Fourth Blocks Research Articles

Using VGG Models with Intermediate Layer Feature Maps for Static Hand Gesture Recognition

A hand gesture recognition system provides a robust and innovative solution to nonverbal communication through human–computer interaction. Deep learning models have excellent potential for usage in recognition applications. To overcome related issues, most previous studies have proposed new model architectures or have fine-tuned pre-trained models. Furthermore, these studies relied on one standard dataset for both training and testing. Thus, the accuracy of these studies is reasonable. Unlike these works, the current study investigates two deep learning models with intermediate layers to recognize static hand gesture images. Both models were tested on different datasets, adjusted to suit the dataset, and then trained under different methods. First, the models were initialized with random weights and trained from scratch. Afterward, the pre-trained models were examined as feature extractors. Finally, the pre-trained models were fine-tuned with intermediate layers. Fine-tuning was conducted on three levels: the fifth, fourth, and third blocks, respectively. The models were evaluated through recognition experiments using hand gesture images in the Arabic sign language acquired under different conditions. This study also provides a new hand gesture image dataset used in these experiments, plus two other datasets. The experimental results indicated that the proposed models can be used with intermediate layers to recognize hand gesture images. Furthermore, the analysis of the results showed that fine-tuning the fifth and fourth blocks of these two models achieved the best accuracy results. In particular, the testing accuracies on the three datasets were 96.51%, 72.65%, and 55.62% when fine-tuning the fourth block and 96.50%, 67.03%, and 61.09% when fine-tuning the fifth block for the first model. The testing accuracy for the second model showed approximately similar results.

The relationship between ensemble representations of facial information

People accurately evaluate various types of facial information (gaze direction, facial expression, facial identity, and gender) of multiple faces. Considering such varieties, summarizing abilities of facial information might vary depending on its type because it is either changeable (e.g., gaze direction and expression) or invariant (e.g., identity and gender). The current study investigated the relationship between the averaging abilities of facial information using an individual difference approach and a dual-task paradigm to understand the effect of facial information type on the ensemble coding of facial information. We conducted two online experiments on the relationship between the averaging abilities of facial expressions and gaze direction (Experiment 1) and those of facial expressions and gender (Experiment 2). Participants were asked to estimate the average of each piece of facial information in the first and second blocks (single task), respectively, and both sequentially in the third and fourth blocks (dual task). We found that most of the error autocorrelations of facial information were high, indicating high measurement reliability. Participants’ abilities to average facial expressions were correlated with those to average gaze directions, but not with those to average gender information. That is, the ensemble processing of facial expressions is related to gaze directions, but not genders. These results suggest that ensemble representations of facial information regarding changeable properties differ from those of invariant ones.

Examining Different Foci of Attention on Golf Putting Performance in Novice Learners

Although research has leaned toward an external focus, there is no consensus on the optimal distance of the attentional focus for novice learners. The purpose of this study was to examine which type of attentional focus is beneficial for the novices performing golf putting task. Forty-five novice learners (23 males, 22 females), aged 20 to 37, participated in this study. Participants were randomized into the attentional focus of attention (FOA) conditions of internal (i.e., focus on the arm movement), external-proximal (i.e., focus on the golf club), and external-distal (i.e., focus on the target). Each participant was requested to perform four blocks of 10 putts on an artificial putting surface. The total number of putts made, total putt points achieved, and perceived confidence for each putt were recorded. A 4 (block) × 3 (condition) mixed-design analysis of variance was applied for data analysis. The external-proximal FOA condition had significantly better performance (i.e., more putt points) than the external-distal FOA condition. Under the internal FOA condition, participants significantly made more golf putt points during the third and fourth blocks than the first block. Perceived confidence was significantly elevated during the third block and fourth block compared to the first block across all conditions. Postexperimental manipulation check showed most participants adopted the focus as they were instructed. The external-distal FOA may be detrimental for novice learners in skill acquisition. Putting performance was related to the perceived confidence for the golf stroke. Therefore, it is recommended that practitioners consider the OPTIMAL theory by facilitating external-proximal FOA and the motivational factor together for novice learners.

Unintentional force drifts across the human fingers: implications for the neural control of finger tasks.

We explored the unintentional force drift across the four fingers of the dominant hand during accurate force production in isometric conditions caused by turning the visual feedback on force off. Our hypotheses were that the Index finger would show smallest drifts and best ability to eliminate the drifts with knowledge of performance in previous trials. Young healthy subjects produced force at 20% of the maximal force level by one finger at a time. There was no significant difference among the fingers in the root mean square error of force during performance with visual feedback. Turning visual feedback off caused force drift to lower magnitudes. The magnitude of force drift was the largest during tasks performed by the Index finger. After each block of twelve trials, the subjects were given feedback on the drift magnitude in that block and used it to correct performance in future trials. There was a total of six blocks. The magnitude of drift correction between consecutive blocks correlated with the magnitude of drift in the earlier block only after the second and fourth blocks. The Index finger failed to improve its performance more than other fingers and demonstrated significant residual drifts to lower force magnitudes in the sixth block of trials. These findings falsified both our hypotheses. Taken together with earlier studies showing advantage of the Index finger across a variety of tasks that require quick and accurate changes in performance, our results suggest that effector specialization along the stability-agility continuum is not limited to the phenomenon of cortical arm/hand dominance but can also be seen across fingers of a hand controlled by the same hemisphere, possibly reflecting the differences in the finger role in prehensile tasks.

FV 8. The effect of repeated blocks of intermittant theta burst stimulation (iTBS) over the dorsolateral prefrontal cortex (dlPFC) on fronto-striatal connectivity. A 18F-DesmethoxyFallypride (DMFP) Positron Emission Tomography study (PET)

Background. Frontostriatal networks are neural pathways formed between frontal lobe regions and striatum that is involved in cognitive and behavioural processes. Transcranial Magnetic Stimulation (TMS) is able to modulate connectivity in the human brain and it is widely used for clinical purposes to treat depression patients. This exploratory PET and TMS multimodal study would contribute to better understand the role of striatal dopaminergic neurotransmission in the fronto-striatal area. Objective. The main objective of the study is to investigate the fronto-striatal connectivity by measuring the release of dopamine in the striatum in response to an excitatory intermittent theta burst stimulation (iTBS) of the left-dlPFC. A PET measurement was performed by using the 18F-DesmethoxyFallypride (DMFP) radioligand, that is a high affinity receptor-antagonist which competes with endogenous Dopamine neurotransmitters for D2/D3 receptor binding. Methods. The study was conducted on 23 healthy participants, who underwent iTBS sham (control) and verum stimulations on separate days. The PET scan lasted 120 mins, consisting of 4 iTBS stimulations delivered to the left-DLPFC at 30 mins interval. In verum stimulation, 90% of resting motor threshold (rMT) was used as the stimulation intensity. The excitatory iTBS protocol is delivered in a sequence of trains (burst of 10 pulses in 2 secs having inter train interval of 8 secs), with a total duration of 190 secs. PET dynamic data was analysed using reference region method in which cerebellum was used as the reference region (due to lack of D2-D3 receptors). Binding Potentials (BP) are the main outcome measure representing the ligand binding which is inversely proportional to the Dopamine (DA) levels.Mean Binding Potentials in the sub-regions of the striatum (Nucleus Caudate and Putamen) were compared between the sham and verum stimulation using analysis of variance (ANOVA). Results. iTBS stimulation of the left DLPFC increased the dopamine release (as reflected by BPs) in the striatum areas (putamen and nucleus caudate) in the verum stimulation, as compared to sham stimulation.Although the increase in dopamine release did not differ between the first block of stimulation, we observed significant increase after two, three and fourth blocks of stimulation. Conclusion. Our data suggest that the efficiency of iTBS protocol can effectively enhance fronto-striatal connectivity by applying a higher number of stimuli (i.e., 3rd & 4th TMS block but not 1st-& 2nd block). This minimal time stimulation protocol can be used as a therapy for treating Depression patients by presenting it in the repeated blocks of short intervals. This scheme could prevent the long stimulation protocols, and be less painful. Fig. 1. Figure represents the statistically significant main effect of TMS . The verum stimulation shows a reduction of 8.6% [18F]DMFP Binding Potential as compared to the sham stimulation. Fig. 2. Percentage reduction in [18F] desmethoxyfallypride-binding potentials extracted from the difference of sham and verum stimulation in healthy subjects. Dose-dependent iTBS aftereffects seem to be more pronounced at 3rd block and 4th block respectively as compared to 1st and 2nd block of TMS.

125 Increased plasma renin activity during wake in a repetitive sleep restriction protocol

Abstract Introduction Insufficient sleep is associated with an increased risk of hypertension. It is well established that long-term BP regulation is modulated by the renin-angiotensin-aldosterone system (RAAS) and chronic kidney disease is a strong independent risk factor for development of cardiovascular disease. This study investigated the biomarkers of RAAS and renal function during repetitive exposures to controlled, experimental sleep restriction (SR). We hypothesized an upregulation of RAAS and increased markers of impaired renal function. Methods Twenty-one healthy participants (11 women, average age 31±2 years) completed the 22-day in-hospital SR protocol: permitted 4h of sleep/night from 0300-0700 for 3 nights followed by a recovery sleep, repeated 4 times. Blood samples were collected and plasma renin activity (PRA) was assessed in the morning (7:05am) and in the evening before bedtime (22:45pm) at baseline, experimental days (3rd day of each of the 4 blocks), and recovery. Urinary albumin to creatinine ratio (ACR) was measured from 24-h urinary collection at baseline, first and fourth SR blocks. Estimated glomerulus filtration rate (eGFR) was calculated based on the serum cystatin C levels at baseline and last block of SR. Results Percent change of evening PRA significantly increased during 4 blocks of SR and recovery (SR effect p=0.039), but not morning PRA (SR effect p=0.34). Specifically, evening PRA increased up to 98.4% in the first (p<0.01), 61.3% in the second (p=0.04) SR blocks, and 57.5% (p=0.05) in recovery. Urinary ACR showed no significant changes during first or fourth SR blocks (SR effect p=0.28). In addition, eGFR did not change in the fourth SR block compared to BL (paired t-test, p=0.27). Conclusion We did not see increased markers of impaired renal function (ACR or eGFR). Rather, short-term repetitive exposures to SR significantly increased percent change of PRA measured before bedtime, and evening PRA did not return to BL level during recovery. Our results suggested that sleep deficiency may contribute to hypertension through upregulation of RAAS during wake time. Support (if any) SRSF (CDA to Huan Yang), NIH (R01HL106782 to Dr. Janet Mullington), Harvard Catalyst, Harvard Clinical and Translational Science Center (UL1TR001102).

Trauma exposure, PTSD, and suboptimal HIV medication adherence among marginalized individuals connected to public HIV care in Miami.

Individuals living with HIV report disproportionately high levels of trauma exposure and PTSD symptoms, both which have been associated with suboptimal ART adherence. Often conflated, the question arises as to which construct is driving subsequent HIV self-care behavior. Given the HIV disparities among Black and Hispanic/Latinx individuals, and that Miami is a geographic region with a high racial/ethnic minority make up and a unique socioeconomic environment, it is important to explore factors related to HIV outcomes in Miami to mitigate its uncontrolled epidemic. This study aimed to examine the association of trauma exposure, PTSD symptoms, and relevant additional key factors with adherence to ART among a sample of majority Black and Hispanic/Latinx individuals who are economically marginalized receiving public HIV care in Miami, FL (N = 1237) via a cross-sectional survey. Sequential linear regression was used to examine the study aim in four blocks: (1) trauma, (2) PTSD symptoms, and key covariates of ART adherence including (3) depression and substance use (potential psychological covariates), and (4) indicators of socioeconomic status (potential structural covariates). In the first block, trauma exposure was associated with worse adherence. However, in the second block, the association with trauma dropped and PTSD was significantly associated with worse adherence. Of note, for those experiencing high levels of trauma exposure, adherence was negatively impacted regardless of PTSD. When other key factors associated with adherence were entered in the third and fourth blocks, neither trauma exposure nor PTSD were uniquely significant. In this final model, depression, substance use, and unstable housing were uniquely associated with worse adherence. Trauma-informed models of HIV care that holistically address co-occurring factors are warranted to cater to communities with HIV health disparities and keep them from falling off the HIV care continuum.

Decision-Making Deficits Are Associated With Learning Impairments in Female College Students at High Risk for Anorexia Nervosa: Iowa Gambling Task and Prospect Valence Learning Model.

This study investigated deficits in decision-making ability in female college students at high risk for anorexia nervosa (AN) using the Iowa Gambling Task (IGT) and the prospect valence learning (PVL) model. Based on scores on the Korean version of the Eating Attitude Test-26 (KEAT-26), participants were assigned to either the high risk for AN group (n = 42) or the control group (n = 43). The high risk for AN group exhibited significantly lower total net scores and block net scores on the third, fourth, and fifth blocks of the IGT than the control group did. The high risk for AN group selected cards significantly more often from the disadvantageous A and B decks and less often from the advantageous D deck than the control group did. In addition, the block net scores of the high risk for AN group did not differ across the five blocks, whereas those of the control group increased as the trials progressed. There was a significant negative correlation between IGT total net score and total score on the KEAT−26. The high risk for AN group had significantly lower values than the control group on the learning and response consistency parameters of the PVL model. These results indicate that female college students at high risk for AN have deficits in decision-making ability, and that these deficits are related to difficulties in remembering experience obtained from earlier trials and applying it to later trials. These difficulties further lead them to make decisions randomly.

Effect of Water Stress on the Yield of Selected Vegetable Crops in the Southern Guinea Savannah Ecological Zone of Nigeria

Water stress effect on the yield of tomato (Lycopersicum Esculentum) and onion (AlliumCepa) crops was carried. This study is aimed at understanding the required amount of water needed by onion and tomato plants daily and to predetermine the yield expected from scheduled irrigation under limited water supply. Randomised complete block design experimental layout was employed and replicated five times. The irrigation interval observed was controlled on the first block of regular four days; the second, third and fourth blocks were irrigated six, seven, and nine days respectively. The result of onion showed the highest yield of 31.5 kg/plot (12 t/ha) from the four days regular irrigation interval, followed by six days irrigation interval with a yield of 30.9 kg/plot (11.77 t/ha). The lowest yield of 18.3 kg/plot (6.97 t/ha) was obtained for the nine days irrigation interval. Similarly, the highest yield of 43.1 kg/plot (16 t/ha) in regular four days irrigation interval and the lowest yield of 13.4 kg/plot (5.1 t/plot) for nine days interval was recorded for tomato. The result of this study shows that irrigating at an interval of four to five days has the highest significant yield of 16 t/ha and under critical conditions, the farmer can irrigate seven days as up to 65% - 70% yield was obtained. Irrigation should not be scheduled nine (9) days because about 42% of the yield is lost. It is therefore concluded that the yield water use relationship shows that both onion and tomato crops increases with an increase in the rate of seasonal evapotranspiration provided water application rate does not exceed the required amount at the required amount.

PO-267 Effects of long-term exercise on executive function for young people

Objective Executive function is a cognitive control process that monitors, adjusts and plans task activities. Relevant studies have shown that exercise have positive impacts on executive function of human body, but previous studies mostly focus on children or elderly, the study of young people is not in-depth. This study explores whether exercise affects the executive control function of young people
 by comparing who have the habit of exercising all the year round with who have been sedentary.
 Methods 12 graduate students from the Graduate School of Capital University of Physical Education and sports were taken as participants. According to the exercise habits, 6 participants with long-term exercise habits were divided into exercise group and 6 participants with sedentary and low-activity habits were divided into control group. The E-prime software was used to program classic arrows Flanker task to measure the execution control function of participants. The formal experimental procedure was divided into four blocks. The first and third blocks were consistent tasks, the second and fourth blocks were inconsistent tasks. The SPSS23.0 was used to analyze the experimental data.
 Results The behavior data were analyzed with 2 (exercise habit group)*2 (task type) repeated measurement ANOVA to investigate the responsiveness of different exercise habits to flanker task. The results showed that for accuracy, the main effect of task type was significant F (1,10) = 21.729, P =.001, 2 =.685, and the interaction effect between task type and group was significant F (1,10) = 7.519, P =.021, 2 =.429, indicating that the participants with long-term exercise habits had higher accuracy than those who with sedentary. The accuracy of consistent tasks is higher than inconsistent tasks. For response time, the main effect of task type was significant F (1,10) = 5.277, P =. 044, 2 =. 345; the interaction effect of task type and group was not significant F (1,10) =. 107, P =. 751, 2 =. 011, indicating that there were differences in response time between participants in the process of accomplishing consistent and inconsistent tasks, but there was no significant difference in the reaction time between participants with long-term exercise habits and sedentary.
 Conclusions Long-term exercise may has positive effects on executive function of young people, especially on accuracy of completing cognitive process, and the related brain mechanisms need to be further studied.

P105 Modulating inter-hemispheric coherence to influence behavior – A TMS-EEG study

Inter-hemispheric coherence (IHC) is one of the EEG parameters that measures synchronization of oscillations originating from brain regions of different hemispheres and thereby the functional connectivity between them. We know that IHC is critical for tasks such as midline object recognition that involves merging information obtained from the 2 hemispheres. In a previous study, it was observed that midline object recognition is associated with transient increase in IHC over temporo-parietal areas in the alpha frequency range (Mima et al., 2001). Whether this association is causal, remains unknown. In the current study we aimed at determining the causal association of inter-hemispheric alpha coherence to midline object recognition. Several studies have used TMS as an effective tool to entrain intrinsic brain oscillations. We interfered with the IHC by using unilateral or bilateral, synchronous or asynchronous repetitive transcranial magnetic stimulation (rTMS) pulses. Our hypothesis was that asynchronous rTMS would reduce IHC thereby impairing midline object recognition. We recruited 13 healthy subjects for the study. All subjects first participated in a screening session where the threshold intensity for blocking object recognition and the optimal coil orientation for TMS was determined. In the main experiment session, they were asked to perform the object recognition task in four blocks. During the first block, the individual alpha coherence frequency was determined by recording EEG during object recognition. During the second, third and fourth blocks rTMS was delivered in every trial with simultaneous EEG recording. Trains of 7 TMS pulses were administered over left and/or right lateral occipital gyrus at 80% of threshold intensity blocking object discrimination or 60% maximum stimulator output whichever was smaller. Our primary outcome measure for the object recognition task was d-prime or sensitivity index. Our results have not shown a significant effect of rTMS on object recognition. The EEG data is currently being analyzed to look for entrainment effects. We think that this absence of effect on behavior could be due to a ceiling effect in task performance, wrong stimulation site or sub-optimal stimulation paradigm. We are currently performing additional experiments to address the above issues.

Effect of systemic bevacizumab in severe hereditary hemorrhagic telangiectasia associated with bleeding

Effect of systemic bevacizumab in severe hereditary hemorrhagic telangiectasia associated with bleeding

Decision-making deficits in patients with chronic schizophrenia: Iowa Gambling Task and Prospect Valence Learning model.

PurposeDecision-making is the process of forming preferences for possible options, selecting and executing actions, and evaluating the outcome. This study used the Iowa Gambling Task (IGT) and the Prospect Valence Learning (PVL) model to investigate deficits in risk-reward related decision-making in patients with chronic schizophrenia, and to identify decision-making processes that contribute to poor IGT performance in these patients.Materials and methodsThirty-nine patients with schizophrenia and 31 healthy controls participated. Decision-making was measured by total net score, block net scores, and the total number of cards selected from each deck of the IGT. PVL parameters were estimated with the Markov chain Monte Carlo sampling scheme in OpenBugs and BRugs, its interface to R, and the estimated parameters were analyzed with the Mann–Whitney U-test.ResultsThe schizophrenia group received significantly lower total net scores compared to the control group. In terms of block net scores, an interaction effect of group × block was observed. The block net scores of the schizophrenia group did not differ across the five blocks, whereas those of the control group increased as the blocks progressed. The schizophrenia group obtained significantly lower block net scores in the fourth and fifth blocks of the IGT and selected cards from deck D (advantageous) less frequently than the control group. Additionally, the schizophrenia group had significantly lower values on the utility-shape, loss-aversion, recency, and consistency parameters of the PVL model.ConclusionThese results indicate that patients with schizophrenia experience deficits in decision-making, possibly due to failure in learning the expected value of each deck, and incorporating outcome experiences of previous trials into expectancies about options in the present trial.

Применение метода коэрцитивной силы сегодня

The article shows an attempt to group the main areas of practical applications for NDT of ferromagnetic metal mechanical properties by measuring a magnetic parameter – a coercive force. All the areas are divided into 5 blocks. The first block represents coercivity application for process inspection and acceptance inspection at metal production. The second and third blocks represent in-service local and integral inspection of equipment and its parts current status. The fourth and fifth blocks present coercimetric fatigue state estimation of austenitic (initially non-magnetic) stainless steels. Using a coercimetric inspection (the tried-and-true method for ferromagnetic steels) is getting possible due to austenite transformation followed by initiation of ferromagnetism. In this case the fatigue damage level can also be estimated. The cumulative coercimetric effect of austenite degradation is even more evident than that for classic ferromagnetic steels. Thus the task of fatigue testing for stainless austenitic steels can be considered solved at practice level.

Does electronic cigarette liquid nicotine concentration and user experience influence plasma nicotine concentration?

Does electronic cigarette liquid nicotine concentration and user experience influence plasma nicotine concentration?

Content analysis of cannabis smartphone applications

Content analysis of cannabis smartphone applications

A Subgroup Analysis of the Impact of Self-testing Frequency on Examination Scores in a Pathophysiology Course

To determine if the frequency of self-testing of course material prior to actual examination improves examination scores, regardless of the actual scores on the self-testing. Practice quizzes were randomly generated from a total of 1342 multiple-choice questions in pathophysiology and made available online for student self-testing. Intercorrelations, 2-way repeated measures ANOVA with post hoc tests, and 2-group comparisons following rank ordering, were conducted. During each of 4 testing blocks, more than 85% of students took advantage of the self-testing process for a total of 7042 attempts. A consistent significant correlation (p≤0.05) existed between the number of practice quiz attempts and the subsequent examination scores. No difference in the number of quiz attempts was demonstrated compared to the first testing block. Exam scores for the first and second testing blocks were both higher than those for third and fourth blocks. Although self-testing strategies increase retrieval and retention, they are uncommon in pharmacy education. The results suggested that the number of self-testing attempts alone improved subsequent examination scores, regardless of the score for self-tests.

Movement chunking during sequence learning is a dopamine-dependant process: a study conducted in Parkinson’s disease

Chunking of single movements into integrated sequences has been described during motor learning, and we have recently demonstrated that this process involves a dopamine-dependant mechanism in animal (Levesque et al. in Exp Brain Res 182:499-508, 2007; Tremblay et al. in Behav Brain Res 198:231-239, 2009). However, there is no such evidence in human. The aim of the present study was to assess this question in Parkinson's disease (PD), a neurological condition known for its dopamine depletion in the striatum. Eleven PD patients were tested under their usual levodopa medication (ON state), and following a 12-h levodopa withdrawal (OFF state). Patients were compared with 12 healthy participants on a motor learning sequencing task, requiring pressing fourteen buttons in the correct order, which was determined by visual stimuli presented on a computer screen. Learning was assessed from three blocks of 20 trials administered successively. Chunks of movements were intrinsically created by each participant during this learning period. Then, the sequence was shuffled according to the participant's own chunks, generating two new sequences, with either preserved or broken chunks. Those new motor sequences had to be performed separately in a fourth and fifth blocks of 20 trials. Results showed that execution time improved in every group during the learning period (from blocks 1 to 3). However, while motor chunking occurred in healthy controls and ON-PD patients, it did not in OFF-PD patients. In the shuffling conditions, a significant difference was seen between the preserved and the broken chunks conditions for both healthy participants and ON-PD patients, but not for OFF-PD patients. These results suggest that movement chunking during motor sequence learning is a dopamine-dependent process in human.

Intersectin 1 forms a complex with adaptor protein Ruk/CIN85 in vivo independently of epidermal growth factor stimulation

Intersectin 1 (ITSN1) is an adaptor protein involved in clathrin-mediated endocytosis, apoptosis, signal transduction and cytoskeleton organization. Here, we show that ITSN1 forms a complex with adaptor protein Ruk/CIN85, implicated in downregulation of receptor tyrosine kinases. The interaction is mediated by the SH3A domain of ITSN1 and the third or fourth proline-rich blocks of Ruk/CIN85, and does not depend on epidermal growth factor stimulation, suggesting a constitutive association of ITSN1 with Ruk/CIN85. Moreover, both proteins colocalize in MCF-7 cells with their common binding partner, the ubiquitin ligase c-Cbl. The possible biological role of the interaction between ITSN1 and Ruk/CIN85 is discussed.

Investigators' Workshop Sunday Evening Poster Session

Abstract Kwee Thio*, N. Rensing*, S. Maloney†, D. Wozniak†, C. Xiong‡ and K. Yamada**Neurology, Washington University, St. Louis, MO; †Psychiatry, Washington University, St. Louis, MO and ‡Biostatistics, Washington University, St. Louis, MO Rationale: Ketogenic diets (KD) have anticonvulsant effects, but their effects on cognition are less clear. Therefore, we examined the behavioral performance of rats fed a KD on tests of locomotor activity and Pavlovian fear conditioning. We also examined in vivo medial perforant path long-term potentiation (LTP) in rats fed a KD. Methods: Rats were fed a standard diet (SD), a KD, or a calorie-restricted diet (CR) beginning on postnatal day (PD) 21. Rats on the ketogenic diet received 92% of their calories from fat. Rats on the CR served as a control for the slower weight gain experienced by KD fed rats. CR fed rats were given the same chow as the SD but were calorie restricted to allow their weight to match that of the rats fed the KD. On PD 35–60, a 1-hour locomotor activity test and a conditioned fear (contextual or auditory cue) test were performed. On PD 42–45, in vivo median perforant path LTP was assessed by recording field excitatory postsynaptic potentials (fEPSPs) from the dentate gyrus before and after delivering a tetanus. Results: Rats fed the CR and KD showed slower weight gain, but only the KD fed rats had elevated serum β-hydroxybutyrate levels as we have reported previously. KD and SD fed rats did not differ in performance on several activity-related variables (total ambulations, rearing, time at rest). However, CR fed rats exhibited significant hyperactivity relative to the other two groups in terms of total ambulations (whole body movements), particularly during the last 4, 10-minute blocks of testing (p < 0.0008). The CR fed rats also reared significantly more often than either of the other two groups during the fourth and fifth time blocks (p < 0.0008), and spent significantly less time at rest than the KD fed group (but not SD fed) over the 60 minute test (p = 0.002). KD and SD fed groups also performed similarly during the conditioned fear measures of baseline testing, tone-shock training, or during contextual fear or auditory cue testing. Although no significant overall Treatment effects were found in amounts of freezing during the contextual fear test, only the CR fed rats did not show evidence of contextual cue conditioning relative to the pre-test baseline. An ANOVA of the auditory cue data that yielded a significant Treatment by Time interaction, [F (14,280) = 2.13, p = 0.032], and subsequent significant contrasts showed that, on average across time, the CR fed group froze significantly less often than the KD or SD fed groups (p = 0.030 and 0.040, respectively). In vivo LTP in KD fed rats did not differ from rats fed the SD. CR fed rats exhibited LTP, but the magnitude of LTP in CR fed rats was smaller. A two-way repeated measures ANOVA revealed a significant main effect of diet (p = 0.049). Pairwise comparisons revealed that the magnitude of LTP for the CR (p = 0.02) but not the KD (p = 0.30) fed rats was smaller than the SD fed rats. Conclusions: These findings suggest that a KD does not adversely affect the cognitive functions and type of LTP examined. In contrast, a CR may have an adverse effect on the same parameters. (Supported by NIH & JDRF)