scholarly journals fMRI study of neural sensitization to hedonic stimuli in long‐term, daily cannabis users

2016 ◽  
Vol 37 (10) ◽  
pp. 3431-3443 ◽  
Author(s):  
Francesca M. Filbey ◽  
Joseph Dunlop ◽  
Ariel Ketcherside ◽  
Jessica Baine ◽  
Tyler Rhinehardt ◽  
...  
Keyword(s):  
Fmri Study ◽  
Neural Sensitization

scholarly journals Testing the fast consolidation hypothesis of retrieval-mediated learning

2018 ◽  
Author(s):  
C.S. Ferreira ◽  
I. Charest ◽  
M. Wimber
Keyword(s):  
Testing Effect ◽  
Brain Activity ◽  
Specific Information ◽  
Mediated Learning ◽  
Systems Consolidation ◽  
Fmri Study ◽  
Hippocampal Activity ◽  
Acting Mechanism ◽  
Sleep Consolidation

AbstractThe testing-effect, or retrieval-mediated learning, is one of the most robust effects in memory research. It shows that actively and repeatedly retrieving information, compared to merely restudying it, improves long-term retention. Surprisingly, little is known about the neurocognitive mechanisms underlying this phenomenon. Attempting to fill this gap, a recent framework proposed that retrieval acts as a fast memory consolidation mechanism, stabilizing memories through online reactivation, similar to memory replay during offline (e.g. sleep) consolidation. In this fMRI study, we empirically tested the predictions derived from this framework.We predicted that reactivation during retrieval allows memories to become embedded in neocortex, creating an additional route to access the memory trace and rendering it less hippocampus-dependent. Participants encoded scene-object pairs and either retrieved or restudied the objects over two sessions, two days apart. We analysed univariate and multivariate changes in brain activity specific to retrieval but not restudy, and tested whether the predicted changes occur rapidly within a session, or evolve slowly, across the two days.Results showed that medial prefrontal cortex activation increased across retrieval trials within one session, consistent with a fast consolidation account. Hippocampal activity decreased across sessions, suggesting a slower mechanism. Moreover, Representational Similarity Analyses (RSA) showed that consecutive retrieval attempts strengthen both higher-level semantic and episode-specific information in parietal areas, both across but not within sessions. Our findings suggest that retrieval supports the online creation of a neocortical trace, which becomes increasingly relevant at long delays when hippocampus-dependent episodic details would otherwise have faded.Significance statementRepeated remembering strengthens memories much more so than repeated learning. The aim of this study was to shed light onto the poorly understood neurocognitive underpinnings of retrieval-mediated learning. We tested a novel framework proposing that a memory’s stabilization via retrieval relies on mechanisms akin to those involved in offline systems consolidation. Observing the retrieval-induced neural pattern changes across different timescales, we find that retrieval stabilizes semantic and episodic aspects of the original memories, and produces increases in prefrontal activity and decreases in hippocampal activity that are consistent with the consolidation view, but not necessarily with a fast acting mechanism. Our findings inform cognitive theories of the testing effect, suggesting that retrieval produces its benefits by interacting with hippocampal-neocortical consolidation mechanisms.

scholarly journals An fMRI Study of Neural Activities Associated With Affective Processing Under Long-Term Affective Film Triggering

2021 ◽  
Vol 168 ◽  
pp. S206
Author(s):  
Shuyue Xu ◽  
Gan Huang ◽  
Linling Li ◽  
Li Zhang ◽  
Zhiguo Zhang ◽  
...  
Keyword(s):  
Affective Processing ◽  
Neural Activities ◽  
Fmri Study

An fMRI study of long-term everyday memory using SenseCam

Memory ◽  
2011 ◽  
Vol 19 (7) ◽  
pp. 733-744 ◽  
Author(s):  
F. Milton ◽  
N. Muhlert ◽  
C.R. Butler ◽  
A. Smith ◽  
A. Benattayallah ◽  
...  
Keyword(s):  
Everyday Memory ◽  
Fmri Study

Stability of emotional dysfunctions? A long-term fMRI study in first-episode schizophrenia

2007 ◽  
Vol 41 (11) ◽  
pp. 918-927 ◽  
Author(s):  
Martina Reske ◽  
Thilo Kellermann ◽  
Ute Habel ◽  
N. Jon Shah ◽  
Volker Backes ◽  
...  
Keyword(s):  
First Episode ◽  
Fmri Study ◽  
First Episode Schizophrenia

Androgens Modulate Brain Networks of Empathy in Female-to-Male Transsexuals: An fMRI Study

2011 ◽  
Vol 22 (4) ◽  
pp. 263-277 ◽  
Author(s):  
Zheng Ye ◽  
Robert Kopyciok ◽  
Bahram Mohammadi ◽  
Ulrike M. Krämer ◽  
Claudia Brunnlieb ◽  
...  
Keyword(s):  
Social Relations ◽  
Social Cognitive ◽  
Social Relation ◽  
Inferior Frontal Gyrus ◽  
Hormonal Treatment ◽  
Mental States ◽  
Brain Network ◽  
Left Inferior Frontal Gyrus ◽  
Fmri Study

Women show higher sensitivity than men to emotional and social cues and are therefore better in showing empathy with others and in deciphering other’s intentions and mental states. These sex differences have been linked to hormonal levels. However, it remains unclear how hormones modulate neural mechanisms underlying empathic processes. To assess effects of chronic hormonal treatment, functional magnetic resonance imaging was used in a group of female-to-male transsexuals before and during androgen therapy and a group of female and male controls while they watched pictures portraying emotionally negative or neutral situations (emotional content) involving one or two persons (social relation). Before therapy, the medial superior frontal gyrus and left inferior frontal gyrus showed greater activations for emotional than neutral stimuli. The posterior superior temporal sulcus showed greater activations for emotional vs. neutral stimuli and for social relations relative to pictures of single persons. Long-term androgen administration reduced the pSTS activity in response to emotional stimuli as well as its response to social relation. More importantly, the functional connectivity among frontal, temporal and striatal regions was weakened while the connectivity among limbic regions was strengthened as the androgen level increased during hormone therapy. This pattern of change was similar to the sex difference observed between female vs. male controls. Thus, making a brain more male by the application of androgens not only reduced the activity of a core neural hub but also markedly altered the organization of the brain network supporting emotional and social cognitive processes related to empathy and mentalizing.

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