Short-Term Memory for Figure-Ground Organization in the Visual Cortex

Abstract

Summary Whether the visual system uses a buffer to store image information and the duration of that storage have been debated intensely in recent psychophysical studies. The long phases of stable perception of reversible figures suggest a memory that persists for seconds. But persistence of similar duration has not been found in signals of the visual cortex. Here we show that figure-ground signals in the visual cortex can persist for a second or more after the removal of the figure-ground cues. When new figure-ground information is presented, the signals adjust rapidly, but when a figure display is changed to an ambiguous edge display, the signals decay slowly – a behavior that is characteristic of memory devices. Figure-ground signals represent the layout of objects in a scene, and we propose that a short-term memory for object layout is important in providing continuity of perception in the rapid stream of images flooding our eyes.

Lack of color integration in visual short-term memory binding

“…Considerable evidence, however, could be gleaned from the memory and perception literature concerning figure/background representation. If we were to assume that the external colors of our stimuli could be interpreted as background colors, the effect appears to be consistent with evidence from the literature on memory (Isarida & Isarin, 2007;O'Herron & von der Heydt, 2009;Peterson & Grant, 2003) and perception (Hecht & Vecera, 2007;Vecera, 2004;Vecera & Palmer, 2006; but see Lester, Hecht, & Vecera, 2009). According to this literature, background information plays a crucial role in forming and accessing complex representation in memory and perception.…”

Figure–Ground Representation and Its Decay in Primary Visual Cortex

“…Unlike iconic memory, which is considerably shorter in duration (Coltheart, 1980;Di Lollo, 1977), persistence occurs because of camouflage rather than the complete removal of visual information specifying a previously salient object. This also makes persistence distinct from other recently proposed types of visual STM related to figure-ground segmentation (OʼHerron & von der Heydt, 2009;Sligte, Scholte, & Lamme, 2009). …”

Neurophysiology of learning in basic skills of laparoscopic surgery in undergraduate students

“…19 Learning is stored as persistent representation from one stage transitional working memory has a limited capacity and time range to a more durable and stable, with capacity for memory accesses versus future as a dynamic process in which information represented is subject to our personal experiences, the context of the learning environment, subsequent developments, service levels, stress and other factors. [20][21][22][23] The nature of synaptic changes within the memory storage has been studied using the phenomenon of longterm potentiation (LTP) in the hippocampus, where the long-term memory and most axons use glutamate as a neurotransmitter; The enhancement phenomenon is induced by activation of the NMDA receptors for glutamate, however during the membrane potential at rest, the pore NMDA is blocked by an ion Mg2 + and prevents the entry of Ca2 +, even in the presence of glutamate, glutamate to activate its receptors NMDA, the membrane must also be partially depolarized, causing Mg2 + leave the pore, and has glutamate binding to its receptors AMPA, or in response to a different neurotransmitter. 24 Under these conditions, glutamate causes the Ca2 + and Mg2 + to diffuse through the NMDA channel into the cell, the Ca2 + entering through NMDA receptor binds to calmodulin, a regulatory protein, this complex Ca2 + calmodulin, activates an enzyme call CaMKII (dependent protein kinase calmodulin) makes AMPA receptors to glutamate move to the plasma membrane of the postsynaptic neuron, i.e.…”