Perception Visual Integration

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Nov 14, 2013 (3 years and 6 months ago)

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Perception


Visual Integration


Task Name

Description

Cognitive Construct
Validity

Neural Construct Validity

Sensitivity to
Manipulation

Relationships to Behavior
and Schizophrenia

Psychometrics

Stage of Research

Motion
Perception


fMRI

The paradigm meas
ures
cortical activations during
visual motion perception,
using fMRI. It provides
assessments of both sensory
and cognitive systems.


(
Chen et al., 2008
)


MANUSCR
IPTS ON THE
WEBSITE:



Chen, Y., Grossman, E. D.,
Bidwell, L. C., Yurgelun
-
Todd, D., Gruber, S. A.,
Levy, D. L., et al. (2008).
Differential activation
patterns of occipital and
prefrontal cortices during
motion processing: evidence
from normal and
schizop
hrenic brains.
Cogn
Affect Behav Neurosci, 8
(3),
293
-
303.


Chen, Y., Palafox, G. P.,
Nakayama, K., Levy, D. L.,
Matthysse, S., & Holzman, P.
S. (1999). Motion perception
in schizophrenia.
Arch Gen
Psychiatry, 56
(2), 149
-
154.


When the visual motion
system
is damaged, both
perceptual and neural
response to motion signals
in primates will be deficient
(
Tootell et al., 1995
)
.


When the visual motion
system is damaged, both
perceptual and neural
response to motion signals
in primates will be deficient
(
Tootell et al., 1995
)
.

Psilocybin impairs
high
-
level but not
low
-
level motion
perception
(
Carter et
al., 2004
)
.


Contrast detection is
influenced by
antipsychotic
medications
(
Chen
et al., 2003
)
.

Application of this paradigm
has indicated deficient as
well excessive cortical
responses to visual signals
in schizophrenia patients
(
Chen et al., 2008
;
Chen,
Nakayama, Levy, Matthysse,
& Holzman, 1999
)
.

Not known

There is evidence
that this specific task
elicits deficits in
schizophrenia


We need to assess
psychome
tric
characteristics such
as test
-
retest
reliability, practice
effects, and
ceiling/floor effects
for this task.



We have evidence
that performance on
this task changes in
response to
psychological or
pharmacological
intervention.

Jittered
Orientation
Co
ntour
Integration
Task

(JOVI)


fMRI



In this test, participants are
presented with stimuli and
have to make a judgment as
to whether an oval shape
made up of separate Gabor
elements is pointing to the
left or the right. The
orientation of the contour
ele
ments (tangent to the line
1) Various versions of this
test have been valida
ted in
humans, where
psychophysical
manipulations of a single
parameter (e.g., signal
-
noise, contour element
orientation, etc) lead to
predicted changes in task
Data from patients, non
-
patient human studies, and
from monkey studies have
shown that the test
activates intermediate

visual
cortex regions, and that the
degree of activation is
strongly linked to the degree
to which the integrity of the

In a recent fMRI study
(
S. M.
Silverstein et al., 2009
)
,
sensitivity of early visual
cortex
regions to the jitter
manipulation (reduction in
good continuation of the
contour) was found in areas
V1
-
V4, but not beyond (e.g.,
IT). Moreover, as predicted,
Psychometric
characteristics for
both the behavioral
and imaging version
of this tasks are
currently being
examined.


Practice effects (over
There is eviden
ce
that this specific task
elicits deficits in
schizophrenia at
both the behavioral
and neural levels.


We have some
information on the
or shape, and jittered to
reduce perception of the
contour) is manipulated
across blocks of trials.
Increasing jitter places
increasing demands on
visual integration
mechanisms.


(
Kovacs, Kozma, Feher, &
Benedek, 1999
)

(
Kovacs, Polat, Pennefather,
Chandna, & Norcia, 2000
)

(
Kozma
-
Wiebe et al., 2006
)

(
Pennefather,

Chandna,
Kovacs, Polat, & Norcia,
1999
)


(
S. Silverstein et al., 2006
;
S.
M. Silverstein et al.
, 2009
)


MANUSCRIPTS ON THE
WEBSITE:


Silverstein, S., Uhlhaas, P.
J., Essex, B., Halpin, S.,
Schall, U., & Carr, V. (2006).
Perceptual organization in
first episode schizophrenia
and ultra
-
high
-
risk states.
Schizophrenia Research,
83
(1), 41
-
52.


Silverstein, S. M., Berten, S.,
Essex, B., Kovacs, I.,
Susmaras, T., & Little, D. M.
(2009). An fMRI examination
of visual integration in
schizophrenia.
J Integr
Neurosci, 8
(2), 175
-
202.


.




performance. 2) Test
findings are consistent with
models from computational
neuroscience and
t
heoretical neurobiology.
3) Findings using this task
can not be accounted for in
terms of attention, memory,
or other cognitive factors.

contour is altered: as jitter is
increased slightly to
moderately there are
increases in activity as
demand on integrative
mechanisms i
s increased;
however, once jitter
increases to the point where
the contour can no longer
be perceived, activation
level drops significantly.

(
Chandna, Pennefather,
Kovacs, & Norcia, 2001
)

(
Kiorpes & Bassin, 2003
)

(
Kourtzi, Tolias, Altmann,
Augath, & Logothetis, 2003
)

schizophrenia patients
demonstrated reduced
activation compared to
controls in regions
subservi
ng integration, but
not those involved in feature
detection: there were no
group differences in V1, but
there were large differences
in V2, V3, and V4. There
were no group differences in
higher areas such as IT.
These data replicated earlier
non
-
clinical

human and
monkey studies that used
similar stimuli (but not with a
2AFC response format) and
found the neural basis of
contour integration to be
primarily in V2 and V3 (LOC)
(Altmann, Bülthoff, Kourtzi,
2003, Current Biology;
Kourtzi, Tolias, Altmann,
Aug
ath, Logothetis, 2003,
Neuron).

2, 3, and 4 days
depending on the
study) have been
minimal in past
studies by the
K
ovacs and
Silverstein groups,
and have not differed
across control,
schizophrenia and
schizoaffective
groups (Silverstein et
al. 2006, Cognitive
Neuropsychiatry).
Test
-
retest reliability
is currently being
measured as part of
the CNTRACS
consortium projec
t.
Inter
-
rater reliability in
healthy and
amblyopic samples
for detection
thresholds was high,
as reported in
Pennefather et al.
(1999, Spatial
Vision).


Ceiling and floor
effects have not been
demonstrated in fMRI
data using the JOVI.
The current versi
on
of the task has added
conditions to the
middle
-
difficulty
range, to maximize
power for between
-
group
discriminations.
Performance on this
task also correlates
negatively with
performance on the
Ebbinghaus illusion
psychometric
characteristics such
as test
-
retest
reliability, practice
effects, and
ceiling/floor effects
for this task.



We need to
determine whether
performance on this
task changes in
response to
psychological or
pharmacological
intervention.

task, in which a
visual integratio
n
deficit leads to a
reduced context
-
based illusion
-

supporting the
hypothesis that
scores do not reflect
a generalized deficit
(Uhlhaas et al. 2006,
Perceptual grouping
in disorganized
schizophrenia.
Schizophrenia
Research, 145, 105
-
117).

Kanisza
Square
Illusion


fMRI

Parametric modulation of
perceptual grouping using
the Kanisza square illusion in
an imaging parad
igm that
probes the degree of sensory
interactions among multiple
stimuli.


(
Beck & Kastner, 2005
;
McMains

& Kastner, 2010
)


MANUSCRIPTS ON THE
WEBSITE:


Beck, D. M., & Kastner, S.
(2005). Stimulus context
modulates competition in
human extrastriate cortex.
Nat Neurosci, 8
(8), 1110
-
1116.


McMains, S. A., & Kastner,
S. (2010). Defining the

units
of competition: influences of
perceptual organization on
competitive interactions in
human visual cortex.
J Cogn
Neurosci, 22
(11), 2417
-
2426.



The representation of
visual information in cortex
depends strongly on the
degree to which stimuli
compe
te with each other.
This neural competition is
an automatic process.
However, it has been
shown to provide an
important neural principle
for attentional selection to
operate on (e.g. Duncan's
& Desimone's biased
competition theory). In the
proposed para
digm we
have investigated the
influences of bottom
-
up
factors in the form of
perceptual grouping on the
level of competition. This
paradigm informs about the
integrity of perceptual
mechanisms in visual
cortex.

The representation of visual
information in
cortex
depends strongly on the
degree to which stimuli
compete with each other.
This neural competition is
an automatic process.
However, it has been shown
to provide an important
neural principle for
attentional selection to
operate on (e.g. Duncan's &
Desimone's biased
competition theory). In the
proposed paradigm we
have investigated the
influences of bottom
-
up
factors in the form of
perceptual grouping on the
level of competition. This
paradigm informs about the
integrity of perceptual
mechanisms in

visual cortex
(
Beck & Kastner, 2005
;
McMains & Kastner, 2010
)
.

Unknown

This paradigm looks at two
automati
c processes that
shape how we perceive the
world: neural competition
and perceptual grouping in
visual cortex. There is
evidence that perceptual
organization is impaired in
schizophrenia.

Both paradigms have
been used in several
published papers,
and they

are very
robust. Subjects
simply maintain
fixation, since we
measure automatic
processes (i.e. no
practice, ceiling
effects and the like).

There is evidence
that similar tasks
elicit deficits in
schizophrenia at the
behavioral and
neural level.


We nee
d to assess
psychometric
characteristics such
as test
-
retest
reliability, practice
effects, and
ceiling/floor effects
for the imaging and
behavioral data.


We need to study
whether or not
performance on this
task changes in
response to
psychological or
pha
rmacological
intervention.


REFERENCES:


Beck, D. M., & Kastner, S. (2005). Stimulus context modulates competition in human extrastriate cortex.
Nat Neurosci, 8
(8), 1110
-
1116.

Carter, O. L., Pettigrew, J. D., Burr, D. C., Alais, D., Ha
sler, F., & Vollenweider, F. X. (2004). Psilocybin impairs high
-
level but not low
-
level motion perception.
Neuroreport, 15
(12), 1947
-
1951.

Chandna, A., Pennefather, P. M., Kovacs, I., & Norcia, A. M. (2001). Contour integration deficits in anisometropic am
blyopia.
Invest Ophthalmol Vis Sci, 42
(3), 875
-
878.

Chen, Y., Grossman, E. D., Bidwell, L. C., Yurgelun
-
Todd, D., Gruber, S. A., Levy, D. L., et al. (2008). Differential activation patterns of occipital and prefrontal cortices du
ring motion processing: evi
dence from
normal and schizophrenic brains.
Cogn Affect Behav Neurosci, 8
(3), 293
-
303.

Chen, Y., Levy, D. L., Sheremata, S., Nakayama, K., Matthysse, S., & Holzman, P. S. (2003). Effects of typical, atypical, and

no antipsychotic drugs on visual contrast d
etection in schizophrenia.
Am J Psychiatry,
160
(10), 1795
-
1801.

Chen, Y., Nakayama, K., Levy, D. L., Matthysse, S., & Holzman, P. S. (1999). Psychophysical isolation of a motion
-
processing deficit in schizophrenics and their relatives and its association w
ith impaired smooth
pursuit.
Proc Natl Acad Sci U S A, 96
(8), 4724
-
4729.

Kiorpes, L., & Bassin, S. A. (2003). Development of contour integration in macaque monkeys.
Vis Neurosci, 20
(5), 567
-
575.

Kourtzi, Z., Tolias, A. S., Altmann, C. F., Augath, M., & Log
othetis, N. K. (2003). Integration of local features into global shapes: monkey and human FMRI studies.
Neuron, 37
(2), 333
-
346.

Kovacs, I., Kozma, P., Feher, A., & Benedek, G. (1999). Late maturation of visual spatial integration in humans.
Proceedings of
the National Academy of Sciences, 96
, 12204
-
12209.

Kovacs, I., Polat, U., Pennefather, P. M., Chandna, A., & Norcia, A. M. (2000). A new test of contour integration deficits in

patients with a history of disrupted binocular experience during visual develop
ment.
Vision Res, 40
(13), 1775
-
1783.

Kozma
-
Wiebe, P., Silverstein, S., Feher, A., Kovacs, I., Ulhaas, P., & Wilkniss, S. (2006). Development of a Word
-
Wide Web based contour integration test: Reliablity and validity.
Computers in Human Behavior,
22
, 971
-
9
80.

McMains, S. A., & Kastner, S. (2010). Defining the units of competition: influences of perceptual organization on competitive

interactions in human visual cortex.
J Cogn Neurosci, 22
(11), 2417
-
2426.

Pennefather, P. M., Chandna, A., Kovacs, I., Polat, U
., & Norcia, A. M. (1999). Contour detection threshold: repeatability and learning with 'contour cards'.
Spat Vis, 12
(3), 257
-
266.

Silverstein, S., Uhlhaas, P. J., Essex, B., Halpin, S., Schall, U., & Carr, V. (2006). Perceptual organization in first episo
de schizophrenia and ultra
-
high
-
risk states.
Schizophrenia Research, 83
(1), 41
-
52.

Silverstein, S. M., Berten, S., Essex, B., Kovacs, I., Susmaras, T., & Little, D. M. (2009). An fMRI examination of visual in
tegration in schizophrenia.
J Integr Neurosci, 8
(2), 175
-
202.

Tootell, R. B. H., Reppas, J. B., Kwong, K. K., Malach, R., Born, R. T., Brady, T. J., et al. (1995). Functional analysis of
human MT and related visual cortical areas using magnetic resonance imaging.
Journal of
Neuroscience, 15
(April), 3215
-
3230.