Remembering and imagining differentially engage the hippocampus: A multivariate fMRI investigation

Decoding the emotional valence of future thoughts

Affective future thinking allows us to prepare for future outcomes, but we know little about neural representation of emotional future simulations. We used a multi-voxel pattern analysis to determine whether patterns of neural activity can reliably distinguish between positive and negative future simulations. Neural patterning in the anterior cingulate and ventromedial prefrontal cortices distinguished positive from negative future simulations, indicating that these regions code for the emotional valence of future events. These results support prior findings that anterior medial regions contain representations of emotions across various stimuli, and contribute to identifying potential rewarding outcomes of future events. More broadly, these results demonstrate that the phenomenological features of future thinking can be decoded using neural activity.

Cartesian critters can't remember

Descartes held the following view of declarative memory: to remember is to reconstruct an idea that you intellectually recognize as a reconstruction. Descartes countenanced two overarching varieties of declarative memory. To have an intellectual memory is to intellectually reconstruct a universal idea that you recognize as a reconstruction, and to have a sensory memory is to neurophysiologically reconstruct a particular idea that you recognize as a reconstruction. Sensory remembering is thus a capacity of neither ghosts nor machines, but only of human beings qua mind-body unions. This interpretation unifies Descartes's various remarks (and conspicuous silences) about remembering, from the 1628 Rules for the Direction of the Mind through the suppressed-in-1633 Treatise of Man to the 1649 Passions of the Soul. It also rebuts a prevailing thesis in the current secondary literature-that Cartesian critters can remember-while incorporating the textual evidence for that thesis-Descartes's detailed descriptions of the corporeal mechanisms that construct sensory memories.

Episodic Future Thinking: Mechanisms and Functions

Episodic future thinking refers to the capacity to imagine or simulate experiences that might occur in one's personal future. Cognitive, neuropsychological, and neuroimaging research concerning episodic future thinking has accelerated during recent years. This article discusses research that has delineated cognitive and neural mechanisms that support episodic future thinking as well as the functions that episodic future thinking serves. Studies focused on mechanisms have identified a core brain network that underlies episodic future thinking and have begun to tease apart the relative contributions of particular regions in this network, and the specific cognitive processes that they support. Studies concerned with functions have identified several domains in which episodic future thinking produces performance benefits, including decision making, emotion regulation, prospective memory, and spatial navigation.

Specifying the core network supporting episodic simulation and episodic memory by activation likelihood estimation

It has been suggested that the simulation of hypothetical episodes and the recollection of past episodes are supported by fundamentally the same set of brain regions. The present article specifies this core network via Activation Likelihood Estimation (ALE). Specifically, a first meta-analysis revealed joint engagement of expected core-network regions during episodic memory and episodic simulation. These include parts of the medial surface, the hippocampus and parahippocampal cortex within the medial temporal lobes, and the temporal and inferior posterior parietal cortices on the lateral surface. Both capacities also jointly recruited additional regions such as parts of the bilateral dorsolateral prefrontal cortex. All of these core regions overlapped with the default network. Moreover, it has further been suggested that episodic simulation may require a stronger engagement of some of the core network's nodes as well as the recruitment of additional brain regions supporting control functions. A second ALE meta-analysis indeed identified such regions that were consistently more strongly engaged during episodic simulation than episodic memory. These comprised the core-network clusters located in the left dorsolateral prefrontal cortex and posterior inferior parietal lobe and other structures distributed broadly across the default and fronto-parietal control networks. Together, the analyses determine the set of brain regions that allow us to experience past and hypothetical episodes, thus providing an important foundation for studying the regions' specialized contributions and interactions.