Personality, dietary identity, mental and sleep health in vegans and vegetarians: A preliminary cross-sectional study.

Background and Aims: Plant-based diets have gained popularity over the past decade. However, research regarding mental and sleep health benefits of following plant-based diets are conflicting. As there are associations between mental/sleep health and various personality traits, and personality may differ between individuals who follow different diets, in this preliminary study, we examined the associations between mental and sleep health and (i) personality and (ii) dietary identity in individuals who follow vegan and vegetarian diets. Methods: Cross-sectional data on sociodemographic, personality traits, dietarian identity, overall mental health, depression, anxiety, stress, and sleep quality were collected from 57 vegan/vegetarian participants between the ages of 18-40. Results: After controlling for various sociodemographic and lifestyle factors, linear regression models revealed that (i) higher dietarian private regard was a significant predictor of better overall mental health, (ii) lower levels of extraversion and higher levels of empathy predicted depression, (iii) higher levels of neuroticism and empathy predicted anxiety, (iv) higher levels of neuroticism, dietarian centrality, and neuroticism × centrality predicted stress, (v) higher levels of conscientiousness, lower levels of dietarian centrality, but higher levels of personal motivation and dietary strictness, as well as conscientiousness × centrality, conscientiousness × personal motivation, and conscientiousness × strictness predicted better sleep quality. Conclusions: These preliminary findings suggest that not only personality traits, but also dietary identity was indeed related to mental and sleep health in individuals who follow plant-based diets.

Déjà vu and the entorhinal cortex: dissociating recollective from familiarity disruptions in a single case patient.

Past research has demonstrated a relationship between déjà vu and the entorhinal cortex in patients with wider medial temporal lobe damage. The aim of the present research was to investigate this crucial link in a patient (MR) with a selective lesion to the left lateral entorhinal cortex to provide a more direct exploration of this relationship. Two experiments investigated the experiences of déjà vécu (using the IDEA questionnaire) and déjà vu (using an adapted DRM paradigm) in MR and a set of matched controls. The results demonstrated that MR had quantitatively more and qualitatively richer recollective experiences of déjà vécu. In addition, under laboratory-based déjà vu conditions designed to elicit both false recollection (critical lures) and false familiarity (weakly-associated lures), MR only revealed greater memory impairments for the latter. The present results are therefore the first to demonstrate a direct relationship between the entorhinal cortex and the experience of both déjà vu and déjà vécu. They furthermore suggest that the entorhinal cortex is involved in both weakly-associative false memory as well as strongly-associative memory under conditions that promote familiarity-based processing.

Left entorhinal cortex and object recognition.

The present research explored the role of the medial temporal lobes in object memory in the unique patient MR, who has a selective lesion to her left lateral entorhinal cortex. Two experiments explored recognition memory for object identity and object location in MR and matched controls. The results showed that MR had intact performance in an object location task [MR=0.70, controls=0.69, t(6)=0.06, P>0.05], but was impaired in an object identity task [MR=0.62, controls=0.84, t(6)=-4.12, P<0.05]. No differences in correct recollection or familiarity emerged. These results suggest a differential role of the entorhinal cortex in object recognition memory. The current research is therefore the first patient study to show the role of the lateral entorhinal cortex in object identity recognition and suggests that current medial temporal lobe theoretical models on both object and recognition memory require a theoretical re-think to account for the contributions of the entorhinal cortex in these processes.

No evidence for age-related differences in item-method directed forgetting of emotional words.

Research indicates that people can intentionally forget, but it is less clear how ageing and emotion interact with this ability. The present research investigated item-method directed forgetting of negative, neutral, and positive words in young (20-35 years), young-old (60-74 years), and old-old (75-89 years) adults. Although old-old adults showed overall reduced memory compared to young and young-old adults, all three age groups showed intentional forgetting. Moreover, intentional forgetting was not affected by the valence of the word in any of the three age groups. These findings suggest that younger and older adults can intentionally forget information that is neutral or emotional in nature. The present study's results extend previous research by showing that this ability is preserved in very old age.

Selective lesion to the entorhinal cortex leads to an impairment in familiarity but not recollection.

The present research explored the effects of selective impairment to the entorhinal cortex on the processes of familiarity and recollection. To achieve this objective, the performance of patient MR, who has a selective impairment of the left entorhinal cortex, was compared to that of age and IQ-matched controls. Four experiments tested participants' recognition memory for familiar and unfamiliar faces and words. In all experiments, participants studied lists of items and then completed an old/new recognition test in which they also made remember/know/guess judgements. A fifth experiment tested participants' priming associated with the familiarity process. MR had intact performance in both face recognition experiments as well as having intact performance in pseudoword recognition. Crucially, however, in the familiar word experiment, whilst MR performed similarly to control participants in terms of recollection, she showed a marked impairment in familiarity. Furthermore, she also demonstrated a reversed conceptual priming effect. MR's impairment is both material-specific and selective for previously encountered but not new verbal items (pseudowords). These findings provide the first clear evidence that selective impairment of the entorhinal cortex impairs the familiarity process for familiar verbal material whilst leaving recollection intact. These results suggest the entorhinal cortex does not have attributes reflective of both recollection and familiarity as previously assumed, but rather supports context-free long-term familiarity-based recognition memory.

Frontal transcranial direct current stimulation (tDCS) abolishes list-method directed forgetting.

It is a point of controversy as to whether directed forgetting effects are a result of active inhibition or a change of context initiated by the instruction to forget. In this study we test the causal role of active inhibition in directed forgetting. By applying cathodal transcranial direct current stimulation (tDCS) over the right prefrontal cortex we suppressed cortical activity commonly associated with inhibitory control. Participants who underwent real brain stimulation before completing the directed forgetting paradigm showed no directed forgetting effects. Conversely, those who underwent sham brain stimulation demonstrated classical directed forgetting effects. We argue that these findings suggest that inhibition is the primary mechanism that results in directed forgetting costs and benefits.

Effects of glucose administration on category exclusion recognition.

Previous research has produced discrepant findings as to whether glucose administration effects lead to enhanced recollection or arise only under dual-task conditions. The aim of the present research was to address these issues by firstly employing an alternative cognitively demanding paradigm that has been linked to hippocampal function, i.e. the Process Dissociation Procedure (PDP). A second aim was to use this paradigm to explore whether glucose affects qualitative aspects of memory function. To achieve these aims, the PDP task was administered to participants who had either consumed a glucose (25 g) or aspartame-sweetened control drink. Results demonstrated glucose facilitation effects only under difficult task conditions and with no such effect emerging for the process of recollection. The present results support the contention that the beneficial effects of glucose arise under hippocampally driven, cognitively demanding task conditions, and that this effect enhances quantitative but not qualitative aspects of recognition memory.

Interaction between mode of learning and subjective experience: translation effects in long-term memory.

It has been suggested that writing auditorily presented words at encoding involves distinctive translation processes between visual and auditory domains, leading to the formation of distinctive memory traces at retrieval. This translation effect leads to higher levels of recognition than the writing of visually presented words, a non-translation effect. The present research investigated whether writing and the other translation effect of vocalisation (vocalising visually presented words) would be present in tests of recall, recognition memory and whether these effects are based on the subjective experience of remembering or knowing. Experiment 1 found a translation effect in the auditory domain in recall, as the translation effect of writing yielded higher recall than both non-translation effects of vocalisation and silently hearing. Experiment 2 found a translation effect in the visual domain in recognition, as the translation effect of vocalisation yielded higher recognition than both non-translation effects of writing and silently reading. This translation effect was attributable to the subjective experience of remembering rather than knowing. The present research therefore demonstrates the beneficial effect of translation in both recall and recognition, with the effect of vocalisation in recognition being based on rich episodic remembering.

Differential facilitative effects of glucose administration on Stroop task conditions.

Previous research has demonstrated that glucose administration improves memory performance. These glucose facilitation effects have been most reliably demonstrated in medial temporal lobe tasks with the greatest effects found for cognitively demanding tasks. The aim of the proposed research was to first explore whether such effects might be demonstrated in a frontal lobe task. A second aim was to investigate whether any beneficial effects of glucose may arise more prominently under tasks of increasing cognitive demand. To achieve these aims, the Stroop Task was administered to participants and effects of a drink of glucose (25 g) were compared with an aspartame-sweetened control drink on performance in young adults. Results demonstrated that glucose ingestion significantly reduced RTs in the congruent and incongruent conditions. No effect on error rates was observed. Of most importance was the finding that this glucose facilitative effect was significantly greatest in the most cognitively demanding task, that is, the incongruent condition. The present results support the contention that the glucose facilitation effect is most robust under conditions of enhanced task difficulty and demonstrate that such benefits extend to frontal lobe function.

Forgetting emotional and neutral words: an ERP study.

Previous research has demonstrated that emotional material is more likely to be remembered than neutral material (Hamann, 2001). The present study employed the item-method of directed forgetting in order to examine whether emotionally negative words are not only easier to remember, but also harder to forget. Event-related potentials (ERPs) were additionally measured in order to investigate the processes of selective rehearsal and active inhibition in directed forgetting. The results demonstrated directed forgetting effects for both neutral and negative words, with a stronger effect for negative items. Late positive potentials (LPPs) for 'to-be-remembered' (TBR) relative to 'to-be-forgotten' (TBF) cues were enhanced when the cues followed negative in comparison to neutral words, indicating the greater selective rehearsal of TBR negative items. Frontal positivities to TBF relative to TBR cues were not modulated by word valence, indicating that inhibitory processes were unaffected by emotion. Taken together, the present research demonstrates for the first time that, not only are emotionally negative words prone to the same directed forgetting effects as neutral words, but that these effects are in fact enhanced for negative words and due to increased selective rehearsal of TBR negative items. The discrepancies between the present findings and those of previous studies are discussed.

Student-created scenarios in the high-fidelity simulation laboratory.

As an assignment in a pediatric theory class, small groups of nursing students created and implemented scenarios in the high-fidelity simulation (HFS) laboratory. The project's purpose was to determine whether senior nursing students could create HFS scenarios that increased their knowledge base of pediatric nursing and supported the use of evidence in identifying problems and planning nursing care. After completing the project, students wrote individual reflective papers. Qualitative analysis of these papers revealed the common themes of expanded understanding of pediatric nursing care and professional growth. Data supported achievement of the project objectives; however, this was attributed to the scenario-creation process rather than to the scenarios themselves. Challenges identified included lack of a mechanism to involve each student in every scenario and logistical issues, such as faculty time and laboratory scheduling. With attention to such issues, this project can be implemented successfully in a variety of clinical areas.

The effects of glucose dose and dual-task performance on memory for emotional material.

Whilst previous research has shown that glucose administration can boost memory performance, research investigating the effects of glucose on memory for emotional material has produced mixed findings. Whereas some research has shown that glucose impairs memory for emotional material, other research has shown that glucose has no effect on emotional items. The aim of the present research was therefore to provide further investigation of the role of glucose on the recognition of words with emotional valence by exploring effects of dose and dual-task performance, both of which affect glucose facilitation effects. The results replicated past research in showing that glucose administration, regardless of dose or dual-task conditions, did not affect the memorial advantage enjoyed by emotional material. This therefore suggests an independent relationship between blood glucose levels and memory for emotional material.

Impairment of recollection but not familiarity in a case of developmental amnesia.

In a re-examination of the recognition memory of Jon, a young adult with developmental amnesia due to perinatal hippocampal damage, we used a test procedure that provides estimates of the separate contributions to recognition of recollection and familiarity. Comparison between Jon and his controls revealed that, whereas he was unimpaired in the familiarity process, he showed abnormally low levels of recollection, supporting the view that the hippocampus mediates the latter process selectively.

Charting the acquisition of semantic knowledge in a case of developmental amnesia.

We report the acquisition and recall of novel facts by Jon, a young adult with early onset developmental amnesia whose episodic memory is gravely impaired due to selective bilateral hippocampal damage. Jon succeeded in learning some novel facts but compared with a control group his intertrial retention was impaired during acquisition and, except for the most frequently repeated facts, he was also less accurate in correctly sourcing these facts to the experiment. The results further support the hypothesis that despite a severely compromised episodic memory and hippocampal system, there is nevertheless the capacity to accrue semantic knowledge available to recall.

Reinstating effortful encoding operations at test enhances episodic remembering.

Two experiments investigated the effects of reinstating encoding operations on remember and know responses in recognition memory. Experiment 1 showed that reinstating an effortful encoding task (generating words from fragments) increased remember responses at test but reinstating an automatic encoding task (reading intact words) did not. This pattern was confirmed in Experiment 2 in which words were either read intact or generated from anagrams. These findings show that repeating effortful (but not automatic) encoding operations at test cues not only the recognition of the information that was acquired via those operations but also the conscious recollection of the encoding episode.

Using semantic memory to boost 'episodic' recall in a case of developmental amnesia.

We report two experiments that investigated factors that might boost 'episodic' recall for Jon, a developmental amnesic whose episodic memory is gravely impaired but whose semantic memory seems relatively normal. Experiment 1 showed that Jon's recall improved following a semantic study task compared with a non-semantic study task, as well as following four repeated study trials compared with only one. Experiment 2 additionally revealed that Jon's recall improved after acting compared with reading action phrases at study, but only if the phrases were well integrated semantically. The results provide some support for the hypothesis that Jon's 'episodic' recall depends on the extent to which he is able to retrieve events using semantic memory.

The effect of glucose administration on the emotional enhancement effect in recognition memory.

Previous research has demonstrated that glucose administration improves memory performance. However few studies have addressed the effects of glucose on emotional material that by nature already enjoys a memory advantage. The aim of the present research was therefore to investigate whether the memory facilitation effect associated with glucose would emerge for emotional words. Experiment 1 demonstrated that negative words were better recognized and remembered than positive and neutral words. Experiment 2 further explored these effects under conditions of glucose administration and an aspartame control. The results revealed that both the aspartame and glucose groups replicated the results from Experiment 1. The present research therefore demonstrated that the glucose facilitation effect did not emerge for material that already benefits from a memory advantage. These results also raise the question of whether the dose response relationship previously associated with glucose administration is applicable when the information being processed is of an emotional nature.

The distinctiveness effect in forenames: the role of subjective experiences and recognition memory.

We describe two experiments that tested the prediction that distinctive forenames would be better recognized than typical forenames and which investigated whether this distinctiveness effect, if obtained, occurred in subjective experiences of the recollective or familiarity components of recognition memory. To that end, the remember-know paradigm was used to measure people's experiences of recollection or familiarity. The results revealed that distinctive forenames were more memorable than typical forenames and that that this distinctiveness effect was present only in the subjective experience of remembering. Additionally, the present research showed that these distinctiveness effects were present after retention intervals of both 1 and 7 days. These results replicate and extend past research on distinctiveness effects and also provide support for Rajaram's (1996) distinctiveness-fluency account of the 2 states of subjective awareness.

Measuring the speed of the conscious components of recognition memory: remembering is faster than knowing.

Three experiments investigated response times (RTs) for remember and know responses in recognition memory. RTs to remember responses were faster than RTs to know responses, regardless of whether the remember-know decision was preceded by an old/new decision (two-step procedure) or was made without a preceding old/new decision (one-step procedure). The finding of faster RTs for R responses was also found when remember-know decisions were made retrospectively. These findings are inconsistent with dual-process models of recognition memory, which predict that recollection is slower and more effortful than familiarity. Word frequency did not influence RTs, but remember responses were faster for words than for nonwords. We argue that the difference in RTs to remember and know responses reflects the time taken to make old/new decisions on the basis of the type of information activated at test.