On Disturbed Time Continuity in Schizophrenia: An Elementary Impairment in Visual Perception?

Abstract

Schizophrenia is associated with a series of visual perception impairments, which might impact on the patients' every day life and be related to clinical symptoms. However, the heterogeneity of the visual disorders make it a challenge to understand both the mechanisms and the consequences of these impairments, i.e., the way patients experience the outer world. Based on earlier psychiatry literature, we argue that issues regarding time might shed a new light on the disorders observed in patients with schizophrenia. We will briefly review the mechanisms involved in the sense of time continuity and clinical evidence that they are impaired in patients with schizophrenia. We will then summarize a recent experimental approach regarding the coding of time-event structure in time, namely the ability to discriminate between simultaneous and asynchronous events. The use of an original method of analysis allowed us to distinguish between explicit and implicit judgments of synchrony. We showed that for SOAs below 20 ms neither patients nor controls fuse events in time. On the contrary subjects distinguish events at an implicit level even when judging them as synchronous. In addition, the implicit responses of patients and controls differ qualitatively. It is as if controls always put more weight on the last occurred event, whereas patients have a difficulty to follow events in time at an implicit level. In patients, there is a clear dissociation between results at short and large asynchronies, that suggest selective mechanisms for the implicit coding of time-event structure. These results might explain the disruption of the sense of time continuity in patients. We argue that this line of research might also help us to better understand the mechanisms of the visual impairments in patients and how they see their environment.

How do abnormalities in the brain’s spontaneous activity translate into symptoms in schizophrenia? From an overview of resting state activity findings to a proposed spatiotemporal psychopathology

“…With such a shift we might expect that temporal binding windows in people with the condition be longer than those seen in healthy participants. This is in fact what is seen in schizophrenia, where patients show binding window lengths in simultaneity judgement tasks of up to 100 to 150 ms longer than are seen in controls (Giersch, Lalanne, Van Assche, & Elliott, 2013;Martin, Giersch, Huron, & van Wassenhove, 2013). Similar findings have also been reported in tasks where the order in which stimuli are presented must be reported.…”

Forming first impressions of others in schizophrenia: Impairments in fast processing and in use of spatial frequency information

“…This is consistent with previous studies showing delays in processing configural aspects of faces (Butler et al, 2008), increased reaction time in making social appraisals (Taylor et al, 2011), impaired early-stage processing of faces in electrophysiological studies (Turetsky et al, 2007; Wynn et al, 2013) that may be related to impaired structural encoding of faces (Turetsky et al, 2007), and possibly impaired time continuity in schizophrenia (Giersch et al, 2013). Thus, impairments in temporal processing also extend to the ability to make a first impression.…”

The phenomenology and cognitive neuroscience of experienced temporality

“…The importance of this distinction for our problem lies in the fact that while in the former case a time asymmetric order of causation cannot play any role (no temporal order is perceived), the latter raises the issue of the possible dependence of the temporal order on the causal order. In experiments assessing thresholds for the perception of non-simultaneity versus simultaneity, temporal resolution depends on the sensory system involved, the lowest threshold of detection being observed in the auditory modality is within 2 to 3 milliseconds (ms) (Lacker andTeuber 1973, Lotze et al 1999); the tactile and visual system have higher thresholds, in the range of tens of milliseconds (Elliott et al 2007, Giersch et al 2013, Kirman 1974, Poggel et al 2013.…”