Hi, welcome!
I can't give you a specifyc solution since you are not providing a REPRoducible EXample (reprex) but you can do something like this.
library(dplyr)
library(tidyr)
# Made up sample data
df <- data.frame(AOI_name = c("patient", "agent"),
Start_Bin = c(2, 10),
End_Bin = c(6, 14))
df %>%
gather(x, Bin, ends_with("Bin")) %>%
select(-x) %>%
group_by(AOI_name) %>%
complete(Bin = full_seq(Bin, period = 1))
#> # A tibble: 10 x 2
#> # Groups: AOI_name [2]
#> AOI_name Bin
#> <fct> <dbl>
#> 1 agent 10
#> 2 agent 11
#> 3 agent 12
#> 4 agent 13
#> 5 agent 14
#> 6 patient 2
#> 7 patient 3
#> 8 patient 4
#> 9 patient 5
#> 10 patient 6
Created on 2019-06-24 by the reprex package (v0.3.0)