scholarly journals Functional ultrasound imaging of recent and remote memory recall in the associative fear neural network in mice

2021 ◽  
Author(s):  
Gillian Grohs-Metz ◽  
Rebecca Smausz ◽  
John Gigg ◽  
Tobias Boeckers ◽  
Bastian Hengerer
Keyword(s):  
Functional Connectivity ◽  
Memory Retrieval ◽  
Primary Auditory Cortex ◽  
Neural Circuitry ◽  
Remote Memory ◽  
Temporal Association ◽  
Memory Recall ◽  
Memory Encoding ◽  
Translational Model ◽  
Cortical Regions

Emotional learning and memory are affected in numerous psychiatric disorders. At a systems level, however, the underlying neural circuitry is not well defined. Rodent fear conditioning (FC) provides a translational model to study the networks underlying associative memory retrieval. In the current study, functional connectivity among regions related to the cue associative fear network were investigated using functional ultrasound (fUS), a novel imaging technique with great potential for detecting regional neural activity through cerebral blood flow. Behavioral fear expression and fUS imaging were performed one and thirty-one days after FC to assess recent and remote memory recall. Cue-evoked increases in functional connectivity were detected throughout the amygdala, with the lateral (LA) and central (CeA) amygdalar nuclei emerging as major hubs of connectivity, though CeA connectivity was reduced during remote recall. The hippocampus and sensory cortical regions displayed heightened connectivity with the LA during remote recall, whereas interconnectivity between the primary auditory cortex and temporal association areas was reduced. Subregions of the prefrontal cortex exhibited variable connectivity changes, where prelimbic connectivity with the amygdala was refined while specific connections between the infralimbic cortex and amygdalar subregions emerged during remote memory retrieval. Moreover, freezing behavior positively correlated with functional connectivity between hubs of the associative fear network, suggesting that emotional response intensity reflected the strength of the cue-evoked functional network. Overall, our data provide evidence of the functionality of fUS imaging to investigate the neural dynamics of memory encoding and retrieval, applicable in the development of innovative treatments for affective disorders.

Functional Connectivity Relationships Predict Similarities in Task Activation and Pattern Information during Associative Memory Encoding

2014 ◽  
Vol 26 (5) ◽  
pp. 1085-1099 ◽  
Author(s):  
Maureen Ritchey ◽  
Andrew P. Yonelinas ◽  
Charan Ranganath
Keyword(s):  
Functional Connectivity ◽  
Functional Properties ◽  
Associative Memory ◽  
Large Scale ◽  
Memory Task ◽  
Neural Systems ◽  
General Level ◽  
Specific Information ◽  
Memory Encoding ◽  
Cortical Regions

Neural systems may be characterized by measuring functional interactions in the healthy brain, but it is unclear whether components of systems defined in this way share functional properties. For instance, within the medial temporal lobes (MTL), different subregions show different patterns of cortical connectivity. It is unknown, however, whether these intrinsic connections predict similarities in how these regions respond during memory encoding. Here, we defined brain networks using resting state functional connectivity (RSFC) then quantified the functional similarity of regions within each network during an associative memory encoding task. Results showed that anterior MTL regions affiliated with a network of anterior temporal cortical regions, whereas posterior MTL regions affiliated with a network of posterior medial cortical regions. Importantly, these connectivity relationships also predicted similarities among regions during the associative memory task. Both in terms of task-evoked activation and trial-specific information carried in multivoxel patterns, regions within each network were more similar to one another than were regions in different networks. These findings suggest that functional heterogeneity among MTL subregions may be related to their participation in distinct large-scale cortical systems involved in memory. At a more general level, the results suggest that components of neural systems defined on the basis of RSFC share similar functional properties in terms of recruitment during cognitive tasks and information carried in voxel patterns.

scholarly journals Temporal Evolution of Cortical Ensembles Promoting Remote Memory Retrieval

2018 ◽  
Author(s):  
Laura A. DeNardo ◽  
Cindy D. Liu ◽  
William E. Allen ◽  
Eliza L. Adams ◽  
Drew Friedmann ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Memory Retrieval ◽  
Remote Memory ◽  
Memory Specificity ◽  
Systems Consolidation ◽  
Prefrontal Cortical ◽  
Consolidation Model ◽  
Learned Fear ◽  
Cortical Regions ◽  
Targeted Recombination

Studies of amnesic patients and animal models support a systems consolidation model, which posits that explicit memories formed in hippocampus are transferred to cortex over time1–6. Prelimbic cortex (PL), a subregion of the medial prefrontal cortex, is required for the expression of learned fear memories from hours after learning until weeks later7–12. While some studies suggested that prefrontal cortical neurons active during learning are required for memory retrieval13–15, others provided evidence for ongoing cortical circuit reorganization during memory consolidation10,16,17. It has been difficult to causally relate the activity of cortical neurons during learning or recent memory retrieval to their function in remote memory, in part due to a lack of tools18. Here we show that a new version of ‘targeted recombination in active populations’, TRAP2, has enhanced efficiency over the past version, providing brain-wide access to neurons activated by a particular experience. Using TRAP2, we accessed PL neurons activated during fear conditioning or 1-, 7-, or 14-day memory retrieval, and assessed their contributions to 28-day remote memory. We found that PL neurons TRAPed at later retrieval times were more likely to be reactivated during remote memory retrieval, and more effectively promoted remote memory retrieval. Furthermore, reducing PL activity during learning blunted the ability of TRAPed PL neurons to promote remote memory retrieval. Finally, a series of whole-brain analyses identified a set of cortical regions that were densely innervated by memory-TRAPed PL neurons and preferentially activated by PL neurons TRAPed during 14-day retrieval, and whose activity co-varied with PL and correlated with memory specificity. These findings support a model in which PL ensembles underlying remote memory undergo dynamic changes during the first two weeks after learning, which manifest as increased functional recruitment of cortical targets.

scholarly journals Imaging recent to very remote object-in-place memories in the medial temporal lobe and prefrontal cortex

2020 ◽  
Author(s):  
Erika Atucha ◽  
Celia Fuerst ◽  
Magdalena Sauvage
Keyword(s):  
Memory Retrieval ◽  
Medial Temporal Lobe ◽  
Brain Regions ◽  
Remote Memory ◽  
General Mechanism ◽  
Cortical Areas ◽  
Prefrontal Cortical ◽  
Place Task ◽  
Cortical Regions ◽  
Over Time

Studies on patient H.M inspired many experiments on the role of the hippocampus and the neocortex in retrieving recent and remote memories. Cortical regions become increasingly engaged for memory retrieval over time, while conflicting results emerge regarding the engagement of the hippocampus, suggested to be ongoing by some or restricted to the retrieval of recent memories by others. In the study of Lux et al, 2016 we tested that this discrepancy might stem from failing to dissociate CA1 from CA3s contribution to memory retrieval over time as CA3 is known to support computations more sensitive to time than CA1. We also reported that parahippocampal cortical areas with tied anatomical connections with the hippocampus were increasingly engaged over time (Lux et al., elife , 2016). This study used a fear conditioning paradigm as emotionally arousing experiences are better remembered than memories devoid of fear content. Here we address whether the differential contribution of brain regions is a general mechanism also subserving memory retrieval devoid of fear content. We succeeded in developing an object-in-place task to investigate remote memory retrieval up to 6 months and the contribution of CA1, CA3, parahippocampal and prefrontal cortical areas to the retrieval of recent versus very remote memories using a high resolution molecular imaging technique based on the detection of the IEG RNA Arc. Preliminary results show that the disengagement of CA3 and persistent engagement of CA1 seem to be a general mechanism in supporting retrieval of remote memory for events.

scholarly journals Age-related Changes in the Sleep-dependent Reorganization of Declarative Memories

2016 ◽  
Vol 28 (6) ◽  
pp. 792-802 ◽  
Author(s):  
Bengi Baran ◽  
Janna Mantua ◽  
Rebecca M. C. Spencer
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Functional Connectivity ◽  
Memory Retrieval ◽  
Slow Wave Sleep ◽  
Memory Performance ◽  
Memory Recall ◽  
Functional Brain ◽  
Age Related ◽  
Age Related Changes

Consolidation of declarative memories has been associated with slow wave sleep in young adults. Previous work suggests that, in spite of changes in sleep, sleep-dependent consolidation of declarative memories may be preserved with aging, although reduced relative to young adults. Previous work on young adults shows that, with consolidation, retrieval of declarative memories gradually becomes independent of the hippocampus. To investigate whether memories are similarly reorganized over sleep at the neural level, we compared functional brain activation associated with word pair recall following a nap and equivalent wake in young and older adults. SWS during the nap predicted better subsequent memory recall and was negatively associated with retrieval-related hippocampal activation in young adults. In contrast, in older adults there was no relationship between sleep and memory performance or with retrieval-related hippocampal activation. Furthermore, compared with young adults, postnap memory retrieval in older adults required strong functional connectivity of the hippocampus with the PFC, whereas there were no differences between young and older adults in the functional connectivity of the hippocampus following wakefulness. These results suggest that, although neural reorganization takes place over sleep in older adults, the shift is unique from that seen in young adults, perhaps reflecting memories at an earlier stage of stabilization.

Influence of Primary Auditory Cortex in the Characterization of Autism Spectrum in Young Adults using Brain Connectivity Parameters and Deep Belief Networks: An fMRI Study

2020 ◽  
Vol 16 (9) ◽  
pp. 1059-1073
Author(s):  
Vidhusha Srinivasan ◽  
N. Udayakumar ◽  
Kavitha Anandan
Keyword(s):  
Functional Connectivity ◽  
Auditory Cortex ◽  
Language Processing ◽  
Brain Connectivity ◽  
Primary Auditory Cortex ◽  
Autism Spectrum ◽  
Belief Networks ◽  
Deep Belief Networks ◽  
High Functioning ◽  
Low Functioning

Background: The spectrum of autism encompasses High Functioning Autism (HFA) and Low Functioning Autism (LFA). Brain mapping studies have revealed that autism individuals have overlaps in brain behavioural characteristics. Generally, high functioning individuals are known to exhibit higher intelligence and better language processing abilities. However, specific mechanisms associated with their functional capabilities are still under research. Objective: This work addresses the overlapping phenomenon present in autism spectrum through functional connectivity patterns along with brain connectivity parameters and distinguishes the classes using deep belief networks. Methods: The task-based functional Magnetic Resonance Images (fMRI) of both high and low functioning autistic groups were acquired from ABIDE database, for 58 low functioning against 43 high functioning individuals while they were involved in a defined language processing task. The language processing regions of the brain, along with Default Mode Network (DMN) have been considered for the analysis. The functional connectivity maps have been plotted through graph theory procedures. Brain connectivity parameters such as Granger Causality (GC) and Phase Slope Index (PSI) have been calculated for the individual groups. These parameters have been fed to Deep Belief Networks (DBN) to classify the subjects under consideration as either LFA or HFA. Results: Results showed increased functional connectivity in high functioning subjects. It was found that the additional interaction of the Primary Auditory Cortex lying in the temporal lobe, with other regions of interest complimented their enhanced connectivity. Results were validated using DBN measuring the classification accuracy of 85.85% for high functioning and 81.71% for the low functioning group. Conclusion: Since it is known that autism involves enhanced, but imbalanced components of intelligence, the reason behind the supremacy of high functioning group in language processing and region responsible for enhanced connectivity has been recognized. Therefore, this work that suggests the effect of Primary Auditory Cortex in characterizing the dominance of language processing in high functioning young adults seems to be highly significant in discriminating different groups in autism spectrum.

scholarly journals Linking the Rapid Cascade of Visuo-Attentional Processes to Successful Memory Encoding

2020 ◽  
Author(s):  
B R Geib ◽  
R Cabeza ◽  
M G Woldorff
Keyword(s):  
Visual Processing ◽  
Memory Retrieval ◽  
Current Knowledge ◽  
High Temporal Resolution ◽  
Alpha Power ◽  
Attentional Orienting ◽  
Memory Encoding ◽  
Attentional Processes ◽  
Neural Processes ◽  
Dm Effect

Abstract While it is broadly accepted that attention modulates memory, the contribution of specific rapid attentional processes to successful encoding is largely unknown. To investigate this issue, we leveraged the high temporal resolution of electroencephalographic recordings to directly link a cascade of visuo-attentional neural processes to successful encoding: namely (1) the N2pc (peaking ~200 ms), which reflects stimulus-specific attentional orienting and allocation, (2) the sustained posterior-contralateral negativity (post-N2pc), which has been associated with sustained visual processing, (3) the contralateral reduction in oscillatory alpha power (contralateral reduction in alpha > 200 ms), which has also been independently related to attentionally sustained visual processing. Each of these visuo-attentional processes was robustly predictive of successful encoding, and, moreover, each enhanced memory independently of the classic, longer-latency, conceptually related, difference-due-to memory (Dm) effect. Early latency midfrontal theta power also promoted successful encoding, with at least part of this influence being mediated by the later latency Dm effect. These findings markedly expand current knowledge by helping to elucidate the intimate relationship between attentional modulations of perceptual processing and effective encoding for later memory retrieval.

scholarly journals An inhibitory hippocampal–thalamic pathway modulates remote memory retrieval

2021 ◽  
Author(s):  
Gisella Vetere ◽  
Frances Xia ◽  
Adam I. Ramsaran ◽  
Lina M. Tran ◽  
Sheena A. Josselyn ◽  
...  
Keyword(s):  
Memory Retrieval ◽  
Remote Memory

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.

scholarly journals Effects of amnesia on processing in the hippocampus and default mode network during a naturalistic memory task: a case study

2018 ◽  
Author(s):  
Christiane Oedekoven ◽  
James L. Keidel ◽  
Stuart Anderson ◽  
Angus Nisbet ◽  
Chris Bird
Keyword(s):  
Functional Connectivity ◽  
Episodic Memory ◽  
Memory Performance ◽  
Memory Task ◽  
Structural Mri ◽  
Brain Regions ◽  
Left Hippocampus ◽  
Cortical Regions ◽  
The Right ◽  
Encoding And Retrieval

Despite their severely impaired episodic memory, individuals with amnesia are able to comprehend ongoing events. Online representations of a current event are thought to be supported by a network of regions centred on the posterior midline cortex (PMC). By contrast, episodic memory is widely believed to be supported by interactions between the hippocampus and these cortical regions. In this MRI study, we investigated the encoding and retrieval of lifelike events (video clips) in a patient with severe amnesia likely resulting from a stroke to the right thalamus, and a group of 20 age-matched controls. Structural MRI revealed grey matter reductions in left hippocampus and left thalamus in comparison to controls. We first characterised the regions activated in the controls while they watched and retrieved the videos. There were no differences in activation between the patient and controls in any of the regions. We then identified a widespread network of brain regions, including the hippocampus, that were functionally connected with the PMC in controls. However, in the patient there was a specific reduction in functional connectivity between the PMC and a region of left hippocampus when both watching and attempting to retrieve the videos. A follow up analysis revealed that in controls the functional connectivity between these regions when watching the videos was correlated with memory performance. Taken together, these findings support the view that the interactions between the PMC and the hippocampus enable the encoding and retrieval of multimodal representations of the contents of an event.

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