Visual cortical neurophysiology
Visual cortical neurophysiology

Understanding the neuronal substrates of visual cognition is one of the ultimate goals of systems neuroscience. In our lab, we investigate how visual information is processed and reformatted across the cortical visual hierarchy, by performing multi-electrode neuronal recordings from multiple visual areas of the rat brain. Our work has focused on anatomical progression of extrastriate areas that, in the rat brain, run laterally to V1 (i.e., areas LM, LI, and LL), revealing a functional homology of this pathway with the primate ventral visual stream. Specifically, we found, along this progression:

  • a sharp reduction of the amount of low-level information encoded by neuronal firing, and a concomitant increase in the ability of neuronal representations to support object recognition (Tafazoli et al., 2017)
  • an increase of the nonlinearity of neuronal responses, along with a reduction of orientation tuning and an increase of the tendency of neurons to be tuned for multiple orientations (Matteucci et al., 2019)
  • an increase in the temporal stability of neuronal representations of visual objects, both in terms of stimulus-evoked activity responses and intrinsic activity¬†(Piasini et al., 2021)

We have also investigated whether rat visual cortex supports high-order processing of motion information, finding evidence of nonlinear integration of motion signals by a small population of primate-like pattern cells in V1 and LM (Matteucci et al, 2023).

In addition, we have started to explore the instructive role of visual experience during early postnatal life by rearing newborn rats in visually controlled environments. This approach has revealed that experiencing a temporal continuous visual world is necessary for the proper development of complex cells in V1 - the class of visual neurons that first show the property of transformation invariance in the visual system (Matteucci and Zoccolan, 2020).

Finally, earlier studies of the PI and his collaborators have investigated the properties of visual object representations in monkey inferotemporal cortex (IT), including:

  • the encoding of multiple visual objects by IT neurons (Zoccolan et al., 2005; Li et al., 2009)
  • the relationship between shape selectivity and transformation tolerance in IT (Zoccolan et al., 2007)
  • the encoding of shape and semantic information in IT (Baldassi et al., 2013)

See below for a complete list of our neurophysiological studies.

Selected articles
Truly pattern: Nonlinear integration of motion signals is required to account for the responses of pattern cells in rat visual cortex
Matteucci G, Bellacosa Marotti R, Zattera B, Zoccolan D (2023)
Science Adv.: 9 (45), eadh4690
Temporal stability of stimulus representation increases along rodent visual cortical hierarchies
Piasini E*, Soltuzu L*, Muratore P, Caramellino R, Vinken K, Op De Beeck H, Balasubramanian V & Zoccolan D (2021)
Nature Comm.: 12, 4448
A template-matching algorithm for laminar identification of cortical recording sites from evoked response potentials.
Matteucci G*, Riggi M* & Zoccolan D (2020)
J. Neurophys.: 124, 102-114
Unsupervised experience with temporal continuity of the visual environment is causally involved in the development of V1 complex cells.
Matteucci G & Zoccolan D (2020)
Science Adv.: 6(22), eaba3742
A passive, camera-based head-tracking system for real-time, three-dimensional estimation of head position and orientation in rodents.
Vanzella W*, Grion N*, Bertolini D*, Perissinotto A, Gigante M & Zoccolan D (2019)
J. Neurophys. : 122, 2220-2242
Nonlinear processing of shape information in rat lateral extrastriate cortex.
Matteucci G, Bellacosa Marotti R, Riggi M, Rosselli FB & Zoccolan D (2019)
J. Neurosci. : 39, 1649-1670
Characterization of visual object representations in rat primary visual cortex.
Vascon S*, Parin Y*, Annavini E*, D’Andola M, Zoccolan D & Pelillo M (2019)
ECCV 2018, Lect. Notes Comp. Science: 11131, 577-586
Supralinear and supramodal integration of visual and tactile signals in rats: psychophysics and neuronal mechanisms.
Nikbakht N, Tafreshiha A, Zoccolan D & Diamond ME (2018)
Neuron : 97, 626-639
Emergence of transformation-tolerant representations of visual objects in rat lateral extrastriate cortex.
Tafazoli S*, Safaai H*, De Franceschi G, Rosselli FB, Vanzella W, Riggi M, Buffolo F, Panzeri S & Zoccolan D (2017)
eLife: 6:e22794
Shape similarity, better than semantic membership, accounts for the structure of visual object representations in a population of monkey inferotemporal neurons.
Baldassi C*, Alemi-Neissi A*, Pagan M*, DiCarlo JJ, Zecchina R & Zoccolan D (2013)
PLoS Comput. Biol.: 9(8): e1003167
What response properties do individual neurons need to underlie object recognition in clutter?
Li N, Cox DD, Zoccolan D & DiCarlo JJ (2009)
J. Neurophys. : 102, 360-376
Trade-off between object selectivity and tolerance in monkey inferotemporal cortex.
Zoccolan D, Kouh M, Poggio T & DiCarlo JJ (2007)
J. Neurosci. : 27, 12292-12307
Multiple object response normalization in monkey inferotemporal cortex.
Zoccolan D*, Cox DD* & DiCarlo JJ (2005)
J. Neurosci. : 25, 8150-64