Topic: early visual cortex

Visual perception is perceived as continuous despite frequent disruptions in our visual environment. For example, internal events, such as saccadic eye-movements, and external events, such as object occlusion temporarily prevent visual information from reaching the brain. Combining evidence from these two models of visual disruption (occlusion and saccades), we will describe what information is maintained and how it is updated across the sensory interruption. Lina Teichmann will focus on dynamic occlusion and demonstrate how object motion is processed through perceptual gaps. Grace Edwards w

Visual perception is perceived as continuous despite frequent disruptions in our visual environment. For example, internal events, such as saccadic eye-movements, and external events, such as object occlusion temporarily prevent visual information from reaching the brain. Combining evidence from these two models of visual disruption (occlusion and saccades), we will describe what information is maintained and how it is updated across the sensory interruption. Lina Teichmann will focus on dynamic occlusion and demonstrate how object motion is processed through perceptual gaps. Grace Edwards wil

I will discuss the mechanisms that determine whether a weak visual stimulus will reach consciousness or not. If the stimulus is simple, early visual cortex acts as a relay station that sends the information to higher visual areas. If the stimulus arrives at a minimal strength, it will be stored in working memory. However, during more complex visual perceptions, which for example depend on the segregation of a figure from the background, early visual cortex’ role goes beyond a simply relay. It now acts as a cognitive blackboard and conscious perception depends on it. Our results also inspire ne

The involvement of early visual cortex during the short-term maintenance of visual information has been demonstrated in human fMRI studies [1,2]. However, evidence for sustained, stimulus-related neuronal firing in primate V1 is limited [3,4]. Recently, fading traces of visual information have been shown in the population code of primate V1 neurons for ~1.5 seconds after visual stimulus presentation in delayed match to sample and attention tasks [5]. The relatively long time-course of these fading memories make it unlikely to be a neural correlate of iconic memory [6], but may be related to “f

The exclusive attribution of working memory (WM) retention to persistent frontal activity [1,2] has been questioned by implications of spike-silent WM [3] in early visual cortex (EVC) [4,5,6]. Spike-silent WM might partly be explained by short-term plasticity (STP) [7], where perceptual encoding leaves a neural trace that can be retrieved using perturbation methods [8,9]. However, STP traces cannot easily withstand continual visual stimulation. In contrast, $modulatory$ top-down feedback [10] (i.e., altering spiking propensity without inducing spiking directly [11]) from frontal regions to EVC

Most mammalian species present topological maps of preference for the ori- entation of edges in their early visual cortex. However, despite the evidence that evolution has favoured topological map organisation in most species, a clear explanation for the functional role of such maps is lacking. Traditional approaches based on wiring minimisation are incomplete, showing how topology can reduce metabolic costs, but only after assuming a functional role of short- ranged like-tuned connectivity. In this work, we claim that topological maps are for reducing the complexity of the propagated informat

Perceptual filling-in occurs when a blank patch in the periphery of a texture field perceptually disappears after sustained fixation. This process may be mediated by horizontal spreading of activity in the early visual cortex. To test this proposal, we assessed if the oblique effect and the surround suppression effect, known to modulate activity in early visual cortex, modulates filling-in. In a psychophysics and eye-tracking experiment, 63 participants reported filling-in while attending peripherally to a grey rectangle on a dynamic texture field. We varied the orientation of elements in the