Perceptually unidentifiable stimuli influence cortical processing and behavioral performance

Our daily behavior is dynamically influenced by conscious and unconscious processes. Although the neural bases of conscious experience have been extensively investigated over the past several decades, how unconscious information impacts neural circuitry and behavior remains unknown. Here, we recorded populations of neurons in macaque primary visual cortex (V1) to find that perceptually unidentifiable stimuli repeatedly presented in the absence of awareness are encoded by neural populations in a way that facilitates their future processing in the context of a behavioral task. Such exposure increases stimulus sensitivity and information encoded in cell populations, even though animals are unaware of stimulus identity. This phenomenon is consistent with a Hebbian mechanism underlying an increase in functional connectivity specifically for the neurons activated by subthreshold stimuli. This form of unsupervised adaptation may constitute a vestigial pre-attention system using the mere frequency of stimulus occurrence to change stimulus representations even when sensory inputs are perceptually invisible.

Behavior Modification In The Treatment Of Obesity

This review addresses the three most common components used in helping individuals deal with weight loss from a behavioral perspective. Relevant literature and recent findings are reviewed and summarized, showing that programs containing behavioral techniques, along with an emphasis on diet and exercise, tend to lead to improved results. Factors related to better weight loss outcomes include assessing empathically, setting reasonable goals, enhancing a sense of self-determination, seeing a patient more frequently, focusing on decreasing caloric intake, and encouraging regular physical activity. Newer technologies, such as Internet- and smartphone-based interventions, seem promising but lack sufficient research evidence at this point. It is also clear that just as reasons for weight gain are patient specific, treatments likely do best when they are more highly individualized. This review contains 3 figures, 2 tables and 33 references Key words: behavior, cognitive restructuring, decision tree, 5As, intervention, mindfulness, modification, motivation, obesity, relapse prevention, self-monitoring, stages of change, stimulus control, treatment, weight loss

The “Heart” of Categorical Speech Discrimination in Young Infants

Categorical discrimination of place of articulation in the stimuli [dae] and [gae] was investigated in three- to four-month-old infants using a 20/20 cardiac orienting response paradigm. In this procedure infants were presented with 20 tokens of one syllable followed immediately by 20 tokens of a change stimulus. Each infant received a between-category shift, a within-category shift, and a no-shift control condition, with the order of conditions completely counterbalanced across subjects. Discrimination was indexed by an orienting response to the onset of the second 20 stimuli. The data were analyzed for evidence of categorical discrimination both within subjects (each condition pooled across orders of presentation) and between subjects, as is typical of infant-categorical discrimination studies. Both sets of results revealed that infants discriminate the cues for place of articulation categorically. These findings demonstrate the generality of the infant categorical discrimination observed with the nonnutritive operant sucking paradigm and indicate the usefulness of the heart rate paradigm employed in the present study for the collection of within-subject speech discrimination data across a wide range of subject populations.