Protention and retention in biological systems

This paper proposes an abstract mathematical frame for describing some features of cognitive and biological time. We focus here on the so called "extended present" as a result of protentional and retentional activities (memory and anticipation). Memory, as retention, is treated in some physical theories (relaxation phenomena, which will inspire our approach), while protention (or anticipation) seems outside the scope of physics. We then suggest a simple functional representation of biological protention. This allows us to introduce the abstract notion of "biological inertia".Comment: This paper was made possible only as part of an extended collaboration with Francis Bailly (see references), a dear friend and "ma\^itre \'a penser", who contributed to the key ideas. Francis passed away in february 2008: we continue here our inspiring discussions and joint wor

Front Aging Neurosci

We studied the influence of emotions on autobiographical memory (AbM) in patients with Alzheimer's disease (AD), characteristically triggering atrophy in the hippocampus and the amygdala, two crucial structures sustaining memory and emotional processing. Our first aim was to analyze the influence of emotion on AbM in AD patients, on both the proportion and the specificity of emotional memories. Additionally, we sought to determine the relationship of emotional AbM to amygdalar-hippocampal volumes. Eighteen prodromal to mild AD patients and 18 age-matched healthy controls were included. We obtained 30 autobiographical memories per participant using the modified Crovitz test (MCT). Analyses were performed on global scores, rates and specificity scores of the emotional vs. neutral categories of memories. Amygdalar-hippocampal volumes were extracted from 3D T1-weighted MRI scans and tested for correlations with behavioral data. Overall, AD patients displayed a deficit in emotional AbMs as they elicited less emotional memories than the controls, however, the specificity of those memories was preserved. The deficit likely implied retrieval or storage as it was extended in time and without reminiscence bump effect. Global scores and rates of emotional memories, but not the specificity scores, were correlated to right amygdalar and hippocampal volumes, indicating that atrophy in these structures has a central role in the deficit observed. Conversely, emotional memories were more specific than neutral memories in both groups, reflecting an enhancement effect of emotion that could be supported by other brain regions that are spared during the early stages of the disease

Re-imagining the future:repetition decreases hippocampal involvement in future simulation

Imagining or simulating future events has been shown to activate the anterior right hippocampus (RHC) more than remembering past events does. One fundamental difference between simulation and memory is that imagining future scenarios requires a more extensive constructive process than remembering past experiences does. Indeed, studies in which this constructive element is reduced or eliminated by “pre-imagining” events in a prior session do not report differential RHC activity during simulation. In this fMRI study, we examined the effects of repeatedly simulating an event on neural activity. During scanning, participants imagined 60 future events; each event was simulated three times. Activation in the RHC showed a significant linear decrease across repetitions, as did other neural regions typically associated with simulation. Importantly, such decreases in activation could not be explained by non-specific linear time-dependent effects, with no reductions in activity evident for the control task across similar time intervals. Moreover, the anterior RHC exhibited significant functional connectivity with the whole-brain network during the first, but not second and third simulations of future events. There was also evidence of a linear increase in activity across repetitions in right ventral precuneus, right posterior cingulate and left anterior prefrontal cortex, which may reflect source recognition and retrieval of internally generated contextual details. Overall, our findings demonstrate that repeatedly imagining future events has a decremental effect on activation of the hippocampus and many other regions engaged by the initial construction of the simulation, possibly reflecting the decreasing novelty of simulations across repetitions, and therefore is an important consideration in the design of future studies examining simulation

Autobiographical thinking interferes with episodic memory consolidation

New episodic memories are retained better if learning is followed by a few minutes of wakeful rest than by the encoding of novel external information. Novel encoding is said to interfere with the consolidation of recently acquired episodic memories. Here we report four experiments in which we examined whether autobiographical thinking, i.e. an 'internal' memory activity, also interferes with episodic memory consolidation. Participants were presented with three wordlists consisting of common nouns; one list was followed by wakeful rest, one by novel picture encoding and one by autobiographical retrieval/future imagination, cued by concrete sounds. Both novel encoding and autobiographical retrieval/future imagination lowered wordlist retention significantly. Follow-up experiments demonstrated that the interference by our cued autobiographical retrieval/future imagination delay condition could not be accounted for by the sound cues alone or by executive retrieval processes. Moreover, our results demonstrated evidence of a temporal gradient of interference across experiments. Thus, we propose that rich autobiographical retrieval/future imagination hampers the consolidation of recently acquired episodic memories and that such interference is particularly likely in the presence of external concrete cues

Contribution de la conscience phonologique et de la mémoire de travail aux difficultés en lecture : étude auprès d'enfants dyslexiques et apprentis lecteurs

Summary : The contribution of phonological awareness and working memory to reading disabilities : A longitudinal study of dyslexics and beginning readers A follow-up study investigated the contribution of phonological awareness and two working memory systems (the articulatory loop and central executive) to reading disabilities. During the first session, dyslexies were matched to the reading level of first-grade children. The study focused on two issues. First, to examine the efficiency of children's capacity to treat phonological components and their working memory. Second, to investigate the way in which the treatment of phonological components skills and working memory are related to later reading achievement. Our goal was to study whether they contribute in the same or separate ways to the variance in reading performance. In general, dyslexics have important and persistent difficulties with the explicit representation of phonological information and thus with recoding skills. Our results are consistent with the hypothesis of a specific deficit hypothesis in the development of phonological skills by dyslexics. Thereby, difficulties with phonological representation appear to be at the core of reading disabilities. Furthermore, fixed-order regression analyses showed that phonological awareness is the most efficient predictor of later recoding achievement, and working memory that of comprehension abilities. Key words : developmental dyslexia, reading, phonological awareness, working memory, articulatory loop, central executive.Résumé Une étude longitudinale sur deux ans est réalisée afin d'étudier la contribution de la conscience phonologique et des deux composants de la mémoire de travail (boucle articulatoire et processeur central) aux performances en lecture d'enfants dyslexiques appariés lors de la première évaluation sur l'âge lexique à des enfants apprentis-lecteurs. L'étude a un double objectif. Le premier est de déterminer l'efficience des enfants dans le traitement des composants phonologiques et leur mémoire de travail et d'étudier le développement des mécanismes impliqués dans l'apprentissage de la lecture et ses difficultés. Le deuxième objectif concerne la manière dont les habiletés de traitement des composants phonologiques et la mémoire de travail sont reliées à l'efficience ultérieure en lecture. Il s'agit plus particulièrement de déterminer si elles contribuent de manière spécifique à la variance dans les performances en lecture. De façon générale, les enfants dyslexiques témoignent de difficultés importantes et persistantes avec la représentation explicite de l'information phonologique et de manière corollaire avec les habiletés en identification de mots. Nos résultats s'avèrent ainsi consistants avec l'hypothèse d'un déficit spécifique dans le développement des habiletés phonologiques chez les enfants dyslexiques. Ainsi, un déficit général dans le traitement phonologique est à la base des difficultés en lecture des dyslexiques. Par ailleurs, les analyses de régression à ordre fixé ont montré que la conscience phonologique est le meilleur prédicteur des habiletés ultérieures en identification de mots et la mémoire de travail le meilleur prédicteur des habiletés en compréhension. Mots-clés : dyslexie développementale, lecture, conscience phonologique, mémoire de travail, boucle articulatoire, processeur central.Demont Elisabeth, Botzung A. Contribution de la conscience phonologique et de la mémoire de travail aux difficultés en lecture : étude auprès d'enfants dyslexiques et apprentis lecteurs. In: L'année psychologique. 2003 vol. 103, n°3. pp. 377-409

Mental hoop diaries: emotional memories of a college basketball game in rival fans.

The rivalry between the men's basketball teams of Duke University and the University of North Carolina-Chapel Hill (UNC) is one of the most storied traditions in college sports. A subculture of students at each university form social bonds with fellow fans, develop expertise in college basketball rules, team statistics, and individual players, and self-identify as a member of a fan group. The present study capitalized on the high personal investment of these fans and the strong affective tenor of a Duke-UNC basketball game to examine the neural correlates of emotional memory retrieval for a complex sporting event. Male fans watched a competitive, archived game in a social setting. During a subsequent functional magnetic resonance imaging session, participants viewed video clips depicting individual plays of the game that ended with the ball being released toward the basket. For each play, participants recalled whether or not the shot went into the basket. Hemodynamic signal changes time locked to correct memory decisions were analyzed as a function of emotional intensity and valence, according to the fan's perspective. Results showed intensity-modulated retrieval activity in midline cortical structures, sensorimotor cortex, the striatum, and the medial temporal lobe, including the amygdala. Positively valent memories specifically recruited processing in dorsal frontoparietal regions, and additional activity in the insula and medial temporal lobe for positively valent shots recalled with high confidence. This novel paradigm reveals how brain regions implicated in emotion, memory retrieval, visuomotor imagery, and social cognition contribute to the recollection of specific plays in the mind of a sports fan