http://www.ncbi.nlm.nih.gov/pubmed/24598528

QUOTE

J Neurophysiol. 2014 Mar 5. [Epub ahead of print]

Emerging feed-forward inhibition allows the robust formation of
direction selectivity in the developing ferret visual cortex.

Van Hooser SD1, Escobar GM, Maffei A, Miller P.
Author information

Abstract
The computation of direction selectivity requires that a cell respond
to joint spatial and temporal characteristics of the stimulus that
cannot be separated into independent components. Direction selectivity
in ferret visual cortex is not present at the time of eye opening,
but instead develops in the days and weeks following eye opening in a
process that requires visual experience with moving stimuli. Classic
Hebbian or spike-timing-dependent modification of excitatory
feed-forward synaptic inputs is unable to produce direction-selective
cells from unselective or weakly directionally biased initial
conditions because inputs eventually grow so strong that they can
independently drive cortical neurons, violating the joint
spatial-temporal activation requirement. Further, without some form
of synaptic competition, cells cannot develop direction selectivity
in response to training with bidirectional stimulation, as cells in
ferret visual cortex do. We show that imposing a maximum LGN-to-cortex
synaptic weight allows neurons to develop direction-selective
responses that maintain the requirement for joint spatial and temporal
activation. We demonstrate that a novel form of inhibitory plasticity,
post-synaptic activity-dependent long term potentiation of inhibition
(POSD-LTPi), which operates in the developing cortex at the time
of eye opening, can provide synaptic competition and enables robust
development of direction-selective receptive fields with unidirectional
or bidirectional stimulation. We propose a general model of the
development of spatiotemporal receptive fields that consists of 2
phases: an experience-independent establishment of initial biases,
followed by an experience-dependent amplification or modification of
these biases via correlation-based plasticity of excitatory inputs
that compete against gradually increasing feed-forward inhibition.

KEYWORDS:
Feedforward, Hebbian, Reichardt detector, spatiotemporal, unsupervised

PMID: 24598528 [PubMed - as supplied by publisher]

END QUOTE

Most ferret hunting happens in dark burrows, though polecats in some
areas have frogs as a major dietary component, and other types of food
sources typically found in crepuscular (low light) situations. Except
for hunting done in darkness the visual ability discussed above is
important for hunting, so this info might affect some choices in how
BFFs or hunting ferrets are raised.

There is still a lot being learned about ferret vision which disproves
quite a bit of previous "general knowledge". For example, domestic
ferrets have two types of cones, ones that are used to detect short
wavelengths AND ones used to detect long wavelengths. Also, albinos
have multiple visual shortfalls compared to ferrets with standard
pelage.

[Posted in FML 8061]