Some people may see groupings in the distributions that others do not. One step towards a more objective analysis of the distributions is to use cluster analysis. There are at least a couple of cluster analyses that can be used with eye-movement data - k-means and the Wallace-Boulton Information measure. I have attached a paper explaining how to carry out the analyses described above. There are other papers on the use of cluster analysis on eye-movement data, but until we are sure that this approach is going to be useful to you, we can leave these and also treatment of scan paths aside.

There are also two ways to approach your problem. You could begin with a theory that predicts where “grouping” will occur. For example, if your stimuli were alphabetic characters, you may predict that attention would be concentrated (grouped) around the most discriminating features of the characters. You may have reason to believe that some parts of your visual stimuli are more “salient” than other parts, and will attract more attention. The described data-analysis methods can help you test these theories. A second approach is simply to have no theory and look at where attention is grouped on your stimuli, and on the basis of your results, work towards some predictive theory that could be tested on new stimuli. Note too that the distribution of attention is going to be strongly influenced by the task demands, the nature of the stimuli and instructions to the observers.

It will not have escaped your notice that I have moved from talking about eye movements and fixations to “attention” - a controversial move that could be discussed. I have also introduced the term “salience” - a real can of worms that one! And, while I understand the Gestaltist notion of grouping, I am a little unsure of what you and the other commentators mean by the same term.

One simple answer would be that our brains have evolved from back to front, so the back of the brain where we process visual information is very old (evolutionarily speaking) while front (where we think) is much newer. Thus animals were able to see long before they evolved to pose questions about brain organization.

Tiago, the MARMI and the MASMI are in Research Gate. I am sending you the MASMI and a article. If you need more information, please tell me it.

Bye