10/3/25 Peter Kaskan: Intracranial stimulation in humans suggests mechanisms for manipulating circuits involved in affect, memory, and decision-making
Neuroscience brown bag
Peter Kaskan, PhD
Departments of Neurosurgery and Neuroscience, Albert Einstein College of Medicine, Bronx, NY
Date: October 3, 2025
Time: 1:25- 2:15
Location: 316 WH
Intracranial stimulation in humans suggests mechanisms for manipulating circuits involved in affect, memory, and decision-making
The amygdala has extensive connections with the anterior cingulate (ACC), medial and orbital frontal cortices, the insula, and visual cortex; areas routinely implicated in associative learning, encoding positive and negative valence, arousal, attention, and hedonic value. We have developed intracranial stimulation protocols and single-unit isolation methods in human neurosurgical participants in parallel with several behavioral tasks. To characterize temporal dynamics of spiking following intracranial stimulation of the amygdala, and compare with sites of intracranial cortical stimulation, we have analyzed recordings from over 1000 Behnke-Fried (BF) microwires implanted across the above-mentioned areas in 14 patients, while delivering single-pulse bi-phasic stimulation across adjacent BF macro-contacts during rest. Several patterns of single-unit spiking were identified using principal components analysis: 1) short-latency spiking followed by suppression; 2) delayed increases in spiking, accompanied by suppression and/or a second “wave” of activity; and 3) suppression lasting nearly 1 second. Increased spiking with late onset latencies (>150-250 ms) was apparent in some cases, suggesting some spikes were triggered by indirect/multi-synaptic connections, perhaps involving thalamocortical circuits. The reliable identification of spikes elicited by intracranial stimulation is necessary to determine how experimentally activated (“stimulated”) neurons might influence ongoing behaviors during task performance. By surveying areas activated, we can also identify areas that are not affected by stimulation and therefore unlikely to influence behavior. By probing activity elicited in the human brain by direct intracranial stimulation, we can broaden our understanding of functional circuits in humans involving the amygdala.