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PubMed1993

Reversed phase HPLC analysis of proenkephalin-related and prodynorphin-related end-products in the brain of a urodele amphibian, Ambystoma tigrinum.

Acid extracts of the brain of a urodele amphibian, Ambystoma tigrinum, were screened with radioimmunoassays specific for enkephalin-related products and dynorphin-related products. Following Sephadex G-50 column chromatography a peak of enkephalin-sized immunoreactive material was detected near the total volume of the column. The enkephalin-sized immunoreactivity was further analyzed by reversed phase HPLC. This analysis detected peaks of authentic Met-enkephalin and Leu-enkephalin. However, the molar ratio of Met-enkephalin to Leu-enkephalin in the brain of this amphibian was approximately 80:1. These observations would suggest that the Leu-enkephalin detected in the brain of Ambystoma may be derived from a source other than the Proenkephalin precursor. Neither Met-enkephalin-RGL or Met-enkephalin-RF were detected by radioimmunoassay in brain extracts from this urodele. However, following digestion with trypsin and carboxypeptidase B, a novel peak of C-terminally extended Met-enkephalin was detected. Two peaks of Prodynorphin-related products were also detected following gel filtration chromatography. These immunoreactive forms were detected using antisera specific for alpha-neo-endorphin and dynorphin B(1-13). No immunoreactive forms with antigenic determinants similar to mammalian dynorphin A(1-17) or dynorphin A(1-8) were detected in this species. Reversed phase HPLC analysis indicated that the major form of urodele alpha-neo-endorphin eluted with the same retention time as synthetic mammalian alpha-neo-endorphin. Urodele dynorphin B(1-13)-related immunoreactivity eluted as a single peak, however, this form did not elute with the same retention time as synthetic mammalian dynorphin B(1-13).(ABSTRACT TRUNCATED AT 250 WORDS)

Ambystoma↗

PubMed2005

Failed central nervous system regeneration: a downside of immune privilege?

Immunity is required to eliminate dangerous or degenerated material and to support regeneration, but also causes significant parenchymal damage. In the eye and the brain, in which cornea and lens poorly regenerate and neurons are hardly replaceable, early transplantation experiments demonstrated remarkable tolerance to various grafts. This "immunologically privileged status" (Billingham and Boswell, 1953) may reflect evolutionary pressure to downmodulate certain actions of immune cells within particularly vulnerable tissues. As an example, tolerating certain "neurotrophic" viruses may often be a more successful strategy for survival than the elimination of all infected neurons. While several constitutive and inducible signals maintaining or re-establishing immune tolerance within the brain have been identified, it has also become evident that the resulting anti-inflammatory environment limits certain beneficial effects of neuroinflammation such as neurotrophin secretion or glutamate buffering by T-cells and the clearance of growth-inhibiting myelin or amyloid. Following spinal cord injury, the costs and benefits of neuroinflammation seem to come close because enhancing as well as suppressing innate or adaptive immunity caused amelioration and aggravation of functional regeneration in similar experiments. Evaluating such balances has also begun in (animal models of) Alzheimer's disease, central nervous system trauma, and stroke, and the appreciation of the beneficial side of neuroinflammation has caused a rethinking of the ill-defined use of immune suppressants. As dual roles for individual molecules have been recognized (Merrill and Benveniste, 1996), we are uncovering an already fine-tuned system, but the challenge remains to further support beneficial immune cascades without causing additional damage, and vice versa.

Animals↗

PubMed2003

Evidence from human scalp electroencephalograms of global chaotic itinerancy.

My objective of this study was to find evidence of chaotic itinerancy in human brains by means of noninvasive recording of the electroencephalogram (EEG) from the scalp of normal subjects. My premise was that chaotic itinerancy occurs in sequences of cortical states marked by state transitions that appear as temporal discontinuities in neural activity patterns. I based my study on unprecedented advances in spatial and temporal resolution of the phase of oscillations in scalp EEG. The spatial resolution was enhanced by use of a high-density curvilinear array of 64 electrodes, 189 mm in length, with 3 mm spacing. The temporal resolution was advanced to the limit provided by the digitizing step, here 5 ms, by use of the Hilbert transform. The numerical derivative of the analytic phase revealed plateaus in phase that lasted on the order of 0.1 s and repeated at rates in the theta (3-7 Hz) or alpha (7-12 Hz) ranges. The plateaus were bracketed by sudden jumps in phase that usually took place within 1 to 2 digitizing steps. The jumps were commonly synchronized in each cerebral hemisphere over distances of up to 189 mm, irrespective of the orientation of the array. The jumps were usually not synchronized across the midline separating the hemisphere or across the sulcus between the frontal and parietal lobes. I believe that the widespread synchrony of the jumps in analytic phase manifest a metastable cortical state in accord with the theory of self-organized criticality. The jumps appear to be subcritical bifurcations. They reflect the aperiodic evolution of brain states through sequences of attractors that on access support the experience of remembering.

Brain↗

PubMed2006

Cytoarchitectonic identification and probabilistic mapping of two distinct areas within the anterior ventral bank of the human intraparietal sulcus.

Anatomical studies in the macaque cortex and functional imaging studies in humans have demonstrated the existence of different cortical areas within the intraparietal sulcus (IPS). Such functional segregation, however, does not correlate with presently available architectonic maps of the human brain. This is particularly true for the classical Brodmann map, which is still widely used as an anatomical reference in functional imaging studies. The aim of this cytoarchitectonic mapping study was to use previously defined algorithms to determine whether consistent regions and borders can be found within the cortex of the anterior IPS in a population of 10 post-mortem human brains. Two areas, the human intraparietal area 1 (hIP1) and the human intraparietal area 2 (hIP2), were delineated in serial histological sections of the anterior, lateral bank of the human IPS. The region hIP1 is located posterior and medial to hIP2, and the former is always within the depths of the IPS. The latter, on the other hand, sometimes reaches the free surface of the superior parietal lobule. The delineations were registered to standard reference space, and probabilistic maps were calculated, thereby quantifying the intersubject variability in location and extent of both areas. In the future, they can be a tool for analyzing structure-function relationships and a basis for determining degrees of homology in the IPS among anthropoid primates. We conclude that the human IPS has a more finely grained parcellation than shown in Brodmann's map.

Adult↗

PubMed2005

The dual origin hypothesis: an evolutionary brain-behavior framework for analyzing psychiatric disorders.

According to the dual origin hypothesis, the cerebral cortex of higher mammals evolved from two primordial brain structures, the amygdala and hippocampal formation. This developmental process defines the orderly principles of cortical connectivity and gives rise to functionally distinct ventral and dorsal systems within the cerebrum. This paper reviews the basic features of the dual origin theory. This model is then applied to understanding symptom production in a number of psychiatric illnesses, with particular reference to recent structural and functional imaging studies. In this paper I propose that psychiatric symptoms can be conceptualized as arising from abnormal processing within dorsal (time-space-motility) or ventral (meaning-motivation) systems, or from a disturbance in the functional interaction/balance between them. Within this framework, one can identify symptom-specific correlations that cross-traditional diagnostic boundaries, as well as potential mechanisms that may explain biologically valid diagnostic entities. Integrating evolutionary, connectional and functional bases across multiple species, the dual origin hypothesis offers a powerful neural systems model to help organize our understanding of psychiatric illness, therein suggesting novel approaches to diagnosis, prevention and treatment.

Animals↗

PubMed1984

New concepts on the structure of the neuronal networks: the miniaturization and hierarchical organization of the central nervous system. (Hypothesis).

The hypothesis is introduced that miniaturization of neuronal circuits in the central nervous system and the hierarchical organization of the various levels, where information handling can take place, may be the key to understand the enormous capability of the human brain to store engrams as well as its astonishing capacity to reconstruct and organize engrams and thus to perform highly sophisticated integrations. The concept is also proposed that in order to understand the relationship between the structural and functional plasticity of the central nervous system it is necessary to postulate the existence of memory storage at the network level, at the local circuit level, at the synaptic level, at the membrane level, and finally at the molecular level. Thus, memory organization is similar to the hierarchical organization of the various levels, where information handling takes place in the nervous system. In addition, each higher level plays a role in the reconstruction and organization of the engrams stored at lower levels. Thus, the trace of the functionally stored memory (i.e. its reconstruction and organization at various levels of storage) will depend not only on the chemicophysical changes in the membranes of the local circuits but also on the organization of the local circuits themselves and their associated neuronal networks.

Aging↗

PubMed1986

Sequence analysis of the cDNA encoding human liver glycogen phosphorylase reveals tissue-specific codon usage.

We have cloned the cDNA encoding glycogen phosphorylase (1,4-alpha-D-glucan:orthophosphate alpha-D-glucosyl-transferase, EC 2.4.1.1) from human liver. Blot-hybridization analysis using a large fragment of the cDNA to probe mRNA from rabbit brain, muscle, and liver tissues shows preferential hybridization to liver RNA. Determination of the entire nucleotide sequence of the liver message has allowed a comparison with the previously determined rabbit muscle phosphorylase sequence. Despite an amino acid identity of 80%, the two cDNAs exhibit a remarkable divergence in G+C content. In the muscle phosphorylase sequence, 86% of the nucleotides at the third codon position are either deoxyguanosine or deoxycytidine residues, while in the liver homolog the figure is only 60%, resulting in a strikingly different pattern of codon usage throughout most of the sequence. The liver phosphorylase cDNA appears to represent an evolutionary mosaic; the segment encoding the N-terminal 80 amino acids contains greater than 90% G+C at the third codon position. A survey of other published mammalian cDNA sequences reveals that the data for liver and muscle phosphorylases reflects a bias in codon usage patterns in liver and muscle coding sequences in general.

Animals↗

PubMed2002

The distribution and morphological characteristics of catecholaminergic cells in the brain of monotremes as revealed by tyrosine hydroxylase immunohistochemistry.

The present study describes the distribution and cellular morphology of catecholaminergic neurons in the CNS of two species of monotreme, the platypus (Ornithorhynchus anatinus) and the short-beaked echidna (Tachyglossus aculeatus). Tyrosine hydroxylase immunohistochemistry was used to visualize these neurons. The standard A1-A17, C1-C3 nomenclature was used for expediency, but the neuroanatomical names of the various nuclei have also been given. Monotremes exhibit catecholaminergic neurons in the diencephalon (A11, A12, A13, A14, A15), midbrain (A8, A9, A10), rostral rhombencephalon (A5, A6, A7), and medulla (A1, A2, C1, C2). The subdivisions of these neurons are in general agreement with those of other mammals, and indeed other amniotes. Apart from minor differences, those being a lack of A4, A3, and C3 groups, the catecholaminergic system of monotremes is very similar to that of other mammals. Catecholaminergic neurons outside these nuclei, such as those reported for other mammals, were not numerous with occasional cells observed in the striatum. It seems unlikely that differences in the sleep phenomenology of monotremes, as compared to other mammals, can be explained by these differences. The similarity of this system across mammalian and amniote species underlines the evolutionary conservatism of the catecholaminergic system.

Animals↗

PubMed1989

From the spectrin gene to the assembly of the membrane skeleton.

The complete nucleotide sequence coding for the chicken brain alpha-spectrin was determined. It comprises the entire coding frame, 5'- and 3'-untranslated sequences terminating in a poly(A)-tail. The deduced amino acid sequence shows that the alpha-chain contains 22 segments, 20 of which correspond to the typical 106 residue repeat of the human erythrocyte spectrin. Some segments non-homologous to the repeat structure reside in the middle and COOH-terminal regions. Sequence comparisons with other proteins show that these segments evidently harbour some structural and functional features such as: homology to alpha-actinin and dystrophin, two typical EF-hand structures (calcium-binding) and a putative calmodulin-binding site in the COOH-terminus and a sequence homologous to various src-tyrosine kinases and to phospholipase C in the middle of the molecule. Comparison of our sequence with other partial alpha-spectrin sequences shows that alpha-spectrin is well conserved in different species and that the human erythrocyte alpha-spectrin is divergent.

Amino Acid Sequence↗

PubMed2005

Brain maps, great and small: lessons from comparative studies of primate visual cortical organization.

In this paper, we review evidence from comparative studies of primate cortical organization, highlighting recent findings and hypotheses that may help us to understand the rules governing evolutionary changes of the cortical map and the process of formation of areas during development. We argue that clear unequivocal views of cortical areas and their homologies are more likely to emerge for "core" fields, including the primary sensory areas, which are specified early in development by precise molecular identification steps. In primates, the middle temporal area is probably one of these primordial cortical fields. Areas that form at progressively later stages of development correspond to progressively more recent evolutionary events, their development being less firmly anchored in molecular specification. The certainty with which areal boundaries can be delimited, and likely homologies can be assigned, becomes increasingly blurred in parallel with this evolutionary/developmental sequence. For example, while current concepts for the definition of cortical areas have been vindicated in allowing a clarification of the organization of the New World monkey "third tier" visual cortex (the third and dorsomedial areas, V3 and DM), our analyses suggest that more flexible mapping criteria may be needed to unravel the organization of higher-order visual association and polysensory areas.

Anatomy, Comparative↗

PubMedDate not supplied

Detection of Met-enkephalin in the CNS of the teleosts, Anguilla rostrata and Oncorhynchus kisutch.

Acid extracts of the brains of the American eel, Anguilla rostrata, and the coho salmon, Oncorhynchus kisutch, were screened for enkephalin-related products and dynorphin-related products. Following Sephadex G-50 column chromatography, a peak of Met-enkephalin-related immunoreactivity was detected near the total volume of the column for both species. No higher molecular weight forms of Met-enkephalin-related material were detected, nor were any immunoreactive forms with antigenic determinants similar to mammalian dynorphin A(1-17), dynorphin A(1-8), dynorphin B(1-13) or alpha-neo-endorphin detected for either species. The enkephalin-sized immunoreactivity was further analyzed by reverse phase HPLC. For both species, a peak of authentic Met-enkephalin was detected. However, Leu-enkephalin, Met-enkephalin-RGL and Met-enkephalin-RF were not detected by RIA in either species. In addition, no novel C-terminally extended forms of Met-enkephalin were detected in either species. Finally, opiate receptor binding activity was only found associated with the peak of immunoreactive Met-enkephalin.

Anguilla↗

PubMed2006

Evidence that the adaptive allele of the brain size gene microcephalin introgressed into Homo sapiens from an archaic Homo lineage.

At the center of the debate on the emergence of modern humans and their spread throughout the globe is the question of whether archaic Homo lineages contributed to the modern human gene pool, and more importantly, whether such contributions impacted the evolutionary adaptation of our species. A major obstacle to answering this question is that low levels of admixture with archaic lineages are not expected to leave extensive traces in the modern human gene pool because of genetic drift. Loci that have undergone strong positive selection, however, offer a unique opportunity to identify low-level admixture with archaic lineages, provided that the introgressed archaic allele has risen to high frequency under positive selection. The gene microcephalin (MCPH1) regulates brain size during development and has experienced positive selection in the lineage leading to Homo sapiens. Within modern humans, a group of closely related haplotypes at this locus, known as haplogroup D, rose from a single copy approximately 37,000 years ago and swept to exceptionally high frequency (approximately 70% worldwide today) because of positive selection. Here, we examine the origin of haplogroup D. By using the interhaplogroup divergence test, we show that haplogroup D likely originated from a lineage separated from modern humans approximately 1.1 million years ago and introgressed into humans by approximately 37,000 years ago. This finding supports the possibility of admixture between modern humans and archaic Homo populations (Neanderthals being one possibility). Furthermore, it buttresses the important notion that, through such adminture, our species has benefited evolutionarily by gaining new advantageous alleles. The interhaplogroup divergence test developed here may be broadly applicable to the detection of introgression at other loci in the human genome or in genomes of other species.

Adaptation, Biological↗

PubMed1994

Evolutionary implications of the family of 14-3-3 brain protein homologs in Arabidopsis thaliana.

The GF14 family of proteins in Arabidopsis thaliana consists of a homologous group of polypeptides ranging in size from approximately 27 kDa to approximately 32 kDa. As a group, GF14 proteins are also homologous to a family of mammalian proteins most commonly referred to as 14-3-3 proteins. Several distinct and different biochemical activities have been historically attributed to the various isoforms of the mammalian 14-3-3 proteins. These data present the possibility that the various activities are performed by functionally distinct lineages of the gene family. Here we present phylogenetic analyses based on the derived amino acid sequences of five GF14 isoforms expressed in Arabidopsis suspension-cultured cells. A high degree of sequence integrity is apparent in the various Arabidopsis isoforms, and the overall structures of the plant forms are quite conserved with regard to the structures of the known mammalian forms. These gene phylogenies indicate no evolutionary conservation of specific isoform lineages within both plants and animals. Rather, the evolutionary history of this protein appears to be characterized by a separate radiation of plant and animal forms from a common ancestral sequence. Even though the plant and animal forms have evolved independently since that ancestral split, large domains are conserved in both major lineages.

14-3-3 Proteins↗

PubMed2005

Cyto- and chemoarchitecture of the amygdala of a monotreme, Tachyglossus aculeatus (the short-beaked echidna).

We have examined the cyto- and chemoarchitecture of the temporal and extended amygdala in the brain of a monotreme (the short-beaked echidna Tachyglossus aculeatus) using Nissl and myelin staining, enzyme histochemistry for acetylcholine esterase and NADPH diaphorase, immunohistochemistry for calcium binding proteins (parvalbumin, calbindin and calretinin) and tyrosine hydroxylase. While the broad subdivisions of the eutherian temporal amygdala were present in the echidna brain, there were some noticeable differences. No immunoreactivity for parvalbumin or calretinin for somata was found in the temporal amygdala of the echidna. The nucleus of the lateral olfactory tract could not be definitively identified and the medial nucleus of amygdala appeared to be very small in the echidna. Calbindin immunoreactive neurons were most frequently found in the ventrolateral part of the lateral nucleus, intraamygdaloid parts of the bed nucleus of the stria terminalis and the lateral part of the central nucleus. Neurons strongly reactive for NADPH diaphorase with filling of the dendritic tree were found mainly scattered through the cortical, central and lateral subnuclei, while neurons showing only somata reactivity for NADPH diaphorase were concentrated in the basomedial and basolateral subnuclei. Most of the components of the extended amygdala of eutherians could also be identified in the echidna. Volumetric analysis indicated that the temporal amygdala in both the platypus and echidna is small compared to the same structure in both insectivores and primates, with the central and medial components of the temporal amygdala being particularly small.

Acetylcholinesterase↗

PubMed1996

Connections of octaval and lateral line nuclei of the medulla in the goldfish, including the cytoarchitecture of the secondary octaval population in goldfish and catfish.

Cytoarchitectural analyses combined with injections of the tracer horseradish peroxidase in various structures in the brain of the goldfish, Carassius auratus, have defined some of the major components of acoustic and lateral line mechanosensory circuits between the medulla and midbrain. The main acoustic receptor in Carassius, the saccule, is known to provide a major input to the dorsomedial zone of the descending octaval nucleus. The dorsomedial zone in turn projects bilaterally to the secondary octaval population (SO) and to nucleus centralis of the torus semicircularis. The SO is composed of three major subdivisions which are also present in a related otophysan, the catfish Ictalurus punctatus. The SO in Carassius projects bilaterally to nucleus centralis and to the saccular recipient zones of the ipsilateral descending octaval nucleus. By contrast, the mechanosensory lateral line receptors are known to direct most of their input to nucleus medialis. Nucleus medialis in turn projects bilaterally to nucleus praeeminentialis, nucleus ventrolateralis of the torus semicircularis, and the optic tectum, and to the contralateral nucleus medialis. We also provide evidence for a bilateral projection of nucleus medialis to the sensory trigeminal nucleus, and for a reciprocal input from the sensory trigeminal nucleus to the ipsilateral nucleus medialis.

Animals↗

PubMedDate not supplied

The serotoninergic system of the brain of the lamprey, Lampetra fluviatilis: an evolutionary perspective.

The distribution of serotonin(5HT)-immunoreactive cell bodies, nerve fibers and terminals was investigated by light microscopy in the lamprey Lampetra fluviatilis. Twenty-three distinct groups of 5HT neuronal somata were identified from diencephalic to rhombencephalic levels in the brain. The diencephalon contained a subependymal population of immunoreactive cells in contact with the cerebrospinal fluid (CSF), which could be subdivided into five separate groups situated in the hypothalamus and ventral thalamus; five additional groups of immunoreactive diencephalic neurons, situated in the dorsal thalamus and thalamo-pretectum, which were not in contact with the CSF, were also identified. In the midbrain, in addition to a few labelled neurons in the optic tectum, two structures containing immunoreactive cells were identified in the tegmentum mesencephali. None of these 5HT cells corresponded to the retinopetal neurons which are situated in the same region. A very large number of 5HT neurons were observed in the hindbrain which could be divided into seven groups in the isthmus rhombencephali and a further three in the rhombencephalon proper. Immunoreactive fibers and terminals were widely distributed throughout the neuraxis. In the telencephalon two 5HT fibers assemblies, lateral and medial, could be identified which terminated in both pallial and subpallial structures. The richest serotoninergic innervation in the telencephalon was found in the lateral portion of the primordium hippocampi and the medial part of the corpus striatum. In the diencephalon, the distribution of immunoreactive fibers and terminals was heterogeneous, being most pronounced in the lateral hypothalamic area and in the infundibulum. The densest arborization of fibers in the mesencephalon was found in the stratum fibrosum et cellulare externum of the optic tectum, a major site of retinal projection, and in the nucleus interpeduncularis mesencephali as well as in the oculomotor nuclei. The rhombencephalon is richly endowed with serotoninergic fibers and terminals, many labelled arborizations being found in the nuclei isthmi rhombencephali and around the nucleus motorius nervi trigemini. Comparative analysis of the serotoninergic systems of petromyzontiforms and gnathostomes indicates that the evolution of this system involves a progressive elimination of the rostral immunoreactive cells and an increasing complexity of the caudal population of serotoninergic neurons.

Animals↗

PubMed2000

Comparative immunocytochemical study of FMRFamide neuronal system in the brain of Danio rerio and Acipenser ruthenus during development.

The distribution of FMRFamide-like immunoreactive (ir) neurons and fibers was investigated in the central nervous system of developing zebrafish and juvenile sturgeon (sterlet). Adult zebrafish was also studied. In zebrafish embryos FMRFamide-ir elements first appeared 30 h post-fertilization (PF). Ir somata were located in the olfactory placode and in the ventral diencephalon. FMRFamide-ir fibers originating from diencephalic neurons were found in the ventral telencephalon and in ventral portions of the brainstem. At 48 h PF, the ir perikarya in the olfactory placode displayed increased immunoreactivity and stained fibers emerged from the somata. At 60 h PF, bilaterally, clusters of FMRFamide-ir neurons were found along the rostro-caudal axis of the brain, from the olfactory placode to rostral regions of the ventro-lateral telencephalon. At 60 h PF, numerous ir fibers appeared in the dorsal telencephalon, optic lobes, optic nerves, and retina. Except for ir fibers in the hypophysis at the age of 72 h PF, and a few ir cells in the nucleus olfacto-retinalis (NOR) at the age of 2 months PF, no major re-organization was noted in subsequent ontogenetic stages. The number of stained NOR neurons increased markedly in sexually mature zebrafish. In adult zebrafish, other ir neurons were located in the dorsal zones of the periventricular hypothalamus and in components of the nervus terminalis. We are inclined to believe that neurons expressing FMRFamide originate in the olfactory placode and in the ventricular ependyma in the hypothalamus. On the same grounds, a dual origin of FMRFamide-ir neurons is inferred in the sturgeon, an ancestral bony fish: prior to the observation of ir cells in the nasal area and in the telencephalon stained neurons were noted in circumventricular hypothalamic regions.

Age Factors↗

PubMed1978

Evolutionary adaptation of membranes to temperature.

The "fluidity" of brain synaptosomal membrane preparations of arctic and hot-springs fish species, two temperature water fish species acclimated to different seasonal temperatures, and two mammals was estimated using the fluorescence polarization technique. At all measurement temperatures, the fluidity decreased in the order: arctic sculpin, 5 degrees-acclimated goldfish, 25 degrees-acclimated goldfish, desert pupfish, and rat. This correlated with increasing adaptation or body (i.e., cellular) temperatures of 0 degrees, 5 degrees, 25 degrees, 34 degrees, and 37 degrees and suggested a partial compensation of membrane fluidity for environmental temperature that occurs over the evolutionary time period as well as during laboratory (seasonal) acclimation. Evolutionary adaptation of relatively stenothermal species to constant thermal environments resulted in a more complete compensation than laboratory (seasonal) acclimation. Each compensation is accompanied by differences in the saturation of membrane phosphoglycerides. At increased cellular temperatures the proportion of saturated fatty acids increased and the unsaturation index decreased; the correlation between these indices and the measured expression of membrane dynamic structure was highly significant. It is concluded that the homeoviscous compensation of synaptic membrane function is an important component of temperature adaptation.

Adaptation, Physiological↗