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The Journal of Neuroscience : the... Mar 2022Functional hemispheric lateralization is a basic principle of brain organization. In the auditory domain, the right auditory cortex (AC) determines the pitch direction...
Selective Interruption of Auditory Interhemispheric Cross Talk Impairs Discrimination Learning of Frequency-Modulated Tone Direction But Not Gap Detection and Discrimination.
Functional hemispheric lateralization is a basic principle of brain organization. In the auditory domain, the right auditory cortex (AC) determines the pitch direction of continuous auditory stimuli whereas the left AC discriminates gaps in these stimuli. The involved functional interactions between the two sides, mediated by commissural connections, are poorly understood. Here, we selectively disrupted the interhemispheric cross talk from the left to the right primary AC and vice versa using chromophore-targeted laser-induced apoptosis of the respective projection neurons, which make up 6-17% of all AC neurons in Layers III, V, and VI. Following photolysis, male gerbils were trained in a first experimental set to discriminate between rising and falling frequency-modulated (FM) tone sweeps. The acquisition of the task was significantly delayed in lesioned animals of either lesion direction. However, the final discrimination performance and hit rate was lowest for animals with left-side lesioned commissural neurons, demonstrating that also information from the left AC is relevant for FM direction learning. Photolysis after successful learning did not affect the retrieval of the learned task, indicating that the disruption during learning was not because of a general functional impairment. In a second experimental set, the gerbil's ability to detect and discriminate small silent gaps of varying length within FM sweeps was tested. This ability was also preserved after interhemispheric disruption. Taken together, interhemispheric communication between the left and right AC is important for the acquisition of FM tone direction learning but not for its retrieval and for gap detection and gap duration discrimination. Hemispheric lateralization of neuronal functions such as speech and music processing in humans are common throughout the brain; however, the involved interhemispheric interactions are ill-defined. Here, we show that the selective photolytic disruption of auditory cortical commissural connections in rodents impairs the acquisition but not retrieval of a frequency-modulated tone direction discrimination task. The final discrimination performance and hit rate was lowest for animals with lesioned left-to-right-side projections; thus, although right auditory cortex is dominant, left auditory cortex is also relevant for learning this task. The detection and discrimination of small gaps within the tone sweeps remain intact, suggesting a pathway for the processing of these temporal structures, which could be independent from the lesioned interhemispheric cross talk.
Topics: Acoustic Stimulation; Animals; Auditory Cortex; Discrimination Learning; Gerbillinae; Male; Pitch Discrimination
PubMed: 35064004
DOI: 10.1523/JNEUROSCI.0216-21.2022 -
Journal of Vision 2015Visual perceptual learning has been traditionally characterized by its specificity. Namely, learning transfers little to many untrained stimulus attributes. This result...
Visual perceptual learning has been traditionally characterized by its specificity. Namely, learning transfers little to many untrained stimulus attributes. This result of specificity is the basis for the inference that perceptual learning takes place in low-level visual areas in the brain. Recently, however, Xiao and colleagues (2008) demonstrated a double training technique that enabled complete transfer of learning in all tasks that were tested. This technique has since been applied to motion direction discrimination learning. Learning along one average direction has been found to transfer completely to a new average direction, along which only dot number discrimination had been trained (J. Y. Zhang & Yang, 2014). In the current study, we first repeated the J. Y. Zhang and Yang (2014) experiment in exact procedure, stimuli, and task. We then continued the double training to examine transfer in longer-term perceptual learning. To our surprise, in both our exact replication attempt and in our longer-term learning study, we could not find complete transfer. In fact, the transfer to the dot number discrimination direction was no greater than to an untrained control direction. We suggest that individual differences and subtle differences in experimental setup between J. Y. Zhang and Yang (2014) and our studies are too strong and common to determine whether or not the new double training technique can bring about complete transfer in motion discrimination learning.
Topics: Adult; Discrimination Learning; Female; Humans; Individuality; Male; Motion Perception; Sensitivity and Specificity; Spatial Learning
PubMed: 26230918
DOI: 10.1167/15.10.3 -
Animal Cognition Aug 2022One of the most widely studied abilities in lizards is discrimination learning. The protocols used to test lizards are often novel or adapted from other taxa without...
One of the most widely studied abilities in lizards is discrimination learning. The protocols used to test lizards are often novel or adapted from other taxa without proper validation. We need to ensure that tests of discrimination learning are appropriate and properly applied in lizards so that robust inferences can be made about cognitive ability. Here, we present a new protocol for testing lizard discrimination learning that incorporates a target training procedure, uses many daily trials for efficiency and reinforcement, and has a robust, validated, learning criterion. We trained lizards to touch a cue card using operant conditioning and tested lizards separately on a colour, and pattern discrimination test. Lizards successfully learnt to touch a cue card and to discriminate between light and dark blue but had issues discriminating the patterns. After modifying the test procedure, some lizards reached criterion, revealing possible issues with stimulus processing and interference of generalisation. Here, we describe a protocol for operant conditioning and two-choice discrimination learning in lizards with a robust learning criterion that can help researcher better design future studies on discrimination learning in lizards.
Topics: Animals; Conditioning, Operant; Discrimination Learning; Lizards; Spatial Learning; Visual Perception
PubMed: 35124743
DOI: 10.1007/s10071-022-01603-x -
Neuron Dec 2020Tactile shape recognition requires the perception of object surface angles. We investigate how neural representations of object angles are constructed from sensory input...
Tactile shape recognition requires the perception of object surface angles. We investigate how neural representations of object angles are constructed from sensory input and how they reorganize across learning. Head-fixed mice learned to discriminate object angles by active exploration with one whisker. Calcium imaging of layers 2-4 of the barrel cortex revealed maps of object-angle tuning before and after learning. Three-dimensional whisker tracking demonstrated that the sensory input components that best discriminate angles (vertical bending and slide distance) also have the greatest influence on object-angle tuning. Despite the high turnover in active ensemble membership across learning, the population distribution of object-angle tuning preferences remained stable. Angle tuning sharpened, but only in neurons that preferred trained angles. This was correlated with a selective increase in the influence of the most task-relevant sensory component on object-angle tuning. These results show how discrimination training enhances stimulus selectivity in the primary somatosensory cortex while maintaining perceptual stability.
Topics: Animals; Discrimination Learning; Female; Form Perception; Male; Mice; Mice, Transgenic; Microscopy, Fluorescence, Multiphoton; Touch; Touch Perception; Vibrissae
PubMed: 33002411
DOI: 10.1016/j.neuron.2020.09.012 -
Vision Research Nov 2016Perceptual learning is a phenomenon in which intensive training for a perceptual task may lead to significant improvement in the task performance. So far, the...
Perceptual learning is a phenomenon in which intensive training for a perceptual task may lead to significant improvement in the task performance. So far, the characteristics of the perceptual learning of facial expressions have not been investigated. In the current study, we trained subjects to distinguish facial expressions. With eight days of training, the subjects' discrimination performance improved significantly, and this improvement was generalized to faces with the same expression but different gender as the trained face. In the second experiment, we further examined the transfer of the learning effect between faces with different expression intensities. We found that the learning effect of happiness can be transferred from the high-intensity face to the low-intensity face, but the reverse was not true. Importantly, in all experiments, we measured the performance immediately after training and one month after training. The results showed that all learning effects and transfers were able to persist for at least one month, which implied that these findings revealed the long-term mechanisms of training. These results revealed the characteristics of facial expression learning and shed light on the mechanisms of perceptual learning for high-level vision.
Topics: Adolescent; Adult; Analysis of Variance; Discrimination Learning; Facial Expression; Female; Happiness; Humans; Male; Pattern Recognition, Visual; Sex Factors; Young Adult
PubMed: 27664348
DOI: 10.1016/j.visres.2016.08.005 -
Journal of Experimental Psychology.... Jul 2019Animals optimize their behavior to maximize rewards by utilizing cues from the environment. In discrimination learning, cues signal when rewards can and cannot be earned...
Animals optimize their behavior to maximize rewards by utilizing cues from the environment. In discrimination learning, cues signal when rewards can and cannot be earned by making a particular response. In our experiment, we trained male mice to press a lever to receive a reward on a random interval schedule. We then introduced a prolonged tone (20, 40, or 80 sec), during which no rewards could be earned. We sought to test our hypothesis that the duration of the tone and frequency of reward during the inter-tone-intervals affect the informativeness of cues and led to differences in discriminative behavior. Learning was expressed as an increase in lever pressing during the intertrial interval (ITI) and, when the informativeness of the cue was high, animals also reduced their lever pressing during the tone. Additionally, we found that the depth of discriminative learning was linearly related to the informativeness of the cues. Our results show that the time-scale invariant information-theoretic definition of contingency applied to excitatory conditioning can also be applied to inhibitory conditioning. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
Topics: Acoustic Stimulation; Animals; Behavior, Animal; Conditioning, Operant; Cues; Discrimination Learning; Male; Mice; Reward; Time Factors
PubMed: 31021132
DOI: 10.1037/xan0000205 -
The Journal of Neuroscience : the... May 2021Theoretical and modeling studies demonstrate that heterosynaptic plasticity-changes at synapses inactive during induction-facilitates fine-grained discriminative...
Theoretical and modeling studies demonstrate that heterosynaptic plasticity-changes at synapses inactive during induction-facilitates fine-grained discriminative learning in Hebbian-type systems, and helps to achieve a robust ability for repetitive learning. A dearth of tools for selective manipulation has hindered experimental analysis of the proposed role of heterosynaptic plasticity in behavior. Here we circumvent this obstacle by testing specific predictions about the behavioral consequences of the impairment of heterosynaptic plasticity by experimental manipulations to adenosine A1 receptors (A1Rs). Our prior work demonstrated that the blockade of adenosine A1 receptors impairs heterosynaptic plasticity in brain slices and, when implemented in computer models, selectively impairs repetitive learning on sequential tasks. Based on this work, we predict that A1R knock-out (KO) mice will express (1) impairment of heterosynaptic plasticity and (2) behavioral deficits in learning on sequential tasks. Using electrophysiological experiments in slices and behavioral testing of animals of both sexes, we show that, compared with wild-type controls, A1R KO mice have impaired synaptic plasticity in visual cortex neurons, coupled with significant deficits in visual discrimination learning. Deficits in A1R knockouts were seen specifically during relearning, becoming progressively more apparent with learning on sequential visual discrimination tasks of increasing complexity. These behavioral results confirm our model predictions and provide the first experimental evidence for a proposed role of heterosynaptic plasticity in organism-level learning. Moreover, these results identify heterosynaptic plasticity as a new potential target for interventions that may help to enhance new learning on a background of existing memories. Understanding how interacting forms of synaptic plasticity mediate learning is fundamental for neuroscience. Theory and modeling revealed that, in addition to Hebbian-type associative plasticity, heterosynaptic changes at synapses that were not active during induction are necessary for stable system operation and fine-grained discrimination learning. However, lacking tools for selective manipulation prevented behavioral analysis of heterosynaptic plasticity. Here we circumvent this barrier: from our prior experimental and computational work we predict differential behavioral consequences of the impairment of Hebbian-type versus heterosynaptic plasticity. We show that, in adenosine A1 receptor knock-out mice, impaired synaptic plasticity in visual cortex neurons is coupled with specific deficits in learning sequential, increasingly complex visual discrimination tasks. This provides the first evidence linking heterosynaptic plasticity to organism-level learning.
Topics: Animals; Discrimination Learning; Female; Male; Mice; Mice, Knockout; Neuronal Plasticity; Receptor, Adenosine A1; Visual Cortex
PubMed: 33849950
DOI: 10.1523/JNEUROSCI.3073-20.2021 -
Cell Reports May 2024Changes in sound-evoked responses in the auditory cortex (ACtx) occur during learning, but how learning alters neural responses in different ACtx subregions and changes...
Changes in sound-evoked responses in the auditory cortex (ACtx) occur during learning, but how learning alters neural responses in different ACtx subregions and changes their interactions is unclear. To address these questions, we developed an automated training and widefield imaging system to longitudinally track the neural activity of all mouse ACtx subregions during a tone discrimination task. We find that responses in primary ACtx are highly informative of learned stimuli and behavioral outcomes throughout training. In contrast, representations of behavioral outcomes in the dorsal posterior auditory field, learned stimuli in the dorsal anterior auditory field, and inter-regional correlations between primary and higher-order areas are enhanced with training. Moreover, ACtx response changes vary between stimuli, and such differences display lag synchronization with the learning rate. These results indicate that learning alters functional connections between ACtx subregions, inducing region-specific modulations by propagating behavioral information from primary to higher-order areas.
Topics: Auditory Cortex; Animals; Discrimination Learning; Mice; Acoustic Stimulation; Auditory Perception; Male; Female; Mice, Inbred C57BL; Evoked Potentials, Auditory
PubMed: 38703366
DOI: 10.1016/j.celrep.2024.114172 -
PloS One 2016Perceptual training is generally assumed to improve perception by modifying the encoding or decoding of sensory information. However, this assumption is incompatible...
Perceptual training is generally assumed to improve perception by modifying the encoding or decoding of sensory information. However, this assumption is incompatible with recent demonstrations that transfer of learning can be enhanced by across-trial variation of training stimuli or task. Here we present three lines of evidence from healthy adults in support of the idea that the enhanced transfer of auditory discrimination learning is mediated by working memory (WM). First, the ability to discriminate small differences in tone frequency or duration was correlated with WM measured with a tone n-back task. Second, training frequency discrimination around a variable frequency transferred to and from WM learning, but training around a fixed frequency did not. The transfer of learning in both directions was correlated with a reduction of the influence of stimulus variation in the discrimination task, linking WM and its improvement to across-trial stimulus interaction in auditory discrimination. Third, while WM training transferred broadly to other WM and auditory discrimination tasks, variable-frequency training on duration discrimination did not improve WM, indicating that stimulus variation challenges and trains WM only if the task demands stimulus updating in the varied dimension. The results provide empirical evidence as well as a theoretic framework for interactions between cognitive and sensory plasticity during perceptual experience.
Topics: Acoustic Stimulation; Adolescent; Adult; Auditory Perception; Cognition; Discrimination Learning; Female; Humans; Learning; Male; Memory, Short-Term; Young Adult
PubMed: 26799068
DOI: 10.1371/journal.pone.0147320 -
Experimental Brain Research Nov 2018The zebrafish is a model organism to study olfactory information processing, but efficient behavioral procedures to analyze olfactory discrimination and memory are...
The zebrafish is a model organism to study olfactory information processing, but efficient behavioral procedures to analyze olfactory discrimination and memory are lacking. We devised an automated odor discrimination task for adult zebrafish based on olfactory conditioning of feeding behavior. Presentation of a conditioned odor (CS+), but not a neutral odor (CS-) was followed by food delivery at a specific location. Fish developed differential behavioral responses to CS+ and CS- within a few trials. The behavioral response to the CS+ was complex and included components reminiscent of food search such as increased swimming speed and water surface sampling. Appetitive behavior was therefore quantified by a composite score that combined measurements of multiple behavioral parameters. Robust discrimination behavior was observed in different strains, even when odors were chemically similar, and learned preferences could overcome innate odor preferences. These results confirm that zebrafish can rapidly learn to make fine odor discriminations. The procedure is efficient and provides novel opportunities to dissect the neural mechanisms underlying olfactory discrimination and memory.
Topics: Animals; Conditioning, Classical; Discrimination Learning; Feeding Behavior; Female; Male; Odorants; Olfactory Perception; Smell; Zebrafish
PubMed: 30088022
DOI: 10.1007/s00221-018-5352-x