powerpoint on the evolution of the brain

7/25/2019 Powerpoint on the Evolution of the Brain

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Early history of neuroscience

1700 B.C. : Egyptian hieroglyph writing for "brain."

Aristotle384-3B.C.

Belie!e the #in was lo$ate in theheart% whi$h $ontaine all e#otionsan thin&ing. 'he brain was li&e araiator (se to $ool the bloo. )*eare s#arter than other ani#alsbe$a(se we $ool o(r bloo better witha bigger brain.+

,alen130-00

A..

Belie!e the brain re$ei!es sensoryinfor#ation an is responsible for#otor $ontrol% (sing the #e$hanis#of (i energies.

Belie!e the brain was the seat oftho(ght an e#otion.

/ippo$rates40-370

B.C.


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eonaro a2in$i14-11

5s this a rawing of the brain on the 6istineChapel $eiling

i$helangelo147-14


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Descartes thought that the carrier

of information was the cerebral spinal fluid(CSF) flowing through nerve tubes.

Descartes reasoned that, when the fire

burns the man's toe, it stretches the skin,

which tugs on a nerve tube leading to the

brain.

n response to the tug, a valve in aventricle of the brain opens and CSF flows

down the tube, filling the leg muscles and

causing them to contract. and pull the toe

back from the fire.

Descartes's theor! was inaccurate, but he isolated the three basic "uestions that

underlie a behavioral response to stimulation#

$. %ow do our nerves detect a sensor! stimulus and inform the brain about it&

. %ow does the brain decide what response should be made& . %ow does the brain command muscles to move to produce a behavioral

n *arl! ccount of +eflees+ene Descartes

$-/0$/-1


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2hrenolog!# old and new

Fran3 4oseph 5all

$6-70$77


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9ierre 9a(lBro$a184-1880

5n 18% he showe that a patientwith a stro&e in his left frontal lobe$o(l (nerstan lang(age b(t $o(l

not spea&.'his area is now $alle Bro$as area.

i&e Bro$a% *erni$&e ha asi#ilar stro&e !i$ti#. B(t thisti#e the patient $o(l spea&b(t #ae no sense. 'he

a#age area was aro(nwhere the te#poral anparietal lobes #eet in theposterior part of the lefthe#isphere.

Carl*erni$&e1848-104

;(n$tional lo$ali


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1. ;rontal8 =E>e$(ti!e? f(n$tions% e$ision #a&ing%planning

. 9arietal8 5ntegrates sensations

into boy $oorinates

3. 'e#poral8 /earing% lang(age%

#e#ory% s#ell% taste

4. @$$ipital8 2is(al pro$essing

e h(#an $erebral $orte> has fo(r #aor lob


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9evels of organi3ation


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,ross Anato#y of the er!o(s 6yste#

: )C6+ 'he brain anthe spinal $ortogether #a&e (p the

$entral ner!o(ssyste#

: )96+ All ner!epro$esses an ne(rons

o(tsie the C6.

6ensory re$eptors

(s$les

5nternal organs


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,ross Anato#y of the er!o(s 6yste#

: Central er!o(s 6yste# )C6+

8'he brain an spinal $or: 9eripheral er!o(s 6yste# )96+

8 6o#ati$ i!ision: $on!eys

sensory infor#ation to the C6

an #otor infor#ation

fro# the C6

to the #(s$les.

8 A(tono#i$ i!ision: enables

the C6 to go!ern

the wor&ings of the

internal organs

)e.g.% heartbeat% respiration+.


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E!ol(tion of Brains an of Beha!ior@rigin of Brain Cells an Brains

: espite the age of the Earth )4. billion years+%brain $ells an brains are (ite re$entaaptations.8 ;irst for#s of life: 3. billion years ago )A to D+

8 ;irst brain $ells: 700 #illion years ago )A to tah+

8 ;irst brain: 0 #illion years ago )A to as 2egas+

8 ;irst h(#an-li&e brain: #illion years ago ) #iles+

8 oern h(#an brain: 00%000 years ago )1F4 #ile+

8Do(r lifespan: 100 years )#aybe+ )abo(t 4 in$hes+


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;e re ll like, and ;e re ll Different


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: @nlyAnimalia

)Gingo#+ $ontainsspe$ies with #(s$lesan ner!o(ssyste#s.

: (s$les an ner!o(ssyste#s e!ol!etogether to (nerliethe for#s of#o!e#ent)beha!ior+ thatisting(ish #e#bers

of the ani#al&in o#.

'a>ono#y of oern /(#ans


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E!ol(tion of Brains an of Beha!iorE!ol(tion of Ani#als /a!ing er!o(s 6yste#s

;i!e iHerent &ingo#s


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E!ol(tion of Brains an of Beha!iorE!ol(tion of er!o(s 6yste#ser!e net:

6i#plest ofall ner!o(ssyste#swithsensoryan #otorne(rons.

6eg#ente ner!e tr(n&:

Bilaterally sy##etri$al)the sa#e on both siesof the boy+.

,anglia: 6tr($t(res that

rese#ble an f(n$tionso#ewhat li&e a brain.

@ften lin&e in a $hain.

Brain: 'he

$horate phyl(#isplays thegreatest egree ofen$ephali


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E!ol(tion of the /(#an Brain an Beha!ior/(#ans: e#bers of the 9ri#ate @rer

;eat(res $o##on to pri#ates:

: E>$ellent $olor !ision.

: Eyes in front of fa$e: enhan$esepth per$eption.

: s(ally only one infant perpregnan$yI infants re(ire #ore$are.

: arge brains for s&ille#o!e#ents an so$ial beha!ior.

/(#ans an$hi#pan


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E!ol(tion of the /(#an Brain an Beha!ior

: Early ho#inis were a#ong

the Krst pri#ates to showistin$tly h(#an$hara$teristi$s% in$l(ingwal&ing (pright an (singtools.

: 'heir brain was the si


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E!ol(tion of the /(#an Brain an Beha!ior'he ;irst /(#ans

: Homo habilis)=hanyh(#an?+8 #illion years agoI in

Afri$a.

8 ae si#ple stone tools.

: Homo erectus)=(prighth(#an?+8 1. #illion years agoI in

E(rope an Asia.8 ore sophisti$ate tools

than H. habilis.

rthals $o-e>iste )an interbre+ with /. sapiens )we share 4L of o(r genes+


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: 'he brain ofAustralopithecuswas abo(t thesa#e si


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More important than absolute brain size is theEncephalization Quotient (EQ):

eas(re of brain si


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Encephalization Quotients for arange of

species shows that smarteranimalshave larger EQs

!ote: crows and bats have similarEQs to mon"eys

#ll of the hominids (both living (H.sapiens) and e$tinct (H. habilisand H. erectus) have large EQsH. sapienshave the largest EQ(dolphins come in at a closesecond)

Question: how did our brains getso large (relative to our bodysize)%

/ th h b i l t b l


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-- C5A'E C/A,E:

Abo(t 8 DA% the ,reat Nift 2alley e#erge

$reating a ry lans$ape where o(r an$estor li!e.

8'his le to fewer trees an #ore tall grasses.

8*e were for$e fro# an e>isten$e in the trees to one on the gro(n.

8BE/A25@N C/A,E: 6tarte to stan (p to see o!er the grasses.

8Allowe (s to see approa$hing preators )big $ats+.

8;ree o(r hans to hol an $arry st(H% gather foo an allowe (s to be#ore $reati!e an e!elop tools an weapons. )*hy are we )#ostly+ right hane. /int:where is o(r heart+

8Began to eat fr(it instea of grasses.

;r(it-eaters ha!e larger brains than leaf eaters

8;ining fr(it is harer than Kning eible lea!esOnees a larger brain.

8,oo $olor !ision e!elope to is$ern ripe fro# (nripe fr(it. ,oo !isionnees a big brain.

8eee larger brain to re#e#ber whi$h trees ha the best fr(it )an whi$hseason is best to Kn goo fr(it+% whi$h trees ha goo fr(it in the pre!io(syear% an whi$h trees ha alreay been pi$&e. Eye-han $oorinationi#pro!e% so$iali

powerpoint on the evolution of the brain

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