A MUCH debated question is whether sex differences exist in the functional organization of the brain for language1–4. A long-held hypothesis posits that language functions are more likely to be highly lateralized in males and to be represented in both cerebral hemispheres in females5,6, but attempts to demonstrate this have been inconclusive7–17. Here we use echo-planar functional magnetic resonance imaging18–21 to study 38 right-handed subjects (19 males and 19 females) during orthographic (letter recognition), phonological (rhyme) and semantic (semantic category) tasks. During phonological tasks, brain activation in males is lateralized to the left inferior frontal gyrus regions; in females the pattern of activation is very different, engaging more diffuse neural systems that involve both the left and right inferior frontal gyrus. Our data provide clear evidence for a sex difference in the functional organization of the brain for language and indicate that these variations exist at the level of phonological processing.

Sex differences in the functional organization of the brain for language

Steady-state evoked potentials can be recorded from the human scalp in response to auditory stimuli presented at rates between 1 and 200 Hz or by periodic modulations of the amplitude and/or frequency of a continuous tone. Responses can be objectively detected using frequency-based analyses. In waking subjects, the responses are particularly prominent at rates near 40 Hz. Responses evoked by more rapidly presented stimuli are less affected by changes in arousal and can be evoked by multiple simultaneous stimuli without significant loss of amplitude. Response amplitude increases as the depth of modulation or the intensity increases. The phase delay of the response increases as the intensity or the carrier frequency decreases. Auditory steady-state responses are generated throughout the auditory nervous system, with cortical regions contributing more than brainstem generators to responses at lower modulation frequencies. These responses are useful for objectively evaluating auditory thresholds, assessing suprathreshold hearing, and monitoring the state of arousal during anesthesia.

Human auditory steady-state responses.

IMPORTANCE Lower educational attainment is associated with a higher risk of dementia.
However, less clear is the extent to which other socioeconomic markers contribute to
dementia risk. 
OBJECTIVE To examine the relationship of education, wealth, and area-based deprivation
with the incidence of dementia over the last decade in England and investigate differences
between people born in different periods. 
DESIGN, SETTING, AND PARTICIPANTS Data from the English Longitudinal Study of Ageing, a
prospective cohort study that is representative of the English population, were used to
investigate the associations between markers of socioeconomic status (wealth quintiles and
the index of multiple deprivation) and dementia incidence. To investigate outcomes
associated with age cohorts, 2 independent groups were derived using a median split (born
between 1902-1925 and 1926-1943). 
MAIN OUTCOMES AND MEASURES Dementia as determined by physician diagnosis and the
Informant Questionnaire on Cognitive Decline in the Elderly. 
RESULTS A total of 6220 individuals aged 65 years and older enrolled in the study (median
[interquartile range] age at baseline, 73.2 [68.1-78.3] years; 3410 [54.8%] female). Of these,
463 individuals (7.4%) had new cases of dementia ascertained in the 12 years between
2002-2003 and 2014-2015. In the cohort born between 1926 and 1943, the hazard of
developing dementia was 1.68 times higher (hazard ratio [HR] = 1.68 [95%CI, 1.05-2.86]) for
those in the lowest wealth quintile compared with those in the highest quintile, independent
of education, index of multiple deprivation, and health indicators. Higher hazards were also
observed for those in the second-highest quintile of index of multiple deprivation (HR = 1.62
[95%CI, 1.06-2.46]) compared with those in the lowest (least deprived) quintile. 
CONCLUSIONS AND RELEVANCE In an English nationally representative sample, the incidence
of dementia appeared to be socioeconomically patterned primarily by the level of wealth.
This association was somewhat stronger for participants born in later years.

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Individual and Area-Based Socioeconomic Factors Associated With Dementia Incidence in England: Evidence From a 12-Year Follow-up in the English Longitudinal Study of Ageing.

Purpose of reviewMotion sickness remains bothersome in conventional transport and is an emerging hazard in visual information technologies. Treatment remains unsatisfactory but advances in brain imaging, neurophysiology, and neuropharmacology may provide insights into more effective drug and behavio

Pathophysiology and treatment of motion sickness

This Review develops a theoretical framework for the development and onset of vulnerability in later life based on the concept of reserves. We stress the advantages of using the concept of reserves in interdisciplinary life-course studies, compared with related concepts such as resources and capital. We enrich the definition of vulnerability as a lack of reserves and a reduced capacity of an individual to restore reserves. Two dimensions of reserves, originating from lifespan psychology and gerontology, are of particular importance: their constitution and sustainability by behaviours and interaction with the environment (the ‘use it or lose it’ paradigm) and the presence of thresholds, below which functioning becomes highly challenging. This heuristic approach reveals the potential for a conceptualization of reserves and is exemplified in an empirical illustration. Further interdisciplinary research based on the concept is needed. Cullati and colleagues propose a framework to understand vulnerability in later life as a product of biological, psychological, cognitive, emotional, economical and relational ‘reserves’ built up over a lifetime, which can be called on to buffer against or recover from adversity.

Development of reserves over the life course and onset of vulnerability in later life.

Introduction Mental rotation ability has an important role in human navigation and, together with other cognitive abilities such as processing speed, working memory, and attention, is crucial for aircraft navigation. In the human performance literature, mental rotation tasks have consistently yielded reports of gender differences favoring men. The aim of this study was to compare the gender difference measured in a specialized population of aviators vs. a matched population of nonpilots. Methods : Studied were 41 pilots (20 men and 21 women) and 38 nonpilots (20 men and 18 women) matched for age and education. Pilots were stratified for flying hours. Participants performed a mental rotation task (MRT) in which accuracy and response time were recorded, and also completed sense-of-direction (SOD) and spatial cognitive styles self-evaluation scales. Results Men had significantly smaller response time in the MRT (men 279.6 +/- 147.0 s, women 401.6 +/- 361.3) and greater SOD (men's score 49.1 +/- 8.6, women's score 46.6 +/- 7.8), but these differences were absent among pilots. A positive relationship was also identified between pilots' response times and their flight hours. Conclusion These data suggest that the effect of gender on the speed of cognitive spatial processing is absent in a population with aviation experience. Gender effects may be associated with a low spatial cognitive style, whereas in groups such as aviators, who are expected to have high spatial cognitive style, other factors such as experience may come into play.

Gender effects on mental rotation in pilots vs. nonpilots.

Cognitive reserve (CR) has been defined as the ability to optimize or maximize performance through differential recruitment of brain networks. In the present study, we aimed at providing evidence for a consistent brain network underpinning CR in healthy and pathological aging. To pursue this aim, we performed a coordinate-based meta-analysis of 17 functional magnetic resonance imaging studies on CR proxies in healthy aging, Alzheimer's disease (AD), and mild cognitive impairment (MCI). We found that different brain areas were associated with CR proxies in healthy and pathological aging. A wide network of areas, including medial and lateral frontal areas, that is, anterior cingulate cortex and dorsolateral prefrontal cortex, as well as precuneus, was associated with proxies of CR in healthy elderly patients. The CR proxies in patients with AD and amnesic-MCI were associated with activation in the anterior cingulate cortex. These results were discussed hypothesizing the existence of possible compensatory mechanisms in healthy and pathological aging.

https://journals.sagepub.com/doi/pdf/10.1177/1533317516653826

Cognitive Reserve in Healthy Aging and Alzheimer’s Disease: A Meta-Analysis of fMRI Studies

Introduction The coding of space as near and far is not only determined by arm-reaching distance, but is also dependent on how the brain represents the extension of the body space. Recent reports suggest that the dissociation between reaching and navigational space is not limited to perception and action but also involves memory systems. It has been reported that gender differences emerged only in adverse learning conditions that required strong spatial ability. Methods In this study we investigated navigational versus reaching memory in air force pilots and a control group without flight experience. We took into account temporal duration (working memory and long-term memory) and focused on working memory, which is considered critical in the gender differences literature. Results We found no gender effects or flight hour effects in pilots but observed gender effects in working memory (but not in learning and delayed recall) in the nonpilot population (Women's mean = 5.33; SD= 0.90; Men's mean = 5.54; SD= 0.90). We also observed a difference between pilots and nonpilots in the maintenance of on-line reaching information: pilots (mean = 5.85; SD=0.76) were more efficient than nonpilots (mean = 5.21; SD=0.83) and managed this type of information similarly to that concerning navigational space. In the navigational learning phase they also showed better navigational memory (mean = 137.83; SD=5.81) than nonpilots (mean = 126.96; SD=15.81) and were significantly more proficient than the latter group. Discussion There is no gender difference in a population of pilots in terms of navigational abilities, while it emerges in a control group without flight experience. We found also that pilots performed better than nonpilots. This study suggests that once selected, male and female pilots do not differ from each other in visuo-spatial abilities and spatial navigation.

Gender differences in navigational memory: pilots vs. nonpilots

Endogenous ovarian hormones as well as exogenous oestradiol and progesterone play an important role in cognitive processing. Specifically, these hormones play a role in different aspects of memory, both in terms of storage capacity and temporal duration of the mnemonic track. These hormones also have various effects on different types of memory (i.e., verbal, visuo-spatial, prospective). This study investigated the effects of hormones on topographic memory, a type of memory specifically needed to recall a pathway and to acquire spatial information about locations, distances, and directions. We compared 25 naturally cycling women (NCW) in two different cycling phases, the early follicular phase (4th - 5th days) and the mid-luteal phase (20th-21st days), with 26 women taking oral contraceptives (OC) tested in the active pill phase (20th to 21st day of OC cycle) and the inactive pill phase (2nd to 4th day of OC cycle). Both groups performed the Walking Corsi Test to assess topographic memory in their respective cycling phases. Women were instructed to learn an eight-step sequence path and recall the path five minutes later. We found that the two groups differed in terms of learning the 8-step sequence path; OC users were always better (4–5 days vs. 20–21 days) than NCW. No differences emerged in the delayed recall of the same path. As already observed in other memory domains (i.e., verbal memory, emotional memory), OC users showed an advantage in terms of topographic learning. Our results might be explained by hormonal mechanisms and may suggest the future application of OC in women with topographic disorders or visuo-spatial difficulties.

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Effects of oral contraceptives and natural menstrual cycling on environmental learning.

INTRODUCTION: Human navigation is a very complex ability that encompasses all four stages of human information processing (sensory input, perception/cognition, selection, and execution of an action), involving both cognitive and physical requirements. During flight, the pilot uses all of these stages and one of the most critical aspect is interference. In fact, spatial tasks competing for the same cognitive resource cause greater distraction from a concurrent task than another task that uses different resource modalities. METHODS: Here we compared and contrasted the performance of pilots and nonpilots of both genders performing increasingly complex navigational memory tasks while exposed to various forms of interference. We investigated the effects of four different sources of interference: motor, spatial motor, verbal, and spatial environment, focusing on gender differences. RESULTS: We found that flight experts perform better than controls (Pilots: 6.50 ± 1.29; Nonpilots: 5.45 ± 1.41). Furthermore, in the general population, navigational working memory is compromised only by spatial environmental interference (Nonpilots: 4.52 ± 1.50); female nonpilots were less able than male nonpilots. Also, the flight expert group showed the same interference, even if reduced (Pilots: 5.24 ± 0.92); moreover, we highlighted a complete absence of gender-related effects. DISCUSSION: Spatial environmental interference is the only interference producing a decrease in performance. Nevertheless, pilots are less affected than the general population. This is probably a consequence of the need to commit substantial cognitive resources to process spatial information during flight. Verde P, Boccia M, Colangeli S, Barbetti S, Nori R, Ferlazzo F, Piccolo F, Vitalone R, Lucertini E, Piccardi L. Domain-specific interference tests on navigational working memory in military pilots. Aerosp Med Hum Perform. 2016; 87(6):528-533. Language: en

Paola Verde

Papers

Gender effects on mental rotation in pilots vs. nonpilots.

Cognitive Reserve in Healthy Aging and Alzheimer’s Disease: A Meta-Analysis of fMRI Studies

Gender differences in navigational memory: pilots vs. nonpilots

Effects of oral contraceptives and natural menstrual cycling on environmental learning.

Domain-Specific Interference Tests on Navigational Working Memory in Military Pilots.