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The ability to detect rare auditory events can be critical for survival. We report here that neurons in cat primary auditory cortex (A1) responded more strongly to a rarely presented sound than to the same sound when it was common. For the rare stimuli, we used both frequency and amplitude deviants. Moreover, some A1 neurons showed hyperacuity for frequency(More)
Neurons in primary auditory cortex (A1) of cats show strong stimulus-specific adaptation (SSA). In probabilistic settings, in which one stimulus is common and another is rare, responses to common sounds adapt more strongly than responses to rare sounds. This SSA could be a correlate of auditory sensory memory at the level of single A1 neurons. Here we(More)
Grid cells provide a neural representation of space, by discharging when an animal traverses through the vertices of a periodic hexagonal grid spanning the environment. Although grid cells have been characterized in detail in rats, the fundamental question of what neural dynamics give rise to the grid structure remains unresolved. Two competing classes of(More)
Many animals, on air, water, or land, navigate in three-dimensional (3D) environments, yet it remains unclear how brain circuits encode the animal's 3D position. We recorded single neurons in freely flying bats, using a wireless neural-telemetry system, and studied how hippocampal place cells encode 3D volumetric space during flight. Individual place cells(More)
The sonar systems of bats and dolphins are in many ways superior to man-made sonar and radar systems, and considerable effort has been devoted to understanding the signal-processing strategies underlying these capabilities. A major feature determining the efficiency of sonar systems is the sensitivity to noise and jamming signals. Previous studies indicated(More)
The "place fields" of hippocampal pyramidal neurons are not static. For example, upon a contextual change in the environment, place fields may "remap" within typical timescales of ~ 1 min. A few studies have shown more rapid dynamics in hippocampal activity, linked to internal processes, such as switches between spatial reference frames or changes within(More)
Neurons in sensory cortices are often assumed to be "feature detectors", computing simple and then successively more complex features out of the incoming sensory stream. These features are somehow integrated into percepts. Despite many years of research, a convincing candidate for such a feature in primary auditory cortex has not been found. We argue that(More)
The hippocampus is crucial for episodic and spatial memory. In freely moving rodents, hippocampal pyramidal neurons show spatially selective firing when the animal passes through a neuron's 'place-field', and theta-band oscillation is continuously present during locomotion. Here we report the first hippocampal recordings from echolocating bats, mammals(More)
For over half a century, the echolocating bat has served as a valuable model in neuroscience to elucidate mechanisms of auditory processing and adaptive behavior in biological sonar. Our article emphasizes the importance of the bat's vocal-motor system to spatial orientation by sonar, and we present this view in the context of three problems that the(More)
Animals using active sensing systems such as echolocation or electrolocation may experience interference from the signals of neighbouring conspecifics, which can be offset by a jamming avoidance response (JAR). Here, we report JAR in one echolocating bat (Tadarida teniotis: Molossidae) but not in another (Taphozous perforatus: Emballonuridae) when both flew(More)