motivated by curiosity.

Dynamics of propofol-induced unconsciousness across primate neocortex

06.06.16 Posted in Primate Neurophysiology Studies by

The precise neural mechanisms underlying transitions between consciousness and anesthetic-induced unconsciousness remain unclear. Here, we studied intracortical neuronal dynamics leading to propofol-induced unconsciousness by recording single-neuron activity and local field potentials directly in the functionally interconnecting somatosensory (S1) and frontal ventral premotor (PMv) network during a gradual behavioral transition from full alertness to loss of […]

Temporally coordinated deep brain stimulation in the dorsal and ventral striatum synergistically enhances associative learning

06.06.16 Posted in Primate Neurophysiology Studies by

The primate brain has the remarkable ability of mapping sensory stimuli into motor behaviors that can lead to positive outcomes. We have previously shown that during the reinforcement of visual-motor behavior, activity in the caudate nucleus is correlated with the rate of learning. Moreover, phasic microstimulation in the caudate during the reinforcement period was shown […]

Frequency-dependent representation of feedback-related information in the human medial and lateral prefrontal cortex

06.06.16 Posted in Human Neurophysiology Studies by

The feedback-related negativity (FRN) is a commonly observed potential in scalp electroencephalography (EEG) studies related to the valence of feedback about a subject’s performance. This potential classically manifests as a negative deflection in medial frontocentral EEG contacts following negative feedback. Recent work has shown prominence of theta power in the spectral composition of the FRN, […]

Sharp wave ripples during visual exploration in the primate hippocampus

06.06.16 Posted in Primate Neurophysiology Studies by

Hippocampal sharp-wave ripples (SWRs) are highly synchronous oscillatory field potentials that are thought to facilitate memory consolidation. SWRs typically occur during quiescent states, when neural activity reflecting recent experience is replayed. In rodents, SWRs also occur during brief locomotor pauses in maze exploration, where they appear to support learning during experience. In this study, we […]

An open source 3-d printed modular micro-drive system for acute neurophysiology

03.14.14 Posted in Recording Methods by

Current, commercial, electrode micro-drives that allow independent positioning of multiple electrodes are expensive. Custom designed solutions developed by individual laboratories require fabrication by experienced machinists working in well equipped machine shops and are therefore difficult to disseminate into widespread use. Here, we present an easy to assemble modular micro-drive system for acute primate neurophysiology (PriED) […]

Studying task-related activity of individual neurons in the human brain

02.17.13 Posted in Human Neurophysiology Studies by

Single neuronal studies remain the gold standard for studying brain function. Here, we describe a protocol for studying task-related single neuronal activity in human subjects during neurosurgical procedures involving microelectrode recordings. This protocol has two phases: a pre-operative and intra-operative phase. During the pre-operative phase we discuss informed consent, equipment setup, and behavioral testing. During […]

Human single neuron reward processing in the basal ganglia and anterior cingulate

01.10.13 Posted in Reviews by

Animals are fundamentally governed by rewards. It is a central component of our behavior and the pursuit of which represents the integration of a broad range of cognitive capacities. These functions take place in a distributed reward network and include regions such as the frontal cortex, cingulate cortex, basal ganglia, and midbrain dopaminergic systems (see […]

Encoding of rules by neurons in the human dorsolateral prefrontal cortex

11.21.12 Posted in Human Neurophysiology Studies by

We use rules to extend learned behavior beyond specific instances to general scenarios. The prefrontal cortex (PFC) is thought to play an important role in representing rules, as evidenced by subjects who have difficulty in following rules after PFC damage and by animal studies demonstrating rule sensitivity of individual PFC neurons. How rules are instantiated […]

Lesion procedures in psychiatric neurosurgery

11.16.12 Posted in Reviews by

Lesion procedures for psychiatric indications have a history that spans more than a century. In this review, we provide a brief history of psychiatric surgery and address the most recent literature on lesion surgery for the treatment of anxiety and mood disorders.

Human dorsal anterior cingulate cortex neurons mediate ongoing behavioural adaptation

05.17.12 Posted in Human Neurophysiology Studies by

The ability to optimize behavioural performance when confronted with continuously evolving environmental demands is a key element of human cognition. The dorsal anterior cingulate cortex (dACC), which lies on the medial surface of the frontal lobes, is important in regulating cognitive control. Hypotheses about its function include guiding reward-based decision making, monitoring for conflict between […]