Does the preoptic anterior hypothalamus receive thermoafferent information?

1998 ◽  
Vol 274 (1) ◽  
pp. R9-R18 ◽  
Author(s):  
Nancy J. Berner ◽  
H. Craig Heller
Keyword(s):  
Brain Regions ◽  
Anterior Hypothalamus ◽  
Mammalian Brain ◽  
Eeg Activity ◽  
Arousal State ◽  
Firing Rates ◽  
State Changes ◽  
Unanesthetized Animals ◽  
Peripheral Temperature ◽  
State Selectivity

The preoptic anterior hypothalamus (POAH) is considered the thermointegrative center of the mammalian brain. Studies on anesthetized and unanesthetized animals have demonstrated neurons in the POAH that respond to changes in both POAH temperature (TPOAH) and skin temperature (Ts). In these studies, however, electroencephalographic (EEG) activity was not monitored. Recent work has revealed the potential for arousal state selectivity of neurons combined with thermal influences on arousal state to create the appearance that cells are thermosensitive or thermoresponsive when in fact they may not be responding directly to temperature or to thermoafferent input. It is therefore necessary to reexamine the influence of central and peripheral temperature on POAH cells. In the present study, 66 POAH cells were recorded from urethan-anesthetized rats while EEG, TPOAH, and Ts were monitored. Seventy-five percent (41 of 55) of the cells were EEG state responsive; 22% (6 of 27) were TPOAH sensitive; and 33% (19 of 58) appeared to be Tsresponsive. However, when EEG state changes were taken into account, none of the cells that appeared to be Ts responsive were responding to Ts within any uniform EEG state. All changes in their firing rates were associated with EEG state changes. This study raises a question as to whether or not peripheral temperature information is integrated in the POAH. Consideration should be given to the possibility that Ts information is integrated lower in the neuroaxis. Monitoring EEG is essential in studies attempting to characterize the integrative properties of POAH neurons of anesthetized or unanesthetized animals. This caveat applies not just to thermoregulatory studies but to investigations of other integrative functions of the hypothalamus and many other brain regions as well.

Arousal state vs. temperature effects on neuronal activity in subcoeruleus area

1989 ◽  
Vol 256 (4) ◽  
pp. R840-R849 ◽  
Author(s):  
D. A. Grahn ◽  
C. M. Radeke ◽  
H. C. Heller
Keyword(s):  
Unit Activity ◽  
Single Unit ◽  
Single Unit Activity ◽  
Transient Responses ◽  
Eeg Activity ◽  
Arousal State ◽  
Firing Rates ◽  
Primary Determinant ◽  
Thermal Stimuli ◽  
Eeg Pattern

It is believed that thermoafferent neurons synapse in the subcoeruleus area (SC). To assess the effect of arousal state on thermoafferent information processing, we recorded SC unit activity in unanesthetized rats. No responses to changes in ambient temperature were observed within an arousal state, but 85% of the units dramatically altered their firing rates as the arousal state changed. We replicated previous experiments on anesthetized animals which were the basis for ascribing thermoafferent function to the SC. Additionally, we monitored electroencephalographic (EEG) activity. In lightly anesthetized rats, five distinct EEG states could be defined, and the temperature profile of the animal was a primary determinant of the EEG state. No thermoresponses were observed within an EEG state, but 78% of the units dramatically altered their firing rates in synchrony with EEG pattern changes. Transient responses to noxious stimuli were also reflected in both the EEG patterns and single-unit activity. We conclude that SC single-unit activity is not specific for processing of thermal information but is correlated with EEG activity, which in turn is determined by a variety of factors including thermal stimuli.

Cortical long-axoned cells and putative interneurons during the sleep-waking cycle

1978 ◽  
Vol 1 (3) ◽  
pp. 465-485 ◽  
Author(s):  
Mircea Steriade
Keyword(s):  
High Frequency ◽  
Mammalian Brain ◽  
Sleep Stages ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Eeg Activity ◽  
Firing Rates ◽  
Waking And Sleep ◽  
Cortical Interneurons

AbstractKnowledge of the input-output characteristics of various neuronal types is a necessary first step toward an understanding of cellular events related to waking and sleep. In spite of the oversimplification involved, the dichotomy in terms of type I (long-axoned, output) neurons and type II (short-axoned, local) interneurons is helpful in functionally delineating the neuronal circuits involved in the genesis and epiphenomena of waking and sleep states. The possibility is envisaged that cortical interneurons, which are particularly related to higher neuronal activity and have been found in previous experiments to be more active during sleep than during wakefulness, might be involved in complex integrative processes occurring during certain sleep stages. Electrophysiological criteria for the identification of output cells and interneurons are developed, with emphasis on various possibilities and difficulties involved in recognizing interneurons of the mammalian brain. The high-frequency repetitive activity of interneurons is discussed, together with various possibilities of error to be avoided when interpreting data from bursting cells. Data first show opposite changes in spontaneous and evoked discharges of identified output cells versus putative interneurons recorded from motor and parietal association cortical areas in behaving monkeys and cats during wakefulness (W) compared to sleep with synchronized EEG activity (S): significantly increased rates of spontaneous firing, enhanced antidromic or synaptic responsiveness, associated with shorter periods of inhibition in type I (pyramidal tract, cortico-thalamic and cortico-pontine) cells during W versus significantly decreased frequencies of spontaneous discharge and depression of synaptically elicited reponses of type II cells during W compared to S. These findings are partly explained on the basis of recent iontophoretic studies showing that acetylcholine, viewed as a synaptic transmitter of the arousal system, excites output-type neurons and inhibits high-frequency bursting cells. Comparing W and S to the deepest stage of sleep with desynchronized EEG activity (D) in type I and type II cells revealed that: (a) the increased firing rates of output cells in D, over those in W and S, is substantially due to a tonic excitation during this state, and rapid eye movements (REMs) only contribute to the further increase of discharge frequencies; (b) in contrast, the increased rates of discharge in interneurons during D is entirely ascribable to REM-related firing. On the basis of experiments reporting that increased duration of D has beneficial effects upon retention of information acquired during W, the suggestion is made that increased firing rates of association cortical interneurons during REM epochs of D sleep are an important factor in maintaining the soundness of a memory trace.

scholarly journals An architectonic type principle in the development of laminar patterns of cortico-cortical connections

2021 ◽  
Author(s):  
Sarah F. Beul ◽  
Alexandros Goulas ◽  
Claus C. Hilgetag
Keyword(s):  
Structural Connectivity ◽  
Macaque Monkey ◽  
Brain Regions ◽  
Adult Brain ◽  
Mammalian Brain ◽  
Cortical Connections ◽  
Cortical Projections ◽  
Structural Connections ◽  
High Degree ◽  
The Brain

AbstractStructural connections between cortical areas form an intricate network with a high degree of specificity. Many aspects of this complex network organization in the adult mammalian cortex are captured by an architectonic type principle, which relates structural connections to the architectonic differentiation of brain regions. In particular, the laminar patterns of projection origins are a prominent feature of structural connections that varies in a graded manner with the relative architectonic differentiation of connected areas in the adult brain. Here we show that the architectonic type principle is already apparent for the laminar origins of cortico-cortical projections in the immature cortex of the macaque monkey. We find that prenatal and neonatal laminar patterns correlate with cortical architectonic differentiation, and that the relation of laminar patterns to architectonic differences between connected areas is not substantially altered by the complete loss of visual input. Moreover, we find that the degree of change in laminar patterns that projections undergo during development varies in proportion to the relative architectonic differentiation of the connected areas. Hence, it appears that initial biases in laminar projection patterns become progressively strengthened by later developmental processes. These findings suggest that early neurogenetic processes during the formation of the brain are sufficient to establish the characteristic laminar projection patterns. This conclusion is in line with previously suggested mechanistic explanations underlying the emergence of the architectonic type principle and provides further constraints for exploring the fundamental factors that shape structural connectivity in the mammalian brain.

Physiology, Pharmacology, and Topography of Cholinergic Neocortical Oscillations In Vitro

1997 ◽  
Vol 77 (5) ◽  
pp. 2427-2445 ◽  
Author(s):  
Heath S. Lukatch ◽  
M. Bruce Maciver
Keyword(s):  
Current Source ◽  
Brain Slices ◽  
Receptor Activation ◽  
Brain Regions ◽  
Oscillatory Activity ◽  
Cortical Layers ◽  
Eeg Activity ◽  
Layer 2

Lukatch, Heath S. and M. Bruce MacIver. Physiology, pharmacology, and topography of cholinergic neocortical oscillations in vitro. J. Neurophysiol. 77: 2427–2445, 1997. Rat neocortical brain slices generated rhythmic extracellular field [microelectroencephalogram (micro-EEG)] oscillations at theta frequencies (3–12 Hz) when exposed to pharmacological conditions that mimicked endogenous ascending cholinergic and GABAergic inputs. Use of the specific receptor agonist and antagonist carbachol and bicuculline revealed that simultaneous muscarinic receptor activation and γ-aminobutyric acid-A (GABAA)-mediated disinhibition werenecessary to elicit neocortical oscillations. Rhythmic activity was independent of GABAB receptor activation, but required intact glutamatergic transmission, evidenced by blockade or disruption of oscillations by 6-cyano-7-nitroquinoxaline-2,3-dione and (±)-2-amino-5-phosphonovaleric acid, respectively. Multisite mapping studies showed that oscillations were localized to areas 29d and 18b (Oc2MM) and parts of areas 18a and 17. Peak oscillation amplitudes occurred in layer 2/3, and phase reversals were observed in layers 1 and 5. Current source density analysis revealed large-amplitude current sinks and sources in layers 2/3 and 5, respectively. An initial shift in peak inward current density from layer 1 to layer 2/3 indicated that two processes underlie an initial depolarization followed by oscillatory activity. Laminar transections localized oscillation-generating circuitry to superficial cortical layers and sharp-spike-generating circuitry to deep cortical layers. Whole cell recordings identified three distinct cell types based on response properties during rhythmic micro-EEG activity: oscillation-on (theta-on) and -off (theta-off) neurons, and transiently depolarizing glial cells. Theta-on neurons displayed membrane potential oscillations that increased in amplitude with hyperpolarization (from −30 to −90 mV). This, taken together with a glutamate antagonist-induced depression of rhythmic micro-EEG activity, indicated that cholinergically driven neocortical oscillations require excitatory synaptic transmission. We conclude that under the appropriate pharmacological conditions, neocortical brain slices were capable of producing localized theta frequency oscillations. Experiments examining oscillation physiology, pharmacology, and topography demonstrated that neocortical brain slice oscillations share many similarities with the in vivo and in vitro theta EEG activity recorded in other brain regions.

scholarly journals Taste quality representation in the human brain

2019 ◽  
Author(s):  
Jason A. Avery ◽  
Alexander G. Liu ◽  
John E. Ingeholm ◽  
Cameron D. Riddell ◽  
Stephen J. Gotts ◽  
...  
Keyword(s):  
Human Brain ◽  
Cortical Neurons ◽  
Brain Regions ◽  
Taste Quality ◽  
7 Tesla ◽  
Mammalian Brain ◽  
High Magnetic Field Strength ◽  
Magnetic Resonance Imaging Mri ◽  
Spatial Locations ◽  
Univariate Analyses

SUMMARYIn the mammalian brain, the insula is the primary cortical substrate involved in the perception of taste. Recent imaging studies in rodents have identified a gustotopic organization in the insula, whereby distinct insula regions are selectively responsive to one of the five basic tastes. However, numerous studies in monkeys have reported that gustatory cortical neurons are broadly-tuned to multiple tastes, and tastes are not represented in discrete spatial locations. Neuroimaging studies in humans have thus far been unable to discern between these two models, though this may be due to the relatively low spatial resolution employed in taste studies to date. In the present study, we examined the spatial representation of taste within the human brain using ultra-high resolution functional magnetic resonance imaging (MRI) at high magnetic field strength (7-Tesla). During scanning, participants tasted sweet, salty, sour and tasteless liquids, delivered via a custom-built MRI-compatible tastant-delivery system. Our univariate analyses revealed that all tastes (vs. tasteless) activated primary taste cortex within the bilateral dorsal mid-insula, but no brain region exhibited a consistent preference for any individual taste. However, our multivariate searchlight analyses were able to reliably decode the identity of distinct tastes within those mid-insula regions, as well as brain regions involved in affect and reward, such as the striatum, orbitofrontal cortex, and amygdala. These results suggest that taste quality is not represented topographically, but by a combinatorial spatial code, both within primary taste cortex as well as regions involved in processing the hedonic and aversive properties of taste.

scholarly journals Acute stress enhances adult rat hippocampal neurogenesis and activation of newborn neurons via secreted astrocytic FGF2

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Elizabeth D Kirby ◽  
Sandra E Muroy ◽  
Wayne G Sun ◽  
David Covarrubias ◽  
Megan J Leong ◽  
...  
Keyword(s):  
Basolateral Amygdala ◽  
Acute Stress ◽  
Memory Function ◽  
Brain Regions ◽  
Hippocampal Neurogenesis ◽  
Mammalian Brain ◽  
Stress Hormone ◽  
Adult Rat ◽  
Neural Stem Progenitor Cells ◽  
Newborn Neurons

Stress is a potent modulator of the mammalian brain. The highly conserved stress hormone response influences many brain regions, particularly the hippocampus, a region important for memory function. The effect of acute stress on the unique population of adult neural stem/progenitor cells (NPCs) that resides in the adult hippocampus is unclear. We found that acute stress increased hippocampal cell proliferation and astrocytic fibroblast growth factor 2 (FGF2) expression. The effect of acute stress occurred independent of basolateral amygdala neural input and was mimicked by treating isolated NPCs with conditioned media from corticosterone-treated primary astrocytes. Neutralization of FGF2 revealed that astrocyte-secreted FGF2 mediated stress-hormone-induced NPC proliferation. 2 weeks, but not 2 days, after acute stress, rats also showed enhanced fear extinction memory coincident with enhanced activation of newborn neurons. Our findings suggest a beneficial role for brief stress on the hippocampus and improve understanding of the adaptive capacity of the brain.

scholarly journals Optogenetic spatial and temporal control of cortical circuits on a columnar scale

2016 ◽  
Vol 115 (2) ◽  
pp. 1043-1062 ◽  
Author(s):  
Arani Roy ◽  
Jason J. Osik ◽  
Neil J. Ritter ◽  
Shen Wang ◽  
James T. Shaw ◽  
...  
Keyword(s):  
Visual Stimulation ◽  
Liquid Crystal Display ◽  
Brain Regions ◽  
Cortical Activation ◽  
Mammalian Brain ◽  
Optogenetic Stimulation ◽  
Brain Surface ◽  
Stimulation System ◽  
Circuit Function ◽  
Stimulation Of

Many circuits in the mammalian brain are organized in a topographic or columnar manner. These circuits could be activated—in ways that reveal circuit function or restore function after disease—by an artificial stimulation system that is capable of independently driving local groups of neurons. Here we present a simple custom microscope called ProjectorScope 1 that incorporates off-the-shelf parts and a liquid crystal display (LCD) projector to stimulate surface brain regions that express channelrhodopsin-2 (ChR2). In principle, local optogenetic stimulation of the brain surface with optical projection systems might not produce local activation of a highly interconnected network like the cortex, because of potential stimulation of axons of passage or extended dendritic trees. However, here we demonstrate that the combination of virally mediated ChR2 expression levels and the light intensity of ProjectorScope 1 is capable of producing local spatial activation with a resolution of ∼200–300 μm. We use the system to examine the role of cortical activity in the experience-dependent emergence of motion selectivity in immature ferret visual cortex. We find that optogenetic cortical activation alone—without visual stimulation—is sufficient to produce increases in motion selectivity, suggesting the presence of a sharpening mechanism that does not require precise spatiotemporal activation of the visual system. These results demonstrate that optogenetic stimulation can sculpt the developing brain.

A porcine brain-wide RNA editing landscape

2020 ◽  
Author(s):  
Jinrong Huang ◽  
Lin Lin ◽  
Zhanying Dong ◽  
Ling Yang ◽  
Tianyu Zheng ◽  
...  
Keyword(s):  
Rna Editing ◽  
Repetitive Sequences ◽  
Brain Regions ◽  
Mammalian Brain ◽  
Protein Coding ◽  
Porcine Brain ◽  
Coding Regions ◽  
Pig Brain ◽  
Genome Wide ◽  
A Genome

Abstract Adenosine-to-inosine (A-to-I) RNA editing, catalyzed by ADAR enzymes, is an essential post-transcriptional modification. Although hundreds of thousands of RNA editing sites have been reported in mammals, brain-wide analysis of the RNA editing in the mammalian brain remains rare. Here, a genome-wide RNA editing investigation is performed in 119 samples, representing 30 anatomically defined subregions in the pig brain. We identify a total of 682,037 A-to-I RNA editing sites of which 97% are not identified before. Within the pig brain, cerebellum and olfactory bulb are regions with most edited transcripts. The editing level of sites residing in protein-coding regions are similar across brain regions, whereas region-distinct editing is observed in repetitive sequences. Highly edited conserved recoding events in pig and human brain are found in neurotransmitter receptors, demonstrating the evolutionary importance of RNA editing in neurotransmission functions. The porcine brain-wide RNA landscape provides a rich resource to better understand the evolutionally importance of post-transcriptional RNA editing.

Mesozoic mammals and early mammalian brain diversity

2003 ◽  
Vol 26 (5) ◽  
pp. 556-557 ◽  
Author(s):  
Emmanuel Gilissen ◽  
Thierry Smith
Keyword(s):  
Middle Ear ◽  
Brain Regions ◽  
Mammalian Brain ◽  
Fossil Remains ◽  
Ear Ossicles ◽  
Mesozoic Mammals ◽  
Brain Expansion ◽  
The Relationship ◽  
The Brain

Fossil remains witness the relationship between the appearance of the middle ear and the expansion of the brain in early mammals. Nevertheless, the lack of detachment of ear ossicles in the mammaliaform Morganucodon, despite brain enlargement, points to other factors that triggered brain expansion in early mammals. Moreover, brain expansion in some early mammalian groups seems to have favored brain regions other than the cortex.

scholarly journals Vasoactive intestinal peptide as a mediator of the effects of a supergene on social behaviour

2020 ◽  
Vol 287 (1924) ◽  
pp. 20200196
Author(s):  
Brent M. Horton ◽  
Christina M. Michael ◽  
Mackenzie R. Prichard ◽  
Donna L. Maney
Keyword(s):  
Vasoactive Intestinal Peptide ◽  
Brain Regions ◽  
Anterior Hypothalamus ◽  
Causal Role ◽  
Zonotrichia Albicollis ◽  
Free Living ◽  
Parental Behaviour ◽  
Genomic Architecture ◽  
Parental Phenotype ◽  
Behavioural Phenotypes

Supergenes, or linked groups of alleles that are inherited together, present excellent opportunities to understand gene–behaviour relationships. In white-throated sparrows ( Zonotrichia albicollis ), a supergene on the second chromosome associates with a more aggressive and less parental phenotype. This supergene includes the gene for vasoactive intestinal peptide (VIP), a neuropeptide known to play a causal role in both aggression and parental behaviour. Here, using a free-living population, we compared the levels of VIP mRNA between birds with and without the supergene. We focused on the anterior hypothalamus and infundibular region, two brain regions containing VIP neurons known to play a causal role in aggression and parental behaviour, respectively. First, we show that the supergene enhances VIP expression in the anterior hypothalamus and that expression positively predicts vocal aggression independently of genotype in both sexes. Next, we show that the supergene reduces VIP expression in the infundibular region, which suggests reduced secretion of prolactin, a pro-parental hormone. Thus, the patterns of VIP expression in these two regions are consistent with the enhanced aggression and reduced parental behaviour of birds with the supergene allele. Our results illustrate mechanisms by which elements of genomic architecture, such as supergenes, can contribute to the evolution of alternative behavioural phenotypes.

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