In this review, I explore the effects of both social organization and the physical environment, s... more In this review, I explore the effects of both social organization and the physical environment, specifically habitat complexity, on the brains and behavior of highly visual African cichlid fishes, drawing on examples from primates and birds where appropriate. In closely related fishes from the monophyletic Ectodinii clade of Lake Tanganyika, both forces influence cichlid brains and behavior. Considering social influences first, visual acuity differs with respect to social organization (monogamy versus polygyny). Both the telencephalon and amygdalar homologue, area Dm, are larger in monogamous species. Monogamous species are found to have more vasotocin-immunoreactive cells in the preoptic area of the brain. Habitat complexity also influences brain and behavior in these fishes. Total brain size, telencephalic and cerebellar size are positively correlated with habitat complexity. Visual acuity and spatial memory are enhanced in cichlids living in more complex environments. However habitat complexity and social forces affect cichlid brains differently. Taken together, our field data and plasticity data suggest that some of the species-specific neural effects of habitat complexity could be the consequence of the corresponding social correlates. Environmental forces, however, exert a broader effect on brain structures than social ones do, suggesting allometric expansion of the brain structures in concert with brain size and/or co-evolution of these structures [Current Zoology 56 (1): 144-156 2010].
Behavioral theories, insights, and techniques are too frequently ignored by conservation biologis... more Behavioral theories, insights, and techniques are too frequently ignored by conservation biologists. Yet an animal's survival and reproductive success clearly depend on its behavior. Using examples from marine, freshwater, and terrestrial realms, I assert that behavioral information is invaluable in five conservation areas: (1) managing wild species (e.g., designing marine reserves; reducing animal-human conflicts; understanding and managing species' responses to human-induced environmental stress such as fishing, introduced species, and chemical, visual, and acoustic pollution); (2) actively reversing the decline of imperiled wild species (e.g., reducing bycatch by improving selectivity of fishing gear; re-establishing breeding populations and boosting reproduction); (3) assessing biodiversity (e.g., modeling population viability; censusing and monitoring populations and species); (4) captive breeding and reintroduction programs (e.g., minimizing loss of valuable phenotypes; teaching or maintaining valuable survival skills); and (5) changing human behavior in resource exploitation (e.g., using principles from social psychology). Both realized and potential applications to fishes are stressed. Finally, behavioral diversity, a valuable but neglected element of biodiversity, needs to be explicitly conserved to maintain diverse populations. Arguments are presented that the conservation of species diversity and genetic diversity alone does not necessarily protect important behavioral diversity. The maintenance of both individual and population variability may be essential for the preservation of a species.
ship with habitat measures. Brain size and cerebellar size are positively correlated with species... more ship with habitat measures. Brain size and cerebellar size are positively correlated with species number (which is correlated with habitat complexity); the medulla and olfactory bulb are negatively correlated with habitat measures. The telencephalon shows a trend toward a positive correlation with rock size. In contrast, only two brain structures, the telencephalon and hypothalamus, are correlated with social factors. Telencephalic size is larger in monogamous species compared to polygamous species, as well as with increased numbers of individuals; monogamy is also associated with smaller hypothalamic size. Our results suggest that selection or drift can act independently on different brain regions as the species diverge into different habitats and social systems.
Our long-term goal is to understand the relationship between complex behaviors and complex brains... more Our long-term goal is to understand the relationship between complex behaviors and complex brains. Here, we explore the effects of social organization, specifically monogamy versus polygamy, on the brains and behavior of African cichlid fishes. Since cichlids process social information visually, we began by behaviorally comparing the visual acuity of monogamous and polygamous fish. We then explored the next level, where social meaning is extracted from the sensory information, by comparing the size of the telencephalon and amygdalar homologue, area Dm. We also explored integrative brain areas and neuropeptides implicated in social behavior by comparing the number of AVT-immunoreactive cells in the preoptic area of the brain. Finally, we explored the role of social experience in visual behavior in a monogamous species by comparing isolated fish with those from a normal social group. This paper details the preliminary results of our investigation.
Our previous studies demonstrated that fractured tactile cerebellar maps in rats reorganize follo... more Our previous studies demonstrated that fractured tactile cerebellar maps in rats reorganize following deafferentation during development and in adulthood, while maintaining a fractured somatotopy (Gonzalez et al. 1993; Morissette 1996; Shumway et al. 1999). Several months after deafferentation of the infraorbital branch of the trigeminal nerve, the missing upper lip innervation is replaced in the tactile maps in the granule cell layer of crus IIa. The predominant input into the denervated area is always the upper incisor representation. This study examined whether this reorganization was due to mechanisms intrinsic to the cerebellum or extrinsic, i.e., occurring in somatosensory structures afferent to the cerebellum. We first compared normal and deafferented maps, and found that the expansion of the upper incisor is not due to a preexisting bias in the strength or abundance of upper incisor input in normal animals. We then mapped tactile representations before and immediately after ...
Behavioral theories, insights, and techniques are too frequently ignored by conservation biologis... more Behavioral theories, insights, and techniques are too frequently ignored by conservation biologists. Yet an animal's survival and reproductive success clearly depend on its behavior. Using examples from marine, freshwater, and terrestrial realms, I assert that behavioral information is invaluable in five conservation areas: (1) managing wild species (e.g., designing marine reserves; reducing animal-human conflicts; understanding and managing species' responses to human-induced environmental stress such as fishing, introduced species, and chemical, visual, and acoustic pollution); (2) actively reversing the decline of imperiled wild species (e.g., reducing bycatch by improving selectivity of fishing gear; re-establishing breeding populations and boosting reproduction); (3) assessing biodiversity (e.g., modeling population viability; censusing and monitoring populations and species); (4) captive breeding and reintroduction programs (e.g., minimizing loss of valuable phenotypes; teaching or maintaining valuable survival skills); and (5) changing human behavior in resource exploitation (e.g., using principles from social psychology). Both realized and potential applications to fishes are stressed. Finally, behavioral diversity, a valuable but neglected element of biodiversity, needs to be explicitly conserved to maintain diverse populations. Arguments are presented that the conservation of species diversity and genetic diversity alone does not necessarily protect important behavioral diversity. The maintenance of both individual and population variability may be essential for the preservation of a species.
In this review, I explore the effects of both social organization and the physical environment, s... more In this review, I explore the effects of both social organization and the physical environment, specifically habitat complexity, on the brains and behavior of highly visual African cichlid fishes, drawing on examples from primates and birds where appropriate. In closely related fishes from the monophyletic Ectodinii clade of Lake Tanganyika, both forces influence cichlid brains and behavior. Considering social influences first, visual acuity differs with respect to social organization (monogamy versus polygyny). Both the telencephalon and amygdalar homologue, area Dm, are larger in monogamous species. Monogamous species are found to have more vasotocin-immunoreactive cells in the preoptic area of the brain. Habitat complexity also influences brain and behavior in these fishes. Total brain size, telencephalic and cerebellar size are positively correlated with habitat complexity. Visual acuity and spatial memory are enhanced in cichlids living in more complex environments. However hab...
1. Hypopomus occidentalis, a weakly electric gymnotiform fish with a pulse-type discharge, has a ... more 1. Hypopomus occidentalis, a weakly electric gymnotiform fish with a pulse-type discharge, has a sexually dimorphic electric organ discharge (Hagedorn 1983). The electric organ discharges (EODs) of males in the breeding season are longer in duration and have a lower peakpower frequency than the EODs of females. We tested reproductively mature fish in the field by presenting electronically generated stimuli in which the only cue for sex recognition was the waveshape of individual EOD-like pulses in a train. We found that gravid females could readily discriminate male-like from female-like EOD waveshapes, and we conclude that this feature of the electric signal is sufficient for sex recognition. 2. To understand the possible neural bases for discrimination of male and female EODs by H. occidentalis, we conducted a neurophysiological examination of both peripheral and central neurons. Our studies show that there are sets of neurons in this species which can discriminate male or female EODs by coding either temporal or spectral features of the EOD. 3. Temporal encoding of stimulus duration was observed in evoked field potential recordings from the magnocellular nucleus of the midbrain torus semicircularis. This nucleus indirectly receives pulse marker electroreceptor information. The field potentials suggest that comparison is possible between pulse marker activity on opposite sides of the body. 4. From standard frequency-threshold curves, spectral encoding of stimulus peak-power frequency was measured in burst duration coder electroreceptor afferents. In both male and female fish, the best frequencies of the narrow-band popula-Abbreviation: EOD electric organ discharge * To whom offprint requests should be sent
Ecosystem-based management requires greater attention to habitat conservation. We evaluate the im... more Ecosystem-based management requires greater attention to habitat conservation. We evaluate the importance of benthic habitats as space for shelter, feeding, and breeding by coastal fishes and motile invertebrates in four biogeographic regions of the eastern United States. The importance of different habitats changed with latitude. Soft sediments and riverine systems scored higher in northern regions, and marshes and coral reefs scored higher in the south. The importance of soft sediments is notable because environmental assessments often assume their ecological value is lower. Submerged aquatic vegetation was a key nursery habitat coast-wide. An important consideration is that anthropogenic impacts have altered habitat availability and use, and climate change is causing ongoing disturbance. Furthermore, distinct habitats should not be managed in isolation but rather as interconnected mosaics. Our approach, combined with information on status, vulnerability, and other ecological functions, can be used to evaluate trade-offs and develop habitat-management strategies.
1. Many aquatic studies have attempted to relate biological features, such as species diversity, ... more 1. Many aquatic studies have attempted to relate biological features, such as species diversity, abundance, brain size and behaviour, to measures of habitat complexity. Previous measures of habitat complexity have ranged from simple, habitat-specific variables, such as the number of twigs in a stream, to quantitative parameters of surface topography, such as rugosity. 2. We present a new video-based technique, called optical intensity, for assaying habitat complexity in aquatic ecosystems. Optical intensity is a visual, quantitative technique modifiable for any scale or for a nested analysis. We field-tested the technique in Lake Tanganyika, Tanzania, on 38 quadrats (5 • 5 m) to determine if three freshwater habitats (sand, rock and intermediate) were quantitatively different. 3. A comparison of the values obtained from optical intensity with a previous measure of surface topography (rugosity) showed that the two corresponded well and revealed clear differences among habitats. Both the new measure and rugosity were positively correlated with species diversity, species richness and abundance. Finally, whether used alone or in combination, both measures had predictive value for fish community parameters. 4. This new measure should prove useful to researchers exploring habitat complexity in both marine and freshwater systems.
The Journal of neuroscience : the official journal of the Society for Neuroscience, 1989
Both wave- and pulse-type species of weakly electric gymnotiform fish have 3 topographic maps of ... more Both wave- and pulse-type species of weakly electric gymnotiform fish have 3 topographic maps of electroreceptive information in the electrosensory lateral line lobe (ELL). These maps receive identical input from trifurcating axons of phase- and amplitude-coding primary afferents (Carr et al., 1982; Heiligenberg and Dye, 1982). Physiological experiments in the ELL of the wave-type fish Eigenmannia show that the amplitude-coding pyramidal cells differ among maps with respect to receptive field size, sensitivity, rate of adaptation, and temporal-frequency response (Shumway, 1989). This study investigated morphological correlates of the physiological differences among maps. Estimates of primary afferent convergence in Eigenmannia, based on map size, cell counts, and areas of terminal fields from intracellularly filled P-type primary afferents, suggest a 2-fold increase in convergence in the lateral map relative to the centromedial map. Similar differences in convergence between maps ar...
More complex brains and behaviors have arisen repeatedly throughout both vertebrate and invertebr... more More complex brains and behaviors have arisen repeatedly throughout both vertebrate and invertebrate evolution. The challenge is to tease apart the forces underlying such change. In this review, I show how habitat complexity influences both brain and behavior in African cichlid fishes, drawing on examples from primates and birds where appropriate. These species groups share a number of similarities. They exhibit a considerable range of brain to body weight within their group. Often highly visual, the species show a diversity of habitat types, social systems, and cognitive abilities. Phylogenies are well established. In closely-related cichlid fishes from the monophyletic Ectodine clade of Lake Tanganyika, habitat complexity is directly correlated with social variables, including species richness, diversity, and abundance. Total brain size, telencephalic and cerebellar size are positively correlated with habitat complexity. Visual acuity and spatial memory are also enhanced in cichlids living in more complex environments. I speculate that species-specific neural effects of environmental complexity could be the consequence of the corresponding social changes. However, environmental and social forces affect brains differently. Environmental forces exert a broader effect on brain structures than social ones, suggesting either allometric expansion of the brain structures in concert with brain size and/or co-evolution of these structures. To advance our understanding of the mechanism by which habitat complexity affects brain and behavior will require the use of closely-related species, quantification of complexity, hypothesis testing restricting analysis to a single variable and path analyses to explore the order of importance of such variables. We will also need new experimental paradigms exploring the cognitive and survival value of brain and brain structure changes both in the laboratory and in the wild.
The authors studied the effects of habitat complexity and social organization on visual acuity in... more The authors studied the effects of habitat complexity and social organization on visual acuity in closely related cichlid fishes (the Ectodini clade). The authors quantified habitat complexity among sand, intermediate, and rock habitats using chromatic difference measures (intensity analysis). Visual acuity was measured behaviorally, using optomotor/optokinetic responses to rotating square-wave stimuli. The rock-dwelling Asprotilapia leptura exhibited the best visual ability, compared with the intermediate and sand-dwelling species, Xenotilapia spilotera and Xenotilapia flavipinnis. The authors then compared effects of social organization. The lek-forming, polygamous Enantiopus melanogenys showed better visual acuity than that of the pair-bonding, monogamous X. flavipinnis. The authors' results are the first to demonstrate that species-specific differences in visual acuity are associated with differences in both the physical and social environment.
Discussion took place regarding what particular action was being sought from the Planning Board a... more Discussion took place regarding what particular action was being sought from the Planning Board about the Branch Village Revitalization Plan. It was understood that state statute calls for an opinion by the Planning Board when the Town Council considers land-use related ordinances and plans. The proposed Branch Village Revitalization Plan is now at the concept stage and does not yet
Altman J. Postnatal development of the cerebellar cortex in the rat. III. Maturation of the compo... more Altman J. Postnatal development of the cerebellar cortex in the rat. III. Maturation of the components of the granular layer. J Comp Neurol 145: 465-514, 1972. Arsénio-Nunes ML and Sotelo C. Development of the spinocerebellar system in the postnatal rat. J Comp Neurol 237: 265-271, 1985. Arsénio-Nunes ML, Sotelo C, and Wehrlé R. Organization of spinocerebellar projection map in three types of agranular cerebellum: Purkinje cells vs. granule cells as organizer elements. J Comp Neurol 273: 120 -136, 1988. Barbay S, Peden EK, Falchook G, and Nudo RJ. Sensitivity of neurons in somatosensory cortex (S1) to cutaneous stimulation of the hindlimb immediately following a sciatic nerve crush. Somatosens Mot Res 10: 103-114, 1999. Bower JM. The cerebellum and the control of sensory data aquisition. In: The Cerebellum and Cognition, edited by Schmahmann J. San Diego: Academic Press, 1997a, p. 489 -513. Bower JM. Is the cerebellum sensory for motor's sake, or motor for sensory's sake? The view from the whiskers of a rat. Prog Brain Res 114: 483-516, 1997b. Bower JM. The functional organization of cerebellar circuitry reconsidered. In: The Cerebellum: Recent Developments in Cerebellar Research, edited by sensory cortex of adult mammals: possible relationship to perceptual learning. Clin Exp Pharmacol Physiol 23: 939 -947, 1996. Jain N, Florence SL, Qi H-X, and Kaas JH. Growth of new brainstem connections in adult monkeys with massive sensory loss. Proc Natl Acad Sci USA 97: 5546 -5550, 2000. Jain N, Qi H-X, Catania KC, and Kaas JH. Anatomic correlates of the face and oral cavity representations in the somatosensory cortical area 3b of monkeys. J Comp Neurol 429: 455-468, 2001. Ji Z and Hawkes R. Developing mossy fiber terminal fields in the rat cerebellar cortex may segregate because of Purkinje cell compartmentation and not competition. J Comp Neurol 259: 197-212, 1995. Jones EG. Cortical and subcortical contributions to activity-dependent plasticity in primate somatosensory cortex. Annu Rev Neurosci 23: 1-37, 2000. Jones EG and Pons TP. Thalamic and brainstem contributions to large-scale plasticity of primate somatosensory cortex. Science 282: 1121-1125, 1998. Kaas JH. Plasticity of sensory and motor maps in adult mammals. Annu Rev Kaas JH, Florence SL, and Jain N. Subcortical contributions to massive cortical reorganizations. Neuron 22: 657-660, 1999. Kadish I and Van Groen T. Differences in lesion-induced hippocampal plasticity between mice and rats.
Abbreviations: ELL electrosensory lateral line lobe; EOD electric organ discharge; NPd dorsal nuc... more Abbreviations: ELL electrosensory lateral line lobe; EOD electric organ discharge; NPd dorsal nucleus praeeminentialis; EGP eminenfia granularis posterior round increased in spatial extent by 175% with bicuculline administration. Neither the size of the I unit receptive-field center nor the response magnitude changed in the presence of bicuculline. The antagonistic surround of I units, however, increased by 49%.
In this review, I explore the effects of both social organization and the physical environment, s... more In this review, I explore the effects of both social organization and the physical environment, specifically habitat complexity, on the brains and behavior of highly visual African cichlid fishes, drawing on examples from primates and birds where appropriate. In closely related fishes from the monophyletic Ectodinii clade of Lake Tanganyika, both forces influence cichlid brains and behavior. Considering social influences first, visual acuity differs with respect to social organization (monogamy versus polygyny). Both the telencephalon and amygdalar homologue, area Dm, are larger in monogamous species. Monogamous species are found to have more vasotocin-immunoreactive cells in the preoptic area of the brain. Habitat complexity also influences brain and behavior in these fishes. Total brain size, telencephalic and cerebellar size are positively correlated with habitat complexity. Visual acuity and spatial memory are enhanced in cichlids living in more complex environments. However habitat complexity and social forces affect cichlid brains differently. Taken together, our field data and plasticity data suggest that some of the species-specific neural effects of habitat complexity could be the consequence of the corresponding social correlates. Environmental forces, however, exert a broader effect on brain structures than social ones do, suggesting allometric expansion of the brain structures in concert with brain size and/or co-evolution of these structures [Current Zoology 56 (1): 144-156 2010].
Behavioral theories, insights, and techniques are too frequently ignored by conservation biologis... more Behavioral theories, insights, and techniques are too frequently ignored by conservation biologists. Yet an animal's survival and reproductive success clearly depend on its behavior. Using examples from marine, freshwater, and terrestrial realms, I assert that behavioral information is invaluable in five conservation areas: (1) managing wild species (e.g., designing marine reserves; reducing animal-human conflicts; understanding and managing species' responses to human-induced environmental stress such as fishing, introduced species, and chemical, visual, and acoustic pollution); (2) actively reversing the decline of imperiled wild species (e.g., reducing bycatch by improving selectivity of fishing gear; re-establishing breeding populations and boosting reproduction); (3) assessing biodiversity (e.g., modeling population viability; censusing and monitoring populations and species); (4) captive breeding and reintroduction programs (e.g., minimizing loss of valuable phenotypes; teaching or maintaining valuable survival skills); and (5) changing human behavior in resource exploitation (e.g., using principles from social psychology). Both realized and potential applications to fishes are stressed. Finally, behavioral diversity, a valuable but neglected element of biodiversity, needs to be explicitly conserved to maintain diverse populations. Arguments are presented that the conservation of species diversity and genetic diversity alone does not necessarily protect important behavioral diversity. The maintenance of both individual and population variability may be essential for the preservation of a species.
ship with habitat measures. Brain size and cerebellar size are positively correlated with species... more ship with habitat measures. Brain size and cerebellar size are positively correlated with species number (which is correlated with habitat complexity); the medulla and olfactory bulb are negatively correlated with habitat measures. The telencephalon shows a trend toward a positive correlation with rock size. In contrast, only two brain structures, the telencephalon and hypothalamus, are correlated with social factors. Telencephalic size is larger in monogamous species compared to polygamous species, as well as with increased numbers of individuals; monogamy is also associated with smaller hypothalamic size. Our results suggest that selection or drift can act independently on different brain regions as the species diverge into different habitats and social systems.
Our long-term goal is to understand the relationship between complex behaviors and complex brains... more Our long-term goal is to understand the relationship between complex behaviors and complex brains. Here, we explore the effects of social organization, specifically monogamy versus polygamy, on the brains and behavior of African cichlid fishes. Since cichlids process social information visually, we began by behaviorally comparing the visual acuity of monogamous and polygamous fish. We then explored the next level, where social meaning is extracted from the sensory information, by comparing the size of the telencephalon and amygdalar homologue, area Dm. We also explored integrative brain areas and neuropeptides implicated in social behavior by comparing the number of AVT-immunoreactive cells in the preoptic area of the brain. Finally, we explored the role of social experience in visual behavior in a monogamous species by comparing isolated fish with those from a normal social group. This paper details the preliminary results of our investigation.
Our previous studies demonstrated that fractured tactile cerebellar maps in rats reorganize follo... more Our previous studies demonstrated that fractured tactile cerebellar maps in rats reorganize following deafferentation during development and in adulthood, while maintaining a fractured somatotopy (Gonzalez et al. 1993; Morissette 1996; Shumway et al. 1999). Several months after deafferentation of the infraorbital branch of the trigeminal nerve, the missing upper lip innervation is replaced in the tactile maps in the granule cell layer of crus IIa. The predominant input into the denervated area is always the upper incisor representation. This study examined whether this reorganization was due to mechanisms intrinsic to the cerebellum or extrinsic, i.e., occurring in somatosensory structures afferent to the cerebellum. We first compared normal and deafferented maps, and found that the expansion of the upper incisor is not due to a preexisting bias in the strength or abundance of upper incisor input in normal animals. We then mapped tactile representations before and immediately after ...
Behavioral theories, insights, and techniques are too frequently ignored by conservation biologis... more Behavioral theories, insights, and techniques are too frequently ignored by conservation biologists. Yet an animal's survival and reproductive success clearly depend on its behavior. Using examples from marine, freshwater, and terrestrial realms, I assert that behavioral information is invaluable in five conservation areas: (1) managing wild species (e.g., designing marine reserves; reducing animal-human conflicts; understanding and managing species' responses to human-induced environmental stress such as fishing, introduced species, and chemical, visual, and acoustic pollution); (2) actively reversing the decline of imperiled wild species (e.g., reducing bycatch by improving selectivity of fishing gear; re-establishing breeding populations and boosting reproduction); (3) assessing biodiversity (e.g., modeling population viability; censusing and monitoring populations and species); (4) captive breeding and reintroduction programs (e.g., minimizing loss of valuable phenotypes; teaching or maintaining valuable survival skills); and (5) changing human behavior in resource exploitation (e.g., using principles from social psychology). Both realized and potential applications to fishes are stressed. Finally, behavioral diversity, a valuable but neglected element of biodiversity, needs to be explicitly conserved to maintain diverse populations. Arguments are presented that the conservation of species diversity and genetic diversity alone does not necessarily protect important behavioral diversity. The maintenance of both individual and population variability may be essential for the preservation of a species.
In this review, I explore the effects of both social organization and the physical environment, s... more In this review, I explore the effects of both social organization and the physical environment, specifically habitat complexity, on the brains and behavior of highly visual African cichlid fishes, drawing on examples from primates and birds where appropriate. In closely related fishes from the monophyletic Ectodinii clade of Lake Tanganyika, both forces influence cichlid brains and behavior. Considering social influences first, visual acuity differs with respect to social organization (monogamy versus polygyny). Both the telencephalon and amygdalar homologue, area Dm, are larger in monogamous species. Monogamous species are found to have more vasotocin-immunoreactive cells in the preoptic area of the brain. Habitat complexity also influences brain and behavior in these fishes. Total brain size, telencephalic and cerebellar size are positively correlated with habitat complexity. Visual acuity and spatial memory are enhanced in cichlids living in more complex environments. However hab...
1. Hypopomus occidentalis, a weakly electric gymnotiform fish with a pulse-type discharge, has a ... more 1. Hypopomus occidentalis, a weakly electric gymnotiform fish with a pulse-type discharge, has a sexually dimorphic electric organ discharge (Hagedorn 1983). The electric organ discharges (EODs) of males in the breeding season are longer in duration and have a lower peakpower frequency than the EODs of females. We tested reproductively mature fish in the field by presenting electronically generated stimuli in which the only cue for sex recognition was the waveshape of individual EOD-like pulses in a train. We found that gravid females could readily discriminate male-like from female-like EOD waveshapes, and we conclude that this feature of the electric signal is sufficient for sex recognition. 2. To understand the possible neural bases for discrimination of male and female EODs by H. occidentalis, we conducted a neurophysiological examination of both peripheral and central neurons. Our studies show that there are sets of neurons in this species which can discriminate male or female EODs by coding either temporal or spectral features of the EOD. 3. Temporal encoding of stimulus duration was observed in evoked field potential recordings from the magnocellular nucleus of the midbrain torus semicircularis. This nucleus indirectly receives pulse marker electroreceptor information. The field potentials suggest that comparison is possible between pulse marker activity on opposite sides of the body. 4. From standard frequency-threshold curves, spectral encoding of stimulus peak-power frequency was measured in burst duration coder electroreceptor afferents. In both male and female fish, the best frequencies of the narrow-band popula-Abbreviation: EOD electric organ discharge * To whom offprint requests should be sent
Ecosystem-based management requires greater attention to habitat conservation. We evaluate the im... more Ecosystem-based management requires greater attention to habitat conservation. We evaluate the importance of benthic habitats as space for shelter, feeding, and breeding by coastal fishes and motile invertebrates in four biogeographic regions of the eastern United States. The importance of different habitats changed with latitude. Soft sediments and riverine systems scored higher in northern regions, and marshes and coral reefs scored higher in the south. The importance of soft sediments is notable because environmental assessments often assume their ecological value is lower. Submerged aquatic vegetation was a key nursery habitat coast-wide. An important consideration is that anthropogenic impacts have altered habitat availability and use, and climate change is causing ongoing disturbance. Furthermore, distinct habitats should not be managed in isolation but rather as interconnected mosaics. Our approach, combined with information on status, vulnerability, and other ecological functions, can be used to evaluate trade-offs and develop habitat-management strategies.
1. Many aquatic studies have attempted to relate biological features, such as species diversity, ... more 1. Many aquatic studies have attempted to relate biological features, such as species diversity, abundance, brain size and behaviour, to measures of habitat complexity. Previous measures of habitat complexity have ranged from simple, habitat-specific variables, such as the number of twigs in a stream, to quantitative parameters of surface topography, such as rugosity. 2. We present a new video-based technique, called optical intensity, for assaying habitat complexity in aquatic ecosystems. Optical intensity is a visual, quantitative technique modifiable for any scale or for a nested analysis. We field-tested the technique in Lake Tanganyika, Tanzania, on 38 quadrats (5 • 5 m) to determine if three freshwater habitats (sand, rock and intermediate) were quantitatively different. 3. A comparison of the values obtained from optical intensity with a previous measure of surface topography (rugosity) showed that the two corresponded well and revealed clear differences among habitats. Both the new measure and rugosity were positively correlated with species diversity, species richness and abundance. Finally, whether used alone or in combination, both measures had predictive value for fish community parameters. 4. This new measure should prove useful to researchers exploring habitat complexity in both marine and freshwater systems.
The Journal of neuroscience : the official journal of the Society for Neuroscience, 1989
Both wave- and pulse-type species of weakly electric gymnotiform fish have 3 topographic maps of ... more Both wave- and pulse-type species of weakly electric gymnotiform fish have 3 topographic maps of electroreceptive information in the electrosensory lateral line lobe (ELL). These maps receive identical input from trifurcating axons of phase- and amplitude-coding primary afferents (Carr et al., 1982; Heiligenberg and Dye, 1982). Physiological experiments in the ELL of the wave-type fish Eigenmannia show that the amplitude-coding pyramidal cells differ among maps with respect to receptive field size, sensitivity, rate of adaptation, and temporal-frequency response (Shumway, 1989). This study investigated morphological correlates of the physiological differences among maps. Estimates of primary afferent convergence in Eigenmannia, based on map size, cell counts, and areas of terminal fields from intracellularly filled P-type primary afferents, suggest a 2-fold increase in convergence in the lateral map relative to the centromedial map. Similar differences in convergence between maps ar...
More complex brains and behaviors have arisen repeatedly throughout both vertebrate and invertebr... more More complex brains and behaviors have arisen repeatedly throughout both vertebrate and invertebrate evolution. The challenge is to tease apart the forces underlying such change. In this review, I show how habitat complexity influences both brain and behavior in African cichlid fishes, drawing on examples from primates and birds where appropriate. These species groups share a number of similarities. They exhibit a considerable range of brain to body weight within their group. Often highly visual, the species show a diversity of habitat types, social systems, and cognitive abilities. Phylogenies are well established. In closely-related cichlid fishes from the monophyletic Ectodine clade of Lake Tanganyika, habitat complexity is directly correlated with social variables, including species richness, diversity, and abundance. Total brain size, telencephalic and cerebellar size are positively correlated with habitat complexity. Visual acuity and spatial memory are also enhanced in cichlids living in more complex environments. I speculate that species-specific neural effects of environmental complexity could be the consequence of the corresponding social changes. However, environmental and social forces affect brains differently. Environmental forces exert a broader effect on brain structures than social ones, suggesting either allometric expansion of the brain structures in concert with brain size and/or co-evolution of these structures. To advance our understanding of the mechanism by which habitat complexity affects brain and behavior will require the use of closely-related species, quantification of complexity, hypothesis testing restricting analysis to a single variable and path analyses to explore the order of importance of such variables. We will also need new experimental paradigms exploring the cognitive and survival value of brain and brain structure changes both in the laboratory and in the wild.
The authors studied the effects of habitat complexity and social organization on visual acuity in... more The authors studied the effects of habitat complexity and social organization on visual acuity in closely related cichlid fishes (the Ectodini clade). The authors quantified habitat complexity among sand, intermediate, and rock habitats using chromatic difference measures (intensity analysis). Visual acuity was measured behaviorally, using optomotor/optokinetic responses to rotating square-wave stimuli. The rock-dwelling Asprotilapia leptura exhibited the best visual ability, compared with the intermediate and sand-dwelling species, Xenotilapia spilotera and Xenotilapia flavipinnis. The authors then compared effects of social organization. The lek-forming, polygamous Enantiopus melanogenys showed better visual acuity than that of the pair-bonding, monogamous X. flavipinnis. The authors' results are the first to demonstrate that species-specific differences in visual acuity are associated with differences in both the physical and social environment.
Discussion took place regarding what particular action was being sought from the Planning Board a... more Discussion took place regarding what particular action was being sought from the Planning Board about the Branch Village Revitalization Plan. It was understood that state statute calls for an opinion by the Planning Board when the Town Council considers land-use related ordinances and plans. The proposed Branch Village Revitalization Plan is now at the concept stage and does not yet
Altman J. Postnatal development of the cerebellar cortex in the rat. III. Maturation of the compo... more Altman J. Postnatal development of the cerebellar cortex in the rat. III. Maturation of the components of the granular layer. J Comp Neurol 145: 465-514, 1972. Arsénio-Nunes ML and Sotelo C. Development of the spinocerebellar system in the postnatal rat. J Comp Neurol 237: 265-271, 1985. Arsénio-Nunes ML, Sotelo C, and Wehrlé R. Organization of spinocerebellar projection map in three types of agranular cerebellum: Purkinje cells vs. granule cells as organizer elements. J Comp Neurol 273: 120 -136, 1988. Barbay S, Peden EK, Falchook G, and Nudo RJ. Sensitivity of neurons in somatosensory cortex (S1) to cutaneous stimulation of the hindlimb immediately following a sciatic nerve crush. Somatosens Mot Res 10: 103-114, 1999. Bower JM. The cerebellum and the control of sensory data aquisition. In: The Cerebellum and Cognition, edited by Schmahmann J. San Diego: Academic Press, 1997a, p. 489 -513. Bower JM. Is the cerebellum sensory for motor's sake, or motor for sensory's sake? The view from the whiskers of a rat. Prog Brain Res 114: 483-516, 1997b. Bower JM. The functional organization of cerebellar circuitry reconsidered. In: The Cerebellum: Recent Developments in Cerebellar Research, edited by sensory cortex of adult mammals: possible relationship to perceptual learning. Clin Exp Pharmacol Physiol 23: 939 -947, 1996. Jain N, Florence SL, Qi H-X, and Kaas JH. Growth of new brainstem connections in adult monkeys with massive sensory loss. Proc Natl Acad Sci USA 97: 5546 -5550, 2000. Jain N, Qi H-X, Catania KC, and Kaas JH. Anatomic correlates of the face and oral cavity representations in the somatosensory cortical area 3b of monkeys. J Comp Neurol 429: 455-468, 2001. Ji Z and Hawkes R. Developing mossy fiber terminal fields in the rat cerebellar cortex may segregate because of Purkinje cell compartmentation and not competition. J Comp Neurol 259: 197-212, 1995. Jones EG. Cortical and subcortical contributions to activity-dependent plasticity in primate somatosensory cortex. Annu Rev Neurosci 23: 1-37, 2000. Jones EG and Pons TP. Thalamic and brainstem contributions to large-scale plasticity of primate somatosensory cortex. Science 282: 1121-1125, 1998. Kaas JH. Plasticity of sensory and motor maps in adult mammals. Annu Rev Kaas JH, Florence SL, and Jain N. Subcortical contributions to massive cortical reorganizations. Neuron 22: 657-660, 1999. Kadish I and Van Groen T. Differences in lesion-induced hippocampal plasticity between mice and rats.
Abbreviations: ELL electrosensory lateral line lobe; EOD electric organ discharge; NPd dorsal nuc... more Abbreviations: ELL electrosensory lateral line lobe; EOD electric organ discharge; NPd dorsal nucleus praeeminentialis; EGP eminenfia granularis posterior round increased in spatial extent by 175% with bicuculline administration. Neither the size of the I unit receptive-field center nor the response magnitude changed in the presence of bicuculline. The antagonistic surround of I units, however, increased by 49%.
Uploads
Papers by Caroly Shumway