The neural correlates of attending to external (semantic) and internal (episodic) stimuli
Poster No:
1085
Submission Type:
Abstract Submission
Authors:
Chen Chen1, Katya Krieger-Redwood1, Elizabeth Jefferies1
Institutions:
1Department of Psychology, University of York, York, United Kingdom
First Author:
Co-Author(s):
Introduction:
Semantic cognition supports different thoughts and behaviours, e.g., making sense of information from the external world, such as comprehension of what we are reading or listening to [1, 2], but also generating thoughts and memories that are independent of the external environment [3]. Using functional MRI, the current study explores how activation changes when participants (i) attend to external information, (ii) generate internally or (iii) ignore external semantic inputs for internally-focused autobiographical recall.
Methods:
This study occurred across two consecutive days. On day 1, participants generated personal memories linked to cue words (e.g., gift) outside the scanner. On day 2, participants recalled these memories from the cue word in the scanner, and also read and listened to factual sentences in a comprehension task. The experiment consisted of the following conditions (1) sentence reading; (2) sentence listening; (3) personal memory retrieval ignoring written sentences or (4) spoken sentences; (5) personal memory retrieval (no conflicting sentence presented). After each trial, task focus ratings on a scale of 1 (i.e., not at all focused) to 4 (i.e., highly focused) were collected to index the extent to which participants were able to focus on the current task.
30 participants were recruited (18-23 Years, 24 females, 4 excluded). We performed a univariate analysis using a general linear model (GLM) to identify neural differences across these tasks and parametric effects of task focus.
30 participants were recruited (18-23 Years, 24 females, 4 excluded). We performed a univariate analysis using a general linear model (GLM) to identify neural differences across these tasks and parametric effects of task focus.
Results:
Behaviorally, the task focus ratings showed that participants were more focused in the comprehension than the recall task and that ignoring auditory input was harder than ignoring visual sentences during recall. Neurally, when participants attended to external information, activation spread along STG for auditory inputs, and along the ventral visual stream for visual inputs. These meaning pathways were activated automatically, even when participants focused their attention internally to recall personal memories, whilst ignoring the external input. When participants did not have to ignore external inputs, activation was higher in medial prefrontal and posterior cingulate cortex.
The parametric effects of focus revealed differential engagement of default mode network (DMN) subsystems and control/salience networks. Greater task focus for external auditory or visual information was associated with greater activation in the dorsomedial DMN subsystem, previously been shown to be involved in semantic cognition [4] and auditory network and increased deactivation in the core DMN, salience and control-B networks. In contrast, greater task focus for internal memory generation, ignoring external information, correlated with increased activation in medial temporal and some core DMN, as well as somatomotor networks, and deactivation in dorsomedial and other aspects of core DMN. In this way, core DMN showed a functional split between task-positive and negative responses. Greater focus on internal generation, regardless of external distractions or not, was correlated with increased deactivation in salience and control-B networks. Compared to internal memory generation, dorsomedial DMN showed a stronger effect of task focus for comprehension of external inputs, while core DMN showed a stronger effect of task focus for recall, relative to comprehension.
The parametric effects of focus revealed differential engagement of default mode network (DMN) subsystems and control/salience networks. Greater task focus for external auditory or visual information was associated with greater activation in the dorsomedial DMN subsystem, previously been shown to be involved in semantic cognition [4] and auditory network and increased deactivation in the core DMN, salience and control-B networks. In contrast, greater task focus for internal memory generation, ignoring external information, correlated with increased activation in medial temporal and some core DMN, as well as somatomotor networks, and deactivation in dorsomedial and other aspects of core DMN. In this way, core DMN showed a functional split between task-positive and negative responses. Greater focus on internal generation, regardless of external distractions or not, was correlated with increased deactivation in salience and control-B networks. Compared to internal memory generation, dorsomedial DMN showed a stronger effect of task focus for comprehension of external inputs, while core DMN showed a stronger effect of task focus for recall, relative to comprehension.
Conclusions:
Focus on external semantic information is associated with activation in dorsomedial DMN, while activation of core and medial temporal DMN regions is linked to focus on internal memory generation. When participants ignore semantic inputs and increase focus internally, activation increases in medial temporal and core DMN and somatomotor networks, and decreases across control networks. This study finds differential activation and deactivation of DMN subsystems, as opposed to recruitment of control systems, are aligned to our capacity to flexibly focus on internal memory generation and external semantic processing.
Higher Cognitive Functions:
Higher Cognitive Functions Other
Language:
Language Comprehension and Semantics 2
Learning and Memory:
Long-Term Memory (Episodic and Semantic) 1
Modeling and Analysis Methods:
Activation (eg. BOLD task-fMRI)
Keywords:
Other - semantic cognition; reading; listening
1|2Indicates the priority used for review
Provide references using author date format
[2] Spitsyna, G., J. E. Warren, S. K. Scott, F. E. Turkheimer and R. J. Wise (2006). "Converging language streams in the human temporal lobe." J Neurosci 26(28): 7328-7336.
[3] Smallwood, J. and J. W. Schooler (2015). "The science of mind wandering: empirically navigating the stream of consciousness." Annu Rev Psychol 66: 487-518.
[4] Zhang, M., B. C. Bernhardt, X. Wang, D. Varga, K. Krieger-Redwood, J. Royer, R. Rodriguez-Cruces, R. Vos de Wael, D. S. Margulies, J. Smallwood and E. Jefferies (2022). "Perceptual coupling and decoupling of the default mode network during mind-wandering and reading." Elife 11.