The skull of Monolophosaurus jiangi (Dinosauria:Theropoda) and its implications for early theropod phylogeny and evolution

The Middle Jurassic was a critical time in the evolution of theropod dinosaurs, highlighted by the origination and initial radiation of the large-bodied and morphologically diverse Tetanurae. Middle Jurassic tetanurans are rare, but have been described from Europe, South America and China. In particular, China has yielded a number of potential basal tetanurans, but these have received little detailed treatment in the literature. Chief among these is Monolophosaurus jiangi, known from a single skeleton that includes a nearly complete and well-preserved skull characterized by a bizarre cranial crest. Here, we redescribe the skull of Monolophosaurus, which is one of the most complete basal tetanuran skulls known and the only quality source of cranial data for Middle Jurassic Chinese theropods. The cranial crest is atomized into a number of autapomorphic features and several characters confirm the tetanuran affinities of Monolophosaurus. However, several features suggest a basal position within Tetanurae, which contrasts with most published cladistic analyses, which place Monolophosaurus within the more derived Allosauroidea. Cranial characters previously used to diagnose Allosauroidea are reviewed and most are found to have a much wider distribution among Theropoda, eroding an allosauroid position for Monolophosaurus and questioning allosauroid monophyly. The use of phylogenetic characters relating to theropod cranial crests is discussed and a protocol for future use is given. The systematic position of Guanlong wucaii is reviewed, and a basal tyrannosauroid affinity is upheld contrary to one suggestion of a close relationship between this taxon and Monolophosaurus. © 2010 The Linnean Society of London

The neural basis of multisensory spatial and feature-based attention in vision and somatosensation

Attention refers to the cognitive processes that prioritise a subset of available sensory information for enhanced processing, and which can be directed towards spatial locations, object features, time, or other aspects of the environment. While the majority of research has focused on studying attention within sensory modalities, a growing body of evidence has demonstrated that attention interact with multisensory processes. Several neuroimaging studies have shown that higher cortical regions activated during attention to multiple sensory modalities overlap significantly with the dorsal and ventral frontoparietal regions activated during visual attention tasks. This evidence has led some researchers to propose the existence of supramodal frontoparietal system that controls the deployment of attention across various sensory modalities. Although influential, this hypothesis has been challenged by other studies that discovered evidence for modality-specific regions in the parietal cortex. In this thesis, I investigated the generality and specificity of the frontoparietal network associated with multisensory spatial and feature-based attention, in vision and touch, by applying multivoxel pattern analysis (MVPA) to fMRI data. Recent studies have successfully demonstrated that MVPA methods could be used to discriminate various experimental conditions from weak distributed patterns of activity within overlapping cortical regions found by univariate fMRI analysis. Here, I applied similar logic to examine overlapping frontoparietal regions activated during multisensory attention. Contrary to the supramodal hypothesis, the results supported the existence of modality-specific systems in the posterior parietal cortex during both attention to spatial locations and stimulus features. Additional evidence for modality-specific processes was also indicated in the patterns of top-down modulatory activity in visual cortex. Overall, the current findings supported the view that both modality-specific and potentially supramodal frontoparietal regions work in concert to selectively bias activity in sensory cortical regions during various states of attention