Biology subjects

Maor, I.

Publications and source records attributed to Maor, I..

5 recordsLinked to original sources

bioRxiv2025

Persistent representation of a prior schema in the orbitofrontal cortex facilitates learning of a conflicting schema

Schemas allow efficient behavior in new situations, but reliance on them can impair flexibility when new demands conflict, culminating in psychopathology. Evidence implicates the orbitofrontal cortex (OFC) in deploying schemas in new situations congruent with previously acquired knowledge. But how does this role affect learning of a conflicting behavioral schema? Here we addressed this question by recording single-unit activity in the OFC of rats learning odor problems with identical external information but orthogonal rules governing reward. Consistent with schema formation, OFC representations adapted to track the underlying rules, and both performance and encoding was faster on subsequent than initial problems. Surprisingly however, when the rule governing reward changed, persistent representation of the prior schema was correlated with acquisition of the new. Thus, OFC was not a source of interference and instead supported new learning by accurately and independently representing the old schema as the new was acquired.

neuroscience↗

bioRxiv2023

Aberrant circuitry underlying olfaction in the face of severe olfactory bulb degeneration

The olfactory bulb (OB) is a critical component of mammalian olfactory neuroanatomy. Beyond being the first and sole relay station for olfactory information to the rest of the brain, it also contains elaborate stereotypical circuitry that is considered essential for olfaction. Indeed, substantial lesions of the OB in rodents lead to anosmia. Here, we examined the circuitry that underlies olfaction in a mouse model with severe developmental degeneration of the OB. These mice could perform odor-guided tasks and even responded normally to innate olfactory cues. Despite the near total loss of the OB, piriform cortex in these mice responded to odors normally and its neural activity sufficed to decode odor identity. We analyzed the circuitry that supports olfactory function in these mice. We found that sensory neurons express the full repertoire of olfactory receptors and their axons project primarily to the rudimentary OB, but also ectopically, to olfactory cortical regions. Within the OB, the number of principal neurons was greatly reduced and the morphology of their dendrites was abnormal, extending over larger regions within the OB. Glomerular organization was lost. This study shows that olfactory functionality can be preserved despite reduced and aberrant circuitry that is missing many of the elements that are believed to be essential for olfaction, and may explain the retention of olfaction in humans with degenerated OBs.

neuroscience↗

bioRxiv2020

Sparse Coding in Temporal Association Cortex Improves Complex Sound Discriminability

The mouse auditory cortex is comprised of several auditory fields spanning the dorso-ventral axis of the temporal lobe. The ventral most auditory field is the temporal association cortex (TeA), which remains largely unstudied. Using Neuropixels probes, we simultaneously recorded from primary auditory cortex (AUDp), secondary auditory cortex (AUDv) and TeA, characterizing neuronal responses to pure tones and frequency modulated (FM) sweeps in awake head-restrained mice. As compared to primary and secondary auditory cortices, single unit responses to pure tones in TeA were sparser, delayed and prolonged. Responses to FMs were also sparser. Population analysis showed that the sparser responses in TeA render it less sensitive to pure tones, yet more sensitive to FMs. When characterizing responses to pure tones under anesthesia, the distinct signature of TeA was changed considerably as compared to that in awake mice, implying that responses in TeA are strongly modulated by non-feedforward connections. Together with the known connectivity profile of TeA, these findings suggest that sparse representation of sounds in TeA supports selectivity to higher-order features of sounds and more complex auditory computations.

neuroscience↗

bioRxiv2020

Learning-related population dynamics in the auditory thalamus

Learning to associate sensory stimuli with a chosen action has been classically attributed to the cortex. Whether the thalamus, considered mainly as an upstream area relative to cortex, encodes learning-related information is still largely unknown. We studied learning-related activity in the dorsal and medial regions of the medial geniculate body (MGB), part of the non-lemniscal auditory pathway. Using fiber photometry, we continuously imaged population calcium dynamics as mice learned a go/no-go auditory discrimination task. The MGB was tuned to frequency shortly after stimulus onset and responded to cognitive features like the choice of the mouse several hundred milliseconds later. Encoding of choice in the MGB increased with learning, and was highly correlated with the learning curves of the mice. MGB also encoded motor parameters of the mouse during the task. These results provide evidence that the MGB encodes task- motor- and learning-related information.

neuroscience↗

bioRxiv2018

The Educage: an automated platform for studying auditory perceptual learning in mice

Auditory perceptual learning of pure tones causes tonotopic map expansion in the primary auditory cortex (A1), but the function this plasticity sub-serves is unclear. We developed an automated training platform called the Educage, which was used to train mice on a go/no-go auditory discrimination task to their perceptual limits, for difficult discriminations among pure tones or natural sounds. Spiking responses of excitatory and inhibitory L2/3 neurons in mouse A1 revealed learning-induced overrepresentation of the learned frequencies, in accordance with previous literature. Using a novel computational model to study auditory tuning curves we show that overrepresentation does not necessarily improve discrimination performance of the network to the learned tones. In contrast, perceptual learning of natural sounds induced sparsening and decorrelation of the neural response, and consequently improving discrimination of these complex sounds. The signature of plasticity in A1 highlights its central role in coding natural sounds as compared to pure tones.

animal behavior and cognition↗