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Neuroscience and Biobehavioral Reviews Nov 2018What any sensory neuron knows about the world is one of the cardinal questions in Neuroscience. Information from the sensory periphery travels across synaptically... (Review)
Review
What any sensory neuron knows about the world is one of the cardinal questions in Neuroscience. Information from the sensory periphery travels across synaptically coupled neurons as each neuron encodes information by varying the rate and timing of its action potentials (spikes). Spatiotemporally correlated changes in this spiking regimen across neuronal populations are the neural basis of sensory representations. In the somatosensory cortex, however, spiking of individual (or pairs of) cortical neurons is only minimally informative about the world. Recent studies showed that one solution neurons implement to counteract this information loss is adapting their rate of information transfer to the ongoing synaptic activity by changing the membrane potential at which spike is generated. Here we first introduce the principles of information flow from the sensory periphery to the primary sensory cortex in a model sensory (whisker) system, and subsequently discuss how the adaptive spike threshold gates the intracellular information transfer from the somatic post-synaptic potential to action potentials, controlling the information content of communication across somatosensory cortical neurons.
Topics: Action Potentials; Animals; Cell Communication; Information Theory; Neurons; Perception; Somatosensory Cortex; Vibrissae
PubMed: 30227142
DOI: 10.1016/j.neubiorev.2018.09.007 -
Revista Brasileira de Psiquiatria (Sao... 2019Since the pioneering work of Penfield and his colleagues in the 1930s, the somatosensory cortex, which is located on the postcentral gyrus, has been known for its... (Review)
Review
Since the pioneering work of Penfield and his colleagues in the 1930s, the somatosensory cortex, which is located on the postcentral gyrus, has been known for its central role in processing sensory information from various parts of the body. More recently, a converging body of literature has shown that the somatosensory cortex also plays an important role in each stage of emotional processing, including identification of emotional significance in a stimulus, generation of emotional states, and regulation of emotion. Importantly, studies conducted in individuals suffering from mental disorders associated with abnormal emotional regulation, such as major depression, bipolar disorder, schizophrenia, post-traumatic stress disorder, anxiety and panic disorders, specific phobia, obesity, and obsessive-compulsive disorder, have found structural and functional changes in the somatosensory cortex. Common observations in the somatosensory cortices of individuals with mood disorders include alterations in gray matter volume, cortical thickness, abnormal functional connectivity with other brain regions, and changes in metabolic rates. These findings support the hypothesis that the somatosensory cortex may be a treatment target for certain mental disorders. In this review, we discuss the anatomy, connectivity, and functions of the somatosensory cortex, with a focus on its role in emotional regulation.
Topics: Emotions; Humans; Magnetic Resonance Imaging; Mental Disorders; Somatosensory Cortex
PubMed: 30540029
DOI: 10.1590/1516-4446-2018-0183 -
Current Opinion in Neurobiology Aug 2009
Topics: Animals; Humans; Neural Pathways; Sensation; Somatosensory Cortex
PubMed: 19717297
DOI: 10.1016/j.conb.2009.08.002 -
Journal of Neurophysiology Feb 2015The goal of this review is to start to consolidate and distill the substantial body of research that comprises the published work of the late Professor Steven S. Hsiao.... (Review)
Review
The goal of this review is to start to consolidate and distill the substantial body of research that comprises the published work of the late Professor Steven S. Hsiao. The studies of Hsiao began by demonstrating the receptive field properties of somatosensory neurons, progressed to describing cortical feature selectivity, and then eventually elevated the field to hopes of tapping into natural neural codes with artificial somatosensory feedback. With ongoing analogies to contemporaneous studies in visual neuroscience, the research results and writings of Hsiao have provided the fields of haptics and somatosensory neurophysiology with the conceptual tools needed to allow profound progress. Specifically, Hsiao suggested that slowly adapting tactile form perception could be restored with cortical microstimulation, rapidly adapting slip reflexes should be relegated to low-level, hard-wired prosthetic components, and Pacinian-corpuscle spatiotemporal population responses could potentially be decoded/encoded to provide information about interactions of hands and hand-held instruments with external objects. Future studies will be guided by these insightful reports from Hsiao.
Topics: Animals; Evoked Potentials, Somatosensory; Humans; Somatosensory Cortex; Touch Perception
PubMed: 25392173
DOI: 10.1152/jn.00670.2014 -
Cell and Tissue Research Jan 2019Motherhood in mammals involves tremendous changes throughout the body and central nervous system, which support attention and nurturing of infants. Maternal care... (Review)
Review
Motherhood in mammals involves tremendous changes throughout the body and central nervous system, which support attention and nurturing of infants. Maternal care consists of complex behaviors, such as nursing and protection of the offspring, requiring new mothers to become highly sensitive to infant needs. Long-lasting neural plasticity in various regions of the cerebral cortex may enable the perception and recognition of infant cues, important for appropriate caregiving responses. Recent findings have demonstrated that the neuropeptide oxytocin is involved in a number of physiological processes, including parturition and lactation and dynamically shaping neuronal responses to infant stimuli as well. Here, we review experience-dependent changes within the cortex occurring throughout motherhood, focusing on plasticity of the somatosensory and auditory cortex. We outline the role of oxytocin in gating cortical plasticity and discuss potential mechanisms regulating oxytocin release in response to different sensory stimuli.
Topics: Animals; Nerve Net; Neuronal Plasticity; Neurotransmitter Agents; Oxytocin; Signal Transduction; Somatosensory Cortex
PubMed: 30062614
DOI: 10.1007/s00441-018-2883-1 -
Annals of the New York Academy of... Apr 2011The somatosensory cortex of many rodents, lagomorphs, and marsupials contains distinct cytoarchitectonic features named "barrels" that reflect the pattern of large... (Review)
Review
The somatosensory cortex of many rodents, lagomorphs, and marsupials contains distinct cytoarchitectonic features named "barrels" that reflect the pattern of large facial whiskers on the snout. Barrels are composed of clustered thalamocortical afferents relaying sensory information from one whisker surrounded by cell-dense walls or "barrels" in layer 4 of the cortex. In many ways, barrels are a simple and relatively accessible canonical cortical column, making them a common model system for the examination of cortical development and function. Despite their experimental accessibility and popularity, we still lack a basic understanding of how and why barrels form in the first place. In this review, we will examine what is known about mechanisms of barrel development, focusing specifically on the recent literature using the molecular-genetic power of mice as a model system for examining brain development.
Topics: Animals; Body Patterning; Hair Follicle; Mice; Models, Biological; Organ Specificity; Somatosensory Cortex; Vibrissae
PubMed: 21534999
DOI: 10.1111/j.1749-6632.2011.06024.x -
Advanced Science (Weinheim,... May 2022Head direction (HD) cells form a fundamental component in the brain's spatial navigation system and are intricately linked to spatial memory and cognition. Although HD...
Head direction (HD) cells form a fundamental component in the brain's spatial navigation system and are intricately linked to spatial memory and cognition. Although HD cells have been shown to act as an internal neuronal compass in various cortical and subcortical regions, the neural substrate of HD cells is incompletely understood. It is reported that HD cells in the somatosensory cortex comprise regular-spiking (RS, putative excitatory) and fast-spiking (FS, putative inhibitory) neurons. Surprisingly, somatosensory FS HD cells fire in bursts and display much sharper head-directionality than RS HD cells. These FS HD cells are nonconjunctive, rarely theta rhythmic, sparsely connected and enriched in layer 5. Moreover, sharply tuned FS HD cells, in contrast with RS HD cells, maintain stable tuning in darkness; FS HD cells' coexistence with RS HD cells and angular head velocity (AHV) cells in a layer-specific fashion through the somatosensory cortex presents a previously unreported configuration of spatial representation in the neocortex. Together, these findings challenge the notion that FS interneurons are weakly tuned to sensory stimuli, and offer a local circuit organization relevant to the generation and transmission of HD signaling in the brain.
Topics: Interneurons; Neurons; Somatosensory Cortex; Spatial Navigation
PubMed: 35297541
DOI: 10.1002/advs.202200020 -
Proceedings of the National Academy of... Dec 2020Seasonal cycles govern life on earth, from setting the time for the mating season to influencing migrations and governing physiological conditions like hibernation. The...
Seasonal cycles govern life on earth, from setting the time for the mating season to influencing migrations and governing physiological conditions like hibernation. The effect of such changing conditions on behavior is well-appreciated, but their impact on the brain remains virtually unknown. We investigate long-term seasonal changes in the mammalian brain, known as Dehnel's effect, where animals exhibit plasticity in body and brain sizes to counter metabolic demands in winter. We find large seasonal variation in cellular architecture and neuronal activity in the smallest terrestrial mammal, the Etruscan shrew, Their brain, and specifically their neocortex, shrinks in winter. Shrews are tactile hunters, and information from whiskers first reaches the somatosensory cortex layer 4, which exhibits a reduced width (-28%) in winter. Layer 4 width (+29%) and neuron number (+42%) increase the following summer. Activity patterns in the somatosensory cortex show a prominent reduction of touch-suppressed neurons in layer 4 (-55%), the most metabolically active layer. Loss of inhibitory gating occurs with a reduction in parvalbumin-positive interneurons, one of the most active neuronal subtypes and the main regulators of inhibition in layer 4. Thus, a reduction in neurons in layer 4 and particularly parvalbumin-positive interneurons may incur direct metabolic benefits. However, changes in cortical balance can also affect the threshold for detecting sensory stimuli and impact prey choice, as observed in wild shrews. Thus, seasonal neural adaptation can offer synergistic metabolic and behavioral benefits to the organism and offer insights on how neural systems show adaptive plasticity in response to ecological demands.
Topics: Animals; Energy Metabolism; Female; Hibernation; Magnetic Resonance Imaging; Male; Neuronal Plasticity; Neurons; Organ Size; Seasons; Shrews; Somatosensory Cortex; Touch Perception; Vibrissae
PubMed: 33257560
DOI: 10.1073/pnas.1922888117 -
Clinical Neurophysiology : Official... Jul 2021We assessed in extremely preterm born (EPB) children whether secondary somatosensory cortex (SII) responses recorded with magnetoencephalography (MEG) at term-equivalent...
OBJECTIVE
We assessed in extremely preterm born (EPB) children whether secondary somatosensory cortex (SII) responses recorded with magnetoencephalography (MEG) at term-equivalent age (TEA) correlate with neurodevelopmental outcome at age 6 years. Secondly, we assessed whether SII responses differ between 6-year-old EPB and term-born (TB) children.
METHODS
39 EPB children underwent MEG with tactile stimulation at TEA. At age 6 years, 32 EPB and 26 TB children underwent MEG including a sensorimotor task requiring attention and motor inhibition. SII responses to tactile stimulation were modeled with equivalent current dipoles. Neurological outcome, motor competence, and general cognitive ability were prospectively evaluated at age 6 years.
RESULTS
Unilaterally absent SII response at TEA was associated with abnormal motor competence in 6-year-old EPB children (p = 0.03). At age 6 years, SII responses were bilaterally detectable in most EPB (88%) and TB (92%) children (group comparison, p = 0.69). Motor inhibition was associated with decreased SII peak latencies in TB children, but EPB children lacked this effect (p = 0.02).
CONCLUSIONS
Unilateral absence of an SII response at TEA predicted poorer motor outcome in EPB children.
SIGNIFICANCE
Neurophysiological methods may provide new means for outcome prognostication in EPB children.
Topics: Child; Cohort Studies; Developmental Disabilities; Evoked Potentials, Somatosensory; Female; Humans; Infant, Extremely Premature; Infant, Newborn; Magnetic Resonance Imaging; Magnetoencephalography; Male; Somatosensory Cortex
PubMed: 34023633
DOI: 10.1016/j.clinph.2021.04.005 -
Journal of Neurophysiology Sep 2020Rodents and other mammals acquire sensory information by precisely orchestrated head, whisker, and respiratory movements. We have, however, only limited information... (Comparative Study)
Comparative Study
Rodents and other mammals acquire sensory information by precisely orchestrated head, whisker, and respiratory movements. We have, however, only limited information about integration of these signals. In the somatosensory domain, the integration of somatosensory information with other modalities is particularly pertinent for body parts such as eyes, ears, and nose, which serve another modality. Here we analyzed the nose/nostril representation in the rodent somatosensory cortex. We identified the representation of the nose/nostril in the rat somatosensory cortex by receptive field mapping and subsequent histological reconstruction. In tangential somatosensory cortical sections, the rat nostril cortex was evident as a prominent stripe-like recess of layer 4 revealed by cytochrome- oxidase reactivity or by antibodies against the vesicular glutamate-transporter-2 (identifying thalamic afferents). We compared flattened somatosensory cortices of various rodents including rats, mice, gerbils, chinchillas, and chipmunks. We found that such a nose/nostril module was evident as a region with thinned or absent layer 4 at the expected somatotopic position of the nostril. Extracellular spike activity was strongly modulated by respiration in the rat somatosensory cortex, and field potential recordings revealed a stronger locking of nostril recording sites to respiration than for whisker/barrel cortex recoding sites. We conclude that the rodent nose/nostril representation has a conserved architecture and specifically interfaces with respiration signals. We characterized the rodent nose somatosensory cortex. The nostril representation appeared as a kind of "hole" (i.e., as a stripe-like recess of layer 4) in tangential cortical sections. Neural activity in nose somatosensory cortex was locked to respiration, and simultaneous field recordings indicate that this locking was specific to this region. Our results reveal previously unknown cytoarchitectonic and physiological properties of the rodent nose somatosensory cortex, potentially enabling it to integrate multiple sensory modalities.
Topics: Animals; Chinchilla; Electrophysiological Phenomena; Gerbillinae; Male; Mice; Mice, Inbred C57BL; Nose; Rats; Rats, Long-Evans; Respiration; Rodentia; Sciuridae; Somatosensory Cortex
PubMed: 32783591
DOI: 10.1152/jn.00138.2020