Global timing: a conceptual framework to investigate the neural basis of rhythm perception in humans and non-human species

Timing cues are an essential feature of music. To understand how the brain gives rise to our experience of music we must appreciate how acoustical temporal patterns are integrated over the range of several seconds in order to extract global timing. In music perception, global timing comprises three distinct but often interacting percepts: temporal grouping, beat, and tempo. What directions may we take to further elucidate where and how the global timing of music is processed in the brain? The present perspective addresses this question and describes our current understanding of the neural basis of global timing perception

Aspirations, adaptive learning and cooperation in repeated games

Game Theory;Repeated Games

Neuronal Mechanisms and Transformations Encoding Time-Varying Signals

Sensation in natural environments requires the analysis of time-varying signals. While previous work has uncovered how a signal’s temporal rate is represented by neurons in sensory cortex, in this issue of Neuron, new evidence from Gao et al. (2016) provides insights on the underlying mechanisms

Flies Sleep on It, or Fuhgeddaboudit!

Many studies in diverse organisms, including humans, have demonstrated a fundamental role for sleep in the formation of memories. A new study by Berry et al. indicates that, in fruit flies, sleep accomplishes this in part by preventing an active process of forgetting

Does the Hippocampus Map Out the Future?

Decades of research have established two central roles of the hippocampus - memory consolidation and spatial navigation. Recently, a third function of the hippocampus has been proposed: simulating future events. However, claims that the neural patterns underlying simulation occur without prior experience have come under fire in light of newly published data

How Targeted Memory Reactivation Promotes the Selective Strengthening of Memories in Sleep

Over the last ten years, scientists have developed a method called targeted memory reactivation (TMR) for selectively strengthening memories during sleep. Prior to this, memory manipulation during sleep was at most a plot device in science fiction movies, but a large corpus of studies now demonstrates that TMR is both reliable and effective. TMR studies hypothesize that this method taps into normal consolidation mechanisms that require the repeated replay of memories during sleep. This idea has recently been supported by several new studies demonstrating that TMR upregulates the reactivation of cued memories, and that such upregulation predicts subsequent memory performance. This new body of work provides a unique window onto many properties of memory reactivation and helps to close the gap between our understanding of replay in rodents, where it has been visualised at the neural level for many years, and humans, where such studies are only just starting to become possible. We will discuss this new literature and highlight the vast potential of these new methods for future research

The role of adaptation in generating monotonic rate codes in auditory cortex

In primary auditory cortex, slowly repeated acoustic events are represented temporally by the stimulus-locked activity of single neurons. Single-unit studies in awake marmosets (Callithrix jacchus) have shown that a sub-population of these neurons also monotonically increase or decrease their average discharge rate during stimulus presentation for higher repetition rates. Building on a computational single-neuron model that generates stimulus-locked responses with stimulus evoked excitation followed by strong inhibition, we find that stimulus-evoked short-term depression is sufficient to produce synchronized monotonic positive and negative responses to slowly repeated stimuli. By exploring model robustness and comparing it to other models for adaptation to such stimuli, we conclude that short-term depression best explains our observations in single-unit recordings in awake marmosets. Together, our results show how a simple biophysical mechanism in single neurons can generate complementary neural codes for acoustic stimuli

The role of inhibition in a computational model of an auditory cortical neuron during the encoding of temporal information.

In auditory cortex, temporal information within a sound is represented by two complementary neural codes: a temporal representation based on stimulus-locked firing and a rate representation, where discharge rate co-varies with the timing between acoustic events but lacks a stimulus-synchronized response. Using a computational neuronal model, we find that stimulus-locked responses are generated when sound-evoked excitation is combined with strong, delayed inhibition. In contrast to this, a non-synchronized rate representation is generated when the net excitation evoked by the sound is weak, which occurs when excitation is coincident and balanced with inhibition. Using single-unit recordings from awake marmosets (Callithrix jacchus), we validate several model predictions, including differences in the temporal fidelity, discharge rates and temporal dynamics of stimulus-evoked responses between neurons with rate and temporal representations. Together these data suggest that feedforward inhibition provides a parsimonious explanation of the neural coding dichotomy observed in auditory cortex

Enhance, delete, incept: Manipulating hippocampus-dependent memories.

Here we provide a brief overview of recent research on memory manipulation. We focus primarily on memories for which the hippocampus is thought to be required due to its central importance in the study of memory. The repertoire of methods employed is expanding and includes optogenetics, transcranial stimulation, deep brain stimulation, cued reactivation during sleep and the use of pharmacological agents. In addition, the possible mechanisms underlying these memory changes have been investigated using techniques such as single unit recording and functional magnetic resonance imaging (fMRI). This article is part of a Special Issue entitled 'Memory enhancement'