La neuroimpresa - il contributo delle neuroscienze · cui viene bruciato più ossigeno. Di...
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La neuroimpresa -
il contributo delle
U.O.C. di Neurologia e Neurofisiopatologia Clinica e Strumentale
IRCCS Associazione Oasi Maria SS
INDIVIDUO (comportamento) SISTEMA APPARATO (S.N.C.) ORGANO (cervello) TESSUTO (nervoso) CELLULA (neurone) ORGANELLI (membrana) MACROMOLECOLE (geni)
F A T T A O M R B I I E N T A L I
The number of neurons in the brain varies dramatically from species to species
One estimate puts the human brain at about 100 billion neurons and 100 trillion
Another estimate is 86 billion neurons of which 16.3 are in the cerebral cortex and
69 in the cerebellum
By contrast, the nematode worm Caenorhabditis elegans has just 302 neurons
making it an ideal experimental subject as scientists have been able to map all of
the organism's neurons.
The fruit fly Drosophila melanogaster, a common subject in biology experiments,
has around 100,000 neurons and exhibits many complex behaviors.
Pierre Paul Broca
A cortical minicolumn is a vertical column through
the cortical layers of the brain, comprising perhaps
80120 neurons, except in the primate primary
visual cortex (V1), where there are typically more
than twice the number
There are about 2108 minicolumns in humans
From calculations, the diameter of a minicolumn is
about 2840 m
Cells in 50m minicolumn all have the same
receptive field; adjacent minicolumns may have
very different fields
Risonanza Magnetica Funzionale (fMRI)
La fMRI una tecnica che utilizza le propriet magnetiche dei nuclei degli atomi costituenti la materia e il
nostro corpo. I segnali di risonanza delle molecole magnetizzabili vengono misurati mediante laiuto di
campi magnetici e onde radio. Quando eseguiamo un compito alcune aree cerebrali specifiche vengono
reclutate per lo svolgimento del compito. Le aree che vengono reclutate nel compito sono anche quelle in
cui viene bruciato pi ossigeno. Di conseguenza varia il rapporto tra ossiemoglobina e deossiemoglobina
presenti nelle aree reclutate dallattivazione. Tale variazione viene rivelata dal segnale di risonanza
magnetica e tradotta in immagini utilizzabili in pratica. Queste aree, dal punto di vista del segnale di
risonanza, sono caratterizzate dal cosiddetto effetto BOLD (Blood Oxygenation Level Dependent).
personal and impersonal decision making
moral personal dilemma
moral impersonal dilemma
La teoria delleconomia normativa nel prendere decisioni sotto rischio assume
che i decisori combinino probabilit e valutazione (utilit) di possibili esiti in un
certo modo, per lo pi tipicamente con unattesa probabilit-pesata su possibili
Le nostre esperienze quotidiane ed evidenze empiriche, per, ci dicono che
sistematicamente violiamo la teoria normativa.
Un tipo di sistematica violazione della teoria normativa che le persone tendono
a pesare le probabilit obiettive in maniera non lineare.
I decisori spesso sovrastimano basse probabilit (ad es., lotterie) e sottostimano
Lalternativa principale alla teoria normativa (dellutilit attesa) la teoria della
prospettiva (Tversky e Kahneman, 1992).
Una delle componenti importanti della teoria della prospettiva la pesatura non
lineare della probabilit nella quale le probabilit obiettive (p) sono trasformate in
maniera non lineare in pesi di decisione w(p) attraverso una funzione di pesatura.
(Takahashi et al., 2010)
Il senso di avversione derivato dal perdere una certa quantit di denaro
sembra essere maggiore del piacere derivato dal guadagnare una quantit
Immaginiamo di partecipare al gioco della lancio della monetina: se uscir
testa vincer 100 euro, se uscir croce perder 100 euro. Vogliamo giocare?
La maggior parte della gente dir di no.
Se, per, il premio per la vincita viene aumentato a 200 euro e la potenziale
perdita rimane 100 euro, qualcuno accetter di giocare.
Questo significa che, tipicamente, le perdite hanno 2 volte limpatto di
equivalenti guadagni, una propriet detta avversione per la perdita.
decision making under uncertainty
(a) Aversive stimuli, whether
decision options that involve
increased risk or punishments
themselves, have frequently been
shown to activate insular cortex
(INS) and ventrolateral prefrontal
(b) Unexpected rewards modulate
activation of the striatum (STR),
particularly its ventral aspect, as
well as the medial prefrontal cortex
(c) Executive control processes
required for evaluation of uncertain
choice options are supported by
dorsolateral prefrontal cortex
(dlPFC) and posterior parietal
Contributo della 5-HT e della NA alla loss aversion
NA = loss aversion
5-HT = loss tolerance
(Takahashi et al., 2013)
(Takahashi et al., 2013)
NET = NE
atomoxetina (bloccante del NET) riduce il binding e aumenta la loss aversion:
possibili implicazioni nel gambling disease
X X X X risk experiment
- A single intranasal dose of 24 IU
Novartis; 3 puffs per nostril,
each with 4 IU oxytocin) or
placebo 50 min before the start of
the trust or the risk experiment
- Subjects were randomly assigned
to the oxytocin or placebo group
Both subjects receive an initial endowment of 12 monetary units (MU). The
investor can send 0, 4, 8 or 12 MU to the trustee. The experimenter triples each
MU the investor transfers. After the investors decision is made, the trustee is
informed about the investors transfer. Then the trustee has the option of
sending any amount between zero and his total amount available back to the
investor. For example, if the investor has sent 12 MU, the trustee possesses 48
MU (12 MU own endowment + 36 MU tripled transfer) and can, therefore
choose any back transfer from 0 to 48 MUs. The experimenter does not triple
the back transfer. The investorsfinal payoff corresponds to the initial
endowment minus the transfer to the trustee, plus the back transfer from the
trustee. The trustees final payoff is given by his initial endowment plus the
tripled transfer of the investor, minus the back transfer to the investor. At the
end of the experiment, the earned MU are exchanged into real money
according to a publicly announced exchange rate. Each subject made four
decisions in the same player role while paired with four different, randomly
selected interaction partners.
The investors average
transfer is 17% higher in the oxytocin
group (Mann-Whitney U-test;
z = -1.897, P = 0.029, one-sided)
The average transfer is 7.5 MU in
both groups (Mann-Whitney U-
test; z = 0.022, P = 0.983; two-
(Baron-Cohen et al., 2001)
Reading the Mind in the Eyes Test
- 30 healthy male volunteers aged 21 30 years (mean SD, 25.3 - 2.2)
- exclusion criteria were medical or psychiatric illness, use of medication,
substance abuse, and smoking
- a single dose of 24 IU oxytocin (Syntocinon spray, Novartis, Basel,
Switzerland) or placebo was administered intranasally 45 min before the
start of the RMET
- participants underwent both the oxytocin and the placebo conditions with a
1-week interval in a balanced within-subject design
- in the RMET, 36 pictures of the eye regions of different persons were
presented to the participants on a PC screen with 4 alternative labels
describing what the person displayed might be thinking or feeling at the
- drug and session effects were statistically tested using paired t tests; the
sequence effect of treatment was tested using analysis of variance for
repeated measures; the significance level was always set at p< .05;
statistical analyses were carried out using SPSS (Statistical Package for the
Social Sciences) 12.0 for Windows
- 68 males participated in the experiment with 34 of them
receiving OT and 34 receiving placebo
- mean age was 21.8 (SD 3.8)
- only male subjects because of the possibility of an
unintended miscarriage in females as well as the varying
effects of OT over the menstrual cycle
- exclusion criteria included significant medical or
psychiatric illness, medications that interact with OT, and
drug or alcohol abuse
- participants were infused by nasal inhaler with either 40 IU
of OT or normal saline of the same amount
- OT was allowed to load for 60 minutes prior to the UG and
In the ultimatum game (UG), decision-maker 1(DM1) was endowed
with $10 and was asked to offer a split of this money to DM2. DM2
has no endowment.
If DM2 accepted the split, the money was paid. But, if DM2 rejected
the split, both DMs earned nothing.
Participants were asked to make decisions as both DM1 and DM2,
with subsequent random assignment of roles. As DM2s, they
were asked to state the minimum amount they would accept from a
DM1. The rejection threshold was not reported to the other DMs.
By asking subjects for the minimum acceptable offer, the UG task
was designed to have participants consider how the DM2 in the
dyad would react to an offer (perspective taking).
A rejection of DM1s offer in the UG allowed DM2 to punish DM1 for
stingy offers, but at a cost.
We define a generous transfer in the UG as a DM1 offer that
exceeds the average minimum acceptable offer.
The dictator game (DG) is similar to the UG in that
DM1 has a $10 endowment and DM2 has nothing. The
difference in the DG is that DM2 has no choice he or
she must accept whatever DM1offers.
As a result, the DG does not compel DM1 to consider
how DM2 will feel about the split of benefits (reduced
The consensus view in experimental economics is that
the transfer in the DG is a measure of altruism.
The inclusion of both the UG and DG allows us to
dissociate generosity from altruism within subjects.
Each individual received 10 and was allowed to invest all or part of
it in a within-group pool, and in a between-group pool. Within-group
pool investments were multiplied by 1.5 and equally distributed
among in-group members (i.e., for each Euro invested, each
member received 0.50).
Within-group pool investments thus reflect in-group love the
motivation to benefit in-group members at a cost to oneself.
Between-group pool investments had the same consequence to the
in-group as within-group pool investments, but also reduced the
endowments of the three out-group members by a factor of 1.5 (i.e.,
for each Euro invested, each in-group member gained 0.50, and
each out-group member lost 0.50).
Between-group pool investments thus reflect out-group hate the
motivation to hurt the out-group at a cost to oneself