Optic nerve,superior colliculus,visual thalamus,and primary visual cortex of the northern elephant seal (Mirounga angustirostris) and California sea lion (Zalophus californianus)

The northern elephant seal (Mirounga angustirostris) and California sea lion (Zalophus californianus) are members of a diverse clade of carnivorous mammals known as pinnipeds. Pinnipeds are notable for their large, ape‐sized brains, yet little is known about their central nervous system. Both the northern elephant seal and California sea lion spend most of their lives at sea, but each also spends time on land to breed and give birth. These unique coastal niches may be reflected in specific evolutionary adaptations to their sensory systems. Here, we report on components of the visual pathway in these two species. We found evidence for two classes of myelinated fibers within the pinniped optic nerve, those with thick myelin sheaths (elephant seal: 9%, sea lion: 7%) and thin myelin sheaths (elephant seal: 91%, sea lion: 93%). In order to investigate the architecture of the lateral geniculate nucleus, superior colliculus, and primary visual cortex, we processed brain sections from seal and sea lion pups for Nissl substance, cytochrome oxidase, and vesicular glutamate transporters. As in other carnivores, the dorsal lateral geniculate nucleus consisted of three main layers, A, A1, and C, while each superior colliculus similarly consisted of seven distinct layers. The sea lion visual cortex is located at the posterior side of cortex between the upper and lower banks of the postlateral sulcus, while the elephant seal visual cortex extends far more anteriorly along the dorsal surface and medial wall. These results are relevant to comparative studies related to the evolution of large brains.     

A review of the verbal and visual memory impairments in children with foetal alcohol spectrum disorders

Background: Children with Foetal Alcohol Spectrum Disorders (FASD) have significant impairments in memory, negatively affecting academics and daily functioning.

Primary objective: To review published research on: (1) verbal and visual-spatial memory in children with FASD or prenatal alcohol exposure (PAE); (2) animal research on the impact of PAE on memory; and (3) brain areas involved in memory that are affected by PAE.

Main outcomes: Verbal memory is one of the main areas of memory affected by gestational alcohol exposure, specifically in encoding and retrieving information. Spatial memory has emerged as a dominant deficit in individuals with FASD, consistent in children, adolescents and adults. There are regions of the brain more typically affected by PAE, which have ties to memory functioning. Animal research has confirmed the presence of impacts to key brain regions involved in memory functioning for those affected by PAE.

Conclusion: Memory deficits are a prevalent finding in individuals with PAE. Research in this area is complicated by small sample sizes, difficulty linking animal research to human application and lack of effective connection between existing memory theory and functional memory testing in FASD. New research has shown that there are implications for memory and learning amelioration in children with FASD.     

Early stages (P100) of face perception in humans as measured with event-related potentials (ERPs)

Summary. According to current ERP literature, face specific activity is reflected by a negative component over the inferior occipito-temporal cortex between 140 and 180 ms after stimulus onset (N170). A recently published study (Liu et al., 2002) using magnetoencephalography (MEG) clearly indicated that a face-selective component can be observed at 100 ms (M100) which is about 70 ms earlier than reported in most previous studies. Here we report these early differences at 107 ms between the ERPs of faces and buildings over the occipito-temporal cortex using electroencephalography. To exclude contrast differences as the main factor for this P100 differences we replicated this study using pictures of faces and scrambled faces. Both studies indicated that face processing starts already at ∼100 ms with an initial stage which can be measured not only with MEG but also with ERPs.     

Amygdalofugal and amygdalopetal connections with modality-specific visual cortical areas in macaques (Macaca fuscata, M. mulatta, and M. fascicularis)

The origins and terminations of the amygdaloid connections with the modality-specific visual cortical areas TEa (anterior TE area), TEp (posterior TE area), TEO, V4, V2, MST (medial superior temporal visual area), MT (middle temporal visual area), and V1 were studied in macaques. These were compared with the amygdaloid connections of a vision-related polysensory area TG by making cortical injections of horseradish peroxidase (HRP) and incubating the sections with tetramethylbenzidine (TMB) as the chromogen. Both areas TEa and TEp receive a major projection from the lateral basal nucleus and a minor one from the accessory basal nucleus of the amygdaloid complex, whereas these areas send a major projection to the lateral nucleus and a minor one to the lateral basal nucleus. Areas TEO, V4, V2, MST, MT, and V1 receive projections only from the lateral basal nucleus; none of them project to any amygdaloid nucleus. Thus, the amygdalofugal projections are more widespread and more complex than the amygdalopetal projections. These findings indicate that the connections between the amygdaloid nuclei and the visual areas are generally nonreciprocal and underlie the importance of a feedback mechanism from the amygdala to the visual cortical areas in visual information processing. There appears to be a caudorostral (occipitotemporal) gradient in the distribution and density of the amygdaloid projections, which become progressively more widespread and heavier among the progressively more rostral visual areas (from area V1 to area TEa). The amygdaloid connections with area TG are distinctly different from the connections with the visual areas. Area TG is reciprocally connected mainly with the periamygdaloid cortex, and with the lateral, accessory basal, and medial basal nuclei of the amygdala as well.     

Preserved cortical asymmetry despite thinner cortex in children and adolescents with prenatal alcohol exposure and associated conditions

Prenatal alcohol exposure (PAE) is associated with reduced overall brain volume. Although this has been reported consistently across studies, the status of cortical thickness after PAE is more variable. The cortex is asymmetric in typical controls, but it is unclear whether the left and right counter parts of the cortical gray matter are unevenly influenced in postpartum brain development after PAE. Brain MRI was acquired in a newly recruited sample of 157 participants (PAE: N = 78, 5.5–18.9 years, 40 females and controls: N = 79, 5.8–18.5 years, 44 females) across four Canadian sites in the NeuroDevNet project. The PAE group had other confounds such as psychiatric co‐morbidity, different living environment, and so on, not present in the control group. In agreement with previous studies, the volumes of all brain structures were reduced in PAE compared to controls, including gray and white matter of cerebrum and cerebellum, and all deep gray matter including the hippocampus, amygdala, thalamus, caudate, putamen, and pallidum. The PAE group showed reductions in global and regional cortical thickness, while the pattern and degree of cortical thickness asymmetry were preserved in PAE participants with the greatest rightward asymmetry in the lateral parietal lobe and the greatest leftward asymmetry in the lateral frontal cortex. This persistent asymmetry reflects that the homologous left and right cortical regions followed typical relative developmental patterns in the PAE group despite being thinner bilaterally than controls. Hum Brain Mapp 39:72–88, 2018. © 2017 Wiley Periodicals, Inc.     

Putting Fetal Alcohol Spectrum Disorder (FASD) on the Map in New Zealand: A Review of Health,Social, Political,Justice and Cultural Developments

The damaging effects of alcohol intake have long been recognised as an issue for New Zealand society since the introduction of alcohol by early settlers. In the mid-1990s, New Zealand began to acknowledge the distinct set of impairments that result from prenatal alcohol exposure that is now known as fetal alcohol spectrum disorder (FASD), which affects all facets of an individual's life, including having individual impairments as well as secondary disabilities arising from those impairments. In New Zealand, a collaborative, multidisciplinary and multiagency approach has been necessary in order to offer the best support for individuals and families who are living with FASD. In this article, the developments within New Zealand's health, justice, social and cultural sectors are traced and the work of many individual trailblazers who have put FASD on the map is acknowledged. The story of putting FASD on the map in New Zealand is one of determination, hope and opportunity, as well as recognition that there is still a long way to go.     

Distribution of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate-type glutamate receptor subunits (GluR2/3) along the ventral visual pathway in the monkey

By using immunohistochemical methods, we examined the distribution of cells expressing subunits of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)-selective glutamate receptors (GluR2/3) in the cortical areas of the occipitotemporal pathway in monkeys. GluR2/3-immunoreactive (-ir) cells were primarily pyramidal cells; this category, however, also included large stellate cells in layer IVB of the striate cortex (V1) and fusiform cells in layer VI of all the areas examined. GluR2/3 immunoreactivity differed among the areas in laminar distribution and intensity. In V1, GluR2/3-ir cells were identified mainly in layers II, III, IVB, and VI. The prestriate areas V2 and V4 and the inferior temporal areas TEO and TE contained GluR2/3-ir cells in layers II, III, and VI. In the TE, GluR2/3-ir cells were also abundant in layer V. In area 36 of the perirhinal cortex, neurons in layers II, III, V, and VI were labeled in a similar manner to the TE labeling, but with greater staining intensity and numbers, especially in layer V. Thus, GluR2/3 immunoreactivity increased rostrally along the pathway. Within V1 and V2, cells strongly stained for GluR2/3 formed clusters that colocalized with cytochrome oxidase (CO)-rich regions. These distinct laminar and regional distribution patterns of GluR2/3 expression may contribute to the specific physiological properties of neurons within various visual areas and compartments.     

Autism spectrum traits in children and adolescents with obsessive-compulsive disorder (OCD)

OBJECTIVE: Assess the prevalence of autistic traits (AST) in pediatric obsessive-compulsive disorder (OCD) and relate them to OCD co-morbidity and compare them with published normative data. METHODS: Pediatric patients with obsessive-compulsive disorder (n=109) according to the DSM-IV were studied using parent ratings of the Autistic Symptom/Syndrome Questionnaire to assess AST symptoms as a continuous rather than categorical trait. The KSADS, a semi-structured psychiatric interview, was used for the psychiatric diagnostic evaluation. Also, the Children's Yale-Brown Obsessive-Compulsive Scale was used to assess OCD severity and other clinical features. RESULTS: AST was common among our patients. Symptom scores were highest in cases with co-morbid Autistic Spectrum Disorders, but cases with other co-morbidities as tics/Tourette and attention/behavioral disorders also scored higher. All sub-groups, including OCD without these co-morbidities scored higher than the Swedish normative group. Using ANOVA, co-morbid ASD and tics/Tourette (plus a term for gender by tic interaction indicating that girls with tics scored high, otherwise low) and pathological doubt contributed (R2=.41) to the AST-traits, while OCD severity and co-morbid anxiety- and depressive disorders did not. CONCLUSION: AST traits are prevalent in OCD and seem to be intricately associated with the co-morbidities as well as the OCD syndrome itself. The findings might have implication for our nosological understanding of OCD which currently is discussed.     

Commentary: Demand Avoidance Phenomena,a manifold issue? Intolerance of uncertainty and anxiety as explanatory frameworks for extreme demand avoidance in children and adolescents – a commentary on Stuart et al. (2020)

Demand Avoidance Phenomena (DAP) is a neutral term for Pathological Demand Avoidance, which is sometimes conceptualised as an autism subtype. There is much ongoing controversy around the construct. In this commentary, I attempt to contextualise the recent article, Intolerance of Uncertainty and anxiety (Stuart et al., 2019) within wider discourses. This discussion provides tentative support for monotropism autism theory and the growing body of research indicating that DAP may not be developmentally persistent (a high rate of persons not meeting clinical threshold into adulthood). Going forward I would suggest that Stuart and colleagues' research should be replicated, in order to add to the DAP literature.     

Electrified minds: Transcranial direct current stimulation (tDCS) and Galvanic Vestibular Stimulation (GVS) as methods of non-invasive brain stimulation in neuropsychology—A review of current data and future implications

Transcranial direct current stimulation (tDCS) is a noninvasive, low-cost and easy-to-use technique that can be applied to modify cerebral excitability. This is achieved by weak direct currents to shift the resting potential of cortical neurons. These currents are applied by attaching two electrodes (usually one anode and one cathode) to distinct areas of the skull. Galvanic Vestibular Stimulation (GVS) is a variant of tDCS where the electrodes are attached to the mastoids behind the ears in order to stimulate the vestibular system. tDCS and GVS are safe when standard procedures are used. We describe the basic physiological mechanisms and application of these procedures. We also review current data on the effects of tDCS and GVS in healthy subjects as well as clinical populations. Significant effects of such stimulation have been reported for motor, visual, somatosensory, attentional, vestibular and cognitive/emotional function as well as for a range of neurological and psychiatric disorders. Moreover, both techniques may induce neuroplastic changes which make them promising techniques in the field of neurorehabilitation. A number of open research questions that could be addressed with tDCS or GVS are formulated in the domains of sensory and motor processing, spatial and nonspatial attention including neglect, spatial cognition and body cognition disorders, as well as novel treatments for various neuropsychological disorders. We conclude that the literature suggests that tDCS and GVS are exciting and easily applicable research tools for neuropsychological as well as clinical-therapeutic investigations.     

Decreased resting-state alpha peak frequency in children and adolescents with fetal alcohol spectrum disorders or prenatal alcohol exposure

Prenatal alcohol exposure (PAE) can result in long-lasting changes to physical, behavioral, and cognitive functioning in children. PAE might result in decreased white matter integrity, corticothalamic tract integrity, and alpha cortical oscillations. Previous investigations of alpha oscillations in PAE/fetal alcohol spectrum disorder (FASD) have focused on average spectral power at specific ages; therefore, little is known about alpha peak frequency (APF) or its developmental trajectory making this research novel. Using resting-state MEG data, APF was determined from parietal/occipital regions in participants with PAE/FASD or typically developing controls (TDC). In total, MEG data from 157 infants, children, and adolescents ranging in age from 6 months to 17 years were used, including 17 individuals with PAE, 61 individuals with an FASD and 84 TDC. In line with our hypothesis, we found that individuals with PAE/FASD had significantly reduced APF relative to TDC. Both age and group were significantly related to APF with differences between TDC and PAE/FASD persisting throughout development. We did not find evidence that sex or socioeconomic status had additional impact on APF. Reduced APF in individuals with an FASD/PAE may represent a long-term deficit and demonstrates the detrimental impact prenatal alcohol exposure can have on neurophysiological processes.