Feedback connections and conscious vision

“These findings suggest that the visual cortex serves as a dynamic ‘‘blackboard’’ [10, 11] that is used during both bottom-up stimulus processing and top-down internal generation of mental content.”

“…in natural images, a purely bottom-up architecture has fundamental difficulties in identifying objects in all but the simplest circumstances (Bullier, 2001a, 2001b), something that was also learned from efforts in computer vision (Sharon, Galun, Sharon, Basri, & Brandt, 2006; Ullman,…”

“Moreover, subjects often reported that they released the button without explicit understanding of the photograph, which is in accordance with the common idea that feedback processing may be crucial for conscious image perception (Bullier, 2001; Lamme & Roelfsema, 2000; Pascual-Leone & Walsh, 2001).”

“Thus, the effects on P1 are very likely the result of feedback and interactive processing that can impact rapidly on very early stages of cortical processing (Bullier, 2001b); these mature very quickly, or are present from a young age.”

“Thus, the blackboard nature of the visual cortex, as discussed here, basically results from the feedback connections in the visual cortex (Van der Velde 1997; Bulier 2001 ).”

“This reciprocity is particularly evident in the visual system, where feedback from such high-level regions as AREA MT/V5 can influence neural activity at the earliest stages of cortical processing, including the PRIMARY VISUAL CORTEX (area V1; Ref”

“Currently, top-down connectivities are the focus of ongoing experiments seeking to explain the status of impaired conscious perception during anesthesia (Bullier 2001; Hochstein and Ahissar 2002; Meyer 2011, 2015).”

“An earlier study provided compelling support for Bullier’s (2001b) model.”

“tions from extrastriate cortical areas appear critical for visual awareness (17,18).”

“Of course, whether or not computational loops can be defined as ‘‘mandatory’’ depends on the particular function investigated and on what we regard as the visual system’s output: Here, we show that a feedforward pass can be sufficient in the case of rapid visual categorization, but the performance of other functions i…”

“Modal completion has been shown to elicit illusory responses in V1 (Lee and Nguyen, 2001), supporting the idea that whatever representation is present in V1 is what we “perceive” (Bullier, 2001).”

“For example, Lamme and others emphasize the necessity of feedback connections for attention and conscious perception (Bullier, 2001; Lamme et al., 1998).”

“On the other hand, results from functional imaging, transcranial magnetic stimulation, and lesion studies have been used to argue either that perception can depend specifically on neurons in the earliest levels of the visual cortex [10–15] or that neurons in all parts of the visual cortex can contribute equally to per…”

“The second hypothesis proposes that interactive activity based on reciprocal connections between the subcortical and cortical areas is important for stimulus recognition and attention (Bullier, 2001; Pessoa & Adolphs, 2010).”

“HYPOTHESIS AND THEORY ARTICLE published: 09 August 2013 doi: 10.3389/fpsyg.2013.00501 The efference cascade, consciousness, and its self: naturalizing the first person pivot of action control”

“These brain regions project to the medial part of orbitofrontal cortex (also called the mediodorsal system; Barbas, 1988; Carmichael & Price, 1995; Öngür, Ferry, & Price, 2003) within 80 ms in a feedforward sweep (Bullier, 2001; Lamme & Roelfsema, 2000; also see Bar et al., 2006; Rempel-Clower & Barbas, 2000; Rudrauf…”

“…described by a number of studies that show how frontal and dorsoparietal areas become active at latencies similar or even earlier than the primary visual cortex (Bullier, 2001a), allowing sufficient time to influence even early responses in V1 via fast feedback pathways (Foxe & Simpson, 2002).”

“order specialized areas are fed back to V1 to be integrated and then passed on to consciousness (Bullier 2001).”

“…contextual processing (Lamme 1995; Zipzer et al. 1996), and attentional modulation of processing (Mehta and Schroeder 2000; Mehta et al. 2000; Bullier 2001; Schroeder et al. 2001a, b), recruitment of low-level sensory areas into the cognitive-perceptual process is partially attributable to…”

“Although in a strong form a bottom-up hierarchical model has been challenged (Felleman and Van Essen 1991; Hubel and Wiesel 1998; Schmolesky et al. 1998; Bullier 2001a; Hochstein and Ahissar 2002; Van Essen, 2005), hierarchy is still considered a major anatomical and functional principle in vision.”

“To date, several attempts have beenmade in order to solve this heterogeneous body of evidence, with the proposition of feedback loops from higher visual areas to V1 being one of them (Bullier, 2001; Lamme, 2004).”

“Therefore, whether visual imagery is mediated by feedback from later visual areas (Bullier, 2001) and how this relates to the debate over the involvement of early visual cortex (Kosslyn and Thompson, 2003) remains to be investigated.”

“Although V1 receives most of the retinal input (90%), there are other cortical areas that receive smaller proportions of retinal input from the thalamus (LGN, i.e., Bridge et al., 2008), which are able to respond simultaneously or even earlier than V1 (Bullier, 2001; Silvanto et al., 2005).”

“If so, this finding would support the view that higher visual areas feed back into lower visual areas that act as Bactive blackboards^ (Bullier, 2001).”

“However, it is now widely recognised that in addition to this, the brain has extensive re-entrant connections between regions, implying that perception does not exclusively conform to a hierarchy of analysis (Bullier, 2001; Zeki, 1993).”

“…nature of human vision whereby different hierarchical levels interact in both feedforward and feedback fashion (Lamme and Roelfsema, 2000; Bullier, 2001), from the earliest and most elementary stage (feature extraction; Morgan, 2011) to the fur-thest and most advanced one (image…”

“What is the reason for the existence of a motionbased feedback mechanism (Bullier, 2001; PascualLeone & Walsh, 2001)? It is possible that it could be a verification mechanism, testing whether motion calculations are correct by checking that the spatial displacement of an object is consistent with computed motion.”

“Conscious visual recognition of the prime, however, only occurs when recurrent feedback activity from higher visual areas re-enters V1 in the shape of a feed backward sweep (Bullier, 2001; Fenske et al., 2006; Lamme and Roelfsema, 2000; Laycock et al., 2007; Tong, 2003).”

“…that, in order for wareness to arise, different cortical areas must not only interct with one another, but must interact in a reciprocal maner (Bullier, 2001; Dehaene, Sergent et al., 2003; Hochstein Ahissar, 2002; Lamme & Roelfsema, 2000; Pollen, 2003; ononi, Edelman et al., 1998; Varela,…”

“Third, on the basis of theoretical and empirical considerations, re-entry is regarded as necessary for conscious vision [92–94].”

“While other theoretical frameworks have dealt with attention (Olshausen, Anderson, & Van Essen, 1993; Treisman, 1996), and top-down processing in vision (Ahissar & Hochstein, 2004; Bullier, 2001; Di Lollo, 2010; Lamme & Roelfsema, 2000), few have proposed an inherent link between top-down processing and attention (Dec…”

“For instance, face-selective cells in the monkey inferotemporal (IT) cortex (e.g. Desimone, Albright, Gross, & Bruce, 1984; Gross & Sergent, 1992; Perrett, Rolls, & Caan, 1982; Rolls, 1992) start discharging at about 80–130ms after stimulus onset (Bullier, 2001; Oram & Perrett, 1992).”

“390 Feedback projections are quite ubiquitous in the central nervous system [28], and 391 their role in regulating neuronal network activity [40,41], brain activity 392 oscillations [42–44], and high level brain functions such as working memory [45], 393 vision [46,47], attention [48,49], and consciousness [50–52] is…”

“These results suggest that feedback amplification could be a fundamental feature of visual identification and/or consciousness (Crouzet & Cauchoix, 2011; Dehaene & Changeux, 2011; Lamme, 2006; Bullier, 2001a, 2001b).”

“The second category includes theories according to which it is recurrent neural activity within sensory areas that is necessary and sufficient for visually conscious states (Edelman and Tonini 2000; Bullier 2001; Pascual-Leone andWalsh 2001).”

“Recurrent feedback is thought to be critical for conscious experience (Bullier, 2001; V. A. Lamme & Roelfsema, 2000; Pascual-Leone & Walsh, 2001), though importantly, recent evidence indicates that long-range feedback connections from prefrontal cortex, rather than local feedback loops in visual…”

“direct modulation of visual awareness through TMS disruption of these late signals (Camprodon et al., 2010; Bullier, 2001).”

“It is also well known that there are massive feedback connections between IT and lower level retinotopic visual areas, which play much more than a passive feed-forward role in processing information (Bullier 2001, Kveraga et al. 2007).”

“Feedback projections also play an essential role in visual awareness (Bullier, 2001; Ro, Breitmeyer, Burton, Singhal, & Lane, 2003). Pascual-Leone and Walsh (2001) reported that whereas participants who received transcranial magnetic stimulation (TMS) at V1 before receiving it at V5 reported seeing moving phosphenes (…”

“Lesion studies (Lamme et al. 1998; Bullier 2001) corroborated by demonstrations on conducting speed of lateral connections (Bringuier et al.”

“MEG-fMRI fusion results also demonstrate strong agreement with independently collected spatiotemporal results [15,16,67–70] The goal of our ROI analysis was to broadly test the ventral visual cortex, abutting regions, and classical memory regions that may be implicated in visual perception.”

“Their role appears to be one of fine tuning a response by a reinforcing the ongoing activity using response facilitation [39–41].”

“It has, however, been argued that activity in V1 is crucial for visual consciousness (Pascual-Leone and Walsh, 2001; Tong, 2003), on the basis of experiments in which visual experience appeared to require the establishing of feedback loops between V1 and a downstream brain area (Bullier, 2001; Pascual-Leone and Walsh,…”

“Error bars denote S.E.M. from MT to V1 is also well established (Maunsell and van Essen, 1983; Shipp and Zeki, 1989; Bullier, 2001; Pascual-Leone and Walsh, 2001; Muckli et al., 2005; Silvanto et al., 2005; Sillito et al., 2006) with inhibitory feedback connections outnumbering excitatory feedback…”

“…accepted that feedback or re-entrant processing from anterior to poster visual regions is critically involved in rendering stimulus representations consciously accessible (Bullier, 2001; Di Lollo, 2010; Di Lollo, Enns, & Rensink, 2000; Dux, Visser, Goodhew, & Lipp, 2010; Lamme & Roelfsema, 2000).”

“…& de Lange, 2012; Manita et al., 2015) and plays a crucial role in supporting perception especially when sensory input is weak or ambiguous (e.g., Bullier, 2001; Chen et al., 2014; Grassi, Zaretskaya, & Bartels, 2017; Hupé et al., 1998; Schwiedrzik & Freiwald, 2017), with even very long-range…”

“This pathway (i.e., geniculostriate) is also thought to support awareness of visual motion through recurrent feedback to V1 (Bullier, 2001; Lamme, 2001; Pascual-Leone & Walsh, 2001).”

“…recognition, whereby processes in higher-order regions influence those in sensory-driven regions from the earliest stages, prior to recognition, and before a fine-grained meaningful representation has been achieved (Lamme and Roelfsema, 2000; Bullier, 2001; Bar et al., 2006; Clarke et al., 2011).”

“…between different cortical areas, the speed of electric signal propagation along these connections, and the latency of visual response all suggest that feedback connections may contribute significantly to receptive field properties (Bullier, 2001; Angelucci et al., 2002; Borra & Rockland, 2011).”

“This is consistent with models suggesting that recurrent processing in early visual areas is necessary for visual awareness, perhaps with early visual areas acting as active ‘‘black-boards,’’ integrating computation outputs from higher-order areas (Bullier, 2001).”

“Because rotation is thought to be processed in a higher stage, the authors suggested that interactions between lower and higher areas through abundant recurrent inputs from area MT to V1 and V2 (Bullier, 2001; Shipp & Zeki, 1989a, 1989b) are involved in the MIPS.”

“The exuberance of the feedback connections between different cortical areas, the speed of electric signal propagation along these connections, and the latency of visual response all suggest that feedback connections could affect the functional performance of neurons beyond a “modulatory” role (Angelucci et al., 2002;…”

“Recent empirical and theoretical work (Bullier, 2001; Hochstein & Ahissar, 2002; Lamme, 2006; Lamme & Roelfsema, 2000; Supèr, Spekreijse, & Lamme, 2001), supports the strong hypothesis that cortical feedforward and reentrant feedback activities provide a”

“…to be a very generic one that operates across different areas of the cortical mantle, allowing prior knowledge (and likely other signals as well) to influence everything from visual perception [Bullier, 2001] to memory retrieval [Tomita et al., 1999] and sensorimotor coordination [Xu et al., 2012].”

“The interactive theory of visual consciousness states that the visual signals do not simply travel to the higher areas but that the higher areas send feedback signals back down to lower visual areas, especially to BA17 [33,34].”

“In a series of articles, Jean Bullier (Nowak and Bullier 1997; Bullier 2001a, b) has made the case that the magnocellular stream, as well as areas in parietal and frontal cortex, including the dorsal stream, constitutes what he calls the “fast brain” system.”

“The existence of such processes has been hypothesised within the module of low level vision: according to Bullier (Bullier 2001a, b, cfr. also sect.”

“, 2000; Lamme and Roelfsema, 2000; Bullier, 2001; Hochstein and Ahissar, 2002; Hamker, 2003). As far as the visual system is concerned, such signals emanate from the parietal cortex. Saalmann et al. (2007) studied how parietal output influences early sensory areas in macaques performing a visual matching task.”

“, MT) and the results of the computation can be fedback to V1 in time for the arrival of parvo wave of activity (Bullier, 2001). Also, recent studies have indicated a direct projection from LGN to MT bypassing V1 (Sincich, Park, Wohlgemuth, & Horton, 2004). Parvo-related cortical sites are more suitable candidates for…”

“, Bullier , 2001 ) , or at an intermediate grain via sequences of fixations to foveate on critical visual information in models of scene analysis that incor - porate an anisotropic retina ( e . g .”

“Recurrent interactions between feedforward and feedback activity also occur on the timescale of a few 10s of ms (Bullier, 2001; Hupe et al., 2001; Pascual-Leone & Walsh, 2001).”