Schizophrenia is a serious mental disorder that affects about 1 % of the world’s population. UB researchers have identified a deficit in the perception of contrast in people with this disease. According to a review of more than six hundred studies, these patients would have altered the ability to see differences in the intensity of light between adjacent areas, which allows us to identify forms, textures and details in the environment. These results could help decipher dysfunctions in the neural and computational mechanisms of schizophrenia. In addition, this perceptual alteration could also be explored as a non -invasive biomarker potential for the diagnosis or monitoring of this disorder. However, the authors underline the need to carry out more studies to confirm this relationship and clarify the role they play in this visual alteration other factors such as medication.
Researchers Cristina de la Malla and Daniel Linares
The article, published in the magazine Schizophrenia Bulletin, is signed by researchers Daniel Linares and Cristina de la Malla, together with the master’s student Aster Joostens, of the Vision and Control Group of the action of the Faculty of Psychology and the Institute of Neurosciences of the UB (Ubneuro).
A key indicator of visual function
The symptoms of schizophrenia are characterized by alterations of thought and behavior, such as loss of contact with reality, delusions or hallucinations, but there are also anomalies in the perception of visual stimuli, such as for example deficits in color perception or contrast. Understanding these anomalies can give clues about how alterations in information processing contribute to the symptoms characteristic of schizophrenia. «The perception of contrast is one of the most fundamental abilities of vision, since without it we could not properly perce faces or read, ”explains the research team, which belongs to the Department of Cognition, Development and Psychology of Education.
The neural mechanisms involved in this alteration could be related to glutamate levels, a neurotransmitter that is considered to play a central role in the pathogenesis of the disease. «A decrease in this neurotransmitter can cause a reduction in neural activity in the brain areas responsible for processing the contrast. Consequently, a decrease in contrast sensitivity, although not of great magnitude, may reflect an underlying deterioration in the glutamericgal system of affected people, ”details the specialists.
Therefore, contrast sensitivity tests could be “a valuable tool to identify individuals with schizophrenia that demonstrate a more pronounced dysfunction in this neurotransmission pathway. For example, these patients could be ideal candidates for clinical trials that evaluate medications that are specifically directed to the glutamergic signal, ”they underline.
Unravel the impact of medication and attention
The results of the research show an alteration in the perception of the contrast of great magnitude in people with schizophrenia, but also that this dysfunction could be influenced by other factors. “In the study we have identified a relationship with the dose of antipsychotics administered, which suggests that the alteration could be due, at least partially, for the purposes of medication,” they emphasize.
“In the study we have identified a relationship with the dose of administered antipsychotics, which suggests that the alteration could be due, at least partially, for the purposes of medication,” they emphasize
Likewise, it would be crucial to know in more detail what paper represents attention, since none of the studies reviewed has taken into account that patients could do the least concentrated test, although, according to experts, it is known that these people are more prone to suffer attentional lapse. «A deficit when doing a perceptual or cognitive task can derive from a specific deterioration in the processes that the task is designed to evaluate, but it could also reflect a more generalized cognitive impairment, such as lapsus of attention, which could be estimated by The proportion of errors in very easy tests, ”they explain. The fact that the studies have not taken into account this factor “opens the possibility that these lapses contribute to the deficit that has been observed,” they add.
In this way, to determine if the alteration is caused directly by the disease and to be able to use this indicator as a biomarker of psychosis, the researchers underline the need to develop new studies with experimental designs that allow to unlink perceptive deficits of attention and that include populations with symptoms Psychotics, without medication or with little. “In this line, we currently measure contrast sensitivity in patients with anti-NMDAR encephalitis, a disease in which there is also psychotic symptoms, using a paradigm that includes control tests to monitor your attention,” they conclude.
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