post-doc talks 10/20/14

Ashesh Dhawale, Ölveczky Lab

• “Role of subcortical circuits in motor skill learning”

Introduction

• Function of basal gangalion not well understood.
  • conflicting annotations
  • invovled in parkinsons, huntingtons
• ‘sequencing chuncking’
  • organizes downstream circuits into groups (based on activity recording experiments).
  • monkey can still learn sequences without BG. speed of choice is a bit slower.

Experiment

• two tap with in-between delay.
• initially the rat tends to tap too frequently, then eventualy strongly learns the tap interval. (takes 30 days to learn).
• need to first teach to tap once. get a beep to know reward has arrived. Computer program trains rats.
• dvelop whole series of additional movements
• don’t require motor cortex to learn this. Do require BG.

Experiment 2

• record from neurons. Film from 3 angles at high speed. Also have acceleratomoter.
• see specific neuron firin at particular events
• some cells fire in between task events very reliably.
• controls sequencing.

Charles Vidoudez, Girguis Lab

• “Deep Sea microorganisms, interactions with their environment, and the tools to study them “
• interest: micro-organism community environment interactions
• techniques: mass spec, metabolomics

intro: vents

• hot fluid, anoxic, low pH, hihg CH4, H2S CO2, all mixing. Organisms use gradient in redox between ocean and vent.
• muscles + symbiotic bacteria combine H2S and O2 and CH4 and O2 to produce energy.

experiment

• current sampling: sample size is limited, time delay is a problem.
• developed in situ mass spec — measure at site.
• can observe consumption of H2S and CH4. More mussels where H2S is more, more use of whatever is more present.

Temporal resolution

• now deployed long term sampling devices. sensors connected to internet via cables.

Ranga Dias, Lyman Lab – 1st physics talk!

• “Insulator-metal transitions in simple molecular solids”
• CS2 and super-conductivity.
• 10 GPA (human on a 1mm needle.
• oxygen metaziles at 60 GPA. becomes superconducting at 100 GPA
• system – squeeze sample between two diamonds (800 to 100 um)
• can generate pressures up to 350 GPa.
• resistivity measurement. Try under pressure: need small probes.
• Bridgeman (Nobel in ’46? for squeezing CS2 and solving the structure). CS3 at 20 GPA
• compressed to 51.2 GPA become metal like – shiny / reflective.
• resistivity drops 8 orders of magnitude when squeezed. Semiconductor in ‘black polymer’ regime. then metal.
• superconductor becomes a perfect diamagnet Completely repels a magnetic field, moves out of the field. (hence magnetic levitation) response (travel without resistance, conduct without resistance).
• Cool and have pressure (60 to 172 GPA) see superconductivity at 5-6 K. (high temp superconductor 150 K.
• Faraday quote to chancellor of UK: use of electricity: some-day you can tax it.