The barrel cortex—integrating molecular, cellular and systems physiology

A challenge for neurobiology is to integrate information across many levels of research, ranging from behaviour and neuronal networks to cells and molecules. The rodent whisker signalling pathway to the primary somatosensory neocortex with its remarkable somatotopic barrel map is emerging as a key system for such integrative studie

Alien Registration- Petersen, Carl H. (Portland, Cumberland County)

https://digitalmaine.com/alien_docs/31194/thumbnail.jp

From Perception to Action: A Spatiotemporal Cortical Map

In this issue of Neuron, Guo et al. (2014) optogenetically probe contributions of different cortical regions to tactile sensory perception, finding that somatosensory cortex is necessary for acquisition of sensory information and frontal cortex is necessary for planning motor output

Effect of Indian clubbell exercises on cricket fast bowlers’ shoulder kinematics

Background: The glenohumeral joint’s rotational range of motion (ROM) and muscle strength are essential to execute the cricket bowling action. Performing shoulder rotation exercises may increase the rotator cuff muscle strength and rotational ROM.  Objectives: The aim of this study was to test the effect of a six-week exercise programme on shoulder rotational ROM and muscle strength. Methods: Twenty-one healthy male cricket fast bowlers were recruited, ranked and pair-matched on initial shoulder rotator muscle strength and assigned to either a shoulder exercise (SE) group or cricket training (CT) only group. The SE group incorporated Indian clubbell exercises in addition to their cricket training. Results: Bowlers in both groups displayed a large increase on the dominant shoulder’s internal rotation (IR) ROM, but only the SE group’s bowlers displayed ROM improvements (p<0.001) bilaterally for both internal and external rotation. The CT group’s fast bowler’s non-dominant shoulder IR ROM significantly decreased (p=0.02) during the six weeks. Between groups, only the SE group’s bowler’s internal rotator muscle strength improved (p<0.001) bilaterally. The observed kinematic changes were statistically significantly greater at a 5% level for the SE group’s bowlers (bilateral internal rotators muscle strength, non-dominant shoulder IR ROM and horizontal adduction ROM). Conclusion: Maintenance of the shoulder’s rotational ROM and muscle strength is vital for a fast bowler. Cricket bowlers who perform regular clubbell exercises might increase their shoulder’s ROM and internal rotator cuffs’ muscle strength, which may aid in stabilising their glenohumeral joint while bowling.

Layer- and Column-Specific Knockout of NMDA Receptors in Pyramidal Neurons of the Mouse Barrel Cortex

Viral vectors injected into the mouse brain offer the possibility for localized genetic modifications in a highly controlled manner. Lentivector injection into mouse neocortex transduces cells within a diameter of approximately 200μm, which closely matches the lateral scale of a column in barrel cortex. The depth and volume of the injection determines which cortical layer is transduced. Furthermore, transduced gene expression from the lentivector can be limited to predominantly pyramidal neurons by using a 1.3kb fragment of the αCaMKII promoter. This technique therefore allows genetic manipulation of a specific cell type in defined columns and layers of the neocortex. By expressing Cre recombinase from such a lentivector in gene-targeted mice carrying a floxed gene, highly specific genetic lesions can be induced. Here, we demonstrate the utility of this approach by specifically knocking out NMDA receptors (NMDARs) in pyramidal neurons in the somatosensory barrel cortex of gene-targeted mice carrying floxed NMDAR 1 genes. Neurons transduced with lentivector encoding GFP and Cre recombinase exhibit not only reductions in NMDAR 1 mRNA levels, but reduced NMDAR-dependent currents and pairing-induced synaptic potentiation. This technique for knockout of NMDARs in a cell type, column- and layer-specific manner in the mouse somatosensory cortex may help further our understanding of the functional roles of NMDARs in vivo during sensory perception and learning