Consciously detecting and recognizing a stimulus without knowing what it looks like

Does conscious perception occur during initial sensory processing, or does it arise later in a supra modal fashion? If conscious access truly depends on supra modal processes, we may be able to induce “asensory perception”, where only the semantic features of a meaningful stimulus are accessed, untied to its sensory attributes. Here we tested this prediction by degrading the low-level sensory representations of visual words in the brain using pattern masking, and subsequently presenting audio words that were either semantically related to the masked word or not. We hypothesized these retrospective semantic cues would reactivate the remaining traces of the masked word in the brain, and induce awareness of any information that was not disrupted by masking. In three separate experiments we show that, when presented with retrospective cues that are semantically related to the masked word, participants are better at detecting the presence of the preceding masked word and naming it, while at the same time being unable to report its visual features. In other words, participants could consciously detect and recognize the preceding masked word, without knowing what it looked like. These findings suggest that non-sensory information can be consciously accessed in relative independence from the build-up of sensory representations.

Eliciting motor responses through pavlovian conditioning

Classical conditioning theory involves learning a new behaviour through the process of association. In simple terms, two stimuli are linked together to produce a newly learned response in a person or animal. It is the process of associating, and consequently, providing meaning to a neutral stimulus with another meaningful stimulus, in order to elicit similar response and the basic processes that occur in classical conditioning include acquisition, stimulus generalisation, stimulus discrimination, and extinction. It is, in fact, no doubt that Pavlovian theory is also known as the theory of classical conditioning has an impeccable illustration of associative learning, this paper attempts to depict its application to learning motor skills as well as to critically evaluate its influence in sports.

Acute Optogenetic Modulation of Cardiac Twitch Dynamics Explored Through Modeling

Optogenetic approaches allow cellular membrane potentials to be perturbed by light. When applied to muscle cells, mechanical events can be controlled through a process that could be termed “optomechanics.” Besides functioning as an optical on/off switch, we hypothesized that optomechanical control could include the ability to manipulate the strength and duration of contraction events. To explore this possibility, we constructed an electromechanical model of the human ventricular cardiomyocyte while adding a representation of channelrhodopsin-2 (ChR2), a light-activated channel commonly used in optogenetics. Two hybrid stimulus protocols were developed that combined light-based stimuli with traditional electrical current (all-or-none) excitation. The first protocol involved delivery of a subthreshold optical stimulus followed 50–90 ms later by an electrical stimulus. The result was a graded inhibition of peak cellular twitch force in concert with a prolongation of the intracellular Ca2+ transient. The second protocol was comprised of an electrical stimulus followed by a long light pulse (250–350 ms) that acted to prolong the cardiac action potential (AP). This created a pulse duration-dependent prolongation of the intracellular Ca2+ transient that in turn altered the rate of muscle relaxation without changing peak twitch force. These results illustrate the feasibility of acute, optomechanical manipulation of cardiomyocyte contraction and suggest that this approach could be used to probe the dynamic behavior of the cardiac sarcomere without altering its intrinsic properties. Other experimentally meaningful stimulus protocols could be designed by making use of the optomechanical cardiomyocyte model presented here.

Individual Differences in the Wegner Rebound Effect: Evidence for a Moderator Variable in Thought Rebound following Thought Suppression

Wegner, Schneider, Carter, and White in 1987 found that attempts to suppress thoughts of a white bear produced even greater preoccupation with that stimulus—a rebound effect. This effect was investigated in Exp. 1 using both Wegner's white bear stimulus and a more personally meaningful stimulus (an upcoming test). The rebound effect was not observed with either stimulus. Exp. 2 was conducted to examine the hypothesis that this failure to replicate Wegner, et al.'s rebound effect reflected individual differences in the respective subject pools. A within-subjects design was used to classify subjects as rebounders or nonrebounders by comparing each subject's expression of a thought following suppression to their own baseline expression of that thought. Subjects classified as rebounders had significantly higher ACT Mathematics subtest scores than did the subjects classified as nonrebounders. This suggests that there is a moderator variable related to mathematics ability for the rebound effect.

“Contingent Negative Variation” in Rhesus Monkeys: An EEG Sign of a Specific Mental Process

Utilizing long time-constant EEG recording techniques, magnetic tape storage, and electronic averaging, the phenomenon designated the “contingent negative variation” or “expectancy wave” was studied in 3 Rhesus monkeys. Three basic conditioning paradigms were used: escape conditioning with a warning cue, discrimination task with aversive reinforcement following SD, and discrimination with appetitive reinforcement. Trials were presented in blocks of 12 and averaged on line with an Enhancetron electronic averager. In each case, during acquisition trials, a surface negative slow potential gradually developed only following the evoked response to SD and preceding the meaningful stimulus. No shift followed the unreinforced stimulus. During extinction trials, the shift gradually diminished. During discrimination reversal, a negative shift developed following the previously unreinforced stimulus, while the shift following what had been SD gradually diminished. Results demonstrate the appearance of the “contingent negative variation” in these monkeys and support the contention that this shift is a result of cerebral electrical activity during conation.

Semantic Description of Complex and Meaningful Stimulus Material

A collection of photographic portraits was judged with the aid of Osgood's semantic differential. The data were factor analysed, and two dimensions emerged which could be associated with Osgood's “evaluation” and “dynamism” factors.

Time Estimation as an Indicator of Attention-Arousal When Perceiving Complex and Meaningful Stimulus Material

The covariation between time estimation and simultaneous perception of visual stimuli chosen to evoke different amounts of attention-arousal was studied. Pictures with high attention-value or arousal potential slowed the conscious internal clock as compared with more neutral pictures. The loss of attention-value in the loaded pictures after prolonged confrontation could be observed in Ss' time estimations. At the end of the experimental session the difference between pictures with initially different attention-values disappeared in the time estimations.