1200
1000
800
1. Durante il reaching con il
braccio sinistro si attiva
LeftTrap
600
V D _1
M
U
S
C
L
E
S
Controllo normale
A
C
T
I
V
I
T
Y
μV
400
2. During il reaching con il
braccio destro si attiva il
RightTrap
200
0
L
-200
R
M:
Lef tTrap
RightTRap
Normal
Left movement
Right movement - - - - - - Resting
..……….
M:
Lef tTrap
RightTRap
NonAHP
M:
Lef tTrap
RightTRap
AHP
R
NonAHP
1200
1000
1. Durante il
reaching sn si
attiva il LeftTrap
800
600
V D _1
M
U
S
C
L
E
S
A
C
T
I
V
I
T
Y
μV
2. Durante il reaching
ds si attiva il
RightTrap
400
200
0
L
-200
R
M:
Lef tTrap
RightTRap
Normal
Left movement
Right movement - - - - - - Resting
..……….
M:
Lef tTrap
RightTRap
NonAHP
M:
Lef tTrap
RightTRap
AHP
R
1200
1000
800
600
VD _1
M
U
S
C
L
E
S
A
C
T
I
V
I
T
Y
μV
400
200
0
-200
M:
Lef tTrap
RightTRap
Normal
Left movement
Right movement - - - - - - Resting
..……….
M:
Lef tTrap
RightTRap
NonAHP
M:
Lef tTrap
RightTRap
AHP
Paziente AHP.
1200
1. Durante il reaching sn si attiva il
LeftTrap
1000
800
2. Durante il reaching ds si attiva il
RightTrap
is activated
3. Durante
il reaching
sn il RightTrap è più
attivo del sn. Però la parte destra è
sempre più attiva della sinistra (anche
nella condizione di risposo;
probabilmente ‘an active process
induced by disinhibition, in order to
establish new compensatory pathways’
see Ghika et al., 1995; Cao et al., 1998)
V D _1
600
400
200
0
-200
M:
Lef tTrap
RightTRap
Normal
Left movement
Right movement
Resting
-------
..……….
M:
Lef tTrap
RightTRap
NonAHP
M:
Lef tTrap
RightTRap
AHP
CONCLUSION
 From the activity registered in the proximal
muscles of the affected side we can infer that AHP
patient had, similarly to normal subjects, the
intention to move
 Next question would be: is this intentional
response related to the operation of neural
mechanisms that govern normal motor behaviour so
to influence the motor performance of the intact hand
when the patients try to execute bimanual
movements?
We decided to use a paradigm proposed by Kelso and
coworkers in which the subjects had to reach for easy target
(near and large) and difficult target (far and small).
They found that
the Movement Time
was much shorter
for easy target than
for difficult target in
unimanual
performance.
However, when the two
conditions were combined
they did not find that the
limb producing a short
movement to an easy
target arrived earlier than
the limb producing the
difficult movement.
 there was a strong tendency for both movements to be
initiated and terminated synchronously. In particular, the
hand moving to the easy target slowed down when
moving with the hand going to the difficult target.
The question is: what happens when an hemiplegic
patient with anosognosia, who cannot move the
contralesional hand, but is convinced of being able
to move it, is asked to perform unimanual and
bimanual asymmetric movements?
We slightly modified this
paradigm to adapt it to right
brain-damaged patients. In the
Kelso et al. experiments
targets were positioned to the
right and left of the starting
positions. In our paradigm the
targets were positioned on the
radial plane to minimise the
interaction with visual neglect.
Hand (Left or Right)
difficult
easy
-normal subjects
Space (Near or Far)
Action (Unimanual, Ba, Bs)
-patient with AHP
RESULTS IN NORMAL SUBJECTS
1. LH and RH had
similar MT in
unimanual condition
Transport time for the left and right hand as function of Space and A ction
900
 Movement Time is
much shorter for easy
target
than
for
difficult target in
unimanual conditions.
800
M o vem en t T im e
700
600
500
400
1. In bimanual condition
the hands’ reaching is
simultaneous.
300
200
100
Action
Far
U
Ba
Left hand
Bs
Action
U
Ba
Bs
Near
Right hand
Conclusion: the hands were influenced by
the simultaneous acting of the other hand
in asymmetrical conditions.
2. In Ba conditions
 the hand that reaches
for near targets
slowed down.
Predictions
• When patients with AHP are asked to perform
bilateral reaching movements
No intention
They
should
not
attempt
bilateral
hands movements
No difference in the
MT of the R hand in
the
different
conditions
of
the
experiment
Intention
They should attempt
bilateral movements
 MT of the R hand in
the Unilateral and
Bilateral
conditions
should differ
Case report: Patient LM
41-year-old right-handed man
damage in the right hemisphere caused left
hemiplegia, left hemianaesthesia and severe personal
and extrapersonal left-sided neglect.
We tested him 71 days after the stroke
Well oriented in time and space
had no global reasoning or language problems. He
could readily understand and follow test instructions
and was very cooperative.
At the time of testing he still showed left
hemiplegia and left anaesthesia, whereas personal
and extrapersonal neglect were improved
He also showed a severe ansognosia for hes
hemiplegia  Like CR he believed that he was able
to use his left arm and hand and to walk and carry
out without any problem several daily activities
Patient and controls’ right hand
1600
- Also in patient LM
the action of the
right hand in near
space is influenced
by the simultaneous
‘perceived’ action of
the contralesional
plegic hand
1400
M o v e m e n t T im e
1200
1000
800
600
400
200
0
ACTION:
UR
Ba
Patient
Bs
ACTION:
UR
Ba
Controls
Bs
Far
Near
These experiments strongly suggest that AHP patients do
have the intention to move the plegic limb
The intention was not an abstract will related to the
previous knowledge of being able to move, but was
actually implemented in the muscles fibers activated
by the spared cortical circuits for motor programming
and movement execution
goes so far as to influence the motor parameter of
the right hand when the patients has the false belief of
simultaneously moving the left hand.
Next steps
 studiare aspetti bimanuali puramente motori
 studiare coinvolgimento distale attraverso lo studio
cinematico del grasping
1. aspetti bimanuali puramente motori
Berti and Pia, 2007
Anosognosia
affordances
Urge to move/intention
Goals/
Prior intention
Desired
state
compa
rator
Planner
(movement
selection)
Motor
awareness
C
x
Limb
World
Efference
copy
Forward model (Movement
predictor/predicted state)
B
Sense of agency
A Comparator
comp
arator
x
The discrepancy is
not detected
Sensory
Information/actual state
In A, the comparator; in B, the predictor; in C, the locus of emergence of
intention to move. According to our hypothesis:
1. a damage to the comparator that has to match the prediction with the
actual state of the system prevents the detection of the difference between
the movement/no movement conditions.
2. A part of the motor system functions normally. Patients have intentions
and make predicitons. This leads to the construction of a non-veridical
motor awareness that may represent the bases of the firm belief of being
still able to move.
Grazie a voi e a:
Lorenzo Pia
Department of Pyshcology, Turin University
Lucia Spinazzola
Gabriella Bottini
Department of Pyshcology, University of Pavia
Eraldo Paulesu
Department of Pyshcology, University of Milano Bicocca
Martina Gandola
Department of Pyshcology, University of Pavia
Nicola Smania
Rehabilitation Unit, Verona Hospital
Andrea Stracciari
Neurology Unit, Sant’Orsola Hospital, Bologna
affordances
Goals/
Prior intention
Motor
awareness
Sense of agency
Urge to
move/intention