Biology subjects

Masis, J. A.

Publications and source records attributed to Masis, J. A..

3 recordsLinked to original sources

bioRxiv2023

Neural correlates of visual object recognition in rats

Invariant object recognition--the ability to recognize objects across size, rotation, or context--is fundamental for making sense of a dynamic visual world. Although initially believed to be unique to primates due to its complexity, emerging evidence suggests rodents, too, can recognize objects across a range of identity-preserving transformations. Here, we describe a comprehensive pipeline for investigating visual behavior in rats, from high-throughput training to cellular resolution imaging in awake, head-fixed animals. Using this suite of tools, we demonstrate that rats excel in visual object recognition and explore potential neural pathways which may support this capacity. We leverage our optical approach to systematically profile multiple visual areas with responses to a range of stimulus types recorded in the same neurons. Primary and higher-order areas of rat visual cortex exhibit a hierarchical organization consistent with a role in visual object recognition. However, marked deviations from the functional organization of primate visual cortex suggest species-specific differences in the neural circuits underlying visual object recognition. This work reinforces the notion that rats possess sophisticated visual abilities and offers the technical foundation for their use as a powerful model to link neuronal responses to perception and behavior.

neuroscience↗

bioRxiv2020

Rats strategically manage learning during perceptual decision making

Balancing the speed and accuracy of decisions is crucial for survival, but how organisms manage this trade-off during learning is largely unknown. Here, we track this trade-off during perceptual learning in rats and simulated agents. At the start of learning, rats chose long reaction times that did not optimize instantaneous reward rate, but by the end of learning chose near-optimal reaction times. To understand this behavior, we analyzed learning dynamics in a recurrent neural network model of the task. The model reveals a fundamental trade-off between instantaneous reward rate and perceptual learning speed, putting the goals of learning quickly and accruing immediate reward in tension. We find that the rats strategy of long initial responses can dramatically expedite learning, yielding higher total reward over task engagement. Our results demonstrate that prioritizing learning can be advantageous from a total reward perspective, and suggest that rats engage in cognitive control of learning.

neuroscience↗

bioRxiv2020

Encoding of 3D Head Orienting Movements in Primary Visual Cortex

Animals actively sample from the sensory world by generating complex patterns of movement that evolve in three dimensions. At least some of these movements have been shown to influence neural codes in sensory areas. For example, in primary visual cortex (V1), locomotion-related neural activity influences sensory gain, encodes running speed, and predicts the direction of visual flow. As most experiments exploring movement-related modulation of V1 have been performed in head-fixed animals, it remains unclear whether or how the naturalistic movements used to interact with sensory stimuli- like head orienting-influence visual processing. Here we show that 3D head orienting movements modulate V1 neuronal activity in a direction-specific manner that also depends on the presence or absence of light. We identify two largely independent populations of movement-direction-tuned neurons that support this modulation, one of which is direction-tuned in the dark and the other in the light. Finally, we demonstrate that V1 gains access to a motor efference copy related to orientation from secondary motor cortex, which has been shown to control head orienting movements. These results suggest a mechanism through which sensory signals generated by purposeful movement can be distinguished from those arising in the outside world, and reveal a pervasive role of 3D movement in shaping sensory cortical dynamics.

neuroscience↗