1 00:00:05,049 --> 00:00:09,600 << opening instrumental music >> 2 00:00:09,599 --> 00:00:14,250 [Narrator] Unlike Graham, Peggy Palmer has normal vision. 3 00:00:14,250 --> 00:00:17,500 She should be able to copy this star easily. 4 00:00:17,500 --> 00:00:19,899 [Peggy] "I'll never get this star I'm hopeless at this." 5 00:00:19,899 --> 00:00:22,989 [Narrator] But something odd is happening. 6 00:00:22,989 --> 00:00:27,549 One whole side of the star is missing. 7 00:00:27,550 --> 00:00:31,440 Peggy has a condition called visual neglect. 8 00:00:31,440 --> 00:00:33,909 Although her eyesight is fine, 9 00:00:33,909 --> 00:00:39,049 half of her visual world no longer seems to matter. 10 00:00:39,049 --> 00:00:44,219 Ten years ago, Peggy suffered a stroke in the parietal lobes of her brain. 11 00:00:44,219 --> 00:00:48,319 [V.S. Ramachandran] "The parietal lobes are concerned mainly 12 00:00:48,319 --> 00:00:50,599 with creating a three-dimensional representation 13 00:00:50,600 --> 00:00:55,419 of the spatial layout of the world allowing a person to walk around 14 00:00:55,419 --> 00:01:00,709 to navigate, to avoid bumping into things. 15 00:01:00,709 --> 00:01:02,660 When the right side is damaged 16 00:01:02,660 --> 00:01:07,740 the patient is unable to deal with the left side of the world. 17 00:01:07,739 --> 00:01:11,640 [Narrator] This condition has fascinated neurologists for more than a century 18 00:01:11,640 --> 00:01:17,278 because it reveals not only how the brain shapes the way we perceive space in the present 19 00:01:17,278 --> 00:01:22,300 it even determines the spatial look our memories. 20 00:01:22,300 --> 00:01:27,608 This became apparent when Peggy was asked to draw a daisy from memory. 21 00:01:28,479 --> 00:01:32,619 "Alright, a daisy it shall be" 22 00:01:32,619 --> 00:01:39,118 [Narrator] For neuropsychologist Peter Halligan Peggy's drawings reveal exactly what's gone wrong. 23 00:01:39,118 --> 00:01:42,108 [Peter] It is like a radar system whereby 24 00:01:42,108 --> 00:01:47,179 the actual radar system on the left hand side is no longer working well. 25 00:01:48,519 --> 00:01:50,739 If someone comes into my left hand side now 26 00:01:50,739 --> 00:01:54,619 or I hear a sound my eyes will immediately move to left hand side 27 00:01:54,619 --> 00:01:58,219 that makes me, for evolutionary purposes very aware of my environment 28 00:01:58,218 --> 00:02:01,339 because I wasn't aware of those things I would have accidents 29 00:02:01,340 --> 00:02:06,030 I'd get hurt or I might get eaten by wild animals and whatever. 30 00:02:06,030 --> 00:02:09,169 Now, in Peggy's case she will not attend to those things 31 00:02:09,169 --> 00:02:13,400 that we would normally be aware of. 32 00:02:13,400 --> 00:02:16,160 [Narrator] Peggy thinks she's drawn her daisies right 33 00:02:16,160 --> 00:02:19,619 until it's pointed out to her. 34 00:02:19,619 --> 00:02:20,990 [Peter] "You've noticed that, have you?" 35 00:02:20,990 --> 00:02:22,790 [Peggy ]"Oh, dear." 36 00:02:22,790 --> 00:02:26,310 [Peter] "So what Peggy's drawn for us is several nice daisies 37 00:02:26,310 --> 00:02:30,110 with the left side missing same this one and this one 38 00:02:30,110 --> 00:02:33,359 look at this one this is a very good example" 39 00:02:33,359 --> 00:02:36,019 [Peggy] "I've done it on all of them" 40 00:02:37,430 --> 00:02:41,960 [V.S. Ramachandran] Which means she's not only neglecting events in the world but when she 41 00:02:41,960 --> 00:02:47,150 conjures up a mental image she's ignoring the left side of that mental image. 42 00:02:47,169 --> 00:02:49,349 [Peggy] "I thought I was going all the way around you see" 43 00:02:49,349 --> 00:02:53,289 [MD] "And the shows you that this is not simply a sensory problem but 44 00:02:53,289 --> 00:02:56,439 a problem of consciousness" 45 00:02:56,439 --> 00:03:02,210 [Peggy] "It's cause I was so concentrated on that side takes everything away, you see 46 00:03:02,210 --> 00:03:07,269 It is attention really is taking this taken away this 47 00:03:07,269 --> 00:03:13,209 there must be two attentions somewhere in your body one side's taking another one away. 48 00:03:13,209 --> 00:03:15,939 I can't make it out at all, very odd" 49 00:03:15,939 --> 00:03:18,277 << closing instrumental music >>