Journal of Neuroscience

The hierarchically organized structures of the medial temporal lobe are critically important for episodic memory function. Accumulating evidence suggests dissociable information processing pathways are maintained throughout these structures including in the medial and lateral entorhinal cortex. Cortical layers provide an additional dimension of dissociation as the primary input to the hippocampus derives from layer-2 neurons in the entorhinal cortex while the deeper layers primarily receive output from the hippocampus...

Mirror-image pain arises from pathological alterations in the nociceptive processing network that controls functional lateralization of the primary afferent input. Although a number of clinical syndromes related to dysfunction of the lumbar afferent system are associated with the mirror-image pain, its morphophysiological substrate and mechanism of induction remain poorly understood. Therefore, we used ex-vivo spinal cord preparation of young rats of both sexes to study organization and processing of the contralateral afferent input to the neurons in the major spinal nociceptive projection area lamina I...

Action potential-independent (miniature) neurotransmission occurs at all chemical synapses, but remains poorly understood, particularly in pathological contexts. Axonal endoplasmic reticulum (ER) Ca2+ stores are thought to influence miniature neurotransmission, and aberrant ER Ca2+ handling is implicated in progression of Huntington disease (HD). Here, we report elevated miniature excitatory postsynaptic current (mEPSC) frequencies in recordings from YAC128 mouse (HD-model) neurons (from cortical cultures and striatum-containing brain slices - both from male and female animals)...

In everyday life, we integrate visual and auditory information in routine tasks such as navigation and communication. While concurrent sound can improve visual perception, the neuronal correlates of audiovisual integration are not fully understood. Specifically, it remains unclear whether neuronal firing patters in the primary visual cortex (V1) of awake animals demonstrate similar sound-induced improvement in visual discriminability. Furthermore, presentation of sound is associated with movement in the subjects, but little is understood about whether and how sound-associated movement affects audiovisual integration in V1...

Working memory enables the temporary storage of relevant information in the service of behavior. Neuroimaging studies have suggested that sensory cortex is involved in maintaining contents in working memory. This raised the question of how sensory regions maintain memory representations during the exposure to distracting stimuli. Multivariate pattern analysis of functional magnetic resonance imaging (fMRI) signals in visual cortex has shown that the contents of visual working memory could be decoded concurrently with passively viewed distractors...

From moment to moment, the visual properties of objects in the world fluctuate due to external factors like ambient lighting, occlusion and eye movements, and internal (proximal) noise. Despite this variability in the incoming information, our perception is stable. Serial dependence, the behavioral attraction of current perceptual responses towards previously seen stimuli, may reveal a mechanism underlying stability: a spatio-temporally tuned operator that smoothes over spurious fluctuations. The current study examined the neural underpinnings of serial dependence by recording the electroencephalographic (EEG) brain response of female and male human observers to prototypical objects (faces, cars and houses) and morphs that mixed properties of two prototypes...

Neocortical Layer 1 (L1) consists of the distal dendrites of pyramidal cells and GABAergic interneurons (INs) and receives extensive long-range "top-down" projections, but L1 INs remain poorly understood. In this work, we systematically examined the distinct dominant electrophysiological features for four unique IN subtypes in L1 that were previously identified from mice of either gender: Canopy cells show an irregular firing pattern near rheobase; Neurogliaform cells (NGFCs) are late-spiking, and their firing rate accelerates during current injections; cells with strong expression of the α 7 nicotinic receptor ( α 7 cells), display onset (rebound) bursting; vasoactive intestinal peptide (VIP) expressing cells exhibit high input resistance, strong adaptation, and irregular firing...

Alternative splicing of AMPA-type glutamate receptors (AMPARs) and allosteric modulation by auxiliary subunits, such as transmembrane AMPAR regulatory proteins (TARPs), are two important mechanisms that regulate the time course of glutamatergic neurotransmission. Prior work has shown that alternative splicing of the flip/flop cassette profoundly regulates TARP γ2 modulation, where flip receptor gating exhibits robust sensitivity to TARPs while flop isoforms are relatively insensitive to TARP modulation...

During early development memory systems gradually mature over time, in parallel with the gradual accumulation of knowledge. Yet, it is unknown whether and to what extent maturation is driven by discrete experience. Sleep is thought to contribute to the formation of long-term memory and knowledge through a systems consolidation process that is driven by specific sleep oscillations, i.e., ripples, spindles, and slow oscillations (SOs), in cortical and hippocampal networks. Based on these oscillatory signatures, we show here in rats that discrete spatial experience speeds the functional maturation of spatial memory systems during development...

Both passive tactile stimulation and motor actions result in dynamic changes in beta band (15-30 Hz Hz) oscillations over somatosensory cortex. Similar to alpha band (8-12 Hz) power decrease in the visual system, beta band power also decreases following stimulation of the somatosensory system. This relative suppression of α and β oscillations is generally interpreted as an increase in cortical excitability. Here, next to traditional single-pulse stimuli, we employed a random intensity continuous right index finger tactile stimulation (white noise), which enabled us to uncover an impulse response function (IRF) of the somatosensory system...

Transcription factors have a pivotal role in synaptic plasticity and the associated modification of neuronal networks required for memory formation and consolidation. The nuclear receptors subfamily 4 group A (Nr4a) have emerged as possible modulators of hippocampal synaptic plasticity and cognitive functions. However, the molecular and cellular mechanisms underlying Nr4a2-mediated hippocampal synaptic plasticity are not completely known. Here, we report that neuronal activity enhances Nr4a2 expression and function in cultured mouse hippocampal neurons (both sexes) by an ionotropic glutamate receptor/Ca2+ /cAMP response element-binding protein/CREB-regulated transcription factor 1 (iGluR/Ca2+ /CREB/CRTC1) pathway...

Human learning and decision making is supported by multiple systems operating in parallel. Recent studies isolating the contributions of reinforcement learning (RL) and working memory (WM) have revealed a trade-off between the two. An interactive WM-RL computational model predicts that while high WM load slows behavioral acquisition, it also induces larger prediction errors in the RL system that enhance robustness and retention of learned behaviors. Here we tested this account by parametrically manipulating WM load during RL in conjunction with EEG, in both male and female participants, and administered two surprise memory tests...

Antidepressants, while effective in treating depression and anxiety disorders, also induce deficits in sensory (particularly auditory) processing, which in turn may exacerbate psychiatric symptoms. How antidepressants cause auditory signature deficits remains largely unknown. Here, we found that fluoxetine-treated adult female rats were significantly less accurate when performing a tone-frequency discrimination task compared with age-matched control rats. Their cortical neurons also responded less selectively to sound frequencies...

Acquisition of a behavioural task is influenced by many factors. The relative timing of stimuli is such a factor and is especially relevant for tasks relying on short-term memory, like working memory paradigms, due to the constant evolution and decay of neuronal activity evoked by stimuli. Here we assess two aspects of stimulus timing on the acquisition of an olfactory delayed non-match-to-sample (DNMS) task. We demonstrate that head-fixed male mice learn to perform the task more quickly when the initial training uses a shorter sample-test odour delay without detectable loss of generalisability...

This study examined the effect of danger on consolidation of neutral information in two regions of the rat (male and female) medial temporal lobe: the perirhinal cortex (PRh) and basolateral amygdala complex (BLA). The neutral information was the association that forms between an auditory stimulus and a visual stimulus (labelled S2 and S1) across their pairings in sensory preconditioning. We show that, when the sensory preconditioning session is followed by a shocked context exposure, the danger shifts consolidation of the S2-S1 association from the PRh to the BLA; and does so by interacting with processes involved in encoding of the S2-S1 pairings...

In the human brain, aversive and appetitive processing have been studied with controlled stimuli in rather static settings. In addition, the extent to which aversive- and appetitive-related processing engage distinct or overlapping circuits remains poorly understood. Here, we sought to investigate the dynamics of aversive and appetitive processing while male and female participants engaged in comparable trials involving threat-avoidance or reward-seeking. A central goal was to characterize the temporal evolution of responses during periods of threat or reward imminence For example, in the aversive domain, we predicted that the bed nucleus of the stria terminalis (BST), but not the amygdala, would exhibit anticipatory responses given the role of the former in anxious apprehension...

The purpose of our study was to identify the low-dimensional latent components, defined hereafter as motor unit modes , underlying the discharge rates of the motor units in two knee extensors (vastus medialis and lateralis, eight men) and two hand muscles (first dorsal interossei and thenars, seven men and one woman) during submaximal isometric contractions. Factor analysis identified two independent motor unit modes that captured most of the covariance of the motor unit discharge rates. We found divergent distributions of the motor unit modes for the hand and vastii muscles...

The organizational principles of the object space represented in the human ventral visual cortex are debated. Here we contrast two prominent proposals that, in addition to an organization in terms of animacy, propose either a representation related to aspect ratio (stubby-spiky) or to the distinction between faces and bodies. We designed a critical test that dissociates the latter two categories from aspect ratio and investigated responses from human fMRI (of either sex) and deep neural networks (BigBiGAN)...

Numerosity, the set size of a group of items, helps guide human and animals' behavior and decisions. Numerosity perception is thought to be a precursor of symbolic numerical cognition. Previously, we uncovered neural populations selectively tuned to numerosities organized in a network of topographic maps in human association cortex. Here we investigate whether these numerosity maps are also involved in the processing of symbolic numbers, using 7T fMRI and a number-detection task. We recruited seven participants (three females) and found that the numerosity map at the temporal-occipital cortex (NTO) also respond to symbolic numbers...

The ability to extract rhythmic structure is important for the development of language, music and social communication. Although previous studies show infants' brains entrain to the periodicities of auditory rhythms and even different metrical interpretations (e.g., groups of two vs. three beats) of ambiguous rhythms, whether the premature brain tracks beat and meter frequencies had not been explored previously. We used high-resolution electroencephalography, while premature infants (n = 19, five male, mean age 32 ± 2...