Visual processing abnormalities in schizophrenia are commonly found, and contribute to poor social function. There is evidence that

schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...

affects

perception Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous system ...

of contrast and

motion In physics, motion is the phenomenon in which an object changes its position with respect to time. Motion is mathematically described in terms of displacement, distance, velocity, acceleration, speed and frame of reference to an observer and mea ...

, control of

eye movements Eye movement includes the voluntary or involuntary movement of the eyes. Eye movements are used by a number of organisms (e.g. primates, rodents, flies, birds, fish, cats, crabs, octopus) to fixate, inspect and track visual objects of inte ...

, detection of visual contours, and recognition of faces or facial expressions. The specificity of many visual processing abnormalities in schizophrenia is still an area of active debate within the scientific community.

Perception of contrast

Contrast sensitivity

Contrast is a feature of visual stimuli that characterizes the difference in

brightness Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light. In other words, brightness is the perception elicited by the luminance of a visual target. The perception is not linear to luminance, ...

between dark and light regions of an image. Perception of contrast is affected by the temporal frequency and spatial frequency properties of a stimulus, and the sensitivity to contrast in

sine wave A sine wave, sinusoidal wave, or just sinusoid is a curve, mathematical curve defined in terms of the ''sine'' trigonometric function, of which it is the graph of a function, graph. It is a type of continuous wave and also a Smoothness, smooth p ...

stimuli is characterized by the

contrast sensitivity Contrast is the contradiction in luminance or colour that makes an object (or its representation in an image or display) distinguishable. In visual perception of the real world, contrast is determined by the difference in the colour and brightn ...

function. Contrast sensitivity has been shown to be impaired in schizophrenia. There is evidence that these impairments may be more severe among people with predominantly negative symptoms, or those who are not

medicated A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and rel ...

. Butler and colleagues have proposed that people with schizophrenia may have a specific deficit in the magnocellular visual processing pathway, and

electroencephalography Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex ...

(EEG) data have been presented that may support this view. Results from pharmacological studies in cats have demonstrated the role of NMDA in contrast perception of magnocellular-tuned stimuli. Application of drugs that deactivate this

glutamate Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can syn ...

receptor type led to reduced neural responses in the visual system of cats, and some argue this suppression is similar to the reduced behavioral responses observed among people with schizophrenia. They claim these results are consistent with the

glutamate hypothesis of schizophrenia The glutamate hypothesis of schizophrenia models the subset of pathologic mechanisms of schizophrenia linked to glutamatergic signaling. The hypothesis was initially based on a set of clinical, neuropathological, and, later, genetic findings point ...

, which proposes that dysfunction in this neurotransmitter system leads to abnormal neural activity underlying this disorder. Skottun and colleagues dispute the magnocellular deficit theory however, saying that there is not enough evidence from different research groups to support it, and that the experiments focused on this topic have shown very mixed results.

Surround suppression

The perceived contrast of a stimulus is sometimes suppressed when another stimulus is presented surrounding it, an effect known as

surround suppression Surround suppression is where the relative firing rate of a neuron may under certain conditions decrease when a particular stimulus is enlarged. It has been observed in electrophysiology studies of the brain and has been noted in many sensory neuro ...

(see Figure 1), which is similar to the

simultaneous contrast A contrast effect is the enhancement or diminishment, relative to normal, of perception, cognition or related performance as a result of successive (immediately previous) or simultaneous exposure to a stimulus of lesser or greater value in the s ...

illusion. In schizophrenia, estimations of perceived contrast in surround suppression are less suppressed than for healthy adults. Further, the magnitude of this perceptual suppression effect has been shown to correlate with the concentration of GABA (γ-aminobutyric acid), an

inhibitory neurotransmitter A neurotransmitter is a signaling molecule secreted by a neuron to affect another cell across a synapse. The cell receiving the signal, any main body part or target cell, may be another neuron, but could also be a gland or muscle cell. Neur ...

, in the

visual cortex The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalamus and ...

. These results may illustrate the role of GABA in mechanisms that regulate the overall level of neural activity in visual cortex, and it has been suggested that such mechanisms may be disrupted in schizophrenia. Such a disruption would be consistent with the GABA hypothesis of schizophrenia, which states that dysfunctional GABAergic inhibition may disrupt neural activity in subjects with this disorder, and this in turn may lead to visual processing abnormalities.

Motion processing

Motion perception Motion perception is the process of inferring the speed and direction of elements in a scene based on visual, vestibular and proprioceptive inputs. Although this process appears straightforward to most observers, it has proven to be a difficult pr ...

is an important visual function and occurs from the earliest stages of cortical visual processing, with individual neurons being tuned to a preferred direction of motion. The cortical area MT (medial temporal cortex, also known as V5) plays a significant role in motion processing, and deactivation of this region using Transcranial magnetic stimulation can affect perception of motion. Subjects with schizophrenia have shown abnormalities in perceptual judgments of motion, speed and direction, with deficits in these judgments generally being reported. It has been suggested that these findings are related to the aforementioned magnocellular deficit purported to exist in this disorder. Inhibition of motion perception by the addition of a surround stimulus has also been examined in schizophrenia, with one group finding evidence both of impaired motion perception and weaker perceptual suppression effects in schizophrenia. This agrees with the findings mentioned previously related to weaker suppression of perceived contrast in this disorder. However, another recent report has disputed this finding, instead showing evidence consistent with stronger surround influence on motion perception in schizophrenia.

Eye movements

Eye movements Eye movement includes the voluntary or involuntary movement of the eyes. Eye movements are used by a number of organisms (e.g. primates, rodents, flies, birds, fish, cats, crabs, octopus) to fixate, inspect and track visual objects of inte ...

are important behaviors for locating and tracking objects in the visual world. Two of the major types of eye movements are

saccades A saccade ( , French for ''jerk'') is a quick, simultaneous movement of both eyes between two or more phases of fixation in the same direction.Cassin, B. and Solomon, S. ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishi ...

and smooth pursuit. Saccades are very rapid and precise eye movements between two positions, and are important in establishing fixation. Smooth pursuit on the other hand, allows the viewer to track a moving object along its trajectory within the visual field. Deficits in eye movement behavior among people with schizophrenia have been reported since the beginning of the 20th century. Genetic factors are believed to be involved in these abnormalities, as unaffected relatives show similar dysfunction. Specifically, saccade abnormalities have been observed in this disorder, with people showing changes in saccade rate, amplitude and accuracy. Such deficits have been linked to medication with lithium, as well as to damage in frontal lobe regions. Further, people with schizophrenia often exhibit errors in smooth pursuit eye movements. The neural correlates of smooth pursuit behavior in schizophrenia have been studied using

functional Magnetic Resonance Imaging Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area o ...

(fMRI), with abnormal activation having been observed in multiple cortical regions implicated in motion processing, such as

Frontal Eye Fields The frontal eye fields (FEF) are a region located in the frontal cortex, more specifically in Brodmann area 8 or BA8, of the primate brain. In humans, it can be more accurately said to lie in a region around the intersection of the middle fronta ...

and area MT. Some have speculated that errors in smooth pursuit in this disorder may depend on deficits in frontal lobe processing, such as errors in anticipating the direction of stimulus motion, and that this in turn may be consistent with

working memory Working memory is a cognitive system with a limited capacity that can hold information temporarily. It is important for reasoning and the guidance of decision-making and behavior. Working memory is often used synonymously with short-term memory, ...

deficits in schizophrenia. Others have disputed this claim, presenting evidence instead pointing to the aforementioned deficits in motion processing, and abnormalities in cortical area MT as a possible source of smooth pursuit errors. In this experiment, it was found that motion perception and smooth pursuit task performance were correlated, but no relationship between measures of smooth pursuit and

attention Attention is the behavioral and cognitive process of selectively concentrating on a discrete aspect of information, whether considered subjective or objective, while ignoring other perceivable information. William James (1890) wrote that "Atte ...

was observed.

Contour detection

Detecting visual contours, edges, or boundaries is an important function in human and

computer vision Computer vision is an interdisciplinary scientific field that deals with how computers can gain high-level understanding from digital images or videos. From the perspective of engineering, it seeks to understand and automate tasks that the hum ...

which facilitates figure-ground segmentation and object recognition. Contour integration depends on a subject’s ability to link representations of separate visual stimuli into a coherent percept. Subjects with schizophrenia have been shown to perform worse than healthy adults on tasks that depend on contour integration, and these deficits may be related to factors such as illness severity, chronicity, and degree of disorganized symptoms. In these experiments, subjects often viewed stimuli that could be connected to form a coherent perception of a line, like a simplified

connect the dots Connect the dots (also known as connect-the-dots, dot to dot, or join the dots) is a form of puzzle containing a sequence of numbered dots. When a line is drawn connecting the dots the outline of an object is revealed. The puzzles frequently c ...

puzzle. It is worth noting that in general, the magnitude of visual processing abnormalities (such as abnormal contour detection performance) in schizophrenia are fairly small. Therefore, it may be necessary to examine experimental data from a large number of subjects in order to observe difference between healthy adults and those with schizophrenia using statistical methods. It has been proposed that weaker lateral excitation due to deficient NMDA-receptor functioning could disrupt neural processing, and that this might underlie problems with contour integration in schizophrenia. This idea is consistent with the

, as dysfunction in this neurotransmitter system may explain the symptoms observed. Presentation of collinear stimuli flanking a target can enhance responses to the target in cortex, an effect known as flanker or collinear facilitation, which has been shown to be weaker in those with schizophrenia than in unaffected adults or those with

bipolar disorder Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that last from days to weeks each. If the elevated mood is severe or associated with ...

. Publications from multiple research groups indicate that those with schizophrenia perform more poorly than healthy adults when asked to identify contours composed of separated line segments embedded in backgrounds made up of randomly oriented segments. This includes evidence from an

fMRI Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area o ...

experiment indicating abnormally reduced activation in visual areas V2-4. Another group used

EEG Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex ...

to examine

illusory contour Illusory contours or subjective contours are visual illusions that evoke the perception of an edge without a luminance or color change across that edge. Illusory brightness and depth ordering often accompany illusory contours. Friedrich Schumann i ...

processing deficits in schizophrenia. They found decreased amplitude and altered source location for the P1 component in patients, which they claim reflects abnormal dorsal stream processing in this disorder.

Crowding phenomenon

Crowding Crowding (or visual crowding) is a perceptual Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception inv ...

refers to the phenomenon where recognition of visual stimuli presented in the

periphery Periphery or peripheral may refer to: Music *Periphery (band), American progressive metal band * ''Periphery'' (album), released in 2010 by Periphery * "Periphery", a song from Fiona Apple's album '' The Idler Wheel...'' Gaming and entertainm ...

is impaired by the presence of other nearby objects (sometimes called "flankers"). Abnormal crowding has been observed in schizophrenia, with different groups reporting stronger or weaker crowding effects.

Gaze shifts

During

gaze shift The visual cortex of the brain is the area of the cerebral cortex that processes visual perception, visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in ...

s, for example when an object appears in the periphery, human usually move both their eye and head to capture the object of interest. In experiments, in which participants needed to shift their gaze to detect a visual target, people with schizophrenia exhibit abnormal eye-head coordination, and no modulation of saccadic latency (the delay between onset of the stimulus in the periphery and the start of the gaze shift) occurred, which is usually task dependent in healthy controls as they adjust to different task in terms of saccadic latency.

Perception of faces and facial emotions

Faces

Face perception is a function of the visual system which is critical for social behavior. People with schizophrenia have shown abnormalities in tasks designed to probe facial processing and recognition. Specifically, performance deficits have been observed in this disorder when subjects were asked to identify degraded pictures of faces, and the deficits observed were specific to those with predominantly disorganized symptoms. Another experiment using the same stimuli during

found poorer performance and slower reaction times among those with schizophrenia, as well as abnormalities in beta band activity. The authors state that these results are related to deficits in long range coordination of neural activity, as described for

contour detection Contour may refer to: * Contour (linguistics), a phonetic sound * Pitch contour * Contour (camera system), a 3D digital camera system * Contour, the KDE Plasma 4 interface for tablet devices * Contour line, a curve along which the function has a ...

. Another experiment using EEG and structural MRI to examine facial processing abnormalities in schizophrenia found decreased

N170 The N170 is a component of the event-related potential (ERP) that reflects the neural processing of faces, familiar objects or words. Furthermore, the N170 is modulated by prediction error processes. When potentials evoked by images of faces are co ...

component responses, and this was correlated with decreased gray matter volumes in the

fusiform gyrus The fusiform gyrus, also known as the ''lateral occipitotemporal gyrus'','' ''is part of the temporal lobe and occipital lobe in Brodmann area 37. The fusiform gyrus is located between the lingual gyrus and parahippocampal gyrus above, and the inf ...

. There is evidence that the fusiform face area is a visual cortical region that may be specialized for detecting faces. The authors of this study conclude that their data support a specific face processing deficit in schizophrenia. However, another study using fractured images of faces found that people with schizophrenia were better than healthy adults at identifying images of famous people that had been distorted. These experiments state that this may be evidence of weaker "configural" processing in schizophrenia, who instead may rely more on local image

features Feature may refer to: Computing * Feature (CAD), could be a hole, pocket, or notch * Feature (computer vision), could be an edge, corner or blob * Feature (software design) is an intentional distinguishing characteristic of a software item ...

for face identification, as these were preserved in their image manipulation.

Facial emotions

Recognizing emotional expressions in images of human faces is a particularly important component of face perception with clear implications in human social interactions. People with schizophrenia reportedly perform poorly compared with healthy adults when asked to identify facial emotions. Some researchers have claimed that this is not a deficit specific to facial emotion perception per se, but rather evidence of a generalized deficit or overall poorer task performance in schizophrenia. However, others have argued that a review of the literature shows evidence of an additional specific deficit in processing negative emotions, such as anger and fear, among those with schizophrenia. In addition, evidence has been presented of a link between a specific emotion processing deficit in schizophrenia and the volume of

temporal lobe The temporal lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe ...

structures, including

and middle temporal gyrus, as measured using MRI.

Visual backward masking

In visual backward masking (VBM) a briefly presented target is followed by a mask, which decreases performance on the target. VBM is a powerful experiment for schizophrenia research. It allows for control over timing at millisecond level, there are well-supported theories of the underlying mechanisms, and it can be easily studied using

and

. Not only patients but also their unaffected siblings show strong and reproducible masking deficits, thus masking deficits have been suggested as an

endophenotype In genetic epidemiology, endophenotype (or intermediate phenotype) is a term used to separate behavioral symptoms into more stable phenotypes with a clear genetic connection. The concept was coined by Bernard John and Kenneth R. Lewis in a 1966 pap ...

for schizophrenia.

Trigger hypothesis

In the early stages of the disease, and in untreated patients, hypersensitivity to low spatial frequencies has been documented. During the further course (and medication) of schizophrenia, this hypersensitivity turns into hyposensitivity and begins to affect other spatial frequencies of visual perception. Alterations to the visual signal, which are largely inconsistent over the course of schizophrenia (remission and relapse phases), may lead to the formation of inconsistent internal models of the world. These signal alterations (noise-to-signal ratios) are associated with fluctuations in

Dopamine Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic compound, organic chemical of the catecholamine and phenethylamine families. Dopamine const ...

and Acetylcholin levels, decreased activity of inhibitory GABAergic interneurons, and hypofunction of NMDAr associated with gradual loss of cell populations in the precortical visual circuit. The volatile and noisy signal from the visual periphery may then act as an amplifier of primarily decreased connectivity within frontal areas, which may then prograde retrogradely to lower cortical areas of the visual information processing circuit.

References

{{reflist , refs= {{cite journal , author = Abel, L. A., Levin, S., & Holzman, P. S. , year = 1992 , title = Abnormalities of Smooth Pursuit and Saccadic Control in Schizophrenia and Affective Disorders , journal = Vision Research , volume = 32 , issue = 6 , pages = 1009–1014 , doi = 10.1016/0042-6989(92)90002-Z , pmid = 1509692, s2cid = 37248315 {{cite journal , last1=Butler , first1=P. D. , last2=Martinez , first2=A. , last3=Foxe , first3=J. J. , last4=Kim , first4=D. , last5=Zemon , first5=V. , last6=Silipo , first6=G. , last7=Mahoney , first7=J. , last8=Shpaner , first8=M. , last9=Jalbrzikowski , first9=M. , last10=Javitt , first10=D. C. , title=Subcortical visual dysfunction in schizophrenia drives secondary cortical impairments , journal=Brain , publisher=Oxford University Press (OUP) , volume=130 , issue=2 , date=1 February 2007 , issn=0006-8950 , doi=10.1093/brain/awl233 , doi-access=free , pages=417–430 , pmid=16984902 , pmc=2072909 {{cite journal , last1=Butler , first1=Pamela D. , last2=Silverstein , first2=Steven M. , last3=Dakin , first3=Steven C. , title=Visual Perception and Its Impairment in Schizophrenia , journal=Biological Psychiatry , publisher=Elsevier BV , volume=64 , issue=1 , year=2008 , issn=0006-3223 , doi=10.1016/j.biopsych.2008.03.023 , pages=40–47 , pmid=18549875 , pmc=2435292 {{cite journal , author = Chen, Y., Levy, D. L., Sheremata, S., & Holzman, P. S. , year = 2004 , title = Compromised late-stage motion processing in schizophrenia , journal = Biological Psychiatry , volume = 55 , issue = 8 , pages = 834–841 , doi = 10.1016/j.biopsych.2003.12.024 , pmid = 15050865, s2cid = 10006874 {{cite journal , author = Chen, Y., Norton, D., & Ongur, D. , year = 2008 , title = Altered center-surround motion inhibition in schizophrenia , journal = Biological Psychiatry , volume = 64 , issue = 2 , pages = 74–77 , doi = 10.1016/j.biopsych.2007.11.017 , pmid=18206855 , pmc=2483430 {{cite journal , author = Dakin, S., Carlin, P., & Hemsley, D. , year = 2005 , title = Weak suppression of visual context in chronic schizophrenia , journal = Current Biology , volume = 15, issue = 20 , pages = R822–R824 , doi=10.1016/j.cub.2005.10.015 , pmid=16243017, doi-access = free {{cite journal , last1=Foxe , first1=John J. , last2=Murray , first2=Micah M. , last3=Javitt , first3=Daniel C. , year = 2005 , title = Filling-in in schizophrenia: a high-density electrical mapping and source-analysis investigation of illusory contour processing , journal = Cerebral Cortex , volume = 15 , issue = 12 , pages = 1914–27 , doi = 10.1093/cercor/bhi069 , pmid = 15772373 , doi-access = free {{cite journal , author = Goghari, V. M., MacDonald, A. W., & Sponheim, S. R. , year = 2011 , title = Temporal Lobe Structures and Facial Emotion Recognition in Schizophrenia Patients and Nonpsychotic Relatives , journal = Schizophrenia Bulletin , volume = 37 , issue = 6 , pages = 1281–1294 , doi = 10.1093/schbul/sbq046 , pmid = 20484523 , pmc = 3196942 {{cite journal , author = Gonzalez-Burgos, G., & Lewis, D. A. , year = 2008 , title = GABA neurons and the mechanisms of network oscillations: implications for understanding cortical dysfunction in schizophrenia , journal = Schizophrenia Bulletin , volume = 34 , issue = 5 , pages = 944–61 , doi = 10.1093/schbul/sbn070 , pmid = 18586694 , pmc = 2518635 {{cite journal , author = Heeger, D. J. , year = 1992 , title = Normalization of Cell Responses in Cat Striate Cortex , journal = Visual Neuroscience , volume = 9 , pages = 181–197 , doi = 10.1017/S0952523800009640 , pmid = 1504027 , issue = 2, s2cid = 22804285 {{cite journal , author = Hong, L. E., Tagamets, M., Avila, M., Wonodi, I., Holcomb, H., & Thaker, G. K. , year = 2005 , title = Specific motion processing pathway deficit during eye tracking in schizophrenia: a performance-matched functional magnetic resonance imaging study , journal = Biological Psychiatry , volume = 57 , issue = 7 , pages = 726–732 , doi = 10.1016/j.biopsych.2004.12.015 , pmid = 15820229, s2cid = 20560856 {{cite journal , author = Hubel, D. H. , author2 = Wiesel, T. N. , year = 1962 , title = Receptive fields, binocular interaction and functional architecture in the cat's visual cortex , journal = The Journal of Physiology , volume = 160 , issue = 1 , pages = 106–154.2 , doi = 10.1113/jphysiol.1962.sp006837, pmid = 14449617 , pmc = 1359523 {{cite journal , author1 = Joshua, N. , author2 = Rossell, S. , year = 1962 , title = Configural face processing in schizophrenia , journal = Schizophrenia Research , volume = 112 , issue = 1–3 , pages = 99–103 , pmid = 19419842 , doi = 10.1016/j.schres.2009.03.033, s2cid = 39343088 {{cite journal , author = Keri, S., Antal, A., Szekeres, G., Benedek, G., & Janka, Z. , year = 2002 , title = Spatiotemporal visual processing in schizophrenia , journal = Journal of Neuropsychiatry and Clinical Neurosciences , volume = 14 , issue = 2 , pages = 190–6 , doi = 10.1176/appi.neuropsych.14.2.190 , pmid = 11983794 {{cite journal , author = Keri, S., Kelemen, O., Benedek, G., & Janka, Z. , year = 2005 , title = Lateral interactions in the visual cortex of patients with schizophrenia and bipolar disorder , journal = Psychological Medicine , volume = 35 , pages = 1043–1051 , doi = 10.1017/S0033291705004381 , pmid = 16045070 , issue = 7, s2cid = 12984126 {{cite journal , author1=Kerr, S.L. , author2=Neale, J.M. , name-list-style=amp , year = 1993 , title = Emotion Perception in Schizophrenia: Specific Deficit or Further Evidence of Generalized Poor Performance , journal = Journal of Abnormal Psychology , volume = 102 , issue = 2 , pages = 312–318 , doi = 10.1037/0021-843X.102.2.312 , pmid = 8315144 {{cite journal , author = Kim, D., Wylie, G., Pasternak, R., Butler, P. D., & Javitt, D. C. , year = 2006 , title = Magnocellular contributions to impaired motion processing in schizophrenia , journal = Schizophrenia Research , volume = 82 , issue = 1 , pages = 1–8 , doi = 10.1016/j.schres.2005.10.008 , pmid = 16325377 , pmc = 2045640 {{cite journal , author = Kraehenmann, R., Vollenweider F.X., Seifritz E., Kometer, M. , year = 2012 , title = Crowding deficits in the visual periphery of schizophrenia patients , journal = PLOS ONE , volume = 7 , issue = 9 , pages = e45884 , doi = 10.1371/journal.pone.0045884 , pmid = 23049884 , pmc=3458825, bibcode = 2012PLoSO...745884K , doi-access = free {{cite journal , author = Lewis, D. A., Hashimoto, T., & Volk, D. W. , year = 2005 , title = Cortical Inhibitory Neurons and Schizophrenia , journal = Nature Reviews Neuroscience , volume = 6 , pages = 312–324 , doi = 10.1038/nrn1648 , pmid = 15803162 , issue = 4 , s2cid = 3335493 {{cite journal , author=Mandal, M. K. , author2=Pandey, R. , author3=Prasad, A. B. , year = 1998 , title = Facial expressions of emotions and schizophrenia: A review , journal = Schizophrenia Bulletin , volume = 24 , issue = 3 , pages = 399–412 , doi = 10.1093/oxfordjournals.schbul.a033335 , pmid = 9718632, doi-access = free {{cite journal , author = O'Donnell, B. F., Bismark, A., Hetrick, W. P., Bodkins, M., Vohs, J. L., & Shekhar, A. , year = 2006 , title = Early stage vision in schizophrenia and schizotypal personality disorder , journal = Schizophrenia Research , volume = 86 , issue = 1–3 , pages = 89–98 , doi = 10.1016/j.schres.2006.05.016 , pmid = 16829048, s2cid = 31845762 {{cite journal , last1=Onitsuka , first1=Toshiaki , last2=Niznikiewicz , first2=Margaret A. , last3=Spencer , first3=Kevin M. , last4=Frumin , first4=Melissa , last5=Kuroki , first5=Noriomi , last6=Lucia , first6=Lisa C. , last7=Shenton , first7=Martha E. , last8=McCarley , first8=Robert W. , year = 2006 , title = Functional and structural deficits in brain regions subserving face perception in schizophrenia , journal = American Journal of Psychiatry , volume = 163 , issue = 3 , pages = 455–62 , doi = 10.1176/appi.ajp.163.3.455 , pmid = 16513867 , pmc = 2773688 {{cite journal , author1=Robol V. , author2=Tibber M.S. , author3=Anderson E.J. , author4=Bobin T. , author5=Carlin P. , author6=Shergill S.S. , author7=Dakin S.C. , year = 2013 , title = Reduced crowding and poor contour detection in schizophrenia are consistent with weak surround inhibition , journal = PLOS ONE , volume = 8 , issue = 4 , pages = e60951 , doi = 10.1371/journal.pone.0060951 , pmid = 23585865 , pmc=3621669, bibcode=2013PLoSO...860951R , doi-access=free {{Erratum, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6564015/, checked=yes, doi=10.1371/journal.pone.0218483, pmc=6564015, pmid=31194845 {{cite journal , author = Salem, J.E., Kring, A.M., & Kerr, S.L. , year = 1996 , title = More Evidence for Generalized Poor Performance in Facial Emotion Perception in Schizophrenia , journal = Journal of Abnormal Psychology , volume = 105 , issue = 3 , pages = 480–483 , doi = 10.1037/0021-843X.105.3.480 , pmid = 8772021, citeseerx = 10.1.1.317.9472 {{cite journal , author = Silverstein, S. M., Berten, S., Essex, B., Kovács, I., Susmaras, T., & Little, D. M. , year = 2009 , title = An fMRI Examination of Visual Integration in Schizophrenia , journal = Journal of Integrative Neuroscience , volume = 8 , issue = 2 , pages = 175–202 , doi = 10.1142/S0219635209002113 , pmid = 19618486 {{cite journal , author = Silverstein, S. M., Kovács, I., Corry, R., & Valone, C. , year = 2000 , title = Perceptual organization, the disorganization syndrome, and context processing in chronic schizophrenia , journal = Schizophrenia Research , volume = 43 , issue = 1 , pages = 11–20 , doi = 10.1016/S0920-9964(99)00180-2 , pmid = 10828411, s2cid = 36005234 {{cite journal , last1=Skottun , first1=Bernt C. , last2=Skoyles , first2=John R. , title=Contrast sensitivity and magnocellular functioning in schizophrenia , journal=Vision Research , publisher=Elsevier BV , volume=47 , issue=23 , year=2007 , issn=0042-6989 , doi=10.1016/j.visres.2007.07.016 , pages=2923–2933 , pmid = 17825350 , doi-access = free {{cite journal , author = Slaghuis, W.L., & Thompson, A. K. , year = 2003 , title = The effect of peripheral visual motion on focal contrast sensitivity in positive-and negative-symptom schizophrenia , journal = Neuropsychologia , volume = 41 , issue = 8 , pages = 968–980 , doi = 10.1016/S0028-3932(02)00321-4 , pmid = 12667532, s2cid = 21972610 {{cite journal , author = Slaghuis, Walter L. , year = 2004 , title = Spatio-temporal luminance contrast sensitivity and visual backward masking in schizophrenia , journal = Experimental Brain Research , volume = 156 , pages = 196–211 , doi = 10.1007/s00221-003-1771-3 , pmid = 14752582 , issue = 2, s2cid = 23072195 {{cite journal , last1=Stuve , first1=T. A. , last2=Friedman , first2=L. , last3=Jesberger , first3=J. A. , last4=Gilmore , first4=G. C. , last5=Strauss , first5=M. E. , last6=Meltzer , first6=H. Y. , title=The relationship between smooth pursuit performance, motion perception and sustained visual attention in patients with schizophrenia and normal controls , journal=Psychological Medicine , publisher=Cambridge University Press , volume=27 , issue=1 , year=1997 , issn=0033-2917 , doi=10.1017/s0033291796004230 , pages=143–152 , pmid=9122294 , s2cid=23106085 {{cite journal , author = Tadin, D., Kim, J., Doop, M. L., Gibson, C., Lappin, J. S., Blake, R., & Park, S. , year = 2006 , title = Weakened Center-Surround Interactions in Visual Motion Processing in Schizophrenia , journal = Journal of Neuroscience , volume = 26 , issue = 44 , pages = 11403–11412 , doi = 10.1523/JNEUROSCI.2592-06.2006 , pmid = 17079669, pmc = 6674537 , doi-access = free {{cite journal , author = Tadin, D., Silvanto, J., Pascual-Leone, A., & Battelli, L. , year = 2011 , title = Weakened Improved Motion Perception and Impaired Spatial Suppression following Disruption of Cortical Area MT/V5 , journal = Journal of Neuroscience , volume = 31 , issue = 4 , pages = 1279–83 , doi = 10.1523/JNEUROSCI.4121-10.2011 , pmid = 21273412 , pmc = 3078722 {{cite journal , author = Uhlhaas, P. J., Linden, D. E. J., Singer, W., Haenschel, C., Lindner, M., Maurer, K., & Rodriguez, E. , year = 2006 , title = Dysfunctional long-range coordination of neural activity during Gestalt perception in schizophrenia , journal = Journal of Neuroscience , volume = 26 , issue = 31 , pages = 8168–75 , doi = 10.1523/JNEUROSCI.2002-06.2006 , pmid = 16885230, pmc = 6673788 , doi-access = free {{cite journal , author = Uhlhaas, P. J., Phillips, W. A., Mitchell, G., & Silverstein, S. M. , year = 2006 , title = Perceptual grouping in disorganized schizophrenia , journal = Psychiatry Research , volume = 145 , issue = 2–3 , pages = 105–117 , doi = 10.1016/j.psychres.2005.10.016 , pmid = 17081620, s2cid = 21325572 {{cite journal , author = Yoon, J. H., Maddock, R. J., Rokem, A. S., Silver, M. A., Minzenberg, M. J., Ragland, J. D., & Carter, C. S. , year = 2010 , title = GABA Concentration Is Reduced in Visual Cortex in Schizophrenia and Correlates with Orientation-Specific Surround Suppression , journal = Journal of Neuroscience , volume = 30 , issue = 10 , pages = 3777–3781 , doi = 10.1523/JNEUROSCI.6158-09.2010 , pmid = 20220012 , pmc = 2846788 {{cite journal , author = Yoon, J. H., Rokem, A. S., Silver, M. A., Minzenberg, M. J., Ursu, S., Ragland, J. D., & Carter, C. S. , year = 2009 , title = Diminished Orientation-Specific Surround Suppression of Visual Processing in Schizophrenia , journal = Schizophrenia Bulletin , volume = 35 , issue = 6 , pages = 1078–1084 , doi = 10.1093/schbul/sbp064 , pmid = 19620601 , pmc = 2762622 {{cite journal , author = Schwab, S., Würmle, O., Razavi, N., Müri, R. M., & Altorfer, A. , year = 2013 , title = Eye-head coordination abnormalities in schizophrenia , journal = PLOS ONE , volume = 8 , issue = 9 , pages = e74845 , doi = 10.1371/journal.pone.0074845 , pmid = 24040351 , pmc=3769305, bibcode = 2013PLoSO...874845S , doi-access = free {{cite journal , author = Malsert, J., Guyader, N., Chauvin, A., & Marendaz, C. , year = 2012 , title = Having to identify a target reduces antisaccade latencies in mixed saccadic paradigms: A top-down effect released by tonic prefrontal activation? , journal = Psychological Research , volume = 3 , issue = 2 , pages = 105–111 , doi = 10.1080/17588928.2012.666965 , pmid = 24168691, s2cid = 205936260 Schizophrenia