Frontal Cortex Research Articles

Neural responses to camouflage targets with different exposure signs based on EEG

This study investigates the relationship between various target exposure signs and brain activation patterns by analyzing the EEG signals of 35 subjects observing four types of targets: well-camouflaged, with large color differences, with shadows, and of large size. Through ERP analysis and source localization, we have established that different exposure signs elicit distinct brain activation patterns. The ERP analysis revealed a strong correlation between the latency of the P300 component and the visibility of the exposure signs. Furthermore, our source localization findings indicate that exposure signs alter the current density distribution within the cortex, with shadows causing significantly higher activation in the frontal lobe compared to other conditions. The study also uncovered a pronounced right-brain laterality in subjects during target identification. By employing an LSTM neural network, we successfully differentiated EEG signals triggered by various exposure signs, achieving a classification accuracy of up to 96.4%. These results not only suggest that analyzing the P300 latency and cortical current distribution can differentiate the degree of visibility of target exposure signs, but also demonstrate the potential of using EEG characteristics to identify key exposure signs in camouflaged targets. This provides crucial insights for developing auxiliary camouflage strategies.

Comparing face viewpoint, expression and identity selectivity in fMRI-defined face patches of macaque frontal cortex

Comparing face viewpoint, expression and identity selectivity in fMRI-defined face patches of macaque frontal cortex

'Knock down the brain': a nonlinear analysis of electroencephalography to study the effects of sub-concussion in boxers.

Boxing is associated with a high risk of head injuries and increases the likelihood of chronic traumatic encephalopathy. This study explores the effects of sub-concussive impacts on boxers by applying both linear and nonlinear analysis methods to electroencephalogram (EEG) data. Twenty-one boxers were selected (mean ± SD, age 28.38 ± 5.5 years; weight 67.55 ± 8.90 kg; years of activity 6.76 ± 5.45; education 14.19 ± 3.08 years) and divided into 'beginner' and 'advanced' groups. The Montreal Cognitive Assessment and the Frontal Assessment Battery were administered; EEG data were collected in both eyes-open (EO) and eyes-closed (EC) conditions during resting states. Analyses of EEG data included normalized power spectral density (nPSD), power law exponent (PLE), detrended fluctuation analysis and multiscale entropy. Statistical analyses were used to compare the groups. Significant differences in nPSD and PLE were observed between the beginner and advanced boxers, with advanced boxers showing decreased mean nPSD and PLE (nPSD 4-7 Hz, p = 0.013; 8-13 Hz, p = 0.003; PLE frontal lobe F3 EC, p = 0.010). Multiscale entropy analysis indicated increased entropy at lower frequencies and decreased entropy at higher frequencies in advanced boxers (F3 EC, p = 0.024; occipital lobe O1 EO, p = 0.029; occipital lobe O2 EO, p = 0.036). These changes are similar to those seen in Alzheimer's disease. Nonlinear analysis of EEG data shows potential as a neurophysiological biomarker for detecting the asymptomatic phase of chronic traumatic encephalopathy in boxers. This methodology could help monitor athletes' health and reduce the risk of future neurological injuries in sports.

Changed resting-state connectivity of anterior insular cortex affects subjective pain reduction after knee arthroplasty: A longitudinal study

The mechanism of chronic knee osteoarthritis (OA) pain and postoperative pain due to knee arthroplasty has not been elucidated. This could be involved neuroplasticity in brain connectivity. To clarify the mechanism of chronic knee OA pain and postoperative pain, we examined the relationship between resting-state functional connectivity (rs-FC) and clinical measurements in knee OA before and after knee arthroplasty, focusing on rs-FCs with the anterior insular cortex (aIC) as the key region. Fifteen patients with knee OA underwent resting-state functional magnetic resonance imaging and clinical measurements shortly before and 6 months after knee arthroplasty, and 15 age- and sex-matched control patients underwent an identical protocol. Seed-to-voxel analysis was performed to compare the clinical measurements and changed rs-FCs, using the aIC as a seed region, between the preoperative and postoperative patients, as well as between the operative and control patients. In preoperative patients, rs-FCs of the aIC to the OFC, frontal pole, subcallosal area, and medial frontal cortex increased compared with those of the control patients. The strength of rs-FC between the left aIC and right OFC decreased before and after knee arthroplasty. The decrease in rs-FC between the left aIC and right OFC was associated with decreased subjective pain score. Our study showed a correlation between longitudinally changed rs-FC and clinical measurement before and after knee arthroplasty. Rs-FC between the aIC and OFC have the potential to elucidate the mechanisms of knee OA pain and postoperative pain due to knee arthroplasty.

Small striatal huntingtin inclusions in patients with motor neuron disease with reduced penetrance and intermediate HTT gene expansions.

Short tandem repeat expansions in the human genome are overrepresented in a variety of neurological disorders. It was recently shown that huntingtin (HTT) repeat expansions with full penetrance, i.e. 40 or more CAG repeats, which normally cause Huntington's disease (HD), are overrepresented in patients with amyotrophic lateral sclerosis (ALS). Whether patients carrying HTT repeat expansions with reduced penetrance, (36-39 CAG repeats), or alleles with intermediate penetrance, (27-35 CAG repeats), have an increased risk of ALS has not yet been investigated. Here, we examined the role of HTT repeat expansions in a motor neuron disease (MND) cohort, searched for expanded HTT alleles, and investigated correlations with phenotype and neuropathology. MND patients harboring C9ORF72 hexanucleotide repeat expansions (HREs) were included, to investigate whether HTT repeat expansions were more common in this group. We found a high prevalence of intermediate (range 5.63%-6.61%) and reduced penetrance (range 0.57%-0.66%) HTT gene expansions in this cohort compared to other populations of European ancestry, but no differences between the MND cohort and the control cohort were observed, regardless of C9ORF72HRE status. Upon autopsy of three patients with intermediate or reduced penetrance HTT alleles, huntingtin inclusions were observed in the caudate nucleus and frontal lobe, but no significant somatic mosaicism was detected in different parts of the nervous system. Thus, we demonstrate, for the first time, huntingtin inclusions in individuals with MND and intermediate and reduced penetrance HTT repeat expansions but more clinicopathological investigations are needed to further understand the impact of HTT gene expansion-related pleiotropy.

No evidence of altered language laterality in people who stutter across different brain imaging studies of speech and language.

A long-standing neurobiological explanation of stuttering is the incomplete cerebral dominance theory, which refers to competition between two hemispheres for 'dominance' over handedness and speech, causing altered language lateralization. Renewed interest in these ideas came from brain imaging findings in people who stutter of increased activity in the right hemisphere during speech production or of shifts in activity from right to left when fluency increased. Here, we revisited this theory using functional MRI data from children and adults who stutter, and typically fluent speakers (119 participants in total) during four different speech and language tasks: overt sentence reading, overt picture description, covert sentence reading and covert auditory naming. Laterality indices were calculated for the frontal and temporal lobes using the laterality index toolbox running in Statistical Parametric Mapping. We also repeated the analyses with more specific language regions, namely the pars opercularis (Brodmann area 44) and pars triangularis (Brodmann area 45). Laterality indices in people who stutter and typically fluent speakers did not differ, and Bayesian analyses provided moderate to anecdotal levels of support for the null hypothesis (i.e. no differences in laterality in people who stutter compared with typically fluent speakers). The proportions of the people who stutter and typically fluent speakers who were left lateralized or had atypical rightward or bilateral lateralization did not differ. We found no support for the theory that language laterality is reduced or differs in people who stutter compared with typically fluent speakers.

A - 143 Organic Psychiatric Disorders Due to Frontal Lobe Neoplasms

Abstract Objective This current study seeks to explore the presentation of psychiatric disorders as a preliminary symptom in individuals who suffer from frontal lobe neoplasms. Data Selection The primary sources of information for this literature review were Google Scholar, PubMed, ScienceDirect, and the National Institute of Health (NIH). Search terms included frontal lobe tumors/neoplasms, primary brain tumors, psychiatric/psychological, acquired disorders, and pseudo-depression/mania. This search was limited to articles published in English from January 2014 to December 2023. Inclusion criteria were studies that focused on frontal lobe tumors and psychiatric manifestations as a result of illness. Exclusion criteria were studies older than nine years or studies that explored traits of psychiatric illness (i.e., aggression) as opposed to a psychiatric diagnosis. Data Synthesis Frontal lobe neoplasms, accounting for a significant percentage of PTBs, have been found to impact the psychological well-being of patients, leading to a range of psychiatric manifestations that may appear before physiological symptoms. These include mood disorders (i.e., depression, manic episodes), psychotic episodes, and personality disorders. Due to the complexities of the frontal lobe, these manifestations are not linearly linked to frontal lobe lesions. Conclusion This study’s findings advocate for a multidisciplinary approach to treatment, emphasizing the need for neuropsychological evaluations pre- and post-tumor resection. It calls for heightened awareness among clinicians to consider organic causes behind psychiatric presentations, especially in atypical cases or when traditional treatments fail. Ultimately, this research contributes to a deeper understanding of the neuropsychiatric consequences of frontal lobe neoplasms and paves the way for more targeted and effective interventions.

The Relevance of Dual Language Experience in Interhemispheric Brain Connectivity in Older Adults

Abstract Objectives to analyze the volumes of sections of the corpus callosum (CC) and the integrity of the interhemispheric fibers that connect homotopic regions of the frontal and temporal lobes in bilinguals and monolinguals and to correlate neuroimaging data with cognitive measures and bilingual variables. Method 107 bilinguals and 89 monolinguals from the 1Florida ADRC were clinically diagnosed as cognitively normal (CN), MCI, or dementia; mean age = 71.28 (10.94). CC volume was calculated from a T1-weighted scan using Freesurfer. Free water (FW) and free water-corrected fractional anisotropy (FAt) maps were calculated from a diffusion MRI scan within frontal and temporal transcallosal tracts (TCATT). Results Bilinguals had a larger proportion of the anterior CC volume compared to monolinguals independent of the diagnostic group. FAt values in the Supplementary Motor Area (SMA) and the inferior temporal lobe tracts (IT TCATTs) were higher in bilinguals compared to monolinguals indicating better white matter integrity. A significant interaction demonstrated that these values were higher in bilinguals for the dementia group. Correlations were significant between the SMA FW values and several cognitive tests particularly executive function tests in both language groups. In bilinguals, the IT TCATTs correlated with language test scores. FAt in the SMA TCATT correlated with the percentage of English exposure and FAt in the IT TCATTs positively correlated with English proficiency. Conclusions Bilingualism interacts with cognitive status in aging and is associated with CC volume and the integrity of white matter in the frontal and temporal lobes supporting its role in the increase of neural reserve.

Morphometric Characteristics of Postmortem Changes in the Brain of Newborns Depending on the Duration of the Postmortem Period.

The morphometric characteristics of brain tissue were studied based on autopsy material from 49 deceased newborns divided into 7 groups based on the time after death. Samples were taken from the upper (frontal lobe) and lower (occipital lobe) regions relative to the supine position of the body. Paraffin sections were prepared from these samples and stained with hematoxylin and eosin. Histological preparations were analyzed using an image analysis system to determine the area of gliocyte nuclei, cross-cut blood vessels, and expanded area around them in the white matter of the brain. Based on these data, severity indices were calculated for both cellular (pericellular) and vascular (perivascular) expansion. The dynamics of changes in morphometric parameters within the range of cellular and vascular alterations on brain tissue specimens, which reflect the development of postmortem hypostasis and autolysis in this organ, can be used to estimate the duration of the postmortem interval. At the same time, these changes, when combined with other non-specific postmortem findings, should be distinguished from long-term pathological processes and diseases that may have occurred during life.

Absence of TNFR1 promotes a protective response in the early phase of hepatic encephalopathy induced by thioacetamide in mice

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome with a wide spectrum of cognitive deficits, motor impairment, and psychiatric disturbances resulting from liver damage. The cytokine TNF has been considered the main cytokine in the development and progression of HE, with a pivotal role in the initiation and amplification of the inflammatory cascade. The aim of the present study was to evaluate the involvement of TNF type 1 receptor (TNFR1) in locomotor deficits and in the levels of TNF, IFN-γ, IL-6, IL-10, IL-12p70, CCL2, CX3CL1 and BDNF from the frontal cortex and hippocampus of TNFR1 knockout mice (TNFR1-/-) mice with HE induced by thioacetamide. Wild-type (WT) animals with HE developed locomotor deficit. The absence of TNFR1 absence of TNFR1 in HE animals attenuated the locomotor activity impairment in parallel with a balanced neuroinflammatory environment 24 h after the administration of thioacetamide. Taken together, the data suggests that the absence of TNFR1 promoted a protective response in the early phase of hepatic encephalopathy induced by thioacetamide in mice.

Not All Stroop-Type Tasks Are Alike: Assessing the Impact of Stimulus Material, Task Design, and Cognitive Demand via Meta-analyses Across Neuroimaging Studies.

The Stroop effect is one of the most often studied examples of cognitive conflict processing. Over time, many variants of the classic Stroop task were used, including versions with different stimulus material, control conditions, presentation design, and combinations with additional cognitive demands. The neural and behavioral impact of this experimental variety, however, has never been systematically assessed. We used activation likelihood meta-analysis to summarize neuroimaging findings with Stroop-type tasks and to investigate whether involvement of the multiple-demand network (anterior insula, lateral frontal cortex, intraparietal sulcus, superior/inferior parietal lobules, midcingulate cortex, and pre-supplementary motor area) can be attributed to resolving some higher-order conflict that all of the tasks have in common, or if aspects that vary between task versions lead to specialization within this network. Across 133 neuroimaging experiments, incongruence processing in the color-word Stroop variant consistently recruited regions of the multiple-demand network, with modulation of spatial convergence by task variants. In addition, the neural patterns related to solving Stroop-like interference differed between versions of the task that use different stimulus material, with the only overlap between color-word, emotional picture-word, and other types of stimulus material in the posterior medial frontal cortex and right anterior insula. Follow-up analyses on behavior reported in these studies (in total 164 effect sizes) revealed only little impact of task variations on the mean effect size of reaction time. These results suggest qualitative processing differences among the family of Stroop variants, despite similar task difficulty levels, and should carefully be considered when planning or interpreting Stroop-type neuroimaging experiments.

A - 103 Exploring the Diagnostic Criteria for Alcohol-Related Dementia: a Case Study

Abstract Objective Excessive and chronic alcohol use can cause structural/functional abnormalities in the brain, including cognitive impairment (CI) (Harper, 2009). Despite these established risks, alcohol-related dementia (ARD) has received little recognition, mainly due to lack of a distinct pathophysiological profile. Through a case differential approach (concussion vs. ARD), the authors aim to clarify diagnostic criteria for ARD. Methods A 56-year-old right-handed male presented to the emergency room after fall with head strike (no loss of consciousness) with alcohol withdrawal delirium. Symptoms of cerebellar ataxia and CI of 6-month duration were noted. Past medical history was significant for alcohol use (four standard units per day), hyperlipidemia, tobacco use, and depression/anxiety. Neuroimaging revealed cerebral atrophy and chronic small vessel ischemic disease. A neuropsychological evaluation (NPE) was conducted 18 days post-fall. Results NPE revealed relative weaknesses in working memory, complex attention, and visual abstraction. Impairments were noted in visuospatial organization/planning, processing speed, basic attention, verbal fluency, and verbal memory. Motor examination was evident for intention tremor. Conclusion Brain changes associated with ARD include volume loss, altered glucose metabolism, reduced neuronal density, changes in frontal lobe function, and white matter loss. In contrast, individuals affected by concussions may encounter challenges with attention/concentration, processing speed, and working memory. Distinguishing a clear diagnostic profile for ARD is difficult due to high rates of concomitant concussion in this population. The patient’s deficits exceed those expected due to concussion alone, with an anticipated cognitive recovery timeframe of 7–14 days (Iverson, 2006). Furthermore, neuroimaging and NPE results support the diagnostic hypothesis of ARD.

B - 21 11-Year Longitudinal Study of a Competitive Swimmer Following a Severe TBI

Abstract Objective Symptoms of severe traumatic brain injuries (TBIs) are oftentimes significant, long lasting, and treated by a variety of medications and therapies. Although exercise is known to be beneficial for brain health, the effects of substantial exercise on recovery following severe TBI (sTBI) in female athletes are undiscovered. Method This case study examines a 51-year-old woman who sustained a sTBI, involving multiple hemorrhagic contusions to the right cerebellum, inferior bilateral frontal lobes, anterior left temporal lobe, and diffuse axonal injury on 8/5/13 from a bicycle accident, resulting in a 13-day coma and cognitive impairment. She underwent 6 brain surgeries, an artificial skull implant and intensive therapies. Before the accident, she was a competitive swimmer and triathlon racer. Despite being told that she would never swim again, she resumed swimming on 09/1/14. She swims 6 days a week for 90-minutes a day, winning open water races. Results Examination from four neuropsychological assessments over 11 years provide substantial longitudinal data. Results revealed improvement over the 4 testing periods particularly on processing speed, verbal fluency, and Boston Naming Test with t-score differences ranging between 8 and 24. Additionally, she performed in the average range on General Abilities Index, NAB Mazes, and Trail Making Test across all four assessments. Conclusion This longitudinal case study provides evidence that extensive swimming is associated with cognitive recovery from sTBI in a female athlete and documents her return to high level exercise and competition. Evidence suggests that carefully tailored and monitored exercise programs can benefit long term cognitive following from sTBI.

A - 85 Age-Related Differences in Cognitive Mechanisms: Exploring the Role of Processing Speed in Working Memory and Prospective Memory

Abstract Objective Research links working memory (WM) and prospective memory (PM) on cognitively demanding tasks. Older adults demonstrate more frontal lobe activation than young adults during WM and PM tasks; however, the underlying mechanisms remain unclear. The current study hypothesized processing speed (PS) as a mediator between WM and PM with age cohort as a possible moderator. Method Healthy older adults (n = 80; age 60–89, M = 72.51, SD = 7.08) and young adults (n = 63; age 18–29, M = 19.27, SD = 2.12) were administered WAIS-IV Digit Span, WAIS-IV Coding, and the Virtual Kitchen Protocol for Prospective Memory. Results A moderated mediation model revealed that WM positively influenced PM (c:B = 0.69, p < 0.001) with a positive indirect relationship through PS among older adults (ab:B = 0.26, 95% CI [0.13, 0.43]), but not young adults (ab:B = −0.08, 95% CI [−0.19, 0.03]). Conclusion PS appears to play a significant role in older adults’ use of WM for PM but not in young adults. This could suggest that older adults recruit additional cognitive resources – those involved in PS – as a compensatory strategy for real-world PM tasks, which would support prior research indicating that diminished functioning in older adults results from reduced ability to redirect neurocognitive networks. Alternatively, age-related declines in PS could be a root cause underlying both worse WM and worse PM in older adults, as postulated by Salthouse. Future research would benefit from further differentiating the direction of influences between WM, PS, and PM in older adults.

A - 27 Case Study Approach to Initial Exploration of Adaptations of Cognitive Behavioral Therapy (CBT) for Non-Epileptic Seizures (NES) in the Context of Cognitive Impairment

Abstract Objective The following case study seeks to review implementation of CBT for NES, discuss psychotherapeutic adaptations and outcomes while balancing treatment fidelity, and offer preliminary recommendations for expansion of psychotherapeutic modalities for individuals with cognitive impairment. Methods 49-year-old Hispanic male with a history of mixed epileptic (non-lesional frontal lobe medically refractory) and non-epileptic events. Neurological workup included video EEG, which captured seven events without EEG correlate and an unremarkable brain MRI. Neuropsychological evaluation indicated mild cognitive impairment due to epilepsy with deficits in processing speed, executive functioning, and confrontation naming with borderline to low average core visual and verbal abilities. The patient participated in manualized CBT for PNES. Results Treatment adaptations included extending treatment sessions from 12–19 sessions and including the patient’s sister. They read the chapters together and practiced strategies outside of session. She participated in helping him notice patterns of manifestations of fear and anger and their influence on somatic symptoms. Omission of treatment elements with higher cognitive demand (i.e., thought chart). Outcomes included increased awareness of emotions, triggers, and warnings but not episode reduction in the context of increased epileptic seizures. Conclusions Feasibility of treatment may be limited for individuals with mixed epileptic and NES episodes, particularly if there is cognitive impairment and difficulty differentiating between the two. Psychotherapeutic techniques that are concrete and behaviorally based will = be beneficial for individuals with cognitive impairment. Episode reduction in isolation is likely reductionistic when considering treatment effectiveness. Ability to self-manage episodes, quality of life, functional status, and self-efficacy are valuable markers of improvement.

B - 36 Investigating High-Definition Transcranial Direct Current Stimulation for Remediating Word Finding Difficulty in Civilians with a History of Chronic Traumatic Brain Injury: a Pilot Study

Abstract Objective Verbal-retrieval deficits often occur after traumatic brain injury (TBI), but no effective treatment is available. In this study, High-Definition Transcranial Direct Current Stimulation (HD-tDCS) was applied to examine its potential effects on cognitive, especially verbal-retrieval, performance in individuals with chronic TBI. Method Four adults (mean age 48 years; 3 females) with self-reported word-finding difficulty confirmed by objective measures following mild to moderate non-military TBIs sustained over a year ago underwent a double-blind, cross-over, randomized, sham-controlled trial. Each participant received 10 sessions of active HD-tDCS and sham stimulation over the superior medial frontal cortex. A battery of neuropsychological tests was administered including verbal-retrieval measures (i. e. letter fluency, category fluency, Boston Naming Test/BNT) at baseline, immediately, and 8 weeks post-treatment. Post-treatment performance was compared to baseline using 2-tailed paired t-tests. Results Improvements on letter fluency were observed between baseline and immediate assessments post active HD-tDCS, approaching statistical significance (p = 0.076, Cohen’s d = 0.957, 7.5 ± 5.7 more items). No immediate effects with sham HD-tDCS (p > 0.10, 1.5 ± 3.5 more items) and no sustained effects (8 weeks after) were found with either active or sham HD-tDCS (ps > 0.10). Additionally, no significant changes were observed for category fluency or BNT (all ps > 0.10). Conclusion While our pilot study suggests a potential benefit for improved letter fluency immediately following active HD-tDCS compared to sham, the lack of sustained improvement after 8 weeks and the observed variability across different tests acknowledges the need for future larger-scale investigation across multiple cognitive domains.

A - 10 Selective Serotonin Reuptake Inhibitors Do Not Alter HD-tDCS Effects on Episodic Memory in Cognitively Impaired Older Adults

Abstract Objective High-Definition Transcranial Direct Current Stimulation (HD-tDCS) is a potential new intervention for mild cognitive impairment (MCI) and Alzheimer’s Dementia (ad) involving small doses of electrical stimulation. Prior studies suggest potential interactions with Selective Serotonin Reuptake Inhibitors (SSRIs) that could alter HD-tDCS’s effectiveness on cognitive outcomes. This study evaluated if SSRIs altered HD-tDCS response to episodic memory functioning in individuals with MCI and ad. Method Eighteen individuals (M age = 70.5; 27.8% female; 8 stable on SSRIs), 9 with MCI and 9 with ad, underwent ten 20-minute HD-tDCS sessions of 1 milliampere over the medial frontal cortex. Neuropsychological testing assessed learning and delayed recall for visual (Brief Visuospatial Memory Test-Revised) and verbal (Rey Auditory Verbal Learning Test or Hopkins Verbal Learning Test-Revised) episodic memory at baseline and immediately post-treatment. Linear regressions evaluated SSRI use as a predictor of post-treatment episodic memory performance controlling for baseline scores. Results Ten participants demonstrated improvement on at least one measure by 0.5 standard deviation (SD; 5 T-score points), with 5 showing 1 SD improvement. Eleven showed a decline by 0.5 SD on at least one measure, with 7 showing 1 SD decline. SSRI use did not significantly predict better or worse verbal learning (β = −4.285, p = 0.194), verbal delayed recall (β-0.408, p = 0.883), visual learning (β = −2.788, p = 0.405), and visual delayed recall (β = −6.673, p = 0.150) performance post-HD-tDCS. Conclusion Preliminary findings suggest SSRIs may not impact HD-tDCS outcomes in cognitively impaired older adults, specifically for episodic memory. These results may not translate to other neuropsychological domains; however, larger samples are needed for further investigation.

Analysis of the Dynamics of Cognitive Impairments and Expression of Caspase Cascade Genes in Preclinical Stages of Parkinsonism Modeled Using α-Synuclein Oligomers.

The behavioral effects of α-synuclein oligomers were studied at various times after its chronic intranasal administration to 75-day-old C57BL/6J mice in comparison with the dynamics of changes in the transcriptional activity of caspases genes (Casp9, Casp8, and Casp3) in the hippocampus, frontal cortex, and cerebellum. The negative effects of α-synuclein oligomers on exploratory activity and short-term memory in the novel object recognition test were most pronounced after 90 days from the end of administration, while after 1 and 270 days, partial compensation of the studied cognitive functions was observed. Analysis of the expression of caspase genes suggests that early compensatory mechanisms are associated with suppression of the effector caspase-3 gene expression along with increased activity of the genes encoding initiator caspases-9 and -8. Late compensation processes are associated with a decrease in the activity of initiator caspases in the frontal cortex and cerebellum.

Whole-head high-density diffuse optical tomography to map infant audio-visual responses to social and non-social stimuli

Abstract Infancy is a time of rapid brain development. High-density diffuse optical tomography (HD-DOT) is an optical neuroimaging method that maps changes in cortical haemoglobin concentration, a marker of functional brain activation. Recent years have seen a huge advance in wearable hardware for HD-DOT, however previous headgear has only been capable of sampling specific areas of the cortex. In this work, we aimed to develop headgear capable of sampling across the whole infant scalp surface and to conduct a proof-of-concept demonstration of whole-head HD-DOT in infants aged 5 to 7 months. We developed a whole-head infant implementation of the high-density LUMO design developed by Gowerlabs Ltd. (UK). HD-DOT data were collected from a cohort of infants (N = 16) during the presentation of a screen-based paradigm assessing social processing. Using whole-head HD-DOT, we mapped activity across the entirety of the optically-accessible cortex which far exceeds coverage achieved by previous infant optical neuroimaging methods. We found activity in temporal regions which corroborates previous research. Further, we mapped activity in regions outside those typically sampled in infant research using social processing paradigms, finding activation in regions across the occipital, parietal, and frontal cortices as well as an apparent inverted response in sensorimotor regions. Following this proof-of-concept, we envisage that whole-head HD-DOT will be applied to map the interaction between different regions of the brain, opening new avenues to map activity in the awake infant brain to better understand the trajectory of typical and atypical neurodevelopment.

Association of Compensatory Mechanisms in Prefrontal Cortex and Impaired Anatomical Correlates in Semantic Verbal Fluency: A Functional Near-Infrared Spectroscopy Study.

Semantic verbal fluency (SVF) engages cognitive functions such as executive function, mental flexibility, and semantic memory. Left frontal and temporal lobes, particularly the left inferior frontal gyrus (IFG), are crucial for SVF. This study investigates SVF and associated neural processing in older adults with mild SVF impairment and the relationship between structural abnormalities in the left IFG and functional activation during SVF in those individuals. Fifty-four elderly individuals with modest level of mild cognitive impairment whose global cognition were preserved to normal but exhibited mild SVF impairment were participated. Prefrontal oxyhemoglobin (HbO2) activation and frontal cortical thickness were collected from the participants using functional near-infrared spectroscopy (fNIRS) and brain MRI, respectively. We calculated the β coefficient of HbO2 activation induced by tasks, and performed correlation analysis between SVF induced HbO2 activation and cortical thickness in frontal areas. We observed increased prefrontal activation during SVF task compared to the resting and control task. The activation distinct to SVF was identified in the midline superior and left superior prefrontal regions (p<0.05). Correlation analysis revealed an inverse relationship between SVF-specific activation and cortical thickness in the left IFG, particularly in pars triangularis (r(54)=-0.304, p=0.025). The study contributes to understanding the relationship between reduced cortical thickness in left IFG and increased functional activity in cognitively normal individuals with mild SVF impairment, providing implications on potential compensatory mechanisms for cognitive preservation.