Jump to content


Senior Members
  • Posts

  • Joined

  • Last visited

About ashennell

  • Birthday 12/11/1978

Profile Information

  • Location
  • Interests
    guitar , photography
  • College Major/Degree
    Neuroscience & Biochemistry
  • Favorite Area of Science
    Computational neuroscience
  • Occupation
    PhD Student


  • Baryon

ashennell's Achievements


Baryon (4/13)



  1. Transfer of information to the cortex is certainly not just a feed-forward process, it does indeed dependant on modulation by information flowing back from the cortex to the thalamus. However, the idea that it acts as a filter in the way you describe is too simplistic to be meaningful. If anything, hallucinogens must relax the rules by which we interpret new input. We reduce the importance we place on sensory evidence for determining the state of our world.
  2. Neglecting half of your visual field is called hemispatial neglect. The individual often only has partial access to information from one side - they are not conscious of this area of space existing (but don't notice that it is missing) but in certain circumstances can use information that comes from the neglected area. It is most commonly caused by damage to the thalamus. Interestingly the neglect can have different frames of reference, so for example if you have three pictures arranged horizontally in a line, then only one half of each would be percieved. So , for example : -**- -**- -**- may be percieved as -* -* -* which, is pretty wierd.
  3. Was adam unable to do wrong? I wasn't aware of that. I assumed that he had free will and always chose to do good but my knowledge of the bible is pretty poor. Could we not say that the devil provided him with the opportunity to make a free choice by tempting him? If it is how you say, then this whole 'fallen in to sin' thing is even more ludacris than I had previously been led to believe.
  4. While im on this thread, I want to apoplogise to Matt for the comment I made earlier. It was very rude of me. I was just having one of those days where everything seemed to annoy me. Now that the fender thing has 'clicked' it is pretty obvious from the first post. I had never come across the 'ender' terminology and more importantly wouldnt of thought that grouping numbers by their final digit was significant or even useful. Perhaps this is why I couldnt get it initially.
  5. The proof (bearing in mind im not a mathematician at all) is something like: Any factors ending in 9, times 2, is a factor ending in 8, e.g. 19*2=38. 2 and 5 are both factors of 10 (and any number ending in 0). So any number with 9 and 0 as fenders, denoted a and b, can be rexpressed as a*2*(b/2)
  6. No, because as part of Q2 we need to show that any number that has 0,9 as fenders will also ahve four more. I one which is 8. So any number with 0 an 9 as fender must have 8 and hence the combination you require is impossible. Edit : sorry this is wrong, I will leave it here anyway. Edit : no it is correct after all. I need more coffee ....
  7. This seems akward to me. The hypothesis presented seems to be that evolution could be wrong if we found evidence that didnt agree with the theory. Is that a hypoethesis in it's own right or just part and parcel of what a theory is in general? Any theory could be shown to be incomplete given new evidence. However, is would be a mistake to imply that in disproving one theory you somehow have evidence to support another 'specific' one (I realise that woelen doesn't specifically go this far). If we find a new example of irreducible complexity, which somehow resists attempts to explain it, given evolutionary theory - why would this alone support any one other theory?
  8. Althought, I think the fenders you got are the right ones. i.e. 1,2,5,8,9,0 ...it took me a while to work that out. It isnt too hard to show that there are always these fenders. I'm not doing this problem sheet thing so I shouldnt provide answers.
  9. Some people who are blind still see patterns of colours in the visual field. Not caused by external stimuli but from nerual activity. So it is obviously not as clear cut as what you are suggesting. What do you you mean by 'learned a neuro response to black?'
  10. What you have to remember is that most neurons in the early visual cortex respond most vigourously to specific changes in intensity; lines, edges, corners and other features. So a matt black object in the visual field wouldnt produce much activity because a lack of contrast. But the same could be said for a solid green object or blue object. What neurons respond to are changes across their receptive fields. The short answer is that , if you are in a pitch black room then there is not a population of neurons coding 'this is black.' I expect that this is the situation in which there would be least activity in the visual cortex. Most black objects do reflect some light, highlights, etc that provide texture information or contours. People who are blind from birth do not see black, as has been pointed out, but this is not because their black coding neurons dont work. These people have not had the experience to learn an internal representation of visual space. Therefore they don't really have a 'canvas' to paint black. If you have had enough visual experience to develop your internal model of the visual world then you do need a way of representing no input.
  11. Colour is coded through 2 opponency channels - red-green and yellow-blue. Often, descriptions of the visual system include a third channel coding black-white information. But this channel is not really the same as colour information because black and white are not coded in opponency to each other. i.e., we can perceive intermediates (greys) between black and white. I doubt if the colour sensitive 'blob' regions of the cortex code this black/white distinction. It's late , I will try and give a clearer explanation when im not half asleep.
  12. He did reply to my initial question: Basically telling me to read something I'd already read and that dosn't actually contain a definition.
  13. Ok, so I worked it out. The last digit of the factor of a number is a fender for that number. Now the questions make sense. Obviously 'maths expert' dosn't imply 'helpful maths expert.'
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.