Frontal cortex learns to add evidence across modalities

Abstract

To interpret the world and make accurate perceptual decisions, the brain must combine information across sensory modalities. For instance, it must combine vision and hearing to localize objects based on their image and sound. Probability theory suggests that evidence from multiple independent cues should be combined additively, but it is unclear whether mice and other mammals do this, and the cortical substrates of multisensory integration are uncertain. Here we show that to localize a stimulus mice combine auditory and visual spatial cues additively, a computation supported by unisensory processing in auditory and visual cortex and additive multisensory integration in frontal cortex. We developed an audiovisual localization task where mice turn a wheel to indicate the joint position of an image and a sound. Scanning optogenetic inactivation of dorsal cortex showed that auditory and visual areas contribute unisensory information, whereas frontal cortex (secondary motor area, MOs) contributes multisensory information to the decision of the mouse. Neuropixels recordings of >10,000 neurons indicated that neural activity in MOs reflects an additive combination of visual and auditory signals. An accumulator model applied to the sensory representations of MOs neurons reproduced behaviourally observed choices and reaction times. This suggests that MOs integrates information from multiple sensory cortices, providing a signal that is then transformed into a binary decision by a downstream accumulator.

Pyramidal cell types drive functionally distinct cortical activity patterns during decision-making

“…Frontal inactivation strongly impaired animal behavior during the stimulus and delay periods, suggesting an important role for the translation of sensory inputs into behavior 21,69,[72][73][74] . Impairments were largely similar across frontal PyN types, which appear to be equally required for choice formation and retention.…”

Hearing, touching, and multisensory integration during mate choice

“…Thinking of cognition, and in particular, decision making, the prefrontal cortex (PFC) might be the most obvious player coming into the equation. Various recent studies investigated PFC activity during active decision making in the mouse (Bicks et al, 2015;Vertechi et al, 2020;Posner et al, 2022) and rat (Kurikawa et al, 2018;Verharen et al, 2020) describing multi-modal processing capacities (Bizley et al, 2016; 10.3389/fncir.2022.943888 Shadi et al, 2020;Coen et al, 2021;Zheng et al, 2021) and implications during social cognition (Yizhar et al, 2011;Felix-Ortiz et al, 2016;Murugan et al, 2017;Levy et al, 2019;Mague et al, 2020). More particular, multiple studies point to a prominent role of PFC during opposite-sex choice and social approach behavior (Nakajima et al, 2014;Kim et al, 2015;Lee et al, 2016;Jennings et al, 2019;Levy et al, 2019;Kingsbury et al, 2020).…”

Mouse frontal cortex nonlinearly encodes sensory, choice and outcome signals

“…The secondary motor area (MOs) in mice is a key frontal cortical structure for making decisions based on sensory evidence and reward (Barthas and Kwan, 2017). Inactivation of MOs affects performance in multiple tasks, involving multiple sensory modalities and behavioral outputs (Erlich et al, 2011(Erlich et al, , 2015Sul et al, 2011;Guo et al, 2014;Hanks et al, 2015;Goard et al, 2016;Coen et al, 2021;Kondo and Matsuzaki, 2021;Zatka-Haas et al, 2021;Atilgan et al, 2022). Recordings in MOs have shown diverse correlates of task variables including sensory inputs, rewards, and choices.…”