Representation of Accumulating Evidence for a Decision in Two Parietal Areas

“The reported latencies are the times at which the ROC index significantly departed from 0.5 for at least 50 ms ( p 0.05; Hanley and McNeil, 1982).”

“Experimental control and stimulus presentation were achieved with either REX (Hays et al., 1982) in combination with the Psychophysics toolbox (Brainard, 1997) or with EXPO (developed by Peter Lennie, currently maintained by Rod Dotson, Center for Neural Science at New York University, New York,…”

“This is not the type of parallel processing that is often associated with neural networks (Rumelhart and McClelland, 1986) or computer systems but is instead a direct representation (Barlow, 1995) of a decision variable in the firing rates of neurons.”

“Such an accumulation of noisy evidence has been likened to a random walk or diffusion process (Ratcliff, 1978; Gold and Shadlen, 2002).”

“…occurs in circuits associated with provisional behavioral responses to stim- uli (Schall, 2001; Romo et al., 2004; Rorie and Newsome, 2005; Gold and Shadlen, 2007; Lemus et al., 2007; Andersen and Cui, 2009; Cisek and Kalaska, 2010; Hernández et al., 2010; Westendorff et al., 2010),…”

“We estimated the rate of this rise or decline by fitting lines to the response averages in the 150 ms epoch from the earliest point that these trends appear to emerge (see Materials and Methods).”

“…saccadic eye movements (Thier and Andersen, 1998), MIP neurons signal the spatial location of objects that are potential targets of reach movements (Mountcastle et al., 1975; Johnson et al., 1996; Snyder et al., 1997; Batista et al., 1999; Eskandar and Assad, 1999), as well as the outcome of…”

“We recorded from single neurons in areas LIP and MIP of two rhesus monkeys that were trained to judge the direction of motion of a dynamic random-dot display (Britten et al., 1992).”

“We also fit a bounded drift-diffusion model (Ratcliff, 1978; Gold and Shadlen, 2002; Bogacz et al., 2006) to account for the variation in choice accuracy as a function of the duration, strength, and direction of random-dot motion (Fig.”

“7, insets), consistent with the hypothesis that the firing rates represent the accumulated difference in motion evidence from opposing pools of motion-sensing neurons, such as those in middle temporal area MT (Shadlen and Newsome, 1996, 2001; Mazurek et al., 2003; Huk and Shadlen, 2005).”

“…of motion in a dynamic random-dot display, neural correlates of evidence accumulation (Shadlen and Newsome, 1996; Huk and Shadlen, 2005), value (Platt and Glimcher, 1999; Rorie et al., 2010), probability (Yang and Shadlen, 2007), and confidence (Kiani and Shadlen, 2009) have been identified in…”

“, 2004) and also as reflecting covert eye movements that might occur were the monkeys not required to hold fixation away from the reach target (Snyder et al., 1997, 1998; Colby and Goldberg, 1999).”

“…in LIP and other oculomotor areas suggests that the motor system is not recruited once a decision is made but instead receives a continuous flow of partial information—an evolving decision variable (Gold and Shadlen, 2007; McKinstry et al., 2008; Cisek and Kalaska, 2010; Selen et al., 2012).”

“…a sign of allocation of spatial attention (Robinson et al., 1978; Bushnell et al., 1981; Wardak et al., 2004) and also as reflecting covert eye movements that might occur were the monkeys not required to hold fixation away from the reach target (Snyder et al., 1997, 1998; Colby and Goldberg, 1999).”

“, 2010), probability (Yang and Shadlen, 2007), and confidence (Kiani and Shadlen, 2009) have been identified in the firing rates of neurons in the parietal and prefrontal association cortex and in subcortical structures associated with the preparation of eye movements (Horwitz and Newsome, 1999).”

“The random-dot motion task is useful for studying this process because (1) its solution requires integration of evidence across space and time and (2) a neural representation of the momentary evidence has been established in areas MT and MST (Salzman et al., 1990; Celebrini and Newsome, 1994; Ditterich et al., 2003).”

“Together, these analyses allow us to appreciate that the firing rate functions plotted in Figure 7 are the means of diffusion paths, as predicted by the drift-diffusion model (Link, 1975; Ratcliff, 1978; Gold and Shadlen, 2001).”

“The recruitment of saccade-related neurons during reach movements has been interpreted in the past as a sign of allocation of spatial attention (Robinson et al., 1978; Bushnell et al., 1981; Wardak et al., 2004) and also as reflecting covert eye movements that might occur were the monkeys not required to hold fixation…”

“The recruitment of saccade-related neurons during reach movements has been interpreted in the past as a sign of allocation of spatial attention (Robinson et al., 1978; Bushnell et al., 1981; Wardak et al., 2004) and also as reflecting covert eye movements that might occur were the monkeys not required to hold fixation…”

“…provisional behavioral responses to stim- uli (Schall, 2001; Romo et al., 2004; Rorie and Newsome, 2005; Gold and Shadlen, 2007; Lemus et al., 2007; Andersen and Cui, 2009; Cisek and Kalaska, 2010; Hernández et al., 2010; Westendorff et al., 2010), which has been termed an intentional—as…”

“7, insets), consistent with the hypothesis that the firing rates represent the accumulated difference in motion evidence from opposing pools of motion-sensing neurons, such as those in middle temporal area MT (Shadlen and Newsome, 1996, 2001; Mazurek et al., 2003; Huk and Shadlen, 2005).”

“…the spatial location of objects that are potential targets of reach movements (Mountcastle et al., 1975; Johnson et al., 1996; Snyder et al., 1997; Batista et al., 1999; Eskandar and Assad, 1999), as well as the outcome of decisions to direct the arm in a particular direction (Snyder et al.,…”

“…and Andersen, 1998), MIP neurons signal the spatial location of objects that are potential targets of reach movements (Mountcastle et al., 1975; Johnson et al., 1996; Snyder et al., 1997; Batista et al., 1999; Eskandar and Assad, 1999), as well as the outcome of decisions to direct the arm in…”

“…and not about the plan of action used to communicate the choice, yet our decisions are governed by an evidence accumulation process similar to the one studied in monkeys (Smith and Ratcliff, 2004; Palmer et al., 2005; Philiastides et al., 2006; Green et al., 2012; O’Connell et al., 2012).”

“…of these fluctuations on the monkeys’ choices, we extracted the motion energy profile (Adelson and Bergen, 1985; Neri, 2004; Kiani et al., 2008; Resulaj et al., 2009) as a function of time from the dis- play of each trial, applying a sign convention such that positive motion energy represents…”

“7, insets), consistent with the hypothesis that the firing rates represent the accumulated difference in motion evidence from opposing pools of motion-sensing neurons, such as those in middle temporal area MT (Shadlen and Newsome, 1996, 2001; Mazurek et al., 2003; Huk and Shadlen, 2005).”

“…of evidence accumulation (Shadlen and Newsome, 1996; Huk and Shadlen, 2005), value (Platt and Glimcher, 1999; Rorie et al., 2010), probability (Yang and Shadlen, 2007), and confidence (Kiani and Shadlen, 2009) have been identified in the firing rates of neurons in the parietal and prefrontal…”

“In particular, LIP is known to represent the accumulated evidence, combined with other factors that affect the decision, such as the previous probability, value, and costs associated with the alternatives (Seo et al., 2009; Rorie et al., 2010; Hanks et al., 2011; Drugowitsch et al., 2012).”

“7, insets), consistent with the hypothesis that the firing rates represent the accumulated difference in motion evidence from opposing pools of motion-sensing neurons, such as those in middle temporal area MT (Shadlen and Newsome, 1996, 2001; Mazurek et al., 2003; Huk and Shadlen, 2005).”

“…areas supports the idea that analysis of sensory information occurs in circuits associated with provisional behavioral responses to stim- uli (Schall, 2001; Romo et al., 2004; Rorie and Newsome, 2005; Gold and Shadlen, 2007; Lemus et al., 2007; Andersen and Cui, 2009; Cisek and Kalaska,…”

“To quantify the influence of these fluctuations on the monkeys’ choices, we extracted the motion energy profile (Adelson and Bergen, 1985; Neri, 2004; Kiani et al., 2008; Resulaj et al., 2009) as a function of time from the dis- play of each trial, applying a sign convention such that positive…”

“, 1999; Eskandar and Assad, 1999), as well as the outcome of decisions to direct the arm in a particular direction (Snyder et al., 1997; Eskandar and Assad, 1999; Scherberger and Andersen, 2007; Pesaran et al., 2008).”

“…and not about the plan of action used to communicate the choice, yet our decisions are governed by an evidence accumulation process similar to the one studied in monkeys (Smith and Ratcliff, 2004; Palmer et al., 2005; Philiastides et al., 2006; Green et al., 2012; O’Connell et al., 2012).”

“In particular, LIP is known to represent the accumulated evidence, combined with other factors that affect the decision, such as the previous probability, value, and costs associated with the alternatives (Seo et al., 2009; Rorie et al., 2010; Hanks et al., 2011; Drugowitsch et al., 2012).”

“We then combined the residuals and their associated means using Equation 6 from the study by Churchland et al. (2011) to estimate the VarCE, S Ni 2 , in the six time bins under the four conditions (area by effector), given .”

“…supports the idea that analysis of sensory information occurs in circuits associated with provisional behavioral responses to stim- uli (Schall, 2001; Romo et al., 2004; Rorie and Newsome, 2005; Gold and Shadlen, 2007; Lemus et al., 2007; Andersen and Cui, 2009; Cisek and Kalaska, 2010; Hernández…”

“Moreover, the accumulating sensory evidence that will ultimately support one or the other choice—an evolving decision variable— has been shown to flow continuously to motor structures in the human brain much as it does in monkeys (McKinstry et al., 2008; Selen et al., 2012; Ding and Gold, 2013).”

“…its decision with an eye movement, a neural representation of the accumulated evidence has been demonstrated in area LIP, the frontal eye fields, the superior colliculus, and the dorsolateral prefrontal cortex (Horwitz and Newsome, 1999; Gold and Shadlen, 2000, 2007; Ding and Gold, 2012).”

“…its decision with an eye movement, a neural representation of the accumulated evidence has been demonstrated in area LIP, the frontal eye fields, the superior colliculus, and the dorsolateral prefrontal cortex (Horwitz and Newsome, 1999; Gold and Shadlen, 2000, 2007; Ding and Gold, 2012).”

“The random-dot motion task is useful for studying this process because (1) its solution requires integration of evidence across space and time and (2) a neural representation of the momentary evidence has been established in areas MT and MST (Salzman et al., 1990; Celebrini and Newsome, 1994; Ditterich et al., 2003).”

“The random-dot motion task is useful for studying this process because (1) its solution requires integration of evidence across space and time and (2) a neural representation of the momentary evidence has been established in areas MT and MST (Salzman et al., 1990; Celebrini and Newsome, 1994; Ditterich et al., 2003).”

“Just as LIP neurons signal the location of objects that are potential objects of saccadic eye movements (Thier and Andersen, 1998), MIP neurons signal the spatial location of objects that are potential targets of reach movements (Mountcastle et al.”

“Moreover, the accumulating sensory evidence that will ultimately support one or the other choice—an evolving decision variable— has been shown to flow continuously to motor structures in the human brain much as it does in monkeys (McKinstry et al., 2008; Selen et al., 2012; Ding and Gold, 2013).”

“…of objects that are potential targets of reach movements (Mountcastle et al., 1975; Johnson et al., 1996; Snyder et al., 1997; Batista et al., 1999; Eskandar and Assad, 1999), as well as the outcome of decisions to direct the arm in a particular direction (Snyder et al., 1997; Eskandar and Assad,…”

“Moreover, the accumulating sensory evidence that will ultimately support one or the other choice—an evolving decision variable— has been shown to flow continuously to motor structures in the human brain much as it does in monkeys (McKinstry et al., 2008; Selen et al., 2012; Ding and Gold, 2013).”

“In monkeys trained to discriminate the direction of motion in a dynamic random-dot display, neural correlates of evidence accumulation (Shadlen and Newsome, 1996; Huk and Shadlen, 2005), value (Platt and Glimcher, 1999; Rorie et al., 2010), probability (Yang and Shadlen, 2007), and confidence (Kiani and Shadlen, 2009)…”

“…during reach movements has been interpreted in the past as a sign of allocation of spatial attention (Robinson et al., 1978; Bushnell et al., 1981; Wardak et al., 2004) and also as reflecting covert eye movements that might occur were the monkeys not required to hold fixation away from the reach…”

“…a sign of allocation of spatial attention (Robinson et al., 1978; Bushnell et al., 1981; Wardak et al., 2004) and also as reflecting covert eye movements that might occur were the monkeys not required to hold fixation away from the reach target (Snyder et al., 1997, 1998; Colby and Goldberg, 1999).”

“, 1999; Eskandar and Assad, 1999), as well as the outcome of decisions to direct the arm in a particular direction (Snyder et al., 1997; Eskandar and Assad, 1999; Scherberger and Andersen, 2007; Pesaran et al., 2008).”

“It is also important to note that our experiments were not designed to test effector specificity, and our results might be specific to LIPv and anterior MIP (Liu et al., 2010).”

“In particular, LIP is known to represent the accumulated evidence, combined with other factors that affect the decision, such as the previous probability, value, and costs associated with the alternatives (Seo et al., 2009; Rorie et al., 2010; Hanks et al., 2011; Drugowitsch et al., 2012).”

“The model, which assumes perfect integration of evidence to a threshold or bound, has been shown to account for the rate of improvement in accuracy as a function of both variables (Kiani et al., 2008; Tsetsos et al., 2012).”

“Indeed, careful reading of studies that support motor specialization (Snyder et al., 1997; Cui and Andersen, 2011) attests to only a relative preference for modality, as these investigators have emphasized (Andersen and Cui, 2009).”

“The absence of a visual response to the onset of visual targets is consistent with the anterior location of our recordings in MIP, possibly at the border of MIP/5v (Hwang et al., 2012).”

“…analysis of sensory information occurs in circuits associated with provisional behavioral responses to stim- uli (Schall, 2001; Romo et al., 2004; Rorie and Newsome, 2005; Gold and Shadlen, 2007; Lemus et al., 2007; Andersen and Cui, 2009; Cisek and Kalaska, 2010; Hernández et al., 2010;…”

“…2004; Rorie and Newsome, 2005; Gold and Shadlen, 2007; Lemus et al., 2007; Andersen and Cui, 2009; Cisek and Kalaska, 2010; Hernández et al., 2010; Westendorff et al., 2010), which has been termed an intentional—as opposed to representational—framework for information processing (Shadlen et…”

“…associated with provisional behavioral responses to stim- uli (Schall, 2001; Romo et al., 2004; Rorie and Newsome, 2005; Gold and Shadlen, 2007; Lemus et al., 2007; Andersen and Cui, 2009; Cisek and Kalaska, 2010; Hernández et al., 2010; Westendorff et al., 2010), which has been termed an…”

“To quantify the influence of these fluctuations on the monkeys’ choices, we extracted the motion energy profile (Adelson and Bergen, 1985; Neri, 2004; Kiani et al., 2008; Resulaj et al., 2009) as a function of time from the dis- play of each trial, applying a sign convention such that positive…”

“…and not about the plan of action used to communicate the choice, yet our decisions are governed by an evidence accumulation process similar to the one studied in monkeys (Smith and Ratcliff, 2004; Palmer et al., 2005; Philiastides et al., 2006; Green et al., 2012; O’Connell et al., 2012).”

“…formally identical to evidence accumulation described by drift diffusion or race-to-bound models (Solway & Botvinick, 2012; Zhang & Maloney, 2012; de Lafuente et al., 2015; Kira et al., 2015) and nicely recapitulates the emergence of a choice as evaluation of options proceeds (Hunt et al., 2012).”

“This formulation also has some construct validity in relation to theoretical proposals and empirical work on evidence accumulation (de Lafuente, Jazayeri, & Shadlen, 2015; Kira, Yang, & Shadlen, 2015) and the neuronal encoding of probabilities (Deneve, 2008).”

“Movements with fine temporal structure, cognitive functions such as deliberation and integration (de Lafuente et al., 2015; Hanks et al., 2015;Merchant and Georgopoulos, 2006; Roitman and Shadlen, 2002; Shadlen and Gold, 2004; Thura and Cisek, 2014), and behaviors that depend on knowledge of…”

“, [74]) In many of the decisions subjects face in their daily life, LIP, in fact, may not have a role at all.”