Table 1. Movement categories and behavioral matching.

Head movements were sorted into 50 unique movement categories, corresponding to a combination of ten categories of movement start and end positions and five categories of movement duration. Categories are displayed in tables for three example time points. Movements from different sessions that fell into the same category of start position, distance, and duration were considered a “matched set”. In accordance with our previous work, only categories containing at least five movements on every recorded session were considered for analysis. Underlined firing rates belong to categories with movements on all sessions and would therefore be included in the final analyses.

Average Neural Firing Rates in Spikes/Second (Early: e.g. Day 1)
Duration →	100 -280ms	280-460ms	460-640ms	640-820ms	820-1000ms
Start: End Photocell↓
1:3	2.6	NA	NA	NA	NA
1:4	3.2	2.3	2.8	2.6	NA
1:5	NA	2.6	2.6	NA	1.9
1:6	NA	2.2	2.6	2.6	2.6
2:4	3.6	2.6	2.3	1.6	NA
2:5	3.2	2.9	2.3	1.4	NA
2:6	NA	NA	2.9	2.6	1.5
3:5	4.6	2.8	2.6	2.2	NA
3:6	2.1	1.5	NA	NA	NA
4:6	2.2	2.6	NA	NA	NA

Average Neural Firing Rates in Spikes/Second (Middle: e.g. Day 12)
Duration →	100 -280ms	280-460ms	460-640ms	640-820ms	820-1000ms
Start: End Photocell ↓
1:3	1.6	2.6	NA	NA	NA
1:4	3.1	2.7	NA	2.3	2.2
1:5	NA	2.6	2.3	3.2	1.4
1:6	NA	6.3	2.6	2.6	2.7
2:4	3.6	2.6	2.5	NA	NA
2:5	NA	1.4	2.3	1.4	NA
2:6	NA	NA	1.3	2.6	3.2
3:5	4.6	2.6	2.6	1.5	NA
3:6	2.1	2.1	2.7	NA	2.7
4:6	2.2	3.8	2.2	NA	NA

Average Neural Firing Rates in Spikes/Second (Late: e.g. Day 24)
Duration →	100 -280ms	280-460ms	460-640ms	640-820ms	820-1000ms
Start: End Photocell ↓
1:3	2.6	NA	NA	NA	NA
1:4	3.2	2.3	NA	2.6	NA
1:5	NA	2.6	2.4	1.5	1.4
1:6	NA	2.2	NA	1.8	2.2
2:4	3.6	2.6	2.6	1.6	NA
2:5	3.2	1.9	2.3	1.4	NA
2:6	1.7	NA	1.5	2.6	4.2
3:5	4.6	1.4	2.6	2.9	NA
3:6	2.1	2.2	2.6	NA	1.6
4:6	NA	3.6	NA	NA	NA