Biology subjects

Burwell, R. D.

Publications and source records attributed to Burwell, R. D..

7 recordsLinked to original sources

bioRxiv2024

Information transfer from spatial to social distance in rats: implications for the role of the posterior parietal cortex in spatial-social integration

Humans and other social animals can represent and navigate complex networks of social relationships in ways that are suggestive of representation and navigation in space. There is some evidence that cortical regions initially required for processing space have been adapted to include processing of social information. One candidate region for supporting both spatial and social information processing is the posterior parietal cortex (PPC). We examined the hypothesis that rats can transfer or generalize distance information across spatial and social domains and that this phenomenon requires the PPC. In a novel apparatus, rats learned to discriminate two conspecifics positioned at different spatial distances (near vs. far) in a goal-driven paradigm. Following spatial learning, subjects were tested on probe trials in which spatial distance was replaced with social distance (cagemate vs. less familiar conspecific). The PPC was chemogenetically inactivated during a subset of probe sessions. We predicted that, in control probe trials, subjects would select conspecifics whose social distance matched the previously learned spatial distance. That is, if trained on the near distance, the rat would choose the highly familiar cagemate, and if trained on the far distance, the rat would choose the less familiar conspecific. Subjects learned to discriminate conspecifics based on spatial distance in our goal-driven paradigm. Moreover, choice for the appropriate social distance in the first probe session was significantly higher than chance. This result suggests that rats transferred learned spatial information to social contexts. Contrary to our predictions, PPC inactivation did not impair spatial to social information transfer. Possible reasons are discussed. To our knowledge, this is the first study to provide evidence that spatial and social distance are processed by shared cognitive mechanisms in the rat model.

neuroscience↗

bioRxiv2024

A novel behavioral apparatus for spontaneous exploration and operant conditioning of social information under spatial conditions in rats

BackgroundEvidence from the fields of evolutionary biology and neuroscience supports the theory that spatial cognition and social cognition share neural mechanisms. Rodent models are widely used to study either spatial or social cognition, but few studies have explored the interactions between the spatial and social cognitive domains due to the lack of appropriate paradigms. New methodOur study introduces the Vertical Maze (VM), a novel behavioral apparatus designed to measure multiple aspects of spatial and social cognition. The VM features a standard 3-chamber maze positioned above multilevel columns allowing for the presentation of conspecifics at varying spatial distances and familiarity levels. This arrangement enables conspecifics to serve as discriminative stimuli for both social and spatial spontaneous and goal-oriented assessments. The three-dimensional design of the VM allows rats to use multisensory cues to judge distance, direction, and social identity of conspecifics. ResultsIn the present study, we found that rats can 1) discriminate the spatial distance of conspecifics located below them in an operant conditioning task, and 2) discriminate social novelty when conspecifics are presented below at the near, middle, and far distances in a spontaneous exploration task. Critically, it was necessary for rats to explore all levels of the maze to perform these discriminations. Comparison with existing methodsThis new method advances the field by permitting the presentation of social information (conspecifics) at different spatial distances. The use of conspecifics to serve as stimuli for both social and spatial discriminations allows more direct comparison of behavioral measures across these information domains. Importantly, the presentation of conspecifics as stimuli below the 3-chamber level of the maze engages auditory, visual, and olfactory systems, encouraging a robust multisensory representation of conspecifics presented at a distance. ConclusionsOur results confirm that the VM is an effective tool for studying both spatial and social cognition, facilitating the development of novel automated tasks in these areas. This new method opens new avenues for investigating the neural and cognitive foundations of spatial and social behavior, as well as for exploring the possibility of shared mechanisms across these cognitive domains.

animal behavior and cognition↗

bioRxiv2024

Pulvinar perturbation causes functional reorganization of visual attentional information in posterior parietal cortex

The pulvinar nucleus of the thalamus (PUL) is a higher-order thalamic relay and the main visual extrageniculate thalamic nucleus. Evidence suggests the PUL coordinates information processing across cortical areas involved in visual perception and attention. Other findings suggest the PUL may also influence higher-order cognitive processes, such as attentional control, through interactions with connected neocortical areas like the posterior parietal cortex (PPC). We hypothesized that PUL input to the dorsal and caudal PPC (DPPC and CPPC) enhances visuospatial processing and attention. To test this hypothesis, we recorded neuronal activity in the PUL, DPPC, and CPPC of freely behaving rats performing the visuospatial attention (VSA) task while optogenetically suppressing PUL neurons on some trials. We found that PUL manipulation did not affect behavioral performance, but reorganized neural codes in DPPC and CPPC as well as PUL itself.

animal behavior and cognition↗

bioRxiv2024

Perirhinal and postrhinal cortices are necessary for retrieving latently-acquired stimulus associations

The perirhinal and postrhinal cortices reside in the parahippocampal region of the medial temporal lobe. They receive and process sensory information from cortical and subcortical sources and support hippocampal functions via direct connectivity and indirectly via the entorhinal cortex. Previous studies using the sensory preconditioning paradigm have shown that the perirhinal and postrhinal cortices are necessary for associating cues during preconditioning and retrieving the associations during conditioning. However, the question of whether these regions are also required for stimulus association retrieval during re-exposure to the preconditioning cue had not been addressed. Using a chemogenetic approach, we temporarily suppressed the perirhinal or postrhinal cortex in adult male rats during the preconditioning cue test phase. Both suppression groups showed impaired sensory preconditioning compared to sham surgery controls, as indicated by significantly reduced preferential responding. Implications of our findings are discussed in relation to the importance of the PER and POR in context processing and episodic-like memory in animal models. Significance statementAlthough Pavlovian conditioning between two stimuli is widely used in neuroscience, associative learning in the real-world is often too complex to be modeled by first-order conditioning alone. Proper responding may require integrating multiple associations via common elements, i.e. higher-order conditioning, the neural basis of which is not well understood. Whereas existing research indicates the perirhinal and postrhinal cortices in the medial temporal lobe contribute to certain forms of sensory preconditioning (SPC, a type of higher-order conditioning), we suggest their contributions lie in the encoding and retrieving latently acquired associations, processes which are central to all forms of SPC. We argue this interpretation also captures perirhinal and postrhinal contributions to contextual and episodic memory, hence offering a unifying explanation regarding the contributions of these cortices across multiple paradigms.

animal behavior and cognition↗

bioRxiv2022

NEURONS IN THE POSTRHINAL CORTEX ENCODE NONSPATIAL CONTEXT DURING VISUAL BICONDITIONAL DISCRIMINATION

Spatial context, or the physical surroundings that form the background of an experience, is an essential component of episodic memory. The rodent postrhinal cortex and its primate homolog, the parahippocampal cortex, are thought to preferentially process visuospatial information to represent the spatial features of contexts and scenes. In this study, we addressed open questions about postrhinal function and about how context modulates behavior and cognition. The first question was whether the postrhinal cortex also represents nonspatial contexts. The second question was how representations of context might interact with other cues in the environment. We recorded postrhinal neurons as rats performed a visual nonspatial biconditional discrimination task in which the pattern on the floor determined which object in a pair was correct. Critically, this task design allowed dissociation of location from non-spatial context. We found that postrhinal ensembles and neurons signaled changes in non-spatial context and coded for conjunctions of non-spatial context and objects. Importantly, postrhinal neurons coded for conjunctions of context and objects more often than they coded for conjunctions of location and object. The pattern of findings suggests that postrhinal representations of context may behave like occasion setters by modulating the meaning of other cues in the environment.

neuroscience↗

bioRxiv2021

Social preference in rats not impacted by posterior parietal activity despite overall changes in familiarity-based social behavior

Recent literature points to a potential link between the evolution of complex social behavior and the posterior parietal cortex (PPC) in primates including humans (Parkinson & Wheatley, 2013). Thus far, this theory has been overlooked in other highly social animals that may have also evolved due to social selective pressures. In rodents, there is limited knowledge on the involvement of the PPC on sociality, and most studies of such behavior are limited to understanding social preference. We investigated the role of the PPC through two experiments using the 3-Chamber Sociability and Social Novelty test in rats (Crawley, 2004). In Experiment 1, we used a standard 3-Chamber paradigm, which included two novel demonstrators. In Experiment 2, this paradigm was altered to increase the difference in familiarity between demonstrators such that one demonstrator was highly familiar to the subject and the other was entirely novel. Rats with pre-testing permanent neurotoxic lesions were compared to sham surgery control rats, and the same rats were used for both experiments. Experiments 1 and 2 showed that both groups of rats preferred general social interaction, suggesting no deficit in sociability following PPC damage, regardless of demonstrator identity. Further, experimental and control rats showed similar levels of novelty preference following PPC damage, with novelty preferences increasing in Experiment 2. We argue that heightened novelty preference in Experiment 2 may reflect the increased difference in familiarity between demonstrators. Within the confines of the 3-Chamber task, our results suggest that PPC function was not required for general sociability or social novelty recognition. Because the PPC is implicated in abstract cognition, we argue that existing social tests in rodents may not adequately measure the complex cognitive capacities thought to be supported by the PPC. Future studies should investigate the role of the PPC in social cognition by employing behavioral tasks that require higher cognitive demand rather than testing inherent preference for social partners. Outside of our investigation of the PPC, these results show that social novelty preference can be manipulated through changes in familiarity of demonstrators, and that rats can discriminate others social identities.

animal behavior and cognition↗

bioRxiv2020

Instantaneous amplitude and shape of postrhinal theta oscillations differentially encode running speed

Hippocampal theta oscillations have a temporally asymmetric waveform shape, but it is not known if this theta asymmetry extends to all other cortical regions involved in spatial navigation and memory. Here, using both established and improved cycle-by-cycle analysis methods, we show that theta waveforms in the postrhinal cortex are also temporally asymmetric. On average, the falling phase of postrhinal theta cycles lasts longer than the subsequent rising phase. There are, however, rapid changes in both the instantaneous amplitude and instantaneous temporal asymmetry of postrhinal theta cycles. These rapid changes in amplitude and asymmetry are very poorly correlated, indicative of a mechanistic disconnect between these theta cycle features. We show that the instantaneous amplitude and asymmetry of postrhinal theta cycles differentially encode running speed. Although theta amplitude continues to increase at the fastest running speeds, temporal asymmetry of the theta waveform shape plateaus after medium speeds. Our results suggest that the amplitude and waveform shape of individual postrhinal theta cycles may be governed by partially independent mechanisms and emphasize the importance of employing a single cycle approach to understanding the genesis and behavioral correlates of cortical theta rhythms.

neuroscience↗