Cognitive neuroscience: numerate neurons

Whether the neuronal encoding of number is linear or logarithmic divides cognitive neuroscientists working on mathematical cognition. Recordings from the prefrontal cortex of the monkey support the logarithmic hypothesis. Similarities between number and the coding of other quantities are also beginning to become apparent.     

Cognitive neuroscience: Web alert

A selection of World Wide Web sites relevant to the reviews published in this issue of Current Opinion in Neurobiology.     

Cognitive neuroscience: who to play at poker.

Every neuroscientist knows that emotions are as much to do with the head as the heart, but as a number of new studies show, the heart - or rather the body - and the brain are by no means independent purveyors of feeling and emotion.     

Cognitive neuroscience: early learning centres

Learning leads to neural changes often considered to be driven by 'smart' areas of the brain. A recent study of the cellular changes that underlie perceptual learning has found that plasticity in the primary visual cortex V1 is necessary for learning and the changes that correlate with learning are more complex than one might expect.     

Cognitive neuroscience: acting on numbers

The parietal cortex is a central part of the brain's system for representing numbers and magnitudes. Activity in the parietal cortex might reflect number representation or actions made in response to the numbers.     

Cognitive neuroscience: trickle-down theories of vision

The visual cortex is not a passive recipient of information: predictions about incoming stimuli are made based on experience, partial information and the consequences of inferences. A combination of imaging studies in the human brain has now led to the proposal that the orbitofrontal cortex is a key source of top-down predictions leading to object recognition.     

Nursing behavior: remembrance of things past

Successful suckling is vital to the survival of mammalian newborns. In many mammals, nursing behavior is triggered by maternally derived odors. Such odors may also promote the learned association of odorant cues present in the environment during nursing.     

Cognitive neuroscience: distinguishing self from other

Neurons in medial frontal cortex have been found to distinguish between whether an animal or its partner is responding on a turn-taking task, but are they really the basis of a social learning mechanism?     

Cognitive neuroscience of emotional memory

Emotional events often attain a privileged status in memory. Cognitive neuroscientists have begun to elucidate the psychological and neural mechanisms underlying emotional retention advantages in the human brain. The amygdala is a brain structure that directly mediates aspects of emotional learning and facilitates memory operations in other regions, including the hippocampus and prefrontal cortex. Emotion-memory interactions occur at various stages of information processing, from the initial encoding and consolidation of memory traces to their long-term retrieval. Recent advances are revealing new insights into the reactivation of latent emotional associations and the recollection of personal episodes from the remote past.     

Cognitive neuroscience of creativity: EEG based approaches

Cognitive neuroscience of creativity has been extensively studied using non-invasive electrical recordings from the scalp called electroencephalograms (EEGs) and event related potentials (ERPs). The paper discusses major aspects of performing research using EEG/ERP based experiments including the recording of the signals, removing noise, estimating ERP signals, and signal analysis for better understanding of the neural correlates of processes involved in creativity. Important factors to be kept in mind to record clean EEG signal in creativity research are discussed. The recorded EEG signal can be corrupted by various sources of noise and methodologies to handle the presence of unwanted artifacts and filtering noise are presented followed by methods to estimate ERPs from the EEG signals from multiple trials. The EEG and ERP signals are further analyzed using various techniques including spectral analysis, coherence analysis, and non-linear signal analysis. These analysis techniques provide a way to understand the spatial activations and temporal development of large scale electrical activity in the brain during creative tasks. The use of this methodology will further enhance our understanding the processes neural and cognitive processes involved in creativity.     

Cognitive neuroscience and the law

Advances in cognitive neuroscience now allow us to use physiological techniques to measure and assess mental states under a growing set of circumstances. The implication of this growing ability has not been lost on the western legal community. If biologists can accurately measure mental state, then legal conflicts that turn on the true mental states of individuals might well be resolvable with techniques ranging from electroencephalography to functional magnetic resonance imaging. Therefore, legal practitioners have increasingly sought to employ cognitive neuroscientific methods and data as evidence to influence legal proceedings. This poses a risk, because these scientific methodologies have largely been designed and validated for experimental use only. Their subsequent use in legal proceedings is an application for which they were not intended, and for which those methods are inadequately tested. We propose that neurobiologists, who might inadvertently contribute to this situation, should be aware of how their papers will be read by the legal community and should play a more active role in educating and engaging with that community.     

Cognitive neuroscience: swapping bodies in the brain

A recent study has found that activity in multisensory brain areas, namely the premotor cortex, intraparietal cortex and the putamen, mirrors the vividness of?ownership over a mannequin, induced by the body-swap illusion.     

Cognitive neuroscience: feedback for natural visual stimuli

Recurrent signals in the brain are often associated with slower sensory and cognitive processes. Such patterns of activity may also form the basis of rapid perception.     

Cognitive neuroscience: scene layout from vision and touch

Parahippocampal and retrosplenial cortices respond strongly to visual scenes. A new study shows that these regions also activate when scenes are perceived haptically - even in the blind.     

Cognitive neuroscience: vision and touch are constant companions

To act on objects in the world around us, we must first construct an accurate representation of where they are physically located. Recent investigations have begun to shed light on how the brain dynamically binds together visual and somatosensory signals to create task-dependent representations that maintain object constancy.     

Cognitive neuroscience: searching for the bottleneck in the brain

People simply cannot do two things at once, as shown by research on the so-called psychological refractory period. A new neuroimaging study has now localized the response-selection bottleneck underlying the psychological refractory period to a frontoparietal network.     

Remembrance of things past: maintaining gene expression patterns with altered chromatin

Eukaryotic organisms have evolved mechanisms to stably preserve the gene expression patterns that determine cell fate. Recent advances have been made in understanding the DNA sequences and protein factors required to propagate gene activation or silencing. These studies suggest that, after gene activity states are selected during development, maintenance protein complexes provide a molecular memory of those states by altering a local domain of chromatin structure.