Birds Can “See” Earth’s Magnetic Field
BY John Roach  /  September 27, 2007

To find north, humans look to a compass. But birds may just need to open their eyes, a new study says. Scientists already suspected birds’ eyes contain molecules that are thought to sense Earth’s magnetic field. In a new study, German researchers found that these molecules are linked to an area of the brain known to process visual information. In that sense, “birds may see the magnetic field,” said study lead author Dominik Heyers, a biologist at the University of Oldenburg.

Magnetic Orientation
Human-made compasses work by using Earth as an enormous magnet and orienting a tiny magnet attached to a needle to the planet’s north and south poles. Scientists have thought for years that migratory birds may use an internal compass to navigate between their nesting areas and wintering grounds, which can be separated by thousands of miles. (Related news: “Migrating Birds Reset ‘Compasses’ at Sunset, Study Says” [April 15, 2004].) The new research helps explain how this natural compass may work.

Heyers and his colleagues injected migratory garden warblers with a special dye that can be traced as it travels along nerve fibers. The team put one type of tracer dye into the eyes and another in a region of the brain called Cluster N, which is most active when birds orient themselves. When the birds got their bearings, both tracers traveled to and met in the thalamus, a region in the middle of the brain responsible for vision. “That shows there is direct linkage between the eye and Cluster N,” Heyers said. The finding strongly supports the hypothesis that migratory birds use their visual system to navigate using the magnetic field. “The magnetic field or magnetic direction may be perceived as a dark or light spot which lies upon the normal visual field of the bird,” Heyers said, “and which, of course, changes when the bird turns its head.” The study was published in a recent issue of the Public Library of Science journal PLoS ONE.

More Navigational Tools
Scientists not involved with the study said it is impressive and well done, but cautioned that there are more pieces to the puzzle of how birds navigate on their long migrations. “An animal that has to migrate over great distances needs to have both a compass and a map,” said Cordula Mora, a biologist who recently completed her postdoctoral research at the University of North Carolina, Chapel Hill.

Mora’s work suggests that birds may use magnetic crystals in their beaks to sense the intensity of the magnetic field and thus glean information on their physical location. (Related news: “Magnetic Beaks Help Birds Navigate, Study Says” [November 24, 2004].) “If you have a compass, you know where north, south, east, [and] west [are], but you don’t know where you are, so you don’t know where you should be going,” she said. Study author Heyers said “both [map and compass] systems may act in concert.”

Robert Beason is a wildlife research biologist with the U.S. Department of Agriculture in Sandusky, Ohio, and an expert on bird navigation. He noted that stars may also either fully or in part provide the birds with their visual bearing—not the magnetic field. The next step is to figure out where all this information comes together in the bird brain, he noted. “That’s probably going to tell us where the navigation center for birds is,” he said.

Nature 432, 508-511 (25 November 2004) | doi:10.1038/nature03077;
Received 4 May 2004; Accepted 4 October 2004

Magnetoreception and its trigeminal mediation in the homing pigeon
Cordula V. Mora1,4, Michael Davison2, J. Martin Wild3 and Michael M. Walker1

Two conflicting hypotheses compete to explain how a homing pigeon can return to its loft over great distances. One proposes the use of atmospheric odours1 and the other the Earth’s magnetic field2, 3, 4 in the ‘map’ step of the ‘map and compass’ hypothesis of pigeon homing5. Although magnetic effects on pigeon orientation6, 7 provide indirect evidence for a magnetic ‘map’, numerous conditioning experiments8 have failed to demonstrate reproducible responses to magnetic fields by pigeons. This has led to suggestions that homing pigeons and other birds have no useful sensitivity to the Earth’s magnetic field9, 10, 11. Here we demonstrate that homing pigeons (Columba livia) can discriminate between the presence and absence of a magnetic anomaly in a conditioned choice experiment. This discrimination is impaired by attachment of a magnet to the cere, local anaesthesia of the upper beak area, and bilateral section of the ophthalmic branch of the trigeminal nerve, but not of the olfactory nerve. These results suggest that magnetoreception (probably magnetite-based) occurs in the upper beak area of the pigeon. Traditional methods of rendering pigeons anosmic might therefore cause simultaneous impairment of magnetoreception so that future orientation experiments will require independent evaluation of the pigeon’s magnetic and olfactory systems.

Cordula V. Mora
email: cvmora [at] email.unc [dot] edu

Dominik Heyers
email: dominik.heyers [at] uni-oldenburg [dot] de

Visual Pathway Links Brain Structures Active during
Magnetic Compass Orientation in Migratory Birds

Dominik Heyers1*, Martina Manns2, Harald Luksch3, Onur Güntürkün2, Henrik Mouritsen1 1 AG Neurosensorik, Institute of Biology, University of Oldenburg, Oldenburg, Germany, 2 Department of Biopsychology, Institute for Cognitive Neuroscience, Ruhr-University Bochum, Bochum, Germany, 3 Chair of Zoology, Department of Zoology, Technical University Munich, Freising-Weihenstephan, Germany

The magnetic compass of migratory birds has been suggested to be light-dependent. Retinal cryptochrome-expressing neurons and a forebrain region, “Cluster N”, show high neuronal activity when night-migratory songbirds perform magnetic compass orientation. By combining neuronal tracing with behavioral experiments leading to sensory-driven gene expression of the neuronal activity marker ZENK during magnetic compass orientation, we demonstrate a functional neuronal connection between the retinal neurons and Cluster N via the visual thalamus. Thus, the two areas of the central nervous system being most active during magnetic compass orientation are part of an ascending visual processing stream, the thalamofugal pathway. Furthermore, Cluster N seems to be a specialized part of the visual wulst. These findings strongly support the hypothesis that migratory birds use their visual system to perceive the reference compass direction of the geomagnetic field and that migratory birds “see” the reference compass direction provided by the geomagnetic field.

Citation: Heyers D, Manns M, Luksch H, Güntürkün O, Mouritsen H (2007) A Visual Pathway Links Brain Structures Active during Magnetic Compass Orientation in Migratory Birds. PLoS ONE 2(9): e937. doi:10.1371/ journal.pone.0000937 Academic Editor: Andrew Iwaniuk, University of Alberta, Canada Published: September 26, 2007 Copyright: © 2007 Heyers et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding: VolkswagenStiftung (“Dynamics and adaptivity of neuronal systems” grant given to D. Heyers and “Nachwuchsgruppe/Lichtenberg” grant given to H. Mouritsen), Deutsche Forschungsgemeinschaft (FOR 701 and MO 1408/1-2 grants to H. Mouritsen; Lu 622/8 grant to H. Luksch; SFB 509 to M. Manns and O. Güntürkün).

The navigational abilities of birds have fascinated mankind for centuries and challenged researchers for decades. Behavioral experiments have shown that night-migratory passerine birds can use a magnetic compass to orient during migration [e.g. 1], [2] and recent data suggest that the magnetic compass is used as the birds’ primary compass in mid-air during real migratory flights [3]. Nevertheless, the neuronal mechanisms underlying their magnetosensory abilities remain elusive.

Currently, theoretical, behavioral and physiological evidences support two magnetic sensing hypotheses: a magnetite-mediated magnetic sense [4]–[6] and/or a vision-mediated magnetic compass [7]. The magnetite-mediated mechanism seems to act as part of a magnetic map- or signpost sense, which could provide the animal with information about its geographic position, whereas the vision-mediated magnetic sense seems to be a pure compass sense that is based on radical-pair processes in the birds’ eye(s) [for reviews], [see e.g. 8, 9]. The light-dependent, radical-pair based, magnetic compass hypothesis suggests that magnetic modulations of radical-pair processes in photoreceptor molecules in the birds’ eyes provide information about the individual’s orientation relative to the magnetic field lines [7], [10].

Putative sensor molecules (cryptochromes) which seem to possess the required biophysical characteristics, have recently been shown to be expressed in the retina of migratory birds [11], [12]. In garden warblers, Sylvia borin, the cryptochrome-expressing retinal ganglion cells and a neuronal cluster located in posterolateral regions of both forebrain hemispheres (“Cluster N”) show high, sensory-driven neuronal activity as indicated by the expression of the Immediate Early Gene ZENK during magnetic orientation [12]–[14]. Strong neuronal activation in Cluster N is only observed at night in migratory birds but not in non-migratory zebra finches, and the activation in the migrants is absent when the birds’ eyes are covered, suggesting that some kind of night vision specialization in night-migratory birds is involved in activation of Cluster N. We have suggested [13] that night migratory birds may use Cluster N for seeing better at night and/or for visual night-time navigation. We furthermore suggested that Cluster N is likely to process such light-mediated magnetic compass responses, based on the fact that Cluster N is the only known forebrain area that is highly active during magnetic compass orientation, and on the theoretical model [7] on magnetic field modulation of the light sensitivity of specialized receptor molecules in the retina of the birds, [for detailed arguments see 13], [14].

Sensory systems process their particular stimuli in specific brain circuits and pathways. Thus, the identification of what sensory system(s) is active during magnetic compass orientation, provides a way to recognize the sensory quality utilized during that specific behavior. Therefore, the aim of the present study was to investigate whether and if so, how Cluster N and the retina are interconnected. To do this, we combined neuronal tracing with analyses of ZENK expression as a marker for neuronal activity induced during behavioral experiments.

By tracing retinal projections to the brain and simultaneously labeling connections innervating Cluster N, we found colocalization of the tracers in specific substructures of the visual thalamus. The anterograde (forward) tracing results of retinal projections in the garden warbler demonstrated virtually identical connections between the eye and the brain as known from other lateral-eyed bird species [e.g. 15]–[18]: fibers either projected onto the contralateral optic tectum (part of the tectofugal system), to the nucleus of the basal optic root (part of the accessory pathway) (data not shown) or curved into the thalamus innervating the dorsal geniculate complex.

The present data demonstrate an anatomical connection between the retina and Cluster N through the thalamus. This shows that Cluster N receives sensory input from the eyes and suggests that Cluster N is at least partly located in the visual Wulst. In general, the Wulst is the telencephalic termination area of the thalamofugal pathway which conveys visual input from the retina onto the forebrain via the Gld [18], [19]. We show here with retrograde tracing that Cluster N receives input from the Gld suggesting that at least parts of Cluster N belong to the visual wulst. More specifically, our focal tracer injections revealed that Cluster N is connected to a specific subsystem of the thalamofugal pathway. We could demonstrate that the projections from the thalamus upon the visual wulst in the garden warbler are organized in a topographic fashion as it was also shown in pigeons [20] and chicks [21]. This organization indicates that the thalamofugal system is structured into parallel, functionally segregated pathways which may process different aspects of visual stimuli [21], comparable to what is known from the tectofugal pathway [22], [23]. While Cluster N is innervated by latero-ventral Gld nuclei, portions of the visual wulst located medial from Cluster N receive input from dorso-medial thalamic neurons. These neuronal populations did not show as much overlap with retinal fibers as the ones projecting upon Cluster N. Thus, Cluster N is primarily connected to the thalamofugal subsystem that receives strong retinal input. This finding implies that visual information is the major input to Cluster N and supports the idea that magnetic compass orientation is linked to night vision.

The vast majority of forebrain neurons in songbirds can express ZENK as a marker for neuronal activity [13], [ 14], [ 24]–[26] Feenders, Liedvogel, Zapka, Mouritsen, Jarvis, personal communication]. Furthermore, movement-independent ZENK expression in the forebrain of night-migratory birds performing magnetic orientation at night is confined to Cluster N [with the strongest activation in distinct subregions (the shell surrounding the DNH nucleus)], as shown by the detailed quantification of ZENK expression within Cluster N performed in this study], and this expression massively decreased in corresponding brain areas of non-migratory songbirds and in all bird species during daytime [13]. Seen together, these findings strongly support the suggestion that Cluster N processes some kind of night-time visual information processing which is a specialization of night-migratory birds [for detailed arguments], [see 13, 14]. Combined with these findings, the present tracing data for the first time suggest a putative magnetosensory compass pathway from the sensory organ (the eye) to its main integrative brain center (Cluster N) in night-migratory birds. This putative compass-magnetosensory pathway involves restricted subregions at all levels of the thalamofugal visual pathway: neuronal subpopulations in the retina, ventral parts of the thalamic Gld (lateral and ventral DLL, SpRt, LdOPT) and lateral parts of the visual wulst (Cluster N). Due to the fact that a known visual pathway connects the only brain structures that have been shown to be active during magnetic orientation, our findings strongly support the hypothesis that migratory birds perceive the magnetic field as a visual pattern and that they are thus likely to “see” the magnetic field.

Materials and Methods
Animals and housing conditions
All animal procedures were approved by the local and national authorities for the use of animals in research. Adult garden warblers (Sylvia borin) were obtained from bird banding stations in Helgoland (Germany) and Rybachy (Russia). The birds were housed in single wire cages and experienced a circadian and circannual light regime closely matching the natural conditions in Oldenburg, Germany. All birds got used to captivity for at least 2 weeks before getting involved in any experiment. Food and water were provided ad libitum.

Axonal Tracing
A total of 21 birds were used in this study (see table 1). For tracer injections, birds were anaesthetized by intramuscular injection of ketamine (Pfitzer, Freiburg, Germany)/rompun (Bayer, Leverkusen, Germany), and their heads were fixed in a custom-built stereotactic apparatus. The skin on the birds’ head was anaesthetized using a surface anaesthetic (Xylocain; Astra Zeneca, Wedel, Germany) and incised dorsally. For tracer injections into the visual Wulst, application coordinates were determined relative to the prominent bifurcation of the Y-sinus [27] as an initial reference. A small part of the skull was carefully removed above the respective brain region. Afferents to the visual wulst were mapped by stereotactic iontophoretic application (4 µA positive current, 7 sec on/off, duration: 20–30 min) of biotinylated dextran amin (BDA, working dilution: 10% in phosphate buffered saline, PBS; Molecular Probes Europe BV, Leiden, The Netherlands) into Cluster N or into medial parts of the visual Wulst. After the surgery, the skin on the bird’s head was re-sealed with cyanoacrylate surgical glue (Glubran, Viareggio, Italy). Afterwards, anterograde connections from the retina were mapped by microinjection of 5 µl Choleratoxin B subunit (CtB, working dilution: 1% in distilled water; Sigma, Deissenhofen, Germany) in the vitreous of the eye contralateral to the Wulst injection.

Behavioral analysis
Forty-eight to seventy-two hours after surgery, single garden warblers were put into a custom-built, cylindrical plexiglass cage fitted with a circular perch in the center [28]. To allow acclimatization to the new surroundings, birds were placed in the cages at least 2 hours before the experiment started. At dusk, room lights were reduced to a light intensity of 0,04 lux, a typically used value for behavioral orientation tests using night migrants [e.g. 1], [ 13], [ 29]–[31]. To minimize brain activity evoked through any sensory or motoric disturbances, we only collected birds after they had been sitting relatively still and constantly awake for at least 2 hours in the cage under the low light conditions. “Relatively still” means that the birds did perform head scans [28] and did occasionally move around on the perch in all cases together with minimal (<5 mins/h) unspecific motor activity (flying around/jumping on/off the perch, as this would have led to motor-dependent activity in the brain). Each bird’s behavior was continuously observed in real-time by the experimenter with an infrared camera (840 nm) connected to a surveillance monitor to make sure that the bird is awake (eyes open) as this is a prerequisite for Cluster N activation [13].

Processing of brain tissue
At the end of the experiment, birds were killed by an overdose of Narcoren (Merial, Hallbergmoos, Germany) and transcardially perfused with 0,12 M phosphate buffered saline (PBS) followed by 4% paraformaldehyde (PFA) dissolved in PBS. The brains were dissected from the skull and post-fixed in 4% PFA dissolved in PBS for 3 hours. Tissue was cryoprotected in 30% Sucrose dissolved in PBS for 24 h and cut on a freezing microtome (Leica 1850, Solms, Germany) in six series of 40 µm thick sections in either the frontal or the sagittal plane. Sections were stored in PBS containing 0,01% Na-azide at 4°C.

Immunohistochemical stainings
Brain slices were reacted free-floating according to the immuno-ABC-technique [32]. Each incubation step was followed by rinsing sections three times in PBS for 5 minutes each. Endogenous peroxidases were inactivated by incubation with 0,3% hydrogen peroxide dissolved in distilled water for 60 minutes and unspecific binding sites were blocked by incubating the slices in 10% normal serum dissolved in PBS containing 0,3% Triton-X100 (PBS-T, Sigma, Deissenhofen, Germany) or in 10% fetal calf serum (Kraeber, Ellerbek, Germany) for 60 minutes. Slices were incubated with the primary antibody for 3 days (polyclonal rabbit raised against Egr-1/ZENK (Santa Cruz, CA), 1:1000; polyclonal rabbit raised against CtB (Sigma, Deisenhofen, Germany), 1:500 in PBS-T). Thereafter, sections were sequentially incubated for 60 minutes each with biotinylated secondary antibodies and avidin-coupled peroxidase-complex (Vector ABC Elite Kit, Vector Laboratories, Burlingame, CA). After washing, the peroxidase-activity was detected using a 3′3-diaminobenzidine (DAB; Sigma, Deisenhofen, Germany) reaction, modified by the use of β-d-glucose/ glucose-oxidase (Sigma, Deisenhofen, Germany; 33). The reaction was stopped by transferring the sections into PBS. Sections were mounted on gelatinized slides, dehydrated, and embedded in Entellan (Merck, Darmstadt, Germany).

For colocalization of both tracers or one tracer together with ZENK signals, primary antibodies (Egr-1/ZENK, 1:500; CtB, 1:300 in PBS-T) were detected by an appropriate secondary antibody (polyclonal goat raised against rabbit IgG labeled with fluorescent dyes Alexa488; Molecular Probes Europe BV, Leiden, The Netherlands, 1:400 in PBS-T). BDA was detected by streptavidine labeled with fluorescent dye Alexa 555 (Molecular Probes Europe BV, Leiden, The Netherlands, 1:400 in PBS-T). Sections were mounted on gelatinized glass slides and coverslipped with Vectashield medium (Vector Laboratories, Burlinghame, CA).

Analysis, digital processing and photomicrograph production
Sections at all levels of the brain were analyzed. Depending on the staining procedure, either a stereomicroscope (Leica M, Leica IM 50, Solms, Germany) or a confocal microscope (Leica DMR-E, Nussloch, Germany) was used for documentation of representative digital images shown in this article. Schematic drawings, labeling and layout were done using the Photoshop 6.0 and Illustrator 10.0 software (Adobe Systems, Mountain View, CA). Neuroanatomical structures were named by using brain atlases of chicken [34], pigeon [35] and canary [27]. Quantification of relative amounts of neurons expressing ZENK was done by estimating the total number of neurons on Nissl-stained sections in defined areas of Cluster N. In corresponding sections immunolabeled against ZENK protein, ZENK-positive nuclei were counted.
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The Gift of Magnetic Vision

“Maybe technology eventually turns them into something that we wouldn’t call human. But that’s a choice they make — a rational choice.” – Bruce Sterling

It’s hard to deny that Steve Haworth (iam:steve haworth) has been one of the most influential and innovative voices in body art over the past decade. In the field of implants as sculptural art he has singularly defined the art form, and with the assistance of Jesse Jarrell (iam:Mr. Bones) has continued to escalate it into increasingly refined forms. I heard a rumor recently that they’d been experimenting with magnetic implants, and I thought to myself, “cool party trick”, and checked out the pictures on Steve’s page. A fascinating letter from the client was posted along with it — he’d had a small silicone-coated neodymium magnet implanted, and it turned out to be far, far more than just a party trick!

Sensory Experimentation Somatosensory Extension Reflections by Todd M Huffman
I am now able to perceive magnetic fields in ways not naturally possible. The sensation is different than holding a magnet, as the neurons are stimulated with a higher resolution. With the implant I can detect subtle changes in polarity and strength that I cannot when equipped with a magnet in the conventional manner. Yet the most significant observations have come from another property of implants, their relative permanence to exogenous artifacts. Being able to perceive magnetic fields has expanded my conscious perception of magnetic fields ‘in the wild’.

In one sensory incident, I was walking out of the library, and I sensed the inductive anti-theft device. I have walked in and out of dozens of libraries hundreds of times, and never once have I thought about the magnetic fields passed through me to prevent me from stealing a book. I have been intellectually aware of the mechanism, but never paid attention until now. Another time I opened a can of cat food for my girlfriend’s pets, and I sensed the electric motor running. My hand was about six inches away from the electric can opener, and I was able to sense where the motor was inside of the assembly. Again it brought my attention to a magnetic source that I understood intellectually, but would have otherwise been unaware of. I feel I am one step closer to fully grokking the reality I inhabit.

The experience of my implant is not nearly as rich as my visual or auditory sensation, but nevertheless after a week it has dramatically changed the way I think about my daily sensory experience. A small magnet embedded in a finger may seem like a trivial exercise. I find it difficult to explain the significance, somewhat akin to trying to explain to a blind person what it is to see. The problem isn’t defining the technical characteristics of the visual system, but one of trying to convey what conscious perception of certain wave frequencies does to the way a person conceptualizes the world.

In modifying my body I have ever so slightly altered the way I organize the world in my mind. I eagerly await the day in which I can integrate more elaborate senses into myself. With every passing minute I try to see radiant heat, hear radio waves, and think the thoughts of those that pass by. And by better understanding what I cannot feel, I can fully appreciate what I have now.

I was floored. This seemed to me to be one of the biggest steps body modification has taken. The notion of enhancing sensation is nothing new to anyone with genital modifications, but the idea of adding something fundamentally new to the function of the body is a radical concept that only a few people have done meaningful experiments in. I had to interview Todd about his experiences, and he was happy to help us out.

BME: Tell us a bit about yourself… Where are you from?
TODD: I grew up in Los Angeles and a small town, Teutopolis, in southern Illinois. When I was growing up my main interests were in emergency medicine. I started college studying nursing, with plans to continue on to medical school. While in high school I got my certification as a Nurses Assistant, and completed a course to be an EMT. These experiences are relevant because I was very thorough in my research on body modification, the effects of magnetic fields on tissues, implant construction, and the specific procedural skill of Steve Haworth (the implant artist who worked with me on the project).

I worked as a nurse’s assistant in the St. Louis University Hospital Neurology unit, where I developed my interest in neuroscience — and my aversion to medicine. I don’t dislike the medical profession per se; I just prefer an occupation with more freedom. I moved back to California to attend California State University at Long Beach and studied neuroscience. After graduation I took a job with the Alcor Life Extension Foundation (, and will be working there for two years until I start graduate school.

One important aspect of my life is transhumanism. I have been identifying myself as a transhumanist since the age of thirteen, when I discovered the website of the Extropy Institute and the philosophical writings of Max More ( and Nick Bostrom (, among others. The transhumanist philosophy has provided a useful framework for me to build ideas and concepts upon, such as the concept and practice of attempting to extend my sensory

BME: Did you have other modifications before this particular “upgrade”?
TODD: Before this my body modifications have been limited to piercing, both cosmetic and play. Our society has perfected the art of pain avoidance and disassociation from our bodies. Piercing and other body modifications bring the mind back to the body and increase a person’s awareness of their physical self. For such a materialistic society, America has lost touch with their physical self.

BME: So this the first “functional” modification you’ve gotten?
TODD: Yes. The magnetic implant is probably the crudest form of functional implant. It pales in comparison to much more complex implants that interface directly with neurons, such as cochlear implants. As a point of clarification, my magnetic implants are more effective as a conceptual tool, rather than for real world use. The plans were more for the exploration of sensory experience than for a specific task that would increase my functional abilities.

BME: For those that aren’t familiar, could you tell us a bit about cochlear implants?
TODD: Cochlear implants are a medical device that bypasses damaged structures in the inner ear and directly stimulates the auditory nerve, allowing some deaf individuals to learn to hear and interpret sounds and speech. My involvement with cochlear implant research was analyzing the electrophysiological brainstem response of implant patients with a particular disease, auditory neuropathy. I did this for a semester as an independent project, and the bulk of my time was spent in front of a computer working with numbers. However I did on several occasions assist in the data collection procedures, and talked with people who had cochlear implants. I was fascinated with the possibility of gaining a sense with technology that was forbidden by nature.

Fortunately I have all the senses normally accorded to a human being. Current medical devices are not capable of giving me additional sensory experiences. Steve Haworth, Jesse Jarrell, and I were discussing various implants, and Jesse mentioned a friend of his who got a steel sliver in his finger and could sense speaker magnets. Jesse and I had previously discussed implanting magnets, and the idea was born. I was highly motivated to get the implant because of the possibility to explore a new sensory modality.

BME: How did you refine the idea into something functional?
TODD: I spent several months researching magnetic implants. I was concerned the magnet would attract iron particles from degraded red blood cells and cause irritation in the surrounding tissue. A significant amount of research has been done by the medical field and my concerns were alleviated. After that Jesse and I ordered a batch of neodymium magnets from a supplier and played with size combinations. After determining the sizes and shapes of the desired implants, Jesse made several prototypes. Jesse and I tested the implants to make sure the coatings were sufficient, and Jesse made the implant that was actually implanted.

BME: How was the healing?
TODD: Healing was great. I had feeling back by the next morning, and full sensitivity back in a week. The scarring is minimal, and is not noticeable unless you are looking for it. The next day my finger felt like I had slammed it in a car door, but that is expected. There has been no prolonged discomfort.

BME: Is the implant visible?
TODD: Not visible at all. If someone palpates my fingertip and knows exactly where the implant is they can feel it. A friend of mine couldn’t find it until I pointed out the location. The goal was to have it as unobtrusive and natural as possible. The reason for this was not to hide the implant from other people, but to hide it from myself. I want the sensation to seem as naturally endogenous as possible. I want the sensation to integrate as much as possible with the rest of my sensory experience.

BME: How does it feel to you in the absence of a magnetic field?
TODD: I feel nothing, just like any finger experiencing normal conditions. Humans ignore the majority of sensory experience, a necessity given the barrage of information thrown at us by reality.

BME: And when you move into a magnetic field, what does it feel like?
TODD: There are two distinct feelings I get from fields. For a static field, like a bar magnet, it feels like a smooth pressure. Imagine running your hand slowly through lukewarm water, and brushing your finger across the top of a large invisible marshmallow. That is the closest description I can give. Oscillating fields, such as electric motors, security devices, transformers, et cetera, vibrate the magnet. This sensation is much more sensitive and noticeable.

BME: How sensitive is? Can you tell the direction of a field?
TODD: The implant is rather sensitive. I can tell the polarity of a bar magnet from several inches away. So far the furthest I have felt an oscillating field has been about two and a half or three feet. That was the security system in a video store, which uses magnetic induction.

BME: You can “feel” for anti-theft devices? You’re getting all the super-villains excited!
TODD: All you would-be criminals don’t get your hopes up. I can only detect the active components of anti theft devices — those stands by the exits of stores. The actual component inside the item does not generate its own field. I just get a buzzing feeling when going through security systems.

BME: How “fine” a sense is it? Does it feel like a sense like sight or hearing, or more like a “sixth sense” in that it’s more of a “gut” or instinctual sense?
TODD: The feeling is rather fine. I can detect different frequencies in the magnetic fields. I haven’t done experiments yet to determine the sensitivity range, but I will in the near future. The sensation is rather intuitive, and exploring a magnetic field is not unlike trying to identify an object with your eyes closed.

BME: Does it feel like a sense in and of itself, or is it more of an “interface” between a sensory device and your nervous system?
TODD: The implant does not feel like an ‘alien’ artifact, it is much closer to a natural sense. When the sense is not active I don’t feel the implant and don’t really think about it. If the sensation were coming from an external source, it would feel much more like an interface object rather than an actual sensory experience.

BME: Will you expand this to your other fingers as well, or do you feel that wouldn’t add to the experience? I’m having visions of mechanics that will be able to run their fingers over an engine and diagnose problems because of imperfections in the magnetic fields.
TODD: I don’t think this type of implant will ultimately prove to be useful. However, my intentions were exploratory, and the case may be that this type of implant has many more uses. There are a few ideas I have that may involve adding more implants.

BME: Do you have plans to add other senses as well?
TODD: I would like to add as many senses as I possibly can. One area I am considering is using the implant, and others as needed, as a form of haptic feedback. Computer interaction is developing at a snail’s pace, whereas almost every other index of computer development is racing at exponential rates. Our main form of computer input — the keyboard — is over a hundred years old. Even the mouse is over thirty years old. Monitor technologies have progressed very slowly, and are fundamentally the same as they have always been. I don’t expect everyone to go out and get magnets implanted in their fingers, but as a society we need to think outside the box and devise new ways to interact with computers.

BME: Are you finding that it is having a functional impact on the way you perceive and interact with the world?
TODD: The implant has changed my perception of the world around me in a small but significant way. Information is constantly flowing around us, and we remain blissfully unaware of most of it. Having a tiny bit of that data stream pulled into your conscious awareness is a shocking experience. Functionally I have changed very little, but I am now more aware of what it is I don’t feel. There is an untold amount of information flowing around us that we don’t experience; my implant makes me think about this more.

BME: Did you do any psychological (or other) preparatory work before the implant?
TODD: Before the actual implant there were several months of planning and hypothesizing, and thus I was well prepared for the procedure and the implant. There were unexpected sensations, and some sensations were missing I thought would be noticeable. I can’t say I would recommend any particular preparation, as a person willing to put implants into themselves should be able to handle small changes in their sensory paradigm.

BME: Can I ask a little about your research work for Alcor, and how that relates to this implant?
TODD: Alcor and the body modification community have a lot in common. The classic members of both communities are individualists with strong personal identities. Neither group is afraid to push the envelope of what is accepted by the populace around them. Transhumanism is a philosophy that does not encompass all members of both communities, but I have noticed a significant level of overlap. I think this is the case because transhumanism as a philosophy encourages exploring boundaries and transforming yourself. Alcor employs me as a Research Associate, and I am part of the research and development team. My main task is to research and evaluate methods of preserving and storing neural tissue. My research at Alcor is unique because no other organization is concerned with preserving tissue in the manner we are. The research is significant not only to cryonics, but a lot of our research has applications in other areas, such as organ transplantation and storage.

All of this ties together because ultimately I am interested in pushing the boundaries. Pushing boundaries is, in my opinion, the quintessential characteristic of humankind. An a priori acceptance of the status quo on the part of our ancestors would leave you and I as naked apes hiding in the trees, or more likely, extinct. Both cryonics and body modification are controversial and exciting, just like writing or forging metal or flying.

BME: How did you meet Steve and Jesse, and what made you decide to work with them, rather than working with a doctor or more traditional medical team?
TODD: Jesse I met at a Los Angeles Futurists meeting, where we were attending a talk by Syd Mead. Later I met Steve through Isa Gordan, an artist in the Phoenix area. As Steve and Jesse became friends with me, we discussed body modification and my medical background, and Steve allowed me to observe several procedures. Steve’s protocols for infection control and cross contamination avoidance are on par with a hospital setting, and I felt confident in his technical abilities. In addition, there is a high level of artistic vision in implant work, which I do not think can be met by conventional medicine.

BME: So there were advantages to doing it without the constraints of the medical industry?
TODD: Steve and Jesse provide the professionalism and concern for safety provided by traditional medicine while incorporating artistic vision and skill. Doctors, even cosmetic surgeons, would have likely shied away from doing this type of implant work. The fear of the unknown would dissuade most doctors from assisting me in the project.

BME: Any advice for people considering adding this sense or others?
TODD: Exploring sensory experience is a fundamental quality of human beings, be it through implants or pharmaceuticals or technology. Before any experimentation you are obligated to yourself to perform thorough research into the subject, as it is very easy to harm yourself. Personal responsibility is even more important than experimentation.



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