Papers for the month of May 2013

"Initiation, labile, and stabilization phases of experience-dependent plasticity at neocortical synapses"
Journal of Neuroscience, 33(19):8483-93.

Mouse over here for a brief summary or click to open article in a new tab.Here we identify three discrete stages in synaptic strengthening induced by sensory activity in barrel cortex of rodents. Glutamatergic synapses initially get very large, and then enter into a short-lived "labile" phase, where continuing sensory input reduces synaptic strength. This phase is followed by the stabilization of synaptic strength at potentiated inputs.

"Selective Dissociation Between Core and Extended Regions of the Face Processing Network in Congenital Prosopagnosia"
Cerebral Cortex, doi:10.1093/cercor/bht007:/bht007

Mouse over here for a brief summary or click to open article in a new tab.There is growing consensus that accurate and efficient face recognition is mediated by a neural circuit composed of a posterior “core” and an anterior “extended” set of regions. In this paper, we characterize the distributed face network in human individuals with congenital prosopagnosia (CP)—a lifelong impairment in face processing—relative to that of matched controls. Using functional MRI, we show that the posterior core regions are intact in CP but that these are selectively dissociated from the anterior temporal lobe while amygdala activation remains normal. These findings elucidate selective disruptions in neural circuitry in CP and offer an explanation for the known differential difficulty in identity versus emotional expression recognition in many individuals with CP.

"Analysis of synchronization in a slowly changing environment: How slow coupling becomes fast weak coupling"
Physical Review Letters, 110:204101

Mouse over here for a brief summary or click to open article in a new tab.Many physical systems strongly interact with their environments: the environment affects their behavior, while their behavior in turn alters the environment. If multiple animals, cells, or other units co-exist in the same environment, then they may influence each other indirectly through their effects on their common environment. This paper presents a new, general mathematical approach that we developed for analyzing how these indirect interactions can promote or prevent coordination of the units involved. The method applies to physical systems of components with two ingredients: (1) on their own, the components oscillate in time (that is, some aspect of the system rises and falls, repeatedly, over time), and (2) the components interact through an external medium or environment that changes gradually. Examples of such systems include neurons with oscillations in their membrane potentials (what neurons use to send signals to other neurons) that share an external ion pool (since neuronal oscillations require these ions), particularly in settings with high neuronal activity levels such as epilepsy; bacteria with internal oscillations in gene expression that live in a common medium; or predator-prey pairs living in a common ecosystem (e.g., stoats and songbirds, owls and insects in the woods).

"High-performance neuroprosthetic control by an individual with tetraplegia."
Lancet, 6736:61816

Mouse over here for a brief summary or click to open article in a new tab.Control signals extracted from neural activity recorded with microelectrode arrays implanted in motor cortex were used by a quadriplegic woman to operate a high-performance prosthetic arm to carry out tasks of daily living.

"Consistency under Sampling of Exponential Random Graph Models"
Annals of Statistics, 41:508

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"Explicating the face perception network with white-matter connectivity"
PLoS ONE, 8:4

Mouse over here for a brief summary or click to open article in a new tab.We used fMRI in combination with fiber tractography on high angular resolution diffusion weighted imaging data to study structural connectivity across three nodes of the "core" face network, as well as one more anterior region. Most interestingly, we found no evidence for connectivity between STS and mid-fusiform gyrus, or between STS and the other face-selective brain regions.

"The Case for Zombie Agency"
Mind, 10.1093/mind/fzt030:1-14

Mouse over here for a brief summary or click to open article in a new tab.The philosophical metaphor of a zombie is of a creature lacking consciousness. Are we zombie agents, creatures whose actions are directly programmed by unconscious states? A natural view denies this: actions are guided by conscious experience of the world. Yet Goodale and Milner controversially defend the affirmative answer in terms of the unconscious dorsal visual stream. This essay gives a different argument that we are, to some extent, zombie agents.