Activity in LIP, But not V4, Matches Performance When Attention is Spread

Abstract

The enhancement of neuronal responses in many visual areas while animals perform spatial attention tasks has widely been thought to be the neural correlate of visual attention, but it is unclear whether the presence or absence of this modulation contributes to our striking inability to notice changes in change blindness examples. We asked whether neuronal responses in visual area V4 and the lateral intraparietal area (LIP) in posterior parietal cortex could explain the limited ability of subjects to attend multiple items in a display. We trained animals to perform a change detection task in which they had to compare 2 arrays of stimuli separated briefly in time and found that each animal's performance decreased as function of set-size. Neuronal discriminability in V4 was consistent across set-sizes, but decreased for higher set-sizes in LIP. The introduction of a reward bias produced attentional enhancement in V4, but this could not explain the vast improvement in performance, whereas the enhancement in LIP responses could. We suggest that behavioral set-size effects and the marked improvement in performance with focused attention may not be related to response enhancement in V4 but, instead, may occur in or on the way to LIP.

Neuronal Responses in Posterior Parietal Cortex during Learning of Implied Serial Order

“…The weighted average was biased roughly 70:30 in favor of the stimulus inside the receptive field. These results are in general accord with previous work showing that LIP neurons can be influenced by stimuli outside the receptive field (Falkner et al, 2010;Arcizet et al, 2018).…”

“…During each trial, one stimulus appeared either inside the receptive field of the neuron (T in ) or at a location diametrically opposite to the receptive field (T out ). Neuronal responses on these "single target" trials were compared to later "decision" trials with a target (T in ) and distractor (D in ) to determine the effect of the stimulus outside the receptive field, given prior reports of surround suppression in LIP (Falkner et al, 2010;Arcizet et al, 2018). Responses (defined as spike counts within a time window of 50 to 150 msec after stimulus onset) to a single target in the receptive field (T in ) were compared to responses with a target in the receptive field and distractor at the opposite location (T in + D out ).…”

Having More Choices Changes How Human Observers Weight Stable Sensory Evidence

“…In the present study, we used the contrast discrimination task for several reasons. First, contrast-change detection/discrimination is a good model task to examine perceptual decision-making processes because changes in contrast impact the efficiency of perceptual decisions about the orientation, color, motion, form, identity, and semantic properties of visual stimuli (Albrecht and Hamilton, 1982;Hawken et al, 1994;Alitto and Usrey, 2004;Murray and He, 2006;Herrmann et al, 2010Herrmann et al, , 2012Purcell et al, 2010;Lui et al, 2013;Khayat and Martinez-Trujillo, 2015;Long et al, 2015;Khastkhodaei et al, 2016;Störmer and Alvarez, 2016;Wang and Movshon, 2016;Bloem and Ling, 2017;Hermes et al, 2017;Kay and Yeatman, 2017). Second, manipulating contrast enables precise control over task difficulty and other cognitive factors, such as spatial attention (Ross et al, 1993;Boynton et al, 1999;Gorea and Sagi, 2001;Huang and Dobkins, 2005;Pestilli et al, 2011;Hara and Gardner, 2014;Itthipuripat et al, 2014a.…”

Attentional Changes in Either Criterion or Sensitivity Are Associated with Robust Modulations in Lateral Prefrontal Cortex

“…However, the attention-related improvement in hit rate can be partitioned into two independent components using signal detection theory: either changes in the subject’s criterion ( c ) or changes in the subject’s sensitivity ( d ′) (Figure 1A; Bashinski and Bacharach, 1980; Müller and Findlay, 1987; Downing, 1988; Hawkins et al, 1990; Müller and Humphreys, 1991; Wyart et al, 2012; Luo and Maunsell, 2015; Sridharan et al, 2017; Arcizet et al, 2017). A subject’s criterion corresponds to how readily the subject reports a target or withholds from such a report.…”