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Results for “Discrimination, Psychological”
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Reproduction of horizontal and vertical lines in a within-subjects design.
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Response force as an indicant of conflict in double stimulation.
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Adaptation to sensory-motor conflict produced by the visual direction of the hand specified from the cyclopean eye.
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Differential conditioning of the rabbit's eyelid response with an examination of Pavlov's induction hypothesis.
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Rapid task-related plasticity of spectrotemporal receptive fields in primary auditory cortex.
We investigated the hypothesis that task performance can rapidly and adaptively reshape cortical receptive field properties in accord with specific task demands and salient sensory cues. We recorded neuronal responses in the primary auditory cortex of behaving ferrets that were trained to detect a target tone of any frequency. Cortical plasticity was quantified by measuring focal changes in each cell's spectrotemporal response field (STRF) in a series of passive and active behavioral conditions. STRF measurements were made simultaneously with task performance, providing multiple snapshots of the dynamic STRF during ongoing behavior. Attending to a specific target frequency during the detection task consistently induced localized facilitative changes in STRF shape, which were swift in onset. Such modulatory changes may enhance overall cortical responsiveness to the target tone and increase the likelihood of 'capturing' the attended target during the detection task. Some receptive field changes persisted for hours after the task was over and hence may contribute to long-term sensory memory.
Potentiation of amygdaloid and hippocampal auditory-evoked potentials in a discriminatory fear-conditioning task in mice as a function of tone pattern and context.
According to the local memory storage hypothesis, information about the tone-shock association in an auditory fear-conditioning paradigm is stored in synapses within the lateral amygdala. Thus, fear-conditioning-induced potentiation of auditory-evoked potentials in response to a conditioned stimulus (CS+, a series of short lasting tones; patterned tone) has been interpreted as an in vivo correlate of amygdaloid synaptic plasticity. Here, we re-examine the specificity of potentiation of auditory-evoked potentials in terms of (i) local confinement to the lateral amygdala, (ii) parameters of CS+ and (iii) influence of context, using a discriminatory fear-conditioning paradigm. Adult male C57BL/6J mice were implanted with recording electrodes aimed at the lateral amygdala, the CA1 region of the hippocampus and the neck muscles for simultaneous recordings of auditory-evoked potentials and startle responses. In a neutral context, auditory-evoked potentials within lateral amygdala and CA1 as well as startle and freezing responses to the CS+ were significantly potentiated following conditioning, as compared with pre-conditioning values and responses to a neutral stimulus (CSn; tone of different frequency). Potentiation was only evident if CS+ was presented as a uniform series but not if presented mixed with CSn. Accordingly, mice failed to show intensified freezing to a patterned tone if a single lasting tone of the same frequency served as CS+. Both CA1 and lateral amygdala auditory-evoked potentials were potentiated in response to CSn if presented in the conditioning context. These findings demonstrate that (i) potentiation of auditory-evoked potentials is not restricted to the lateral amygdala, (ii) both tone frequency and pattern of tone presentation are essential for proper CS+ recognition and (iii) contextual memory leads to a general potentiation of auditory-evoked potentials.
Alternative explanations for procedural effects on magnitude-estimation exponents for taste, invoking adaptation, context, and volume effects.
Taste adaptation to residual stimuli from prior tastings was considered along with context and volume effects. These factors are proposed as alternative or supplemental explanations for the differences in the magnitude-estimation exponent (slope of the log-log plot of taste intensity versus solute concentration) that have been obtained by various workers using different stimulus presentation procedures.
Recovery of hearing and vocal behavior after hair-cell regeneration.
Postmitotic hair-cell regeneration in the inner ear of birds provides an opportunity to study the effect of renewed auditory input on auditory perception, vocal production, and vocal learning in a vertebrate. We used behavioral conditioning to test both perception and vocal production in a small Australian parrot, the budgerigar. Results show that both auditory perception and vocal production are disrupted when hair cells are damaged or lost but that these behaviors return to near normal over time. Precision in vocal production completely recovers well before recovery of full auditory function. These results may have particular relevance for understanding the relation between hearing loss and human speech production especially where there is consideration of an auditory prosthetic device. The present results show, at least for a bird, that even limited recovery of auditory input soon after deafening can support full recovery of vocal precision.
Dogmatism and intolerance for sensory discrepancy.
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Differential fear conditioning induces reciprocal changes in the sensory responses of lateral amygdala neurons to the CS(+) and CS(-).
In classical fear conditioning, a neutral sensory stimulus (CS) acquires the ability to elicit fear responses after pairing to a noxious unconditioned stimulus (US). As amygdala lesions prevent the acquisition of fear responses and the lateral amygdaloid (LA) nucleus is the main input station of the amygdala for auditory afferents, the effect of auditory fear conditioning on the sensory responsiveness of LA neurons has been examined. Although conditioning was shown to increase CS-evoked LA responses, the specificity of the changes in responsiveness was not tested. Because conditioning might induce nonspecific increases in LA responses to auditory afferents, we re-examined this issue in conscious, head-restrained cats using a differential conditioning paradigm where only one of two tones (CS(+) but not CS(-)) was paired to the US. Differential conditioning increased unit and field responses to the CS(+), whereas responses to the CS(-) decreased. Such changes have never been observed in the amygdala except in cases where the CS(-) had been paired to the US before and fear responses not extinguished. This suggests that fear conditioning is not only accompanied by potentiation of amygdalopetal pathways conveying the CS(+) but also by the depression of sensory inputs unpaired to noxious stimuli.
Effects of feedback in a forced-choice GSR detection task.
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Some benefits of high frontalis tension in tension headache sufferers.
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Deutsch's model applied to a conditional maze.
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Taste stimuli: a behavioral categorization.
The selective patterns of generalization to various chemicals, obtained in rats after radiation-induced gustatory-avoidance conditioning against single chemicals, were used to evaluate qualitative similarities among taste stimuli. DL-Alanine, glycine, and sodium saccharin were classed together, but not with D-glucose or potassium chloride. Groupings such as these may serve as a basis for determining the dimensions along which taste quality is represented.
Unit activity: motiviation-dependent responses from midbrain neurons.
Single neurons in the midbrain tegmentum of rats showed clear discriminatory responses to three tones announcing either food or water or no reinforcement. Subjects were required to press a single lever and remain motionless for 2 seconds during which time unit activity from several brain sites was recorded. One of the tones, randomly designated, was sounded halfway through this period. Manipulation of drive states revealed that the highest activity was associated with tones announcing the reinforcement for which the animal was most strongly motivated. Thus, from a hungry animal sustained or increased firing rates were elicited by a " food" tone and differentially lowered rates by the other tones.
Evoked response correlate of symbol and significate.
Changing the source and intensity of the auditory signal to six trained cats responding to meaningful auditory stimuli permits exogenous and endogenous processes in the auditory evoked potential to be separated. For short-latency exogenous processes, latency and amplitude depend on the parameters of the physical stimulus. However, the amplitude and shape of longer-latency endogenous processes are essentially independent of the location and intensity of the signal source and seem to be invariant concomitants of the significance of the signal.
An analysis of synthetic processing of odor mixtures in the honeybee (Apis mellifera).
Both sensory transduction and central processing of odor mixtures can give rise to several different kinds of interaction, which can influence how well individual components are perceived and processed. In particular, odor mixtures are believed to give rise to 'configural' or 'synthetic' properties that are not characteristic of the components. However, the exact nature of these effects, particularly with regard to their expression in behavior, remains to be examined in detail. Here we use feature-negative and transwitching conditioning paradigms to show that honeybees can use configural cues in odor processing. However, the nature of these configural cues is not similar to that predicted by some models of conditioning. We propose that configural models may be capable of accounting for a substantial portion of odor mixture processing.