TB10 L1 – Representation in individual neurons
Single Unit Firing rates
recordings - Neurons act like detectors and activates when is detected
- Firing rate varies in different representations
- Sensory, motor and cognitive sensors
- Through integrating information from sources Send signals reflecting
degree of inputs and matching pattern
- Factors can be determined that affect the firing rate of a given neuron
Neurons and Neuron – Cells specialized for receiving and propagating signals
tuning curves - Dendrites Cell body for action potential Axon
- Via chemical signals Electrical impulse
Technique for recording
- Extracellular single unit recording
- Via input electrodes in brain areas To record single neurons
Amplitude of action potential
- Resting potential
- With passive responses
- *Action potentials are approximately the same amplitude (All or
nothing)
- Therefore focus on frequency of generated AP
- Raster plot (Spike amount) + Peristimulus histogram (Firing in period)
- Onset Increased activation post 0-400ms
- AKA Rate coding – Rate at which cell fires
Sensory neurons – Cell response to particular stimulus properties (Ringach et al.,
2002)
- Cell specific activation in cats – Orientation, space…
- particular part of visual field
- Edge orientated + particular directions
- Able to plot spike rate with tuning curve
Tuning curves (Bell shaped)
- Not only to sensory information
- Properties of receptive fields
Examples of Cognitive neurons – Head Direction cells in rats (Taube et al., 1990)
representation - Hippocampus – Respond to direction of animal
in individual - Implanted electrode in rat hippocampus
neurons - Rat runs around an enclosed environment with orientation
(Animals) - Cells firing more in specific direction, despite different stimuli seen
- E.g. Strong fire rate when moving south, but also activates when
roughly south, yet less strong Bell shaped curve
Motor neurons – Reaction to direction of hand movements (Georgopoulous et
al., 1982)
- Monkeys only react to specific directional movements of hand
Single Unit Firing rates
recordings - Neurons act like detectors and activates when is detected
- Firing rate varies in different representations
- Sensory, motor and cognitive sensors
- Through integrating information from sources Send signals reflecting
degree of inputs and matching pattern
- Factors can be determined that affect the firing rate of a given neuron
Neurons and Neuron – Cells specialized for receiving and propagating signals
tuning curves - Dendrites Cell body for action potential Axon
- Via chemical signals Electrical impulse
Technique for recording
- Extracellular single unit recording
- Via input electrodes in brain areas To record single neurons
Amplitude of action potential
- Resting potential
- With passive responses
- *Action potentials are approximately the same amplitude (All or
nothing)
- Therefore focus on frequency of generated AP
- Raster plot (Spike amount) + Peristimulus histogram (Firing in period)
- Onset Increased activation post 0-400ms
- AKA Rate coding – Rate at which cell fires
Sensory neurons – Cell response to particular stimulus properties (Ringach et al.,
2002)
- Cell specific activation in cats – Orientation, space…
- particular part of visual field
- Edge orientated + particular directions
- Able to plot spike rate with tuning curve
Tuning curves (Bell shaped)
- Not only to sensory information
- Properties of receptive fields
Examples of Cognitive neurons – Head Direction cells in rats (Taube et al., 1990)
representation - Hippocampus – Respond to direction of animal
in individual - Implanted electrode in rat hippocampus
neurons - Rat runs around an enclosed environment with orientation
(Animals) - Cells firing more in specific direction, despite different stimuli seen
- E.g. Strong fire rate when moving south, but also activates when
roughly south, yet less strong Bell shaped curve
Motor neurons – Reaction to direction of hand movements (Georgopoulous et
al., 1982)
- Monkeys only react to specific directional movements of hand
