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Humans' (and other mammals') brains are devoted to a large part to visual processing.

Vision is an important if not the most important source of sensory input for humans' (and other mammals').

LGN and V4 have distinct layers for each eye.

The distinct layers for each eye in LGN and V4 only arise after the initial projections from the retina are made, but, in higher mammals, before birth.

Most neurons in the visual cortex (except v4) are binocular.

Usually, input from one eye is dominant, however.

The distribution of monocular dominance in visual cortex neurons is drastically affected by monocular stimulus deprivation during early development.

Most non-primate mammals do not have specialized photoreceptors for the medium-wavelength band. Most primates do.

Neural responses in LGN to short and medium-to-long wavelengths of light are antagonistic in rodents and cats (in certain cells).

Buzás et al. found blue-ON-type cells in the cat LGN, but no blue-OFF cells.

Blue-ON-type cells in primate and cat LGN have large receptive fields

Visual sensitivity is strongly reduced during saccades.

Visual sensitivity is strongly enhanced after saccades.

LGN is the earliest stage in the visual pathway receiving feedback (the retina does not).

Lee and Mumford link their theory to resonance and predictive coding.

The model proposed by Heinrich et al. builds upon the one by Hinoshita et al. It adds visual input and thus shows how learning of language may not only be grounded in perception of verbal utterances, but also in visual perception.

Flies' flying and walking behavior is relatively directly influenced by visual stimulation: Basic stimuli that suggest body rotation of the fly will lead to compensatory flying and walking direction.

Flies use translational optic flow to detect impending collisions.

Direct connections from the vision to the motor system lead to highly stereotyped visuomotor behavior in the fly.

The stereotyped visuomotor flying behavior in the fly is mediated by internal states and input from other sensory modalities.

Neurons at later stages in the hierarchy of visual processing extract very complex features (like faces).

Rearing barn owls in darkness results in mis-alignment of auditory and visual receptive fields in the owls' optic tectum.

Rearing barn owls in darkness results in discontinuities in the map of auditory space of the owls' optic tectum.

Retinotopic organization of a visual structure as the SC in the brain can be determined using fMRI.

Visually active neurons in FEF do not project to SC. Motion-related neurons in FEF project to SC.

The lateral geniculate nucleus (lgn) is described as some sort of waystation.

The lateral geniculate nucleus (lgn) receives visual, auditory and higher cognitive input. According to Winston, 80% of lgn input is non-visual.

Ideal observer models of cue integration were introduced in vision research but are now used in other uni-sensory tasks (auditory, somatosensory, proprioceptive and vestibular).

Disparity-selective cells in visual cortical neurons have preferred disparities of only a few degrees whereas disparity in natural environments ranges over tens of degrees.

The possible explanation offered by Zhao et al. assumes that animals actively keep disparity within a small range, during development, and therefore only selectivity for small disparity develops.

Zhao et al. present a model of joint development of disparity selectivity and vergence control.

Zhao et al.'s model develops both disparity selection and vergence control in an effort to minimize reconstruction error.

It uses a form of sparse-coding to learn to approximate its input and a variation of the actor-critic learning algorithm called natural actor critic reinforcement learning algorithm (NACREL).

The teaching signal to the NACREL algorithm is the reconstruction error of the model after the action produced by it.

There is a distinction between two different kinds of bats: megabats and microbats. Megabats differ in size (generally), but also in the organization of their visual system. In particular, their retinotectal projections are different: while all of the retinotectal projections in microbats are contralateral, retinotectal projections in megabats are divided such that projections from the nasal part of the retina go to the ipsilateral SC and those from the peripheral part go to the contralateral SC. This is similar to primate vision.

In primates, retinotectal projections to each SC are such that each visual hemifield is mapped to one (contralateral) SC. This is in contrast with retinotectal projections in most other vertebrates, where all projections from one retina project to the contralateral SC.

Antonelli et al. use Bayesian and Monte Carlo methods to integrate optic flow and proprioceptive cues to estimate distances between a robot and objects in its visual field.

The eye suffers from

  • chromatic aberration
  • optical imperfections
  • the fact that photo receptors are behind ganglia and blood vessels

Different wavelengths of light are refracted differently. Therefore, the focal point of the lens is never the same for all wavelengths. Thus, any object can only be perfectly focused in one wavelength partial images in other wavelengths are always blurred. This effect is called chromatic aberration.

Cones are color-sensitive, rods aren't.

Short-range inhibition happens in the horseshoe crab compound eye: neighbouring receptor units inhibit each other.

Cells in the amygdala respond to faces and parts of faces. Some react exclusively to faces.

The M-stream of visual processing is formed by magnocellular ganglion cells, the P-stream by parvocellular ganglion cells.

The M-stream is thought to deal with motion detection and analysis, while the P-stream seems to do be involved in processing color and form.

The part of the visual cortex dedicated to processing signals from the fovea is much greater than that dealing with peripheral signals.

LGN receives more feedback projections from V1 than forward connections from the retina.

Cells in inferotemporal cortex are highly selective to the point where they approach being grandmother cells.

There are cells in inferotemporal cortex which respond to (specific views on / specific parts of) faces, hands, walking humans and others.

"In order to understand a device one needs many different kinds of explanations." To understand vision, one needs theories that comply with the knowledge of the common man, the brain scientist, the experimental psychologist and which can be put to practical use.

The underlying task in vision is to "reliably derive properties of the world from images of it".

Marr speaks of vision as one process, whose task is to generate `a useful description of the world'. However, there is more than one actual goal of vision (though they share similar properties) and thus there are different representations and algorithms being used in the different parts of the brain concerned with these goals.

The retina projects to the superficial SC directly.