Time Multiplexed Active Neural Probe with 678 Parallel Recording Sites

We present a high density CMOS neural probe with active electrodes (pixels), consisting of dedicated in-situ circuits for signal source amplification. The complete probe contains 1356 neuron size (20x20 μm2) pixels densely packed on a 50 μm thick, 100 μm wide and 8 mm long shank. It allows simultaneous highperformance recording from 678 electrodes and a possibility to simultaneously observe all of the 1356 electrodes with increased noise. This considerably surpasses the state of the art active neural probes in electrode count and flexibility. The measured action potential band noise is 12.4 μVrms, with just 3 μW power dissipation per electrode amplifier and 45 μW per channel (including data transmission)

Time Multiplexed Active Neural Probe with 1356 Parallel Recording Sites

We present a high electrode density and high channel count CMOS (complementary metal-oxide-semiconductor) active neural probe containing 1344 neuron sized recording pixels (20 µm × 20 µm) and 12 reference pixels (20 µm × 80 µm), densely packed on a 50 µm thick, 100 µm wide, and 8 mm long shank. The active electrodes or pixels consist of dedicated in-situ circuits for signal source amplification, which are directly located under each electrode. The probe supports the simultaneous recording of all 1356 electrodes with sufficient signal to noise ratio for typical neuroscience applications. For enhanced performance, further noise reduction can be achieved while using half of the electrodes (678). Both of these numbers considerably surpass the state-of-the art active neural probes in both electrode count and number of recording channels. The measured input referred noise in the action potential band is 12.4 µVrms, while using 678 electrodes, with just 3 µW power dissipation per pixel and 45 µW per read-out channel (including data transmission)

Anisotropic etching in (3 1 1) Si to fabricate sharp resorbable polymer microneedles carrying neural electrode arrays

Polymer microneedles that get resorbed after insertion in the body have several interesting applications, for example in the insertion of ultra-flexible electrode arrays in neural tissue. In this work, we explore the use of molds created by etching in (3 1 1) silicon as a basis for the fabrication of such microneedles. Such molds can be etched anisotropically to much sharper angles compared to standard (1 0 0) silicon. It is demonstrated that sharp poly lactic-co-glycolic acid (PLGA) microneedles can be fabricated using the molds. It is also shown that by simple thermal bonding the fabricated PLGA microneedles can be combined with an ultra-flexible polyimide-based thin-film electrode array.status: publishe

Insertion mechanics of silicon-based neural implants for rodents

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Histological alterations induced by electrode implantation and electrical stimulation in the human brain: A review

Objectives. Electrical brain stimulation is used as a treatment for patients with intractable chronic pain and movement disorders. However, the implantation of electrodes and electrical stimulation may induce histological changes around the electrode tip. We aimed to review the histological changes in humans that were electrically stimulated in the brain. Methods. We traced 26 autopsy studies of which 19 patients received cerebellar stimulation and 37 patients deep brain stimulation.Results. Electrode implantation and electrical stimulation induced in part of the cases formation of a fibrous sheath around the electrode, loss of fairly large neurons, and limited gliosis. Macroscopic lesions were present in only some cases, mostly due to pulling at the extension cable in the postoperative evaluation period preceding definite implantation of the electrode wire and stimulator. Conclusions. Electrical brain stimulation induces histological changes in some patients. According to electrical brain stimulation studies in animals, these changes can be related to the charge and charge density per phase (and their interaction).status: publishe

Electrical stimulation in the lateral hypothalamus in rats in the activity-based anorexia model - Laboratory investigation

Object. One quarter of patients with anorexia nervosa have a poor outcome and continue to suffer chronically or die. Electrical brain stimulation may be of therapeutic benefit in some of these patients; however, the brain target for inducing symptom relief is unknown. In this study, the authors evaluated the effects of acute and chronic electrical stimulation in the lateral hypothalamus on food intake, locomotor activity, and survival time in rats in an activity-based anorexia model.status: publishe

Ultra-compact integrated electrical and optical silicone probe for recording and illumination in vivo

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Towards a noise prediction model for in vivo neural recording

The signal-to-noise ratio of in vivo extracellular neural recordings with microelectrodes is influenced by many factors including the impedance of the electrode-tissue interface, the noise of the recording equipment and biological background noise from distant neurons. In this work we study the different noise sources affecting the quality of neural signals. We propose a simplified noise model as an analytical tool to predict the noise of an electrode given its geometrical dimensions and impedance characteristics. With this tool we are able to quantify different noise sources, which is important to determine realistic noise specifications for the design of electronic neural recording interfaces.status: publishe

The effects of electrical stimulation or an electrolytic lesion in the mediodorsal thalamus of the rat on survival, body weight, food intake, and running activity in the activity-based anorexia model

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