Elementary units of cortical activity? The rise and fall of the cortical column

The roots of the concept of cortical columns stretch far back into the history of neuroscience. The impulse to compartmentalise the cortex into functional units can be seen at work in the phrenology of the beginning of the nineteenth century. At the beginning of the next century Korbinian Brodmann and several others published treatises on cortical architectonics. Later, in the middle of that century, Lorente de No writes of chains of ‘reverberatory’ neurons orthogonal to the pial surface of the cortex and called them ‘elementary units of cortical activity’. This is the first hint that a columnar organisation might exist. With the advent of microelectrode recording first Vernon Mountcastle (1957) and then David Hubel and Torsten Wiesel provided evidence consistent with the idea that columns might constitute units of physiological activity. This idea was backed up in the 1970s by clever histochemical techniques and culminated in Hubel and Wiesel’s well-known ‘ice-cube’ model of the cortex and Szentogathai’s brilliant iconography. The cortical column can thus be seen as the terminus ad quem of several great lines of neuroscientific research: currents originating in phrenology and passing through cytoarchitectonics; currents originating in neurocytology and passing through Lorente de No. Famously, Huxley noted the tragedy of a beautiful hypothesis destroyed by an ugly fact. Famously, too, human visual perception is orientated toward seeing edges and demarcations when, perhaps, they are not there. Recently the concept of cortical columns has come in for the same radical criticism that undermined the architectonics of the early part of the twentieth century. Does history repeat itself? This paper reviews this history and asks the question.

Volunteering for success:mentoring as a form of student volunteering

Previous studies into student volunteering have shown how formally organized volunteering activities have social, economic and practical benefits for student volunteers and the recipients of their volunteerism (Egerton, 2002; Vernon & Foster, 2002); moreover student volunteering provides the means by which undergraduates are able to acquire and hone transferable skills sought by employers following graduation (Eldridge & Wilson, 2003; Norris et al, 2006). Within the UK Higher Education Sector, a popular mechanism for accessing volunteering is through formally organized student mentoring programmes whereby more ‘senior’ students volunteer to mentor less experienced undergraduates through a particular phase of their academic careers, including the transition from school or college to university. The value of student mentoring as a pedagogical tool within Higher Education is reflected in the literature (see for example, Bargh & Schul, 1980, Hartman,1990, Woodd, 1997). However, from a volunteering perspective, one of the key issues relates to the generally accepted conceptualisation of volunteering as a formally organized activity, that is un-coerced and for which there is no payment (Davis Smith, 1992, 1998; Sheard, 1995). Although the majority of student mentoring programs discussed in the paper are unpaid and voluntary in nature, in a small number of institutions some of the mentoring programs offered to students provide a minimum wage for mentors. From an ethical perspective, such payments may cause difficulties when considering potential mentors’ motivations and reasons for participating in the program. Additionally, institutions usually only have one or two paid mentoring programs running alongside several voluntary programmes – sometimes resulting in an over-subscription for places as paid mentors to the detriment of unpaid programs. Furthermore, from an institutional perspective, student mentoring presents a set of particular ethical problems reflecting issues around ‘matching’ mentors and mentees in terms of gender, race, ethnicity and religion. This is found to be the case in some ‘targeted’ mentoring programs whereby a particular demographic group of students are offered access to mentoring in an attempt to improve their chances of academic success. This paper provides a comparative analysis of the experiences and perceptions of mentors and mentees participating in a wide-range of different mentoring programs. It also analyzes the institutional challenges and benefits associated with managing large scale student volunteering programs. In doing so the paper adds to third sector literature by critiquing the distinctive issues surrounding student volunteering and by discussing, in-depth, the management of large groups of student volunteers. From a public policy perspective, the economic, educational, vocational and social outcomes of student volunteering make this an important subject meriting investigation. Little is known about the mentoring experiences of student volunteers with regards to the ‘added value’ of participating in campus-based volunteering activities. Furthermore, in light of the current economic downturn, by drawing attention to the contribution that student volunteering plays in equipping undergraduates with transferable ‘employability’ related skills and competencies (Andrews & Higson, 2008), this paper makes an important contribution to current educational and political debates. In addition to providing the opportunity for students to acquire key transferable skills, the findings suggest that mentoring encourages students to volunteer in other areas of university and community life. The paper concludes by arguing that student mentoring provides a valuable learning experience for student volunteer mentors and for the student and pupil mentees with whom they are placed.

Volunteering for success? An Analysis of Student Perceptions of the Pedagogical and Social Outcomes of Peer Mentoring in Higher Education

Previous studies into student volunteering have shown how formally organized volunteering activities have social, economic and practical benefits for student volunteers and the recipients of their volunteerism (Egerton, 2002; Vernon & Foster, 2002); moreover student volunteering provides the means by which undergraduates are able to acquire and hone transferable skills sought by employers following graduation (Eldridge & Wilson, 2003; Norris et al, 2006). Although much is known about the benefits of student volunteering, few previous studies have focused on the pedagogical value of student mentoring from the perspectives of both student mentee and mentor. Utilising grounded theory methodology this paper provides a critical analysis of an exploratory study analysing students’ perceptions of the pedagogical and social outcomes of student mentoring. It looks at students’ perceptions of mentoring, and being mentored, in terms of the learning experience and development of knowledge and skills. In doing so the paper considers how volunteering in a mentoring capacity adds ‘value’ to students’ experiences of higher education. From a public policy perspective, the economic, educational, vocational and social outcomes of student volunteering in general, and student mentoring in particular, make this an important subject meriting investigation. In terms of employability, the role of mentoring in equipping mentors and mentees with transferable, employability competencies has not been investigated. By critiquing the mentoring experiences of undergraduates within a single institution, this paper will make an important contribution to policy debates with regards to the pedagogical and employability related outcomes of student volunteering and mentoring.

Wage inequality and productivity growth:motivating sticks and crippling carrots

Wage inequality is a particular focus of attention not only in public debates over the need for social regulation to support equity, but those over the implications of social regulation for productive performance. The present paper employs panel techniques to examine the comparative historical relationship between wage inequality and hourly labour productivity growth in the manufacturing sectors of nine advanced industrialised nations over the period 1970-1995. The results show that whilst greater inequality in the top half of the wage distribution is associated with greater productivity growth, greater inequality in the bottom half is associated with lower productivity growth. It appears that whilst wage inequality in the top half of the distribution productively motivates higher earners, wage inequality in the bottom half of the distribution is detrimental for productivity performance. The latter result is most likely attributable to the weak incentives to reorganise production where extremely low pay is feasible.

Decreased efficiency of trypsinization of cells following photodynamic therapy:evaluation of a role for tissue transglutaminase

Identifying the cellular responses to photodynamic therapy (PDT) is important if the mechanisms of cellular damage are to be fully understood. The relationship between sensitizer, fluence rate and the removal of cells by trypsinization was studied using the RIF-1 cell line. Following treatment of RIF-1 cells with pyridinium zinc (II) phthalocyanine (PPC), or polyhaematoporphyrin at 10 mW cm−2 (3 J cm−2), there was a significant number of cells that were not removed by trypsin incubation compared to controls. Decreasing the fluence rate from 10 to 2.5 mW cm−2 resulted in a two-fold increase in the number of cells attached to the substratum when PPC used as sensitizer; however, with 5,10,15,20 meso-tetra(hydroxyphenyl) chlorin (m-THPC) there was no resistance to trypsinization following treatment at either fluence rate. The results indicate that resistance of cells to trypsinization following PDT is likely to be both sensitizer and fluence rate dependent. Increased activity of the enzyme tissue-transglutaminase (tTGase) was observed following PPC-PDT, but not following m-THPC-PDT. Similar results were obtained using HT29 human colonic carcinoma and ECV304 human umbilical vein endothelial cell lines. Hamster fibrosarcoma cell (Met B) clones transfected with human tTGase also exhibited resistance to trypsinization following PPC-mediated photosensitization; however, a similar degree of resistance was observed in PDT-treated control Met B cells suggesting that tTGase activity alone was not involved in this process.