Background: Cognitive deficit is a significant problem, which finally occurs in all schizophrenic patients. It can not be
attenuated by any antipsychotic drugs. It is well known that changes of neuronal density are correlated with learning and
memory deficits. Bacopa monnieri (Brahmi), popularly known as a cognitive enhancer, might be a novel therapeutic agent for
cognitive deficit in schizophrenia by changing cerebral neuronal density. The objective of this study was to determine the effects of Brahmi on attenuation at cognitive deficit and on the neuronal density in the prefrontal cortex, striatum and cornu ammonis subfield 1 (CA1) and 2/3 (CA2/3) of hippocampus in sub-chronic phencyclidine (PCP) rat model of schizophrenia.
Material and Method: Rats were assigned to three groups; Group-1: Control, Group-2: PCP administration and Group-3:
PCP + Brahmi. Rats were tested for cognitive ability by using the novel object recognition test. Neuronal density from a serial Nissl stain sections of the prefrontal cortex, striatum and hippocampus of rat model of schizophrenia were measured by using Image ProPlus software and manual counting.
Results: Sub-chronic administration of PCP results in cognitive deficits in novel object recognition task. This occurred alongside significantly increased neuronal density in CA1. The cognitive deficit was recovery to normal in PCP + Brahmi group and it occurred alongside significantly decreased neuronal density in CA1. On the other hand, significantly increased neuronal density was observed in CA2/3 of PCP + Brahmi group compared with PCP alone.
Conclusion: Brahmi is a potential cognitive enhancer against schizophrenia. It reduces neuronal density, most likely
glutamatergic neuron, which results in neuronal toxicity and cognitive deficit. Therefore, Brahmi has cognitive enhancement
effect by reducing glutamatergic neuron in CA1. Moreover, it also has neurogenesis effect in CA2/3, which is needed to be
investigated in the further study.

Keywords: Brahmi, Schizophrenia, Animal model, Neuronal density, Novel object recognition