For instance, 'a ramp-like increase (or decrease) of neural activity that peaks at the end of a timed interval'. Can I repace 'timed interval' with 'time interval' without changing the original meaning?
A time interval is just that, the amount of time between a start and finish time.
From 12:00 to 12:15 is a 15 minute time interval
A timed interval is a specific amount of time that has been purposely measured as in an athletic competition
Runners were started at timed intervals
A timed interval is an interval of time, but an interval of time is not necessarily a timed interval