道法自然 -抉择的自然计算

算盘寺

The decision-making offers several challenges to neurobiologists.

1. First,“Where” question ,Where does the decision actually occur , whether particular brain areas contribute

more specifically to decision processes than to sensory discrimination or motor preparation.

2. Second “How ” question? the mechanisms by which prior knowledge and expectations are combined

with current sensory data during ongoing decision processing 3. Third, “ What” question? , the processes that select the

appropriate information among competing alternatives upon which a decision should be informed in a particular context ( Michael L Platt,2002).

4. Fourth, again “ What” question ,the main molecules and information flow involved in D/C

From Bigelow JH. Dr Harlow's case of recovery from the passage of an iron bar through the head. American Journal of the Medical Sciences. 1850;20:13-22. Reproduced by permission of The MIT Press from An Odd Kind of Fame

Discovery of the front lobe’s function in project by chance

I n thi s wel l -wri tten, entertai ni ng book, Mal col m Macmi l l an descri bes the resul ts of hi s meti cul ous research of pri mary and secondary sources to i nvesti gate the ci rcumstances of Gage' s brai n i nj ury and the af termath. On September 13, 1848, 25-year-ol d Phi neas Gage was worki ng as the foreman of a rai l way constructi on gang prepari ng the bed for the Rutl and and Burl i ngton Rai l road near Cavendi sh, Vt. Af ter the expl osi ve powder was pl aced i n a hand-dri l l ed hol e i n the rock, the powder was packed i nto as smal l a space as possi bl e by use of a tampi ng i ron. Thi s tool was 3 feet 7 i nches l ong and 1¼ inches in diam eter at the packing end, tapered over a distance of about 1 foot to a diam eter of ¼ of an inch at the other end, and weighed 13½ pounds. Inadvertently, the tam ping iron hit the rock so as to cause a spark to ignite the explosive powder. Thus launched, the tam ping iron entered Gage's head point first im m ediately anterior to the angle of the m andible, exited through the posterior frontal bone near the coronal suture, and landed about 25 to 30 yards behind him . Gage was thrown on his back, had a few convulsive m ovem ents of his extrem ities, and, perhaps without losing consciousness, spoke within a few m inutes. In about 1½ hours, Gage cam e under the m edical and surgical care of a 28-year-old physician, John Harlow, who treated him for 73 days. M iraculously, Gage, at one point sem icom atose, survived a brain abscess and m eningitis (m y diagnoses from the descriptions) and was able to go hom e to New Ham pshire.

According to Harlow's 1868 account, Gage was not able to return to his form er em ploym ent because of a dram atic personality change. He was reported as using profane language and described, M acm illan writes, as "fitful, capricious, im patient of advice, obstinate, and lacking in deference to his fellows," irreverent, obstinate, and vacillating. Harlow stated: "Previous to his injury, though untrained in the schools, he possessed a well-balanced m ind, and was looked upon by those who knew him as a shrewd, sm art business m an, very energetic and persistent in executing all his plans of operation. In this regard his m ind was radically changed, so decidedly that his friends and acquaintances said he was 'no longer Gage.'" After traveling in the region, Gage, with his iron, appeared at P. T. Barnum 's Am erican M useum in New York City and then worked at a livery stable. In 1852, he m oved to Chile and worked caring for horses and driving a six-horse coach. Gage m oved to San Francisco, Calif, where his m other and sister had already m oved, in 1859 (based upon M acm illan's research) because of ill health. Gage died in 1860 (based upon M acm illan's exam ination of cem etery records, not 1861 as Harlow incorrectly stated) of status epilepticus. Because an autopsy was not perform ed, the exact dam age to Gage's brain is not known. In 1867, the fam ily perm itted exhum ation of the body and rem oval of the skull, which was donated, along with the tam ping iron, to what is now the W arren Anatom ical M useum of Harvard M edical School.

M acm illan nicely reviews the history of cerebral localization, including the 19th-century contributions of Gall ("organology" as he term ed it, not "phrenology" as his concepts were popularized), Hughlings Jackson, Ferrier, Broca, and m any others. At the tim e, Gage was fam ous as a survivor of a horrific injury, and his case played only a m inor role in debates over localization. M acm illan also discusses the value of Gage's case in the origins of m odern neurosurgery in suggesting that brain surgery could be survived and the view that m ental changes could be used as localizing signs for frontal lobe lesions. In sum m arizing the history of psychosurgery, the author dem onstrates that Gage's case did not contribute directly to the field or procedures such as prefrontal lobotom y.

Gambling task adopted by Antonio R. Damasio

Antoine Bechara et al. SCIENCE 1997,VOL 275:1293

From <Principle of Neural Science, ed by E.R.Kandel, J.H.Schwartz,T.M.Sessell,Third Edition,1991,p443

Picasso:woman with yellow hair(Dec.1931)

Picasso’s panting

(Nikos K.Logothetis,Single units and Conscious Vision,Phil.Trans.R.Soc.Lond.B.1998 353:1801-1818)

William Newsome put the monkey in dilemma and recorded the responses of neurons in macaque MT to stochastic

motion signals.

Newsome W. Vis. Neurosci. 1993,10:1157-1169.

(P. Lawrence “The Making of a Fly”)

Drosophila1mm

果蝇

Cited from Nature review neuroscience April 2003, volume 4:268 (M.Heisenberg)

FB

EB

EB

PB

“color/ shape” dilemma

Non-conflicting cues Conflicting cues

Individual flies were conditioned to choose a flight directionin accordance to the color and shape cues in the flight simulatorand testes with the color and shape cues reversed following the training

If PI9>0.0 front

Tang & Guo,2001,Science,294:1543

 It would be difficult to explain these behavioural abnormalities by defects in the olfactory system. But if they reflect independent mushroom body functions, what is their common denominator? It seems that decision-like processes are involved in all four situations. Increased perseverance in flies lacking mushroom bodies47, 48 indicates that the balance between maintaining the existing behaviour and switching to a new behaviour is offset. Decision-like processes might also be involved when the mushroom bodies protect short-term visual memory traces against context changes54 and when they contribute to making the strength of the current sensory signals the arbitrator between two competing memory templates55. If, indeed, ancient mushroom bodies had no calyces and no prominent olfactory input1, one would like to assume that their involvement in decision making is their original function and that they acquired their contribution to olfactory processing as a secondary trait. What, then, is this role in decision making, and what made the ancient mushroom bodies suited for their second task?

Finally, flies lacking mushroom bodies seem to have difficulties in resolving 'conflicting' situations. Flies are trained in the flight simulator to prefer, for instance, a blue T to a green inverted T. In the subsequent memory test they are confronted with a green T and a blue inverted T. Which one should they prefer? Avoidance of colour and pattern cues balance each other. Flies in this 'paradoxical' situation resolve the dilemma by taking the reliability of the current sensory information during retrieval into account55. They evaluate the actual 'sensory strengths' of the parameters (colour and height of centre of gravity) corresponding to the two memory traces, and respond only to the memory trace for which the current parameter has the higher saliency. In other words, at high colour saturation during retrieval they obey only the colours and disregard the patterns, whereas if colour saturation is low they respond only to the patterns. A sharp transition between 'high' and 'low' colour saturation is observed. As in the context experiment54, flies need between 15 and 30 seconds to suppress one or the other memory trace (S. Tang, personal communication). Flies without mushroom bodies do not show this suppression55 — irrespective of colour saturation, they show no avoidance of colours or patterns.

Nature Reviews Neuroscience 4, 266-275 (2003); doi:10.1038/nrn1074 [1057K] 

MUSHROOM BODY MEMOIR: FROM MAPS TO MODELS  Martin Heisenberg

Citation by M.Heisneberg

In <Nature Reviews>4,266-275(2003)

Decision/choice of WTB and CS flies

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comparison of choice behavior between WTB and CS

MEA

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REVERSE OF CS(ANGLE)

WTB(n=228) CS(n=221)

If PI9>0.3

ShitsDdc

GAL4-EnhancerTrapping & Region-Specific Gene Expression(Scott Waddell & William G.Quinn(Trends in Genetics 17(12)2001:719)

To explore the circuit and signal molecules responsible for Decision-Making

Flight simulator with warmer and cooler systems added in

GFP coexpression of DDC-Gal4(Dopa decarboxylase)

and 247-Gal4 in Drosophila

DDC-Gal4;UAS-GFP DDC-Gal4;247;UAS-GFP

(unpublished)

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0.8Choice behavior of UAS-shits1/+;Ddc-gal4/+ on different temperature

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position(visual angle) of the converted object

22-23℃(n=107) 30℃(n=103)

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Choice behavior of WTB under the temper of 29.5℃

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dopamine neurons seem to mediate decision in Drosophila

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The Perforcemance of th/shits1 in the Dilemma

th/shits1 at room 24oC (N=91)

th/shits1 at room 29.5oC (N=96)

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Expression of TH-Gal4

Ddc-Gal4 is used as a dopaminergic driver which is known to target serotonergic cells as well. Th-Gal4 (Tyrosine Hydroxylase) is specific of dopamine cells..

(unpublished)

Visu a l se n so r

M o to r syste m

Visu a l c e n te r:Le a rn in g & M e m o ry

D e c isio nm a ke r

Visu a l in p u t

Be h a vio ra l o u tp u t

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(unpublished)