New Study

Evidence for a neural law of effect. Science. 2018
Athalye VR, Santos FJ, Carmena JM, Costa RM.

When we learn a new skill or task, our movements are reinforced and shaped. Learning occurs because the neural activity patterns in the movement control–related brain regions that are rewarded are repeated. But how does this reinforcement work? Athalye et al. developed a closed-loop self-stimulation paradigm in which a target motor cortical activity pattern resulted in the optogenetic stimulation of dopaminergic neurons. With training, mice learned to reenter specific neuronal activity patterns, which triggered self-stimulation and shaped their neural activity to be closer to the target pattern.

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Gabriela Martins
New Study

Dopamine neuron activity before action initiation gates and invigorates future movements. Nature. 2018
da Silva JA, Tecuapetla F, Paixão V, Costa RM.

Abstract
Deciding when and whether to move is critical for survival. Loss of dopamine neurons (DANs) of the substantia nigra pars compacta (SNc) in patients with Parkinson’s disease causes deficits in movement initiation and slowness of movement. The role of DANs in self-paced movement has mostly been attributed to their tonic activity, whereas phasic changes in DAN activity have been linked to reward prediction. This model has recently been challenged by studies showing transient changes in DAN activity before or during self-paced movement initiation. Nevertheless, the necessity of this activity for spontaneous movement initiation has not been demonstrated, nor has its relation to initiation versus ongoing movement been described. Here we show that a large proportion of SNc DANs, which did not overlap with reward-responsive DANs, transiently increased their activity before self-paced movement initiation...

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Gabriela Martins
New Study

Sleeping sickness is a circadian disorder. Nature Communications. 2018
Rijo-Ferreira F, Carvalho T, Afonso C, Sanches-Vaz M, Costa RM, Figueiredo LM, Takahashi JS.

Abstract

Sleeping sickness is a fatal disease caused by Trypanosoma brucei, a unicellular parasite that lives in the bloodstream and interstitial spaces of peripheral tissues and the brain. Patients have altered sleep/wake cycles, body temperature, and endocrine profiles, but the underlying causes are unknown. Here, we show that the robust circadian rhythms of mice become phase advanced upon infection, with abnormal activity occurring during the rest phase. This advanced phase is caused by shortening of the circadian period both at the behavioral level as well as at the tissue and cell level...

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Gabriela Martins
New study

The Spatiotemporal Organization of the Striatum Encodes Action Space. Neuron. 2017
Klaus A, Martins GJ, Paixao VB, Zhou P, Paninski L, Costa RM.

Abstract

Activity in striatal direct- and indirect-pathway spiny projection neurons (SPNs) is critical for proper movement. However, little is known about the spatiotemporal organization of this activity. We investigated the spatiotemporal organization of this activity. We investigated the spatiotemporal organization of SPN ensemble activity in mice during self-paced...

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Myles Marshall
New review

Design and manufacturing challenges of optogenetic neural interfaces: a review
S B Goncalves, J F Ribeiro, A F Silva, R M Costa, and J H Correia
 

Abstract

Optogenetics is a relatively new technology to achieve cell-type specific neuromodulation with millisecond-scale temporal precision. Optogenetic tools are being developed to address neuroscience challenges, and to improve the knowledge about brain networks, with the ultimate aim of catalyzing new...
 

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Myles Marshall