Receptive fields and functional architecture in the retina
AUTOR(ES)
Balasubramanian, Vijay
FONTE
Blackwell Science Inc
RESUMO
Functional architecture of the striate cortex is known mostly at the tissue level – how neurons of different function distribute across its depth and surface on a scale of millimetres. But explanations for its design – why it is just so – need to be addressed at the synaptic level, a much finer scale where the basic description is still lacking. Functional architecture of the retina is known from the scale of millimetres down to nanometres, so we have sought explanations for various aspects of its design. Here we review several aspects of the retina's functional architecture and find that all seem governed by a single principle: represent the most information for the least cost in space and energy. Specifically: (i) why are OFF ganglion cells more numerous than ON cells? Because natural scenes contain more negative than positive contrasts, and the retina matches its neural resources to represent them equally well; (ii) why do ganglion cells of a given type overlap their dendrites to achieve 3-fold coverage? Because this maximizes total information represented by the array – balancing signal-to-noise improvement against increased redundancy; (iii) why do ganglion cells form multiple arrays? Because this allows most information to be sent at lower rates, decreasing the space and energy costs for sending a given amount of information. This broad principle, operating at higher levels, probably contributes to the brain's immense computational efficiency.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2718235Documentos Relacionados
- Physiological responses, receptive fields and terminal arborizations of nociceptive cells in the leech.
- Plasticity in the binocular correspondence of striate cortical receptive fields in kittens.
- Receptive fields and in-field afferent inhibition of neurones in the cat's lateral cervical nucleus.
- The effect of dynamic synapses on spatiotemporal receptive fields in visual cortex
- Cutaneous inhibitory receptive fields of withdrawal reflexes in the decerebrate spinal rat.