{"doi":"10.7554/elife.85069.2.sa3","title":"Author Response: Mega-scale movie-fields in the mouse visuo-hippocampal network","abstract":"Natural experience often involves a continuous series of related images while the subject is immobile. How does the cortico-hippocampal circuit process this information? The hippocampus is crucial for episodic memory–, but most rodent single unit studies require spatial exploration– or active engagement7. Hence, we investigated neural responses to a silent, isoluminant, black and white movie in head-fixed mice without any task or locomotion demands, or rewards, from the Allen Brain Observatory. The activity of most neurons (97%, 6554/6785) in the thalamo-cortical visual areas was significantly modulated by the 30s long movie clip. Surprisingly, a third (33%, 3379/10263) of hippocampal –dentate gyrus, CA1 and subiculum– neurons showed movie-selectivity, with elevated firing in specific movie sub-segments, termed movie-fields. Movie-tuning remained intact when mice were immobile or ran spontaneously. On average, a tuned cell had more than 5 movie-fields in visual areas, but only 2 in hippocampal areas. The movie-field durations in all brain regions spanned an unprecedented 1000-fold range: from 0.02s to 20s, termed mega-scale coding. Yet, the total duration of all the movie-fields of a cell was comparable across neurons and brain regions. We hypothesize that hippocampal responses show greater continuous-sequence encoding than visual areas, as evidenced by fewer and broader movie-fields than in visual areas. Consistent with this hypothesis, repeated presentation of the movie images in a fixed, scrambled sequence virtually abolished hippocampal but not visual-cortical selectivity. The enhancement of continuous movie tuning compared to the scrambled sequence was eight-fold greater in hippocampal than visual areas, further supporting episodic-sequence encoding. Thus, all mouse-brain areas investigated encoded segments of the movie. Similar results are likely to hold in primates and humans. Hence, movies could provide a unified way to probe neural mechanisms of episodic information processing and memory, even in immobile subjects, across brain regions, and species.","journal":null,"year":2023,"id":411465,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9486,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":553998,"name":"Mayank Mehta","orcid":"0000-0003-2005-2468","position":1,"is_corresponding":false},{"id":819513,"name":"Chinmay S. Purandare","orcid":null,"position":0,"is_corresponding":true}],"reference_count":0,"raw_metadata":null,"created_at":"2026-07-19T01:21:42.971455Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}