Frontoparietal Tracts Linked to Lateralized Hand Preference and Manual Specialization.

Humans show a preference for using the right hand over the left for tasks and activities of everyday life. While experimental work in non-human primates has identified the neural systems responsible for reaching and grasping, the neural basis of lateralized motor behavior in humans remains elusive. The advent of diffusion imaging tractography for studying connectional anatomy in the living human brain provides the possibility of understanding the relationship between hemispheric asymmetry, hand preference, and manual specialization. In this study, diffusion tractography was used to demonstrate an interaction between hand preference and the asymmetry of frontoparietal tracts, specifically the dorsal branch of the superior longitudinal fasciculus, responsible for visuospatial integration and motor planning. This is in contrast to the corticospinal tract and the superior cerebellar peduncle, for which asymmetry was not related to hand preference. Asymmetry of the dorsal frontoparietal tract was also highly correlated with the degree of lateralization in tasks requiring visuospatial integration and fine motor control. These results suggest a common anatomical substrate for hand preference and lateralized manual specialization in frontoparietal tracts important for visuomotor processing.

Cost-Effective Technologies to Study the Arctic Ocean Environment †.

The Arctic region is known to be severely affected by climate change, with evident alterations in both physical and biological processes. Monitoring the Arctic Ocean ecosystem is key to understanding the impact of natural and human-induced change on the environment. Large data sets are required to monitor the Arctic marine ecosystem and validate high-resolution satellite observations (e.g., Sentinel), which are necessary to feed climatic and biogeochemical forecasting models. However, the Global Observing System needs to complete its geographic coverage, particularly for the harsh, extreme environment of the Arctic Region. In this scenario, autonomous systems are proving to be valuable tools for increasing the resolution of existing data. To this end, a low-cost, miniaturized and flexible probe, ArLoC (Arctic Low-Cost probe), was designed, built and installed on an innovative unmanned marine vehicle, the PROTEUS (Portable RObotic TEchnology for Unmanned Surveys), during a preliminary scientific campaign in the Svalbard Archipelago within the UVASS project. This study outlines the instrumentation used and its design features, its preliminary integration on PROTEUS and its test results.

A pilot study on the use of interferon beta-1a in early Alzheimer's disease subjects.

Despite the fact that multiple sclerosis (MS) and Alzheimer's disease (AD) share common neuroimmunological features, interferon beta 1a (IFNß1a), the well-established treatment for the prevention of disease progression and cognitive decline in MS patients, has never been used in AD. We evaluated the safety and efficacy of IFNß1a in subjects affected by mild-to-moderate AD in a double-blind, randomized, placebo-controlled, multicenter pilot study. Forty-two early Alzheimer's patients were randomized to receive either a 22 mcg subcutaneous injection of IFNß1a or placebo three times per week. A treatment period of 28 weeks was followed by 24 weeks of observation. IFNß1a was well tolerated and adverse events were infrequent and mild to moderate. Although not statistically significant, a reduction in disease progression during follow-up was measured in IFNß1a-treated patients by the Alzheimer's Disease Assessment Scale cognitive subscale. Interestingly, the treatment group showed significant improvements in the Instrumental Activities of Daily Living and Physical Self-maintenance Scale. This study suggests that IFNß1a is safe and well tolerated in early AD patients, and its possible beneficial role should be further investigated in larger studies.

Semantic interference mechanisms on long-term visual memory and their eye-movement signatures in mild cognitive impairment.

OBJECTIVE: Long-term visual memory representations, measured by recognition performance, degrade as a function of semantic interference, and their strength is related to eye-movement responses. Even though clinical research has examined interference mechanisms in pathological cognitive aging and explored the diagnostic potential of eye-movements in this context, little is known about their interaction in long-term visual memory. METHOD: An eye-tracking study compared a Mild Cognitive Impaired group with healthy adults. Participants watched a stream of 129 naturalistic images from different semantic categories, presented at different frequencies (1, 6, 12, 24) to induce semantic interference (SI), then asked in a 2-Alternative Forced Choice paradigm to verbally recognize the scene they remembered (old/novel). RESULTS: Recognition accuracy of both groups was negatively impacted by SI, especially in healthy adults. A wider distribution of overt attention across the scene predicted better recognition, especially by the Mild Cognitive Impaired (MCI) participants, although these fixation patterns were influenced by SI. MCI compensated the detrimental effect of SI by focusing overt attention during encoding and so accruing distinctive details of the scene. During recognition, MCI participants widened overt attention to boost retrieval. Independently of the group: (a) the re-instatement of fixations indicated a more successful recall and increased as a function of SI; and (b) attending visually salient regions negatively impacted on recognition accuracy, although the reliance on such regions grew as SI increased. CONCLUSIONS: Effects of SI on long-term memory were reduced in MCI participants. They used different oculomotor strategies compared to healthy adults to compensate for its detrimental effects. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Low-Frequency Repetitive Transcranial Magnetic Stimulation of the Right Dorsolateral Prefrontal Cortex Enhances Recognition Memory in Alzheimer's Disease.

BACKGROUND: The lack of effective pharmacological or behavioral interventions for memory impairments associated with Alzheimer's disease (AD) emphasizes the need for the investigation of approaches based on neuromodulation. OBJECTIVE: This study examined the effects of inhibitory repetitive transcranial magnetic stimulation (rTMS) of prefrontal cortex on recognition memory in AD patients. METHODS: In a first experiment, 24 mild AD patients received sham and real 1Hz rTMS over the left and right dorsolateral prefrontal cortex (DLPFC), in different sessions, between encoding and retrieval phases of a non-verbal recognition memory task. In a second experiment, another group of 14 AD patients underwent sham controlled repeated sessions of 1Hz rTMS of the right DLPFC across a two week treatment. Non-verbal recognition memory task was performed at baseline, at the end of the two weeks period and at a follow up of 1 month. RESULTS: Right real rTMS significantly improved memory performance compared to right sham rTMS (p = 0.001). Left real rTMS left the memory performance unchanged as compared with left sham rTMS (p = 0.46). The two sham conditions did not differ between each other (p = 0.24). In the second experiment, AD patients treated with real rTMS showed an improvement of memory performance at the end of the two weeks treatment (p = 0.0009), that persisted at 1-month follow-up (p = 0.002). CONCLUSION: These findings provide evidence that inhibitory rTMS over the right DLPFC can improve recognition memory function in AD patients. They also suggest the importance of a new approach of non-invasive brain stimulation as a promising treatment in AD.

Cognitive findings in spinocerebellar ataxia type 2: relationship to genetic and clinical variables.

Several authors have recently reported a broad cognitive impairment in autosomal dominant cerebellar ataxias (ADCAs) patients. However, only a few studies on neuropsychological features in spinocerebellar ataxia type 2 (SCA2) patients are present in the current literature. The aim of this study is to evaluate the cognitive impairment in a wide sample of SCA2 patients and to verify the role of different disease-related factors (age of onset, disease duration, and clinical severity) on intellectual abilities. We administered a battery of neuropsychological tests assessing handedness, attention, short- and long-term verbal and visuo-spatial memory, executive functions, constructive abilities, general intellectual abilities and depression to 18 SCA2 patients belonging to eight families who came to our observation. Evidence of impaired verbal memory, executive functions and attention was found. The cognitive status was partially related to clinical severity rather than to disease duration or age at onset of symptoms. We partially confirmed data on cognitive defects already reported by others but we also found defective attention skills as well as significant lower performances in a nonverbal intelligence task.

Relationship between clinical variables and cognitive performances in migraineurs with and without aura.

Conflicting data on cognitive defects in migraine could be explained by differences in the clinical variables of the populations studied. We investigated 21 patients with migraine with aura and 24 with migraine without aura, diagnosed according to the International Headache Society criteria. The patients were submitted to a comprehensive battery of neuropsychological tests and grouped according to attack frequency and side of pain. Attack frequency was not associated with significant differences in any of the tasks, while location of pain was found to be significantly related to poorer performance on both the immediate and delayed recall of Rey Complex Figure in migraineurs both with and without aura, and a significant relationship between side of pain and number of clusters in the second trial of California Verbal Learning Test was found only in migraine with aura patients. The finding of worse performances in patients with right-sided pain seems to support a right hemisphere dysfunction hypothesis.

Traumatic brain injury and the frontal lobes: what can we gain with diffusion tensor imaging?

Traumatic brain injury (TBI) is a leading cause of death in the young population and long-term disability in relation to pervasive cognitive-behavioural disturbances that follow frontal lobe damage. To date, emphasis has been placed primarily on the clinical correlates of frontal cortex damage, whilst identification of the contribution of subjacent white matter lesion is less clear. Our poor understanding of white matter pathology in TBI is primarily due to the low sensitivity of conventional neuroimaging to identify pathological changes in less severe traumatic injury and the lack of methods to localise white matter pathology onto individual frontal lobe connections. In this paper we focus on the potential contribution of diffusion tensor imaging (DTI) to TBI. Our review of the current literature supports the conclusion that DTI is particularly sensitive to changes in the microstructure of frontal white matter, thus providing a valuable biomarker of the severity of traumatic injury and prognostic indicator of recovery of function. Furthermore we propose an atlas approach to TBI to map white matter lesions onto individual tracts. In the cases presented here we showed a direct correspondence between the clinical manifestations of the patients and the damage to specific white matter tracts. We are confident that in the near future the application of DTI to TBI will improve our understanding of the complex and heterogeneous clinical symptomatology which follows a TBI, especially mild and moderate head injury, which still represents 70-80% of all clinical population.

Enhancing memory performance with rTMS in healthy subjects and individuals with Mild Cognitive Impairment: the role of the right dorsolateral prefrontal cortex.

A debated question in the literature is the degree of anatomical and functional lateralization of the executive control processes sub-served by the dorsolateral prefrontal cortex (DLPFC) during recognition memory retrieval. We investigated if transient inhibition and excitation of the left and right DLPFC at retrieval by means of repetitive transcranial magnetic stimulation (rTMS) modulate recognition memory performance in 100 healthy controls (HCs) and in eight patients with Mild Cognitive Impairment (MCI). Recognition memory tasks of faces, buildings, and words were used in different experiments. rTMS-inhibition of the right DLPFC enhanced recognition memory in both HCs and MCIs. rTMS-excitation of the same region in HCs deteriorated memory performance. Inhibition of the right DLPFC could modulate the excitability of a network of brain regions, in the ipsilateral as well as in the contralateral hemisphere, enhancing function in HCs or restoring an adaptive equilibrium in MCI.

Cessation versus continuation of galantamine treatment after 12 months of therapy in patients with Alzheimer's disease: a randomized, double blind, placebo controlled withdrawal trial.

Galantamine improved symptoms in Alzheimer's disease (AD) patients after 5 to 6 months of treatment. To examine long-term outcomes, this study assessed if continuing of galantamine treatment beyond 12 months delayed further cognitive deterioration. It consisted of two phases: an open label (OL) phase (12 months), followed by a double blind, randomized, placebo controlled withdrawal phase (up to 24 months). Subjects with mild to moderate AD were included in the study and titrated up to 16 mg/day of galantamine. Subjects were eligible to enter the double blind phase if a cognitive decline of <4 points on AD Assessment Scale-cognitive subscale (ADAS-cog)/11 was recorded at the end of the OL phase. The differences between galantamine and placebo in time to dropout were estimated using the Cox proportional hazard model. 47.4% of galantamine and 31.7% of placebo subjects completed the double blind phase. Placebo subjects were more likely to discontinue prematurely than galantamine subjects for any reason (hazard ratio [HR] 1.76, 95% confidence interval [CI] 1.10-2.81, p = 0.02), or lack of efficacy (HR 1.80, 95% CI 1.02-3.18, p = 0.04); no statistically significant difference was seen for a change in ADAS-cog ≥ 4 between treatment groups (HR 1.66, 95% CI 0.78-3.54, p = 0.19). Subjects who responded to 12 months of galantamine treatment benefited from continued drug therapy for up to 36 months. Galantamine was effective in delaying time to cognitive deterioration in subjects with mild to moderate AD. Treatment was generally safe and well tolerated.

Cognitive findings after transient global amnesia: role of prefrontal cortex.

The aim of this study is to verify, after recovery, the presence of specific patterns of cognitive dysfunctions in Transient Global Amnesia (TGA). Fourteen patients with the diagnosis of TGA were submitted to a battery of neuropsychological tests and compared to a matched control group. We found significant qualitative and quantitative differences between TGA patients and controls in the California Verbal Learning Test (CLVT) and Rey-Osterrieth Complex Figure Test. Our data support the presence of selective cognitive dysfunctions after the clinical recovery. Moreover, for Verbal Fluency, Digit Span Backward, and Number of Clusters in the CVLT short-term memory test, the relation resulted as positively related with the temporal interval from the TGA episode. Reduction of categorical learning, attention, and qualitative alterations of spatial strategy seem to postulate a planning defect due to a prefrontal impairment.