Congratulations to Sue Ann Koay, who is starting up her own group at Janelia!

Sue Ann Koay, Stephan Thiberge, Carlos Brody, David Tank, “Amplitude Modulations of Cortical Sensory Responses in Pulsatile Evidence Accumulation.” eLife 2020.

How does the brain internally represent a sequence of sensory information that jointly drives a decision-making behavior? Studies of perceptual decision-making have often assumed that sensory cortices provide noisy but otherwise veridical sensory inputs to downstream processes that accumulate and drive decisions. However, sensory processing in even the earliest sensory cortices can be systematically modified by various external and internal contexts. We recorded from neuronal populations across posterior cortex as mice performed a navigational decision-making task based on accumulating randomly timed pulses of visual evidence. Even in V1, only a small fraction of active neurons had sensory-like responses time-locked to each pulse. Here, we focus on how these ‘cue-locked’ neurons exhibited a variety of amplitude modulations from sensory to cognitive, notably by choice and accumulated evidence. These task-related modulations affected a large fraction of cue-locked neurons across posterior cortex, suggesting that future models of behavior should account for such influences.

Thomas Luo*, Adrian Bondy*, Diksha Gupta, Verity Elliott, Charles Kopec, Carlos Brody, “An approach for long-term, multi-probe Neuropixels recordings in unrestrained rats”, eLife 2020

The use of Neuropixels probes for chronic neural recordings is in its infancy and initial studies leave questions about long-term stability and probe reusability unaddressed. Here, we demonstrate a new approach for chronic Neuropixels recordings over a period of months in freely moving rats. Our approach allows multiple probes per rat and multiple cycles of probe reuse. We found that hundreds of units could be recorded for multiple months, but that yields depended systematically on anatomical position. Explanted probes displayed a small increase in noise compared to unimplanted probes, but this was insufficient to impair future single-unit recordings. We conclude that cost-effective, multi-region, and multi-probe Neuropixels recordings can be carried out with high yields over multiple months in rats or other similarly sized animals. Our methods and observations may facilitate the standardization of chronic recording from Neuropixels probes in freely moving animals.

Congratulations to postdoc Athena Akrami, who has accepted a faculty position at the Sainsbury Wellcome Centre in London!!! She expects to start there in Fall 2018.

Ben Scott

Congratulations to postdoc Ben Scott, who has accepted a faculty position at Boston University!!! He expects to start there in Fall 2018.

Whoopeee!!  The Howard Hughes Medical Institute has renewed its appointment of Carlos Brody as an HHMI Investigator for another 7 years!

HHMI’s support is critical to the entire lab. The renewal is thanks to the fantastic work of everyone in the lab!

Alex Piet

Congratulations to graduate student Alex Piet, whose paper in Neural Computation is now out (link here).

In this paper Alex uses two-node attractor network models to  figure out what neural mechanisms could lead to FOF (a rat cortical region) contributing to decision-making as the lab found in Erlich et al. eLife 2015 and Erlich et al. Neuron 2011. Alex’s results point to specific mechanisms in which the FOF contributes “post-categorization” memory, and make some predictions that Alex then confirmed as correct in a post-hoc analysis of the data.

Congratulations to ex-graduate student (now Dr.) Kevin Miller, who just had a paper published in Nature Neuroscience, on developing a planning task for rats together with computational methods to analyse the rats’ behavior, and using those to establish a role for the hippocampus in planning. Link to the paper is here.

Christine Constantinople

Ben Scott

Congratulations to Ben Scott and Christine Constantinople, co-first authors of a paper in Neuron describing how calcium imaging recordings during accumulation of evidence reveal that evidence is encoded in heterogeneous neural responses that have a wide diversity of timescales.