Final answer:
The false statement about chemical synapses is that pre- and postsynaptic currents are always similar.
Statement 4, that pre- and postsynaptic currents are always similar, is false because these currents can differ significantly based on the excitatory or inhibitory nature of the chemical synapse.
Step-by-step explanation:
Statement 4) Pre- and postsynaptic currents are always similar is false. In chemical synapses, the presynaptic neuron releases neurotransmitters into the synaptic cleft, which bind to receptors on the postsynaptic neuron. These neurotransmitters can cause either excitatory or inhibitory postsynaptic currents, but they are not always similar. Excitatory currents depolarize the postsynaptic membrane, while inhibitory currents hyperpolarize it, resulting in different effects on the postsynaptic neuron.
Statement 4, that pre- and postsynaptic currents are always similar, is false because these currents can differ significantly based on the excitatory or inhibitory nature of the chemical synapse.
The false statement regarding chemical synapses is that "Pre- and postsynaptic currents are always similar." This is not correct because the currents can be very different depending on whether the synapse is excitatory or inhibitory. Chemical synapses are indeed unidirectional, meaning they transmit information from presynaptic to postsynaptic neurons in only one direction. Moreover, they exhibit high plasticity, allowing them to strengthen or weaken over time in response to activity. Lastly, neurotransmitters do diffuse across the synaptic cleft in a chemical synapse.