An fMRI study on memory discriminability for complex visual scenes

Abstract

The fan effect represents an increase in reaction time for the recognition of an item as a function of the amount of information associated with that item in memory. The present study used fMRI to study the neural correlates of the fan effect for complex visual scenes. We used a test in which landscape pictures were divided vertically into three equal segments. In the high discriminability condition only one segment was presented during encoding, whereas in the low discriminability condition two different segments from the same picture were presented. During a subsequent forced-choice recognition test, reaction times were significantly faster for the high discriminability condition. Increase in brain activity for the low relative to high discriminability condition was observed in the right prefrontal cortex, several regions of parietal cortex bilaterally, and several late visual processing areas, including the occipito-temporal regions, precuneus, and cuneus. These results support the hypothesis that a region of the prefrontal cortex is involved in the control of memory interference at retrieval elicited by the amount of related information in memory, and further suggests that this involvement is right-lateralized for nonverbal material. The high versus low discriminability contrast showed an increase in activity principally in the bilateral medial temporal gyrus, including the enthorinal cortex/hippocampus and in several bilateral prefrontal cortex regions mostly located in BA 10. These activations were associated with a condition, in which the stimuli were more salient in memory and thus could represent the perceptual salience of items in memory.

Comparison of Associative Learning-Related Signals in the Macaque Perirhinal Cortex and Hippocampus

“…In the current experiment we used complex scene stimuli including both outdoor scenes as well as scenes of animals. The visual scene stimuli in particular have been shown to be highly effective at engaging the hippocampus in humans (Stern et al 1996;Hartley et al 2007;Blondin and Lepage 2007). Using these stimuli, we report that 90% of the hippocampal cells were responsive to the location-scene task and 73% of those responsive cells were selective.…”

Neural processing of criticism and positive comments from relatives in individuals with schizotypal personality traits

“…Reduced activation of the right lingual gyrus and cuneus during criticism relative to neutral comments may suggest lesser use during criticism of autobiographical (Burianova and Grady 2007) and visual memory (Blondin and Lepage 2008), recognition of facial affect (Kitada et al 2010) and verbal affect (Rama et al 2001), as well as lesser use of mental imagery during affect recognition (Kim et al 2007) that are normally associated with these brain regions. During neutral comments which consisted of describing the participant ' s general day-to-day activities (see Supplementary text available online), such as going shopping, as well as specifi c recent activities, such as going on holiday, information may be processed in a relatively non-affective way, such as recollection of gyrus, another cluster located in the left claustrum, extending to the putamen and subthalamic nucleus of the brain stem, a cluster located in the right inferior occipital gyrus, extending to the right lingual gyrus and right fusiform gyrus, a cluster in the right thalamus and right insula, and clusters in the right precentral gyrus and right medial frontal gyrus, extending to the middle frontal gyrus (Table V and Figure 1).…”

Hippocampal Estrogen Signaling Mediates Sex Differences in Retroactive Interference

“…Specifically, several works have tried to conceptualize a theoretical framework for interference-mediated forgetting [ 2 ] and attempted to dissect the physiological variables and molecular mechanisms underlying forgetting and interference dynamics [ 5 ]. At the circuit level, interference involves multiple brain regions that are necessary for memory storage and retrieval [ 6 , 7 , 8 ]. It has been shown that, in the novel object recognition (NOR) paradigm, exposure to an interference session during the consolidation phase leads to memory loss, and this effect is dependent on medial prefrontal cortex and hippocampal activity [ 9 , 10 ].…”