Inhibitory control..

Check out the latest, a preview of Hardung et al., 2017 for Current Biology.

Functional anatomy in frontal cortex has been elusive and controversial. Here we preview a new study which combines neuronal ensemble recordings and optogenetics to map a functional gradient in rodent prefrontal cortex that supports inhibitory control.

Figure 1, Narayanan & Laubach, 2017

NS Narayanan, M Laubach, (2017). Inhibitory control: mapping medial frontal cortex. Current Biology 27 (4), R148-R150

Who regulates palatability? mPFC (through a lot of receptors)!

Our latest work is now published in Frontiers in Behavioral Neuroscience!

Here, we demonstrate that both systemic and mPFC infusions of the muscarinic receptor antagonist scopolamine decreased the duration of licking bouts during access to high value sucrose solutions when provided alternating access to high and low value solutions. These results are similar to what has been previously reported following reversible inactivation of mPFC (Parent et al., 2015), and suggest that blocking mACh receptors with scopolamine disrupts the same elements of neuronal processing that is similarly affected by total cortical inactivation via muscimol. Exactly the opposite result was obtained when cholinergic tone was enhanced locally in mPFC with infusion of the cholinesterase inhibitor physostigmine (aka eserine), activation of mAChR with the mAChR agonist oxotremorine, and blocking KCNQ channels linked to mAChR receptors with XE-991. Furthermore, infusion of ghrelin, which acts on the same KCNQ channels as the muscarinic system enhanced the same measure of palatability (bout duration) only when the high value sucrose solution was available. The present study is the first to implicate cholinergic and ghrelinergic signaling in the mPFC, acting through KCNQ channels, in the expression of palatability.

Figure 2, Parent et al., 2017

MA Parent, LM Amarante, K Swanson, M Laubach, (2017). Cholinergic and ghrelinergic receptors and KCNQ channels in the medial PFC regulate the expression of palatability. Frontiers in behavioral neuroscience 9, 284

Persistent licking and incentive contrast

In the latest issue of Frontiers in Integrative Neuroscience we report on the role of medial prefrontal cortex in reward processing and the control of consummatory behaviors.

In this study we found that pharmacological inactivations of the mPFC, specifically the rostral part of the prelimbic area, greatly reduced intake of higher value fluid and only slightly increased intake of lower value fluid in an incentive contrast licking task. We also found rats licked equally for the high and low levels of sucrose at the beginning of the test sessions and “relearned” to reduce intake of the low value fluid over the test sessions. These effects were verified using optogenetic silencing of the same region and were distinct from inactivation of the ventral striatum, which simply increased overall intake. Our findings suggest that the mPFC is crucial for the maintenance of persistent licking and the expression of learned feeding strategies.

Figure 3, Parent et al., (2015).

MA Parent, LM Amarante, B Liu, D Weikum, M Laubach (2015). The medial prefrontal cortex is crucial for the maintenance of persistent licking and the expression of incentive contrast. Frontiers in integrative neuroscience 9, 23

Mistakes were made…

Excited to see our new published work out in the special issue of Journal of Physiology-Paris!

Here we report evidence for a role of mPFC in stimulus detection and time estimation. Event-related potentials in mPFC are triggered by actions and action-imperative stimuli. The ERPs are coterminous with major changes in neuronal population activity. These events might serve as “time markers” denoting transitions between waiting and acting. We propose a mechanism based on these signals that changes behavior after mistakes are made.

Figure 10, Laubach et al. 2015

M Laubach, MS Caetano, NS Narayanan (2015). Mistakes were made: neural mechanisms for the adaptive control of action initiation by the medial prefrontal cortex. Journal of Physiology-Paris 109 (1-3), 104-117

For Better or Worse

This week our preview of Strait et al. 2014 came out in Neuron. In their study, Strait et al. found neurons in the monkey vmPFC were commonly influenced by reward magnitude and probability, showed anticorrelation for better and worse options, and covaried with choice independent of value. We further we discuss reward comparison by the vmPFC, the implications of their findings, and pose a few questions to be explored by future research.

Figure 1, Amarante & Laubach, (2014).

LM Amarante, M Laubach (2014). For Better or Worse: Reward Comparison by the Ventromedial Prefrontal Cortex. Neuron 82 (6), 1191-1193