optogenetics Flashcards
non-invasive brain stimulation
Manipulate brain activity with an external source
– Administered from outside the body
Electrostimulation
Transcranial magnetic stimulation
electrostimulation
- Electric current passed through electrodes on the scalp
– Various stimulation frequencies, positioning, brain targets
– Signal attenuated by skin, scalp, distance, etc
transcranial magnetic stimulation
– Magnetic fields delivered from a coil indue an electric field in brain tissue
– Typically delivered in repetitive trains
– Various stimulation frequencies, brain targets and intensities
invasive brain stimulation
deep brain stimulation
bionic eye
deep brain stimulation
– An electrode is implanted into the brain and delivers electrical stimulation directly to neurons
– Powered by an external battery source
– Managing tremors in Parkinson’s disease
bionic eye
– Electrical prothesis is implanted into the eye, making contact with neurons in the retina.
– Paired with glasses or a camera that captures or filters light and sends this information to the implant, delivering electrical activity in neurons
– Varying levels of restoration of visual perception
* Electrode number
brain stimulation
Problem: Spatial resolution
- In 1979, Francis Crick suggested that controlling a population of cells while not stimulating others is a real challenge for neuroscience
– Suggested using light to control activity
optogenetics
Using light to manipulate/control the activity of neurons
Nature method of the year 2010
Neurons need to be targeted to express light sensitive proteins
High spatial and temporal resolution
opsins
Opsins: GPCRs that respond to light
-Opsin protein covalently bound to a chromophore
-Rhodopsin in rods and OPN1SW, OPN1MW, OPN1LW in cones
Type 2 opsins: Animals
-Chromophore absorbs light causing a conformational change and activates the G protein
-Channels open indirectly
Type 1 opsins: Microbial
