Review on Research Methods Flashcards
The most basic classification of methods in neuroscience is:
Morphological methods versus functional methods
If we need to identify the change of a protein and to see where this change occurs, which research method we need to use?
Immunohistology: We used this technique to identify protein change
If we want to see cellular structure of neurons, which methods are used?
Fixation
Cutting tissue into thin slice
Inject dye into neuron
3-D reconstruction: if neuron is bigger than the slice
Behavioral tests are: (4)
Functional
Subjective
Active or Passive
May be simple observations or empirical
Electrodes: (4)
- Must have conductive material as core
- Can be made from glass pipette : need to feel the pipette with conductive solution
- Insulation, only the solution inside is conductive which we need for spatial selectivity and record measurement from the tipInsulation prevents signals go across different electrode
Select signal from tip (more important for microelectrode). - Circuits are from a loop between two electrodes
Characteristics of gross electrodes: (6)
Gross: Less invasive
Worst spatial selectivity
Near and Far field
Lower impedance, sturdier
Low level of Noise
Narrow Signal amplitude
Characteristics of Microelectrodes: (6)
Micro: More invasive
better Spatial Selectivity
Near Field
Higher impedance more fragile
High level of Noise
Larger Signal amplitude
To test a single-channel activity from a small patch of cell membrane in culture: (5)
Functional
In vitro
Near-field
Spontaneous and evoked
Objective
The coding mechanisms of individual neurons must be observed with:
Microelectrode
can be both In vivo and in vitro
So far, we know that the coding behaviors of auditory neurons are seen in change of: (4)
Spike Rate in response to Frequency and/or Intensity change
Timing (e.g, Phase locking)
Place Coding
Threshold of single neurons
Neurons with different functions and morphologies are located in different places. This localization difference is called:
Segregation
Transient auditory evoked responses include: (2)
ABR
ECochG
An Evoked response is ___________than spontaneous EEG because__________________________
is Smaller than spontaneous EEG because it is often embedded in the noise
How can evoked responses be detected by the computer?
Time-Averaging to depress the noise so the signal can stand out of the noise
ABR is transient AER requiring stronger synchrony because: (3)
- Smaller number of Neurons because of the peripheral
- Deep location
- Short AP duration.
Why is Click evoked ABR best represent hearing in 2-5 kHz? (2)
- Upper limit of its power spectrum produce by clicks
In E-signal (0.08-0.1 ms pulses)
By transducer - Traveling wave speeds higher at higher frequency region
For better synchrony
For a good recording of AER, the surface electrodes must be:
In the same orientation of the dipole generator
What are the general changes of AER from low to high levels: (5)
- Increased amplitude
- Reduced Transient
- Less clear generator
- Later maturation in development
- Influence of sleep
- Longer latency
- More involvement of cognition
What the 5 Classifications methods of auditory evoked response:
- By latency (most popular)
- By Stim-R(time) relationship
3.. endogenous versus exogenous (also stim-R relationship, but emphasize on subject participation) - By distance between electrodes and generator
- By generator
What are the advantages and generators of Steady-state response?
Steady: Continuous signals showing periodicity
Advantages: Better Frequency selectivity because of the longer duration of signals
Dependent on signal periodicity
The generator is not so clear compared to ABR
Odd-ball paradigm:
Two types of stimuli with a fixed ratio
Random presentation of odd stimuli among the common (or frequent) one
Responses averaged separately
Used in MMN and cognitive response
What is the similarity and difference between mismatch negativity?
It is an Event-Related Potential, but not cognitive
Elicited by discriminable changes in signal
No attention is needed
But based upon memory train established by preceding (standard) stimulus
Explain near-field amplitude, spatial selectivity, electrode, and neuronal structure:
Near field: larger amplitude, larger change if distance changes, better spacial selectivity, microelectrode, Electrodes close to the generator
closed field of neuronal structure
Explain Far field amplitude, spatial selectivity, electrode, and neuronal structure:
Poor spatial selectivity
smaller amplitude
Gross electrodes
open field of neuronal structure