Biopolitics: the newest synthesis?

On first impression, the disciplines of genetics and political science would appear to be unrelated. And yet, commencing more than 30 years ago, the interdisciplinary field known as Biopolitics has now taken hold. This essay traces the central thrust of the biopolitical research agenda. It describes, analyzes, and assesses how political scientists have sought to show connections between our species' genetic constitution and our species' political behavior. Important bridges between the two are the neurophysiology of the human brain and the role of evolutionary theory in charting man's adaptational political profile. The parameters of the emerging biopolitical literature raise profound policy questions, some of which are also characterized. This revised version was published online in August 2006 with corrections to the Cover Date.     

Normative nerve conductions in the tail of rhesus macaques (Macaca mulatta)

BACKGROUND: The aim of this study was to test the feasibility of using the tail of Macaca mulatta for neurophysiological testing of the peripheral nervous system. METHODS: Motor and sensory nerve conduction studies (NCS) of the tail were obtained by surface stimulation and recording. The technique utilized was novel. Unlike other NCS obtained from other peripheral nerves, this technique did not require any special neurophysiological expertise. RESULTS: The latency of the motor and sensory response was 2.5 +/- 0.71 and 1.1 +/- 0.27 ms respectively. The amplitude of the motor and sensory response was 8.1 +/- 5.1 mV and 14.6 +/- 9.4 microV respectively. Similar to human beings, there was a statistically significant relationship between age and motor amplitude, motor latency and sensory latency. CONCLUSIONS: Based on our results, a relatively simple, reproducible neurophysiological monitoring technique of the peripheral nervous system is possible.     

Masking effect of different durations of forward masker sound on acoustical responses of mouse inferior collicular neurons to probe sound

To study the effects of different durations of forward masker sound on neuronal firing and rate-intensity function (RIF) of mouse inferior collicular (IC) neurons, a tone relative to 5 dB above the minimum threshold (re MT+5 dB) of the best frequency of recorded neurons was used as forward masker sound under free field stimulation condition. The masker durations used were 40, 60, 80, and 100 ms. Results showed that as masker duration was increased, inhibition in neuronal firing was enhanced (P < 0.000 1, n = 41) and the latency of neurons was lengthened (P<0.01, n = 41). In addition, among 41 inhibited IC neurons, 90.2% (37/41) exhibited narrowed dynamic range (DR) when masker sound duration was increased (P < 0.000 1), whereas the DR of 9.8%(4/41) became wider. These data suggest that masking effects of different durations of forward masker sound might be correlated with the amplitude and duration of inhibitory input to IC neurons elicited by the masker sound. __________ Translated from Journal of Central China Normal University (Nat. Sci.), 2005, 39(2): 236–240 [译自: 华中师范大学学报 (自然科学版), 2005, 39(2): 236–240]     

Advances in endophenotyping schizophrenia

The search for the genetic architecture of schizophrenia has employed multiple, often converging strategies. One such strategy entails the use of tracing the heritability and neurobiology of endophenotypes. Endophenotypes are quantifiable traits not visible to the eye, which are thought to reflect an intermediate place on the path from genes to disorder. Endophenotype abnormalities in domains such as neurophysiology or neurocognition occur in schizophrenia patients as well as their clinically “unaffected” relatives, and reflect polymorphisms in the DNA of schizophrenia spectrum subjects which create vulnerability to developing schizophrenia. By identifying the single nucleotide polymorphisms (SNPs) associated with endophenotypes in schizophrenia, psychiatric neuroscientists can select new strong inference based molecular targets for the treatment of schizophrenia.     

Toxicity and neurophysiological effects of fipronil and fipronil sulfone on the western corn rootworm (Coleoptera: Chrysomelidae)

Fipronil is a member of the relatively new phenylpyrazole insecticide class that is active at the neuro‐inhibitory gamma amino butyric acid (GABA)‐gated chloride channel/ionopore complex. The toxicity and neurophysiological effects of fipronil and its oxidative sulfone metabolite [5‐amino‐1‐(2,6‐dichloro‐4‐trifluoromethylphenyl)‐3‐cyano‐4‐trifluoromethylsulfonylpyrazole] were investigated by using an insecticide‐susceptible western corn rootworm population. In topical bioassays using adult rootworms, fipronil was toxic at very low doses (LD₅₀ = 0.07; LD₉₀ = 0.33 ng/mg). At the LD₉₀, pre‐treatment with the cytochrome P450 monooxygenase inhibitor piperonyl butoxide led to mild antagonism of fipronil toxicity (LD₉₀ = 0.42 ng/mg), while the sulfone analog had greater toxicity (LD₉₀ = 0.22 ng/mg). In neurophysiological studies of spontaneous electrical activity, adult and larval rootworms were equally affected by fipronil and the sulfone analog at 10 μM (in the presence of 5 mM GABA) in comparison to GABA‐treated baselines. Using larval rootworms, insensitivity of the GABA receptor to binding by picrotoxinin or dieldrin (10 μM ) was not apparent in the presence of 5 mM GABA. Further neurophysiological investigation using a range of concentrations (0.625–20.0 μM) on larval rootworms indicated concentration‐dependent effects on bursting activity for both fipronil and the sulfone analog; however, subtle differences were observed between these two compounds. Results indicate that both fipronil and its oxidative sulfone metabolite have similar toxicological and neurological effects on rootworms. Arch. Insect Biochem. Physiol. 40:150–156, 1999. © 1999 Wiley‐Liss, Inc.     

Listening to the environment: hearing differences from an epigenetic effect in solitarious and gregarious locusts

Locusts display a striking form of phenotypic plasticity, developing into either a lone-living solitarious phase or a swarming gregarious phase depending on population density. The two phases differ extensively in appearance, behaviour and physiology. We found that solitarious and gregarious locusts have clear differences in their hearing, both in their tympanal and neuronal responses. We identified significant differences in the shape of the tympana that may be responsible for the variations in hearing between locust phases. We measured the nanometre mechanical responses of the ear''s tympanal membrane to sound, finding that solitarious animals exhibit greater displacement. Finally, neural experiments signified that solitarious locusts have a relatively stronger response to high frequencies. The enhanced response to high-frequency sounds in the nocturnally flying solitarious locusts suggests greater investment in detecting the ultrasonic echolocation calls of bats, to which they are more vulnerable than diurnally active gregarious locusts. This study highlights the importance of epigenetic effects set forth during development and begins to identify how animals are equipped to match their immediate environmental needs.     

Refocusing the Neurocognitive Approach to Dreams: A Critique of the Hobson Versus Solms Debate.

This article examines the ongoing debate between activation-synthesis theorist J. Allan Hobson and psychoanalytic theorist Mark Solms about the nature of dreaming and dream content. After discussing their neurophysiological disagreements, it argues that they are more similar than different in some important ways, especially in talking about dreams in the same breath as psychosis and in drawing conclusions about dream content on the basis of their neurophysiological assumptions, without any reference to the systematic findings on the issue. Evidence from inside and outside the sleep laboratory on the coherent nature of most dreams is presented to demonstrate that neither theorist is on solid ground in his main assertions. Dreaming is usually a far more realistic and understandable enactment of interests and concerns than the 2 researchers assume. In addition, several of Hobson's and Solms's claims concerning the neural basis of dreaming are challenged on the basis of neurophysiological evidence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibitory effect of genital photoreceptors on the activity of abdominal motoneurones in Papilio xuthus (Lepidoptera,Papilionidae)

The inhibitory effect of butterfly genital photoreceptors on the activities of abdominal motoneurones is described. In two (N1, N3) of the six lateral nerves (N1–6) belonging to the last abdominal ganglion, spontaneous motoneurone activity was inhibited by illumination of the genital photoreceptors. N1 and N3 innervate the ventral longitudinal muscles. N2 and N4, which supply branches to the spiracular muscles, were not inhibited. The results allow some of the properties of the circuits in the abdominal nervous system supplied by the genital photoreceptors to be inferred. Some possible functions of the photoreceptors are discussed.     

Membrane Potentials,Synaptic Responses,Neuronal Circuitry,Neuromodulation and Muscle Histology Using the Crayfish: Student Laboratory Exercises

The purpose of this report is to help develop an understanding of the effects caused by ion gradients across a biological membrane. Two aspects that influence a cell''s membrane potential and which we address in these experiments are: (1) Ion concentration of K⁺ on the outside of the membrane, and (2) the permeability of the membrane to specific ions. The crayfish abdominal extensor muscles are in groupings with some being tonic (slow) and others phasic (fast) in their biochemical and physiological phenotypes, as well as in their structure; the motor neurons that innervate these muscles are correspondingly different in functional characteristics. We use these muscles as well as the superficial, tonic abdominal flexor muscle to demonstrate properties in synaptic transmission. In addition, we introduce a sensory-CNS-motor neuron-muscle circuit to demonstrate the effect of cuticular sensory stimulation as well as the influence of neuromodulators on certain aspects of the circuit. With the techniques obtained in this exercise, one can begin to answer many questions remaining in other experimental preparations as well as in physiological applications related to medicine and health. We have demonstrated the usefulness of model invertebrate preparations to address fundamental questions pertinent to all animals.     

Hypocalcemia-Induced Seizure: Demystifying the Calcium Paradox

Calcium is essential for both neurotransmitter release and muscle contraction. Given these important physiological processes, it seems reasonable to assume that hypocalcemia may lead to reduced neuromuscular excitability. Counterintuitively, however, clinical observation has frequently documented hypocalcemia’s role in induction of seizures and general excitability processes such as tetany, Chvostek’s sign, and bronchospasm. The mechanism of this calcium paradox remains elusive, and very few pathophysiological studies have addressed this conundrum. Nevertheless, several studies primarily addressing other biophysical issues have provided some clues. In this review, we analyze the data of these studies and propose an integrative model to explain this hypocalcemic paradox.