ELECTRICAL signals in the brain regulated by a ‘molecular volume knob’ aid with learning and memory, according to a new study at Dartmouth College, Hanover, New Hampshire, USA, and could prove crucial in the treatment of numerous neurological disorders.
Memory and learning are associated with synaptic plasticity in which facilitation evokes a series of increasingly rapid spikes that amplifies the signals that change a synapse’s shape, and depression reduces the signals. Together, these two forms of plasticity maintain the balance of the brain and prevent neurological events, such as seizures. However, the measurement of the electrical impulses underlying these two forms of plasticity has been challenging in small nerve terminals due to their size.
In the study, the team utilised optical physiology measurements to overcome this size barrier and found that the electric spikes are delivered as analogue signals whose shape impacts the magnitude of chemical neurotransmitter released across the synapses, while previous studies considered the spikes to be delivered as a digital signal. This finding highlights why the brain has such a high computational power at such low energy. Postdoctoral fellow Dr Ha Cho noted: “This helps our understanding of how our brain is able to work at supercomputer levels with much lower rates of electrical impulses and the energy equivalent of a refrigerator light bulb. The more we learn about these levels of control, it helps us learn how our brains are so efficient.”
Dr Cho also noted: “The finding that these electric spikes are analogue unlocks our understanding of how the brain works to form memory and learning” and continued that: “The use of analog signals provides an easier pathway to modulate the strength of brain circuits.” Additionally, the team also identified that the potassium channel subunit Kvβ1 regulates the electrical signals explaining why loss of Kvβ1 molecules had previously been shown to negatively impact learning, memory, and sleep in mice and fruit flies.
In the future, the team plans to investigate how this discovery correlates to changes in brain metabolism that occur during ageing and cause common neurological disorders. However, for now, the team stated that: “This finding puts us on a straighter path toward being able to cure stubborn neurological disorders.”