Recognition memory and prefrontal cortex: dissociating recollection and familiarity processes using rTMS

Recognition memory can be supported by both the assessment of the familiarity of an item and by the recollection of the context in which an item was encountered. The neural substrates of these memory processes are controversial. To address these issues we applied repetitive transcranial magnetic stimulation (rTMS) over the right and left dorsolateral prefrontal cortex (DLPFC) of healthy subjects performing a remember/know task. rTMS disrupted familiarity judgments when applied before encoding of stimuli over both right and left DLPFC. rTMS disrupted recollection when applied before encoding of stimuli over the right DLPFC. These findings suggest that the DLPFC plays a critical role in recognition memory based on familiarity as well as recollection.     

Focusing effects in predecisional information acquisition

Legrenzi et al. [Legrenzi, P., Girotto, V., & Johnson-Laird, P. N. (1993). Focusing in reasoning and decision making. Cognition, 49, 37-66] showed that when a single option is proposed for consideration the decision makers limit their information acquisition to this one option, failing to take into account potential alternatives. Unfortunately, the evidence supporting this focusing effect is weak and its determinants are largely unknown. In three experiments, we provided stronger support for the reality of the focusing effect and we identified two significant determinants of this phenomenon. The results show that both representational and value-related manipulations are able to reduce the effect. Results also suggest the need to distinguish between two different types of focusing: representational focusing and search-related focusing.     

Saccade-stepping interactions revise the motor plan for obstacle avoidance

The authors used a stimulus-response compatibility paradigm to assess the effect of changing the estimated time to obstacle contact. A limb-selection cue was presented in different phases of gait to young (n = 5) and to older (n = 4) adults while they were moving toward a foam obstacle in the walking path. A downward saccade was initiated after the cue; the saccade typically occurred during the stance phase of the target limb (the foot cued to lead the step over the obstacle). The mean saccade-step latency after the cue was on the order of -500 ms in both young and elderly participants. On reaching the obstacle, both groups generated an upward saccade approximately -300 ms before target footlift in both groups. Saccades following the limb-selection cue appeared to direct the gaze toward footfall targets just beyond the obstacle, whereas saccades generated just before obstacle footlift moved the gaze to the forward-looking direction. The elderly had significantly longer saccade-trailing-footlift latencies and prolonged gaze-fixation times than did the younger adults. Transient disruptions in optical flow appeared to be necessary for successful obstacle-avoidance behavior when there was an unexpected change in the estimated time to obstacle contact.     

CS-dependent response probability in an auditory masked-detection task: considerations based on models of Pavlovian conditioning.

Experimental studies were performed using a Pavlovian-conditioned eyeblink response to measure detection of a variable-sound-level tone (T) in a fixed-sound-level masking noise (N) in rabbits. Results showed an increase in the asymptotic probability of conditioned responses (CRs) to the reinforced TN trials and a decrease in the asymptotic rate of eyeblink responses to the non-reinforced N presentations as a function of the sound level of the T. These observations are consistent with expected behaviour in an auditory masked detection task, but they are not consistent with predictions from a traditional application of the Rescorla-Wagner or Pearce models of associative learning. To implement these models, one typically considers only the actual stimuli and reinforcement on each trial. We found that by considering perceptual interactions and concepts from signal detection theory, these models could predict the CS dependence on the sound level of the T. In these alternative implementations, the animals response probabilities were used as a guide in making assumptions about the "effective stimuli".     

The ecological validity of the “who said what?” technique: An examination of the role of self‐involvement,cognitive interference and acquaintanceship

Questions are raised about the possible ecological invalidity of the traditional “who said what?” (WSW) procedure. Three studies are reported which use a modified, quasi‐naturalistic version of the WSW technique, in which rather than being passive recipients of presented information, participants instead play an active role in the production of such information in an interactive context. Data are presented that demonstrate that the social categorization effect typically obtained through the traditional WSW procedure generalizes beyond the circumstances in which it was initially demonstrated. Thus, in Study 1 it was established that social categories (gender, in this case) are cognitively used in real interactions between participants in order to organize information. Moreover, Study 2 demonstrated that the use of categories is accentuated when, as is typical in real world situations, recollections are not made immediately after the perception of the relevant stimuli but following a period of intervening cognitive activity. The findings of Study 3, however, suggest that the WSW technique may not inevitably lead to social categorization effects: typical effects did not appear when participants knew each other well, and therefore saw one another as unique, idiosyncratic individuals, rather than as category members.     

Incremental variance in indecisiveness due to cognitive failure compared to fluid intelligence and personality traits

This study investigated the role of fluid intelligence, personality traits and perceived cognitive failure in relation to indecisiveness. The Advanced Progressive Matrices (APM), the Big Five Questionnaire (BFQ) and the Cognitive Failures Questionnaire (CFQ) were administered to 429 Italian high school students. The study revealed that perceived cognitive failure added a significant percentage of incremental variance in indecisiveness compared to variances due to fluid intelligence and personality traits thereby offering new research and intervention possibilities.     

Age Differences in Multiple Outcome Measures of Time-Based Prospective Memory

ABSTRACT

This study examined time-based prospective memory performance in relation to age, monitoring strategy, response accuracy, and dual-task demands. Young, middle-aged and older adults (N?=?115) completed a prospective memory task, in which they indicated the passing of time every 5 min while listening to a short story (low task demands) or completing a series of cognitive tasks (high task demands). Young and older adults showed similar patterns of monitoring behavior, with low rates of clock checking during the early phase of each 5-min interval, followed by linearly accelerating monitoring functions. However, to obtain the same level of prospective memory performance older adults needed more frequent clock checks than young adults. Furthermore, older adults' compensatory monitoring strategy was associated with an additional cost in primary task performance. Finally, increased primary task demands shifted age differences in prospective memory from monitoring frequency to response accuracy. These findings suggest that goal-directed behavior requires efficient task coordination and resource allocation, and that age-related differences in time-based prospective memory should be evaluated by using multiple outcome measures.     

Gait and risk of falls associated with frontal cognitive functions at different stages of Alzheimer's disease

ABSTRACT

The decline in frontal cognitive functions contributes to alterations of gait and increases the risk of falls in patients with dementia, a category which included Alzheimer's disease (AD). The objective of the present study was to compare the gait parameters and the risk of falls among patients at different stages of AD, and to relate these variables with cognitive functions. This is a cross-sectional study with 23 patients with mild and moderate AD. The Clinical Dementia Rating was used to classify the dementia severity. The kinematic parameters of gait (cadence, stride length, and stride speed) were analyzed under two conditions: (a) single task (free gait) and (b) dual task (walking and counting down). The risk of falls was evaluated using the Timed Up-and-Go test. The frontal cognitive functions were evaluated using the Frontal Assessment Battery (FAB), the Clock Drawing Test (CDT) and the Symbol Search Subtest. The patients who were at the moderate stage suffered reduced performance in their stride length and stride speed in the single task and had made more counting errors in the dual task and still had a higher fall risk. Both the mild and the moderate patients exhibited significant decreases in stride length, stride speed and cadence in the dual task. Was detected a significant correlation between CDT, FAB, and stride speed in the dual task condition. We also found a significant correlation between subtest Similarities, FAB and cadence in the dual task condition. The dual task produced changes in the kinematic parameters of gait for the mild and moderate AD patients and the gait alterations are related to frontal cognitive functions, particularly executive functions.     

Effectiveness of the career interest profile

This study examined the effectiveness of group‐based career counseling using the Career Interest Profile (CIP). The study used an experimental design involving 2 groups of Italian university students: an experimental group (42 participants) who received narrative career counseling and a control group (47 participants) who did not. Results indicated more specific life and occupational goals after the intervention among members of the experimental group in addition to a decrease in career decision‐making difficulties and an increase in career decision‐making self‐efficacy, thus suggesting the value of group‐based career counseling on the basis of the principles embodied in the CIP.