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New Research published in Scientific Reports

Congratulations to Paola who published a new paper on Scientific Reports!

Binda, P., Strasser, T., Stingl, K., Richter, P., Peters, T., Wilhelm, H., et al. (2017). Pupil response components: attention-light interaction in patients with Parinaud's syndrome, Sci Rep, 1 (7), 10283. PDF

Covertly shifting attention to a brighter or darker image (without moving one's eyes) is sufficient to evoke pupillary constriction or dilation, respectively. One possibility is that this attentional modulation involves the pupillary light response pathway, which pivots around the olivary pretectal nucleus. We investigate this possibility by studying patients with Parinaud's syndrome, where the normal pupillary light response is strongly impaired due to lesions in the pretectal area. Four patients and nine control participants covertly attended (while maintaining fixation at the center of a monitor screen) to one of two disks located in the left and right periphery: one brighter, the other darker than the background. Patients and control subjects behaved alike, showing smaller pupils when attending to the brighter stimulus (despite no eye movements); consistent results were obtained with a dynamic version of the stimulus. We interpret this as proof of principle that attention to bright or dark stimuli can dynamically modulate pupil size in patients with Parinaud's syndrome, suggesting that attention acts independently of the pretectal circuit for the pupillary light response and indicating that several components of the pupillary response can be isolated - including one related to the focus of covert attention.

New Research published on Current Biology!

Congratulation to Koulla, Jan, Dave and Concetta who just published on Current Biology!

Mikellidou, K., Kurzawski, J. W., Frijia, F., Montanaro, D., Greco, V., Burr, D. C., and Morrone M.C. (2017). Area Prostriata in the Human Brain, Current Biology, (27), PDF

Area prostriata is a cortical area at the fundus of the calcarine sulcus, described anatomically in humans [ 1–5 ] and other primates [ 6–9 ]. It is lightly myelinated and lacks the clearly defined six-layer structure evident throughout the cerebral cortex, with a thinner layer 4 and thicker layer 2 [ 10 ], characteristic of limbic cortex [ 11 ]. In the marmoset and rhesus monkey, area prostriata has cortical connections with MT+ [ 12 ], the cingulate motor cortex [ 8 ], the auditory cortex [ 13 ], the orbitofrontal cortex, and the frontal polar cortices [ 14 ]. Here we use functional magnetic resonance together with a wide-field projection system to study its functional properties in humans. With population receptive field mapping [ 15 ], we show that area prostriata has a complete representation of the visual field, clearly distinct from the adjacent area V1. As in the marmoset, the caudal-dorsal border of human prostriata—abutting V1—represents the far peripheral visual field, with eccentricities decreasing toward its rostral boundary. Area prostriata responds strongly to very fast motion, greater than 500°/s. The functional properties of area prostriata suggest that it may serve to alert the brain quickly to fast visual events, particularly in the peripheral visual field.

New Commentary in Behavioral and Brain Science

Congratulations to
David, whose latest paper has just been published in Behavioral and Brain Science!

Burr, D. C. (2017). Evidence for a number sense, Behavioral and Brain Sciences, (40), 18-19. PDF

Numerosity is inherently confounded by related stimulus attributes such as density and area, and many studies have reported interactions of various strengths between area, density, and numerosity. However, direct measurements of sensitivity within the area-density-numerosity space show that numerosity emerges as the most spontaneous and sensitive dimension, strongly supporting the existence of a dedicated number sense.

New Commentary in Behavioral and Brain Science

Congratulations to
Elisa, whose latest paper has just been published in Behavioral and Brain Science!

de Hevia, M. D., Castaldi, E., Streri, A., Eger, E. & Izard, V. (2017). Perceiving numerosity from birth, Behavioral and Brain Sciences, (40), 21-22. PDF

Leibovich et al. opened up an important discussion on the nature and origins of numerosity perception. The authors rightly point out that non-numerical features of stimuli influence this ability. Despite these biases, there is evidence that from birth, humans perceive and represent numerosities, and not just non-numerical quantitative features such as item size, density, and convex hull.

New Spotlight published on Trends in Neuroscience!

Congratulation to Paola who just published a new paper on Trends in Neuroscience!

Binda, P. & Gamlin, P. D. (2017). Renewed Attention on the Pupil Light Reflex, Trends Neurosci, PDF

In a recent study, Ebitz and Moore described how subthreshold electrical microstimulation of the macaque frontal eye fields (FEF) modulates the pupillary light reflex. This elegant study suggests that the influence of the FEF and prefrontal cortex on attentional modulation of cortical visual processing extends to the subcortical circuit that mediates a very basic reflex, the pupillary light reflex.

New Research published on Journal of Neurophysiology!

Congratulation to Concetta who just published a new paper on Journal of Neurophysiology!

Sani, I., Santandrea, E., Morrone, M. C. & Chelazzi, L. (2017). Temporally Evolving Gain Mechanisms of Attention in Macaque Area V4, J Neurophysiol, jn 00522 02016. PDF

Cognitive attention and perceptual saliency jointly govern our interaction with the environment. Yet, we still lack a universally accepted account of the interplay between attention and luminance contrast - a fundamental dimension of saliency. We measured the attentional modulation of V4 neurons' Contrast Response Functions (CRFs) in awake, behaving macaque monkeys and applied a new approach which emphasizes the temporal dynamics of cell responses. We found that attention modulates CRFs via different gain mechanisms during subsequent epochs of visually driven activity: an early contrast-gain - strongly dependent on pre-stimulus activity changes (baseline shift), a time-limited stimulus-dependent multiplicative modulation, reaching its maximal expression around 150 ms after stimulus onset, and a late resurgence of contrast-gain modulation. Attention produced comparable time-dependent attentional gain changes on cells heterogeneously coding contrast, supporting the notion that the same circuits mediate attention mechanisms in V4 regardless of the form of contrast selectivity expressed by the given neuron. Surprisingly, attention was also sometimes capable of inducing radical transformations in the shape of CRFs. These findings offer important insights into the mechanisms that underlie contrast coding and attention in primate visual cortex and a new perspective on their interplay, one in which time becomes a fundamental factor.

New Research published on Journal of Neuropsychology!

Congratulation to Marco who just published a new paper on Journal of Neuropsychology!

Chilosi, A. M., Bulgheroni, S., Turi, M., Cristofani, P., Biagi, L., Erbetta, A., et al. (2017). Hemispheric language organization after congenital left brain lesions: A comparison between functional transcranial Doppler and functional MRI, J Neuropsychol, PDF

This study investigated whether functional transcranial Doppler ultrasound (fTCD) is a suitable tool for studying hemispheric lateralization of language in patients with pre-perinatal left hemisphere (LH) lesions and right hemiparesis. Eighteen left-hemisphere-damaged children and young adults and 18 healthy controls were assessed by fTCD and fMRI to evaluate hemispheric activation during two language tasks: a fTCD animation description task and a fMRI covert rhyme generation task. Lateralization indices (LIs), measured by the two methods, differed significantly between the two groups, for a clear LH dominance in healthy participants and a prevalent activation of right hemisphere in more than 80% of brain-damaged patients. Distribution of participants in terms of left, right, and bilateral lateralization was highly concordant between fTCD and fMRI values. Moreover, right hemisphere language dominance in patients with left hemispheric lesions was significantly associated with severity of cortical and subcortical damage in LH. This study suggests that fTCD is an easily applicable tool that might be a valid alternative to fMRI for large-scale studies of patients with congenital brain lesions.

New Research published on Current Biology!

Congratulation to David who just published on Current Biology!

Kagan, I. & Burr, D. C. (2017). Active Vision: Dynamic Reformatting of Visual Information by the Saccade-Drift Cycle, Curr Biol, 9 (27), R341-R344. PDF

Visual processing depends on rapid parsing of global features followed by analysis of fine detail. A new study suggests that this transformation is enabled by a cycle of saccades and fixational drifts, which reformat visual input to match the spatiotemporal sensitivity of fast and slow neuronal pathways.

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