Control the source: Source memory for semantic, spatial and self-related items in patients with LIFG lesions

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neurolinguistics

Background:

• Patients with semantic aphasia exhibit deficits in controlled conceptual retrieval despite intact knowledge.
• Controlled retrieval processes may overlap between semantic and episodic memory domains.

Purpose of the Study:

• To investigate the overlap in controlled retrieval processes between semantic and episodic memory in patients with semantic aphasia.
• To examine item familiarity and source memory for recent events in semantic aphasia.

Main Methods:

• Assessed item familiarity and source memory in patients with semantic aphasia following left inferior frontal gyrus infarcts.
• Manipulated factors influencing retrieval competition, source distinctiveness, and cue strength.

Main Results:

• Episodic judgements in semantic aphasia reflect retrieval control deficits, with familiarity being more intact than source recollection.
• Impairment was strongest with high source competition and incongruent knowledge.
• Source memory improved with strong spatial cues, congruent knowledge, and self-referential processing.

Conclusions:

• Confirms the link between deregulated control of semantic and episodic memory in semantic aphasia.
• Identifies circumstances that can ameliorate or aggravate episodic memory deficits in these patients.