Measuring Single Neuron Activity in the Brain (SUNAN)

Single Unit Neurophysiological Architecture of the Neocortex (SUNAN)

The SUNAN (Single Unit Neurophysiological Architecture of the Neocortex) study aims to understand how individual brain cells called neurons interact and communicate, and how the neurons can be affected in neurological disease. Using an advanced digital probe called the "Neuropixels probe," which is as thin as a human hair, the investigators can record electrical activity from individual neurons on the outmost layer of the brain (cerebral cortex). This electrical (neurophysiological) activity recording technique allows the investigators to isolate and monitor single-neuron activity from the human brain during planned neurosurgical operations in real time.

Study Overview

• Status: Not yet recruiting
• Conditions: Neurological Diseases or Conditions
• Intervention / Treatment: Device: Neuropixels recording intraoperatively during planned neurosurgery

Detailed Description

The SUNAN study plans to recruit fifty patients scheduled for brain surgery, such as for tumour removal or operations that involve the fluid (cerebrospinal fluid) within the brain, at the National Hospital for Neurology and Neurosurgery. Participation is voluntary, and the suitability will be assessed by the participant's neurosurgeon.

Patients who participate in SUNAN will undergo their planned neurosurgery as per standard of care with the additional step of a neurophysiological recording made from the brain using a Neuropixels probe. This recording step and the data collected will not affect the rest of the patients care which will proceed in the usual way and the data is collected solely for scientific purposes.

The investigators believe that the insights gained from these electrical recordings from individual neurons will deepen our understanding of brain function and potentially lead to improved diagnosis and treatment of neurological diseases.

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: William Muirhead; Phone Number: +44 (0) 20 7679 2000; Email: will.muirhead@nhs.net
• Study Contact Backup: Name: Grace Auld; Phone Number: +44 (0) 20 7679 2000; Email: g.auld@ucl.ac.uk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

1. Aged 18 years and over.
2. Documented informed consent to participate.

3. Undergoing a transcranial neurosurgical procedure at the National Hospital for Neurology and Neurosurgery (NHNN) in which part of the cerebral cortex will be:

   • Resected e.g., as removal of part of a tumour or epilepsy focused. Or
   • Transgressed as part of the surgical approach to reach a deeper target e.g., resection of a deep tumour or cavernoma.

   Or

   • Transgressed by the passage of a surgical implant e.g., a ventriculoperitoneal shunt catheter or deep brain stimulation electrode.

4. Surgery felt to be technically suitable for the neurophysiological recording technique by the Chief Investigator and responsible Consultant Neurosurgeon. For example, participants having surgery in an unusual position may present problems for the neurophysiological recording step.

Exclusion Criteria:

1. Participants who lack the capacity to give informed consent.
2. Participants who are pregnant or breast feeding at the time of surgery.
3. Participants deemed to be unsuitable for recruitment to the study by the responsible Consultant Neurosurgeon. If in the view of the treating consultant involvement in the study would compromise the patient's surgery or present an unacceptable risk to them, they will not be recruited to the study. For example, if the participant does not meet the standard of care preoperative checks.
4. Concern from the Consultant Neurosurgeon or treating Anaesthetist that there would be an unreasonable burden on the patient to participate in the study. For example, risk due to increased length of anaesthetic time.
5. For participants requiring anaesthesia for their pre-planned brain surgery, an American Society of Anaesthesiologists (ASA) physical status classification system score of 4 and higher.
6. Participants unable to understand English sufficiently well to read the patient facing documents and consent in English.
7. Participants not undergoing their treatment through National Health Service (NHS) care (i.e. private patients are excluded).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Neuropixels recording; Participants undergoing planned neurosurgery that undergo a maximum of 15 minutes neurophysiological recording using Neuropixels

Device: Neuropixels recording intraoperatively during planned neurosurgery; The SUNAN study is a basic science study involving a procedure to record single-unit neurophysiological activity with human participants who are already undergoing a transcranial neurosurgical procedure on the brain. As part of the surgery, a region of cerebral cortex on the convexity of the brain will be: Resected e.g., as removal of part of a tumour or epilepsy focused. Or; Transgressed as part of the surgical approach to reach a deeper target e.g., resection of a deep tumour or cavernoma. Or • Transgressed by the passage of a surgical implant e.g., a ventriculoperitoneal shunt catheter or deep brain stimulation electrode. Within this region of the brain that is going to be resected or transgressed, the research team will undertake a single-unit resolution neurophysiological recording (NR) using a digital neural probe (Neuropixels) for a maximum of 15 minutes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Single units isolated	Outcome name - Descriptive reporting on the number of well isolated single neuronal units observed during neurophysiological recording of the brain during planned neurosurgery. Metric/method of measurement - Neurophysiological activity of the brain will be described through analysis of electrical activity recorded. The detection of spikes represents depolarisation of single neuronal units ("single-units"). Well isolated single-units will be defined by clustering metrics, interval spike interval violations and/or other neurophysiological analysis. Descriptive reporting will include the number of individual units recorded, their spiking rates and correlation.	Timepoint - At time of planned neurosurgery.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Experience of using large scale single-unit recording	Secondary outcome measures will be reported for each participant to gather information on the recording technique. For example, a description of the recording setting may include the arrangement of ground and reference electrodes as well as the operative set-up. Reporting on the experience of using large scale single-unit recording techniques in humans undergoing neurosurgery.	Through study completion, an average of 1 year
Iterations made to the surgical and electrophysiological technique	Reporting on iterations made to the surgical and electrophysiological technique over the course of the study.	Through study completion, an average of 1 year
Potential refinements in technique	Reporting on potential refinements that could be made to the described technique which could enable better quality data and that could be of benefit to other researchers conducting similar work. For example, equipment set-up/noise restrictions in theatre.	Through study completion, an average of 1 year

Collaborators and Investigators

• Sponsor: University College, London
• Collaborators: Francis Crick Institute

Study record dates

Study Major Dates

• Study Start (Estimated): February 1, 2025
• Primary Completion (Estimated): February 1, 2027
• Study Completion (Estimated): February 1, 2028

Study Registration Dates

• First Submitted: December 20, 2024
• First Submitted That Met QC Criteria: January 6, 2025
• First Posted (Actual): March 25, 2025

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 6, 2025
• Last Verified: December 1, 2024

More Information

Terms related to this study

• Keywords: Neurosurgery; Neurophysiology; Cortical; Neuron activity; Single unit; Neuropixels
• Additional Relevant MeSH Terms: Nervous System Diseases
• Other Study ID Numbers: 159671

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: The data sharing plans for the current study are unknown and will be made available at a later date.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No