Behavior is often not static across a trial – animals may switch strategy or change their search patterns as the trial progresses. If you analyze the trial as a whole, your results will blur together early, mid, and late behaviors, potentially missing critical transitions or not recognising specific behavior that ocurred at a specific stage of the trial.
Time slicing allows you to focus on the phase of the behavior that’s most scientifically relevant to your study and to the type of trial being analyzed, e.g.:
- Initial search strategy
- Memory retrieval attempts
- Realization of platform being moved or absent in reversal learning or probe trials
- Strategy shifts (e.g., allocentric to egocentric)
This gives you precise, accurate data and allows you to make more meaningful cross-trial and cross-subject comparisons.
In the HVS Image system you can quickly and easily set any time slice you want to focus on – just click the Advanced button and enter the slice start time and duration. For example, to analyze the first 20 seconds, set a start time of 0 and a duration of 20; to analyze a slice starting at 25 seconds after the trial start and lasting15 seconds, enter a start time of 25 and a duration of 15. You will then get plots and analysis for the time slice set, including results specific to that time slice for multiple trials analyzed as a batch, such as an entire experiment or a series of probe trials.
You may find time-sliced analysis particularly useful for the following:
Probe trials
Get a cleaner measure of spatial memory recall by analysing just the early phase of your probe trials.
The first 10–20 seconds after release are the best indicator of where the animal expects the platform to be, before it gives up or starts a new search. Set the slice start to 0 and duration to 10 or 20 to analyze only the first 10 or 20 seconds. (To decide how long a duration to set for your analysis, you may find it useful to use the multi-pool feature to view multiple plots with a particular slice duration, then view the plots again with different slice durations, in order to see which duration you want to use for your batch analysis.)
Reversal trials
Get sensitive measures of cognitive flexibility and interference from prior learning, by separating initial and subsequent search in reversal trials. After moving the platform, you can assess to what extent the animal initially searches the old location before adjusting (both within trials and over a series of trials). While whole trial measures will show whether or not an animal has a high degree of perseveration, for trials where the original platform location is searched relatively briefly at the start of the trial, time slices will provably show how animals went about the task, e.g. searching the original location first, before moving on to look elsewhere.
Distinguishing motivational deficits from memory deficits
Some treatments or lesions may impair persistence or adaptation, so analysing late-phase search behavior using, for example, a slice start of 40 (to analyze behavior only from 40 seconds into the trial onwards), and comparing it with, for example, the first 30 seconds of the trial, will clearly show whether animals start out searching efficiently but are not able to sustain it vs mediocre performance seen if analyzing the trial as a whole.
Detecting dynamic changes in search strategy
This can be important for understanding complex cognitive processes, where for example animals may start with a goal-directed search and later switch to scanning or thigmotaxis if unsuccessful. Comparing early and late time slices separately for different animals will clearly show similarities and differences in different animals’ initial and subsequent strategies.
Standardizing comparisons
By analyzing just, for example, the first 20 seconds of every trial, you ensure a fair comparison between animals that reached the platform right away and those that almost reached it but just missed, and then went on to take a much longer path. This approach means you capture initial search strategies, which are often more diagnostic of learning and memory, and normalizes behavioral opportunity, removing trial-length bias from the analysis.
In summary, by enabling start-time and duration-controlled slicing, the HVS Image system gives you the ability to:
- Capture precise behavioral phases of trials
- Detect strategy changes
- Improve sensitivity of learning and memory assessments
- Reduce noise from later, less goal-directed behaviors, especially in probe trials
- Generate more reproducible and focused data