Blindsight

Pam Blundell pjw106 at york.ac.uk
Tue Apr 4 09:11:17 EST 2000


"Marie" <toshrimpNOtoSPAM at hotmail.com.invalid> wrote in message
news:00f23a03.e9adb180 at usw-ex0102-015.remarq.com...
> Hi Pam,
>
> Thanks for your respons.  Yes, I realised that I did a mistake in
> my text with regard to neglect.  Due to neglect I guess!!! :)
>
> I have the Parking book, but what I don't seem to get to get a
> grip around is whether blindsight is a condition or a result of
> hemianopia.  SOmeitmes they are writing about blindsight as if
> that is a separate condition from hemianopia, but surely
> blindsight is a consequence of hemianopia!?
Hemianopia can be a result of damage to several different processing areas.
Blindsight will arise if the damage is in later processing areas.  If (for
example) the thalamus (LGN) is damaged, I don't think you would necc. get
blindsight, as this is before the separation of the visual pathways.
Similarly, you can get blindsight with complete blindness, not just
hemianopia, or with scotoma (small areas of blindness).

The two conditions, while they do sometimes co-occur, each one is neither
necc. or sufficient to cause the other.

Theres an interesting classic paper by goodale and milner (1992) in Trends
in Neurosciences that would be worth tracking down (its in the back of the
Ellis and Young book I cited in my last posting), that talks about the
differences between two pathways of visual processing, and is relevant to
this discussion.

Pam.







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