The role of the primate middle temporal area (MT) in depth perception was examined by considering trial-to-trial correlations between neuronal activity and reported sensations. A set moving random dots portrayed a cylinder rotating about its principal axis. In this structure-from-motion stimulus, direction rotation is ambiguous resulting percept undergoes spontaneous fluctuations. stimulus can be rendered unambiguous addition binocular disparities. We trained monkeys to report these stimuli,...

We recorded from neurons dorsal and dorsolateral to the third nerve nucleus of monkey whose discharge rates modulated when tracked targets moving in depth but not it side side. The neurons' activity equally well whether target moved directly toward one eye or other. For most amplitude modulation was similar monocularly (blur cue alone), binocularly with accommodation open-loop (disparity normal binocular viewing. By comparing viewing that blur disparity cues were conflict we able show 19...

Most neurophysiological accounts of disparity selectivity in neurons the primary visual cortex (V1) imply that they are selective for absolute retinal disparities. By contrast, a number psychophysical observations indicate relative disparities play more important role depth perception. During recordings from area V1 awake behaving monkeys, we used feedback loop (Rashbass and Westheimer, 1961) to add controlled amounts display containing both This manipulation changed all visible features but...

Horizontal disparity tuning for dynamic random-dot stereograms was investigated a large population of neurons ( n = 787) in V1 the awake macaque. Disparity sensitivity quantified using measure discriminability maximum and minimum points on curve. This others revealed continuum selectivity rather than separate populations disparity- nondisparity-sensitive neurons. Although correlated with degree direction tuning, it not other significant neuronal properties, including preferred orientation...

The responses of single cortical neurons were measured as a function the binocular disparity dynamic random dot stereograms for large sample ( n = 787) from V1 awake macaque. From this sample, we selected 180 whose tuning curves strongly tuned disparity, well sampled and described by one-dimensional Gabor functions. fitted parameters functions used to resolve three outstanding issues in stereopsis. First, considered whether can be meaningfully divided into discrete types. Careful examination...

In Chenopodium botrys, darkness was suboptimal for germination at all temperatures. At low to intermediate temperatures (10 20 °C) short photoperiods were optimal while longer ones supraoptimal. high (25° 35 extremely long and shorter suboptimal. There less in light of than red far-red (R/FR) spectral energy ratios, particularly photoperiods. Decreasing the R/FR ratio terminal 30 minutes daily restricted considerably but not extreme (18 hours). It is postulated that sub- supra-optimal...

Abstract Saccadic eye movements play a central role in primate vision. Yet, relatively little is known about their effects on the neural processing of visual inputs. Here we examine this question primary cortex (V1) using receptive-field-based models, combined with an experimental design that leaves retinal stimulus unaffected by saccades. This approach allows us to analyse V1 during saccades unprecedented detail, revealing robust perisaccadic modulation. In particular, produce biphasic...

Neurons throughout the brain modulate their firing rate lawfully in response to sensory input. Theories of neural computation posit that these modulations reflect outcome a constrained optimization which neurons aim robustly and efficiently represent information. Our understanding how this varies across different areas brain, however, is still its infancy. Here, we show responses transform along dorsal stream visual system manner consistent with transition from optimizing for information...

Binocular neurons that are closely related to depth perception should respond selectively for stimuli eliciting an appropriate sensation. To separate perceived from local disparity within the receptive field, sinusoidal luminance gratings were presented a circular aperture. The of aperture was coupled grating, thereby rendering unambiguous psychophysical matching between repeating cycles grating. In cases in which stimulus differs by one horizontal period portion grating locally covers field...

In the macaque extrastriate cortex, robust correlations between perceptual choice and neuronal response have been demonstrated, frequently quantified as probabilities (CPs). Such are modest in early visual suggesting that CPs may depend on position of a neuron hierarchy processing. However, previous studies not compared neurons with similar precision equivalent tasks. We investigated role cortical CP using task for which significant described previously middle temporal area (MT). measured...

Tremendous progress has been made on molecular aspects of plant phosphorus (P) nutrition, often without heeding information provided by soil scientists, ecophysiologists, and crop physiologists. This review suggests ways to integrate from ... Read More

Flowering of Chenopodium rubrum L., selection 374, was examined with respect to an endogenous circadian rhythm, the state phytochrome, and result changing form phytochrome during a single dark period 2 96 hours interrupting continuous light. Darkness imposed either 4 or 5 days after seeds were placed on moist filter paper in Petri dishes.The following working hypothesis, which is partly retrospective, projected explain main features experimental results. controlled by product enzymatic...

Many studies have reported correlations between the activity of sensory neurons and animals' judgments in discrimination tasks. Here, we suggest that such neuron-behavior may require a cortical map for task relevant features. This would explain why using tasks based on disparity area V1 not found these correlations: contains no disparity. scheme predicts correlates with decisions an orientation-discrimination task. To test this prediction, trained two macaque monkeys coarse orientation...