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As sea levels rise, coastal wetlands are encountering physical barriers to inland migration in a phenomenon known as “coastal squeeze.” Specifically, wetlands are being squeezed between sea-level rise on one side and human development on the other preventing their natural ability to adapt by moving to higher ground. State and local coastal governments have legal and policy tools available to adapt to sea-level rise and limit the impacts of coastal squeeze on migrating wetlands. This article presents legal and policy tools and considerations governments could evaluate to facilitate long-term wetland conservation and migration to maximize benefits for people, the environment, and economies. This article first provides legal background on the law and federal, state, and local actors that could impact state and local decisions. This article then identifies five primary components of a comprehensive wetland migration strategy for state and local coastal governments: (1.) data; (2.) planning; (3.) voluntary land acquisitions; (4.) legal tools; and (5.) community engagement. This article also includes case study examples. Decisionmakers could potentially integrate any of these five components into existing coastal, environmental, land-use, and climate adaptation efforts to align policy objectives to protect wetlands across different programs and projects.

The purpose of this research was to ascertain whether gravitational cues contribute to localisation ability of mentally represented cutaneous targets. Eight right-handed male subjects were asked to use each hand to point accurately toward four points in the anterior trunk midline solely on the basis of the mental representation of their position along the trunk while standing upright and while lying supine. It was found that subjects were more accurate when performing in the upright posture. However, statistical analysis of the mean constant transverse errors of pointing showed that neither posture nor target factors had any significant effect on pointing accuracy. On the contrary, analysis of the mean constant longitudinal errors showed that both the posture and target factors were significant. Subjects pointed caudally to the target locations and made the largest errors, which were on the order of centimeters, when performing in the horizontal posture. These findings indicate that gravitational cues are critical in accurately localising mentally represented cutaneous targets.

The effects of selective transection of the rostralmost portion of the corpus callosum, which contains fibres interconnecting the motor cortices of the two hemispheres, on frequency of occurrence and latency of conditioned responses (CRs) in both eyes were examined in seven cats trained to blink in response to a 500-ms tone. A 100-ms air-puff delivered to one eye only (ipsilateral eye) 400 ms after tone onset was used as an unconditioned stimulus. Both before and after callosal lesion, bilateral CRs were the most frequent response pattern. Following callosal lesion, a statistically significant reduction in the percentage of CRs in at least one eye was observed in only two cats. In all seven animals, both before and after callosal lesion, the mean CR latencies of the ipsilateral eye were significantly shorter than those of the contralateral eye. Callosal lesion caused a significant increase in the mean CR latencies of both eyes in all subjects. These results provide evidence that the two hemispheres influence each other in controlling conditioned bilateral blinking by reciprocally exchanging facilitatory signals contributing to initiation of CRs in both eyes.

In six chronic cats experiments were carried out to examine the motor effects elicited by microstimulation of the rostral portion of the corpus callosum (CC) which contains fibres interconnecting the motor cortices of the two hemispheres. Serial dorso-ventral penetrations were stereotaxically performed along the rostro-caudal extent of the CC at 0.25-0.5 mm intervals. Motor responses, consisting of very discrete contractions of shoulder, whisker and eyelid muscles, were obtained upon stimulation of about the most rostral 4 mm at intensities lower than 50 microA. At threshold the responses appeared in only one body region and were often unilateral. A light increase in current gave rise to symmetrical bilateral effects. Thresholds were the lowest in the middle of CC and gradually rose towards its dorsal and ventral surfaces. In the course of a penetration an effect once elicited persisted until either the threshold became higher than 50 microA or the ventral edge was reached. All motor effects had thresholds higher than 10 microA. Contractions of shoulder, whisker and eyelid muscles at a threshold lower than 20 microA were obtained in 62.7%, 25.7% and 54.3% of penetrations, respectively. Shoulder and eyelid muscles were represented in the rostral and caudal half of the effective zone, respectively, whereas the representation of whisker muscles overlapped with the other two in the rostral third or the middle part of the effective zone. Single fibres driven by palpation of muscles responding to microstimulation or by movements of the joint mobilized by microstimulation were found at the most rostral sites, whereas units responding to hair displacement over or around the affected muscles were isolated mainly at the most caudal sites. It was inferred that functionally homogeneous callosal fibres are clustered in bundles arranged in dorso-ventrally oriented laminae. The somatotopic representation of the motor effects elicited by microstimulation along the rostro-caudal extent of the effective zone should be the consequence of the serial arrangement of these partially overlapping laminae.

Microstimulation of the rostral portion of the corpus callosum (CC) was carried out on 21 awake kittens ranging in age from 45 to 105 days to determine the age at which motor responses first appeared and that at which they assumed functional adult-like properties. Motor responses to microstimulation first appeared over an interval ranging from 78-86 days postnatally. As in adults, they consisted of discrete, well-localized contractions of shoulder, whisker, and eyelid muscles according to the stimulated sites. In the first days after their appearance, motor responses differed markedly from those in adults because: (a) they exhibited higher thresholds; (b) they did not faithfully follow pulse trains delivered at 10 s intervals; (c) they had variable and longer latencies. Thereafter, motor responses gradually became stable, faithfully followed suprathreshold stimulation delivered at 0.1/s frequency, and acquired lower thresholds and shorter latencies, until they exhibited adult-like properties at 93-100 days of age. Single-unit recordings were obtained from 138 fibres isolated in the same callosal region submitted to microstimulation in order to study the response properties of the callosal fibres to somatic stimuli in immature animals. On the basis of their reactivity to peripheral stimulation, fibres were classified into three main types: (1) unreactive units (58 fibres), which could not be driven by somatic stimuli. (2) Adult-like units (55 fibres), which were readily driven by somatic stimuli and were endowed with fixed and small receptive fields (RFs) indistinguishable from those of adults. (3) Immature units (25 fibres), which were unsteadily driven by somatic stimuli applied over large areas at the periphery. Neither the RFs nor the adequate stimuli could be reliably determined. This type of units was not found in the adult cat (Spidalieri et al. 1985). The proportion of unreactive units was the highest before the appearance of motor responses and gradually decreased, approaching the adult level after attaining adult-like motor responses. Conversely, the proportion of adult-like units was lowest before the appearance of motor responses and gradually increased, approaching the adult level after motor responses had acquired adult-like properties.

1. In the rostral part of the corpus callosum (somesthetic callosal region, SCR) fibres were identified, through which the callosally-projecting cells of the somatosensory areas transmit to the other hemisphere signals originated in the body surface. 2. With seriate macroelectrode penetrations it was found that, to some extent, the body surface is represented somatotopically in the rostrocaudal extent of the SCR. The strongest mass potentials to trigeminal, fore- and hindlimb stimulation were recorded from the rostral, middle and caudal portions of the SCR. The whisker region and the forelimb (both paws and proximal segments) appeared to have the widest callosal representation. 3. Ablation experiments showed that callosal somesthetic fibres originate in both SI and SII areas and that only impulses set up in the contralateral hemibody are relayed in these areas. Direct stimulation of the latter evoked within the SCR mass potentials whose rostrocaudal distribution parallels that of the peripherally evoked responses. 4. Exploring the SCR with microelectrodes, 43 spontaneously active fibres were isolated, all reactive to electrical and physiological stimulation of the related peripheral receptive fields. These were located in trigeminal (31 fibres), segmental (10 fibres) or both in trigeminal and segmental regions (2 fibres). The extent of the receptive fields and the reactivity characteristics of almost all the fibres sampled were lemniscal in type, and similar to those of the somatotopic neurones of cortical somatosensory areas.

In fifteen awake, chronic cats single-unit recordings were obtained from 316 fibres isolated in the rostral portion of the corpus callosum (CC). Altogether, 304 units were reactive to peripheral stimuli. They were fired by hair bending, light touch or light pressure (S units; 79.3%) or by gentle rotation of joints and/or by pressure on muscle bellies or tendons (D units; 20.7%). All the reactive units were endowed with small and unilateral receptive fields (RFs) located in trigeminal (49.7%) or segmentai (50.3%) regions. Trigeminal and forepaw units had the smallest RFs. All the trigeminal units were of the S type. Their RFs were located in either the ophthalmic, maxillar, and mandibular face districts or in the oral vestible. The vast majority of segmental units (146 out 153 fibres) had RFs in the forelimb. Very few units were fired by stimulation of the trunk (6 fibres), and only one had its RF in the tail. Almost half of the forelimb units (69 fibres) were fired by stimulation of the most proximal parts of the forelimb and of the shoulder; about one third (57 fibres) exhibited RFs located in the forepaw; the remaining units (20 fibres) had their RFs in the intermediate region of the forelimb. Neither the trigeminal nor segmental RFs ever extended across the midline. The distribution of the fibres within the CC conformed to a somatotopic pattern. The representations of the trigeminal and segmental regions were largely coextensive. Along the rostro-caudal axis of the CC, units with RFs in the mandibular, maxillar and ophthalmic divisions of the trigeminal region tended to lie in this order in the rostralmost 4 mm. Segmental representation extended over the rostralmost 6 mm. Shoulder fibres were mainly found in the rostral half, whereas forepaw units were segregated in the caudal half.