Biology subjects

Gutierrez, R.

Publications and source records attributed to Gutierrez, R..

21 records · Page 2Linked to original sources

bioRxiv2021

Interoceptive perception of optogenetic brain stimulation

How do animals experience brain manipulations? Optogenetics has allowed us to manipulate selectively and interrogate neural circuits underlying brain function in health and disease. However, it is currently unknown whether mice could perceive arbitrary optogenetic stimulation in addition to their evoked physiological functions. To address this issue, mice were trained to report an optogenetic stimulation as a cue to obtain rewards and avoid punishments. It was found that mice could perceive optogenetic manipulations regardless of the brain area modulated, their rewarding effects, or the stimulation of glutamatergic, GABAergic, and dopaminergic cell types. We named this phenomenon optoception. Using optoception, mice could learn to execute two different sets of instructions based on the laser frequency. Importantly, optoception can occur either activating or silencing a single cell type. Our findings revealed that mices brains are capable of "monitoring" their self-activity, albeit indirectly, perhaps via interoception or as a discriminative stimulus, opening a new way to introduce information to the brain and control brain-computer interfaces.

neuroscience↗

bioRxiv2020

Lateral Hypothalamic GABAergic neurons encode and potentiate sucrose palatability

Sucrose is attractive to most species in the animal kingdom, not only because it induces a sweet taste sensation but also for its positive palatability (i.e., oromotor responses elicited by increasing sucrose concentrations). Although palatability is such an important sensory attribute, it is currently unknown which cell types encode and modulate sucroses palatability. Studies in mice have shown that activation of GABAergic LHAVgat+ neurons evokes voracious eating; however, it is not known whether these neurons would be driving consumption by increasing palatability. Using optrode recordings, we measured sucroses palatability while VGAT-ChR2 transgenic mice performed a brief access sucrose test. We found a subpopulation of LHAVgat+ neurons encodes palatability by increasing (or decreasing) their activity as a function of the increment in licking responses evoked by sucrose concentrations. Optogenetic gain of function experiments, where mice were able to choose among available water, 3%, or 18% sucrose solution, uncovered that opto-stimulation of LHAVgat+ neurons consistently promoted higher intake of the most palatable stimulus (18% sucrose). In contrast, if they self-stimulated near the less palatable stimulus, some VGAT-ChR2 mice preferred water over 18% sucrose. Unexpectedly, activation of LHAVgat+ neurons increased quinine intake but only during water deprivation, since in sated animals, they failed to promote quinine intake or tolerate an aversive stimulus. Conversely, these neurons promoted overconsumption of sucrose when it was the nearest stimulus. Also, experiments with solid foods further confirmed that these neurons increased food interaction time with the most palatable food available. We conclude that LHAVgat+ neurons increase the drive to consume, but it is potentiated by the palatability and proximity of the tastant.

neuroscience↗

bioRxiv2018

Sucrose Intensity coding and decision-making in taste cortices

Sucroses sweet intensity is one attribute contributing to the overconsumption of high-energy palatable foods. However, it is not known how sucrose intensity is encoded and used to make perceptual decisions by neurons in taste-sensitive cortices. We trained rats in a sucrose intensity discrimination task and found that sucrose evoked a widespread response in neurons recorded in posterior-Insula (pIC), anterior-Insula (aIC), and Orbitofrontal cortex (OFC). Remarkably, only a few Intensity-selective neurons conveyed the most information about sucroses intensity, indicating that for sweetness the gustatory system used a compact and distributed code. Sucrose intensity was encoded in both firing-rates and spike-timing. The pIC, aIC, and OFC neurons tracked movement direction, with OFC neurons yielding the most robust response. aIC and OFC neurons encoded the subjects choices, whereas all three regions tracked reward omission. Overall, these multimodal areas provide a neural representation of perceived sucrose intensity, and of task-related information underlying perceptual decision-making.

neuroscience↗