Common Rules Guide Comparisons of Speed and Direction of Motion in the Dorsolateral Prefrontal Cortex

Abstract

When a monkey needs to decide whether motion direction of one stimulus is the same or different as that of another held in working memory, neurons in dorsolateral prefrontal cortex (DLPFC) faithfully represent the motion directions being evaluated and contribute to their comparison. Here, we examined whether DLPFC neurons are more generally involved in other types of sensory comparisons. Such involvement would support the existence of generalized sensory comparison mechanisms within DLPFC, shedding light on top-down influences this region is likely to provide to the upstream sensory neurons during comparison tasks. We recorded activity of individual neurons in the DLPFC while monkeys performed a memory-guided decision task in which the important dimension was the speed of two sequentially presented moving random-dot stimuli. We found that many neurons, both narrow-spiking putative local interneurons and broad-spiking putative pyramidal output cells, were speed-selective, with tuning reminiscent of that observed in the motion processing middle temporal (MT) cortical area. Throughout the delay, broad-spiking neurons were more active, showing anticipatory rate modulation and transient periods of speed selectivity. During the comparison stimulus, responses of both cell types were modulated by the speed of the first stimulus, and their activity was highly predictive of the animals’ behavioral report. These results are similar to those found for comparisons of motion direction, suggesting the existence of generalized neural mechanisms in the DLPFC subserving the comparison of sensory signals.

Interaction between Spatial and Feature Attention in Posterior Parietal Cortex

“…Although the respective timing of attentional modulations are consistent with LIP driving attentional modulations in MT, these correlations do not provide direct evidence for a causal relationship. An alternative, and perhaps likely possibility is that attentional modulations in visual and parietal cortices are driven by top-down modulation from FEF (Astrand et al, 2015; Gregoriou et al, 2009; Ibos et al, 2013; Moore and Armstrong, 2003; Wardak et al, 2006) and PFC (Bichot et al, 2015; Hussar and Pasternak, 2013; Lennert and Martinez-Trujillo, 2011, 2013; Tremblay et al, 2015). For example, both electrical and pharmacological manipulation of FEF have been shown to produce attention-like modulation of activity in V4 (Armstrong and Moore, 2007; Noudoost and Moore, 2011; Schafer and Moore, 2011).…”

“…SBA or FBA have both been shown to enhance encoding of task relevant locations or features throughout the visual cortical hierarchy (Cohen and Maunsell, 2011; Connor et al, 1997; Ipata et al, 2012; Martinez-Trujillo and Treue, 2004; Maunsell and Treue, 2006) as well as higher order areas such as the Lateral Intraparietal (LIP) area (Bisley and Goldberg, 2010; Herrington and Assad, 2009; Ibos and Freedman, 2014), frontal-eye field (FEF) (Armstrong et al, 2009; Ibos et al, 2013; Zhou and Desimone, 2011) and prefrontal cortex (PFC) (Bichot et al, 2015; Hussar and Pasternak, 2013; Lennert and Martinez-Trujillo, 2011, 2013; Tremblay et al, 2015). Moreover, the impact of SBA and FBA on the response of visual cortical neurons suggests that both types of attention modulate neuronal processing in similar ways (Cohen and Maunsell, 2009, 2011; Hayden and Gallant, 2009; Leonard et al, 2015).…”

Visuomotor Functions in the Frontal Lobe

“…Tsujimoto & Postle 2012, Sreenivasan et al 2014. Consistent with the visual field map, the dorsal PFC tends to represent object location more than identity, whereas the ventral PFC tends to represent stimulus features or object identity; however, overlapping and mixed representations are common (Zaksas & Pasternak 2006, Meyer et al 2011, Hussar & Pasternak 2013, Funahashi 2015, Kadohisa et al 2015cf. Lara & Wallis 2014).…”

Single-cell coding of sensory, spatial and numerical magnitudes in primate prefrontal, premotor and cingulate motor cortices

“…The tuning properties of visual motion-selective PFC neurons mirror those observed in the motion processing middle temporal (MT) cortical area. Additionally, they observed that the majority of tasksensitive neurons were selective for both speed and motion direction, and suggested a generalized neural mechanism for the comparison of sensory signals in PFC (Hussar and Pasternak 2013). Sensory attributes of mnemonic representations were also reported by Constantinidis et al (Constantinidis et al 2001) who found that PFC activity reflected graded variations in the luminance of a to-be-remembered stimulus.…”