Explore the vast range of titles available.

Signalling brain size The mechanisms controlling brain size are central to developmental genetics, neurobiology and mammalian evolution. A new study shows that a class of signalling factors present in the developing brain, the ephrins, induces the death of the progenitor or stem cells that generate all neurons, and thereby control the final size of the cerebral cortex. When this ‘death signal’ is increased, brain size decreases, resulting in microcephaly. When it decreases, cortical size increases, leading to exencephalic brain overgrowth. This has implications for brain diseases, regeneration, and cancer. Mechanisms controlling brain size include the regulation of neural progenitor cell proliferation, differentiation, survival and migration 1 , 2 . Here we show that ephrin-A/EphA receptor signalling plays a key role in controlling the size of the mouse cerebral cortex by regulating cortical progenitor cell apoptosis. In vivo gain of EphA receptor function, achieved through ectopic expression of ephrin-A5 in early cortical progenitors expressing EphA7, caused a transient wave of neural progenitor cell apoptosis, resulting in premature depletion of progenitors and a subsequent dramatic decrease in cortical size. In vitro treatment with soluble ephrin-A ligands similarly induced the rapid death of cultured dissociated cortical progenitors in a caspase-3-dependent manner, thereby confirming a direct effect of ephrin/Eph signalling on apoptotic cascades. Conversely, in vivo loss of EphA function, achieved through EphA7 gene disruption, caused a reduction in apoptosis occurring normally in forebrain neural progenitors, resulting in an increase in cortical size and, in extreme cases, exencephalic forebrain overgrowth. Together, these results identify ephrin/Eph signalling as a physiological trigger for apoptosis that can alter brain size and shape by regulating the number of neural progenitors.

Many exotic animal species were introduced to Northern Europe during the Roman period, including fallow deer (Dama dama). To date, however, finds of fallow deer bones at archaeological sites in this region have been sporadic and disarticulated, leaving uncertainty over their origins. This article presents the first known articulated fallow deer skeleton from Roman North-western Europe. Osteological, ancient DNA, radiocarbon dating and stable isotope analyses confirm that the species was established in this region by the Roman period, probably originating from translocated, rather than native, Mediterranean populations. Clarifying the origins of fallow deer in North-western Europe is critical for understanding the dynamics of species exchange around the Roman Empire.

Many exotic animal species were introduced to Northern Europe during the Roman period, including fallow deer (Dama dama). To date, however, finds of fallow deer bones at archaeological sites in this region have been sporadic and disarticulated, leaving uncertainty over their origins. This article presents the first known articulated fallow deer skeleton from Roman North-western Europe. Osteological, ancient DNA, radiocarbon dating and stable isotope analyses confirm that the species was established in this region by the Roman period, probably originating from translocated, rather than native, Mediterranean populations. Clarifying the origins of fallow deer in Northwestern Europe is critical for understanding the dynamics of species exchange around the Roman Empire.

Posterior cortical atrophy is an uncommon type of dementia often caused by Alzheimer’s disease and characterised by progressive loss of visuospatial and perceptual abilities. Although there is no curative treatment, patients may benefit from a range of symptom-based techniques and strategies to address visuospatial deficits and apraxia, and to reduce disability. Specific techniques based on visual and tactile cues, adapted and assistive equipment, environmental modifications and skill training may help people with posterior cortical atrophy continue to carry on activities that are important to them. We share vignettes from patients treated in our clinics to illustrate the practical delivery and potential impact of these therapies.

People with semantic variant primary progressive aphasia (svPPA) present with a characteristic progressive breakdown of semantic knowledge. There are currently no pharmacological interventions to cure or slow svPPA, but promising behavioural approaches are increasingly reported. This article offers an overview of the last two decades of research into interventions to support language in people with svPPA including recommendations for clinical practice and future research based on the best available evidence. We offer a lay summary in English, Spanish and French for education and dissemination purposes. This paper discusses the implications of right- versus left-predominant atrophy in svPPA, which naming therapies offer the best outcomes and how to capitalise on preserved long-term memory systems. Current knowledge regarding the maintenance and generalisation of language therapy gains is described in detail along with the development of compensatory approaches and educational and support group programmes. It is concluded that there is evidence to support an integrative framework of treatment and care as best practice for svPPA. Such an approach should combine rehabilitation interventions addressing the language impairment, compensatory approaches to support activities of daily living and provision of education and support within the context of dementia.