Top-Down Signal of Retrieved Information From Prefrontal to Inferior Temporal Cortices

2007 ◽  
Vol 98 (4) ◽  
pp. 1965-1974 ◽  
Author(s):  
Masato Inoue ◽  
Akichika Mikami
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Temporal Cortex ◽  
Inferior Temporal Cortex ◽  
Critical Area ◽  
Retrieval Process ◽  
Multiple Objects ◽  
Top Down ◽  
Ventrolateral Prefrontal Cortex

We compared neuronal activities in the ventrolateral prefrontal cortex (VLPFC) and the inferior temporal cortex (IT) during the retrieval of an object from the working memory. About one third of IT neurons showed color- and target-selective (CT) or target-selective (T) response during the color cue period of the serial probe reproduction (SPR) task. These object-selective (CT and T) responses in IT could be correlated with the retrieval process of an object from the memorized multiple objects because no objects were presented during this period. However, proportion of CT and T responses was smaller in IT than in VLPFC, where two thirds of neurons showed object-selective response. In addition, object-selective response started earlier in VLPFC than in IT. These results suggest that VLPFC retrieves particular object information from the working memory and sends the retrieved object information to IT. The fact that the responses in the error trials did not decrease in IT suggests that IT is not a critical area for the retrieval process from the working memory.

scholarly journals Tomita H, Ohbayashi M, Nakahara K, Hasegawa I, Miyashita Y

1999 ◽  
Vol 7 (6) ◽  
pp. E14
Author(s):  
William T. Couldwell
Keyword(s):  
Prefrontal Cortex ◽  
Executive Control ◽  
Temporal Cortex ◽  
Inferior Temporal Cortex ◽  
Association Cortex ◽  
Long Term Memory ◽  
Top Down ◽  
Visual Inputs ◽  
Voluntary Recall ◽  
Show Evidence

Knowledge or experience is voluntarily recalled from memory by reactivation of the neural representations in the cerebral association cortex. In inferior temporal cortex, which serves as the storehouse of visual long-term memory, activation of mnemonic engrams through electric stimulation results in imagery recall in humans, and neurons can be dynamically activated by the necessity for memory recall in monkeys. Neuropsychological studies and previous split-brain experiments predicted that prefrontal cortex exerts executive control upon inferior temporal cortex in memory retrieval; however, no neuronal correlate of this process has ever been detected. Here we show evidence of the top-down signal from prefrontal cortex. In the absence of bottom-up visual inputs, single inferior temporal neurons were activated by the top-down signal, which conveyed information on semantic categorization imposed by visual stimulus-stimulus association. Behavioural performance was severely impaired with loss of the top-down signal. Control experiments confirmed that the signal was transmitted not through a subcortical but through a fronto-temporal cortical pathway. Thus, feedback projections from prefrontal cortex to the posterior association cortex appear to serve the executive control of voluntary recall.

scholarly journals Towards understanding of the cortical network underlying associative memory

2008 ◽  
Vol 363 (1500) ◽  
pp. 2187-2199 ◽  
Author(s):  
Takahiro Osada ◽  
Yusuke Adachi ◽  
Hiroko M Kimura ◽  
Yasushi Miyashita
Keyword(s):  
Prefrontal Cortex ◽  
Medial Temporal Lobe ◽  
Temporal Cortex ◽  
Neural Mechanism ◽  
Neural Representation ◽  
Association Cortex ◽  
Retrieval Process ◽  
Top Down ◽  
Automatic Retrieval ◽  
Local Circuits

Declarative knowledge and experiences are represented in the association cortex and are recalled by reactivation of the neural representation. Electrophysiological experiments have revealed that associations between semantically linked visual objects are formed in neural representations in the temporal and limbic cortices. Memory traces are created by the reorganization of neural circuits. These regions are reactivated during retrieval and contribute to the contents of a memory. Two different types of retrieval signals are suggested as follows: automatic and active. One flows backward from the medial temporal lobe during the automatic retrieval process, whereas the other is conveyed as a top-down signal from the prefrontal cortex to the temporal cortex during the active retrieval process. By sending the top-down signal, the prefrontal cortex manipulates and organizes to-be-remembered information, devises strategies for retrieval and monitors the outcome. To further understand the neural mechanism of memory, the following two complementary views are needed: how the multiple cortical areas in the brain-wide network interact to orchestrate cognitive functions and how the properties of single neurons and their synaptic connections with neighbouring neurons combine to form local circuits and to exhibit the function of each cortical area. We will discuss some new methodological innovations that tackle these challenges.

scholarly journals Organization of cortico-cortical pathways supporting memory retrieval across subregions of the left ventrolateral prefrontal cortex

2016 ◽  
Vol 116 (3) ◽  
pp. 920-937 ◽  
Author(s):  
Jennifer Barredo ◽  
Timothy D. Verstynen ◽  
David Badre
Keyword(s):  
Prefrontal Cortex ◽  
White Matter ◽  
Functional Connectivity ◽  
Memory Retrieval ◽  
Temporal Cortex ◽  
Functional Network ◽  
High Angular Resolution ◽  
Connectivity Analysis ◽  
Ventrolateral Prefrontal Cortex ◽  
Functional Connectivity Analysis

Functional magnetic resonance imaging (fMRI) evidence indicates that different subregions of ventrolateral prefrontal cortex (VLPFC) participate in distinct cortical networks. These networks have been shown to support separable cognitive functions: anterior VLPFC [inferior frontal gyrus (IFG) pars orbitalis] functionally correlates with a ventral fronto-temporal network associated with top-down influences on memory retrieval, while mid-VLPFC (IFG pars triangularis) functionally correlates with a dorsal fronto-parietal network associated with postretrieval control processes. However, it is not known to what extent subregional differences in network affiliation and function are driven by differences in the organization of underlying white matter pathways. We used high-angular-resolution diffusion spectrum imaging and functional connectivity analysis in unanesthetized humans to address whether the organization of white matter connectivity differs between subregions of VLPFC. Our results demonstrate a ventral-dorsal division within IFG. Ventral IFG as a whole connects broadly to lateral temporal cortex. Although several different individual white matter tracts form connections between ventral IFG and lateral temporal cortex, functional connectivity analysis of fMRI data indicates that these are part of the same ventral functional network. By contrast, across subdivisions, dorsal IFG was connected with the midfrontal gyrus and correlated as a separate dorsal functional network. These qualitative differences in white matter organization within larger macroanatomical subregions of VLPFC support prior functional distinctions among these regions observed in task-based and functional connectivity fMRI studies. These results are consistent with the proposal that anatomical connectivity is a crucial determinant of systems-level functional organization of frontal cortex and the brain in general.

Increasing top-down suppression from prefrontal cortex facilitates tactile working memory

NeuroImage ◽  
2010 ◽  
Vol 49 (1) ◽  
pp. 1091-1098 ◽  
Author(s):  
Henri Hannula ◽  
Tuomas Neuvonen ◽  
Petri Savolainen ◽  
Jaana Hiltunen ◽  
Yuan-Ye Ma ◽  
...  
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Top Down ◽  
Tactile Working Memory

scholarly journals Dynamic Population Coding of Category Information in Inferior Temporal and Prefrontal Cortex

2008 ◽  
Vol 100 (3) ◽  
pp. 1407-1419 ◽  
Author(s):  
Ethan M. Meyers ◽  
David J. Freedman ◽  
Gabriel Kreiman ◽  
Earl K. Miller ◽  
Tomaso Poggio
Keyword(s):  
Prefrontal Cortex ◽  
Visual Information ◽  
Activity Patterns ◽  
Temporal Cortex ◽  
Relevant Information ◽  
Population Coding ◽  
Inferior Temporal Cortex ◽  
Category Information ◽  
Almost All ◽  
Dynamic Population

Most electrophysiology studies analyze the activity of each neuron separately. While such studies have given much insight into properties of the visual system, they have also potentially overlooked important aspects of information coded in changing patterns of activity that are distributed over larger populations of neurons. In this work, we apply a population decoding method to better estimate what information is available in neuronal ensembles and how this information is coded in dynamic patterns of neural activity in data recorded from inferior temporal cortex (ITC) and prefrontal cortex (PFC) as macaque monkeys engaged in a delayed match-to-category task. Analyses of activity patterns in ITC and PFC revealed that both areas contain “abstract” category information (i.e., category information that is not directly correlated with properties of the stimuli); however, in general, PFC has more task-relevant information, and ITC has more detailed visual information. Analyses examining how information coded in these areas show that almost all category information is available in a small fraction of the neurons in the population. Most remarkably, our results also show that category information is coded by a nonstationary pattern of activity that changes over the course of a trial with individual neurons containing information on much shorter time scales than the population as a whole.

A Comparison of Abstract Rules in the Prefrontal Cortex, Premotor Cortex, Inferior Temporal Cortex, and Striatum

2006 ◽  
Vol 18 (6) ◽  
pp. 974-989 ◽  
Author(s):  
Rahmat Muhammad ◽  
Jonathan D. Wallis ◽  
Earl K. Miller
Keyword(s):  
Prefrontal Cortex ◽  
Neural Activity ◽  
Premotor Cortex ◽  
Temporal Cortex ◽  
Dorsal Striatum ◽  
Behavioral Responses ◽  
Inferior Temporal Cortex ◽  
Perceptual Information ◽  
Lateral Prefrontal Cortex

The ability to use abstract rules or principles allows behavior to generalize from specific circumstances. We have previously shown that such rules are encoded in the lateral prefrontal cortex (PFC) and premotor cortex (PMC). Here, we extend these investigations to two other areas directly connected with the PFC and the PMC, the inferior temporal cortex (ITC) and the dorsal striatum (STR). Monkeys were trained to use two abstract rules: “same” or “different”. They had to either hold or release a lever, depending on whether two successively presented pictures were the same or different, and depending on which rule was in effect. The rules and the behavioral responses were reflected most strongly and, on average, tended to be earlier in the PMC followed by the PFC and then the STR; few neurons in the ITC reflected the rules or the actions. By contrast, perceptual information (the identity of the pictures used as sample and test stimuli) was encoded more strongly and earlier in the ITC, followed by the PFC; they had weak, if any, effects on neural activity in the PMC and STR. These findings are discussed in the context of the anatomy and posited functions of these areas.

scholarly journals Reduced visual and frontal cortex activation during visual working memory in grapheme-colour synaesthetes relative to young and older adults

2018 ◽  
Author(s):  
Gaby Pfeifer ◽  
Jamie Ward ◽  
Natasha Sigala
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Visual Cortex ◽  
Visual Working Memory ◽  
Temporal Cortex ◽  
Region Of Interest ◽  
Inferior Temporal Cortex ◽  
Long Term Memory ◽  
Sensory Recruitment ◽  
Recruitment Model

AbstractThe sensory recruitment model envisages visual working memory (VWM) as an emergent property that is encoded and maintained in sensory (visual) regions. The model implies that enhanced sensory-perceptual functions, as in synaesthesia, entail a dedicated VWM-system, showing reduced visual cortex activity as a result of neural specificity. By contrast, sensory-perceptual decline, as in old age, is expected to show enhanced visual cortex activity as a result of neural broadening. To test this model, young grapheme-colour synaesthetes, older adults and young controls engaged in a delayed pair-associative retrieval and a delayed matching-to-sample task, consisting of achromatic fractal stimuli that do not induce synaesthesia. While a previous analysis of this dataset (Pfeifer et al., 2016) has focused on cued retrieval and recognition of pair-associates (i.e. long-term memory), the current study focuses on visual working memory and considers, for the first time, the crucial delay period in which no visual stimuli are present, but working memory processes are engaged. Participants were trained to criterion and demonstrated comparable behavioural performance on VWM tasks. Whole-brain and region-of-interest-analyses revealed significantly lower activity in synaesthetes’ middle frontal gyrus and visual regions (cuneus, inferior temporal cortex) respectively, suggesting greater neural efficiency relative to young and older adults in both tasks. The results support the sensory recruitment model and can explain age and individual WM-differences based on neural specificity in visual cortex.

Sign in / Sign up

Export Citation Format

Share Document