Poster C56, Wednesday, August 21, 2019, 10:45 am – 12:30 pm, Restaurant Hall
Tip-of-the-Tongue: A window into neural interactions between memory and language systems
James Hartzell1, Pedro Paz-Alonso1;1Basque Center on Cognition Brain and Language (BCBL)
Verbal recall is a complex and only partly-understood brain function. In particular, it is still unclear why on many occasions we quickly and accurately remember a person's name or the label for an object or place, yet on other occasions we experience variable delays in recall. During Tip-of-the-Tongue (ToT) experiences, neurologically healthy individuals transiently fail to recall target names or words yet nevertheless recall context, eventually accessing the target via associations and circumlocutions. ToTs provide an excellent window into the interaction of neural circuitries typically associated with mnemonic and language processes: ToTs can occur for both newly-learned episodic target word memories or for long-established semantic target-word memories. To investigate the ToT phenomenon, we therefore contrasted recall of target words from both episodic and semantic memories in a behavioral-fMRI study with 30 healthy young adult participants. On Day 1 participants learned 200 new face-name pairs using testing effect methods. On Day 2 they were scanned using fMRI while viewing the same newly learned faces randomly intermixed with 200 famous faces. Participants responded with a button-press indicating whether face-names were Known, ToT, Familiar (recognized without knowledge of the name), or Unknown, and were asked to confirm their in-scanner responses both verbally and with multiple choice tests during a behavioral session immediately following the fMRI session. Preliminary results showed overlapping networks underpinning successful, delayed, and partial retrieval of both episodic and semantic memories for face-name pairs. Successful (Known) semantic-memory face-name recall recruited a broad bilateral frontoparietal network linked to the hippocampal formation, while successful episodic face-name recall engaged a subset of regions within the same network. Semantic-memory ToTs recruited a similar network to that for semantic-memory Known with the additional involvement of basal ganglia, thalamic nuclei, insula, and cingulate cortex, together with bilateral precuneus. Episodic-memory ToTs recruited a subset of regions of the semantic-ToT network, with less widely engaged frontoparietal circuits. Both semantic- and episodic-memory Familiar engaged similar frontoparietal networks with greater right-lateralized activation for semantic, and greater left-lateralized activity for episodic memories. These results suggest that semantic memory access (Known condition), search (ToT condition) and facial recognition (Familiar condition) recruit a more widespread memory network than comparable episodic memory conditions, further elucidating the underlying neuroanatomical circuitry involved in verbal recall.
Themes: Language Production, Control, Selection, and Executive Processes
Method: Functional Imaging