It’s our final must-read list for 2017! These are the papers published in December that stood out as relevant to the community of neuroscientists studying neural circuits. Happy New Year!
1. Combined Social and Spatial Coding in a Descending Projection from the Prefrontal Cortex by Malavika Murugan, Hee Jae Jang, Michelle Park, Ellia M. Miller, Julia Cox, Joshua P. Taliaferro, Nathan F. Parker, Varun Bhave, Hong Hur, Yupu Liang, Alexander R. Nectow, Jonathan W. Pillow, Ilana B. Witten. Cell.
To determine what information the prelimbic cortex to nucleus accumbens neurons convey, they recorded from them (including by using the Inscopix nVista system) and found that individual neurons in the nucleus accumbens were active during social investigation, but only in specific spatial locations.
2. Infrabarrels are Layer 6 Circuit Modules in the Barrel Cortex that Link Long-Range Inputs and Outputs by Shane R. Crandall, Saundra L. Patrick, Scott J. Cruikshank, and Barry W. Connors. Cell Reports.
Because it receives and sends out so many connections, layer 6 of the cortex is an intriguing region to study and serves as a hub for sensory processing. Here in layer 6 they see barrel-like structures called infrabarrels that include distinct excitatory circuits linking thalamic inputs with specific outputs, suggesting a cortical architecture not previously appreciated.
3. Modulation of SF1 Neuron Activity Coordinately Regulates Both Feeding Behavior and Associated Emotional States by Paulius Viskaitis, Elaine E. Irvine, Mark A. Smith, Agharul I. Choudhury, Elisa Alvarez-Curto, Justyna A. Glegola, Darran G. Hardy, Silvia M.A. Pedroni, Maria R. Paiva Pessoa, Anushka B.P. Fernando, Loukia Katsouri, Alessandro Sardini, Mark A. Ungless, Graeme Milligan, Dominic J. Withers. Cell Reports.
By using the Inscopix nVista system they show that Intrinsic SF1 neuron activity is low during feeding and increases when feeding stops. Activating SF1 neurons in the ventromedial hypothalamus decrease feeding and fat mass, but increase anxiety. In contrast, the inhibition of SF1 neurons increases feeding and fat mass and decreases anxiety. The implications for understanding a neural circuit mechanism of feeding and neuropsychiatric disorders are intriguing.
4. Reward-Based Learning Drives Rapid Sensory Signals in Medial Prefrontal Cortex and Dorsal Hippocampus Necessary for Goal-Directed Behavior by Pierre Le Merre, Vahid Esmaeili, Eloïse Charrière, Katia Galan, Paul-A. Salin, Carl C.H. Petersen, Sylvain Crochet. Neuron.
They “demonstrated a fast and differential recruitment of sensory and high-order cortical areas. Whereas sensory areas responded regardless of the context, processing in dCA1 and mPFC depended upon learning.”
Read more here
5. Neuromodulatory Control of Long-Term Behavioral Patterns and Individuality across Development
Shay Stern, Christoph Kirst, Cornelia I. Bargmann. Cell.
This is a really cool worm genetics and behavior study on roaming, and it opens up further investigation into the neuromodulatory circuits. They show that neuromodulatory systems regulate long-term stereotypical patterns in spontaneous behaviour across and within developmental stages and persistent behavioural biases that are exhibited by some individuals.
6. Cholinergic projections to the substantia nigra reticulata inhibit dopamine modulation of basal ganglia through the M4 muscarinic receptor. Moehle, M.S., Pancani, T., Byun, N., Yohn, S.E., Wilson, G.H. III, Dickerson, J.W., Remke, D.H., Xiang, Z., Niswender, C.M., Wess, J. et al. Neuron.
They “demonstrate that presynaptic muscarinic receptors counteract the effects of dopamine in an output nucleus of the basal ganglia. They provide intracellular, anatomical, and network-level mechanisms for this cholinergic-dopaminergic interplay.”
7. RORβ Spinal Interneurons Gate Sensory Transmission during Locomotion to Secure a Fluid Walking Gait by Stephanie C. Koch, Marta Garcia Del Barrio, Antoine Dalet, Graziana Gatto, Thomas Günther, Jingming Zhang, Barbara Seidler, Dieter Saur, Roland Schüle, Martyn Goulding. Neuron.
RORβ inhibitory neurons function to suppress the sensory transmission pathways that activate flexor motor reflexes and interfere with the ongoing locomotor program.
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8. Inhibiting Mesolimbic Dopamine Neurons Reduces the Initiation and Maintenance of Instrumental Responding by Sarah Fischbach-Weiss, Rebecca M. Reese, Patricia H. Janak. Neuroscience.
They optogenetically inhibited midbrain tyrosine hydroxylase (TH)+ neurons to probe the role of dopamine neuron activity during instrumental responding (operant conditioning done in discrete trials) for reward.
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9. Removal of perineuronal nets disrupts recall of a remote fear memory by Elise Holter Thompson, Kristian Kinden Lensjø, Mattis Brænne Wigestrand, Anders Malthe-Sørenssen, Torkel Hafting, Marianne Fyhn. PNAS.
What’s the mechanism by which perineuronal nets help physically establish memories? It’s thought that PNNs enwrap the synaptic connections stabilizing their size and placement, and this study tests that hypothesis. They asked whether intact PNNs in the lateral secondary visual cortex (V2L), a cortical region important for remote memory, are required for the processing of remote visual fear memories.
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10. Generation of a whole-brain atlas for the cholinergic system and mesoscopic projectome analysis of basal forebrain cholinergic neurons by Xiangning Li, Bin Yu, Qingtao Sun, Yalun Zhang, Miao Ren, Xiaoyan Zhang, Anan Li, Jing Yuan, Linda Madisen, Qingming Luo, Hongkui Zeng, Hui Gong, and Zilong Qiu. PNAS.
This study gives a three-dimensional picture of neural projections across the mouse brain. They divide cholinergic neurons into three categories including cortical VIP neurons, long-range projection neurons, and brainstem motor neurons. After reconstructing the cholinergic neurons in a subregion of basal forebrain, they found that their projections to the forebrain and midbrain showed neuronal subgroups with distinct projection specificity.
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11. Distinct Inhibitory Circuits Orchestrate Cortical beta and gamma Band Oscillations by Guang Chen, Yuan Zhang, Xiang Li, Xiaochen Zhao, Qian Ye, Yingxi Lin, Huizhong W. Tao, Malte J. Rasch, Xiaohui Zhang. Neuron.
By recording optogenetically tagged interneurons of specific subtypes in the primary visual cortex of behaving mice, they show that spiking of somatostatin and parvalbumin-expressing interneurons preferentially correlates with cortical beta and gamma band oscillations, respectively
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12. Midbrain circuit regulation of individual alcohol drinking behaviors in mice by Barbara Juarez, Carole Morel, Stacy M. Ku, Yutong Liu, Hongxing Zhang, Sarah Montgomery, Hilledna Gregoire, Efrain Ribeiro, Marshall Crumiller, Ciorana Roman-Ortiz, Jessica J. Walsh, Kelcy Jackson, Denise E. Croote, Yingbo Zhu, Song Zhang, Leandro F. Vendruscolo, Scott Edward, Amanda Roberts, Georgia E. Hodes, Yongke Lu, Erin S. Calipari, Dipesh Chaudhury, Allyson K. Friedman & Ming-Hu Han. Nature Communications.
“Mice exposed to a two-bottle alcohol choice paradigm can be divided into high and low drinking groups. Here, the authors show that stimulating VTA neurons to induce higher phasic activity patterns that are observed in low alcohol drinking mice, suppresses alcohol drinking in mice that are high alcohol drinking.”
Read more here