Consolidation and long-term retention of an implanted behavioral memory

Hypothesized circuitry enabling information storage can be tested by attempting to implant memory directly in the brain in the absence of normal experience. Previously, we found that tone paired with activation of the cholinergic nucleus basalis (NB) does induce behavioral memory that shares cardinal features with natural memory; it is associative, highly specific, rapidly formed, consolidates and shows intermediate retention. Here we determine if implanted memory also exhibits long-term consolidation and retention. Adult male rats were first tested for behavioral responses (disruption of ongoing respiration) to tones (1-15 kHz), yielding pre-training behavioral frequency generalization gradients. They next received 3 days of training with a conditioned stimulus (CS) tone (8.0 kHz, 70 dB, 2s) either paired (n=7) or unpaired (n=6) with moderate electrical stimulation of the nucleus basalis (～ 65 μA, 100 Hz, 0.2s, co-terminating with CS offset). Testing for long-term retention was performed by obtaining post-training behavioral frequency generalization gradients 24h and 2 weeks after training. At 24h post-training, the Paired group exhibited specific associative behavioral memory, manifested by larger responses to the CS frequency band than the Unpaired group. This memory was retained 2 weeks post-training. Moreover, 2 weeks later, the specificity and magnitude of memory had become greater, indicating that the implanted memory had undergone consolidation. Overall, the results demonstrate the validity of NB-implanted memory for understanding natural memory and that activation of the cholinergic nucleus basalis is sufficient to form natural associative memory.     

The role of overt attention in emotion-modulated memory

The presence of emotional stimuli results in a central/peripheral tradeoff effect in memory: memory for central details is enhanced at the cost of peripheral items. It has been assumed that emotion-modulated differences in memory are the result of differences in attention, but this has not been tested directly. The present experiment used eye movement monitoring as an index of overt attention allocation and mediation analysis to determine whether differences in attention were related to subsequent memory. Participants viewed negative and neutral scenes surrounded by three neutral objects and were then given a recognition memory test. The results revealed evidence in support of a central/peripheral tradeoff in both attention and memory. However, contrary with previous assumptions, whereas attention partially mediated emotion-enhanced memory for central pictures, it did not explain the entire relationship. Further, although centrally presented emotional stimuli led to decreased number of eye fixations toward the periphery, these differences in viewing did not contribute to emotion-impaired memory for specific details pertaining to the periphery. These findings suggest that the differential influence of negative emotion on central versus peripheral memory may result from other cognitive influences in addition to overt visual attention or on postencoding processes.     

A Priestly Approach to Environmental Theology: Learning to Receive and Give Again the Gifts of Creation

Abstract : A priestly sensibility is here presented as a way to characterize humanity's place in creation. Sacrifice, asceticism, and gratitude are described as three distinct and practical modalities of a priestly life that contribute to the care and celebration of creation. While a priestly understanding is often associated with Orthodox environmental theology, it has the potential to inform environmental theology broadly construed.     

Measuring “intuition” in the SRT generation task

We address some concerns related to the use of post-trial attribution judgments, originally developed for artificial grammar learning (AGL), during the version of the serial reaction time (SRT) task used by Fu, Dienes, and Fu (2010). In particular, intuition attributions, which are central to Fu et al.’s arguments, seem problematic: This attribution is likely to be made when stimuli contain several competing sources of information to which subjective feelings could be attributed. The interpretation of intuition attributions in Fu et al.’s SRT generation task is problematic because the procedure involved a 2-element sequence where items varied only in position. In our view, responses categorised as intuitions might have been a variety of guess response where neither judgement knowledge nor structural knowledge were conscious. The results would then be compatible with previous findings showing that people can control the use of unconscious structural knowledge even when judgement knowledge is unconscious.     

The roles of ingroup identification and outgroup entitativity in intergroup retribution

A new aspect of intergroup conflict was investigated- vicarious retribution-in which neither the agent of retribution nor the target of retribution are directly involved in the initial intergroup provocation. The underlying processes involved in vicarious intergroup retribution were tested correlationally (Study 1) and experimentally (Study 2). Both ingroup identification and outgroup entitativity predict the degree of vicarious retribution. In both studies, there was evidence of motivated cognition, specifically that highly identified individuals perceived the outgroup as higher in entitativity than individuals low in identification. Structural equation modeling demonstrated that part of the effect of identification on retribution against the outgroup was mediated through perceptions of entitativity.     

Learning to perceive differences in solid shape through vision and touch

A single experiment was designed to investigate perceptual learning and the discrimination of 3-D object shape. Ninety-six observers were presented with naturally shaped solid objects either visually, haptically, or across the modalities of vision and touch. The observers' task was to judge whether the two sequentially presented objects on any given trial possessed the same or different 3-D shapes. The results of the experiment revealed that significant perceptual learning occurred in all modality conditions, both unimodal and cross-modal. The amount of the observers' perceptual learning, as indexed by increases in hit rate and d', was similar for all of the modality conditions. The observers' hit rates were highest for the unimodal conditions and lowest in the cross-modal conditions. Lengthening the inter-stimulus interval from 3 to 15 s led to increases in hit rates and decreases in response bias. The results also revealed the existence of an asymmetry between two otherwise equivalent cross-modal conditions: in particular, the observers' perceptual sensitivity was higher for the vision-haptic condition and lower for the haptic-vision condition. In general, the results indicate that effective cross-modal shape comparisons can be made between the modalities of vision and active touch, but that complete information transfer does not occur.     

Flexible and inflexible response components: a Stroop study with typewritten output

Two experiments were directed at investigating the relationship between response selection and execution in typewriting, and specifically the extent to which concurrent processing takes place. In a Stroop paradigm adapted from [Logan, G. D., & Zbrodoff, N. J. (1998). Stroop-type interference: Congruity effects in colour naming with typewritten responses. Journal of Experimental Psychology: Human Perception and Performance, 24, 978–992], participants typed the names of colour patches with incongruent, congruent, or neutral distractors presented at various stimulus-onset asynchronies. Experiment 1 showed Stroop interference and facilitation for initial keystroke latencies and errors, contrasting with response durations (a measure of response execution) being unaffected by Stroop manipulation. Experiment 2 showed that all three measures were responsive to time pressure; again, Stroop effects were confined to latencies and errors only. The observation that response duration is both flexible under time pressure and protected from response competition, may imply either that response execution is structurally segregated from earlier processing stages, or that encapsulation develops during the acquisition of typing skills.