Temporal context in human fMRI

- Temporal context memory uses regions also involved in non-temporal context memory.
- PFC is involved in relative recency judgments for both short and long lag probes.
- Relative recency paradigms with short lags find PHc and hippocampal activation.
- PHc is less involved in temporal memory for repeatedly encoded sequences.
- Implicit tasks find hippocampal and PHc representations are sensitive to temporal context.

Memory for personally experienced events includes temporal context that allows organization and retrieval according to sequence. This review compares fMRI studies of temporal context, assessing the processes required within each paradigm. Prefrontal cortex is important for temporal sequence memory, perhaps due to its role in organizing information online, and relative recency judgments, perhaps due to its role in evaluating familiarity. Hippocampal and parahippocampal regions are also involved in these tasks but make reduced contributions to relative recency when familiarity is diagnostic. Parahippocampal cortex contributions to accurate sequence memory are also reduced when multiple encoding repetitions are used. Finally, implicit temporal memory paradigms show that hippocampal and parahippocampal representations are sensitive to temporal context in the absence of mnemonic task demands.