Metaplasticity

The emergence of the human mind is a topic that has been of considerable interest to the disciplines of archaeology, cognitive archaeology and neuroscience in recent years. Most research in this regard has tended to focus on what material culture associated with early Homo sapiens might reflect in terms of the timing and nature of early cognitive capacities and ‘behavioural modernity’. In recent years, however, both the concept of ‘behavioural modernity’ and its passive treatment of material culture have become highly criticised. Yet, until now, there has remained some confusion as to where to turn in its absence. Recently, Lambros Malafouris outlined the theoretical frameworks of Material Engagement Theory and Metaplasticity as a means to understand the active role of material culture in the constitution of the human mind. However, despite Malafouris' application of these theoretical frameworks to a series of case studies previously associated with human cognitive ‘modernity’ (including tool manufacture, early body ornamentation, and ritual art), the Late Pleistocene archaeological community has done little to engage with this work. In this paper I outline and then apply MET and Metaplasticity to two further case studies often considered pertinent to the development of human cognition in the Late Pleistocene – namely, long-distance resource sourcing and/or exchange and the development of composite technologies. In doing so, I hope to demonstrate that there is somewhere to turn in the wake of the statement ‘we have never been behaviourally modern’.

In The Future of Hegel, Catherine Malabou connects plasticity to Absolute Knowing, which in her view is the knowledge of the necessity of contingency, and that the futility of trying to decide their which one of the two – necessity or contingency – has ontological priority. It thus marks ‘the openness to the event’, the eventual dissolution of any individual ‘I’ of experience. Absolute Knowing is the knowing that the composite perspectives of the dialectics cannot be disentangled, that ‘each determinate moment brings the other into view through a new angle’ (Malabou 2005, p. 166), and consequently that the individual perspective is always already bound up with other perspectives. She later opposes the use of ‘plasticity’ within neuroscience, arguing that it neglects of the moulding capacities of destruction and displays a bias towards endless flexibility. Malabou argues that in the brain is not a control centre. Its constant interaction with the environment makes any categorical division between the neuronal and the social impossible. In this paper, I will try to bring these encounters together, asking: does the concept of Absolute Knowing offer a way of grasping Malabou’s delocalized view of agency? Is she proposing a distributed or ecological sense of agency, in line with what Lambros Malafouris calls metaplasticity?
I extend this to the concept of ‘unity’ in Malabou’s reading of Hegel, leading me to the chain metaphor and the Gaia hypothesis. In relation to the latter, the terms 'sympoiesis' and 'holobiont' are introduced. They both undermine the premise of selfishness, i.e. the individual competitors acting to further their own gains, as a ‘selfish gene’ cannot be selfish if it does not have permanent boundaries – if it is constitutively entangled with other processes. While Malabou approaches these questions through the ‘mutual aid’ of Kropotkin, I am informed by Donna Haraway and Scott Gilbert (among others), who emphasize the symbiotic interrelations between organisms and ecosystems and argue that cooperation is an evolutionary factor on par with competition.

Computational models of metaplasticity have usually focused on the modeling of single synapses (Shouval et al., 2002). In this paper we study the effect of metaplasticity on network behavior. Our guiding assumption is that the primary purpose of metaplasticity is to regulate synaptic plasticity, by increasing it when input is low and decreasing it when input is high. For our experiments we adopt a model of metaplasticity that demonstrably has this effect for a single synapse; our primary interest is in how metaplasticity thus defined affects network-level phenomena. We focus on a network-level phenomenon called polychronicity, that has a potential role in representation and memory. A network with polychronicity has the ability to produce non-synchronous but precisely timed sequences of neural firing events that can arise from strongly connected groups of neurons called polychronous neural groups (Izhikevich et al., 2004). Polychronous groups (PNGs) develop readily when spiking networks are exposed to repeated spatio-temporal stimuli under the influence of spike-timing-dependent plasticity (STDP), but are sensitive to changes in synaptic weight distribution. We use a technique we have recently developed called Response Fingerprinting to show that PNGs formed in the presence of metaplasticity are significantly larger than those with no metaplasticity. A potential mechanism for this enhancement is proposed that links an inherent property of integrator type neurons called spike latency to an increase in the tolerance of PNG neurons to jitter in their inputs.

receptor-2 (HER2), which is suggested to be a reflection of absence of extensive glandular component. This cancer is considered as a subgroup of basal like breast cancers when classified by gene expression and carry a poor prognosis due to lack of response to hormonal therapy. MBC with chondroid differentiation is the rarest among all histologic 3 subtypes of breast cancer. It has worse prognosis compareed to infiltrating ductal carcinoma, even when adjusted for stage, with a 3-year overall survival rate of 48-71% and 3-year disease-free survival rate 4 of 15-60%. We report a case of metaplastic carcinoma with chondroid differentiation. CASE PRESENTATION A 56-year-old woman presented with a lump in right breast in upper outer quadrant. There was no history suggestive of nipple discharge. Family history was non-contributory. On examination, a hard non-tender mass measuring approximately 4 x 5 cm was noted in upper outer quadrant of right breast extending into axillary tail. Mass was not fixed to overlying and underlying structures. There were no obvious skin changes. A lymph node was

We review the plastic changes of the prefrontal cortex of the rat in response to a wide range of experiences including sensory and motor experience, gonadal hormones, psychoactive drugs, learning tasks, stress, social experience, metaplastic experiences, and brain injury. Our focus is on synaptic changes (dendritic morphology and spine density) in pyramidal neurons and the relationship to behavioral changes. The most general conclusion we can reach is that the prefrontal cortex is extremely plastic and that the medial and orbital prefrontal regions frequently respond very differently to the same experience in the same brain and the rules that govern prefrontal plasticity appear to differ for those of other cortical regions.

Endocannabinoids are known as retrograde messengers, being released from the postsynaptic neuron and acting on specific presynaptic G-protein-coupled cannabinoid (CB) receptors to decrease neurotransmitter release. Also, at physiologically relevant concentrations cannabinoids can directly modulate the function of voltage-gated and receptor-operated ion channels. Using patch-clamp recording we analyzed the consequences of the direct action of an endocannabinoid, 2-arachidonoylglycerol (2-AG), on the functional properties of glycine receptor channels (GlyRs) and ionic currents in glycinergic synapses. At physiologically relevant concentrations (0.1-1 μM), 2-AG directly affected the functions of recombinant homomeric α1H GlyR: it inhibited peak amplitude and dramatically enhanced desensitization. The action of 2-AG on GlyR-mediated currents developed rapidly, within ∼300 ms. Addition of 1 μM 2-AG strongly facilitated the depression of glycine-induced currents during repetitive (4-10 Hz...