cognitive fun! talk RSS http://cognitivefun.net Cognitive neuroscience for everyone! Sat, 25 May 2013 04:28:55 +0000 This is excerpted from the introduction of the paper that medicalstudent linked: London taxi drivers showed "greater grey matter volume in posterior hippocampi and less grey matter volume in anterior hippocampi compared with controls." (Maguire et al., 2000, 2006a) "London taxi drivers performed significantly better than control subjects on tests assessing knowledge of London landmarks and their spatial relationships... taxi drivers were found to be significantly worse than control subjects on the delayed recall of the Rey-Osterreith complex figure." (Maguire et al., 2006a) Thu, 05 Feb 2009 09:23:11 +0000 http://cognitivefun.net/talk/post/11840#r_11955 It only seemed to aim to address one thing: whether taxi drivers give up something in becoming experts at city navigation. The results show a good likelihood that they do. But otherwise, this is one part of a series of studies done over a long time. It has some pretty interesting implications. London taxi drivers are a popular example when introducing plasticity (the other popular example is cortical thickening in the motor cortex mapping to the left pinky for violin players). When I learned about it, there was no discussion about the tradeoffs though. We should always be aware of potential downsides. Thu, 05 Feb 2009 09:09:29 +0000 http://cognitivefun.net/talk/post/11840#r_11954 I think this is highly likely. You could, for example, ask taxi drivers to memorize a novel city map, and compare it with controls. Taxi drivers would probably be very efficient at doing this. Also interesting would be how much generalization there is (if they start mixing up the new map with their old memories). Thu, 05 Feb 2009 09:09:29 +0000 http://cognitivefun.net/talk/post/11840#r_11953 Another possibility is a redistribution of resources, which would work in tandem with my previous suggestion involving environmental factors. Following the needs of the taxi drivers, their brains adapted in such a way as to store more information at the ready (what taxi drivers colloquially call "the knowledge") at the expense of needing to form new visual memories. But I wonder: would the taxi drivers outperform the controls in forming new memories for (skill-dependent?) new localities in an environment? In my opinion, this study doesn't go very deep at all. Wed, 04 Feb 2009 04:24:46 +0000 http://cognitivefun.net/talk/post/11840#r_11923 Sounds interesting - can you tell us more on this? Wed, 04 Feb 2009 01:01:40 +0000 http://cognitivefun.net/talk/post/11840#r_11919 They didn't address competition of resources. The idea of saturation is given as a possible interpretation of results, but is also noted as speculative, since they didn't find very clear relationships between hippocampal grey matter volume. I also agree with the anonymous comment above that the results could be very different if the taxi drivers were given time to "recoup." This doesn't seem to be addressed in the paper either. In terms of the "natural tendencies" of taxi drivers (or expert-level training at specific tasks), this finding is telling though. Maguire seems to have been doing a series of these studies, which all seem to show some form of tradeoff for expertise. Tue, 03 Feb 2009 08:55:29 +0000 http://cognitivefun.net/talk/post/11840#r_11908 This seems plausible, i.e., some form of competition could be taking place due to automatization. Like in the Stroop test, what slows one down is the automatizated lexical recognition, which competes with the color word association. We'll have to see if they addressed this in the paper. Tue, 03 Feb 2009 08:33:55 +0000 http://cognitivefun.net/talk/post/11840#r_11907 Rain man --> Kim Peek (who is not autistic, however) Exactly. But the peg-system is a well-known technique that ordinary folks can use to increase their storage capacity. I think a suitable explanation for the loss of storing ability for taxi drivers resides in the fact that they had no need to store new data -- their environment dictated (what I am will to assume) a temporary loss in their ability to effectively store new visual inputs. I'm willing to bet that they would regain their ability, within normal performance parameters, given some time outside of their day-job, to recoup. Plasticity is always the culprit, I say. Mon, 02 Feb 2009 09:29:08 +0000 http://cognitivefun.net/talk/post/11840#r_11885 good point like rain man? he apparently remembers everything he reads... ridiculous! Mon, 02 Feb 2009 06:26:24 +0000 http://cognitivefun.net/talk/post/11840#r_11871 I wouldn't say there is necessarily a larger limit with a higher gF. Plenty of individuals exist with low gF and have excellent memorization skills (even aside from autistic savants, neurotypicals can use various strategies to multiply storing capacity). Sun, 01 Feb 2009 05:19:50 +0000 http://cognitivefun.net/talk/post/11840#r_11856 Neuropsychologia. 2009 Jan 7. [Epub ahead of print]Click here to read Links Navigational expertise may compromise anterograde associative memory. Woollett K, Maguire EA. Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, London WC1N 3BG, UK. Grey matter volume increases have been associated with expertise in a range of domains. Much less is known, however, about the broader cognitive advantages or costs associated with skills and their concomitant neuroanatomy. In this study we investigated a group of highly skilled navigators, licensed London taxi drivers. We replicated findings from previous studies by showing taxi drivers had greater grey matter volume in posterior hippocampus and less grey matter volume in anterior hippocampus compared to matched control subjects. We then employed an extensive battery of tests to investigate the neuropsychological consequences of being a skilled taxi driver. Their learning of and recognition memory for individual items was comparable with control subjects, as were working memory, retrograde memory, perceptual and executive functions. By contrast, taxi drivers were significantly more knowledgeable about London landmarks and their spatial relationships. However, they were significantly worse at forming and retaining new associations involving visual information. We consider possible reasons for this decreased performance including the reduced grey matter volume in the anterior hippocampus of taxi drivers, similarities with models of aging, and saturation of long-term potentiation which may reduce information-storage capacity. ...can it go? i like the idea that knowing more allows more to be known, via classifcation/categorization/abstraction, which may make information storing more efficient, but i've never heard of an LTP saturation limit until now. in particular, if such a saturation barrier exists, i wonder how it correlates with baseline gF. +gF --> more efficient storing --> larger limit? Fri, 30 Jan 2009 10:42:50 +0000 http://cognitivefun.net/talk/post/11840#r_11841 how far... Fri, 30 Jan 2009 10:42:50 +0000 http://cognitivefun.net/talk/post/11840#r_11840