Memory failures are frustrating and often the result of ineffective encoding. One approach to improving memory outcomes is through direct modulation of brain activity with electrical stimulation. ...Previous efforts, however, have reported inconsistent effects when using open-loop stimulation and often target the hippocampus and medial temporal lobes. Here we use a closed-loop system to monitor and decode neural activity from direct brain recordings in humans. We apply targeted stimulation to lateral temporal cortex and report that this stimulation rescues periods of poor memory encoding. This system also improves later recall, revealing that the lateral temporal cortex is a reliable target for memory enhancement. Taken together, our results suggest that such systems may provide a therapeutic approach for treating memory dysfunction.
Neuroimaging experiments implicate the posterior cingulate cortex (PCC) in episodic memory processing, making it a potential target for responsive neuromodulation strategies outside of the ...hippocampal network. However, causal evidence for the role that PCC plays in memory encoding is lacking. In human female and male participants (
= 17) undergoing seizure mapping, we investigated functional properties of the PCC using deep brain stimulation (DBS) and stereotactic electroencephalography. We used a verbal free recall paradigm in which the PCC was stimulated during presentation of half of the study lists, whereas no stimulation was applied during presentation of the remaining lists. We investigated whether stimulation affected memory and modulated hippocampal activity. Results revealed four main findings. First, stimulation during episodic memory encoding impaired subsequent free recall, predominantly for items presented early in the study lists. Second, PCC stimulation increased hippocampal gamma-band power. Third, stimulation-induced hippocampal gamma power predicted the magnitude of memory impairment. Fourth, functional connectivity between the hippocampus and PCC predicted the strength of the stimulation effect on memory. Our findings offer causal evidence implicating the PCC in episodic memory encoding. Importantly, the results indicate that stimulation targeted outside of the temporal lobe can modulate hippocampal activity and impact behavior. Furthermore, measures of connectivity between brain regions within a functional network can be informative in predicting behavioral effects of stimulation. Our findings have significant implications for developing therapies to treat memory disorders and cognitive impairment using DBS.
Cognitive impairment and memory loss are critical public health challenges. Deep brain stimulation (DBS) is a promising tool for developing strategies to ameliorate memory disorders by targeting brain regions involved in mnemonic processing. Using DBS, our study sheds light on the lesser-known role of the posterior cingulate cortex (PCC) in memory encoding. Stimulating the PCC during encoding impairs subsequent recall memory. The degree of impairment is predicted by stimulation-induced hippocampal gamma oscillations and functional connectivity between PCC and hippocampus. Our findings provide the first causal evidence implicating PCC in memory encoding and highlight the PCC as a favorable target for neuromodulation strategies using
connectivity measures to predict stimulation effects. This has significant implications for developing therapies for memory diseases.
Abstract
Objective
Epilepsy affects 3.4 million people in the United States and 70 million globally. A third have intractable epilepsy, epilepsy that is not well-controlled by medication. ...Understanding memory and cognitive functioning in this population will further comprehension of cognitive changes in this population. However, few neuropsychological measures can be administered on a regular basis without compromising reliability. This study investigated experimental and standardized memory measures in patients with intractable epilepsy.
Methods
Individuals with intractable epilepsy (n = 188; mean age = 37.5 years) scheduled to undergo depth electrode surgery were given a comprehensive neuropsychological battery including Rey-Auditory Verbal Learning Test (RAVLT) or California Verbal Learning Test (CVLT). During their stay in the hospital following surgery, participants were also given an experimental computerized verbal list learning test multiple times throughout their stay.
Results
The experimental task and standardized task were significantly associated on total recall (r = 0.348, p < 0.01) and immediate learning (r = 0.383, p < 0.01).
Conclusions
Understanding memory in individuals with epilepsy will help further clinical treatment and outcomes for these individuals. A task such as our experimental verbal list learning task that can be administered frequently and consistently could make serial testing possible. This would be particularly helpful in situations where rapid change occurs, or regular monitoring of symptoms is needed. Clinically, this type of testing could lead to better understanding of cognitive symptoms over time.
Abstract
Objective
Neuropsychological assessment of ethnoracially diverse patients can be challenging for various reasons, including limited normative data, differing worldviews, stigma, and mental ...health service utilization and access. This case study describes the use of a comprehensive neuropsychological assessment to assist with differential diagnosis and treatment recommendations.
Method
The patient was a 25-year-old Asian and White female who was referred to rule out attention deficit hyperactivity disorder (ADHD). Her history included homeschooling through 8th grade, uncommon sleep disturbances, seasonal allergies, and a diagnosis of major depressive disorder. Regarding sleep disturbance, she endorsed monthly episodes of sleeping for up to 12 hours at a time, sometimes sleeping and waking on the floor or elsewhere not in her bedroom. She underwent a comprehensive neuropsychological evaluation.
Results
The patient’s cognitive profile was generally intact, with relative cognitive inefficiencies in visuospatial/visuoconstructional abilities, working memory, and processing speed domains. She also endorsed clinically significant levels of anxiety. These findings, in conjunction with family history and sleep disturbance, raised concern for Klein-Levin Syndrome (KLS) and the impact of co-occurring anxiety. A sleep study, educational/vocational accommodations, psychotherapy, and follow up evaluation in one year were recommended.
Conclusion
While sleep–wake disorders and ADHD can co-occur, sleep–wake disorders can be overlooked by mental health professionals, thus increasing the likelihood of misdiagnosis and potential for harm. Adding additional complexity, expressions of psychological distress vary cross-culturally. Taken together, neuropsychological training must include frameworks that attend to cultural and contextual factors. These cases may frequently be seen in the context of educational or vocational concern referrals.
Abstract
Objective
Access to neuropsychological services for bilingual individuals remains limited and more research is needed to clarify benefits of testing in both languages. Additionally, certain ...disorders remain underdiagnosed in the Hispanic/Latinx population. This case study describes the use of a comprehensive culturally and linguistically appropriate neuropsychological evaluation to leverage linguistic, cognitive, and social context to assist with establishing needed care and diagnostic clarity.
Method
The patient was a 40-year-old right-handed Spanish-bilingual Hispanic male community-referred to rule out attention deficit hyperactivity disorder (ADHD). He learned English at the age of 4. History was remarkable for parasomnias in childhood, sleep disturbance, multiple closed head injuries, cannabis use, and chronic pain. He completed a comprehensive neuropsychological battery with measures in both Spanish and English.
Results
Cognitive findings revealed deficits in verbal memory, variable executive functioning, and better performances in English relative to Spanish. Findings from the evaluation supported a diagnosis of mild neurocognitive disorder secondary to untreated sleep–wake disturbance. Recommendations included reasonable occupational accommodations, sleep study, pain management, brief psychotherapy to address sleep hygiene, and re-evaluation in one year. Following the evaluation, the patient received 6-sessions of a highly structured treatment for insomnia and is no longer endorsing clinically significant levels of sleep disturbance.
Conclusion
Sleep–wake disorders are underdiagnosed among Hispanic/Latinxs, and these disorders can manifest with similar symptoms to ADHD. Without culturally and linguistically appropriate services, the likelihood of misdiagnosis and issues of access to treatment will persist. Importantly, the present evaluation was able to identify cognitive and linguistic strengths and weaknesses to best direct referral needs.
Abstract
Objective
The Cognitive Reserve (CR) Theory proposes protective factors that aid in acting against cognitive decline due to factors such as dementia and head injury. Here we conduct a ...narrative review of diverse perspectives in CR. We provide an overview of CR models not previously highlighted, as well as how traditional models of CR may not be applicable for all populations.
Data Selection
A review of the literature on diverse perspectives of CR was carried out through PubMED, Sage Research Methods (SRM) Core, and Web of Science: All Databases. Two specific types of articles were selected. We first looked at traditional models of CR (premorbid intelligence estimates and educational or occupational attainment) tested with diverse populations not historically represented in the original models. The second category of articles included an open-ended search of CR expressions outside of these traditional understandings (i.e., resiliency).
Data Synthesis
Reviewed evidence suggests that historical models of CR are not homogeneously valid across racial and ethnic groups. Other conceptualizations expand the understanding of CR and show evidence supporting CR expressions in bilingualism, personal social networks, and protective health behaviors, among others.
Conclusion
To the best of our knowledge, this is the first attempt to provide a comprehensive review of diverse perspectives in CR. The growing body of research suggests good support for alternative understandings of CR, and indicates reconsideration of historical understandings of CR within minoritized groups. Overall, the theory of CR should continue to evolve and incorporate factors relevant to diverse populations as the world population continues to rapidly diversify.
Abstract
Objective
Neuropsychological assessment of American Indian/Alaska Native (AI/AN) patients presents challenges due to limited normative data, stigma, possible differential validity of ...measures, and limited access to healthcare. Additionally, differentiating traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD) is increasingly important for proper diagnosis and treatment of indigenous patients. This case study describes the use of comprehensive neuropsychological testing across two timepoints to assist with treatment planning.
Methods
The patient was a 38-year-old Native American male referred by primary care to assist in educational, career, and treatment planning. His history was remarkable for TBI status post craniotomy and craniectomy. The patient completed initial and follow-up comprehensive neuropsychological evaluations. Follow-up was completed at 9-months following cranioplasty.
Results
On initial evaluation, the patient demonstrated deficits in immediate learning, delayed recall, executive functioning, processing speed, and fine motor abilities consistent with major neurocognitive impairment due to TBI. On follow-up evaluation, the patient demonstrated variable processing speed and executive functioning. Follow-up testing showed improvements in encoding of verbal information and immediate learning of visual information. Modest improvements were noted in processing speed, executive functioning, and fine motor skills. Follow-up testing evidenced declines in immediate learning, spontaneous recall, verbal fluency, and worsening PTSD symptoms.
Conclusion
While TBI and PTSD can co-occur, understanding how to differentiate cognitive profiles of each, while considering linguistic, sociocultural, and educational differences, is vital for proper diagnosis and treatment. Adherence to treatments following TBI can promote physical and cognitive improvements, though certain symptoms may worsen due to psychological symptoms, which may present differently across cultures.
While difficult to prevent introductions, scientific research can help guide control efforts of exotic, invasive species. South American island apple snails Pomacea insularum have quickly spread ...across the United States Gulf Coast and few control measures exist to delay their spread. Usually occupying cryptic benthic habitats, female apple snails crawl out of the water to de-posit large, bright pink egg clutches on emergent objects. To help identify the most likely place to find and remove clutches, we conducted four lab experiments to investigate what specific object qualifies （i.e. material; shape and height; plant species; natural and artificial） attracted P. insularum females to lay clutches. In our fourth experiment, we specifically examined the relationship between female size and reproductive output. To further understand reproductive output, we quantified experimental clutch chara-cteristics （height above water, dimensions, mass, approximate volume, number of eggs, hatching efficiency）. Pomacea insu-larum females laid more clutches on plant material, chose round over flat surfaces and failed to differentiate between tall and short structures. In comparison to a common native plant in the eastern US, Pontederia cordata, snails clearly preferred to lay clutches on a widely distributed exotic, invasive plant （wild taro, Colocasia esculenta）. Unexpectedly, smaller snails showed higher overall total fecundity as well as more eggs per clutch than larger snails. Therefore, hand removal efforts of large fe-males may not be enough to slow down clutch production. Collectively, our results indicate that conservationists and managers should search emergent plants for P. insularum clutches carefully to guard against established populations Current Zoology 57 （5）： 630-641, 2011.
The goal of this study was to assess the differences in high school juniors‘ overall essay writing scores when given a method of instruction (coping model, mastery model, and neither). After reading ...two articles that discussed opposing views on the same topic, participants in each group wrote an essay in response to a prompt stemming from the articles. Participants did the same for two subsequent essays as well as a post-test. Participants in the coping model group received explicit instruction on brainstorming, outlining, and essay writing as the teacher demonstrated think-alouds and wrote her thoughts on an overhead projector. Participants in the mastery model group received mastery examples of brainstorms, outlines, and essays. Participants in the control group received neither the coping nor the mastery model. However, their questions were answered without any examples being given. The post-test scores were analyzed using a one-way ANCOVA, which resulted in no statistical significance.
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