Dissociations in cognitive memory: the syndrome of developmental amnesia

The dearth of studies on amnesia in children has led to the assumption that when damage to the medial temporal lobe system occurs early in life, the compensatory capacity of the immature brain rescues memory functions. An alternative view is that such damage so interferes with the development of learning and memory that it results not in selective cognitive impairments but in general mental retardation. Data will be presented to counter both of these arguments. Results obtained from a series of 11 amnesic patients with a history of hypoxic ischaemic damage sustained perinatally or during childhood indicate that regardless of age at onset of hippocampal pathology, there is a pronounced dissociation between episodic memory, which is severely impaired, and semantic memory, which is relatively preserved. A second dissociation is characterized by markedly impaired recall and relatively spared recognition leading to a distinction between recollection-based versus familiarity-based judgements. These findings are discussed in terms of the locus and extent of neuropathology associated with hypoxic ischaemic damage, the neural basis of 'remembering' versus 'knowing', and a hierarchical model of cognitive memory.     

Identification of FOXP2 truncation as a novel cause of developmental speech and language deficits

FOXP2, the first gene to have been implicated in a developmental communication disorder, offers a unique entry point into neuromolecular mechanisms influencing human speech and language acquisition. In multiple members of the well-studied KE family, a heterozygous missense mutation in FOXP2 causes problems in sequencing muscle movements required for articulating speech (developmental verbal dyspraxia), accompanied by wider deficits in linguistic and grammatical processing. Chromosomal rearrangements involving this locus have also been identified. Analyses of FOXP2 coding sequence in typical forms of specific language impairment (SLI), autism, and dyslexia have not uncovered any etiological variants. However, no previous study has performed mutation screening of children with a primary diagnosis of verbal dyspraxia, the most overt feature of the disorder in affected members of the KE family. Here, we report investigations of the entire coding region of FOXP2, including alternatively spliced exons, in 49 probands affected with verbal dyspraxia. We detected variants that alter FOXP2 protein sequence in three probands. One such variant is a heterozygous nonsense mutation that yields a dramatically truncated protein product and cosegregates with speech and language difficulties in the proband, his affected sibling, and their mother. Our discovery of the first nonsense mutation in FOXP2 now opens the door for detailed investigations of neurodevelopment in people carrying different etiological variants of the gene. This endeavor will be crucial for gaining insight into the role of FOXP2 in human cognition.     

The Effects of Magnesium and Zinc Co-Supplementation on Biomarkers of Inflammation and Oxidative Stress,and Gene Expression Related to Inflammation in Polycystic Ovary Syndrome: a Randomized Controlled Clinical Trial

Magnesium and zinc are known to exert multiple beneficial effects including anti-inflammatory and antioxidant actions. To our knowledge, data on the effects of magnesium and zinc co-supplementation on biomarkers of inflammation and oxidative stress and gene expression related to inflammation in subjects of polycystic ovary syndrome (PCOS) are scarce. This study was conducted to evaluate the effects of magnesium and zinc co-supplementation on biomarkers of inflammation and oxidative stress and gene expression related to inflammation in subjects with PCOS. This randomized double-blind, placebo-controlled trial was conducted among 60 subjects with PCOS diagnosed according to the Rotterdam criteria, aged 18–40 years old. Participants were randomly assigned into two groups to take either 250 mg of magnesium oxide plus 220 mg of zinc sulfate (containing 50 mg zinc) supplements (n?=?30) or placebo (n?=?30) twice a day for 12 weeks. Biomarkers of inflammation and oxidative stress were assessed at baseline and at end of treatment. Gene expression related to inflammatory cytokines was assessed in peripheral blood mononuclear cells (PBMCs) of PCOS women with RT-PCR method. After the 12-week intervention, compared with the placebo, magnesium and zinc co-supplementation significantly decreased serum high-sensitivity C-reactive protein (hs-CRP) (??1.6?±?2.4 vs. +?0.1?±?0.7 mg/L, P?=?0.001) and protein carbonyl (PCO) (??0.14?±?0.28 vs. +?0.02?±?0.07 mmol/mg protein, P?=?0.002) and significantly increased plasma total antioxidant capacity (TAC) levels (+?60.7?±?69.4 vs. ??1.5?±?141.5 mmol/L, P?=?0.03). Results of RT-PCR demonstrated that compared with the placebo, magnesium and zinc co-supplementation downregulated gene expression of interleukin-1 (IL-1) (P?=?0.007) and tumor necrosis factor alpha (TNF-α) (P?=?0.03) in PBMCs of subjects with PCOS. Overall, magnesium and zinc co-supplementation, compared with the placebo, for 12 weeks among PCOS women had beneficial effects on serum hs-CRP, plasma PCO, TAC, and gene expression of IL-1 and TNF-α. Clinical trial registration number: http://www.irct.ir: IRCT201706075623N121.     

Investigating individual differences in brain abnormalities in autism

Autism is a psychiatric syndrome characterized by impairments in three domains: social interaction, communication, and restricted and repetitive behaviours and interests. Recent findings implicate the amygdala in the neurobiology of autism. In this paper, we report the results of a series of novel experimental investigations focusing on the structure and function of the amygdala in a group of children with autism. The first section attempts to determine if abnormality of the amygdala can be identified in an individual using magnetic resonance imaging in vivo. Using single-case voxel-based morphometric analyses, abnormality in the amygdala was detected in half the children with autism. Abnormalities in other regions were also found. In the second section, emotional modulation of the startle response was investigated in the group of autistic children. Surprisingly, there were no significant differences between the patterns of emotional modulation of the startle response in the autistic group compared with the controls.     

The primate hippocampus: ontogeny, early insult and memory

Recent evidence suggests that in primates, as in rodents, the hippocampus shows a developmental continuum that affects memory abilities from infancy to adulthood. In primates relatively few hippocampal-dependent abilities (e.g. some aspects of recognition memory) are present in early infancy, whereas others (e.g. relational memory) begin to show adult-like characteristics around 2 years of age in monkeys and 5-7 years in humans. Profound and persistent memory loss resulting from insult to the hippocampus in infancy becomes evident in everyday behavior only later in childhood. This pattern of results suggests a maturational gradient within the medial temporal lobe memory system, with most abilities crucially dependent upon the hippocampus emerging in later stages of development, supporting a model of hierarchical organization of memory within the medial temporal lobe.     

The impact of therapy for childhood acute lymphoblastic leukaemia on intelligence quotients; results of the risk-stratified randomized central nervous system treatment trial MRC UKALL XI

Background

The MRC UKALLXI trial tested the efficacy of different central nervous system (CNS) directed therapies in childhood acute lymphoblastic leukaemia (ALL). To evaluate morbidity 555/1826 randomised children underwent prospective psychological evaluations. Full Scale, verbal and performance IQs were measured at 5 months, 3 years and 5 years. Scores were compared in; (1) all patients (n = 555) versus related controls (n = 311), (2) low-risk children (presenting white cell count (WCC) < 50 × 10⁹/l) randomised to intrathecal methotrexate (n = 197) versus intrathecal and high-dose intravenous methotrexate (HDM) (n = 202), and (3) high-risk children (WCC ≥ 50 × 10⁹/l, age ≥ 2 years) randomised to HDM (n = 79) versus cranial irradiation (n = 77).

Results

There were no significant differences in IQ scores between the treatment arms in either low- or high-risk groups. Despite similar scores at baseline, results at 3 and 5 years showed a significant reduction of between 3.6 and 7.3 points in all three IQ scores in all patient groups compared to controls (P < 0.002) with a higher proportion of children with IQs < 80 in the patient groups (13% vs. 5% at 3 years p = 0.003).

Conclusion

Children with ALL are at risk of CNS morbidity, regardless of the mode of CNS-directed therapy. Further work needs to identify individuals at high-risk of adverse CNS outcomes.

Trial registration

ISRCTN: ISRCTN16757172     

FOXP2 and the neuroanatomy of speech and language

That speech and language are innate capacities of the human brain has long been widely accepted, but only recently has an entry point into the genetic basis of these remarkable faculties been found. The discovery of a mutation in FOXP2 in a family with a speech and language disorder has enabled neuroscientists to trace the neural expression of this gene during embryological development, track the effects of this gene mutation on brain structure and function, and so begin to decipher that part of our neural inheritance that culminates in articulate speech.     

The SPCH1 region on human 7q31: genomic characterization of the critical interval and localization of translocations associated with speech and language disorder

The KE family is a large three-generation pedigree in which half the members are affected with a severe speech and language disorder that is transmitted as an autosomal dominant monogenic trait. In previously published work, we localized the gene responsible (SPCH1) to a 5.6-cM region of 7q31 between D7S2459 and D7S643. In the present study, we have employed bioinformatic analyses to assemble a detailed BAC-/PAC-based sequence map of this interval, containing 152 sequence tagged sites (STSs), 20 known genes, and >7.75 Mb of completed genomic sequence. We screened the affected chromosome 7 from the KE family with 120 of these STSs (average spacing <100 kb), but we did not detect any evidence of a microdeletion. Novel polymorphic markers were generated from the sequence and were used to further localize critical recombination breakpoints in the KE family. This allowed refinement of the SPCH1 interval to a region between new markers 013A and 330B, containing approximately 6.1 Mb of completed sequence. In addition, we have studied two unrelated patients with a similar speech and language disorder, who have de novo translocations involving 7q31. Fluorescence in situ hybridization analyses with BACs/PACs from the sequence map localized the t(5;7)(q22;q31.2) breakpoint in the first patient (CS) to a single clone within the newly refined SPCH1 interval. This clone contains the CAGH44 gene, which encodes a brain-expressed protein containing a large polyglutamine stretch. However, we found that the t(2;7)(p23;q31.3) breakpoint in the second patient (BRD) resides within a BAC clone mapping >3.7 Mb distal to this, outside the current SPCH1 critical interval. Finally, we investigated the CAGH44 gene in affected individuals of the KE family, but we found no mutations in the currently known coding sequence. These studies represent further steps toward the isolation of the first gene to be implicated in the development of speech and language.