Fellows Lecture in Pairs

Dr Adam Packer: “All-optical interrogation of neural codes across visual, somatosensory, and claustral networks”

The brains of higher organisms are composed of anatomically and functionally distinct regions performing specialised tasks. However, individual regions do not operate in isolation: the orchestration of complex behaviours requires communication between brain regions and reliable transmission of information between them. We study this process directly by generating neural activity that propagates between brain regions and drives behaviour, allowing us to assess how populations of neurons in cortex act in concert to transmit information. We use novel approaches that combine simultaneous two-photon calcium imaging and two-photon targeted optogenetic photostimulation to provide ‘all-optical’ readout and manipulation of the same neurons in vivo. I will discuss our recent results in visual, somatosensory, and claustral networks that adds to existing understanding of cortical function by identifying how population activity is formatted to ensure robust transmission of information.

BIOGRAPHY: Adam studied neuroscience at MIT before completing a PhD with Rafael Yuste. As a postdoc in Michael Häusser’s lab, Adam developed a new approach using two-photon imaging and optogenetics to readout and manipulate neural activity in vivo. His group at Oxford uses all-optical interrogation techniques he helped pioneer to investigate neural coding and the enigmatic claustrum.

Dr Armin Lak: “Dopaminergic circuits for perceptual decisions”

Dopamine neurons are the brain’s central hub for economic decision making. However, the roles these neurons play in perceptual decision making have remained largely unknown. Combining behaviour, optical imaging and optogenetics in mice, we have shown that during perceptual decisions dopamine neurons of the ventral tegmental area encode sensory decision confidence, in addition to reward value. Computational modelling showed that these neural responses conform with teaching signals of normative learning models under perceptual uncertainty. In our more recent work, we have investigated the diversity of dopamine signals during perceptual decisions, showing that the roles of dopamine signals in perceptual decisions strongly depend on their projection target in the striatum. In our current experimental and theoretical works in the lab, we are investigating the roles of dopamine circuits during learning, when naïve animals learn to make perceptual decisions, aiming to determine the computational roles of these circuits in long-term learning from naïve to expert performance.

BIOGRAPHY: Armin completed his PhD in neuroscience at University of Cambridge in 2013 working with Wolfram Schultz and investigating the roles of midbrain dopamine neurons in economic decision making. He was then awarded a Henry Wellcome Postdoctoral fellowship to work between Cold Spring Harbor Lab in New York and UCL in London. During this fellowship, Armin combined neuronal circuit tools with novel behavioural and computational methods to investigate the roles that frontal cortex and dopamine neurons play in perceptual and economic decisions. Since 2019, Armin has been a group leader in DPAG,Oxford funded by a Wellcome Trust Dale fellowship. His lab employs electrophysiological, optical, behavioural and computational tools to study neural signals underlying learning and decision making.