Representation of the Temporal Order of Visual Objects in the Primate Lateral Prefrontal Cortex

2003 ◽  
Vol 89 (5) ◽  
pp. 2868-2873 ◽  
Author(s):  
Yoshihisa Ninokura ◽  
Hajime Mushiake ◽  
Jun Tanji
Keyword(s):  
Prefrontal Cortex ◽  
Temporal Order ◽  
Motor Behavior ◽  
Delay Period ◽  
Order Information ◽  
Cellular Activity ◽  
Lateral Prefrontal Cortex ◽  
Visual Objects ◽  
Multiple Sequences

Recollecting a past episode involves remembering the temporal order of events. We studied cellular activity in the lateral prefrontal cortex (PFC) of two monkeys that were required to remember the temporal order in which visual objects appeared and to reach for each object in the same order after a delay. Here, we report the cellular activity in the lateral PFC, focusing on the delay period. We found that 43% of the delay-period activity was selective for the sequence in which the visual objects were presented during the cue period. While the majority of cellular activity was selective for multiple sequences, some cells (31%) were selective for only one of six sequences. Our findings show that PFC cells are involved in holding temporal order information when that information is necessary for planning forthcoming motor behavior.

Integration of Temporal Order and Object Information in the Monkey Lateral Prefrontal Cortex

2004 ◽  
Vol 91 (1) ◽  
pp. 555-560 ◽  
Author(s):  
Yoshihisa Ninokura ◽  
Hajime Mushiake ◽  
Jun Tanji
Keyword(s):  
Prefrontal Cortex ◽  
Physical Properties ◽  
Temporal Order ◽  
Motor Behavior ◽  
Rank Order ◽  
Distinct Group ◽  
Cellular Activity ◽  
Lateral Prefrontal Cortex ◽  
Visual Objects ◽  
Temporal Sequences

Generation of information about the temporal order of events is essential for the control of memory-based behavioral tasks. We studied cellular activity in the lateral prefrontal cortex (LPFC) in two monkeys that were required to remember the temporal order in which visual objects were presented. In this report, we focus on cellular activity in response to the sequential appearance of three different objects. We identified cells that responded selectively to physical properties (color and shape) of objects (23%) in the ventral part of the LPFC and cells for which activity was selective for the numerical position (rank order) of objects (44%) in the dorsal part of the LPFC. We also identified cells for which activity was selective for both the physical properties and rank order of objects (30%). The third type of cells, distributed in the ventral LPFC, seems of importance in integrating the two categories of information, i.e., physical and temporal information about the occurrences of objects to construct sequential order information. Furthermore, we identified a distinct group of cells that exhibited selectivity for the sequence of presentation of the three objects. Our findings suggest that LPFC cells are involved in encoding temporal sequences of events when such information is required for planning forthcoming motor behavior.

Models of Functional Organization of the Lateral Prefrontal Cortex in Verbal Working Memory: Evidence in Favor of the Process Model

2002 ◽  
Vol 14 (7) ◽  
pp. 1054-1063 ◽  
Author(s):  
Laura H. F. Barde ◽  
Sharon L. Thompson-Schill
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Phonological Processing ◽  
Process Model ◽  
Functional Organization ◽  
Verbal Working Memory ◽  
Delay Period ◽  
Process Models ◽  
Delayed Response ◽  
Lateral Prefrontal Cortex

Research on the functional organization of the lateral prefrontal cortex (PFC) in working memory continues to be fairly equivocal between two major frameworks: organization-by-process or organization-by-material. Although there is fairly strong evidence for organization-by-process models from event-related fMRI studies, some investigators argue that the nature of the stimulus material better defines the functional organization of the lateral PFC, particularly in more ventral regions (BA 47/45/44). Specifically, the anterior region of the ventrolateral PFC (BA 47/45) is hypothesized to subserve semantic processing while the posterior region (BA 44) may subserve phonological processing. In the current event-related fMRI study, we directly compared process-related versus material-related organizational principles in a verbal working memory task. Subjects performed a modified delayed response task in which they (1) retained a list of five words or five nonwords during the delay period (“maintenance”), or (2) performed a semantic (size reordering) or phonological (alphabetical reordering) task on the word or nonword lists, respectively (“manipulation”). We did not find evidence during the delay period of our task to support claims of anterior-posterior specializations in the ventrolateral PFC for semantic versus phonological processing. Subjects did, however, display greater neuronal activity during the delay period of manipulation trials than maintenance trials in both the dorsolateral PFC and posterior ventrolateral regions. These data are more consistent with the process model of the organization of lateral PFC in verbal working memory.

scholarly journals Convergence of heteromodal lexical retrieval in the lateral prefrontal cortex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alexander A. Aabedi ◽  
Sofia Kakaizada ◽  
Jacob S. Young ◽  
Jasleen Kaur ◽  
Olivia Wiese ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Picture Naming ◽  
Cognitive Rehabilitation ◽  
Tumor Model ◽  
Brain Regions ◽  
Support Vector ◽  
Lexical Retrieval ◽  
Lateral Prefrontal Cortex ◽  
Lesion Symptom Mapping ◽  
Single Construct

AbstractLexical retrieval requires selecting and retrieving the most appropriate word from the lexicon to express a desired concept. Few studies have probed lexical retrieval with tasks other than picture naming, and when non-picture naming lexical retrieval tasks have been applied, both convergent and divergent results emerged. The presence of a single construct for auditory and visual processes of lexical retrieval would influence cognitive rehabilitation strategies for patients with aphasia. In this study, we perform support vector regression lesion-symptom mapping using a brain tumor model to test the hypothesis that brain regions specifically involved in lexical retrieval from visual and auditory stimuli represent overlapping neural systems. We find that principal components analysis of language tasks revealed multicollinearity between picture naming, auditory naming, and a validated measure of word finding, implying the existence of redundant cognitive constructs. Nonparametric, multivariate lesion-symptom mapping across participants was used to model accuracies on each of the four language tasks. Lesions within overlapping clusters of 8,333 voxels and 21,512 voxels in the left lateral prefrontal cortex (PFC) were predictive of impaired picture naming and auditory naming, respectively. These data indicate a convergence of heteromodal lexical retrieval within the PFC.

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