Updated July 9th, 2024
Research Spotlight
In Alzheimer's disease, the abnormal accumulation of proteins in the brain (amyloid-beta and hyperphosphorylated tau) leads to changes in the electrophysiological behaviour of neurons. The precise mechanisms that mediate their bidirectional interaction between protein accumulation and neuronal electrophysiology are not fully understood. Cabrera-Álvarez and colleagues propose a multiscale mathematical model of Alzheimer’s disease progression that links proteinopathy to neural activity changes. The model suggests that the alterations in inhibition, primarily driven by Aβ effects, are crucial in the observed electrophysiological shifts.
Have you ever wondered how experts' brains differ from non-experts' brains? In a research collaboration between Aston University and Nottingham University, researchers investigated this by recording the brain activity of police officers as they participated in virtual reality “shoot/don’t shoot” scenarios that were co-designed with police instructors (from Cleveland Police and Durham Constabulary). They found that specially trained police firearms officers made quicker decisions than age- and gender-matched novices. Experts also had distinct patterns of neural activity associated with their anterior cingulate cortex when initiating and making decisions. Coupled with the known roles of anterior cingulate cortex in behavior, this suggests that differences in performance between experts and novices when preparing against threat may be due to differences in orientation towards threat. Additionally, the observed brain activity differences suggest that experts may be “ready for action” again sooner than novices. This study is important for a variety of reasons. Understanding the intricacies of police decision making–especially concerning the use of firearms–may be vital to improving policy. Additionally, the use of virtual reality in this study was novel and could help improve the applicability of other kinds of behavioral research to reality. Finally, this study may inform future work aimed at investigating how decisions are made by those with expertise in different contexts.
Most-Discussed Research Published in June
Below are five Early Release articles that generated the most online discussion in June 2024, as measured by Altmetric. Altmetric data is available for all articles published in eNeuro on the Info & Metrics tab. Learn more about how the Altmetric score is calculated.
Healthy adult brains generate alpha oscillations, and individual subjects have different alpha oscillation frequencies, which impact how they dynamically process and attend to sensory information. Yet, little is known about the fine-scale temporal dynamics between sensory events and alpha phase and corresponding neuromodulation of auditory input processing. Here we use a novel closed-loop technology and individualized approach to play sounds at specific frontal alpha phases. We demonstrate novel alpha phase-dependent effects on auditory evoked responses, alpha levels, alpha phase coherence, and frequency. This individually tailored closed-loop approach has potential applications for research and health applications for a variety of neurological, developmental, and clinical disorders.
Previous studies have proposed that only the low-frequency oscillations of shared synaptic inputs to motor neurons, encompassing task-related and task-unrelated oscillations, are responsible for the generated muscle force. In our study, we investigated whether the acquisition of a new motor task involving precise force generation requires specific alterations in these shared synaptic inputs. Our findings demonstrated that, for both a hand muscle and a leg muscle, the skill acquisition was mediated by a reduction in shared synaptic oscillations unrelated to the required force fluctuations (i.e., physiological tremor band oscillations). Therefore, during the force-matching task learning, the central nervous system acts like a neural filter, modulating the synaptic weights of shared inputs to attenuate neural components unrelated to the specific task.
Although it is well-known that dopamine plays a principal role in reward learning, the temporal dynamics and the associated theoretical framework of the dopamine response to changing reward values are debated. Most studies conceptualize and classify dopamine signals as governed exclusively by either model-based or model-free processes. However, our work shows involvement of both processes: the temporal dynamics of dopamine response to conditioned stimuli appear model-based, and the persistence of reward-evoked dopamine to the reward itself appears model-free. The implication of our findings is that either model-free and model-based dynamics can operate in a mixed framework, or that these reinforcement-learning concepts are not apt in describing the activity of the mesolimbic dopamine system in this experimental context.
Short-Term Memory Capacity Predicts Willingness to Expend Cognitive Effort for Reward
We must often make decisions about when cognitive effort is worth the potential reward. Reward value, depression, and chronic stress in rodents can impact cognitive effort deployment decisions for reward, but factors like short-term memory ability can only be easily characterized in humans. We examined whether short-term memory ability, depression, chronic stress, and reward anticipation predict cognitive effort decisions for reward. In a short-term visual memory task with a choice of easier or harder trials for low versus high reward, we found that only short-term memory ability predicted more choices of high versus low effort trials. This research suggests that cognitive effort decisions could be driven by cognitive effort ability more than motivational factors like depression or chronic stress.
Animal models are essential to understand and develop therapies for diseases such as Alzheimer's disease (AD). Given the importance of the human retrosplenial cortex (RSC) in object-location associative learning and the success of these paradigms in human studies and in the clinic, it is of considerable value to establish a translational model of object-location learning for the rodent. We determined that lesions of the RSC in male rats following object-location paired-associates learning (PAL) led to impairments in object-location associative memory and new learning without affecting performance on tasks of the individual modalities (i.e., spatial and visual). These findings further validate the touchscreen PAL test as a viable translational test for modeling diseases, such as AD, in which RSC is compromised.
Stay updated on the latest research: Sign up and manage your Alerts to receive email alerts of table of contents, searching, and article citation alerts for both issues and Early Release.