\documentclass{article}
\usepackage[left=2in,right=2in,top=0.5in,bottom=0.5in]{geometry}
\usepackage{graphicx}



\begin{document}

\begin{center}
  \textbf{Somatic injection}
\end{center}

\begin{tabular}{@{}p{0.49\linewidth}p{0.49\linewidth}@{}}
  Low proximal CaL, cvode off
  \includegraphics[width=\linewidth]{BPAP/Soma/bpap-orig-cv0-0}
  \includegraphics[width=\linewidth]{BPAP/Soma/bpap-orig-cv0-1}
  \includegraphics[width=\linewidth]{BPAP/Soma/bpap-orig-cv0-2} 
  &
  High proximal CaL, cvode off
  \includegraphics[width=\linewidth]{BPAP/Soma/bpap-calh-cv0-0}
  \includegraphics[width=\linewidth]{BPAP/Soma/bpap-calh-cv0-1}
  \includegraphics[width=\linewidth]{BPAP/Soma/bpap-calh-cv0-2} 
  \\
  Low proximal CaL, cvode on
  \includegraphics[width=\linewidth]{BPAP/Soma/bpap-orig-cv1-0}
  \includegraphics[width=\linewidth]{BPAP/Soma/bpap-orig-cv1-1}
  \includegraphics[width=\linewidth]{BPAP/Soma/bpap-orig-cv1-2} 
  &
  High proximal CaL, cvode on
  \includegraphics[width=\linewidth]{BPAP/Soma/bpap-calh-cv1-0}
  \includegraphics[width=\linewidth]{BPAP/Soma/bpap-calh-cv1-1}
  \includegraphics[width=\linewidth]{BPAP/Soma/bpap-calh-cv1-2} 
\end{tabular}

\pagebreak[4]

\begin{center}
  \textbf{Dendrite 62 injection}
\end{center}

\begin{tabular}{@{}p{0.49\linewidth}p{0.49\linewidth}@{}}
  Low proximal CaL, cvode off
  \includegraphics[width=\linewidth]{BPAP/Dend62/bpap-orig-cv0-0}
  \includegraphics[width=\linewidth]{BPAP/Dend62/bpap-orig-cv0-1}
  \includegraphics[width=\linewidth]{BPAP/Dend62/bpap-orig-cv0-2} 
  &
  High proximal CaL, cvode off
  \includegraphics[width=\linewidth]{BPAP/Dend62/bpap-calh-cv0-0}
  \includegraphics[width=\linewidth]{BPAP/Dend62/bpap-calh-cv0-1}
  \includegraphics[width=\linewidth]{BPAP/Dend62/bpap-calh-cv0-2} 
  \\
  Low proximal CaL, cvode on
  \includegraphics[width=\linewidth]{BPAP/Dend62/bpap-orig-cv1-0}
  \includegraphics[width=\linewidth]{BPAP/Dend62/bpap-orig-cv1-1}
  \includegraphics[width=\linewidth]{BPAP/Dend62/bpap-orig-cv1-2} 
  &
  High proximal CaL, cvode on
  \includegraphics[width=\linewidth]{BPAP/Dend62/bpap-calh-cv1-0}
  \includegraphics[width=\linewidth]{BPAP/Dend62/bpap-calh-cv1-1}
  \includegraphics[width=\linewidth]{BPAP/Dend62/bpap-calh-cv1-2} 
\end{tabular}

\pagebreak[4]

\begin{center}
  \textbf{Dendrite 64 injection}
\end{center}

\begin{tabular}{@{}p{0.49\linewidth}p{0.49\linewidth}@{}}
  Low proximal CaL, cvode off
  \includegraphics[width=\linewidth]{BPAP/Dend64/bpap-orig-cv0-0}
  \includegraphics[width=\linewidth]{BPAP/Dend64/bpap-orig-cv0-1}
  \includegraphics[width=\linewidth]{BPAP/Dend64/bpap-orig-cv0-2} 
  &
  High proximal CaL, cvode off
  \includegraphics[width=\linewidth]{BPAP/Dend64/bpap-calh-cv0-0}
  \includegraphics[width=\linewidth]{BPAP/Dend64/bpap-calh-cv0-1}
  \includegraphics[width=\linewidth]{BPAP/Dend64/bpap-calh-cv0-2} 
  \\
  Low proximal CaL, cvode on
  \includegraphics[width=\linewidth]{BPAP/Dend64/bpap-orig-cv1-0}
  \includegraphics[width=\linewidth]{BPAP/Dend64/bpap-orig-cv1-1}
  \includegraphics[width=\linewidth]{BPAP/Dend64/bpap-orig-cv1-2} 
  &
  High proximal CaL, cvode on
  \includegraphics[width=\linewidth]{BPAP/Dend64/bpap-calh-cv1-0}
  \includegraphics[width=\linewidth]{BPAP/Dend64/bpap-calh-cv1-1}
  \includegraphics[width=\linewidth]{BPAP/Dend64/bpap-calh-cv1-2} 
\end{tabular}

\end{document}